Weather terms starting with W

143 terms

W West
WAA Warm Air Advection - the advection (movement) of warm air into a region.
Wake The region of turbulence immediately to the rear of a solid body caused by the flow of air over or around the body.
Wall Cloud A localized, persistent, often abrupt lowering from a rain-free base. Wall clouds can range from a fraction of a mile up to nearly five miles in diameter…
Warm Advection Transport of warm air into an area by horizontal winds. Low-level warm advection sometimes is referred to (erroneously) as overrunning.
Warm Core Low A low pressure area which is warmer at its center than at its periphery. Tropical cyclones exhibit this temperature pattern.
Warm Front A transition zone between a mass of warm air and the colder air it is replacing.
Warm Occlusion A frontal zone formed when a cold front overtakes a warm front and, finding colder air ahead of the warm front, leaves the ground and rises up and over…
Warm Sector A region of warm surface air between a cold front and a warm front.
Warning The fourth of five Early Warning System components consisting of the processes (including the media) and equipment necessary to make the public aware of…
Wasatch Wind A strong easterly wind blowing out of the mouths of the canyons of the Wasatch Mountains onto the plains of Utah. Also called canyon wind.
Wastewater Water that typically contains less than 1% concentration of organic hazardous waste materials.
Watch A watch is used when the risk of a hazardous weather or hydrologic event has increased significantly, but its occurrence, location, and/or timing is still…
Watch Box (or simply "Box") - slang for a Severe Thunderstorm Watch or Tornado Watch issued by the SPC.
Watch Cancellation This product will be issued to let the public know when either a Tornado Watch or Severe Thunderstorm Watch has been canceled early.
Watch Redefining Statement This product tells the public which counties/parishes are included in the watch.
Watch Status Reports This product lets the NWFO know of the status of the current severe weather watch (Tornado or Severe Thunderstorm).
Water Equivalent The amount of water, in inches, obtained by melting a snow sample.
Water Pollution The alteration of the constituents of a body of water by man to such a degree that the water loses its value as a natural resource.
Water sky Water sky The dark appearance of the underside of a cloud layer when it is over a surface of open water.
Water Supply Outlook A seasonal volume forecast, generally for a period centered around the time of spring snowmelt (e.g., April-July).
Water Table The upper level of ground water; the level below which soil and rock are saturated with water.
Water Vapor The most abundant greenhouse gas, it is the water present in the atmosphere in gaseous form.
water vapor path A measure of the total amount of water vapor present in the column. A retrieved quantity from the microwave radiometer.
Water Vapor Plume This appears in the water vapor satellite imagery. It is a plume-like object that extends from the Intertropical Convergence Zone (ITCZ) northward or…
Water Year The time period form October 1 through September 30.
Watercourse Any surface flow such as a river, stream, or tributary.
Watershed All land area from which run-off water may enter a pond or lake.
Waterspout In general, a tornado occurring over water. Specifically, it normally refers to a small, relatively weak rotating column of air over water beneath a Cb or…
Watt The rate of energy transfer equivalent to one ampere under an electrical pressure of one volt. One watt equals 1/746 horsepower, or one joule per second.
Wave Crest The highest part of a wave
Wave Height Distance from wave trough to wave crest.
Wave Period Time, in seconds, between the passage of consecutive wave crests past a fixed point.
Wave Spectrum The distribution of wave energy with respect to wave frequency or period. Wave spectra assist in differentiating between wind waves and swell.
Wave Steepness The ratio of wave height to wavelength and is an indicator of wave stability. When wave steepness exceeds a 1/7 ratio; the wave typically becomes unstable…
Wave Trough The lowest part of the wave.
Wavelength The distance between one peak or crest of a wave (of light, heat, or other energy) and the next corresponding peak or crest.
WAVEWATCH III One of the operational forecast models run at NCEP. The WWIII is run four times daily, with forecast output out to 126 hours.
Waxes Solid or semisolid materials derived from petroleum distillates or residues. Light-colored, more or less translucent crystalline masses, slightly greasy…
WBND Westbound
WBZ Wet Bulb Zero - the height where the wet-bulb temperature goes below 0°C. It is important because WBZ heights between 7000 ft and 10,500 ft (above ground…
WC/ATWC West Coast and Alaska Tsunami Warning Center. The National Weather Service's West Coast and Alaska Tsunami Warning Center in Palmer, AK has a regional…
WCM Warning Coordination Meteorologist
WDIR On a buoy report, wind direction (the direction the wind is coming from in degrees clockwise from true N) during the same period used for WSPD.
WDLY Widely
WDSPRD Widespread
Weak Echo Region (Abbrev. WER) - A WSR-88D radar product which displays reflectivity for up to 8 elevation angles for a radar operator selected location as a set…
Weather The state of the atmosphere with respect to wind, temperature, cloudiness, moisture, pressure, etc.
Weather Forecast Office (Abbrev. WFO) - this type of National Weather Service office is responsible for issuing advisories, warnings, statements, and short term forecasts for its…
Weatherfax See RADIOFACSIMILE
Wedge Tornado Slang for a large tornado with a condensation funnel that is at least as wide (horizontally) at the ground as it is tall (vertically) from the ground to…
WEFAX System for transmitting weather charts and imagery via satellite. Occasionally used as an abbreviation for radiofacsimile via HF radio.
Weighing-Type Precipitation Gage A rain gage that weighs the rain or snow which falls into a bucket set on a platform of a spring or lever balance.
Weir An overflow structure built across an open channel to raise the upstream water level and/or to measure the flow of water.
WER Weak Echo Region - Radar term for a region of relatively weak reflectivity at low levels on the inflow side of a thunderstorm echo, topped by stronger…
West African Disturbance Line A line of convection about 300 miles long, similar to a squall line. It forms over west Africa north of the equator and south of 15 degrees North latitude.
West Wall The coast side boundary of the Gulf Stream, typically south of Cape Hatteras. See also North Wall
Westerlies The prevailing winds that blow from the west in the mid-latitudes.
Wet Bulb Zero (Abbrev. WBZ) - the height where the wet-bulb temperature goes below 0°C. It is important because WBZ heights between 7000 ft and 10,500 ft (above ground…
Wet Floodproofing An approach to floodproofing which usually is a last resort. Flood waters are intentionally allowed into the building to minimize water pressure on the…
Wet Microburst A microburst accompanied by heavy precipitation at the surface. A rain foot may be a visible sign of a wet microburst.
wet-bulb depression The difference in degrees between the air temperature (dry-bulb temperature) and the wet-bulb temperature.
Wet-Bulb Temperature The lowest temperature that can be obtained by evaporting water into the air.
Wetland Area covered all or part of the year by water. Can be identified by typical plants and soil types.
Wetlands Area having specific hydric soil and water table characteristics supporting or capable of supporting wetlands vegetation.
WFO Weather Forecast Office - this type of National Weather Service office is responsible for issuing advisