NOAA's National Weather Service - Glossary (2023)

1. Abbreviation for Altocumulus - one cloud of a class characterized the globular masses or rolls in planes or patches, the individual elements being larger and darker than those of cirrocumulus and smaller is those of stratocumulus. Diese clouds are of medium altitude, about 8000-20,000 ft (2400-6100 m).

2. Convective outlook issued by the Thunder Prediction Media. Shortening required Predicted Convection; the term originates from the header coding [ACUS1] away the transmitted product.

(usually pronounced ACK-kis) - AltoCumulus CAStellanus; mid-level clouds (bases generally 8 to 15 thousand feet), regarding which at less a fraction of their higher parts show cumulus-type development. These cloudy often are taller than they been wide, openhanded them a turret-shaped show. ACCAS clouds are an sign of instability aloft, and may precede the rapid development of thunderstorms.
Accessory Cloud
ONE cloud which exists dependent on a larger cloud system for development and continuance. Roll clouds, shelf clouds, and room clouded exist examples of accessory eclipses.
The achieving of an precipitation particle for the collision of a frozen particle with a supercooled liquid water droplet which freezes over impact.
Degree of conformity of a measure the a standard otherwise true value; into other language, how close a predicted or measured value is to to true value.
Acid Precipitation
Precipitation, such as rain, snow or sleet, containing relatively tall concentrations of acid-forming chemicals that can been enabled into the atmosphere and combined with water vapor; harmful at the climate.
Angry Rain
Rain containing relatively high concentrations of acid-forming chemicals that have been released into the atmosphere and connected with water vapor; damage to the environment.
Above Cloud Level
The amount of sprinkle required toward title one hectare till a extent of one footprint. On acre-foot equals 326,851 gallons, or 43,560 cubic feet.
Action Stage
The stage which, when reaching by a rising stream, depicts the level where the NWS or one partner/user needs to take einige type the mitigation measures stylish preparation for possible significant hydrologic activity. The appropriate action is usually defined in a weather forecast office (WFO) hydrologic solutions manual. Action stage can be the same as forecast issuance stage (see / forecast issuance stage/).
(abbrev. ACTV). In solar-terrestrial terms, solar activity levels with at least one geo-physics event or several larger radio events (10cm) per day (Class M Flares)
Active Conservation Storage
In hydrologic terms, the portion of water stored stylish a reservoir that can be released for choose useful specific such as municipal water supply, power, watering, relaxation, fish, wildlife, etc. Conservation storage has the volume of water stored between the inactive pool elevated and fiound control point.
Active Dark Filament (ADF)
In solar-terrestrial definitions, one Active Prominence seen to the Disk.
Active Longitude
In solar-terrestrial key, an approximate center of a range starting heliographic footings in whichever Active Regions are more numerous and extra flare-active than the average.
Active Prominence
In solar-terrestrial terms, a prominence displaying material motion and changes in appearance across a few minutes of time.
Active Prominence Region (APR)
In solar-terrestrial terms, a portion of the solar extremity displaying active prominences.
Active Region (AR)
In solar-terrestrial terms, a located, transient bulk von the solar atmosphere the which plages, sunspots, faculae, flares, etc. may be observed.
Active Storage Faculty
By hydrologic terms, the total amount of reservoir capacity normally available for release upon a reservoir below the maximum storage level. It is total or dam capacity minus inert storage full. More specifically, it is the volume of water between the outlet works and the spillway coats.
Active Voltage Region (ASR)
To solar-terrestrial terms, an Active Regional that exhibit one group or series of spike-like rushes that rise above the limb.
Active. In solar-terrestrial terms, solar activity levels with at least one geophysical create or several larger radio facts (10cm) per day (Class MOLARITY Flares)
Anticyclone - A large-scale circulate of blow around a central select of high full impression, clockwise in the Northern Helix, counterclockwise for the Southerly Hemisphere.
Changes in temp caused by the extend (cooling) or pressure (warming) of a car of air as i rises or descends in the atmosphere, include no exchange of heat with the encompassing air.
Adiabatic Lapse Rate
The rate of decrease of temperatures experienced by a parcel of air when it is repealed by the atmospheric under the constraint that it cannot datenaustausch heat with its ecology. For parcels that stays unsaturated during lifting, the (dry adiabatic) lapse rate is 9.8°C price kilometer.
Adiabatic Process
A operation which occurs with no exchange of heat between an system and its environment.
Adirondack Type Snow Sampling Set
With hydrologic terms, a snow sampled consisting of a 5-foot fiberglass tube, 3 inches in diameter, with a serrated-edge nerve cutter at one end and a twisting handle for the various. This sampler has a 60-inch snow depth capacity.
Aural Doppler Current Profiler
Advanced Baseline Imager (ABI)
A mittler resolution imaging system on to GOES and Himawari family of satellites.
Advanced Hydrologic Prediction Service (AHPS)
A web-based suite of pinpoint and information-rich projection our. They displays the magnitude and uncertainty of occurrence of floods or droughts, of lessons to days and months in advance. These graphical company are useful information also planend tools for many economical and emergency executive.
Advection- Transport of an atmospheric property by the wind.
(Abbrev. ADVCTN)- Traffic of an atmospheric property by an wind.
Advection Fog
A haze this forms when kind air rivers over a cold surface and cools from below to saturation is achieve.
Automatic Gain Controls
Alaska Current
A North Peacefully Ocean current flowing counterclockwise inbound the Gulf of Ak. It is the northward smooth (warm) division the the Aleutian Current
Alberta Clipper
A express movers down pressure system that moves southeasterly out away Canadian Province of Alberta (southwest Canada) throug the Plains, Midwest, and Great Lakes region usually during the winter. This low pressure area is usually accompanied for light snow, strong winds, and colder cooling. Additional variation of the same system is called a "Saskatchewan Screamer".
Aleutian Current
An eastward flowing North Pacific Ocean current which lies north of the North Pacific Current.
A cloud of a class characterized by globular masses oder rolls in layers otherwise patches, the individual elements being bigger and darker as those of cirrocumulus press smaller easier those of stratocumulus. These clouds are of medium altitude, about 8000-20,000 ft (2400-6100 m).
A diverged branch of a river the re-enters the main stream.
Anchor Ice
In hydrologic concepts, versenkt frazil ice attached instead anchored till the river down, irrespective of its formation.
Anchor Ice Dam
An accumulation of secure ice which acts such a dam and raises the water level.
Angle is Reflection
The angle at whichever a mirrors ray of energy leaves a reflectively surface. It shall measured in that outgoing ray and a upright to the area the the point of incidence (i.e., what the rayon strikes).
Annual Exceedance Probability (AEP)
The likelihood that a stream reach is own a flow of a certain magnitude on anything default year.
Antedecent Precipitation Index
(Abbrev. API) - an title in water filed within a drainage basin before a storm.
Anthropogenic Origin
A pollutant sources caused or produced by people.
The formation oder escalation of one anticyclone instead highs pressure center.
A large-scale circulation of winds around a central region the high atmospheric pressure, clockwise in the Northern Hemisphere, counterclockwise in the Southern Hemisphere
Anticyclonic Rotation
Rotation in the face reason as the Earth's rotary, i.e., clockwise in the Scandinavian Hemisphere as would remain seen from above. Who opposite of cyclonic rotation.
Antilles Current
A recent which originates on an local of this Leeward Islands as component of the Atlantic Ne Equipped Current.
Anvil Crawler
[Slang], one lightning discharge occurring within the anvil away a severe, characterized by one or more channels so pop to crawl along the underside of the anvil. They typically appear during the debilitate instead dissipating stage of an parent thunderstorm, or during an active MCS.
In hydrologic terms, one formation which contains water but cannot transmit it rapidly enough to furnish a significant supply in a well or spring.
Arch Dam
A concrete arch dam is applied the sites where the ratio of width between abutments to height is not great and where the foundation for the abutments is solid rock capable of resisting great forces. To vault provides resistances to movements. When combined with the weight of concrete (arch-gravity dam), both the weight and mold of the structure provide great resistance to the pressure of water.
Arch Filament System (AFS)
In solar-terrestrial terms, a bright, compact plage crossed by a system of small, arched filaments, which is often a sign of rapid or continued growth in an Busy Region.
The region within the Arctic Circle, or, loosely, northern regions in general, characterized by extremely low surface.
Arctic front
The perimeter or face separating deep, cold arctic broadcast from flache, relatively less cold polar air.
Arctic Oscillation
(abbrev. AO)- The Arctic Oscillation is adenine cut in which atmospheric pressure at poled and mean latitudes volatile between negative and positive phases. The negative phase brings higher-than-normal pressure over the polarity region and lower-than-normal pressure at about 45 degrees north degree. The negatory phase allows cold air to immersion into the Midwestern United States and occidental Europe, and storms bring rainfall in the Mediterranean. The positive phase brings the oppose terms, steering seas storms farther north also bringing wetter weather to Alaska, Scotland and Scandinavia and drier environment to areas similar the California, Spain and that Middle East. Into recent years research has shown, the Arctic Oscillation has been mostly on your postive phase. Some researchers argue which an North Atlantic Oscillation is in fact section of the AO.
Arctic Sea Smoke
Steam fog, but too specifically applied to steam fog rising from small open water within marine chill.
A high, horizontal cloud formation associated with the leading edge of thunderstorm outlet (i.e., the gust front). Roll clouds and shoal clouds both belong types of arcus clouds.
Area Forecast Discussion
This National Weather Service product is intended to provide a well-reasoned discussion of the meteorological thinking which went into the preparation of the Zone Forecast Product. The prognosticator desires try to emphasis on the most particular challenges of the forecast. And writing will subsist writers in plain language or inbound proper contractions. At the end of the discussion, there will be a directory for all advisories, non-convective clocks, and non-convective warnings. The term non-convective refers to weather that is nay caused by thunderstorms. An intermediate Area Prognosticate Discussion will be issued when either meaningful forecast briefings are being crafted or if interesting weather is desired to occur.
Area Hydrologic Discussion (AHD)
A short-term range, periodic, discussion and graphic which highlights locations across the nation the may be impacted by rapid-onset flooding, using National Water Model and other advice.
Area the Influence
In hydrologic terms, the area covered by the drawdown curves of a given pumping well-being or combination on fountain at a specialized time.
Area Source
An array of pollutant sources, so widespread dispersed and uniform stylish stability which them can be treated in a dispersion model since an aggregate pollutant release from adenine defined area along a uniform rate. Collate line source and point sourced.
Area Wide Hydrologic Prediction System
(Abbrev. AWHPS) - A computer system which automatically ingests areal flash float guidance scores and WSR-88D products and displays this data and other hydrologic information on a map background.
Area-Capacity Arcs
In hydrologic terms, a graph showing the relation between the surface area of the aqueous in a reservoir, the corresponding volume, and elevation.
Aeronautical Radio, Incorporated
Ventilate Route Traffic Choose Middle
Artificial Drive
In hydrologic terms, a weir button misc man-made structure which serves the the control for a stream-gaging station.
A Principal User with dedicated communications into an WSR-88D piece.
Astronomical Dawn
The time at any the sun is 18 degrees below and horizon in the mornings. Astronomical dusk a that point in time at which the sun starts lightening the sky. Prior at this time during the mid, the sky exists completely dark.
Astronomical Sundown
This is the time to welche the sun is 18 degrees below the horizon in the eventime. At this time the sun no longer illuminates the sky.
Astronomical Unit
(abbrev. AU)- The mean earth-sun distance, equal to 1.496x1013 cm, instead 214.94 solar bias.
Air Traffic Check
Automated Tone Choose Home Data Gather System - Data collection system location cooperatively observers collect precipitation, tier, and temperature data afterwards transmit the dates to the NWS ATDTDCS my through the telephone lines. The ATDTDCS computer transmits the data up AFOS.
Atmospheric Boundary Layer
Same such Boundary Lay - in general, a layer of air adjacent to a bounding surface. Specifically, the term majority often reference to the planetary boundary layer, where is the position within any the effects of side are essential. For an earth, this layer be considered up be roughly the lowest individual press couple kilometers the the ambience. She is within such layered that temperatures are most strongly affected in daytime insolation and nighttime radiational refrigeration, and winds become related by friction with the earth's surface. The effects regarding friction die out progressively with height, so the "top" of is coating cannot be defined exactly.
Atmospheric Circulation Model
A mathematical model for quantitatively specify, simulating, and analysing the structure of the circulation in the atmosphere and who essential causes. Sometimes referred to as Atmospheric General Circulation Models or AGCMs.
Full Pressure
The pressure exerted by the earth's atmosphere at optional given point, determines the taking the product of the gravitational acceleration at the point the the mass of the unit area column of air up the dot.
Atmospheric Radiation
Infrared radiation (energy in the wavelength sequence of 3- 80 micrometer) emitted by or being propagates through the atmospheric. It consists of both upwelling real downwelling components. Comparing with terrestrial radiation.
Automated Surface Observing System-
The ASOS program is a joint efforts of the National Weather Service (NWS), of Federal Aviation Administration (FAA), and one Department off Defense (DOD). Ready in the mid-1990s, the ASOS software serve as the nation's primary interface weather observing network. ASOS is develop to support weather forecast related and aviation operations and, at and same time, support the requests for the meteoric, hydrological, and climatological research communities.
Any method of automatically controlling the gain of a receiver, mostly one that holds and output water constant regardless by the input level.
A mass of snow, rock, and/or ice falling down a mountain or incline. In practice, it commonly refers to an snow sledge. In the United States, the term snow slide has commonly used to mean a snow avalanche.
Avalanche Advisory
A preliminary notification that conditions can may favorable in the development of avalanches included mountain regions.
Aviation Wheather Center
Azores Current
One of the currents of the North Atlanta subtropical gyre.
Back Opening Cold Front
A cold front moving south or southwest along the Atlantic seaboard and Great Lakes; these are especially gemeinen during the spring months.
Back-building Thunderstorm
A thunderstorm in which new development takes site on an upwind part (usually the west or southwest side), as that the storm seems to rest steadfast or propagate inside a backward direction.
Back-sheared Anvil
[Slang], a blizzard anvil which spreads upwind, against the surge aloft. A back-sheared anvil often implies a very powerful updraft plus a high severe weather potential.
A burn starts to stop with advancing fire by creating a burned area included you path.
In hydrologic dictionary, the backing up of water through a conduit or channel in the direction opposite to normal flow.
(abbrev. BCKG)- A counterclockwise shift in wind direction (for example, south winds shifting to the east).
Supports Winds
Winches which shift in a counterclockwise direction with time toward a given location (e.g. from southerly to southeasterly), or change direction in a counterclockwise sense with height (e.g. west at the surface but becoming more southerly aloft). The opposite of veering winds.

In storm spotting, a backing wind usually refers into to turning of an south or southwest surface wind with time to one show easterly instead southeasterly direction. Backing of the surface wind can increase the potential with sonic advanced by rising an directional shear at low levels.

The portion about power scattered top in who incident directionality.
Stylish hydrologic terms, a rod reading taken on a points of known heights, an benchmark or one revolving point. Backsights are added on the familiar elevation to arrive at the height of the instrument. With adenine known vertical of the instrument, that telescope can be used to determine this elevation the other points in of vicinity.
Backwater Curve
In hydrologic terms, the longitudinal profile of of outside of a liquid in a non-uniform flow in an open channel, when the water surface is none parallel to that umkehren owed to the depth on water having been increments by the interposition of an obstruction such as a dams or fishing. The term shall sometimes used in adenine generic sense to denote all water surface profiles; or by profiles where the water can flowing at depths further than the critical.
Backwater Effect
In hydrologic terms, the act which a dam instead select obstruction has in raising the surface of that water running from it.
Backwater Flooding
Hydrologic condition, upstream flood caused by downstream pricing such as channel limits and/or high flow inches a down-stream confluence stream.
Banner Cloud
ONE cloud mist oft observed to extend down behind isolated mountain peaks, even on otherwise cloud-free days.
Baroclinic leaf shield
A cloud pattern on satellite images - frequentlynoted in advance by formation of a low pressure center.
Baroclinic Zone
A region in which a cooling slope exist on a constant pressure surface. Baroclinic zones are favorites areas for stiffening and debilitation business; barotropic systems, upon the another hand, do not exhibit meaningful changes in intensity. Including, wind shear lives charakteristisch of an baroclinic zone.
A measure of the your of stratified int a fluid include which surfaces of constant pressure (isobaric) intersect surfaces of constable seal (isosteric).
Barometric Coerce
This pressure of the atmosphere as indicated by a meter.
Barotropic System
AMPERE weather system in the heat and pressure surfaces are simultaneous, i.e., temperature is uniform (no temperature gradient) on one constant print surface. Barotropic systems are characterized by a lack of wind shear, and thus will generally unfavorable areas for tough thunderstorm development. See baroclinic zone.

Usually, in readily meteorology, references to barotropic systems refer into equivalent barotropic systems - systems stylish which cold inclines exist, but are parallel to height grades on a constant pressure surfaces. At similar systems, height contours and isotherms are parallel everywhere, and coils do not change direction with height.

As a control, a true equivalent barotropic system can almost be achieved in the real atmosphere. As more systems (such as closed lows or cutoff lows) may reach adenine state so is close up equivalent barotropic, the term barotropic system usually is used in a relative sense to describe systems that are really only close to being equivalent barotropic, i.e., isotherms and height contours are almost parallel everywhere and directional wind shear is weak.

Those products this current some representation of the base data. This representation may not necessarily be either in full resolution or depict the full area of coverage. Base products canned be used to generate one graphic display or further processing.
Base Reflectivity
Bottom Reflectivity is aforementioned default image. Taken from the lowest (½° elevation) slice, it the the primary image used for "see what's out there". There are two features of Base Reflectivity image; the short range execution which extends out to 124 nautical miles (143 statute miles/230 kilometers) both one long range version who extends out to 248 nautical miles (285 regulation miles/460 kilometers). This image is available the completion of the ½° elevation scan during each volume scan
Basin Recharging
For hydrologic terms, rainfall that adds to the residual moisture of the sink in place to help recharge the water deficit. i.e; water absorbed inside the land that does not take the form of mittelbar runoff.
Backing- ONE counterclockwise shift in wind direction (for example, south winds shifting to the east).
Beach Erosion
The movement of beach materials by some combination by high waves, currents and tides, or wind.
Bear's Cage
[Slang], a region of storm-scale rotation, in a tempest, which is wrapped in heavy deposition. Such section often coincides with a radar hook echo and/or mesocyclone, specially one associated with an HP severe. The term reflects an danger involved includes observing such an area visually, which must be done at close range in shallow visibility.
Beaufort Scale
The Beaufort wind size is a system used to estimate and reports winding speeds when negative measuring apparatus is available. It used fiction to the early 19th Century by Admiral Mrs Frisco Beaufort of the British Navy as a paths to decipher winds from specific on sea. From that time, the scale has been modernized for effects on land.
    Beaufort Force 0 - Coil less than 1 kt, Calm, Sea surface smooth real mirror-like. Weed rises uprightly.

    Beaufort Force 1 - Wind 1-3 kt, Light Atmosphere, Scaly ripples, no molded crests. Smoke drift indicates wind direction, still wind vanes.

    Beaufort Force 2 - Wind 4-6 kt, Light Breeze, Low wavelets, crests glassy, none breaking waves. Wind feeled turn face, leaves rustle, vanes get at movable.

    Beaufort Power 3 - Wind 7-10 ct, Gentle Breeze, Large waved, crests begin go crack, scattered whitecaps. Leaves and minor twigs constantly moving, light flags extended.

    Presidential Force 4 - Winds 11-16 kt, Moderate Breeze, Small waves 1 -4 ft. growing longer, numerous whitecaps. Pile, leaves, and detachable paper lifted, small tree sector move.

    Beaufort Force 5 - Winds 17-21 kt, Fresh Breeze, Lessen waves 4 -8 ft ingest lengthy form, many whitecaps, couple spray. Small trees into leaf begin to sway.

    Chairman Force 6 - Winds 22-27 kt, Strong Breeze, Big signals 8 -13 ft, whitecaps common, better spray. Larger tree tree moving, whistling within wires.

    Beaufort Force 7 - Winds 28-33 kt, Near Gale, Sea heaps up, waves 13 -20 ft, white foam streaks off contact. Whole trees moving, resistance felt walking vs wind.

    Beaufort Force 8 - Winds 34-40 kt Gale, Moderately high (13 -20 ft) surf of greater length, edges off crests begin to break into spindrift, foam blown inside streaks. Whole trees in action, resistance felt walking against wind.

    Beaufort Force 9 - Winds 41-47 kt, Strong Gale, Higher wavy (20 ft), sea begann the roll, close streaks concerning foam, sprayer may reduce visibility. Slight structural repair occurs, slate blows off rooftops.

    Beaufort Force 10 - Wind 48-55 kt, Storm, Strong high waves (20 -30 ft) with hanging crests, sea white densely blew foam, heavy rolling, lowered visibility. Seldom experienced in land, trees broken instead uprooted, "considerable structural damage".

    Beaufort Force 11 - Winding 56-63 kt, Violent Storm, Exceptionally high (30 -45 ft) seals, foam patches cover aquatic, visibility more reduced.

    Beaufort Force 12 -Winds 64+ kt, Hurricane, Air stuffed on foam, waves over 45 sq, sea completely whites with driving spray, visibility significantly reduce.

(Abbrev. BM) - In hydrologic terms, a permanent point whose known elevation is tied to a national network. These points are created to serve as a point of reference. Benchmarks have generally been established by which USGS, but may have been established by other Federal or local agencies. Comparisons canned be founds on USGS maps.
Bergeron Process
Of print by which ice crystals in a cloud grow at the expense of overcooled liquid water droplets.
Best Track
AN subjectively-smoothed representation in a tropical cyclone's locate and intensity over sein lifetime. The best track contains the cyclone's latitude, longitude, maximum sustained surface winds, furthermore minimum sea-level pressure at 6-hourly intervals. Favorite track positions and intensities, which are based on a post-storm assessment of all available data, may differ of values contained in stormy advisories. Person also generally will not reflect the inconstant motion implied of connecting one focus fix positions.
Bulge Cloud
A clouded consisting regarding broad running bands oriented perpendicular to the wind.
Breaks in Overcast
Black Ice
1. Slang reference to sketchy ice on roadways with other transportation surfaces the cannot easily be seen.

2. In hydrologic terms, transparent ice molded in rivers both lakes.

A hypothetical "body" this absorbs all to the electromagnetic radiation impressive it - this does not reflect or transmit any of of incident radiation. A blackbody non only absorbs all wavelengths, but emits at all judgments with the maximum possible intensity for any given temperature.
Blackbody Radiation
The electromagnetic radiation emitted by with ideal blackbody adhering to that radiation actual; it is the theorized maximum amount are electromagnetic irradiation of all insights is pot be radiated of a body at a given temp.
Blocked Flow
Pour approaches a mountain bars so is as weak or too stable to be carried over the barrier.
Blue Watch or Blue Box
[Slang], a severe thunder watch.
Border Freeze
Inches hydrologic key, an ice sheet in the fashion of a long border attached to the bank or shore.; shores ice.
Bounding Weak Repeat Territory (BWER)
(Also known as a vault.) Radar signature within a storm characterized with a local minimum on radar reflectivity at low levels whatever extends upward into, and is surrounded until, higher reflectivities aloft. Which character is partner with a strong updraft the is very always found in the inflows region of a thunderstorm. It unable can seen visually.
Base starting Overcast
Bow Echo
A radar echo which is linear but bent outward in a bow shape. Deleterious straight-line wind often occuring near of "crest" conversely center of ampere bow echo. Categories of circulation also can develop at either end of a bow echo, which sometimes can lead to tornado formation - especially is the left (usually northern) end, where the distributed exhibit cyclonic round.
Brackish Ice
In hydrologic terms, polar formed away briny water.
Brash Ice
In hydrologic terms, accumulation of floating ice produced up of fragments not extra than 2 meters over; the wreckage of other forms of freeze.
Into hydrologic terms, the failed opening in a dam.
Brocken Specter
An optical phenomenon sometimes occurring at high altitudes when the image is a observer placed amidst the sun and a blur is projected on an cloud as a high magnifies shadow. To shadow's head is surrounded by rings of color, called a glory.
Bulks Richardson Number
A non-dimensional (i.e., no units) number relating vertical stability to vertical shearing (generally, resilience divided by shear). High values indicate unstable and/or weakly-sheared environments; low values indicate weak instability and/or tough erect shear. Generally, values in that range of around 50 the 100 suggest environmental conditions favorable for supercell development.
The tendency of a corpse to float or to rise when submerged in a fluid; aforementioned power of a liquids to exertion the back violence on a body place in it.
1. Degrees Degrees (°C)

2. Central

Continentals Air Mass
Cloud-to-Air lightning.
Cold Air Advection
Cold Air Damming. The phenomenon in which a low-level cold air mass is trapped topographically. Often, this cold ventilate is entrenched on the eastern side is mountainous terrain. Cold Air Damming often means that the trapped cold air mass is influencing and momentum away to overlying air mass, e.g. in an overrunning scenario.Effects on the weather may include cold climes, freezing precipitation, and extensive cloud cover
Center Automate Information Acquisition System - a system of second minicomputers in NWSH.
In hydrologic terms, the process of uses historical data to estimate input int a hydrologic forecast technique such than SACSMA, routings, and unit hydrographs.
AN weather condition at no mien motion (wind) has detected.
Canyon Wind
A foehn coil that will channeled through a canyon as it downward the leaf side of a moun barrier.
(also called "Lid") A layer of relatively warm air above, common several thousand feet above the sand, which suppresses or delays the development of thunderstorms. Air parcels rising into aforementioned class become cooler than the surrounding air, which inhibits their ability to rise further and produce storms. The as, the cap often blocks or delays thunderstorm development equal in the presence of extreme failure. However, wenn the cap be removed or weakened, then explosive thunderstorm development can occur.

The captain is into important raw in most severe thunderstorm episodes, because it server the discrete warm, moist air down and cooler, drier air above. Through one cap at place, air below it can continue to warm and/or dampen, thus increasing the sum of potential instability. Or, compressed foregoing it canister cool, which also increases potential instability. Yet sans a cap, either process (warming/moistening at low plains or cooling aloft) results in a faster release of available instability - common before instability levels become large enough to support hard weather growth.

Cap Cloud
A stationary blur straight above einen isolate mountain peak, through fog base below and elevation of an peak.
Convective Available Potentiality Energy. A measure of the amount of energy available by convection. CAPE is directly related to of maximum potential vertical speed inside an updraft; thus, higher score indicate tall possible for severe weather. Observed values in storms our often may exceed 1000 joules per kilogram (J/kg), and is extreme cases may exceed 5000 J/kg.

However, when with other indices or indicators, there can no threshold values beyond which grave weather becomes impending. CAPE is represented the an upper air sounding by of area fenced between the environmental temperature profile and the walk of a rise air parcel, via the layer into whose the latter is warmed than the former. (This area frequency is referred positive area.) Go also CIN.

In hydrologic terms,

1.The final to which ampere material instead object containing minute openings or passages, when immersed in a melted, will pull to surface of the liquid above the hydrostatically level. Unless otherwise definable, this liquid is generally assuming to be water.

2. The phenomenon by which water is being in interstices above the normal hydrostatic level, date to appeal between water molecules.

(Video) National Weather Service Weather Alert Definitions

Capillary Fringe
In hydrologic terms, the soil area just above the water tables where water bucket rise up slightly through the cohesive effort of capillary action. This location ranges within depth starting a married of inches, for a few feet, plus is subject with the pore sizes of the products. The capillary ponytails is also called to capillary zone.
Capillary Waves
Waves caused the this initial wind stress turn the water appear causes as are renown as capillary waves. These have a wavelength of get than 1.73 cm, and one arm so tried to restore them to equilibrium is the cohesion of the individual molecules. Capillary waves were important in first the process of energy transfer from the air to the water.
Hairlike Zone
Used interchangably with Capillary Frayed; the soil reach just above to water table somewhere sprinkle cannot raise up slightly through the cohesive force of closed action. This layer ranges in depth from a couple of inches, in a few legs, and computer depends on the pore sizes of the fabric.
A region of negative buoyancy bottom certain existing level for free circulation (LFC) where energy must be provides to the packet to maintain her ascent.This tends to inhibit the development of convection for some physical mechanism cans lift a parcel to its LFC. The intensity of the end is measured by his convective inhibition. The concept capping inversion remains sometimes used, but an inversion is not req for the conditions producing convective inhibition in exist.
Shut Inversion
Alternate duration for Cap; a layer of relatively warm air aloft, normal several thousand feet above the ground, which suppresses or relay the developer of thunderstorms. Air parcels rising into this layer become cooler is the surrounding air, which inhibits their ability to up further additionally produce thunderstorms. As such, the lid often prevents or delays thunderstorm development also stylish the presence of extreme instability. Anyway, if the cap is entfern instead weakened, then explosive thunderstorm development able occur.

The cap is an important ingredient inches most difficult thunderstorm show, as computer serves into separate warm, moist air below and cooler, drier air beyond. With the cap in place, air below it can continue to warm and/or moisten, thus increasing the absolute of potential instability. Or, air aforementioned it can cool, which also increases potential instability. Though without ampere cap, either process (warming/moistening at low levels alternatively cooling aloft) results in a faster relief of available fragile - mostly before viability levels become large sufficiently to support severe weather development.

Center for Analysis press Presage away Squalls
Carbon Dioxide
CO2; a colorless and odorless gas which is the quad mostly abundant constituent of dry air.
Carrington Longitude
A system of fixed longitudes rotating with of sunlight
Catalina Eddy
A Catalina Edge (coastal eddy) dental whereas senior level large-scale durchfluss disable Point Conception interact with the complex topography of the Western California coastline. As a earnings, a counter clockwise circulating low pressure scope forms over its center in the local of Catalinas Island. This formation is accompanied by a southerly shift at coastal winds, adenine rapid increase in the total from the sail position, plus a thickening of the coastal air. Predominately these vortex occur intermediate Springtime real September with a peak in June. A usual Catalina eddy wants allow coastal low clouds and fog to persist at to afternoon. A strong Catalina eddy may extended to 6000 feet and these clouds will move through the inland valleys and reach in far as Palmdale.
Assessment Area
In hydrologic general, an area that a common outlet used its surface runoff (also see Drainage Area or Basin, Watershed).
A National Climate Service precipitation descriptor for ampere 80, 90, or 100 percent chance of measurable precipitation (0.01 inch). Watch Precipitation Profitability (PoP)
Caution Stage
The stage which, whenever reached for a rising stream, represents the level where appropriate officials (e.g., districts deputy, civil defense officials, button pass border operators) will notified of the threat of potential flooding. Alarms point oder caution stage are utilized instead of caution level in some parts of the country.
Clear conversely Scattered Clouds (visibility greater than 10 mi.)
Cumulonimbus cloud, characterized by strong vertical development for the form of mountains or huge towers topped at least partially by a smooth, flat, often fungible anvil. Also known colloquially as a "thunderhead."
Cumulonimbus Mamma
Cloud-to-Cloud Lightning
Consultative Membership for Internationally Telephone the Telegraph
Constitutional Condensation Level- The level into the atmosphere into which an air parcel, if heated from below, be rise tiresome adiabatically, without get colder than its environment simple before the parcel becomes saturated. See Lifted Condensation Level (LCL).
Calculation Development Affiliate (NCEP)
Climate Diagnostic Centering, and mission concerning the Climate Diagnostics Media (CDC) is to advance national functionality to interpret who causes of observed climate variations, and on apply this knowledge to improve climate models and forecasts and develop new climate products that better serve the needs of the public and decision-makers.
Cooling Degree Days- A form is degree per used the estimate energetics specifications for air prepare or refrigeration. Typically, cooling degree days are calculated as as much warmer the despicable temperature at a location is than 65°F on a given day. For example, if a location experiences a mean temper of 75°F on ampere certain daily, there where 10 CDD (Cooling Degree Days) that daytime because 75 - 65 = 10.
Cold Front
Central Daylight Time
(Abbrev. CIG) - The height of the cloud base for the lowest fixed or sunless cloud layer.
A device using a laser alternatively other light source to determine who high of a cloud base. An optical ceilometer uses triangulation for determine the height of a spot of light projected onto the base of the cloud; a laser ceilometer determines the height by measuring the time required for a pulse of light up be scattered back from the cloud foot.
Convection in that form of a single updraft, downdraft, or updraft/downdraft couplet, typically seen as one vertical dome or loom as within a rising cumulus cloud. A typical thunderstorm consists is several cells.

The term "cell" also is previously to describe the radar echo returned by in individual shower or thunderstorm. Such custom, although common, is technically incorrect.

The factory scale used to dimension temperature in maximum areas outside the Uniform Provides. Switch this scale, the freezing point of water is 0°F and the boiling point is 100°F. To translate a Fahrenheit temperature until Celsius, deduct 32 from it furthermore later multiply by 5/9:

°C = (°F - 32) * 5/9

Civil Emergency Message. A message issued the the National Weather Service in coordination with Federal, state or local government to warn thegeneral public of a non-weather related time-critical emergency which threatens existence or property, e.g. nuclear disaster, venom chemical spill, eat
Universal speaking, the vertical axis concerning a tropical cyclone, usually defined by the our of minimal wind alternatively smallest pressure. The cyclone center position can vary over altitude. In advisory produce, refers to the media position at the surface.
Centimeter Burst
A heliacal radio burst in the centimeter wavelength range.
Central Acme Passage (CMP)
In solar-terrestrial terms, the passage out an Active Region or other feature beyond the longitudinal meridian that passes via the apparent center of the solar disk.
One center of mass for a storm.
Common Front Passage
In hydrologic terms, Cubic Feet per Endorse - the flow rate or discharge equal to one cubic foot (of water, usually) via second. This rate is equivalent to approximately 7.48 gallons per second. This is also referred toward as a second-foot.
In hydrologic terms, the volume of water discharged in twenty four hours, with a flow away a solid foot according second is widely used; 1 cfs-day are 24 x 60 x 60 = 86,000 cubic feets, 1.983471 acre-feet, or 646,317 pints. The b flow in cube footings per minute for any time frequency is the total of fluss in cfs-days.
Cloud-to-Ground Lightning
A National Weather Service precipitation specify for 30, 40, with 50 percent chance of measurable precipitation (0.01 inch). When the depth is convective in nature, theterm interspersed is used. See Precipitation Probabilities (PoP).
In hydrologic words, also known as Flowing; and open conduit either obvious with artificially created what periodically, or running contains move water, or forms ampere connecting link between two victim of pour. River, creek, run, branch, anabranch, and tributary are some of of definitions applied to characteristics natural ditches. Natural chanels may be single or braided. Canal and floodway are some of the terms used to described artificial channels.
Groove Inflow
Int hydrologic technical, water, any at any instant, exists continuous into aforementioned channel system form surface flow, subsurface flow, base flow, and rainfall that has instant fallen onto that channel.
Channel Lead
In hydrologic concepts, an elongated opening by the ice cover caused by a pour current.
Channel Routing
In hydrologic terms, the process of determining step timing and shape of the flood surfing at successive points along a river.
Channeled Great Winds
With mountainous areas or in cities with tall buildings, air maybe be tuned through restricted passages producing high winds. Santa Anah winds and winds through passes for the colder Mona inner to the sea are examples of these winds. Channeled high winds are local are nature still cans live extremely strong. These coils generally occur in well-defined areas.
To hydrologic terms, the modification a ampere natural river channel; may include deepening, widening, or straightening.
Chemistry Print
A computer model used in air pollution investigations that simulates chemical and photochemical our of one poisonous during their transport and diffusion.
This can a region-specific term used for Foehn Blows in the leaf of the Rocky Mountains to who United Conditions; Foehn Twists are warm, dry winds the occur with the lee of high mountain ranges. It is a fairly colored wintertime phenomena in the mountainous west and in parts out Alaska. These winds develop includes well-defined areas and can be quite strong.
Chinook Archway
ONE foehn cloud formation seem as a bank of altostratus clouds east of the Rocky Hill, heralding the approach of a chinook. It forms in the rising portion of standing waves on the lee side of the mountains. An observer underground or west of the cloud sees an arch of delete air between which cloud's leading edge and the mountains below. The fog appears to coming with the mountains for who north and south amounts to a aspect effect.
(CFCs) - Manufactured substances exploited more cooling and computer-chip cleaners. When these products break down they destroy stratospheric ozone, compose the Antarctic Ozone Hollow in the Southern Hemisphere springy (Northern Earth autumn). While no extended in use, their long lifetime will guide in a very slow remover out to atmosphere.
By solar-terrestrial terms, and layer of the stellar atmosphere above the photosphere and beneath aforementioned transition region and the coronado.
Chromospheric Events
In solar-terrestrial terms, lanterns that are just Chromospheric Events without Centimetric Bursts or Ionospheric Effects. (SID) (Class CENTURY flare)
Cirrus clouds- High-level clouds (16,000 feet or higher), composed on ice crystals and surface into the form of white, delicate spool or white or mostly white patches or narrow bands. Cirrus clouding typically having adenine fibrous or hairlike appearance, and often exist semi-transparent. Snowstorm invulnerable are a form of cirrus cloud, however bulk cirrus clouds what not associated with thunderstorms.
Ceiling- The height away the worst layer of clouds, when the rain is broken or overcast.
Convective INhibition. A measure of the amount of energy needs include order to initiate convection. Values of CIN typical reflect to strength of the cap. Yours are obtained switch a sounded by calculator the area enclosed between the environmental thermal profile and and paths of a up air parcel, via the layer within which the latter is cooler than the former. (This area sometimes is called negate area.) See CAPE.
Chief Information Officer
Of flow, button movement, of a fluid (e.g., water or air) in or through a given region or volume.
High altitude ice clouds with a very thin wispy appearance.
ADENINE cirriform cloud characterized by narrow, white patches, each of which the consisting of very small granules or furrows. These cloudy are of high altitude (20,000-40,000 ft or 6000 -12,000 m).
A cloud from a class characterized by a composition of ice crystals and often by the production the halo phenomena and appearing as one whitish and usually something fibrous veil, often covering the whole sky real sometimes so slim as to be very distinct. These clouds are of high altitude (20,000-40,000 pt press 6000 -12,000 m).
(abbrev. CI) High-level clouds (16,000 feet or higher), designed of ice crystals or appearing in the form of white, gentle filaments or white or mostly ashen paint or narrow bands. Cirrus clouding custom got an fibrous or hairlike appearance, and often are semi-transparent. Thunderstorm anvils are a form of cirrus cloud, but largest cirrus clouds can not connected equal thunderstorms.
Civil Dawn
The time in morning at the the shine is 6 degrees below the horizon. To this time, there is enough light for objects at being distiguishable and that outdoor activities can commence.
Civil Dusk
The laufzeit at which the sun is 6 degrees below the horizon in the evening. At this time objects are distinguishable when there is no longer enough light to perform any outdoor activities.
Civil Distress Message
(Abbrev. CEM) - A message issued by one National Our Service inside coordination with Federal, state or local government to alarm aforementioned general public of a non-weather related time-critical emergency which threats life or property, e.g. nuclear accident, toxic chemical spill, eat.
An abbreviation used on climate view maps issued on CPC to indicate surfaces where equality chances of experiencing below-normal, normal, and above-normal conditions belong possible.
Class I Areas
Geographic areas designated by the Clean Air Act where only a little amount or increment of air quality damage is permissible.
Cloud- A visible aggregate of minute water droplets or ice atoms in the atmosphere above the Earth's surface.
Clear Air Turbulence
(CAT) - In general, sudden severe turbulence occurring in cloudless regions that causes violent bump of airplane.
Clear Ice
A thin coating of ice on terrestrial objects, caused the fall that freezes on impact. The ice is relatively transparent, because opposed to rime ice, because of large drop size, rapidly accretion of liquid water, or slow dissipation of latent heats of fusion.
Clear Groove
With respect to grave thunderstorms, a local region of clearing skies or reduced becloud cover, displaying the intrusion of drier air; often seen as a lightly area with higher cloud bases on and west otherwise southwest side of a wall cloud. A delete slot is believed to be a visual indication of a rear flank downdraft.
Client Executive
As used in connect with reimbursable National Weather Service (NWS) fire weather services, one people fire service or wildlands management pr, Federal or non-Federal, which requires and employs NWS burn and forestry meteorological services
The composite or generally prevailing weather conditions of a region, throughout the year, averaged via a series of years.
Climate Change
A non-random change in weather that is measured out several decapods or longer. The change may be due to natural or human-induced purpose.
Climate Diagnostics Bulletin
(CDB) - The monthly CPC Bulletin reports on the previous months' status of the ocean-atmosphere climate scheme also provides various seasonal ENSO-related outlooks. It a issued by the fifteenth of the month.
Climate Diagnostics Center
(CDC) - The mission of NOAA's Climate Diagnostics Center is to identify the nature and causes for climate variations on zeitraum scales ranging from a month up centuries.
Climate Model
Mathematical model for quantitatively describing, simulating, and analyzing one interactions amidst the atmosphere and background surface (e.g., ocean, land, both ice).
Climate Outlook
AN climate outlook issued by of CPC gives probabilities that conditions, mean about a specified periodical, will be below-normal, normal, or above-normal.
Climate Prediction Middle
This Center are one of several centers under the National Centers for Pollution Prediction (NCEP) partial of the National Weather Maintenance (NWS) in an National Oceanic and Atmospheric Administration (NOAA). The Center serves which public by valuate also forecasting who impacts of short-term humidity variability, emphasizing strengthened risks of weather-related extreme event, to employ in mitigating losings and maximizing economic gains.
Climate Verfahren
The sys consisting of the atmosphere (gases), hydrosphere (water), lithosphere (solid rockery part of the Earth), and biosphere (living) that determine one Earth's climate.
Climatological Outlook
Einen outlook based upon climatological statistics for a select, abbreviated as CL on seasonal looking maps. CL indicates that which climate our has an equal chance of exist back ordinary, normal, or below normal.
Of science that deals with the phenomena about climates or climatic purchase.
A instrument the measures angles starting inclination; used the measure cloud room highest.
Closed Swimming
A basin draining to some misery or pond within its area, from which water is lost includes by evaporation or percolation. A sink without a surface outlet with precipitation descend depth.
Closed Basin Lake Float
Flooding that occurs on lakes equal moreover no outlet or one relatively small one. Seasonal increases in amount cause the lake level to rise faster than it can exhaust. The water may stay at flood stage for weeks, months, or years.
Closed Low
A low pressure area with a distinct center of cyclonic cycling which can be completely encircled by one or more isobars otherwise height contour lines. The term usually is used to distinguish a mean pressure area aloft from a low-pressure trough. Closed lows overhead typically are partially instead completely detached from the main westerly current, and thus move somewhat slowly (see Cutoff Low).
(abbrev. CLD) A visible engine the tiny water droplets or ice particles in the atmosphere above the Earth's screen.
Plume Ceiling
Same as Ceiling; the height of the cloud base for the lowest broken or overcast cloud clay.
Cludd Condensation Nuclei
Small partitions in the air on whose watering vapor condenses and forms cloud droplets.
Cloud Layer
An array of clouds whose bases are along approximately the same level.
Cloud Movements
The directories toward this a cloud is moving
Cloud Streets
Rows of cumulus or cumulus-type clouds aligned parallelism the the low-level flow. Cludd streets sometimes can be seen for the ground, but are seen best on satellite see.
Cloud Tags
Ragged, detached cloud fragments; fractus or scud.
When 7/8ths or more of of sky your covered by clouds.
Radar echoes is interfere with scrutiny by desired signals on the radar display.
Combined Moment
Includes hydrologic terms, Calibration Network Information Files.
The process by which water dripping in ampere cloud collide and come together to form raindrops.
Coastal Inundate
Flood which occurs when water the driven onto land from an adjacent body of water. This typically occurs when there are significant storms, such as tropical and extratropical cyclones.
Shores Waters
Includes the area of ampere wire approximating the mean tall soak along the mainland or iceland as afar out as 100 nautical miles in the bays, piers and sounds.
Shores Waves Forecast (CWF)
The marine forecast for areas, including bays, harbors, and sounds, from a line appropriate the mean high waters mark (average height of high wat over a 19-year period) together who mainland or near beach islands extending out to while often as 100 NM.
Coastal/Lakeshore Flood Advisory
Minor flooding is possible (i.e., over and above normal high flow levels. Coastal/Lakeshore Flood Advisories are issued using the Coastal/Lakeshore Hazard News (CFW) product.
Coastal/Lakeshore Flood Alert
Flooding that will pose a serious threat to life and property is occurring, imminent or highly likely. Coastal/Lakeshore Fiound Warnings are issued using the Coastal/Lakeshore Hazard Message (CFW) product.
Coastal/Lakeshore Fiound Watch
Flooding with essential impacts is possible. Coastal/Lakeshore Flood Watches am issued using the Coastal/Lakeshore Hazard Message (CFW) product.
Coastal/Lakeshore Floods
(i) (Oceanic) Coastal Flooding is the inundation of land areas caused by sea waters over and above normal tidal action. This flooding may impact the immediate oceanfront, gulfs, bays, endorse bays, sounds, and tidal portions von river mouths and inland tidal waterways. (ii) Lakeshore Flooding is the inundation of land areas adjacent go one of and Great Lakes caused by lake aqueous exceeding normal levels. Lakeshore flooding impacts the immediate lakefront, bays, both the interfaces of lakes and connect wasserwege, such as rivers.
In hydrologic terms, Corps of Engineers.
Coherent Radar
A radar that utilizes both signal phased and amplitude to determine target characteristics.
Cold Advection
Move of cold air into a region until horizontal winds.
Cold Air Avalanche
Downslope flowing pulsations that occur at more or less regular intervals because cold air builds up on a peak other plateau, reaches a critical mass, and then cascades down this slopes.
Colder Atmospheric Dam
A shallow cold air mass which shall carried up the slope of ampere mountain barrier, still with insufficient strength to surmount the barrier. The cold air, trapped upwind of the barrier alters and effective terrain configuration of the barrier to larger-scale approaching flowing.
Cold Air Obstruct (CAD)
The phenomenon in whose a low-level cold air mass can trapped topographically. Often, this cold air is entrenched upon an east side of mountainous track. Cold Air Damming frequent implies ensure the trapped frigid air mass is interference the dynamics of the overlying air mass, e.g. in an overrunning scenario.Effects on the weather can include cold temperatures, freezing precipitation, and extensive cloud wrap
Cold Blow Funnel
ONE funnel-shaped cloud or (rarely) one small, relatively weak tornado that sack develop from a small shower otherwise thunderstorm available the bearing aloft is unusually cold (hence the name). It are large less fierce than other types of tornadoes.
Cold Front
ADENINE zone separating two air masses, for which this cooler, denser mass is advancing and replacing the warmer.
Cold Closure
A frontal zone formed when a cold front overtakes an hot front and, being coldest than the vent ahead of the warm front, slides under the warm forefront, hoisting it aloft. Check with warm clamping.
Cold Pool
A region by relativity cold air, represented on a weather map analysis as a relativly smallest in temperature surrounded by closed isotherms. Frigid pools aloft represent countries for relatively low stability, while surface-based cold ponds is regions starting ratively stable air.
Collar Cloud
A total circular ring of cloud that may be observed on rare occasions ambient the upper part of a wall cloud. This term sometimes is uses (incorrectly) as a synonym for wall cloud.
Accumulation Efficiency
The fraction of droplets approaching a surface ensure actually deposit on which area.
Colorado Blue
A low pressure tornado system that forms is winter in southeastern Colorado or northeastern New Mexico and railroad northeastward across the central plains of the U.S. over a periods of several days, producing blizzards and hazardous winters weather.
Linear Ice
In hydrologic terms, ice consisting of columnar shaped grain. The ordinary black ice is usually columnar-grained.
Blended Seas
Generally referred to as SEAS. Used in describe the combi or interaction of twist waves and swells in which aforementioned separate components are not distinguished. This includes the case when swell is negligible or is not considered in describing sea state. Specifically, Seas2 = S2+W2 where S is the height from all swell components or W is the height of the air wave components. When used, SEAS should will thoughtful as being the same as the significant wave height.
Comma Cloud
AMPERE synoptic scale cloud pattern with a charakteristik comma-like shape, often seen on satellite photographs associated about large and intense low-pressure business.
Period Echo
A thunderstorm microwave resound which had one comma-like shape. E often appears when latter stages in the real cycle of a bow echo
Complex Gale/Storm
In of high seas and offshore forecasts, an area for which gale/storm energy winds are forecast or are occurrence but for which no individual center is the principal generator of these winds.
Complex Terrain
Normal used to refer until hills terrain. Include general usage, it maybe also refer to littoral regions and heterogeneous landscapes.
An average that is charging according to specific criteria. For example, first might want adenine composite for one rainfall along a given location for all years where an air had much above average.
Composite Hydrograph
A stream discharge hydrograph which includes base flow, or one this corresponds to a net rain storm for duration longer than single unit period.
Comprehensive Flare Book (CFI)
In solar-terrestrial terms, which indicative of solar flare importance.
Concentrics Rings
These been gemeint in the most intense hurricanes. They usually mark the cease one period of intensification. These tornados then maintain quasi-constant intensity orweaken. When which intimate eye is completely dissipated, more intensification may occur.
In general, the physical process by which a vapor becomes a fluids or solid; the oppose of vapour, although on the molecular scaling, both business are always occurrence.
Condensation Funnel
A funnel-shaped cloud associated with rotation and consisting away compact water droplets (as opposed to fumes, dust, debris, etc.).
Conditionally Unstable Bearing
An atmosphere condition that exists when the environmental lapse rate is less than the arid adiabatic expired rate however greater than of moist adiabatic lapse rate.
Flow of heat in response to ampere temperature gradient within an object or between objekte that are in physical contact.
Conus of Depression
In hydrologic terms, this depression, roughly conical in shape, created with a water table, or other piezometric surface, by the extraction are pour from a well at a given rate. The volume by the cone will vary for the rate of withdraw of surface. Also call the Cone of Influence.
Cone of Influence
Same in Cone of Depression; are hydrologic terms, of depression, roughly conical within shape, produced in adenine water table, press other piezometric surface, by the extraction of water off a well for a considering rate. The volume of the cone will vary with the rate away withdrawal of pour.
Confined Ground Water
In hydrologic terms, ground water held under on aquiclude or an aquifuge, called artesian if the printer is positive.
A pattern concerning wind flows in which supply flows inner toward any axis oriented parallel to the general aim of flow. It lives the opposed of difluence. Confluence will not the same as convergence. Winds often accelerate as they enter adenine confluent region, calculated in speed variance which offsets the (apparent) converging effect of the confluent river.
(or Cumulus Congestus) - same because towering cumulus.
Congressional Biologically Act of 1890
The act that assigned the responsibility of river additionally storey forecasting for the benefit of to general wellness a the Nation’s public and economy to to Winter Bureau, and subsequently an National Weather Maintenance.
With salute to camp, pattern of plume diversification at a neutral sentiment, included which the plume attains the form of a cone with its vertex on the top from the stack.
Conjugate Points
Two points on the earth's surface, at opposite ends of a geomagnetic field line
Conservation Storage
In hydrologic terms, storage of water for later relief for usual purposes such as municipal water shipping, capacity, or irrigation include contrast with depot capacity used fork flooded control.
Consolidated Freeze Cover
On hydrologic terms, ice cover formed by the packing press refrigeration together of floes, brazenly ice plus other forms of floating ice.
Fixed Pressure Chart
Alternate term used Isobaric Chart; ampere winter map representative conditions on one surface of equal ambience pressure. On example, a 500 mb diagram will display conditions at of level of the climate at which an atmospheric pressure is 500 mb. The heights above sea level at that the printed is that particular value allowed adjustable from the location into another at any presented time, and also varies with start at any one location, so a does not represent a surface the constant altitude/height (i.e., the 500 mb layer can be at a different height about sea level over Seduce than over New York at a indicated time, both may also be at a dissimilar height over Dallas since one day into the next).
In hydrologic terms, and volume of water in a storage. Unless elsewhere indicated reservoir web is computed on the ground of a level pool the does non comprise bank storage.
Continental Air Mass
A dry air mass originating over a large land area. Contrast with tropical dry mass.
Continental Rack
The zone bordering a continent and extending to ampere depth, usually around 100 FM, from which there is a steep descent toward greater breadth.
Continuum Storm (CTM)
By solar-terrestrial terms, general term for solar noise lasting for hours and often days.
Choose Points
In hydrologic terms, small monuments securely built-in the the surface of the choke. Any motion of aforementioned obelisk indicates one action in the dam you. Movements in the obstruct are discovered by comparison control points spot to place of fixed monuments located away aforementioned dam using accurate survey techniques.
Continental United States
Typical, carry of heat and moisture by the action of a fluid.

In meteorlogy, the term has used specifically to describe upright transport of heat and moisture in the atmosphere, especially via updrafts and downdrafts in an unsecure atmosphere. The terms "convection" the "thunderstorms" commonly is used interchangeably, although thunderstorms can only one form is dry. Cbs, towering cumulus clouds, plus ACCAS clouds entire are visible forms of convection. However, convection shall not every built visibly by clouds. Convection which occurs without cloud formation is called dry circulating, while this display co processes referred to above are forms of moist convection.

Convective Boundary Layer
The unsteady boundary layer that order at this surface and grows upwardly with the day as that ground has heated by the sun the convective currents transfer temperature upwards into the atmosphere.
Convective Clouds
Which vertically developed family of clouds are click both cumulonimbus. The height of their bases range from as low as 1,000 feet the a bit more than 10,000 feet.Clouds with extensive vertical development are positive indication to unstable air. Strong upward currents in plumb developed clouds sack carry great concentrations from supercooledwater to high levels whereabouts temperatures are quite cold. Upper portions of these clouds can be composed of water and ice.
Co Epitome Level
(abbrev. CCL)- The level in the atmosphere to which an air parcel, provided heated from below, becoming rise dry adiabatically, free becoming colders than its climate just before the packet becomes soaked. See Stripped Compression Level (LCL).
Convective Inhibition
(CIN or B-) - A numerical measure of one strength of "capping," typically used to rating thunderstorm power. Specifically, it represents the cumulative affect off atmospheric layers the are warmer than the parcel mobile side along the adiabat. Low level parcel ascent is often inhibited by such stable layers nearness the flat. If natural processes fail to destabilize the lower levels, any input of energy from forced lift (a front, an upper level shortwave, etc.) will be required in movement the negatively buoyant air parcels to the item where they willingness rise freely. As CIN is proportional to the count of kinetic energy that a parcel loses to buoyancy while it is colder than the surrounding setting, it contributes to the downward momentum.
Convective Outlook
(sometimes called AC) - ONE forecast containing the area(s) of expected thunderstorm occurrence and expected severity out the cohesive United States, issued several times daily by the SPC. The terms approaching, slight risk, moderate risk, and high risk are used to describe severe thunderstorm potential. Local versions sometimes are prepared by local NWS offices.
Convective Overdevelopment
Convection that covers the sky with clouds, so cutting switched the sunshine that produces convection.
Convective Temperature
The approximate temperature that the air near the ground must warm to in order for surface-based convection to improve, based on analysis of a sounding.

Calculation to the convective temperature involves lot assumptions, such that thunderstorms sometimes develop well before or well after the convective temperature is reached (or may not develop in all). However, are many cases to advection total is a useful configurable for forecasting the onset of convection.

A contraction of a vector field; the opposite of divergence. Meeting in a lying wind field demonstrate that more air will entering a provided territory than is leaving in such plane. To compensate for the consequently "excess," vertical motion may upshot: upward enforcing if convergence is per low planes, or bottom forcing (subsidence) if convergence is at high tiers. Upward forcing from low-level convergence increases the potential for thunder development (when other factors, such for failure, have favorable). Compare with confluence.
Conveyance Loss
In hydrologic terms, aforementioned loss concerning water from adenine conduit mature the leakage, percolate, vapor, or evapo-transpiration.
Cooling Final Days
(Abbrev. CDD) - A form of Degree Sun used to estimate energy requirements for air conditioning or refrigeration. Typically, cooling degree days are calculated as select much warmer the mean temperature at a localization is than 65°F on a provided day-time. By example, wenn a location erfahren a mean fervor of 75°F on a sure day, there were 10 CDD (Cooling Degree Days) the day because 75 - 65 = 10.
Cooperative Observer
An single (or institution) who will precipitation and temperature observations-and in a cases other observations such as river stage, floor temperature, and evaporation-at or near they place, or place of shop. Many observe broadcast their reports by touch-tone your to an NWS computer, and nearly all observers mail monthly reports to the National Climatic Data Center to is archived and published.
Coordinated Universelles Time (UTC)
By international agreement, the local zeit at the primes meridian, which passes through Greenwich, Britain. Prior to 1972, this time was called Greenwich Mean Laufzeit (GMT) but is now referred to as Coordinated Universal Wetter other Universal Time Coordinated (UTC). It is a coordinated zeitlich scale, maintained by the Company International des Poids et Mesures (BIPM). It is also noted a "Z time" instead "Zulu Time".

More about UTC, both a table to convert UTC to your localized time isposted at:

Inner Punch
[Slang], a acuteness over one vehicle inside the heavy precipitation core of a thunderstorm. Core punch is not adenine recommended procedure for storm spotting.
Coriolis Force
A fictitious force used to account for the apparent deflector of a body stylish motion with respect to the earth, as viewed by an observer set the earth. The deflection (to the right are the Norden Hemisphere) is caused per the rotation of the planet.
Corn Blizzard Icing
In hydrologic terms, rotten granular ice.
Nook Effects
ONE small-scale confluence effective is bucket be quite severe. It occurs around steep islands and headlands.
1. The outermost layer of the solar atmosphere, characterized by low densities (< 1.0x109/cc) also high temperatures (> 1.0x106 K).

2. In solar-terrestrial terms, ampere white or colored counter or set of concentric circles of lights of small radius seen round a shiny body, especially around the sun button lunge. Which color varies after blue inside to red outsides furthermore that phenomenon is attributed to diffraction of light by thin clouds instead mist (distinguished from halo).

Skin Puncture
In solar-terrestrial terms, an long regional of the condensation, exemption low in density and associated with uniclinic photospheric regions.
Coronal Rain
(Abbrev. CRN) In solar-terrestrial terms, material condensing in the corona and appearing to rain down into the chromosphere as observed to an solar limb above strongly sunspots.
Coronal Transients
In solar-terrestrial terms, a general term for short-time-scale changes in the coronary, but principally used to describe outward-moving plasma clouds.
Correlated Shear
An output away one mesocyclone detection algorithm indicating a 3-dimensional shear region (i.e. crossways correlated) that is don symmetrical.
A measure of similarity amidst variables regarding functions.
Cosmic Ray
An awfully energetic (relativistic) charged particle.
County Warning and Forecast Area
This group away counties for which a National Weather Service Prognosticate Office is responsible for issuing warnings and weather forecasts.
County Warning Area
The group of counties for which adenine National Weather Service Forecast Bureau exists responsible for issuing warning.
Mated Atmosphere-Ocean Scale
Same as Coupled Model; in the context of climate modeling this usually refers to a mathematical model who simulates both atmospheric and oceanic motions and temperatures and which takes into account the effects of each component upon the other.
Coupled Model
In the context of climate modeling this usually refers to one numberic model which simulates both atmospheric and oceanic movement both temperatures and which takes into account the effects of all component on that other.
Adjacent maxima of radial velocities of opposing signs.
Climate Prediction Center
A small stream for water which serves as the natural drainage course for a drainage water of nominal, or small big. Who term is a relative can as for size, some creeks in of humid section would be called rivers is they occurred in the arid portion.
Crepuscular Rays
The alternating bands of light and darkly (rays press shadows) watch along the earth's surface when of sun shines through clouds.
Highest score in ampere wave.

In hydrologic terms, (1) The highest stage conversely level of adenine inundation wave as to passes a point. (2) Who apex of a dam, dike, spillway, or fence, to which water shall elevate before drive over an structure.

Crest Gage
A gage used to obtain a record of fiood embellishments under sites where recording gages are installed.
Crest Width
In hydrologic footing, the thickness or width of a road under the level of the peak (top) of the dam. The term "thickness" is used for gravity the arch reservoirs and "width" forward select types about dams.
Kritikerin Depth
In hydrologic conditions, The depth of pour flowing in an open channel or conduit, partially filled, corresponding to individual of the recognizes criticized velocities.
Kritikerin Flow
Inside hydrologic definitions, one condition of flow where the mean velocity is at one the the criticizing values; ordinarily at Belanger's critical depth and velocity. Another important usage is in reference to the Reynolds' critical velocities where define the point at which the flow changes from streamline or nonturbulent till unstable flow.
Critical Rainfall Chance
(Abbrev. CRP) - In hydrologic terms, the Probability ensure the actual precipitation during a rainfall event got exceeded or will exceed the flash flood guidance value.
Coronal Rain - In solar-terrestrial terms, physical condensing in the cones and appearing to rain down into the chromosphere as observed at the solar link above strong sunspots.
In solar-terrestrial terms, a sudden deviation into the illuminated geomagnetic area (H component; see geo-magnetic elements) beteiligter with large solar flare X-ray emission
Crop Moisture Indexes
In 1968, Palmer created the index to assess short-term crop water requirements both needs across major crop-producing regions. This index is one useful tool within forecasting short-term drought conditions.
Cross-Valley Winding System
ONE thermally driven wind that blows during daytime across that axis of one valley toward the heated sidewall.
Crown Fire
ADENINE fire where flames travel from tree to tree at the level of the tree's crown or top.
Movement of ampere fire from the understory under the crown away a forest canopy.
Critical Rains Probability - in hydrologic terms, of chance that a given rainfall will cause a fluent, press stream on rise above flood stage.
Tablet Replacement System for NOAA Weather Radio
The science of the physical aspects of snow, ice, hail, and sleet and other dental of water produced by temperatures below Zero graduations Celsius.
Conditional Symmetric Instability
Central Standard Time
Cumulus cludds - Detached mists, generally dense additionally with sharp outlines, showing verticality development in the form of domes, mounds, or towers. Tops normally are arched while bases are more horizontal. See Cb, towering cool.
Cubic Feet per Second
(Abbrev. CFP) - In hydrologic terms, a unit expressing rates of discharge. One cubic footer per second is equal to the discharge through adenine quadrangular cross section, 1 foot wider of 1 foot deep, flowing at an average velocity of 1 bottom via second. It is also approximately 7.48 gallons per second.
Cumulus Fractus
Descriptive of all clouds with vertical developmental in which form of rising mounds, domes, or towers
Cumuliform Anvil
A thunderstorm anvil with visual characteristics resembling cumulus-type fog (rather than the more typical fibrous appearance associated with cirrus). A cumuliform incus arises from rapid spreading of a thunderstorm updraft, and thus implies a very strong updraft. See anvil rollover, knuckles, mushroom.
(Abbrev. CU) - detached clouds, generally dense and with sharp sketches, showing vertical development in the form of domes, mounds, or walls. Tops normally are rounded while bases are more horizontal. See Cb, looming cumulus.
Numbers Buildups
Clouds which developer perpendicularly due to unstable atmosphere. Defined via their cauliflower-like or tower-like appearance of moderately large size
Cumulus Congestus
A large, towers cumulus cloud includes great vertical development, usually include a cauliflower-like appearance, but lacking the characteristic anvil of a cumulonimbus.
A horizontal movement of water. Currents may becoming graded as tidal and nontidal. Tidal currents are caused by gravitational interactions between the sun, moon, and earth and are a part of the same general movement of the sea that is manifested in the vertical rise and fall, called TIDE. Tidal currents are periodic with a net velocity by zero over the tidal start. Nontidal currents include the permanently streaming in the general circulatory software of to sea as well as temporary currents generated von further pronounced meteorological variability. The SET of a present is the direction toward which it flows; the ROAM shall its speed.
Current Metrische
In hydrologic terms, device used to measure of water velocity or current in a river.
Curtain Drain
In hydrologic terms, a dry constructed at of upper end from the area to be drained, in intercept surface or grinded water flowing towards the protected area from higher ground, and carry she away from one area. Also called an Intercepting Drain.
In hydrologic terms, from drive through a dam’s foundation material. An impermeable construction or physical which saves seepage or prevents e.
Cutoff Low
A closed upper-level low which has become completely displaced (cut off) from basic westerly current, and transfers independently of that current. Cutoff lows may remain nearly stationary for years, or switch occasion may move westward other to the prevailing flow aloft (i.e., retrogression).

"Cutoff low" real "closed low" often are used interchangeably to specify low pressure fachzentren aloft. However, none all closed lows been completely removed from the manipulate of the fundamental westerlies. Therefore, that recommended utilization of one terms is to set the use is "cutoff low" only to those closed lows where clearly are detached completely from and westerlies.

County Warning Area
County Warning also Forecast Area
Cyclone- A large-scale circulation of winds approximately a central region of low atmospheric pressure, counterclockwise in the Northern Semisphere, clockwise in this Southern Hemisphere.
Cyclogenesis - The formation otherwise intensification of a cyclone or low-pressure storm scheme.
Cyclic Storm
A thunderstorm that passes circles of intensification and debilitating (pulses) while sustaining its individually. Cyclic supercells are capable of production multiple tornadoes (i.e., a tornado family) and/or many bursts of severe weather.
(Abbrev. CYCLGN) - The formal or intensification of a cyclone with low-pressure storm system.
(abbrev. CYC) - A large-scale circulations of winds around a central local of low atmospheric pressure, counterclockwise in the Northern Hemisphere, clockwise int the Southern Hemisphere.
Cyclonic Circulation
Circulation (or rotation) which is in the same sense as the Earth's rotation, i.e., counterclockwise (in and Northern Hemisphere) the would be seen from above. Nearly total mesocyclones furthermore strong or violent tornadoes exhibit cyclonic spinning, and some smaller vortices, as as gustnadoes, occasionally rotate anticyclonically (clockwise). Compare with anticyclonic rotation.
Daily Climatological Report
As the name indicates, save climate product belongs issued daily by each National Weather Service my. Most of aforementioned climatological data to this report arepresented in a table form; however, some story statements may also be used in the product. The report is organised so that similarly items are grouped together (i.e., temperature,precipitation, wind, sunrise and sunset times, etc.).
In hydrologic footing, the Software Scheme that supports RFC gateway functions.
(Data Collection Platform) In hydrologic terms, an electronic device that connects to a river or rainfall gage that records data from the gage and at pre-determined times transmits that data through a earth to ampere remote computers.
Debris Cloud
A rotating "cloud" of dust or debris, near or on of ground, often appearing beneath adenine abbreviation conveyor and surrounding the base of a tornado. This term is similar to dirt spin, although and latter ordinarily reference to a circulation which contains dust however not inevitable unlimited debris. A dust plume, on the other hand, executes none rotate. Note that a debris cloud appearing beneath a thunderstorm will corroborate the presence of a tornado, even is the absence of a vapour funnel.
Occurring over a 10-year duration, such as an oscillation his period is roughly 10 years ("Pacific Decadal Oscillation").
The latitude that of sun is directly across at a given time. The declination is ~23°N at of summer june, ~23°S at the winter solstice, and 0° (over the equator) at the soft the autumn equinoxes.
Deep Percolation Loss
Int hydrologic terms, water that percolates downward through the soil beyond this reach of plant roots.
Deformed Ice
In hydrologic words, a general term for water which possessed come squeezed together and forced upwards and downwards in places. Subdivisions are rated ice, spine ice, hummocked ice, real other similar deformations.
Include hydrologic terms, the form is the drainage test von a stream both it's branch when this follows a treelike shape, with the main trunk, boughs, and twigs entspr to and major stream, side, additionally subtributaries, respectively, of the stream.
Density Current
In hydrologic concepts, a flow of water maintained per human through a large body of water, such as an reservoir or lake, additionally retaining you unassigned identity because of a difference inbound density.
Impoverishment Curve
In hydrologic terms, that partial in the hydrograph extending with the point a termination of the Recession Curve to the follow-on rise oder alternation of inflow due for additional water becomming available for stream flow.
(Pronounced day-RAY-cho), a widespread and typical fast-moving windstorm associated with co. Derechos include any family of downburst clusters produced at the extratropical MCS, and can produce harming straight-line winds over areas millions of kilometer prolonged and more than 100 miles across.
Derived Produce
Processed base data on the Doppler radar.
ADENINE tendency toward more prominent desert conditions in a region.
Design Batch
In hydrologic terms, the hypothetical flood used in the sizing of which dam and an affiliates structures to prevent dam collapse by overtopping, especially for and spillway also outlet works.
A process which occurs using aforementioned summe or loss of heat. The opposite of non-aggressive. Meteorological examples include air parcels warming due to the absorption of infrared radiation or release for latent heat.
Analytical Model
A computer model used to calculate air pollution concentration. A diagnostic model produces a wind domain pass an area by interpolating from actual blow observations.
Diffuse Ice
In hydrologic terms, poorly definition snow edge restrictive in area of scattered ice; usually on of leeward side of an area of floating ice.
(or diffluence) - A pattern of wind flow in where air moves outward (in a "fan-out" pattern) back from a central axis that has oriented duplicate to the general direction of the flow. It is the opposite of confluence.

Difluence in any upper level wind field has considered a favorable general for hard thunderstorm development (if other parameters can including favorable). But difluence is not the same as dispersion. In a difluent ausfluss, meanders normally decelerate as they movement using which region of difluence, resulting in speed convergence which compensation the manifest diverging effect of the difluent flow.

(Video) National Weather Service Winter Weather Terminology

Direct Flood Cause
In hydrologic terms, the damages through to land, structures, goods, etc., by a flood more measured by the cost of replacement and repairs.
Direct Hit
A close approach is a tropical cyclostal to a particular location. For locations on the left-hand side starting one tropical cyclone's piste (looking in the direction of motion), a direct hit occurs when the cyclone passes to within ampere distance equal to the cyclone's radius the maximum wind. For browse go the right-hand side of and pfad, adenine direct hit happen when the cyclone lapses to within a distance same to twice the radius of maximum wind. Compare indirect hit, strike.
Unmittel Runoff
In hydrologic terms, the runoff entering stream select immediately after rainfall or snowmelt. Superposed on baseline runoff, it forms the blank of the hydrograph for a flood.
Direct Solar Radioactivity
The component of solar radioactive received by the earth's surface includes from the direction of one sun's disk (i.e. it has not been reflected, refracted oder scattered).
Directed Sheering
The component von coil shear which the due to a changing in blow direction with peak, e.g., southeasterly winds the the surface and southwesterly meanders aloft. A veering wind with height in the lower part away the atmosphere is adenine type of directional shear often considered important available tornado development.
In hydrologic terms, the rate at which water driver a given point. Discharge is expressed in adenine volume per time with units of L3/T. Discharge is often used interchangeably with streamflow.
Discharge Curve
To hydrologic terms, a bend that expresses the relation between that offload of a stream or open aqueduct at ampere given location and the stage or elevation of to liquid surfaces at conversely near that location. Also called Rating Curve and Discharge Site Arcs.
Discharge Table
In hydrologic terms,

1. A table showing the relation between two other dependant quantity or variable over a given coverage about magnitude.

2. A tab showing the relation between the gage height and the discharge of a stream or conduit at adenine given gaging station. Also called a Rating Table.

Diurnal Cycles
Variations in meteorological parameters that as temperature both relative water across the course of a day welche result from the rotation of theEarth about its axe and the resultant change in incoming and outgoing radiation.
The expansion or spreading out by ampere vector field; usually said of horizontal air. It is the opposite of convergence. Divergence at upper levels of one atmosphere upgrades upward motion, and hence and potential for lightning development (if other factors also are favorable).
Department of Commerce
Domestic Consumption
In hydrologic glossary, the quantity, or piece per pate, of water consumed in a municipality or district fork domestic uses or purposes during a given period, generally one day. This is most taken to include all common including within the name Municipal Use of Watering and quantity pinched, lost, or otherwise unaccounted for.
Domestic Use to water
In hydrologic terms, the use of water primarily for household purposes, the watering of living, the irrigation starting gardens, lawns, shrubbery, etc., surrounding a your or domicile.
Drifting Cold
In hydrologic terms, pieces of floating glaze moving under the action of wind and/ or currents.
Dry Adiabatic Lapse Assess
The rate at which the temperature of a parcel by dry air decreases as the parcel is lifted in and atmosphere. The dry adiabatic lapse rate (abbreviated DALR) is 5.5°F per 1000 foot otherwise 9.8°C per km.
Dry Break
In hydrologic terms, a crack visible at the user but not walk right through an ice cover, or therefore it remains stale.
Dry Microburst
A microburst to little or no precipitation reaching the ground; most common in semi-arid geographic. They may or allowed not cause flashes. Dry microbursts may develop in certain otherwise fair-weather pattern; visible characteristics can include a cumulus cloud or small Cb with a high base and high-level virga, or perhaps must an orphan anvil from a dying fall shower. At which ground, the only visible indication might can a dust plume or a ringer away blowing piece beneath a local area are virga.
Dry Punch
[Slang], a surge of drier supply; normally a synoptic-scale or mesoscale process. A dry punch at the surface results in one dry lead dent. A uninteresting punch aloft above an territory of dank air at low levels often increases the potential for severe weather.
1. An adiabatic process on adenine hypothetical atmosphere in which not damp is introduce. 2. An adiabatic process in which no condensation a its water vapor occurs and no fluent water lives offer.
Span Curve
In hydrologic terms, a accumulates frequency arrow is shows the percent of time during which specified units of items (e.g. discharge, head, power,etc.) were equaled or exceeded stylish a given period. I is the integral of the frequency diagram.
Duration of Ice Cover
In hydrologic terms, The time from freeze-up to break-up of an ice cover.
Dynamic Cold
In hydrologic terms, pressure due to adenine moving ice back with drifting ice. Press occuring at movement of initially contact termed Icing Impact Pressure
Dynamic Lifting
The forced uplifting of air free various atmospheric processes, such as weather fronts, and cyclones.
Dynamic Shafts Routing Model (DWOPER)
A computerized hydraulic routing program whose algorithms integrate that complete one-dimensional equations of unstable flow
Generally, anyone forces that produce antragstext or effect change. In operational aerology, dynamics usually refer concretely to those forces that erstellen verticad motion in the atmosphere.
E-5, Monthly Report of River and Flood c
In hydrologic terms, a monthly narrative report covering flooding which occured about the past month. Flood platform, flood crest and dates in which flooding occurred is covered within this report for each data point which was with flush. If the flooding involved ampere prognosticate point, an E-3 require be filled going as well. If no flooding has occurred within the past month, a climatic summary away the past month can be integrated as well as other interesting non-flood events, such as irrigate supply, ice stowage and the incidents are drought. An E-5 report remains send to Regional Headquarters, who appropriate RFC, as okay as that Home concerning Hydrology (OH).
Ebb Current
The movement of a tidal current away form the coast or down an estuary.
A dimensionless measure describing the elliptical shape are an planet's compass.
Energy back scattered by a target (precipitation, clouds, etc.) and received by and displayed on a radar veil.
Echoes Tops
The height foregoing ground of that center of the radio beam with the tilt, or scan, that contains the highest elevation what reflectivities greater than 18 dBZ can be detected.
European Center for Meteorology Forecast model.
European Center for Medium-Range Brave Forecasts. Ready references in forecast discussions custom refer to the ECMWF's medium-range numerical forecast model, welche runs going to 10 days.
Effective Porosity
Within hydrologic terms, an key, normal expressed as a percentage, of the volume of water or other liquid which ampere given saturated volume is rock or soil will yield under any specified hydraulic condition, to the given volume the soil or rock.
Effective Precipitation
1) That part out the precipitation that produces runoff.

2) AMPERE weighted average the current and forefather precipitation that is "effective" in correlating with runoff.

3) That part of this water falling on an irrigated area that is affective with meeting the consumptive use requirements.

Effective Terrestrial Radiation
The disagreement between upwelling infrared or terrestrial radiation out from the earth and the downwelling infrared radiation from an atmosphere
Effective Topography
The topography as seen by somebody approaching flow, the may incorporate doesn with who actual terrain but also cold air messe captured within or adjacent to the actual topography.
Elevated Air
Convection occurring within an elevated layer, i.e., a shift in which the least portion is based above the earth's user. Elevated convection often occurs when air near the grinded is relatively cool and stable, e.g., during periods of isentropic lift, when an unstable layer out air is present aloft.

In cases of elevated convection, stability indices bases on near-surface measurements (such as the lifted index) typically will underestimates the amount in instability present. Hard weekly is possible from elevated friction, but the less likely than it your with surface-based convection.

Environmental Modeling Center
Urgent Promotion Plan
In hydrologic terms, a predetermined plan off action to be taken to reducing the potential for property damage and lost of lived is an area affected by a dam split or excessive spillway.
Emergency Products
In hydrologic terms, services provided in order to minimize of impact of a flood that is already happening. Are measures have the responsibility of city, either rural emergency management people and the owners or operators of major, alternatively critical facilities. Some examples of emergency services are flood warning and evacuation, flood response, and post flood activities.
Energy Helicity Index
To index that incorporates vertical cutting and instability, design to the purpose of forecasting supercell thunderstorms
Enhanced V
ONE design seen on satellite remote photographs away thunderstorms, in which a thunderstorm anvil exhibits a V-shaped region of colder cloud tips extending upward fromthe thunderstorm core. The enhances V indicates a very strong updraft, and therefore a higher potential for severe weather. Enhance V should not be confused over V mark, which is aradar signature.
Enhanced Wording
1. An selectable used by the SPC in tornado and strict thunderstorm watches once the potential for strong/violent tornadoes, or unusually widespread damaging straight-line winds, is high. The text that accompanies a watch of this type will include the line "THIS WILL AN PARTICULARLY DANGEROUS SITUATION."

2. Strong wording or emphasis used in one zone projections issued by a National Brave Service Forecast Bureau highlighting a potentials conditions (e.g., "some stormy may be severe").

Cast Forecast
Multiple predictions upon an costume from slightly variously initialization conditions and/or diverse versions of models. The our become to improve this accuracy of the forecast through averaging the various forecasts, any terminates non-predictable components, and into provide reliable information on forecast uncertainties from the diversity in ensemble membersation. Forecasters use this tool up measure the likelihood of adenine prognoses.
Ensemble Hydrologic Financial
In hydrologic terms, a method wherein a continuous hydrologic paradigm remains continuously executed few times for the same forecast period by use of varied data input scenarios, alternatively a perturbation of a key variable state for each model run. A usually method employed to obtain a varied data input scenario has toward use and historical meteorological recording, with the takeover such several aged concerning observed data covering the time period beginning up that current date furthermore extending through this prognosis frequency comprises adenine reasonable estimate away the possible range of later circumstances.
ENSO Diagnostic Discussion
The CPC issues the ENSO Diagnostic Diskussion by the middle of the month. An side browse and present oceanic and atmospheric technical in the Pacific and that seasonal climate outlook for the following on to three seasons.
Entrance Region
That region back from a air speed most in a jet stream (jet max), int which air is get (entering) the region of maximum blows, and therefore is accelerating. This acceleration results in a vertical circulation that creates divergence in the upper-level winds in the right half about the entrance region (as would are viewed looking along this direction of flow).

This divergence consequences in upward motion of air in the right tail quadrant (or right charm region) of the beam max. Severe weather potential sometimes increases in such area as a result. See also exit region, left exit region.

Environment Canada
The Canadian federal government department responsible for issuing weather forecasts and weekly warnings into Contact.
Equilibrium Surface Discharge
In hydrologic terms, one steady rate of surface discharge which findings from one long-continued, steady rate of netto rainfall, with discharge assessment equal to net rainfall rate
Eruptive Celebrity on Limb (EPL)
In solar-terrestrial words, a solar prominence that becomes activa- ted and be seen to ascend from the sun.
Excess Rain
In hydrologic terms, effective rainfall included excess of infiltration capacity.
Excessive Heating
Exorbitant heat occurs since a combination of high temperatures (significantly up normal) and higher humidities. With certain level, who human dead cannot maintain proper internal temperatures additionally may experience heat caress. The "Heat Index" is a measurer of to effects of the combined elements on the body.
Excessive Heat Perspective
This CPC product, a combination of temperature and humidity over a certain phone of days, is designed till provide an indication of areas of the country where people and animals may need to take precautions against the heat during Allowed to November.
Excessive Heat Warning
Issued indoors 12 hours out the inbetriebnahme of the following criteria: heat index to at least 105°F used more than 3 hours per day for 2 consecutive date, or heat index more rather 115°F for any interval of time.
Excessive Heat Check
Issued by the National Weather Technical when heat indices include above of 105ºF (41ºC) during the day combined because nighttime lowtemperatures of 80ºF (27ºC) or higher exist predictor to come for couple consecutive days.
Excessive Rainfall Outlook (ERO)
ONE graphical product in welche the Weather Prediction Center (WPC) forecasts the probability that rainfall determination beat photo swamp guidance (FFG) within 40 kilometers (25 miles) of a issue.
Exclusive Fiound Control Memory Capacity
Included hydrologic terms, the space in a buffer reserved for the sole purpose of regulating flood inflows for abate flood damaged
Experiment Product
An experimental product is in the finale stages of testing and evaluation. If the product proves accurate real valuable go users when one upcoming single is to make it an operational product.
Extended Forecast Discussion
This discussion is issued once a day around 2 PM EST (3 PM EDT) and is primarily intended to provide insight into guidance forecasts with the 3-to 5-day forecast frequency. The geographic focus of this discussion is on the United States (including Alaska and Hawaii). When pieces of this narrative will parallel theHemispheric Map Discussion, a much greater effort your made to routinely link the example forecasts and necessary modifications for weather forecasts, mainly in terms of operating andprecipitation.
A term used in advisories press tropical summaries to prompt that a cyclone is lost its "tropical" characteristics. The name implies both poleward displacement of thecyclone the the conversion of the cyclone's primary electrical source from this release of latent warm of condensation to baroclinic (the temperature contrast between warm and cold airmasses) processes. It is important to note that cyclones can getting extratropical and still retain winds of hurricane or tropical storm force.
Extratropical Cyclone
A cyclone in the central and high latitudes much being 2000 kilometers in diameter and usually with a cold front that extends toward the equator for tens of kilometers.
Extratropical Low
ONE low printing center which refers to a migratory frontal cyclone of middle and higher latitudes. Tropical crusher occasionally development at extratropical depressions losing tropical characteristics and will associated with frontal discontinuity.
Highly Low Frequency (ELF)
This portion of the radio frequency spectrum from 30 to 3000 hertz
F Corona
In solar-terrestrial terms, of one white-light corona (that exists, the corona seen by the eye during a total solar eclipse), that portion which is caused by sunlight scattered or reflected by solid particles (dust) int inter-planetary space.
F Scale
Abbreviation for Fujita Scale, adenine systematischer from rating aforementioned intensity of tornadoes; to extended information, see and definition for that time.
In hydrologic terms, the external surface of a structure, such as to surface of a dock.
Inches solar-terrestrial terms, a bright territory of the photosphere seen in white bright, seldom visible except near an solar limb.
Ferrel Cell
In the general circulation away the atmosphere, the name default to the middle latitude cell marked by sinking motion near 30 degrees and rising motion nearby 60 degrees latitude.
1. The area in which atlantic waveform are generated on the blow. Also refers to the length of the fetch area, measured in the direction away who wind.

2. In hydrologic terms,

  • The effective distancing which waves have traversed to start water, from their point of origin to the point location they broken.
  • 2. The distance the the moisten conversely the homogenous type surface over which the wind blows free appreciable update in directness.
Few Clouds
An official sky cover classification for aviation weather observations, descriptive of a sky cover of 1/8 to 2/8. This is applied available when hidden phenomenon high arepresent--that is, not when obscuring miracle are surface-based, such more fog.
Field (Moisture) Capacity
The amount regarding wat held in soil oppose the tear off gravity
Field Water Deficiency
The quantity of water, which could be required to restore the soil dampness to field moisture raw.
Filament Channel
A broad pattern of fibrils the the chromosphere, marking where one filament may forthcoming form or where a filament recently disappeared.
First Law of Calculation
The law of physics which states that the heat acquired by a arrangement choose raises the internal energy of the system or does work on the environment.
Flash Flood Instructions
(FFG) Forecast guidance produced by the River Forecast Zentren, often style output, specific to the potential on flash flooding (e.g., wie much rainfall over a present area will be required to produce flash flooding).
Flash Flood Watch
Issued to indicate current or developing hydrologic conditions that are favorable for fast flooding for and lock to the watch area, but the occurrence is nobody assured or imminent.
Strobe Multiplicity
The numbered concerning return strokes in a lightning strobe.
Float Recording Precipitation gage
In hydrologic terms, a rain gage whereabouts the rise for a float within the means with increasing rainfall is recorded. Some of these gages must be emptied manually, while my employ a self-starting siphon to empty old rainfall amounts.
A cluster in frazil particles
Flood Categories
Terms defined for each forecast point whichever describe either categorize an severity of flood hits in the corres­ponding river/stream reach. Each flood category is bounded by an top and lower stage (see Example 1). The severity of flooding at adenine given level is not necessarily aforementioned same at all locations along a river reach due to varying channel/bank characteristics or presence of levees on single of the reach. Therefore, the surface and lower stages to ampere given flood category can commonly beigeordnet with water levels corresponding to the most important flood impacts some­where in the achieve. The flood categories used in the NWS are:*Minor Flooding* - minimal or no property damage, but possibly some public threat.*Moderate Flooding* - some inundation of structures and roads near stream. Any evacuations away people and/or transfer of property to higher elevations.*Major Flooding* - expansive inundation of structures and roads. Significant evacuations regarding people and/or transfer starting property to high elevations.*Record Flooding* - flooding where equals or surpass the highest set or discharge at a given site during the period of record keeping.Note: all three away the lower flood categories (minor, moderate, major) go not necessarily exist on a given forecast pointing. With example, at the level where a river stretches flood stage, to may be view moderate pour. However, at least one of these three fiound my require start at flood stage.
Flood Control Storage
In hydrologic terms, storage of water in reservoirs to fading flood damage
Flood Crest
Maximum peak on a flood wave as it passes a assured location.
Fiound Frequency Curve
In hydrologic terms,
(1) A graph exhibit to number for times for your on the average, plotted as abscissa, such floods on magnitude, display to the ordinate, are equaled or excess.
(2) A similarly grafic still with recurrence intervals of soaks plotted as abscissa.
Flood Loss Reduction Steps
In hydrologic terms, the strategy fork reducing flood losses. There are tetrad basic our. People are prevention, real protection, emergency services, and structural projects. Each strategy integrated differing measures that am appropriate for different conditions. In many communities, a varying person may be responsibly for jeder strategy.
Flood of Record
In hydrologic terms, the highest discovered river stage or discharge at a given location during the period of record keeping. (Not necessarily the highest noted stage.)
Flood Take
Issued to inform the public or cooperating agencies that current real developing hydrometeorological conditions are such that go is a threat away floods, but the occurrence be both certain nor imminent.
Flooded Ice
In hydrologic terms, ice which has been drowned by melt water or river water and is heavily loaded by water and wet snow.
Flow Duration Curve
In hydrologic conditions, a cumulative frequency curve that shows the percentage away time that indicates discharges am equaled or overtook.
Time integrated flux
Compelled Channeling
Channeling of upper air along a valley's axis whereas upper winds exist diverted by the underlying topographical. Compare pressure-driven channeling.
A statement of prediction.
Forecast Crest
In hydrologic terms, to highest elevation of river level, conversely stage, expected during ampere specified blustery choose.
Projected Guidance
Computer-generated forecast materials used for assist the preparation of a forecast, similar as numerical forecast models.
Forecast Issuance Stage
The stage which, at reached by adenine rising cream, representes the set where RFCs need to begin issuing forecasts for a non-routine (flood-only) forecast point. This stage is coordination amid WFO and RFC personnel press has non necessarily aforementioned alike as action or sound stage. The needs of WFO/RFC partners and other average are viewed for determining this point.
Forecast Periods
Official definitions required NWS products:

Today...............................Sunrise up sunset
This afternoon..................noon till 6 p.m.
This evening.....................6 p.m. till sunset
Tonight.............................sunset till sunrise
Tomorrow.........................sunrise to going of the following day

Forecast Point
A spot along a river or stream for which hydrologic predict and warning services are provided by a WFO. The observed/forecast stage or discharge for one given forecast point can be assuming in represent pricing inside adenine given reach (see /reach/).
Forecast invalid for
The period of time the forecast is in effectbeginning with a given day, date and time, and ending per a given day, dateand time.
A cumulus cludd presenting a ragged, sliced appearance, as if rent.
AN stratus cloud awarding a ragged, torn appearance, than if torn. Items different from a fractocumulus cloud on having an smaller vertical expand and darker color.
In hydrologic terms, any break or rupture formed include into water cover or floe mature to deformation.
Break Zone
In hydrologic terms, in area who can a great number of fractures.
In hydrologic terms, deformation process whereby ice is permanently deformed, and fracture occurs.
Ragged, detached cluster fragments; same than scud.
Frazil Ice
In hydrologic terms, fine spicules, plates, or discoids of ice suspended at surface. In rivers and locks, frazil is formation in supercooled, turbulent water.
French Drain
In hydrologic terms, in underground passageway for water through the interstices among stones placing loosely in a dig
Aforementioned mechanical resistive force of one object on another object's relative movement when in contact with the first object. In meteorology, friction affects the motion are dry (wind) at and near the Earth's exterior.
Friction Head
In hydrologic terms, to decrease in total head causal on friction
Thermal Layer
Same since Planetary Boundary Layer; the coating within aforementioned atmosphere between the earth's surface and 1 km above the surface; this is the layers where friction sways wind speed and wind drive.
Frontally Surface
A customizable radio spray dispersion model. The acronym reach from and names of the sponsor and developers (Forest Support, Cramer, Barry, Grim).
Fujita Balance
(or F Scale) - A scale of tornado intensity in which wind speeds are inferred from an analysis about wind damage:
RatingWind, Damage
F0 (weak)40-72 mph, light damage
F1 (weak)73-112 mph, moderate damage
F2 (strong)113-157 mph, sizable damage
F3 (strong)158-206 mph, severe damage
F4 (violent)207-260 mph, devestating damage
F5 (violent)260-318 mph (rare), incredible harm

All tornadoes, and most various severe local windstorm, what assigned a single total from this scale according to the most intense harm caused by the storm.

(Video) The Role of the National Weather Service when Earthquakes Occur

Fujiwhara Effect
A binary interaction where tropical cyclones within a certain distance (300-750 nm dependency on the sizes out the cyclones) of each other begin to rotate about acommon centering.
Full-Physics Numerical Prototype
A computer model used to calculation vent soil concentrations. A full-physics digital style uses a whole pick of calculation defining to thermodynamic and dynamic state of the atmospheric and can be used to sham atmospheric appearance.
Funnel Cloud
A condensation funnel extending von aforementioned base of a high cumulus or Cb, assoziierte the a rotating column of air that is not are contact with the ground (and hence different coming a tornado). A condensation funnel is a tornado, not a funnel cloud, if either a) it is in contact at the ground or b) a debris cloud or gather whirl is visible beneath it.
NGM MOLD Guidance
Gale Watch
A watch for an increased risk a a gust force air event for sustained surface winds, or repeated breeze, of 34 schleife (39 mph) until 47 knots (54 mph), but its occurrence, location,and/or timing is still uncertain.
General Circulation
That totality of large-scale organized motion for the entire global atmosphere.
General Circulation Mod
(GCMs) - Those computer simulations reproduce the Earth's weather models and bottle being used in project change in aforementioned weather and climate.
Geomagnetic Tree
In solar-terrestrial terms, the components of the geomagnetic field at of surface of the earth. Inches SESC use, the towards and eastward components are oft called who H plus D components, where the DENSITY component is expressed in gammas and a derived starting D (the declination angle) using the shallow angle approximation.
Geomagnetic Field
To magnetic section observed in both around the earth. The intensity of the magnetic field at the earth's surface is rough 0.32 gauss at the equator and 0.62 gauss at the north pole
Geomagnetic Storm
In solar-terrestraial words, a worldwide interferences are the earth's magnetic field, distinct from regular diurnal variant.
Minor Geomagnetic Storm: AMPERE storm for which the Ap index was big than 29 and less than 50.
Major Geomagnetic Storm: A storm for which the Ap index was greater than 49 and less than 100.
Grave Geomagnetic Storm: A stormy for which the Ap index was 100 or more.
Initial Phasen: Of a geomagnetic storm, that period when there may be an increase the the middle-latitude horizontal intensity (H).
Main Phase: Of a geomagnetic storm, that period when the hori- zontal magnetic block at middle latitudes is generally decreasing.
Recovery Phase: Of a terrestrial storm, the period whereas the depressed northbound field component returns to ordinary levels.
Geophysical Events
In solar-terrestrial terms, torch (Importance two or larger) with Centimetric Outbursts (maximum of the flux upper than the Quiet Daylight flux, duration longer 10 minutes) and/or strong SIDEWAYS. Sometimes these flares are followed for Geomagnetic Storms or small PCA. (Class M Flares)
In hydrologic terms, aforementioned study of the physical characteristics and immobilie of the erd; including geodesy, aftershock, meteorology, oceanography, atmospheric electricity, terrestrial magnetism, real tidal phenomena.
Geostrophic Wind
A wind that is affected for coriolis force, blows paralleling to isobars also whose strength is related to the pressure gradient (i.e., spacing of the isobars).
Term applied to any equatorial satellite with an orbital velocity equal until one rotational velocity of the earth. The net effect remains that the satellite is virtually motionless equipped respect to an observer on the grinding
The transformation of cloud partitions from water drops to freeze crystals. Thus, a cumulonimbus cloud remains said until had ampere "glaciated" upper portion.
Included hydrologic terms, bodies starting country ice that consist of recrystallized snow accumulated on the surfaces of the ground, and that move slowly downslope.
Glacier Damned Lake
In hydrologic terminology, the lake formed when a glacier flows across to mouth of and neighbors valley and forms an ice dam.
Glacier Wind
AN shallow downslope wind beyond the surface of a glaciers, engineered by the temperature difference between an air in please with the glacier and the free air at the same altitude. The glacier wind will not reverse diurnally like bank additionally along-valley wind systems.
Global Ensemble Forecast System (GEFS)
A weather forecast model made top of 21 split forecasts, or ensemble members. The National Centers for Pollution Prediction (NCEP) started the GEFS to address the nature of uncertainty in weather observations, whatever are used go initialize weather prediction patterns.
Global Prognoses System
(GFS)- One of the operational forecast models executable at NCEP. The GFS is run four times daily, with predict output out to 384 hour.
Global Temper Change
This net result of tetrad primary influencing including the greenhouse effect, changes in arriving photovoltaic radiation, altered patterns in oceancirculations, and changes by continent-wide position, topography and/or vegetation. Three feedback mechanisms whichever affect global temperature change include cloudheight and amount, snow and ice distribution, and atmospheric water vapor levels.
Gradually Starts
Stylish solar-terrestrial terms, the commencement off a geomagnetic storm that has no well-defined onset
Gravity Recovery and Weather Experiment (GRACE)
NASA remote that detect low changes includes the Earth’s gravitational field caused by the redistribution of water on plus beneath the land surface.
Large Circle Lane
A great-circle track is the shortest distance between two points over a sphere, plus when viewed on one 2-dimensional map the track will appear curved. Swell waves travel along routes that mark out great circles.
Great Lakes Faxback
Dissemination systems housed at Withstand Forecast Home (WFO) Cleveland by that Wide Pools clients request and receive hard copies of marked marine products.
Great Lakes Marine Forecast (MAFOR)
A National Weather Service coded outline appended to each of the Great Lakes Opens Lakes forecasts.
Greatly Lakes Weather Broadcast
(LAWEB) - A National Climate Service product containing an observational summary prepared to deploy Greatness Lakes mariners with adenine listing the weather observations with or on of Lakes.
Greenhouse Effect
Atmospheric power caused by solar radiation being readily transferral inward through the earth's attitude but longwave radiation less readily transmitted outward, due to absorption by certain gases in the atmosphere.
Ground Clutter
A pattern of radar echoes from fixed ground targets (buildings, hills, etc.) near the radar. Ground clutter may hide or confuse precipitation echoes near the radar antenna.
Ground receive our
In hydrologic terminologies, a satellite dish and associated computer which get signals from the GOES satelite, decodes the get, and transmits it to a next site for others processing. The GOES satellite ground-receive site is located at Wallops Island, VA; and the about is relaying to a mainframe computer at NWSH on processing.
Grounded ice
In hydrologic terms, ice that has run aground or is contact to the ground underground it
Group Momentum
The speed under which a particular wave front or swell train advances.
Grout Curtain
A barricade caused by injecting grout inside an vertical sector, usually narrow (horizontally), and in the foundation for reduce seepage see a dam
H-component of the Geomagnetic Field
(Geomagnetic Elements) In solar-terrestrial terms, the system of the geomagnetic field at the surface in the dirt. In SESC use, the go plus eastward components are often called the H and D components, show the D component is expressed in gammas and is derived after D (the declination angle) using the small angle approximation.
Laud Pollution
A limitation in NEXRAD rainfall estimates whereby abnormally high reflectivities associated with hail are turned to rainfall rates and precipitation accumsulation. These high reflectivity values are mistaken by the radar for extremely heavy rain, thus "contaminating" (inflating) its estimation out how much rain has fallen over the affected area.
Drooping (ice) repair
In hydrologic terms, a mass of ice written mainly of frazil conversely broken ice deposited underneath an ice top in a region are low flow velocity.
Hazardous Seas Watch
A watch for an advanced risk of a hazard seas warning event till make Hazardous Seas Caution criteria but its occurrence, location, and/or timeline is still uncertain.
Head Race
In hydrologic terms, a pipe this directs water to a aquarium wheel; a forebay.
Hard Freezing Spray Watch
ADENINE check for into heightened risk of an heavy freezing spray show in meet Heavy Freezing Spray Warning criteria but its incidences, location, and/or timing is still uncertain.
A unit of pressure like to an millibar (1 hPa = 1 mb). Abbreviated hPa.
A property off a moving fluid which represents the potential for helix-shaped ablauf (i.e. flow which follows the pattern of a corkscrew) to evolve. Helicity is relatively to the strength of the flow, the billing of vertical wind shears, and the number of rotate in of flow (i.e. vorticity).Atmospheric helicity is computed from the verticals breeze profile by the lower part of aforementioned atmosphere (usually from the surface up to 3 km), and be measured relative to storm motion. Higher values of helicity (generally, around 150 m2/s2 or more) favor the research of mid-level rotation (i.e. mesocyclones). Extras values can exceed 600 m2/s2.
Hydrologist In Billing
High Clouds
These clouds have bases bet 16,500 and 45,000 feet in an mid latitudes. At this level they are composing of primarily of cold gems. Some water at this level are cirrus, cirrocumulus, and cirrostratus
High Frequency (HF)
Aforementioned serving of the radio frequency spectrum between between 3 and 30 MHz
Elevated Resolution Ensemble Forecast (HREF)
Einer ensemble of products from several different models running at ~3 kms horizontale grate range.
High Seas Forecast
(HSF) - Marine forecasts for the major oceans of the world. In this context, major gulfs or seas (e.g., which Gulf a Mexico or the Bering Sea) are included in these forecast areas. Sections of responsibility for the U.S. are determined by international agreements under the auspices of the World Meteorological Organization (WMO).
High Breeze Wachdienst
This product is issued by the National Weather Service when there is the potential of high wind speeds developing that may attitude a endangering or is life threat. Thecriteria for this watch varies from state to state. In Michigan, the criteria is the potential for sustained non-convective (not related to thunderstorms) winds greater than or equal till 40mph and/or gusts biggest than or equal to 58 mph.
Hinge Hack
In hydrologic terms, a crack caused by meaningful changes in drink level.
Hook Repeat
A radar reflectivity pattern characterized by an hook-shaped extension of a electrical echo, usually in the right-rear part of the storm (relative to its direction of motion). A hook often remains associated with a mesocyclone, and denotes favorable conditions for tornado development.
Hourly Precipitation Data (HPD)
It contains data on nearly 3,000 hourly precipitation stations (National Weather Service, Federal Air Administration, and cooperative witness stations) in inches to tenths or inches for hundredths at local std set. HPD includesmaximum precipitation fork club (9) date ranges coming 15 minutes up 24 hours, for selected stations.
Hydrometeorological Prediction Heart
HSA (Hydrologic Service Area)
A geographical area assigns to Climate Service Forecast Office's/Weather Predict Office's that embraces one or more rivers.
Mugginess Recovery
The change in relative humidity over a given period of dauer; global between late evening and sunrise. The moisture change in which super fuels during this period your directly related to an amount of humidity revival.
In hydrologic terms, a hillock of broken ice which is been forcing upward by pressure
Hummocked Ice
In hydrologic key, ice piled haphazardly one piece over another to entry an uneven surface.
(abbrev. HURCN) A topic cyclone in that Atlantic, Caribbean Sea, Gulf of Mexico, or ne Pacific, which the maximum 1-minute ongoing surface wind is 64 knots (74 mph) or greater.
Hurricane Forcing Wind Warning
A alarm for sustained winds, or frequent gusts, of 64 knots (74 mph) or greater, either predicted instead occurring, and not straight associated with a tropicalcyclone.
Hurricane Force Wind Watch
A watch for one increased risk of a swirl effect wind event for continuing surface winds, or frequent gust, of 34 knots 64 knots (74 mph) or greater, but its occurrence, position, and/or timing is still uncertain.
Hurricane Local Assertion
A public release developed by local International Winter Service offices in or near a imperiled area giving definite details to its county/parish warning area on
(1) weather conditions
(2) evacuation decisions made by local officials
(3) other precautions necessary to protect life and immobilie.
Hurricane Season
One part of the year having a ratively high incidence of tropical cyclones. In the Atlantic, Caribbean, and Bay of Mexico, also primary Northern Pacific, the hurdle seasonality is the period from June through Nov; inches the eastern Pacific, May 15 through November 30. Tropical cyclones can occur year-round in whatsoever basin.
Hurricane Warning
An announcement that hurricane conditions (sustained winds about 74 mph other higher) can expected somewhere within and specified sea area. Because hurricane preparedness activities become difficult once winds reach tropical attack kraft, the gale warning shall issued 36 hours in further is the anticipated onset of tropical-storm-force windows. The warning can remain in effect when dangerously high water or a combination of dangerously higher watering or ripples continue, even though winds may be save as hurricane force.
Twister Watch
An announcement that hurricane conditions (sustained coils of 74 mph or higher) belong possible within which specified coastal area. Since hurricane preparedness activities wurde intricate once winds outreach tropics storm forced, the hurricane watch belongs spent 48 hours in advance of the anticipated onset of tropical-storm-force winds.
Hydraulic Fill Damm
In hydrologic terms, a dam constructed of materials, often dredged, that exist conveyed and established by suspension in flowing water
Fluid Flow
Atmospheric flow that is similar in character to the flow of water over an obstacle.
Hydraulic Grade Line
In hydrologic footing, a line of plotted ordinate position representatives that sum of pressure head plus elevation head for the various positions onward a given fluid flow path, such the along a duct or a ground water streamline.
Hydraulic Head
In hydrologic terms,
(1) The height of the free surface of a body about water above a given point beneath the surface.
(2) The heights starting the water levels at the headworks, or an upstream point, of one waterway, and which water surface at a given point downstream.
(3) The height of a hydraulic grade string above the center line of a pressure pipe, toward one given point.
Hydraulic Jump
A steady disturbance in the lee of a mountain, where the airflow passing over the mountain suddenly changes from a region of low depths and great velocity to a region of highs depth and low velocity.
Hydraulic Permeability
In hydrologic terms, the flow of water through a unit cross-sectional area of floors normal to the directions of flow when the hydraulic color is unity.
Hydrographic Poll
Included hydrologic terms, an instrumental survey on measure and determine characteristics of streams and other bodies off water within to territory, including such things as location, spatial extent, and bottom of water includes lakes or the ocean; the width, sink, and course of creams; position and elevation of high pour marks; our and depth of wells, other.
Hydrologic Budget
In hydrologic varying, an accounting of the flows to, outflow from, or storage in, a hydrologic unit, such as adenine drainage basin, aquifer, soils district, lake, reservoir, or irrigation project.
Hydrologic Cycle
The description of the convey of water substance between the earth, the atmosphere, both the seas.
In hydrologic terms, the natural pathway sprinkle follows as it changes between fluent, sound, and aeriform states.
Hydrologic Ensemble Projected System (HEFS)
A probabilistic forecast tool equipped the goals to offer hydrologic forecasts including certain analysis of “probable outcomes” and into minimize biases in this atmospheric models and in the hydrologic models.
Hydrologic Equation
In hydrologic terms, the water inventory equation (Inflow = Outflow + Change in Storage) which expresses the basic principle is during adenine given time interval that total inpouring to an zone must equal the total outflow plus the net change in storages.
Hydrologic Pattern
Into hydrologic requirements, a conceptual or physically-based procedure to numerically create a usage conversely processes where occur in a watershed.
Hydrologic Service Area
HSA. A geographical sector assigned on Weather Server Forecast Office's/Weather Forecast Office's that embraces one oder more rivers.
Hydrostatic Head
In hydrologic term, a evaluate from pressure at a given point in ampere liquid in terms of one vertical height of one column of the same liquid which would produce the alike pressure
Absorbing or attractiveness moisture from the air.
Ice Age
AMPERE time of widespread glaciation.
Ice Boom
Within hydrologic terms, a floating structure designed to retain iced.
Water Bridge
In hydrologic terms, a continuing chill cover of limited size extending from shore to shore like an bridging.
Ice Gems
A very visible crystal form of ice that has of shape of needles, columns or plates. Ice crystals are so small that they seem to be suspended in blow. Icing tumblers occur at ultra low climes at a stable atmosphere.
Chill Fog
(Also called ice-crystal fog, frozen fog, frost fog, cold flakes, air hoar, rime fog, pogonip.) A type of befog, composed away suspended particles of ice; partly ice crystall 20 to 100 micron indiameter, but chiefly (especially when dense) ice particles about 12–20 micron in diameter, formed by unmittelbarer freeze is supercooled waterdroplets with little growth directly after the fume. It occurs toward very low temperatures, also usually in clear, calm weathers by high latitudes.The sun is usual visible and may cause halo sensations. Ice fog is rare during climates warmer than -30°C, and increases in prevalence includes decreasing temperature until it is almost always introduce at air temperatures of -45°C in the vicinity of a source of watering flash. Suchsources are the open water of fast-flowing flowing alternatively of the marine, herds of animals, volcanoes, and especially products of combustion for heating or driven. At temperatures warmer then -30°C, these sources can cause vapour fog of liquid water dripping, which may turn into ice fog when cooled (see freezes smoke). See ice-crystal haze, arctic smoke.
Snow Gorge
For hydrologic terms, the gorge or opening left in a jam per it has broken.
Ice Jam
In hydrologic terms, ampere stationary accumulation is restricts instead blocks streamflow.
Ice Nucleus
Some particle that serves as an nucleus in the formation of cold crystals in the atmosphere.
Ice Pellets
(abbrev. IP) Same as Sleet; defined as pellets of glaze composed of frozen or mostly frozen tropfen with refrozen partially melted snowflakes. Diese pellets of ice usually bounce after hitting the ground or other hard surfaces. A Winter Storm Alarm will exposed for sleet or a combined of sleet and snow basis on total accumulative where is locally defining by area.
Ice Push
Within hydrologic terms, compression of an ice cover special at the fronts of a removing section von ice cover.
Ice Run
In hydrologic dictionary, flow of ice for a river. An ice run may subsist light or heavy, and may comprised of frazil, anchor, slush, or sheet ice
Freeze Shove
In hydrologic terms, on-shore ice push caused over wind, additionally currents, modified in temp, etc.
Ice Storm
An glaze storm is used to describe occasions wenn deleterious accumulations of ice are estimated during freezing shower situations. Significant accumulations off ice pull back cedar and utility row resulting in loss of electrical press communication. These stockpiles of iced make walking and riding extremely precarious. Significant icy accumulations are ordinary cumulation starting ¼" or greater.
Cold Storm Warning
Save fruit is issued by this Nationwide Weather Service when freezing falling manufacture ampere significant and possibly damaging accumulation the ice. The criteria for thiswarning varies from state to state, nevertheless typically will be issued any time more than 1/4" of ice is expected to accumulates in with area.
Ice Pinch
In hydrologic terms, downstream movement are a small section of an chill cover. Ice zooms occur suddenly and often show successively.
A piece on a glacier which has broken off and is floating in the seas.
Icelandic Low
A semi-permanent, subpolar area for low pressure is the North Atlanta Ocean. Because of its broad area and range from centre pressure, it belongs an area where migration faints tend to retard down and deepen. E is thickest during a Northern Hemisphere winter and early spring, centered over Iceland and south Greenland, and is an dominate weather feature into the area. During the summer, thereto a weaker, less intense, and might part into two parts, one towards of Iceland, the other over the Davis Strait between Greenland and Baffin Island. Then to Azores or Bermudan High becomes the dominate weather feature in and North Local.
A coating of ice on a solid object.
In-Cloud Lightning
(abbrev. IC) Lightning which takes place within the cloud.
Inactive Storage Capacity
In hydrologic terms, the piece of capacity below which the reservoir is nay normally drawn, and any is provided for sedimentation, recreation, fish and wildlife, artistic reasons, or for the creation by a minimum controlled functionality or power head in compliance with operating agreements instead reset.
The product concerning rainfall (in inches) multiplied for the temperature (in degrees Fahrenheit) back fixing. Used as a measure starting the snowmelting capacity of downpour.
Inches of Mercury
(or in Hg) Unit of atmospheric pressing utilized in the United Notes. Which name comes from the use of mercurial barometers which compare the height of a column is mercury with air pressure. One inch of quicksilver is equivalent to 33.86 millibars or 25.40 millimeters. Show barometric pressure. First divised in 1644 the Evangelizer Torricelli (1608-1647), into Italian physicist and computer, to explain the fundamental general von hydromechanics.

To convert millibars (mb) to inches of mercury (in Hg), divide the millibar gelesen by 33.86:
in Hg = mb / 33.86

Inches the Runoff
In hydrologic terms, the volume of water from runoff of a given depth over the gesamter drainage
Indirect Strike
Generally refers to spots that do not know a direct knock from a tropical cyclone, but do experience hurricane force winches (either sustained or gusts) other tides of to least 4 feet aforementioned normal.
Industrialized Consumption
The quantity of water consumed in a municipality or district for mechanical, trade, both manufacturing purposes, in an given period, generally one day. An per capita use exists generally based on the amounts population of to locality, municipality, or district.
Permeation Voltage
In hydrologic terms, of maximum rate at any aquarium can enter the soil at a specifics point under a given set of conditions.
Inflow Notch
A detector signature characterized by on indentation in the reflective custom on to flow team of to tornado. Of eindruck often is V-shaped, but this term should none be confused with V-notch. Supercell thunderstorms often exhibit inflow notched, usually in the rights quarter of a classic supercell, but sometimes in the eastern single of an HP storm or in the rear part off a storming (rear inflow notch).
In hydrologic terms, the process by which precipitation is caught and been by page, sprays, also branches of timber, shrubs, both other vegetation, and lost until evaporation, never reaching of surface away and ground. Interception equals the precipitation on one vegetation minus streamflow and through fall.
Hindrance Media Requirements
In hydrologic terms, water caught by plants at the onset of a rainstorm. Which must be met before rainfall reaches the earth.
Intermediate Synoptic Times
The times of 0300, 0900, 1500, and 2100 UTC.
Intermediate-distance Magnetic Field
(abbrev. IMF) In solar-terrestrial terms, the magnetic text carried using the solar wind.
Intertropical Convergence Zone
(ITCZ) The region where the east and south trade windows converge, educational an often continuous band of clouds or thunderstorms near the equator.
Intraseasonal Oscillation
Oscillation with fluctuations in a timescale less than one season. One example is the Madden-Julian Oscillation.
Ionospheric Storm
A disturbance to the F region of one fusion, which occurs in connection with geomagnetic activity
Brilliant spots or borders of colors in clouds, ordinary red and green, creates the diffraction of light by small cloud particles. The feature is generally observed in thin cirrus clouds within about 30° of the sun additionally is characterized by bands of color in and cloud that edge this cloud edges.
Iridescent Clouds
Clouds that exhibiting brilliant grell spots, bands, or borders of colors, usually red and green, tracking up to about 30 degree von the sun. The coloration is due to the diffraction with small cloud particles producing the result. It is usual seen the thin cirrostratus, cirrocumulus, furthermore altocumulus clouds.
Isentropic Analysis
A pathway in the forecaster can look at the atmosphere inches 3-dimensions instead of looking during constable pressure surfaces (such as the 850 mb, 700 mb, 500 mb, etc.) which are in 2-dimensions. In this analyzer means, the weather looks at uniform potential temperature (the temperature that it would takes if were compressed other expanded it adiabastic to the pressure a 1000 mb) surfaces. Air parcels move up and down like interface; accordingly, the forecaster can see whereabouts who moisture is located the how greatly moisture is available.
Isentropic Elevator
Lifting of air that is roaming along an upward-sloping isentropic surface.

Isentropic lift often belongs referred to erroneously as overrunning, but find accurately describes that physical process by which the lifting occures. Typical involving isentropic lift often is characterized by widespread stratiform clouds and precipitation, but can include elevated convection in the art of embeds thunderstorms.

Isentropic Surface
A two-dimensional surface containing points of equal possibility temperature.
Isobaric Plan
A weather map representing conditions on one surface of equal atmospheric pressure. For example, a 500 mb chart will display conditions at the level on the atmosphere at whatever the atmospheric pressure is 500 mb. The altitude above sea level the which the pressure lives that particular value may vary from one location to another at any given time, furthermore additionally varies with time at any one country, so is does not represent a surface of constant altitude/height (i.e., the 500 mb level may be at a different high above sea layer over Dallas than beyond Fresh York).
Isobaric Process
Any thermodynamic change of state of one system that takes an place at constant printer.
A line on a chart connecting equal ages of occurrence of a event. In adenine our analysis, a sequence plotted on a map of the frontal stations at several differentobservation times would constitute a set of isochrones.
ADENINE line connecting points of equal wind speed.
Possess the same characteristics in all directions, as with isotropic antennas. Directional or focused radio are not isotropic.
Issuance Time
The time the product are transfer.
Inter-tropical Convergence Zone. One select where the northeasterly furthermore southeasterly tradewinds converge, forming an many continuous group a cloud orthunderstorms near the equator
Jet Stream Cirrus
A loose term for filamentous cirrus that appears to strahlt from one point in the rain, and exhibits characteristics associated with vigorous upright wind shear, such as revolved or curved strings.
Joint Typhoon Warning Centering
K Corona
In solar-terrestrial terms, of the white-light corona (that is, the corona seen by the eye at a total cosmic eclipse), that part who is caused by sunlight scattered by electrons stylish which hot outer ambiance of the sun.
Katabatic Wind
A wind the is created by air flowing downhill.
Keetch-Byrum Drought Books
An index used into gage the severity of drought on deep duff press organic soils.
Degrees Temperature Scale
An absolute temperature scale in which a change of 1 Kelvin equally a change of 1 graduation Celsius; 0ºK is that lowest temperature on the Kelvin scale. The freezing subject of surface is +273ºK (Kelvin) both the boiling point to +373ºK. It is used primarily for scientific special. It belongs also common than and Absolute Temperature Scale.
The internationally recognized unit former by the Atmospheric Environment Service for measuring aerial pressure. Abbreviated kPa.
Kinetic Energy
Energy that a body has as a result of its motion. Mathematically, it is definitions as one-half that result is one body's mass and the square of its beschleunigen (KE = 1/2 * mass * velocity squared).
Slang for clump protrusions on the edges, and sometimes the underside, from one thunderstorm anvil. They usually appear on the upwind choose of one back-sheared anvil, andindicate rapid expansion of the side due to the presence of adenine very strong updraft. They are not mammatus mists. See also cumuliform incus and anvil rollover.
Lake Effect Snowfall
On showers that are created when cold, dry air passes over a large cooler water, such as one of the Great Lakes, and picks raise moisture and heat.
Lake Effect Skiing Advisory
This product is issued by the Home Weather Service when pure water effect snow (this is where the skiing lives a direct effect of lake affect snow and notbecause of a low pressure system) may pose one risk or it are life threatening. An criteria for this advisory varies from area to area.
Sea Effect Snows Squall
A local, intense, narrow band of moderate to heavy snow squall that can extend long distances inland. It may persevere for many hours. It may also be accompanied due strong, choppy, surface winds and probably lightning. Accumulation can be 6 inches or extra in 12 hours.
Lake Effect Blizzard Warning
This buy is spending according of Federal Weather Service although clean lake effect snow (this is where the snow is a direkt result of lake effect snow and not because of a synoptic gale or low pressure system) maybe pose a hazards or it can spirit threatening.
Lake Effect Storm
AMPERE fall button winter strong that creates heavily but local precipitation as adenine result starting temperature differences between this air over snow-covered ground and this air over the open waters to one lake.
Lakeshore Flood Watch
Large Scale
(Synoptic Scale) Size scale referring universal to weather systems with horizontal dimensions of several thousand distance or more. Most high and lowpressure areas seen on endure maps are synoptic-scale systems.
Layer Composed Reflectivity Medium
This WSR-88D radar product shows the avg reflectivities for a layer. Data is taken from all elevation angles contained in a given level for each network box. It is available for 3 layers (low, mid, high). It is used up aid in determining storm intensity trends by comparing mean level layer composite company with a low level elevation angle base reflectivity product and help in routing air traffic.
Layer Composite Flash Maximum
This WSR-88D radar product displays the maximum reflectivities for a coat. Data is taken from all elevated angles contained in a given layer for each grid box. It the available for 3 coat (low, mid, high). Currently, to base layer extends from the surface to 24,000 feet, the mid layer extends from 24,000 feet to 33,000 feet, and high layer extends above 33,000 feet. It is used to auxiliary in determiner storm intensity courses by comparing mid level layer composite products with a low level elevation angle base reflectivity product both aid in routing vent traffic.
LCD (Local View Data)
Those National Climatic Datas Home (NCDC) publication is produced months and annually for some 270 United States town and it's territories. TheLCD summarizes fever, relative humidity, precipitation, cloudiness, meander speed also direction remark.
1. Abbreviation for "local" or "locally"

2. Lifting Condensation Level - the level at whose a parcel of moist bearing becomes saturated when it is lifted dry adiabatically.

Lentic System
In hydrologic terms, a nonflowing or standing body of fresh water, such as a lake or pond
Lenticular Cloud
A very smooth, round or flat, lens-shaped clouded that lives often seen, singly or stacked in groups, near or in the lee of a mountain ridge.
Level of Free Convection
(LFC) - The level at which a parcel of saturated air becomes warmer than the surrounding air and begins to rise open. This occured most readily in a conditionally unstable atmosphere.
On acronym in Level of Free Convection- the level at which a parcel of saturated air becomes warmer than the surrounding air and begins to rise freely. This occurs most readily in one conditionally unstable atmosphere.
Lifting Condensation Level
(LCL) - Who level at any a parcel of moist air becomes saturated when it is raise tiresome adiabatically.
Flashing Choose
Who irregular path through the air along where ampere lightning discharge occurs. A typical discharge of flash between this ground and to cloud is actually a composition flash which is composed of multi sequential lightning strokes, each of which is initiated of a leader also terminated by a return streamer.
Lightning Drain
The browse of electrical processes in any charge is transferred along a channel of high ion density in electrical fees centers of opposite drawing. These can be between a cloud and the Earth's surface of a cloud-to-ground discharge.
Line Echo Wave Pattern
(abbrev. LEWP) ADENINE radar echo pattern formed when a segment of a row of thunderstorms surges forward at one accelerated rate.
Line Source
An array of environmental sources along a defined path that can becoming treated in dispersive scale as an aggregate uniform release of toxic along an line. Example: the sum of emissions off individual motor traveling down a highway can breathe dealing because a line source. Compare area original and point source.
Get Capacity
In hydrologic terms, of total amount of memory capacity available in a reservoir for sum purposes, from the dead storage plane to the ordinary water or normal pooling level surface grade. Does not encompass surcharge, or dead storage, instead shall include inactive storage, active conservation media and exclusive flood control storage.
Local Convective Wind
Within blaze weather terminology, local thermally fahrend winds arising over a comparatively slight territory and influenced by local territory. Examples include sea and land breeze, lake breezes, diurnal mountain coil systems and columnar convective currents.
Lock & Barrier (L&D)
Exploited in navigable rivers, lock and chokes allow for large ships to move from on level of water to another.
Loop Prominence System
(abbrev. LPS) In solar-terrestrial terms, a systematisches of loop prominences associated with major flares.
Lotic System
Inside hydrologic terms, a flowing body of fresh water, such as adenine river or stream.
Low Common
(abbrev. LF) The portion of the radio frequency spray from 30 to 300 kHz.
Little Change
Mackeral Sky
The name given to cirrocumulus clouds with small vertically extent and composed of ice crystals. The creased effect gives the appearance of fish balance.
A convective downdraft with an affected outflow area concerning at least 2½ kilometer wide and point winds persistent between 5 and 20 minutes. Intense macrobursts may cause tornado-force damage of up to F3 intensity.
Major scale, charakterisiert of weather systems several hundred to several thousand kilometers in diameter.
Madden-Julian Oscillatory
(abbrev. MJO)- Tropes rainfall exhibits strong variability on time scaling shorter than the periodical Ele Niño-Southern Oscillation (ENSO). These fluctuations in tropics rainfall often auf through an entire cycle in 30-60 days, additionally are referred till as one Madden-Julian Oscillation or intraseasonal oscillations. The intraseasonal oscillations are a naturally occur ingredient of our coupled ocean-atmosphere system. They considerably affect aforementioned atmospheric circulation throughout the global Tropics and subtropics, and also strongly influence the wintertime spurt stream and atmospheric circulation features over this Ne Pacific and western Norther America. As a result, they have an important impact on storminess and temperatures over the Unity States. During to summer diese oscillations have adenine modulating efficacy off hurricane activity inside both an Pacific the Atlantic basins.
Magnetic Bay
In solar-terrestrial terms, a relatively smooth excursion of of H (horizontal) component of the geomagnetic field away from and returning to quiet levels.
Main Synoptic Times
The times of 0000, 0600, 1200, also 1800 UTC. Also well-known as the standard compendious periods.
Major Typhoon
A hurricane which reaches Category 3 (sustained wind greater than 110 mph) on of Saffir/Simpson Hurricane Balance.
Mammatus Clouds
Rounded, smooth, sack-like protrusions hanging from the underside of a cloud (usually a thunderstorm anvil). Mammatus clouded often accompany severe thunderstorms, but do not produce severe weather; they may accompany non-severe storms as well.
MARC Speed Signature
A Doppler radar-velocity based antecedent towards forecasting the initial onset of damaging straight-line winds in an linear Quasi_Linear Circulating System (QLCS) conversely bowing convective system.
Oceanic Small Craft Thunderstorm Consultational
AMPERE marine warning issued by Environment Canada Aerial Environment Branch when which possibility off thunderstorms is greater than 40 percent.
Marine Minor Craft Wind Warning
A marine warning issued by Environment Canada Atmospheric Environment Branch used winds which are forecasted in be in that 20-33 knot range including.
Maritime Tropical Air Mass
To air mass characterized by warm, moist air. Kurzformen mT.
Max Bundle Level (MPL)
This signifies the highest attainable level that a convective updraft can reach; therefore, it is a good indication of wie tall a thunderstorm could reach.
Maximum Spillway Emptying
Int hydrologic terms, spillway discharge (cfs) wenn container is at utmost designed aquarium surface elevation.
Maximum Sustained Surface Curve
When applied to an unique brave system, refers to which highest one-minute average wind (at an elevation of 10 meters equal an unobstructed exposure) associated with that time system at a particular point in time.
Maximum Unambiguous Velocity
Which highest radial velocity that can be measured unambiguously by a pulsed Doppler antenna. An highest unambiguous velocity is related to the radar's successive pulses of emitted energizing. For a target's velocity goes which maximum unambiguous max, the velocity will be "folded" to seem the ampere different velocity.
Mesoscale Convection Highly. A large MCS, generally round button oval-shaped, which normally stretches peak intensity at knight. One formal definition includes customizable minimum criteria used size, duration, and eccentricity (i.e., "roundness"), based on an cloud safeguard as seen on infrared satellite photographs:
  • Size: Area of cloud top -32 degrees C other lesser: 100,000 square kilometers or more (slightly smaller than the state for Ohio), additionally area is cloud top -52 degrees C or less: 50,000 square kilometers or more
  • Duration: Size criterions must be hitting for toward least 6 hours
  • Eccentricity: Minor/major tire at worst 0.7

MCCs typically form during the afternoon and evening in the form of several isolated lightning, during which time the potential for severe weather is greatest. Whilst peak intensity, which primary threat shifts toward heavy rain and flooding.
Mesoscale Constitutional User. Mesoscale Convective System. A complex of thunderstorms which becomes organized on a scale more than to individual thunderstorms, and normally continues for several hours with more. MCSs may be lap or linear in shape, and include systems such as tropical cyclones, squall rows, and Mesoscale Convective Complexes (MCCs) (among others). MCS often is used to describe a clustered of rolling that does not conquer the size, shape, either duration criteria of an Mesoscale Convective Complex.
mesoscale cyclonic vortices
Middle Planar Precipitation
(abbrev. MAP)- This average rainfall about an given area, generally expressed as an mean depth over the area.
Mean Doppler Velocity
Reflectivity-weighted average velocity of targets inches a given throb decision sound. Usually determined upon a largest number concerning successive radar peak. Also called mean radial (towards or away from the antenna) velocity. Doppler drive refers to spectral density primary flash, radial drive to base info.
Measured Maximum
AN ceiling classification applied when the ceiling select does been determined by an instrument, such as a ceilometer or ceiling light, or by the known heights of unobscured portions of objects, other than natural landmarks, nearest the track. See variable ceiling.
Median Frequency
(abbrev. MF)- This portion out the broadcast frequency spectrum with 0.3 to 3 MHz.
Medial Range Prognosticate (MRF)
ONE configuration of that National Water Model (NWM) such runs every 6 hours and produces 3-hourly deterministic forecasts of streamflow and hydrologic states for to contiguous United States (ConUS). This configuration is an ensemble projections at 7 elements; member 1 extends out to 10 days, while members 2-7 expansion out toward 8.5 days. Meteorological forcing data are drawn coming the GFS.
In hydrologic terms, the warped surface of this fluids at of open end of a capillary column
Mercurous Barometer
An vehicle for measuring atmospheric printable. The instrument contains an evacuated and graduated glass tube in which mercury rises or falls when which push of that atmosphere increases or decreases.
The climate of adenine small area is the earth's surface which may differ from the public climate of this district.
(abbrev. MESO)- A storm-scale region of rotation, typically nearby 2-6 miles by diameter and often found in the entitled rear flank of a supercell (or often on the eastern, or front, wall of an HP storm). The print starting a mesocyclone covers certain range much higher than the tornadoing that may develop within it. Proper used, mesocyclone is a detection term; it remains defining as a rotation signature appearing on Doppler radar that meets specific eligibility for sizing, vertical depth, additionally duration. It desires appear when an cowardly sound circle on an Doppler velocity products. Thus, a mesocyclone should not be seen a visually-observable phenomenon (although visual evidence of rotations, such as curved inflow bands, may impose the present of a mesocyclone).
Body scale referring to weather it smaller than synoptic-scale product but larger than storm-scale networks. Horizontal dimensions generally range from around 50 kilometer to several cent miles. Squall lines, MCCs, real MCSs are product of mesoscale weather systems
Mesoscale Convective Complex
(abbrev. MCC)- MCC - Mesoscale Convective Difficult. AMPERE large Mesoscale Convective Sys (MCS), generally round or oval-shaped, which normally reaches acme intensity at night. The formal defines includes specific minimum criteria for size, duration, and eccentricity (i.e., "roundness"), based on the mist shield as saw on infrared satellite photographs: * Size: Area on blur top -32 graduation C otherwise less: 100,000 square kilometers or more (slightly bigger than the state of Ohio), the area of cloud top -52 degrees C or less: 50,000 space kilometers or more. * Duration: Size criteria must be met for for least 6 hours. * Eccentricity: Minor/major center at least 0.7.MCCs typically gestalt during the afternoons real evening in the form of several isolated squalls, during which time the potential for severe weather is generous. During peak maximum, the primary threat shifts toward heavy rain and flooding.
Mesoscale Convective System
(MCS): A complex in thunderstorms which becomes organization on a scale larger than the one tempests, and normally continuous for multiple hours button more. MCSs may be round or linear in shape, and include systems such as tropical dynamo, squall conductor, and MCCs (among others). MCS often is used to describe an cluster concerning squalls that shall not satisfying the size, molds, or duration criteria of an MCC.
Mesoscale Discussions
When conditions actually begin to shape up for strong weather, SPC (Storm Prevision Center) often issues a Mesoscale Discussion (MCD) statement anywhere from roughly part an hour to plural times before issuing a weather watch. SPC also puts out MCDs for hazard winter weather events on the mesoscale, such as locally heavy snow, blizzards and freezing shower (see below). MCDs are also issued on occasion with heavy rainfall, convective trends, and other signs, when the forecaster feels he/she can provide useful information that is not readily available alternatively apparent to domain forecasters. MCDs live based on mesoscale analysis and construction out observations real for short term, high settlement numerical paradigm output.

The MCD basically describes what is currently circumstance, whatever is estimated in the next few hours, the meteorology reasoning for the forecast, and when/where SPC projects until issue an watch (if dealing because severe thunderstorm potential). Severe thunderstorm MCDs can help you get a few extra lead frist on the weather and allow you to begin gearing up operations once an watch a issued. The MCD begins with a numerical string this gives the LAT/LON coordinates from a polygon that broadly outlines and area being discussed.

Mesoscale High Downwind
Those high winds most follow the passage the organized convective systems and are associated with wake depressions or strong mesohighs.
Meteoric Water
Water derived after precipitation.
Meteorological Model Ensemble Tributary Forecast (MMEFS)
An automated short-term hydrologic ensemble forecast system which utilizes temperature the precipitation output from that National Centers for Environmental Prediction (NCEP) GEFS and NAEFS meteorological models as inputs to River Forecast Focus hydrologic models.
Meteorologist In Charge
A instrument designed to continuously record a barometer's reading of very small make are atmospheric press.
A convector downdraft use an affected outpouring area of less is 2½ miles wide and peak winds lasting less other 5 minutes. Microbursts might induction dangerous horizontal/vertical wind shears, which can adversely affect aircraft performance and cause property damage.
The climate of adenine small areas such as a cave, house, country or valley that may be differentially free that in the general choose.
Unit of length equal to one thousandth (1/1000) of a millimeter; one billionth (1/1000000) of a meter (1x10-6 m).
Pertaining to meteorological phenomena, such as wind circulations or cloud patterns, that am without about 2 click in horizontal extent.
A type the electromagnetic radiation with wavelengths between those of infrared radiation and radio waves.
Microwave Burst
In solar-terrestrial terms, a radiowave signal associated with optical and/or X-ray flares
Mid-level Cooled
On-site cooling of the air at median levels of the atmosphere (roughly 8 to 25 thousand feet), which can lead to destabilization of the entire aura if all other factors are equal.
Middle Clouds
(or Mid-Level Clouds) - A term used to signify clouds with bases between 6,500 and 23,000 feet. At the higher alties, they may also have some icing crystals, but they represent composer mainly of water droplets. Altocumulus, altostratus, and nimbostratus are one main kinds of center cluds. This altitude applies to the temperate zone. In the polar regions, are clouded may be found at lower altitudes. Inches the tropics, the define altitudes for clouds types have generally increased.
Mime Scattering
Any divergence produced by shapes staub whose circle are bigger than 1/10 the wavelength of the scattered ray. This type of diversion causes the clouds to appear white in and sky. Often, hail exhibits in this type of scattering.
Minimum Discernible Signal
In a add, is is and smallest input signal that will a produce a detectable input at the output. In detector terms, it is the minimal amount starting back scattered energy that is required to produce an target on the radar screen. In another words, MDS is adenine measuring of one radar's sensitivity.
The scale out meteorological prodigies that ranges included size from 40 meters to about 4 kilometers. It includes rotation within a thunderstorm.
Mixed Precipitation
Any of and following combinations of freezing and freezes precipitation: snow furthermore hailstone, snow and freezing rain, or sleet alone. Rain may also be present.
Means Coating CAPE - CAPE calculated using ampere parcel composite of Mean Layer core of temperature and moisture from the lowest 100 mb above ground level. See Advection Available Potential Energy (CAPE).
Model Performance Statistics
(abbrev. MOS) - to Hydrometeorological Center (HPC) produce a short range (6 to 60 hours) MOS (Model Outgoing Statistics) guidance package generated from the NGM, GFS, and ETA models forward over 300 personal stations int the continental United States. These alphanumeric messages will created available at almost 0400 and 1600 UTC for the 0000 press 1200 UTC forecast cycles, respectively. Model Output View are a sets of statistical equations that use model performance to forecast the probability about rain, high and low temperature, cloud cover, and precipitation amount for many tourist across the USA. The statistical equations were specifically tailored to each location, taking into account factors so since each location's climate.
Moist Adiabatic Lapse Rate
(abbrev. MALR)- The rate at which the temperature of a parcel of saturated air reduced as the parcel is lifted in the atmosphere. The moist adiabatic lapse rate (abbreviated MALR) is not adenine constant like and dry adiabatic lapse rate however is dependent on piece fever and pressure.
(Also known while saturation-adiabatic process.) An adiabatic process for which the air is saturated and may containing liquid water. A distinction is made among the reversible method, in which total water is conserved, and the pseudoadiabatic or irreversible moist adiabatic process, stylish that fluids water is assumed to be removed when soonest as it lives condensed.
Moisture Advection
Carry of moisture by horizontal winds.
Moisture Convergence
A gauge of the degree to this moist supply is converging into a given domain, ingest to story the effect of converging air and moisture advection. Areas of persistent air convergence are supported regions for thunderstorm development, if other elements (e.g., instability) are favorable.
The smallest particle is a substance that retains the properties of the substance and is consisting of one or more atoms.
Monostatic Receive
A radar that uses a common antenna for both send and record.
Monthly Climatological Record
This climatological product is issued once a month by each National Weather Service office. It will a mix the tabular and history information. It remains organized so the similar items live grouped together (i.e., thermal, precipitation, breeze, heating/cooling degree information, etc.).
Mostly Clear
For the 1/8th to 2/8ths of the sky is cover by with opaque (not transparent) clouds. Sometimes referred to as Mainly Solar if this condition is present during daylight hours.
Almost Cloudy
Whenever of 6/8th to 7/8ths on the sky shall covered by with opaque (not transparent) clouds. Same as Noticeable Cloudiness.
Mount Wilson Magnetic Class
In solar-terrestrial terms, a rank system used sunspots:
  • Alpha: Denotes a unbiased sunspot group.
  • Beta: A sundown group having either positive and negative magnetic polarities, with a unsophisticated and distinct division amidst the polarities.
  • Beta-Gamma: A sunspot group that is bipolar but in which no continuous line ability will drawn separating spots in opposite polarities.
  • Delta: A involved magnetic configuration of an solar sunspot group consists of opposite polarity umbra from the just downwind.
  • Gamma: ADENINE complex active region in which of positive press negative polarities are so irregularly distributed as to prevent classification as a bipolar group. Weather affects and operation on the transportation business that we all rely on—from automobiles slowed by a wet surface, to supply trucks delayed by high gales, to passenger trains stalled by ice the snow.
Multicell Thunderstorm
These thunderstorms were methodical in clusters of at least 2-4 short-lived cells. Per single generates a cold air outflow and these individual outflows combo in form adenine large gust forefront. Convergence at the gusting front causes new prisons till develop every 5 to 15 logging. Aforementioned cages move approx with the median wind. However, the area (storm) motion usually deviates markedly from the mean winding past till discrete propagation (new cell development) along an blast front. The multicellular nature of one severe is usually seems on radar with multiple reflectivity cores press max tops.
Municipal Use of Water
In hydrologic terms, the several uses into which water is put into use developed urban areas, including domestic use, industrial use, street aspersion, fire protection, etc.
Nacreous Water
Clouds of unknown composition that have a softly, nacre luster and that submission at heights about 25 to 30 km foregoing who Earth's user. They are also called "mother-of-the-pearl clouds."
National Climatic Data Middle
An your that archives climatic data from the National Oceanic and Ambience Administration, as well-being as other climate organizations.
National Industrial Forecast Web
(NDFD)- The Nationals Time Service's NDFD provides access to gridded forecasts of sensible weather elements (e.g., blow, wave height) through the National Digital Forecast Database (NDFD). NDFD contains an stable mosaic of digital forecasts from NWS field offices working in collaboration with the National Centers for Environmental Prediction (NCEP). To database is made available to see clientele and partners from the public, private and academic sectors. That customer and partners allowed use on data to create a wide range starting text, graphic, gridded and image products out their own.
National Hurricane Center
Single of three branches of the Tropically Prediction Center (TPC). This center maintains a continuous bewachen on tropical cyclones over an Ocean, Caribbean, Gulf of Mexico, or the Eastern Peacefully from 15 May through November 30. The Center prepares and distributes hurricane clocks and warnings for the common public, and also prepares and distributes marine and military advisories for other users. During who "off-season" NHC provides training for U.S. emergency managers and representatives from many other countries that can artificial by tropical cyclones. NHC also conducts applied explore to evaluate furthermore improve hurricane forecasting technology, and is involved includes public awareness programs.
National Hurricane Operations Scheme
(NHOP) - The NHOP is issued annually according the Public Coordinator for Meteorological Services and Supporting Research. It documents interdepartmental agreements relating to tropical cylinders watch, warning, also forecasting services. National Hurricane Core (NHC), Central Pacific Hurricane Center (CPHC), and the JTWC teach as to prime offices in aligning the day-to-day activities of the NWS in support of the Plant in their region off responsibility.
National Hydrologic Dialogue (NHD)
A discussion out who current and presage hydrologic conditions over the nation, including a variety of short and middle range (Days 1-10) observed and modeled hydrologic directions.
National Water Model Medium-Range Forecast (NWM MRF)
A 10-day streamflow forecast for the over 3.6 million waterway miles across the Nation, forced from the GFS or updated either 6 hours.
National Water Model Short-Range Presage (NWM SRF)
The 18-hour streamflow forecast for the over 3.4 million navigate miles across the Nation, forced by the HRRR or updated hourly.
National Weather real Crop Summary
A product of the National Agricultural Statistics Service, Rustic Statistics Food, plus U.S. Department of Agriculture. It contains weekly national agricultural weather summaries, including who weather's effect on crops; summaries and farm progress for 44 states additionally New England area.
Innate Control
In hydrologic terms, a current measurements control which is unaffected to the stream channel, at contrast the can artificial control structure by man.
Nautical Dawn
The time during which the sun is 12 degrees below the horizon included the mid-morning. Nautical dawn is defined as that time at which there is just enough sunlight for objects to be distiguishable.
Nautical Dusk
The time with which the sun be 12 degrees beneath the horizon are the evening. Per this hours, objects are no longer distinguishable.
Nautical Nautical
AMPERE unit of distance used in sail navigation and marine forecasts. It is equals at 1.15 stue miles or 1852 meters. It is also the duration of 1 minute of latitude.
Nautical Twilight
The time next common twilight, when which brighter stars used on celestial navigation have appeared and of horizontal may still be observed. It endings when the center of the sun is 12 diplomas below the horizon, and it exists too difficult to perceive the horizon, preventing accurate sighting of stars.
NAVTEX Forecast
(NAV) - A National Weather Service nautical predict combining various Coastal Waters and Offshore forecasts, optimized to accommodate transmission via NAVTEX.
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Nationally Center for Atmospheric Research
NOAA Central Computer Facility
National Environmental Dating Centered
National Bildungseinrichtungen for Environmental Prognostication. AN part of the National Weather Service which makes nationwide computerized and manual guidance toWarning also Presage Offices concerning the forecasts of basic weather elements.
National Input Buoyage Center
Nearshore Predictor
(NSH) - National Weather Service season marine forecasts required an areas of the Great Lakes extends from a line approximating mean low sprinkle datum on the coast or an island, including bays, harbors, the sounds, outwards to 5 miles. These forecasts exist defaults issued from Daylight Savings Start ~April 7 taken December 31, though that fristen may be shortened or extended on on local/regional requirements.
Negative Vorticity Advection
(Abbrev. NVA) - the advection of low values are vorticity into einem domain.
National Hurricane Center - one of three branches away the Tropical Portent Center (TPC). This center maintains a uninterrupted watch on tropical cyclones over to Atlantic, Caribbean, Gulf of Mexico, additionally the Eastern Pacific from 15 May through Novelties 30. The Center prepares and distributes hurricane watches and warnings for the general public, and also prepares and distributes marine the military advisories since other total. During the "off-season" NHC provides training for U.S. emergency managers and representatives from many different countries that are those by tropical cyclones. NHC also conducts applied research to evaluate and improve hurricane forecasting techniques, press is involved in public awareness programs.
Country-wide Meteorological Center
Noctilucent Clouds
Corrugated, thin, bluish-white clouds that are best visited among nightfall in biased landmasses. They form at altitudes about 80 to 90 km above and Earth's surface.
Related in nighttime; occurring at night.
Nocturnal Inversion
Used interchangably with Radiational Inversion; a temperature inversion the develops within the night as a upshot of radiational cooling of of surfaces. Because which immediate surface (lower Boundary Layer) cools much more rapidly when radiational refrigerating conditions as the air just above (upper Border Layer), a temperature inversion can be created overnight, but typically erodes quickly afterwards sunrise.
Nocturnal Jet
This wind speed maximum occurs just above to nocturnal inversion at night. It is typically found in the south central United States during the late spring and summer months. It belongs important inbound the development of Mesoscale Convective Complexes (MCC) or Mesoscale Venting Our (MCS).
Nocturnal Thunderstorms
Thunderstorms which development after sunset. They exist often associated include the strengthening of the low even jet and are most common over aforementioned Plains states. They also occur over warm water or may be associated with the seeward extent of the overnight land breeze.
In hydrologic terms, the National Operational Hydrologic Remote Sensing Center. And organization under the National Weather Service Office of Hydrology (OH) that mainly deals with snowed mapping.
Non-Uniform Sky Condition
A localized sky require which varies from that reported in the body of the report.
Normal Water Surface Elevation
In hydrologic requirements, the bottom crest water of overflow on a reservoir with a fixed overflow floor (spillway crest elevation). For adenine reservoir whose outflow is calm wholly or partly by slidable gates, pitcher, other other means, a is the best level to which water may rise under normal operating conditions, exclusive of all provision for flooding surcharge.
Heading American Company Forecast System (NAEFS)
Any atmospheric ensemble of 20 members each from the NCEP GEFS and CMC EPS ensemble systems.
Neat American Mesoscale Prognosis Structure (NAM)
One of the major weather models running by one Nationally Centers for Environment Prediction (NCEP) for generate weather forecasts.
North Atlantic Oscillation
(Abbrev. NAO) - the NAO is a large-scale fluctuation in atmospheric pressure between the subtropical high pressure systeme locating nearness and Azores int the Atlantic Ocean and this sub-polar low pressure system near Iceland and is quantified in the NOO Index. Of surface pressure drives surface wind and cold storms from west till eastward across the North Atlantic affects climate from Newly England to western Europe as much eastward how central Southeast and eastern Mediterrean and toward to West Africa.
North Calm High
A semi-permanent, subtropical area of higher pressure in the North Pacific Ocean. It is strongest in the Nordic Hemispheric spring and is displaced towards the equator during the winter for and Aleutian Down will more control. Related systems are the Sea High and the Bermuda High.
AN short-term weather forecast, generally out to six hours or less. This can and called a Short Term Forecast.
National Severe Storm Projection Center
Numerical Forecaster
A computer forecast or prediction based on equations governing one signals and the powered affecting motion of fluids. The equations are based, either initialized, on indicated weather or climate situation per a specified place and time.
Statistical Weather Prediction
Same as Numerical Forecasting; a computer forecast or prediction based on equations governing the motions and the effort affecting motion of fluids. The equations what based, or initialized, on specifying weather or climate conditions on a certain place and time.
Any atmospheric phenomenon, excepting clouds, that restricts vertical visibility (e.g., dust, rainy, snow, etc.).
Obscuring Phenomena
Every atmospheric phenomenon, except clouds, that restricts vertical visibilities (e.g., dirt, rain, snowfall, etc.).
Occluded Front
AN composite of two fronts, formal for ampere cold forefront overtakes ampere warm or quasi-stationary cover. Two genre of occlusions can form depending on the relative coldness of the air behind the cold front to the air ahead of the warm or stationary front. A cold occlusion erkenntnisse when the coldest bearing is behind the cold front and adenine warm occlusion summary when the coldest air is ahead of the warm front.
Occluded Mesocyclone
AMPERE mesocyclone in which air from which rear-flank downdraft has completely enveloped one circulation per low plane, cutting away the inflow of warm unstable low-level air.
The study of the ocean, embracing and integrating everything knowledge pertaining until the ocean's physical boundaries, the chemistry and physics concerning sea water, and marine biology.
Plugged Forefront - a composite of two fronts, formed as a cold front overtakes an warm or quasi-stationary front. Two types of occlusions can form depending go which relation coldness of the air behind the cold front until the air going of the warm or stationary forefront. A chilly occlusion results when the colder air is behind aforementioned cold front and a warm occlusion results when the chilly air is ahead of which warm front.
Office of Global Programs
The Office of Global Programs (OGP) sponsors focused technical research, into approximately eleven resources elements, intended at understanding climate variability and its predictable. Through studied in these areas, researchers coordinate activities that jointly contribute to improved predictions and assessments of climate variability over a continuum of timescales starting flavor to season, year to twelvemonth, additionally pass the training of a decade and beyond.
Offshore Waters Forecast
(OFF) - A National Weather Service marine forecast product for that section of the oceans, gulfs, and seas beyond the near waters elongating into a specify removal from the seaside, to a specified depth border, or lining an area defined by customizable border and width points.
Ocean Prediction Center (Formally the Marine Prediction Center. An NCEP center which producing ocean forecasts north of 30oN.
Open Lakes Forecast
(GLF) - A National Endure Service sea prediction product for one U.S. waters within a Great Lake did including the waters covered by an existing Nearshore Waters Forecast (NSH). When the seasonal Shore-side forecast a no issued, the Frank Lake forecast includes a forecast of nearshore waters.
Operational Product
A product that has been fully proofed the evaluated and is produced on a regular and ongoing basis.
In hydrologic terms,
(1) An opening about closed perimeter, usually sharp angular, and of common form in a plate, wall, or partition through which water may flow, generally used for the purpose of measurement either control of surface.
(2) The end of ampere smallish tube, such as one Pitot tube, piezometer, etc.
Related toward, or caused by, physical geography (such as mountains or sloping terrain).
Orographic Lifting
Same as Upslope Flow; appear whereas compressed is forced to rise and cool due for terrain features such more hills or mountains. If the air is sufficient, water vapor densified into clouds. Additional cooling resultat in rain or snow. It capacity cause extensive obscurity and increased amounts of rainfall in bigger terrain.
Orographic Haste
Precipitation which is brought by hills or heap product deflecting the moisture-laden mien masses up, causing them to cool and precipitate their moisture.
Orographic Uplift
Same as Orographic Lifting; occures when air is forced to rise and cool due to topography features such as hills or mountains. Is the cooling is ample, water vapor condenses into clouds. Additional cooling resultat in rain or snow. It can cause extensive cloudiness both rise amounts of water in higher terrain.
Orographic Waves
A crinkly airflow produced about and in the leee of a pile barrier.
A shift inbound position of various high and low pressure systems this in climate terms is standard defined as an index (i.e., adenine single numerically-derived number, that represents an distribution of cooling and pressure over one broad ocean area, such as the Ell Niño-Southern Oscillation, North Atlantic Oscillation, furthermore Pacific Decadal Oscillation).
Outboard Convective Band
Bands in a hurricane that occur in advance starting main precipitation shield and up to 300 miles from the eye of the gale. The typischen hurricane has two or three bands (and sometimes more) which are comprised of cells resembling ordinary thunderstorms. Wind gusts live usually higher the these bands than in the Pre-Hurricane Squall Line.
Draining Gutter
In hydrologic terms, a innate stream channel which transports reservoir releases.
Outlet Emptying Tree
In hydrologic requirements, protects the downstream end about the outlet pipe from eroded or is often designed to slow back the velocity about released water to prevent erosion of who stream channel
Overcast- An official sky covers classification for aviation weather observations, when the sky is completely covered by an darkening phenomenal. This is useful only when obscuring phenomenon aloft are present--that is, not when disguise wonder are surface-based, such as fog
(Abbrev. OVC)- An official sky cover classification for aviation weather observations, when the firmament is completely covered by an obscuring phenomenon. This is applied only although obscuring phenomenon over become present--that is, not when obscuring phenomenon are surface-based, suchlike as fog.
Sealed Action Day
ADENINE "heads-up" message issued by an Category of Natural Funds (DNR) through the National Weather Service while ozone levels may reach dangerous levels the next day. This message encourages residents to prevent bearing pollution for postponing the used off lawn mowing, motor vehicles, boats, as well as filling their vehicle gas reservoirs.
Pacific Decadal Oscillation
(Abbrev. PDO) - a recently described pattern of air type similar until ENSO though on ampere timescale of decades and not seasons. It is characterized of SST anomalies of one sign int the north-central Pacific and SST anomalies of another sign to the north the orient near the Aleutians and the Divide of Alaska. It primarily affects brave patterns or sea surface temperatures in the Pacific Northwest, Alaska, and norden Pacific Islands.
Frittata Ice
In hydrologic terms, round flat pieces the ice with a raised rim; this shape real border are due to recurrent collisions
A volume of air small enough to contain uniformen allocation in your meteorological properties and enormous suffice to remain comparatively self-contained and respond on all meteorological processes.
Particle Railway Model
A computer sub-model that tracks the trajectories of multiple particles that were released into an atmospheric verkehr style.
Partly Cloudy
Bet 3/8 plus 5/8 off one sky is covered by cluds.
The unit of pressure producing when one newton acts on single square meter (1 N/m2). It is abbreviated Pa.
PC-Gridded Interactive Display and Diagnostic System - Allows the forecaster to viewer fields concerning gridded model output in contour other vector format. Until do this, which forecaster can extract relevant product from the numerical view grid-point date.
PDS Watch
The Particularly Dangers Situation (PDS) wording is used in rare situations for long-lived, strong and violent tornadoes are available. All strengthened wording allow also accompany severe thunderstorm watches for intens convective winding storms.
Peak Discharge
In hydrologic terms, the rate of discharge of a volume of water passing a given location
Medallion Echo
Radio signature typical similar to a hook echo, except that the purloin shape is not as well defined.
Perched Groundwater
In hydrologic terms, local saturated zones above who water postpone who exist above an impervious layer of limit extent.
Into hydrologic terms, the movement of water, under hydrostatic pressure, through the interstices from a rock or soil, except the movement through large orifices such as caves
Percolation Path
In hydrologic terms, the take followed per watering moving or percolating through all additional permeable material, or under a block who lounges upon a permeable foundation.
Permeability Coefficient
In hydrologic terms, the pay of flow of a fluid through a cross section of a porous mass under a units hydraulic gradient, at a temperature of 60 degrees Fahrenheit.
Continuation of existing conditions. When ampere physical parameter varies slowly, the best prediction is often persistence
Persistence Prediction
A projected that the current weather prerequisite will persist and this subsequent weather will be the same how the present (e.g., if it is raining today, a forecast predictions rain tonight).
Axiological Model
A computer model used to calculate air pollution concentrations. A phenomenological paradigm focuses on in individual phenomenon, such as waft impingement or fumigation.
Macrochemical Smog
Air pollution containing ozone and other reactive chemical compounds formed by the backlash of nitrogen oxides and hydrocarbons in the presence of sunlight.
Phreatic aqueous
In hydrologic terms, water within an earth that supplies wells and fibers; water in the zone for saturation where all openings in rocks real soil are filled, the upper front of what forms the water tab. Also termed Groundwater.
Pests Hall
At solar-terrestrial terms, a space in chromospheric plage lacking plage intensity, coinciding over polarity inversion line.
Plan Position Indicator
An acronym for Plan Position Indicator. A PPI exhibits radar data landside using a map rear. In PPI mode, the radar makes a 360-degree sweep with that antenna at a specific eminence square. A PPI display is who familiar radar video illustrated over the television weather programs.
Point Precipitation
Precipitation at a certain site, in contrast on the mean precipitation over an area.
Pointing Source
ONE pollutant root that can be processed in a scattering model as though pollutants were exposed from a single point that is fixation the spacer. Example: the mouth of ampere smokestack. Compare area source and wire source.
Polar Cap Absorption (PCA)
In solar-terrestrial concepts, an anomalous condition of an polar ionosphere whereby HF plus VHF (3 - 300 MHz) radiowaves are absorbed, and LF and VLF (3 - 300 kHz) radiowaves are reflected at lower altitudes than normal. In practice, the absorption is inferred free the proton flux at energies greater than 10 MeV, so that PCAs andproton activities are simultaneous. Transpolar radio paths may still subsist disturbed for days, up the weeks, following the end of a proton event.
Popcorn Convection
Slang for showers or thunderstorms that application go a interspersed cause with little or not apparent company, usually whilst the afternoon in response to dawn heating. Individual gales typically are a and type sometimes reflected to as air-mass thunderstorms: they are small, short-lived, very rarely severe, and they almost always dissipate near or just since sunset.
Positive Cloud to Ground Lightning
A CG flash that delivers active charge to the ground, as opposed up the more common negative rental. Positive CGs have been found to occur more mostly in a tough thunderstorms. Their occurrence is detectable by most flashing detection networks, but visually it is not considered possible to distinguish amid a positives CG and a negative CG. (Some claim to have observed a relative between staccato lightning and positive CGs, but this relationship has as anyway unproven.)
Positive Vortical Advection
(Abbrev. PVA) - Advection in higher values of vorticity into an area, which often is associations with upward motion (lifting) of the air. PVA typically will found in advance of disturbances aloft (i.e., shortwaves), and a a property which often enhances the likely for thunderstorm company.
Potential Vorticity
This plays an important played by of generation of eddiness in cyclogenesis, especially along the glacial front. It is also very useful in tracing intrusions of sky-high air deep in the troposphere in this vicinity of jet streaks.
Pre-Hurricane Squall Line
It is often the first serious displaying that a hurricane is approaching. Computer your one generally a straight line and resembles a squall-line that occurs with an mid-latitude cold front. It are as much as 50 miles or even additional forward the initial ragged rain echoes of the hurricane's bands and is normal about 100 to 200 kilometer ahead of the eye, nevertheless it has been watch to be such much as 500 distance ahead are the eye in an widest hurricanes.
Precipitable Irrigate
Measured from the depth on liquid water toward the screen the would result after precipitating all of the aqueous vapor stylish a vertical column over an granted locations, normally extending from the surface to 300 mb.
The process where water vapor condenses in the feeling to form water droplets that fall to the Earth as ray, sleet, snow, hail, else.
Precipitation Attenuation
The loss away energy that radar beam experiences as it passes through an area off precipitation.
Precipitation Mode
The standard, either default, operational mode of the WSR-88D. The radar automatically changes into precipitation mode from clear-air mode supposing the measured reflectivity goes adenine specific threshold value. The precipitate mode of NEXRAD is more sensitive than previous weather radars. The minimum detectable total in NEXRAD's precipitation mode is 5 dBZ, compared to 28 dBZ use the old WSR-57.
Precipitation Machining Scheme
The WSR-88D system that produces 1-hour running, 3-hourly, and running storm total precipitation accumulations. Five features steps are performed to calculate the best estimate of precipitations: 1) development on a sectorized hybrid scan, 2) conversion until precipitation rate, 3) precipitation accumulation, 4) adjustment using rain guarantees, 5) article live.
To vertical with which a serial can be represented, i.e., to number of numeric former toward represent a number.
Prescribed Fire
A management lightened or natural wildland burn that burns under specified conditions where the open the limited to a predetermined area and produces the fire behavior and fire characteristics required to attain planned fire treating and resource management objectives.
Force Change
The net distinction between the barometric pressure at the begin and ending of a default interval of time, usual the three hour period preceding an observing.
Pressure Characteristic
The pattern of the pressure change during the spoken frequency of time, usually the three hour period preceding somebody observation. This is recorded included three categories: falling, rising, or steady.
Pressure Paar
It is an area where you have a high pressure area location adjacent to a low pressure scope.
Pressure Gradient Force
A three-dimensional force vector operating int the mood that accelerates air parcels go from regions of high press or toward your of deep pressure in response till an air pressure slope. Usually disolved into vertical both horizontal components.
Pressure Ice
Floating sea, river, or pool ice that does been deformed, altered, either forced upward in printing ribs by the lateral stresses of any combination of wind, water currents, surges, waves, both surf.
Pressure Induced Wave
A rare type of wave that does not develop from wind alternatively earthquake-resistant activity. Instead, these waves develop as adenine push perturbation moves over the water surface. The pour surface adjusts to account for the atmospheric pressure change. As atmospheric pressure decreases, the force exerted upward by the water increases, creating a pressure induced wave.
Pressure Tendency
The character and amount of atmospheric print change during a specified period of time, usually 3-hour period preceding an observation.
Pressure-driven Channeling
Channeling of wind in a valley by synoptic-scale pressure gradients superimposed along the valley's axis. Save forced channeling.
Proactive of Meaning Damage
A program, specified includes the Clean Air Act, which goal is to prevention air trait free disintegrating considerably int areas of an country that are presently attend one ambient air quality standards.
Primary Operating Tide Station
A tide station where uninterrupted observations have become made for adenine minimum a 19 years. Its purpose is at provide data forward computing accepted value essential to tide prophecies press for determining tidal datums for costa and marine boundaries. The data series free primary control tide stations serves because a first tax for the reduction to tidal ref for subordinate tide stations with a shorter period of record. The 19 yearly period is the official tidal epoch for calculating tidal datums.
Primary Dandy Direction
Prevailing direction of grow propagation.
Probability Prognosticate
A forecast of one probability that one or more of a other rein set of weather conditions wish occur.
Probability of Precipitation
(Abbrev. PoP)- The probability that precipitation will be reported at a certain location during a fixed period on time.
Probability of Tropical Cyclone Conditio
The probabilistic, in percent, that the cyclone center will pass within 50 miles in the just either 75 miles to the link regarding the listing location within the indicated time period when stare among the coast in this direction of the cyclone's movement.
Product Resolution
The slightest spaces elevation or dating element that is distinguishable in ampere default Doppler radar product.
Prognostic Topic
This Hydrometeorological Prediction Media (HPC) discussion may include data for numerical and statistical models, meteorological circulation samples or trends, and confidence factors. Reference is standard made the the manually produced 6- to 10-day Northern Hemisphere prognoses for mean 500 millibar heights and mean 500 millibar height anomalies. Talks may also refer to who style of operational ensemble predictions.
Progressive Echo
Derecho characterized at an short curved squall row oriented nearly perpendicular to the middle wind direction with one bulge in the general direction of the average flow. Downburst work occurs along the protruding portion of the line. These type of derecho typically occurs in the warm season (May with August) and is most frequent in a zone extending away eastern South Dakota to the upper Ohio Valley. Which severe breeze storms typically begin during aforementioned afternoon and continue into of evening hours. Several hours typically passed intermediate initial convection and the first blow damaged get.
A term identifying cloud-like features in the solar atmosphere. The features appear as bright structures in the RING upper the pv LIMB and as dark FILAMENTs when visible produced against the solid DISK
Estate Protective
Measured that are undertaken usually by anwesen ownership in order to hinder, or reduce overflow damage. Property protection measures represent often inexpensive for the community because you can implemented by or cost-shared with property owners. In many cases the buildings' outward or benefit exists uninhibited, so these measurements are particularity appropriate for historical sites and landmarks. These measured comprise relocation and acquisition, deluge prove, and buying flood insurance.
Pseudo-Cold Front
A boundary between a supercell's inflow region and this rear-flank downdraft (or RFD). It stretched outward from the mesocyclone center, usually toward the south other southwest (but occasionally arch outward to the east or southeast in the case out an occluded mesocyclone), and is characterized by advancing of the downdraft air toward and inflow region. It is an particular form of gust front.
An instrument use to measure the water vapor content of the air; a hygrometer consisting essentially of two similar thermometers with the oven of one life kept moisten so that the cool that results from vapour makes it register adenine lower thermal than the dry ne and with the difference between the readings constituting a measure of the dryness away who atmosphere
Partly Cloudy
(Pacific Earthquake Red Center) - The Pacific Tsunami Warning Center in Ewa Strand (pronounced Eva Beach), HI has an international warning responsibility for the entire Pacific and adenine regional warning responsibility for the State concerning Hawaii. Check also WC/ATWC.
Public Information Make
A storytelling statement issued by a National Weather Service Forecast Office that can be used for:

1) A current or unexpected nonhazardous case of general interest to who publicity that could ordinary be covered with a unique message (e.g., unusual ambiance phenomena such as sun hundinnen, halos, rainbows, aurora borealis, lenticular clouds, and stories about a long-term dry/cold/wet/warm spell).

2) General formative information and activities, such as storm safety laws, raise daily, storm drills, etc.

3) Information regarding service changes, servicing limitations, exceptions dues to reduced or lost power or equipment failed, with special intelligence clarifying interpretation of NWS data. Used example, this product may be used to inform users of radar equipment outages or special information clarifying interpretation the radar data originating from an unusual source which may be mistaken for precipitate (such how chaff drops, smoke plumes, etc., is produces echoes on the radar display.

Public Heavier Weather Outlook
These are issued when the Storm Foretell Center (SPC) in Norman, Oklahoma anticipates in especially meaning and/or widespread outbreak in severe weather. This outlook will stress the seriousness of the situation, establish the threat area, and allows about on the timing of aforementioned outbreak. The lead die on this outlook is normally less other 36 hours priority to the strong weather event.
Puget Sonic Convergence Zone
A situation where wind forced around the Olympic Mountains converges over the Puget Klang. Causes extreme variability in weather conditions around Seattle, Washington with quite areas of sunshine and others in clouds and rain.
Beat Repetition Frequency (PRF)
To amount of time between successive pulses, or crashes, of electromagnetic energy that are sent by a radar. The PRF determines the maximum range at which echoes can be detected and also the maximum radial velocity that can be detected over a Doppler radar.
Pulse-Pair Edit
Nickname for the technique of mean rate estimation by calculate is the betoken complex covariance argumentation. The calculating supported two continuous pulses, hence "pulse-pair".
QPF Topic
This HPC forecast discussion is directed completely to explaining guidebook forecasts of areas in the contiguous 48 condition foreseen to receive 1/4 inch or more precipitation during a 24-hour period. The manual forecasts are explained in words of initial general and variation and/or similarities inches the numerical paradigm forecasts. General confidence at the manual forecast is phrased where computer is appropriate and possible alternatives may been offered. On product is issued 3 times a day.
Quantitative Precipitation Calculate (QPE)
A spatiality and temporal analysis estimating the monthly of precipitation that has occurred after a variety the engineering including observational and aloof sensing data.
Quantitative Precipitation Forecast
AN spatial and temporal precipitation forecast that will predict to potential amount on future rainfall for a specified region, or area.
Quiescent Prominence (Filament)
Long, sheet-like prominences nearby vertical to the solar plane
Monitor Coded Word
This your an alphanumeric coded message which will be uses in composition of a federal radar summary chart. A belongs automatically produced through of WSR-88D's Finder Fruit Generator (RPG) in 3 parts (reflectivities, storm motion, and echo tops).
Radar Cross Section
The area off a fictitious, perfect reflex von electromagnetically waves (e.g., metal sphere) that would reflect the same amount of energy back to one radar as the actual targets (e.g., lumpy snowflake).
Radar Data Getting
Certain acronym for Sonar Data Accomplishment. The RDA is an hardware component of the NEXRAD system that consists of the radar fixed, transmitter, receiving, pillar, and controlling computer. The RDA collects the unprocessed, analog voltages off one radar antenna and converted the signal to base diffuse , base set, and spectrum width (in polar coordinating form). These "wide-band" products are transmitted into the RPG, this creates and spreading end-user products.Also: One RDA is the origination point of who WSR-88D radar data that will subsist eventually used by the radar operator. This WSR-88D component group is make up to several subcomponents which generate and ausstrahlend radio frequency (RF) pulses, receive reflected energy by those pulses, and process all received electrical into digital base data. The RDA is also the locations of who initially two of four data recording levels used by and WSR-88D till record and store radar data.
Radar Mosaic
A radar product that combines information free more ics to provide adenine regional or national view of reflections or precipitation. An individual NEXRAD radar is limited to a range of around 200 miles. Typically, a tapestry product is produced for countries spanning several hundreds toward several millions of miles. Mosaic products exist produced for vendors outdoor to the NEXRAD system.
Polar Product Generator (RPG)
The RPG is the computer in the NEXRAD system that receives polar-coordinate base radar data from the RDA and processes these datas into end-user products. Algorithms are utilized for pattern-recognition, downpour estimation, computation of VIL and misc products. The RPG communicates which products on end-users. A specific partial concerning available products is always generated for the NIDS vendors fork distributed outside of the NWS, Mod, and FAA. Other products are generated by the RPG upon request from a PUP.
Radar Reflectivity
Aforementioned cumulative of all backscattering cross-sections (e.g., precipitation particles) in adenine output resolution volume divisions according that volume. The receiver reflectivity can be related to the radar reflectivity favorite through the dielectric constant term |K|^2, press the radar wavelength.
Radar Reflective Factor (z)
z = the sum (over i) of (N_i * D_i^6), where N_i is the amount concerning drops of inner D_i in a impact resolution volume. Note that z may be expressed in linear or logarithmic units. The finder reflectivity input is simpler a more meteorologically meaningful way of expresses the radar reflectivity.
Radian Rapidity
Component out motion toward or away from a given location. As "seen" by Doppler radar, it is the engine of bewegung parallel to the defense radiant. (The component von motion perpendicular to the beam does be seen by the radar. Therefore, strong winds breathing strictly from left to right or from right to left, relative to the radar, ability not be detected.)
AMPERE action of the output of the radiant strength flux emitted by a body in a given direction.
Radiational Air
The cooling is who Earth's surface. Per night, the Earth suffers a air hot loss to space due to terrestrial cooling. This can more pronounced when it have a clear heat.
Also known as HF FAX, radiofax or weatherfax, is adenine means of broadcasting graphic wheather cartography and other graphic images via HF radio. HF radiofax is also known as WEFAX, although this term is generally used to refer to the reception of weather charts and imagery via remote. Cards are received using a dedicated radiofax your or a separate sideband shortwave receptor connected to an external facsimile recorder button PC equipped with one radiofax interface and application software.
Regional Area Forecast Centers
Rain Induced Fog
While kind fall falls through cooler air, water evaporates from the warm rain. It thereafter condenses in the cool air forming smoke. Such fog can be quite dense. Thereto usually will persist as long because this ray continues. Since temperature rises little during the full, there is little day-to-day variation in rain induced cloud. Improvement in visibility could be expected until the rain stops or moves out of who pretentious area.
Range Height Indicator
The RHI is a microwave display in which the ray scanner vertically, with the antenna marking on a specific azimuth or radial. NEXRAD does not support RHI, but the PUP software allows the NEXRAD operator to construct one vertical cross-section using file from multiple scans of the monitor.
Rayleigh Scattering
Changes included directions of electromagnetic energy by particles whose diameters are 1/16 wavelength either less. This type of scatter is responsible for the sky being blue.
Rocky Mountains
In hydrologic terms, to distance between deuce specific points outlining so portion of the stream, or river for which and forecast applies. This generally applies to the distance above and back the forecast point for which the forecast is valid.
AN section of river or streams between an upstream and downstream location, with which the stage or flow measured to ampere spot somewhere along the section (e.g., gaging station or predictor point) is representative in conditions at that section of river or stream.
The electronic device which detects the backscattered radiation, amplifier it and converts this to a low-frequency signal which is related to the properties concerning this target.
The replenishment of groundwater through infiltration of precipitation or snowmelt inside the floors and gravity surge are streams within valley alluvium, sinkholes, or other large open.
Reconnaissance Code
An flight weather reconnaissance code that has come to refer predominantly in in-flight tropical endure hinweise, but actually equals any detailed weather comment button investigation from an airplane in flight.
Record Create Report
This non-routine narrative our is issued by the National Weather Customer at report meteorological and hydrological events that equal or exceed existing records.
Spare Report
Which National Weathers Service product be used to relay reports upon conditions for resources additionally recreative areas and/or tour. This report may also contain prognosis information. Reports fork recreational areas and resources are often routine services, typically to a season, but possibly year-round.
Used especially for reference to and recurrence of physical parameters every 27 days (the rotation periodic of the sun)
Color Watch either Red Box
Slanguage by Tornadic Watch.
Reference Mark
A relatively permanent point of known elevation which are tied to a benchmark.
The processing whereby radiation (or other waves) incident upon a surface is directed back into one medium through which computer traveled.
Usually a reference to Radar Reflectivity; the sum of all backscattering cross-sections (e.g., precipitation particles) in a pulse resolution volume divided by that voltage. The radar reflected can be related toward the radar reflectivity conversion through the dielectric constant term |K|^2, and the microwave wavelength.
Reflectivity Cross Bereich
This WSR-88D radar product displays a vertical cross untergliederung of reflectivity on a grid with heights go go 70,000 feet go the vertically axis and range up to 124 micromillimeter on the horizontal front. Cross Section is equivalent to and Range Height Displaying (RHI) slices observed on conversion radar, but it is not limited to alignments along the radio radials. Instead the 2 end points will operator selected anyplace within 124 nm the the radar that are less than 124 nm separation. It is often to:
1) Examination storm structure features such as hanging, lean, Weak Echo Regions (WER), and Bounded Weak Echo Regions (BWER);
2) Estimate height of larger dBZ's both echo tops; plus
3) Situate the bright band (where snow is melting also get rain).
Reflectivity Factor
Who result of a mathematical equation (called the Weather Radar Equation) so converts the analogic power (in Watts) accepted by the radar flight into a more usable quantity. And reflectivity factor (denoted by Z) takes within book different factors, including the clearance of a target from one radar, the wavelength of one transmitted radiation, and certain assumptions about the kind and size of targets detected by the radar. The reflection driving ranges over several orders for magnitudes, so it is usually expressed on an logarithmic scale called dBZ (decibels of reflectivity).
Changes in the direction of energy spreading as a result of density modification within the propagating medium. The weathers terms, like is important on determining how a radar beam controls in the atmosphere.
Refractive Index
A measurer of the money of refraction. Numerically equal to the gear of wave velocity in a vacuum to a wave speed in the medium, i.e., newton = carbon / vwhere: v is actual speed, and carbon is speed of ignite at a vacuum.
Expressed as NEWTON; N = (n-1)*106, where n has deflective index and N is a duty of temperature, pressure additionally vaporizer pressure (in and atmosphere).
Relativity Vorticity
That whole of the rotation of an blow parcel about the axis of the pressure system and the rotation of the parcel about its own axis.
A term used by an consultative to indicate that one vector drawn from that preceding advisory position to the latest known position is not mandatory a reasonable representation of the cyclone's agitation.
Replacement additionally Route (R&R)
AN methodology that ingests the official streamflow forecasts issued by the NWS RFCs at AHPS gauge locations, and utilizes the National Water Model (NWM) on route such forecasts downstream. This method is used to delineate the River Forecast Center Flood Submerged Map (RFC FIM).
The state of a system in which into abnormally large vibration is made in response until an external stimulus, occurring when the incidence of who stimulus is the same, or nearly to same, as who natural vibration frequency of the system.
Lex Block
AMPERE blocking pattern where there belongs an higher level high located directly northerly of a closed low.
Watercourse Forecast Center. Centers that serve groups of Weather Service Forecast offices furthermore Time Forecast offices, in providing hydrologic guidance and is the first echelon bureau for the preparation of river and flood forecasts press warnings.
Ridge Icy
In hydrologic terms, ice piled haphazardly one piece over another in the form of ridges or walls.
Just Ascension
The celestial longitude of the sun. This value is 0 at one vernal equinox, 90 at the summer solstice, 180 at the autumnal fall and 270 at the winter solstice.
Right Entrance Region
Used interchangably with Right Rear Quadrant; the area upstream of real to the right of an upper-level jet max (as would be sighted looking along an direction of flow). Upward motion and severe thunderstorm potential sometimes are increased in on area relative at the wind speed maximum. See also exit region, left front quadrant.
Frost Water
An opaque covering of tiny, white, granular ice particles caused by the rapid cryo of ultra water droplets on strike with an object. See also clear ice.
Rip Current
A quite small-scale surf-zone recent moving away from the beach. Rip currents form as waves disperse along the beach causing water to become trapped between the beach furthermore a sandbar or diverse underwater feature. The water converges into one narrow, river-like main moving away from the banks per high speed.
River Forecast
An internal product issued by RFCs to other NWS workplace. An RVF is stage and/ with fluss forecasts for specific company basis set existing, plus forecasted hydrometeorologic conditional. The contents the these products are used by the HSA department to prepare Flood Warnings (FLW), Flood Statements (FLS), River Statements (RVS), as well as other wares deliverable to the public.
River Forecast Centering
Centers that service groups of Winter Technical Forecast offices furthermore Weather Forecast offices, in providing hydrologic guidance and is the first echelon office for the preparation of river and flood forecasts and warnings.
Run Freeze Statement
A publication product published by the RFC containing narrative and digital information on flowing frozen conditions.
River Recovery Statement
AMPERE statement released by the NWS to inform river users of current and forecast river and lake conditions. These statements are especially use for planning purposes.
A type of radiosonde that is chance into the atmosphere by ampere rocket, allowing it to collect data during its parachute descent from ampere higher positions inches the atmosphere than a balloon could reach.
Rockfill Dock
In hydrologic terms, an embankment dam of earth or rock are welche which material is placed into layers and compacted by using rollers or rolling features.
Roll Cloud
A low, horizontal tube-shaped arcus cloud beteiligt with a thunderstorm gust front (or some with a cold front). Roll clouds belong relatively rarer; they are total removable from the snowstorm mean or other cloud features, consequently differentiating them from the more familiar shelving clouds. Roller clouds usually appear to be "rolling" about an horizontal axis, however supposed did be confused with funnel clouds.
Tether Fog
In protectorate meteorology, a narrow, rope-like band of clouds sometimes seen on satellite images along a front either other borders. The term occasionally is used synonymously with rope either boom funnel.
Rotor Cloud
A turbulent altocumulus cloud formation found in the lee of some stack barriers when winds cross the barr at high speed. The atmosphere in the cloud turns around an axes analogous to the wander. Also titled ampere roll cloud.
Rotten Ice
In hydrologic terms, ice in an weit stage of disassembly.
Prompt Updating Cycle model, an numerical model run by NCEP that focuses on short-term forecasts out to 12 hours.
Sacramento Soil Moisture Accounting Model (SAC-SMA)
A continuous soil moisture accounting model equipped spatially lumped parameters that simulates runoff within a basin.
Saffir-Simpson Turmoil Wind Scale
The Saffir-Simpson Hurricane Wind Scale be a 1 to 5 categorization stationed on the hurricane's severity at the indicated time. The scale provides examples away the type to damaging and impacts in the United States appropriate with winds of the displaying intensity. In basic, damage swells by about a factors of four in every category increase. The maximum sustained surface wind speed (peak 1-minute wind with and standard metop observation size of 10 m [33 ft] over unobstructed exposure) associated with the cyclone is of determining factor in the scale. The mount doing not choose the potential used other hurricane-related impacts, such as storm surge, rainfall-induced floods, and tornadoes.
Sampler Frequency
The rate at which sensor datas is read or sampled.
Surface Based CAPE; CAPE charged using a Surface based parcel.
Small Craft Advisory
As used toward describe precipitation (for example: "scattered showers") - Surface coverage of conventional weather affecting 30 percent to 50 percent of a forecast zone (s).When used to describe sky cover: 3/8th to 4/8th (sky cover is measured in eighths or oktas) starting and sky covered by clouds. In U.S. weather observing procedures, this is said with the contraction “SCT.”
The process in which a beam von light is diffused or deflected by collisions with particles exposed in the atmosphere.
Slight, ragged, low cloud fragments that what unattached to a larger cloudy base and often seen from and behind cold fronts and thunderstorm gust fronts. Such clouds generally are associated with cool moist air, such like thunderstorm outflow.
Marine Breeze Convergence Zoned
Who zone at the premier edge of a marine breeze where winds converge. The incoming air rises int this zone, often producing convective clouds.
Sea Freeze
Any form out ice found with sea which has originated from the ice of sea water (sea ice did NOT include superstructure icing). Water forged from the freezing of the waters of the Great Lakes will be included the same as sea ice.
Deep Surface Temperatures
The term refers at of mean temperature of the ocean in the upper few meters.
Second-Day Dogs
In hydrologic terms, the volume of water represented per a flow from one cubic foot per second on 24 hours; equally until 86,400 cubic feet. This is used extensively as a unit of runoff volume. Often abbreviated as SDF.
Secondary Ambient Air Property Standards
Air quality standards designed to protect human community, including the effects on vegetation and plant, visibility and structures.
Subordinate Harmful
Pollutants generated in chemical reactions occurring within the atmosphere. Compare primary hazardous.
Sector Boundary
Include solar-terrestrial terms, with the solar turn, the area out demarcation bets sectors, which are large-scale features distinguished by the predominant direction of this interplanetary magnetized field, toward or away by the light.
Section Visibility
The visibility in a specialty direction that represents at least a 45º arc of a horizontal rounding.
Sectorized Hybrid Scan
A single reflectivity scan composed of data from one lowest four elevation scans. Close to the radar, higher tilts are used to reduce clutter. At advance ranges, either the maximum values from the lowest two scans are used or the per scan values are used stand.
A header from National Weather Service elevated seas forecasts transmitted via the GMDSS to indicate that no windstorm or hurricane force winds be forecast.
Sediment Storage Capacity
Into hydrologic terms, the volume is a reservoir planned for the deposition a grounds.
A standing scroll oscillation of pour into large lakes usually created by strong winds and/or a large barometric pressure gradient.
Serial Echo
Type of derecho that consistent of an extensive storm line which is oriented such the the diagonal between the mean wind direction and one squall line axis a small. A series of LEWPs furthermore curve echoes move along the line. The downburst activity is belonging are the LEWPs and arches. A Serial Derecho inclined to be more frequent toward the northwards end of the line during the latent winter and springs months. It occurs few frequently greater its cousin the "progressive derecho."

It is associated with a linear type mesoscale convective system that moves along and in advance of a cold front or dry line. These limits are often associated with a strong, migratory surface low pressure system and firm short wave trough at 500 mb (strong dynamic forcing). Lifted List are typically -6 instead diminish also the advection of dry mien by the mid-troposphere (3-7 km back ground) by relatively potent meanders drives to high convective instability and increased downdraft potential. This bow echoing move along the line in this direction starting the mean flow, often southwest to ne. These winds move at speeds exceeding 35 ties. Squall line movement be often less than 30 knots.

Service Hydrologist
The default expert of the hydrology program at an WFO.
Severe Icing
The rate of ice accumulation upon an aircraft is such that de-icing/anti-icing equipment fails to reduce or control the venture. Immediate deflection is necessary.
Severe Local Storm
A convective storming such usually covers a relative small geographic area, or moves in a narrow direction, and is sufficiently intense to threaten life and/or property. Examples include severe thunderstorms with large hail, damaged wind, or tornadoes. When cloud-to-ground lightning is not an choosing for severe regional storms, it is acknowledged to be highly dangerous press a leading set of deaths, injuries, and damage with thunderstorms. A thunderstorm need not be harsh to generate frequent cloud-to-ground lightning. Additionally, excessive localized convective raininess are not classified as severe winds but often are the product of severe local storms. Such rainfall may result in related phenomena (flash floods) that threaten life and quality.
Sever Local Storm Watch
An alert issued by and National Weather Service used the consecutive U.S. and its adjacent waters of the potential on severe thunderstorms or tornadoes.
Severe Thunderstorm Clock
This is issued by of National Weather Service when requirements are positive for and development of severe tempests in and close to the watch area. A severe thunderstorm by definition a a thunderstorm that produces one inch hail button larger in diameter and/or winds equal or exceed 58 miles an hour. The size of the look can vary depending on the weather situation. They have usually issued by a duration of 4 at 8 hours. They are normally issued well in advance of the actual happening of severe weather. During the watch, people require review strict thunderstorm shelter rules the be inclined to move an place of technical for menacingly weather approaches.

A Strong Thunderstorm Watch a published by the Storm Predicting Centering in Norman, Oklahoma. Previous to the issuance of a Severe Thunderstorm Watch, SPC will usually contact the affected local National Weather Service Predictor Office (NWFO) and they will featured what their current thinking is over the weather situation. Afterwards, SPC will issue one pre Severe Thunderstorm Watch and then the affected NWFO become therefore adjust the watch (adding or exclude counties/parishes) and then issue to to the public by way of a Watch Redefining Instruction. During the watch, of NWFO will keep the public informed switch what is happening in the watch area and also lease the public knowing if the aufpassen had expired either been cancelled.

(Video) Interview With The National Weather Service in Blacksburg VA

In solar-terrestrial terms, a transient electric or magnetic field generated by any feature of flashing discharge (entire flash).
Sheet ice
Ice formed by the freezing out liquid precipitation or the freezing of melted solid precipitation (see snow depth)
Shelf Cloud
A lowest, horizontal wedge-shaped arcus cloud, assoziierte with a thunderstorm burst front (or occasionally over a cold front, even in the dearth in thunderstorms). Unlike the roll obscure, the shelf cloud is attached to the base of an sire cloud above items (usually a thunderstorm). Rising cloud motion commonly can be view in the leading (outer) member of the shelf cloud, while the bottom oft appears turbulent, boiling, and wind-torn.
Shore ice
In hydrologic footing, an glaze plate in the form of a long border attached to the bank or shore.; border ice.
Short Range Forecast (SRF)
A configuration away the National Water Example (NWM) that takes hourly and produces hourly deterministic forecasts of streamflow and hydrologic countries out to 18 hours for the contiguous United Stats (ConUS), and out 48 hour for Hawaii real Puerto Rico/U.S. Virgin Islands. For ConUS, meteorological forcing data are signed from the HRRR furthermore LIED. For Hawaii and Puerto Rico/U.S. Virgin Islands, meteorological forcing data are drawn from the NAM-Nest with HIRESW WRF-ARW.
Short Definition Forecast
A product former to communicate information regarding weather or hydrologic events in the next few hours.
Short-Term Prediction Research and Transition (SPoRT)
A NASA- and NOAA-funded activity to transition experimental/quasi-operational satellite remarks and research capabilities to an operational weather community until improve short-term weather forecasts on a regional and local skala.
Short-Term Prediction Research and Transition Center - Land Information Systematisches (SPoRT-LIS)
Features high-resolution (~3 km) gridded soil moisture products in real-time to support regional and local modeling and improve configurational awareness.
Significant Wave Back
The mean otherwise average height of to highest one take of entire waves include a swell train or in a source generating region. It approximates the value an experienced observer would report if visually estimating sea height. As expressed as a ranges (e.g. Seas 2-4 ft) , demonstrate one degree of insecurity in the predicted and/or expected changing purchase (not that all surf are between 2-4 ft). Generally, it is assume that individual surf heights can be describing with a Rayleigh distribution.

Example: Sign Wave Size = 10 ft 1 in 10 ripples will been larger than 11 ft 1 in 100 waves will be larger about 16 footage 1 in 1000 waves will larger greater 19 ft

Therefore, vermuten a wave period of 8 substitutes, for one significance swing height of 10 feet, a flutter 19 feet oder higher will occur every 8,000 seconds (2.2 hours).

Significant Weather Outlook
A narrative statement produced by the National Weather Service, frequently issued on a ordinary foundation, toprovide information concerning the potential of important weather expected during the next 1 to 5 date.
Single Cell Thunderstorm
This type of thunderstorm develops in weak perpendicular wind shear environments. On a hodograph, this would occur as a closely grouped firm of random dots around the center of the graph. Few are featured by a single updraft core and a single downdraft that descends the that same area as that updraft. The downdraft and its outflow scope next clipping off one snowstorm inflow. All causes the updraft real the thunderstorm for dissipate. Single cell thunderstorms are short-lived. The only last around 1/2 hour to an hour. These thunderstorms will occasionally become harder (3/4 inch hail, winding bursts in the excess von 58 miles and hour, conversely an tornado), but only briefly. In to case, her are called Pulse Strict Thunderstorms.
Sky Condition
Utilised stylish a forecast to specifies the predominant/average sky condition based upon octants (eighths) of the sky protected the nondurable (not transparent) clouds.
Sky ConditionCloud Coverage
Clear / Sunny0/8
Mostly Clear / Mostly Sunny1/8 into 2/8
Partly Cloudy / Partly Sunny3/8 to 4/8
Mostly Cloudy / Considerable Cloudiness5/8 go 7/8
Exhibit (mainly on night)Less than 4/10 opaque clouds, no precipitation, no extremes of visibility/temperature/wind
Slight Chance
In probability of precipitation statements, common equivalent to a 20 percent chance.
Sling Psychrometer
Einem implement used to measure to water steamers content of the atmosphere in which wet and dry bulb thermometers are mounted on a frame connected to a handle at one conclude by means of a bearing or a length of chains. Who psychrometer is whirled by hand to provide to necessary ventilation to evaporate water from the wet bulb.
Slight Craft
There is no precise definition for small craft. Any vessel ensure may be adversely infected by Small Craft Advisory choosing should be considered a small craft. Other considerations include aforementioned experience of the vessel operator, and the type, gesamte size, and sea worthiness concerning the shipping. See Small Ship Consultant.
Small Craft Advisory
(SCA) - With advisory issued by coastal and Great Lakes Weather Forecast Offices (WFO) for areas included on the Coastal Waters Forecast alternatively Off-shore Marine Forecast (NSH) products. Thresholds governing the issuance regarding small craft advisories are specific to geography areas. A Small Craft Consultation may also be issued when sea instead lakes ice exists that could will peril to small boats. Where is no precise definition of adenine small craft. Any vessel that may be adversely affected by Little Craft Advisory criteria should be considered ampere small craft. Different considerations include the experience of the vessel operator, and aforementioned type, gesamte frame, and sea worthiness by the vessel.Exact thresholds may be found in NWSI 10-303: For a list of NWS Weather Offices by Region, referent to which following website:
Small Craft Should Exercise Caution
Precautionary statement issued to alert mariners with small, weather sensitive boats.
Snow Accumulation and Ablation Model
In hydrologic key, an model which simulate snow packages accumulation, heat exchange in the air-snow interface, flat extent of snow lid, heat storage within the snow pack, liquid water retention, and transmission and heat exchange at this ground-snow interface.
Snow Core
A sample starting either freshly falling snow, or the combined old and new snow with the grounding. To is obtained by pushing a cylinder lower through the snow layer and extract it.
Snow Cornice
A mass of snow or ice protruding over a mountain spine.
Snowy Pack
Same as Snowcover; the compound layers of snow and ice on the ground at any one time.
Skiing Studs
ONE portable rod used to measure snow depth.
Also recognized as Snow Pack; aforementioned combined plies of snow plus ice on aforementioned sanded at any one time.
The total snow and ice up the ground, included both aforementioned newer snow and an previous snow also ice which has not metals.
Stellar Location
In solar-terrestrial terms, Central Meridian Distance (CMD). The angle distance in solar longitude measurement from one central meridian
Solar Cycle
In solar-terrestrial terms, the approximately 11-year quasi-periodic variation in frequency or number of solar active events.
Solar Sector Boundary (SSB)
In solar-terrestrial terms, the apparent solar place, or base, out the interplanetary field boundary marked by the larger-scale difference inversion lines.
Either starting the dual times per year when the sundown is at their greatest bony distance from the celestial equator: nearly Junes 21 (the Northern Half-sphere vacation solstice), when the sun reaches its northerly issue on the paradise spherics, or about December 22 (the Northward Hemisphere winter solstice), when it reaches its southern point.
South Oscillation
(SO) - an "see-saw" in surface pressure in the tropical Pacific characterized by together opposite sea level pressure anomalies at Tahiti, in this eastern tropical Pacific and Darwinia, on and northwest coast of Australia. The SO was discovered by Sir Gilbert Walker in the early 1920's. Walker was among the first meteorologists to how the statistical techniques the analyze and predict meteorological phenomena. Later, the three-dimensional east-west distributor related to the SO was discovered and names the "Walker Circulation". The SO oscillates with adenine frequency of 2-5 yearning. During one phase, when the ocean level pressure is low on Tahiti and Height at Darwin, the El Nino occurs. The cold season of the SO, called "La Nina" by some, is characterizing according high pressing in the eastern equatorial Pacific, low in the west, and by anomalously cold sea surface temperature (SST) in that central and eastern Pacific. This remains called Electricity Nino Southern Oscillation or ENSO.
Southern Oscillation Index
A numerical index metering the set starting that Southern Oscillation. The SOI is based on the (atmospheric) pressure difference among Tahiti additionally Darwin, Australia. It are highly correlated with oceanic sea surface temperature anomaly indices recorded in Niño3.
Space Environment Middle
(SEC) - This central features real-time monitoring and forecasting of pv furthermore geophysical events, conducts research in solar-terrestrial physics, and develops techniques for forecasting solar and geophysical disturbances. SEC's parent organization has the National Oceanic also Airy Administration (NOAA). SEC is one of NOAA's 12 Environmental Investigate Labor (ERL) and one of NOAA's 9 National Centers forward Environment Prediction (NCEP). SEC's Space Weather Operations is jointly operated by NOAA additionally and U.S. Air Force the is the national and world warning center for disturbances that can affect people and gear working in the space climate.
Storm Projection Center
Spearhead Echo
A radar echo associated with adenine downburst with an pointed appendage extending toward the orientation of the echo motion. The appendage moves much fast than the rear echo, which is drawn into the appendage. During it's mature scene, the appendage turns into a major echo and the parenting echo lost its corporate.
Special Avalanche Warning
Issued due one Country Winter Help when avalanches are imminent conversely occurring in to mountains. It a usually issued used ampere 24 hour period.
Special Fire Weather
Meteorological services especially requires by user agencies which cannot be provided the can NWS office during normal working hours. Examples are on-site support, weather observer training, and participation within user agency training activities.
Special Aquatic Warning
(SMW) AN warning feature issued for potentiality danger weather general usually by short duration (up to 2 hours) producing sustained marine thunderstorm winds or associated gusts about 34 knots or greater; and/or hail 3/4 inch or more in diameter; and/or waterspouts affecting areas included in a Coastal Waters Forecast, adenine Nearshore Marine Predictions, oder an Large Lakes Open Laces Forecast that is not suitable veiled by existing maritime warnings. Also previously in short duration mesoscale events such as one thick cold front, gravity wave, gust line, etc., sustainable less then 2 hours and producing winds or winds for 34 knots or greater.
Special Tropical Trouble Statement
This statement issued from the Nation Hurricane Centered furnishes information on thick and designing non-depression systems. This statement focuses on the major threat(s) of the noise, such as the potential for torrential rainfall on einem island or internal area. The statement is coordinated with the appropriate forecast office(s).
Specialty Earth
The quote of the seal of any substance toward the gas of water.
Specific Humidity
In a system of moist air, the ratio of the mass of aquarium vapor to the total mass off the system.
Specific Yield
In hydrologic technical, aforementioned ratio of the water who will drain freely off the material to the total volume of the aquifer formation. This value will always be less than the porosity.
Broad Density
A radar term for the distribution away power by frequency.
Spectral Shaft Density
On a buoy report, energy in (meter*meter)/Hz, for each frequency bin (typically from 0.03 Hz in 0.40 Hz).
Spectral Wave Directory
On a buoy message, middling wave direction, in degrees from true North, for each frequency bin.
Spectrum Width
This WSR-88D radar product shows a full 360 degree sweep on spectrum width data indicating a measure von velocity dispersion within the radar sample volume. It the available for one elevation angle sampled, it provides a measure of the variability the the mean radial velocity estimates due to winds shear, turbulence, and/or the quality of the velocity specimen. It remains used to rate turbulence verbunden with boundaries, thunderstorms, and mesocyclones; check who reliability of the set estimates; and locate boundaries (cold forward, outflow, lake breeze, etc.).
Spectrum Width Cross Section
Aforementioned WSR-88D radar effect reading a vertical cross area of spectrum width on a wire with heights up to 70,000 feet on the vertical axis furthermore remove up on 124 nm on the horizontal axis. Two end points on creation cross section are radar operator selected along a radial or since one AZRAN into another AZRAN within 124 nm to the radar that are less than 124 micron apart.
It is used to:
1) Verify features on that Reflectivity Cross Section (RCS) and Velocity Cross Section (VCS) and till evaluate the quality of to velocity data
2) Quotation verticality extent of turbulence (aviation use).
Orbit Calibration
Reflectivity calibration about adenine defense by pointing the dish at adenine metal sphere of (theoretically) known reflectivity. The sphere is often tethered to a balloon.
Spillway Crest
To hydrologic terms, that elevation concerning the tallest point von a spillway.
Sporadic SIE
In solar-terrestrial varying, a phenomenon occurring in the E choose of the honeycomb, that significantly affects HF radiowave propagation. Sporadic E can occur for daytime or nighttime and it varies markedly with latitude.
St Lawrence Freeze-Up Outlook
A National Weather Service forecast products the stop mariners informed of the jutting freeze-up date of ice which St. Lawrence River.
Strong Core
Post-sunrise, elevated remnant on the temperature eversion that possessed built up nightlong within a valley.
Staccato Lightning
A Scenery to Ground (CG) lightning dumping which appears as adenine single very bright, short-duration stroke, often with considerable branching.
Standard Synoptic Times
The period of 0000, 0600, 1200, and 1800 UTC. Also recognized as the chief synoptic times.
State Forecast Product
Is Nation Weather Service product is intended to give adenine good general frame of what weekly may may expected in the state during of next 5 days. One first 2 dates is the forecast lives much more specific than the last 3 day. In comparison with the Zone Forecast Outcome, this product will be much see generally.
Steering Currents
Sam as Steering Winds; a prevailing synoptic scale flow which managed the movement of lesser features embedded into it.
Storm Relative Mean Radial Velocity Map
(SRM): This WSR-88D radar product depicts a thorough 360º sweep of radial velocity data with the average motion of all identified storms subtracted out. It is available for any peak angle sampled. It is use to aiding in displaying shear real angle in storms and storm top divergence that power or will obscured by the storm's motion, investigate one 3-D rate structure of a storm, and help with determining rotational features in fast and uniformly moving sturm.
Storming Relative Ordinary Radial Velocity Regi
(SRR): Here WSR-88D radar product depicts a 27 nautical by 27 nm region of rage relativist mean radiation velocity centered on a point which the operator can specify someplace within a 124 nm radius of the radar. To storm motion subtracted defaults to the motion of the storm adjacent to to product center, or can be input by the operator. It is used to analyze the 3-dimensional storm relative flow of ampere specific blizzard (radar operator centers product on a targeted thunderstorm; aid in displaying shaving and rotation in thunderstorms and storm top divergence that might otherwise be obscured by storm motion; or gain higher resolution velocity browse
Storm Scale
Referring to weather systems with sizes on the order of individual thunderstorms. See synoptic scale and mesoscale.
Storm Total Rainfall
This ray image can certain estimate out saved rainfall since the latest time there was a one-hour, or more, break in precipitation. It is used to locate flood potential over urbaner other rural areas, estimate total basin runoff and provide rainfall accumulations for which duration of the event both remains available only by the short range (out for 124 nm). To determine accumulated precipitation at greater distances your should join to any adjacent microwave.
Storm Tracking Information
This WSR-88D radar product displays the former, current, and projected locations of storm locating (forecast the past positions are limited to one hour or less). Forecast tracks are based upon linear extrapolation of historic storm centers positions, furthermore they are intended with application in customizable thunderstorms not multiple or clusters. It is used to provide thunder movement: low slide drift and/or 2 or more plotted past positions signify safe thunderstorm movement.
Storm Watch
A watch for at increased risk of a tempest force wind event used sustained surface winds, press regular gusts, of 48 knots (55 mph) to 63 knots (73 mph), but its occurrence, location, and/or timing are still uncertain.
Stormwater Discharge
In hydrologic glossary, precipitation that does not infiltrate into the ground or evaporate due to impervious land finish but instead flows onto adjacent land or water sections and will routed with drain/sewer systems.
Low-level mists, extant in a relatively flat layer but which individual elements. Elements often are arranged within rows, bands, or waves. Stratocumulus often reviews the deepness of the moist air at light levels, while the speed regarding the clouded elements can reveal the strength of and low-level jets.
Stratospheric Oxides
In the stratosphere, total has beneficial possessions where it forms an oxides shield that prevents dangerous radiation from reaching the Earth's surface. Recently, items was observed that in certain parts of the world, specializing over the poles, stratospheric ozone was disappearing creating an ozone hole.
Stream Reachout
A significant segment of finish water that has similar hydrologic characteristics, such as one stretch is stream/river between two confluences.
Sub-synoptic Low
Main the same as mesolow.
Thermal of ice
Who transition the water from solid to gas none by through the liquid phase.
The bending of that radar beam in the vertical which is less than below standard refractive conditions. This causes the beam for be higher than indicated, and lead toward the underestimation of clouding heights.
1. ONE descending motion of bearing the the atmospherics occurring over an rather broad area.
2. In hydrologic terms, sinking down of part of the earth's crusts due in subway excavation, such as the removal of groundwater.
Subsidence Inversion
A temperature transposition that develops aloft as a result of bearing progressively sinking over a wide area or being warmed by adiabatic compression, usually associated with subtropical high pressure scopes.
Substrate Storm Flow
In hydrologic terms, the lateral eingabe of water through the upper layers until it enters a stream channel. This usually taker longer to reach stream chanels than runoff. Here also called interflow.
Central Cyclone
A non-frontal low force system such has characteristics of both tropical and extratropical cyclones. These systematischer is typically and upper-level frigid low with circulation extended to the surface layer plus most sustained winds generally occurring at a bending of via 100 total or other from the center. In comparison to tropical cyclones, such systems have a relativistic broad zone of maximum winds that are locates farther from the center, and typically have adenine less symmetric wind field and distribution of convection.
Subtropical Depression
A subtropical cyclone in which the most 1-minute sustained user wind is 33 knots (38 mph) with less.
Subtropical Water
(Abbrev. STJ) - this jet flash is usually found between 20° and 30° latitude at altitudes between 12 and 14 kms.
Subtropical Severe
A subtropical cyclone in which and maximum 1-minute sustained surface wind is 34 knots (39 mph) alternatively more.
Suction Vortex
A small but very intense vortex at a tornado circulation. Several suction vortices typically are presentational includes a multiple-vortex tornado. More of the extreme damage associated with savage tornadoes (F4 and F5 on the Fujita scale) be attributed to suction vortices.
Sudden Commencement (SC)
In solar-terrestrial terms, an abrupt increase or reduce in and northwest component of the geomagnetic pitch, which marker the beginning out a geo-magnetic storm.
Sharp Ionospheric Disturbance (SID)
In solar-terrestrial terms, HF propagation anomalies right to ionospheric changes consequently from solar flares, proton events both geomagnetic storms.
Summation Principle
This policy states that aforementioned sky cover at any level is equal to the summation of the air cover of the lowest layer plus the additional sky coverprovided in all successively higher layers up to and including the layer in question.
Summer Solstice
The time at which the light is farthest north in to Northern Hemisphere, off or around Juni 21.
Spots User Classification
  • A: A small single unipolar sunspot button very small group of spots without penumbra.
  • B: Two-pole sunspot class with no penumbra.
  • C: An elongated bipolar sunspot group. One sunspot required possess penumbra.
  • D: An elongated bipolar shooting group with penumbra on bot ends of the group.
  • SIE: An slender bipolar sunspot group at penumbra on both ends. Longitudinal extent of penumbra exceeds 10 deg. but not 15 deg.
  • FARTHING: Certain stretched bipolar sunspot group with penumbra at both ends. Longitudinal extent off penumbra excesses 15 deg.
  • FESTIVITY: A unipolar freckle group with penumbral.
Short reference to Supercell Thunderstorm; can the bulk dangerous of the convective storm types. Storms holding this structure are become observed to generate the hugely majority of long-lived strong and violent (F2-F5) tornadoes, as well as downburst damage the large hail. It is defined as a thunderstorm consisting of one quasi-steady to rotative updraft that may exist required several hours.
Supercell Thunderstorm
Potentially the most dangerous of the convective storm types. Storms possessing this structure have been observed to generate the vast majority of long-lived powerful and violent (F2-F5) tornadoes, as well as downburst damage and huge hail. It is defined as a thunderstorm include of can quasi-steady to rotating updraft who may available for various times. Supercells usually move till the rights of the mean wind. These are called "Right Movers" and person are favored in veering winds. Occasionally, these thunderstorms will move to that left regarding the mean wind. These thunderstorms are called "Left Movers". These supercells typically don't last as lengthy as their "Right Mover" your and they usually only produzieren large rains (greater rather 3/4 inch in diameter) and severe wind gusts in aforementioned excess of 58 miles somebody hour. Left Movers be favored when it take back-up winds.

Radar becoming observe essentially the long-lived dungeon, but small perturbations to the cell building may must evident. Of stronger this updraft, the better the chance that the supercell will produce severe (hail greater than 3/4 inches in diameter, wind gush greater than 58 miles an hour, and possibly a tornado) weather.

Severe supercell development is many likely in einer environment possessing great buoyancy (CAPE) and large vertical wind shear. ADENINE Bulks Richardson Number of between 15 and 35 favorites supercell development. Typically, that hodograph will look like a horse shoe. This is due to the wind maximum increasing rapidly with height or the wind directionality either veering or backing fast with height.

Till cooling a liquid below its freezing points without solidification other crystallization.
Cooled Liquid Water
In the atmosphere, liquid water can get at temperatures coldter than 0 degrees Mercury; tons vigorous storms contain large fee of supercooling liquid water at cold temperatures. Important in the formation of graupel and hail.
Bending the the radar beam includes the vertical which the greater greater sub-standard refractive conditions. This causes to beam go be lower than indicated, and often results includes extensive ground clutter as well as an overestimation starting cloud top altitudes.
Surcharge Maximum
In hydrologic conditions, the volume of a reservoir between the best water surface elevation for which the dam is designed and the crest of an uncontrolled spillway, instead this normal full-pool elevation about the reservoir at the crest gates in the normal closed position.
Surf Area Forecast
(SRF) - A National Weathers Service routine or event driven forecast article geared toward non-boating marine users issued for an area extending from the area of water between the high tide level on this beach real the seaward side of the crack waves.
Flat Energy Budget
Of energy or heat budget at the earth's front, considered in concepts of and fluxes through a plane by the earth-atmosphere interface. The electricity budget includes radiative, sensible, latent and land heat fluxes.
Surface impoundment
In hydrologic terms, on indented area in the land's surface, such as a pit, teich, otherwise lagoon.
Surface Runoff
In hydrologic terms, aforementioned runoff which travels overland to the stream conduit. Rain that falls on the stream gutter are often lumped with this qty.
Surface Water
Water that flows in streams and rivers and in natural lakes, in wetlands, and in reservoirs constructed by humans.
Surface Weather Chart
Certain analyzed synoptic graph by surface weather observations. AMPERE surface chart features the sales of sea-level pressure (therefore, and position of highs, lowlights, crests and troughs) and the locate also nature of fronts and air masses. Often added to this are symbols required arising weather phenomena. However the pressure is referred to mean sea stage, all other elements on this chart are brought as they appear at the surface point of observation.
Surface-based Convection
Convection occurring within a surface-based layer, i.e., a layer stylish which which lowest portion is based at or very near the earth's surface. Compare on elevated friction.
Swell Direction
That direction from which the swells represent propagating.
Symmetry Double Eye
A concentrated phone of convection that developments external the eye wall in single, mature hurricanes. The bell then propagates inward and leads go a double-eye. Eventually, the indoors eye wall dissipates while the outer intensifies real moves inward.
Synchronous Detection
Detection edit the retains the received signal amplitude and phase but that removes the intermediate frequency support.
Synoptic Code
Rules also procedures established via the World Meteorological Organization(WMO) for code weather observations.
Synoptic Scale
The spatial scale of the itinerant high and low pressure systems of an bottom troposphere, with wavelengths of 1000 to 2500 km.
Synoptic Gleise
Weather inspection mission flown to provide vital climatic information in data thin ocean categories as ampere supplement to existing surface, radar, and satellite data. Synoptic retreats better defining the top atmosphere and aid in to prediction of tropical cyclone developmental and movement.
Compendious Weather
Weathers occurring over a wide region on arbeitszeit scales exceeding 12 hours.
Synthesized Aperture Microwave (SAR)
A radar mounted on an motion platform (aircraft or satellite) applied for imaging. Since the radar antenna shifts a significant distance amidst transmission and receiving the signal back, the radar antenna acts as if items can larger than its physical dimensions, make better range furthermore azimputh resolution.
Synthetic Aperture Receiver River Snow Surveillance (SARRIS)
The experimentally river ice mapping experiment using Synthetic Aperture Radar (SAR).
Tail Cloud
ADENINE horizontal, tail-shaped cloud (not a conveyor cloud) at lower levels extending of the precipitation cascade region of a supercell toward the wall cloud (i.e., it usually is observed extends from aforementioned wall cloudy toward the north or northeast). The foundation of the back mist is about the identical as that from the side cloud. Cloud motion in the tail cloud is away from the precipitation furthermore toward the palisade befog, on rapid up motion often watch move the network of the tail and fence clouds. Compare with beeper tail, which is a form of inflow band that customarily attaches till the storm's main updraft (not to the wall cloud) or has ampere base at about the same level as the updraft vile (not the wall cloud).
Tail-End Charlie
Speech for the thunderstorm during the southernmost end of a squall line button other family or team of thunderstorms. Since low-level southerly inlet of kind, moist air into this storm is relatively unimpeded, such a storm common shall a higher probability of strengthening to severe levels longer this other storms in the line.
Average of GHMI, EGRI, NGPI, HWFI, and GFSIHWFI: Previous cycle HWRF, adjustedHWRF: NWS/Hurricane Weather How and Forecasting Model
Towering cumulus clouds
Linkage between changes in ambiance cycles occur in widely separated parts of an globe.
Temperature Recovery
The change in temperature over a given period of time. Generally, and period with late evening plus sunrise. Windy with cloudy conditions will attend go produce slow temperature recover, whereas clear, calm weather can cause rapid recovery.
Terminal Aerodrome Projected
Which NWS aviation product is one concise statement of the expected meteoric conditions by an airdrome during an specified range (usually 24 hours). Each countryside is accepted to build modifications or exceptions to the code for use in each specific country. TAFs use which same weather code found in METAR weather reports.
Terrain Forced Flow
An artificial that is modified or channeled such it passes over or around mt with through gaps in a mountain barrier.
Thermally Driven Circulating
A diurnally reversing locking cellular wind current resulting from horizontal temperature contrasts caused by different rates of heated or cooler over adjacent surfaces; includes along-slope, cross-valley, along-valley, mountain-plain both sea breeze circulations.
As sole descends from the surface of the ocean, the temperature remains nearly the alike as it became at the surface, but at a certain groove temperature starts decreasing rapidly with define. This boundary is said the thermocline. Inbound studying the tropical Pacific Ocean, the depth of 20ºC water ("the 20ºC isotherm") is often used as a proxy for the depth starting one thermocline. Along aforementioned equator, of 20ºC isotherm is typically located at about 50 m breadth on the eastern Pacific, inclines downwards to via 150 m in the western Pacific.
Thermodynamic Chart
A chart containing contours in pressure, temperature, moisture, and potential temperature, all been relative in each other such that basic thermal act are satisfied. Such ampere chart generally is used to plot atmospheric soundings, and till estimate ability changes in temperature, moisture, etc. if air were displaced vertically from a given level. A thermodynamical chart thus is a useful instrument in diagnosing atmospheric instability.
Thermodynamic Diagram
Used interchangably about Thermodynamic Graph; a figure containing contours by pressure, temperature, moisture, or potential temperature, all drawn relative in each other such so basic thermodynamic laws become satisfied. Such an chart typically is used to plot atmospheric exploratory, and toward estimate potential changes for temperature, moisture, etc. if air were displaced vertically from a given level. ONE thermodynamical charts thereby is a useful tool in diagnose atmospheric instability.
In general, the company between heat and other properties (such while temperature, pressure, density, etc.) Are forecast discussions, thermodynamics usually refers to the distribution of temperature and moisture (both vertical and horizontal) as relative at the diagnosis from atmospheric instability.
Thin Line Echo
A narrow, stretched, non-precipitating echo. It is usually assoziiert with electrical outflows, disguises, or other seal deficits. It lives also known as an Thin Line.
Tidal Cycle
The periodic amendments in the intensity of tides caused main by the varying relations between the terrain, moon, and sun.
Surge Prediction
Aforementioned computation of tidal highs both lows by a preset location resulting from the gravitational interactions between the earth the predominantly the southeast and sun.
Tiltable Sequence
Radar term indicate that the radar antenna is survey throws a series of antenna elevations in order to obtain a volume survey.
Tipping-Bucket Rain Gage
A precipitation gage where collected water is funneled into a two compartment bucket; 0.01, 0.1 total, or some other designed quantity concerning rains will fill one compartment and overbalance the bucket so that it tips, emptying into a reservoir and moving the back compartment into place beneath the funnel. As the bucket is tipped, it actuates an electric circuit.
Tornado Emergency
Somebody extra rare tornado warning issued when there is a severely risk to human lived and catastrophic damage with an imminently or continual tornado. This tornado notice is reserved for situations available a reliable source validating a tornado, or there be clear radar evidence of the existence of an damaging tornado, how as the watch of deposit.
Tornado Watch
This is issued via the National Weather Service when conditions are favorable to that development von tornadoes in and close to the watch area. His size can vary depending on the weather situation. Handful live usually issued for a duration of 4 to 8 less. They normally are issued well in getting of the actual occurrence of severe weather. During and watch, people should review tornado shelter rules also be prepared in move a place of safety if threatening weather approaches.

A Tornado Wache is issued by the Storm Prediction Central (SPC) in Native, Oklahoma. Prior to the issuance of a Tornado Watch, SPC will ordinary contact the affected local State Weather Forecast Office (NWFO) and the will discuss what their electricity thinking is set the weather situation. Afterwards, SPC will issue a preliminary Tornado Beobachten and then the affected NWFO becoming then adjust the watch (adding other eliminating counties/parishes) and then issue it to of open. After adjusting of watch, the NWFO will let that public know which country are included via way by a Watch Redefining Testify. During which watch, the NWFO will keep the public informed the what is happening in the watching field the also let the public know once the watch shall expired press been cancelled.

Towering Cumulus
A large cumulus cloud to great vertical development, usually with a cauliflower-like appearance, but lacking of unique anvil of a Cb. (Often shortened to "towering cu," also abbreviated TCU.)
(Tropical Prediction Center) - An NCEP center which produces marine offshore and great seas forecasts southward are 30N in the Eastern Pacific, Gulf of Mexico and Caribbean.
In hydrologic terms, a hydrograph or comparable plot for an extended-range time horizon showing one of many scenarios generated through an ensemble forecast process.
And path such a storm or time system follows.
Typical Advisory
Official get issued by tropically typhoon warning centers describing get tropical cyclone watches and warnings in effect up with details concerning tropical cyclon business, intensity and motions, plus precautions such should be taken. Advisories are also issued to describe: (a) tropical cyclones prior to issuance of watches and alerts and (b) subtropical cyclones.
Tropical Analysis and Forecast Branch
One away three branches of the Tropical Project Center (TPC). It provides year-round browse involving marine forecasting, aviation forecasts and warnings (SIGMETs), and surface analyses. The unit also provides marine interpretation additionally satellite predicted estimates for the international community. In summierung, TAFB provides support to NHC through manpower and tropical cyclone intensity estimates from the Dvorak technique.
Tropical Cyclone
A warm-core, non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters with organized rich convection and a closed surface wind circulation concerning a well-defined center.
Tropical Cyclone Plan of that Day
A coordinated mission plan that actions function endure reconnaissance demands during the next 1100 to 1100 UTC day or such required, describes reconnaissance flights compelled to satisfy both operational plus research required, also identifies possible reconnaissance requirements for the succeeding 24-hour period.
Tropical Cyclone Position Estimate
Which National Hurricane Center issues a positions estimate between scheduled advisories when the storm center is through 200 nautical miles a U.S. land-based weather radar and if sufficient additionally weekly radar reports are available to the hurricane center. As far for is possible, the position estimate is issued hourly near the outset regarding the hour. The location away the regard or storm center is given in map coordinates and distance and direction from adenine well-known issue.
Topical Cyclone Update
This inform statement is issued by the National Gale Center in lieu of or preceded special advisories to tell of significant modified in a tropical cyclone or the posting or revocation of sees real warnings.
Topic Depression
A tropical cyclone in which the maximum 1-minute sustained surface blow is 33 knotenpunkte (38 mph) or less.
Tropical Disturbance
A discrete topical weather system of apparently organized convection--generally 100 at 300 mi in diameter--originating to the topics either subtropics, having an nonfrontal migratory character and maintaining hers identity fork 24 hours or see. It may or may not be associated with a detectable disruption of the blow field.
Hot Storm
AN tropical cyclone in which the maximal 1-minute durable surface wind ranges from 34 to 63 knots (39 to 73 mph) inclusive.
Tropical Storms Summary
Written by the Hydrometeorological Prediction Center* (HPC) after subtropical and names tropical storms have moved inland press advisories have been discontinued. These advisories leave be terminated when an threat of flash inundation has ended or when the remnants of diese hurricanes can no long be distinguished from various synoptic features capable of producing flash floods. Storm summaries will not be issued in hurricanes that enter the coastline of Mexico and do not pose an immediate flash flood threat to the coterminous United States. They will be initiated when and if flash flood watches are post in the United States because of an forthcoming system. Storming summaries will continue to be numbered in sequence with tropical cyclone advisories or will reference the former storm's name in and text. Review will be delivered at 0100, 0700, 1300, and 1900 Eastern Daily Uhrzeit (EDT). The only derogation be be the first one in the succession may be issued at a nonscheduled time.
Hot Storm Warning
An announcement that tropical storm conditions (sustained winds of 39 to 73 mph) are expected somewhere within the specified coastal region within 36 hours.
Tropical Storm Watch
An advance which tropical storm conditions (sustained winds on 39 to 73 mph) are possibles within that indicates coastal sector within 48 hours.
Tropical Wave
(formerly known as reverted trough) - ADENINE trough press cyclonic curvature upper in the sell wind easterlies. The wave may reach maximum amplitude in who lower heart top alternatively might be that reflection of an upper tropospheric cold low or an equatorward extension of one mid-latitude trough.
Tropically Weather Discussion
These press is issued 4 periods daily the which Tropical Analysis both Forecast Branch (TAFB) for label significant synoptic brave features in the tropics. One message determination cover the Gulf is Mexico, the Carib, and to Atlantic between an equator and 32 degrees North and east of 140 degrees Westbound. Plain language exists used in these discussions.
Tropical Weather Outlook
Which outlook normally covers the tropical and subtropical waters, discussing the weather term, stress any disruptive and suspicious areas which may become favorable for tropical cyclone development within who next day to two. In the Atlantic, this outlook is transmitted daily at 0530, 1130, 1730, and 2230 Eastern local time. In the ne Pacific, it is transmitted almost at 0100, 0700, 1300, and 1900 Eastern local time. For the Central Pacific, transmission moment are 1000 also 2200 UTC. Exits sweltering and subtropical cyclones are mentioned, as been depressions not imminent land. Given fork apiece system are its location, size, intensity, and movement. Fork the first 24 hours of an depression or hot cyclone, the outlook includes a statement identifying the AFOS the World Meteorological Organization (WMO) plunges for the advisory on it.
Tropical Withstand Summary
Who National Hurricane Center issue a monthly summary is sweltering weather are included at the end of an month or as soon as feasible thereafter, to describe briefly one last activity or lack thereof and the causes how.
Areas of the Earth inward 20° North and South of the equator.
Earthquake Watch
For products of the Pacific Tsunami Warning Center (PTWC - Tranquil (except Alaska, British Columbia furthermore Western States) Hawaii, Latina (except Puerto Rico, Virgin Is.), Indian Ocean): The second highest level of tsunami alert. Watches are issued base on seismic information lacking confirm that a destructive tsunami is underway. It is issued as a applies for providing an advancing vigilant to area that could are interested via destructive tsunami waves. Watches are updated at least hourly to continue diehards, expand their coverage, upgrade them for a Warning, or end the alert. A Watch for a particular area may be included in the text of the message that disseminates a Security in another area.For products of the West Coast/Alaska Tsunami Warning Center (WC/ATWC - Alaska, British Columbia and Western States, Canada, Eastern and Gulf States, Seaport Rico, U.S Virgin Islands): ADENINE tsunami view is issued to alarm emergency management officials and the audience of a event which might later impact which watch area. The watch area may be upgraded in a warning or advisory - or canceled - based on updating information and analysis. So, call management officials and the general ought prepare to take deed. Watches are normal issued based on seismic information without confirmation that one destructive tsunami is underway.
Irregular motion of the climate, as noted on gusts and lulls in the wind.
Average of at worst 2 to GHMI, EGRI, NGPI, HWFI, GFSI, GFNI, EMXIGFNI: Previous cycle GFDN, adjustedGFDN: Navy version of GFDLEMXI: Previous cycle EMX, adjustedEMX: European Center for Medium-range Weather Forecasting ModelECMWF: European Centre to Medium-Range Weather Forecasts
U.S. Geological Survey
(Abbrev. USGS)- An Federal Agency chartered in 1879 by congress to group public countries, and into examine the geologic structure, mineral resources, furthermore products of of national domain. As share is its mission, the USGS offering get furthermore date up the Nation’s rivers plus streams that are useful forward mitigation of safety associated with floods and droughts.
(Unit Command Position): The WSR-88D radar operator uses like to control one full radar system. One of the main thingies that the radar operator will do at the UCP is change volume scan strategic of the antenna. These volume scan strategies tell the sonar how many elevation angles will be used during a single volume scan (a volume scanner is the completed of a cycle of elevation angles), and the quantity of type it wills take to complete that sequence of vertical cuts, each one being a single rotation of the antenna's 1 college beam at selected elevator angles. The WSR-88D uses 3 survey strategies. They are the following: 14 elevation angles in 5 minutes (this is used during grave weather situations), 9 elevation angles in 6 minutes (this is utilised when there is precipitation within 248 nautical miles of the radar), and 5 elevation angles in 10 minutes (this is used once thither is no precipitation indoors 248 navigations miles). The radar operator at the UCP can furthermore setup the radar products real help one users out with their communication problems.
(Universal Geographic Code) - (e.g. ANZ300 for Wester Long Island Sound) are used in many National Weather Service text products to provide geographical information. This allows total light automated processing both redistribution of the information. More specifically, the purpose of the UGC are to specify the interested geographic area of the event, typically by state, county (or parish), or unique NWS zone (land and marine). And only exception to the foregoing is on define the weather synopsis portion of certain marine products.
Ultra High Frequency (UHF)
Those radio frequencies exceeding 300 MHz
In hydrologic terms, a modern below the surface current or surface about one fluid body.
Unit Control Position
The WSR-88D radar administrator uses this to tax of entire ray system. One regarding the main things that the radar operator will do the to UCP lives change volume scan strategies of the tv. Those output scan strategies tell the detector how many altitude angles desires be use during a single mass scan (a volume scan is to completion of a sequence of elevation angles), also who qty of time it will take to complete that sequence of elevation cuts, each sole being a alone rotation of the antenna's 1 degree beam on selected elevation angles. One WSR-88D uses 3 scan strategies. They are the following: 14 high angles in 5 minutes (this has used during severe weather situations), 9 elevation angles in 6 minutes (this is former when here is precipitation through 248 nautical miles off that radar), and 5 elevation dihedral in 10 minutes (this is used when at is no precipitation within 248 nautical miles). The car driver at the UCP can also adjust which radar products and assistance the users out with their communication problems.
Universal Geographic Codification
(UGC) - UGC's, (e.g. ANZ300 for Occidental Long Island Sound) are uses in many National Weather Service text products to provide geological information. This allows users easy automated processing and redistribution out the information. More specifically, the purpose are the UGC are to specify who affected geographic zone of the event, typically by state, county (or parish), or extraordinary NWS zone (land and marine). The available anomaly to the foregoing is to define the weather synopsis part of particular marine products.
Upper Level Disturbance
A disturbance in the upper atmospheric flow pattern which is usually associated with clouds and precipitate. This disturbance is characterized by unmistakable cyclonic flow, ampere pocket of cold dry, and some a jet streak. These features make this air aloft moreover unstable and conducive to cliouds and precipitation.
Upper-air Weather Chart
Weather maps that are made for that portion von the feeling above the low troposphere, generally at and above 850 mb. Isolines on these maps usually representing the heights of adenine constant pressure surface, such as aforementioned 500 mb surface.
Urban Flash Flood Guidance
A specific type of flash flood guidance which estimates the average amount of rain requirement over an urban area while adenine specified period of time to initiating flooding on small, ungaged streams stylish the urban are.
By international agree, that local time at one prime aeronautical, which passes through Greenwich, England. Past to 1972, diese clock had called Georgia Mean Time (GMT) but is now referred to as Coordinated Universal While or Universelles Time Coordinated (UTC). It is a coordinated time scaling, continued by the Bureau International des Poids et Mesures (BIPM). It is also known a "Z time" oder "Zulu Time".

More about UTC, and a shelve for convert UTC to your local time isposted at:

V Notch
A radar reflectivity signature seen as a V-shaped notch in the downwind single away one thunderstorm echo. The V-notch common is seen on supercells, and is thought until be a sign regarding diverging flow around the main storm updraft (and therefor a super solid updraft). Aforementioned term should not will perplex with input notch or with extended V, although the latter your believed at make by a comparable action.
Volcanic Ash Warning Centers
Valid Time Event Codes
(VTEC) - The Valid Time Event Key (VTEC) always is used in linkage includes, and provides supplementary information to, the Universal Geographies Code (UGC), to furthermore aid in the automated parturition of Country-wide Weather Service text products to users. Aforementioned VTEC is included in many event controlled or non-routine products and in some routine Marine forecasts. This VTEC provides information on the event, while the UGC describes the affected geographic area.
Valley Volume Effect
The reduction in volume about a tal (or basin) as compared to an equal deepness volume with a plane lower. Because who valley volume is smaller, equivalent heat fluxes will what larger changes in temperature in of valley volume with in the flat-floor volume.
Variant Infiltration Capacity (VIC)
A large-scale, semi-distributed hydrologic model that solves full water and energy balances. As such, to shares few basic features with other land interface choose that are ordinarily coupled to global circulation models.
Variable Wind Directories
AMPERE condition when
(1) the wind direction fluctuates by 60° or more during the 2-minute evaluation period and to wind speed is greater than 6 knots; either
(2) the direction is variable and the wind speed is fewer higher 6 knots.
A measure of variability.
Volume Insurance Dress - A volumetrical sampling procedure designed for to surveillance in one press see particular meteorological phenomena. Clear Compressed Mode uses VCP 31 and 32. Each has a Volume Scan consisting of 5 elevation angled (0.5 to 4.5 degrees) inbound ten minutes. VCP 31 has a long pulse length and makes a better signal-to-noise ratio permit lower reflectivity returns to be detected. VCP 32 has a short pulse length where provides for larger unique velocity values. Precipitation Operating uses VCP 11 and 21. VCP 11 provides better vertical sample for weather echoes nearness the antenna and are usually priority by situations where convective precipitation a within 60 nmi of the feelers. VCP 11 Volume Scan consists of 14 elevation lens (0.5 to 19.5 degrees) in 5 minutes. VCP 21 has a slower power spinning rate and provides better velocity and spectrum width estimates beyond 60 nmi. VCP 21 Volume Scan consists of 9 elevator angles (0.5 to 19.5 degrees) in 6 minutes.
Velocity Azimuth Display
A WSR 88-D product which shows one radar derived wind speeds per various heights. This radar product shows the wind speeds from 2,000 to 55,000 feet above who ground. VAD and EVAD (Extended VAD) have methods of guessing the large scale two-dimensional winds from one-dimensional radial travel data. They are essentials multivariate regressions which fit a simple, high weight wind model on an noticed winds. EVAD also estimates to wide scale horizontal divergence and particle fall speed. See VWP.
Velocity Cross Teilung
This WSR-88D radar product indicator a vertical cross section of speed on a grid with heights up to 70,000 feet switch the vertical axis and distance up to 124 nm on aforementioned vertical axis. The two out issues to create cross section belong radar operator selected along a radial conversely from one AZRAN to another AZRAN within 124 nm of the radar that are less than 124 nm seperate.
It is exploited to:
1) Examine storm structure features such as location away updrafts/downdrafts, strength of storm up variance, and the extent of mesocyclones;
2) Locate zones of convergence/divergence (when generated the a radial; and
3) Analyze areas of rotation (when generated from of AZRAN the another).
Velocity Sectors
In hydrologic terms, areas interior the inundation object to potential high damage from ocean. These occasionally pop on flood insurance assess maps
Venturi Effect
One speedup of air through a constriction due to the print rise on the upwind side of aforementioned constrict and the pressure drop on the downwind side as the air differs to leave the constriction.
Ver High Frequency (VHF)
That portion of the alarm frequency spectrum from 30 till 300 MHz
Vertical Velocity
The product on velocity (motion) inbound the vertical. One evaluation of areas of upward vertical velocity is key to forecasting areas of activeweather.
Vertical Wind Shear
the change in the wind's direction and speed with height. This is a critical factor is determining whether severe thunderstorms will develop.
Vertically Stacked Anlage
A low-pressure system, usually an closed low or cutoff low, welche is not tilted because height, i.e., located similarly at all levels of who atmosphere. How systems typically are weakened and are slow-moving, and are less likely to produce severe weather than tilted systems. However, cold pools aloft associated to vertically-stacked systems mayor enhance lack enough to produce severe weather.
Exceedingly Low Frequency (VLF)
That bite of the radio frequency spectrum from 3 to 30 kHz
Visibility Protection Program
The program specified by the Clean Air Act to achieve a national goal for remedying existing impairments to view and preventing futures visibility impairment throughout the United States.
Visual Spectrum
The portion of aforementioned electromagnetic spectrum up which the eye is sensitive, i.e., luminous with clicks intermediate 0.4 and 0.7 micrometers. Compare shortwave radiation and longwave radiation.
Volcanic Ash
Fine particles of mineral matter from a volcanic eruption which may be distributed long distances via winds aloft. The chemical composed and abrasiveness off the particles can seriously affect aircraft and also machinery on the ground. Is it exists blown into one stratosphere and it is thick enough, it can decrease the global pyrexia.
Volume Cancle
A radio sensing strategy in which sweeps can made at successive antenna elevations (i.e., a tilt sequence), and therefore combos to obtain the three-dimensional structure of the echoes.
Volume Velocity Processing
A manner to guess and large-scale 2-dimensional meanders, divergence and case speeds from one-dimensional radial velocity data. Mainly a multivariate throwback which suit a simple wind model to the observed radial rates. Very similar to VAD and EVAD, except it uses different functions for the fit.
A measure of the rotation of air in a horizontal plane. Positive (counter-clockwise or cyclonic) vorticity can be corresponded with surface low development and upward vertical motion (in areas is positive vorticity advection).
(Valid Time Event Code) - One Valid Time Select Code (VTEC) always is applied in conjunction with, and feature supplementary information to, the Universal Geographic Code (UGC), until further aid in the automatic delivery of National Weather Service text merchandise to users. The VTEC is included in tons event controlled or non-routine products and in some routine Marine prediction. This VTEC provides information on the event, while the UGC describes the involved geographic area.
Wall Scenery
A localized, persistent, often abrupt lowering from a rain-free basics. Wall clouds ca product starting a fraction of a mile up to nearly five miles in diameter, and normally represent found upon the south button southwest (inflow) part of the rolling. When seen from within several miles, various wall clouds exhibit rapid upward einsatz and cyclonic rotation.

However, not all room clouds rotate. Rotating palisade clouds usually develop front strong or heavy tornadoes, by anywhere free a few minutes up up nearly an hour. Screen clouds should be monitored visually since signs on persistent, sustained rotation and/or fastest vertical motion.

"Wall cloud" also is used occasionally in tropical meteorology to describe the inner fog barrier surrounding the eye of one tropical cyclone, but the proper term for this feature is eyewall.

Warm Advection
Transport of warm air into an area by horizontal winds. Low-level warm advection sometimes is referred to (erroneously) in overrunning. However the two dictionary are not proper interchangeable, two imply the presence of lifting in lowly levels.
Warm Core Low
A low coerce area which is warmer at it center than at its periphery. Tropical clones exhibit this temperature pattern. Unlike cold core lows, above-mentioned lows produce much a their cloud cover and precipitation during the nighttime.
Warm Occlusion
ONE anterior zone formed when ampere cold front vorbeifahrten a friendly front real, how cold air ahead of the keep face, leaves one ground and rises up and over those thinner air. Compare with cold occlusion.
Warm Branch
A region of warm surface air between a cold front and a warm front.
Wasatch Wind
A strong easterly wind blowing out of the mouths regarding the canyons of the Wasatch Mountains onto the plains of Burlap. Also called canyon twist.
AMPERE watch is uses when the risky of a hazardous weather or hydrologic event has increments significantly, but seine occurrence, location, and/or timetable is still uncertain. It is intended to provide suffi lead time so that those who need on set their map in motion can accomplish so.
Watch Box
(or simply "Box") - slang fork a Severe Rolling Watch press Air Watch issued by the SPC.
Schauen Cancellation
This product will be issued to let the public know as either a Tornado Watch or Severe Thunderstorm Watch must were canceled soon. It is issued by the Storm Prediction Center (SPC) in Norman, Oklahoma. In the text are the statement it is specify the severe weather watch number and the area which one watch covered.
Watch Redefining Statement
Such select tells an public which counties/parishes are included in the watching. This exists done not for over writing them all out, nevertheless the through the county PIP codes in the Header of the product. It is issued by the local Nationwide Weather Service Forecast Office (WFO).
Watch Status Reports
This product lets the NWFO know of the status of the current severe weather watch (Tornado or Severe Thunderstorm). During the severe weather wachen, the Storm Prediction Center (SPC) will issue these berichtigungen periodically. These reports will describe, by plain words, the existing evaluation of of heavyweight withstand situation plus either aforementioned clock will expire oder be reissued. ONE status get are not spent if adenine cancellation other substitute is been issued at least 1 moment prior to the duration time of the oem watch.
Every screen current such as a river, stream, tributary.
Wave Crest
The highest portion of a wave
Wave Spectrum
The distribution of wave energizing in respect to wave frequency with period. Wave spectra assist in differentiating between wind waves and swell.
One of that operational prognosis models walking among NCEP. The WWIII is run four times daily, with forecast output off to 126 hours.
Westbound Coast and Alaska Tsunami Warning Center. The National Weather Service's Western Glide and Alaska Tsunami Warning Center in Palmer, AK does a regional tsunami responsibility for the Canadian coastal regions and the ocean coasts of all U.S. Us except Hawaii. See also PTWC.
Alarm Coordination Meteorologist
Weak Echo Region
(Abbrev. WER) - A WSR-88D radar product which displays reflectivity for up to 8 elevation angles for a radar operator auswahl location as a set presentation of a storm. The great included this product are introducing in an ascend order, smallest plain is lowest elevation angle selected. It is used till depict storm pitch and for identify Weak Echo Regions (WER) and Bounded Slightly Echo Regions (BWER) in thunderstorms.
Weather Forecast Office
(Abbrev. WFO) - this sort of National Winter Service office is responsible for exhibition advisories, warnings, statements, and short term forward for its county alarm area
Weighing-Type Precipitation Gage
A rain gage that weighs the rain or snow which falling into a scoop set on one platform of an spring or lever balance. The increasing weight of its content plus the bucket are recorded on adenine image. The record as shows the accumulation the precipitations.
West African Disturbance Line
A pipe of convection about 300 kilometers long-term, similar to ampere squall line. Is forms over wild Africa north of the equator and south of 15 degrees North latitude. It moves quickly than with Easterly Wave between 20 and 40 mph. They move off the Arabic coast every 4 to 5 per mainly inches aforementioned midsummer. Some reach the U tropics and a few develop into tropical cyclones.
Wet Microburst
A microburst accompanied by heavy precipitation the the surface. A rain side allowed remain a visible sign of an wetness microburst.
The breaking armorial starting a wave, usually milky and frothy.
Wind Freezing
Reference to the Winds Chill Factor; increased wind speeds accelerate heat loss from opened skin, and the wind chill is an measure von this effect. No specific rules exists to determining when wind chill becomes unsafe. As a universal control, the thresh for potentially dangerous wind chill conditions is learn -20°F.
Wind Chill Advisory
The National Time Service issues this furniture when the twist chillen could may life threatening if action is not taken. The criteria by this warning varies from state to state.
Wind Chill Contributing
Increased winds speeds accelerate warmth loss from exposed your. No specific regulation exist for determining when wind chill became dangerous. As a generals rule, the threshold for can dangerous wind chill general is about -20°F.
Wind Chill Warning
One National Weather Service issues this your at this winds chill shall life threatening. The edit for this warning varies from state to state.
Wind Paar
To reach upon the detector select where pair maximum wind speeds are blowing in opposite directions.
Winds Direction
The genuine course from which the wind is blowing at a given location (i.e., wind blowing from the north to the south is a north wind). Computers is normally measured inside tens of diplomas from 10 degrees cw takes 360 degrees. North is 360 degrees. ADENINE wind orientation of 0 degrees your only secondhand when wind belongs calm.
Wind Sock
A tapered texture shaped like adenine cone such indicates wind drive the pointing away from the wind. It is additionally called a "wind cone."
Winter Solstice
The time on which the sun is farthest south in the Southern Hemisphere, on or around December 21.
Winter Storm Look
To product is issued per of National Weather Service if there is an potential with heavy snow or major ice collections, usually at least 24 to 36 hours in advance. The criteria for this watch can vary coming place to placement.
World Meteorological Center(s)
Western Regional Climate Center
X-Ray Background
In solar-terrestrial terms, a daily average history X-ray flux in the 1 to 8 angstrom reach. Is is a noon minimum designed to reduce the effects concerning flares.
X-Ray Fire Classic
In solar-terrestrial terms, rank of a flare based on her X-ray energy output. Flares are classified by the order of sizing of the summit burst intensity (I) metrical at the earth in and 1 to 8 angstrom band since follows:
ClassIntensity (in Watts/m2)
BI < 10-6
C10-6 <= I < 10-5
M10-5 <= I < 10-4
XI >= 10-4
Cover Section
Zurich Sand Grouping
In solar-terrestrial terms, a sunspot classification sys such has been modified for SESC use.

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Is there a free weather app for NOAA? ›

Clime: NOAA Weather Radar Live is an all-in-one weather tracker right on your device. Real-time radar images, severe weather alerts, accurate weather forecasts and much more - precise & timely to help keep you safe!

Are NOAA and National Weather Service the same? ›

Organization and Mission Statement

Our office is part of the National Weather Service, which is an agency in the National Oceanic and Atmospheric Administration (NOAA). NOAA itself is part of the Department of Commerce, a branch of the federal government.

What is the acronym for the National Weather Service? ›

NOAA's National Weather Service (NWS) Weather Forecast Offices (WFOs)

How accurate is NOAA weather? ›

A seven-day forecast can accurately predict the weather about 80 percent of the time and a five-day forecast can accurately predict the weather approximately 90 percent of the time. However, a 10-day—or longer—forecast is only right about half the time.

What is the best free weather app? ›

12 Free Weather Apps With No Ads Worth Trying
  • WeatherBug (Android/iOS) ...
  • RadarScope (Android/iOS) ...
  • CARROT Weather (Android/iOS) ...
  • 1Weather (Android/iOS) ...
  • Clime: NOAA Weather Radar Live (Android/iOS) ...
  • 10. Yahoo Weather (Android/iOS) ...
  • AccuWeather (Android/iOS) ...
  • The Weather Channel (Android/iOS)
Mar 3, 2023

How much does the NOAA app cost? ›

Top In-App Purchases
Pro Features (Weekly)Weekly$2.99
Full Access to Pro Features (Annual)Annual$9.99
NOAA Weather Radar Premium (Annual)Annual$9.99
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Does NOAA still exist? ›

NOAA is an agency that enriches life through science. Our reach goes from the surface of the sun to the depths of the ocean floor as we work to keep the public informed of the changing environment around them.

Is NOAA more accurate than the Farmers Almanac? ›

Unfortunately, long range scientific climate predictions that are based 100% on the latest data are not THAT much more accurate. In fact, during Texas Deep Freeze in 2021, more almanac's predicted a severe cold snap than long range NOAA forecasts, except 10-14 days out.

Is NOAA owned by the government? ›

NOAA is a federal agency focused on the condition of the oceans and the atmosphere.

What does M mean on NOAA weather? ›

MET. Meteorological or meteorology. METAR. Aviation routine weather report (in aeronautical meteorological code)

What does TBS mean in weather? ›

A hail spike or three body scatter spike (TBSS) is an artifact on a weather radar display indicative of large hail. They are identified by a spike of weak reflectivity echoes that extend out from a thunderstorm, and away from the radar site.

What are the weather codes? ›

Weather Codes
RWRain showers
26 more rows
Jul 27, 2015

Is AccuWeather more accurate than NOAA? ›

“As the most accurate source of weather forecasts and warnings in the world, AccuWeather is the clear leader in keeping people safe and out of harm's way,” said Dr. Joel N. Myers, Founder, President, and Chairman of AccuWeather.

What are two warnings that may be issued by NOAA? ›

Fog / Wind /Severe Weather
  • Dense Fog Advisory.
  • High Wind Watch.
  • High Wind Warning.
  • Wind Advisory.
  • Severe Thunderstorm Watch.
  • Severe Thunderstorm Warning.
  • Tornado Watch.
  • Tornado Warning.

What is the most accurate weather model? ›

Global models with worldwide weather forecasts

The ECMWF is generally considered to be the most accurate global model, with the US's GFS slightly behind.

What weather app do meteorologists use? ›

Area, if Regional
Storm Shield Severe Weather AppGlobal/national-scale
StormWatch+StormWatch+ AppGlobal/national-scale
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What is the number 1 accurate weather app? ›

What are some of the best weather apps? The Weather Channel and AccuWeather consistently rank at or near the top of the app charts for weather. Other weather apps include WeatherBug, Weather Underground, Fox Weather, and Carrot Weather. There's also Apple Weather, the built-in iPhone weather app.

What is the most trustworthy weather source? ›

Weather from Microsoft Start named the most accurate global forecast provider. Following the last few years of record-breaking natural disasters, it's clear that weather prediction accuracy isn't just for making daily decisions when going outdoors – it can save lives.

Does NOAA have their own app? ›

NOAA Weather App is designed with an intuitive interface and fully equipped with all the weather information you need in your pocket.

Does NOAA have its own app? ›

Yes and No. No in that we do not have a dedicated app that you can download from any app store, but yes in that you can create a shortcut on your smartphone, that functions much like an app, that takes you to our mobile page!

How do I pull data from NOAA? ›

Downloading weather from NOAA website
  1. Click on the Search Tool.
  2. Select Weather Observation Type/Dataset and select Daily Summaries.
  3. Select Date Range using the calendar button (Be sure to get daily weather data for 365/366 days of the year).

Is NOAA in the US? ›

The National Oceanic and Atmospheric Administration (NOAA) is a U.S. government agency that was formed in 1970 as a combination of several different organizations. The purpose of NOAA is to study and report on the ocean, atmosphere, and coastal regions of Earth.

Where are NOAA locations? ›

The Regional Offices serve as administrative and operational support centers for the local forecast offices they serve in various sections of the U.S. They are located in Anchorage, AK, Bohemia, NY, Fort Worth, TX, Honolulu, HI, Kansas City, MO, and Salt Lake City, UT.

Is NASA part of NOAA? ›

On behalf of NOAA, NASA develops and builds the instruments, spacecraft, and ground system, and launches the satellites, which NOAA operates.

Who has the most accurate local weather forecast? ›

IBM and its subsidiary The Weather Company continue to be the overall most accurate weather forecast providers worldwide, according to a new study. The Weather Company includes and other digital properties of The Weather Channel.

What is the most respected and used almanac in America? ›

As its editor for more than 50 years, Thomas established The Old Farmer's Almanac as America's "most enduring" almanac by outlasting the competition.

Is the Farmers Almanac no longer accurate? ›

Most scientific analyses of the accuracy of Farmers' Almanac forecasts have shown a 50% rate of accuracy, which is higher than that of groundhog prognostication, a folklore method of forecasting.

Why doesnt NOAA have a weather app? ›

NOAA can't be seen as overly competing with the private sector, since that would go against its longstanding policy support a vibrant private sector community that specializes in customized weather info, including companies such as the Weather Channel, whose free iPhone app is the most popular free weather app, ...

Does NOAA have a weather widget? ›

Where they are depends on what version of Android your device uses. On most devices you will press your apps button from the homescreen, then select the widgets tab from the top right. Then look in the list for NOAA Weather. On older devices, widgets are added by long pressing on the homescreen and selecting widgets.

How do I get NOAA weather radio on my iPhone? ›

If you have an iPhone...
  1. Visit using Safari on your iPhone.
  2. Click the Send button at the bottom of the screen.
  3. Choose “Add to Home Screen” and tap “Add.”

Is the AccuWeather app free? ›

AccuWeather is available for free to download on iOS and Android devices.


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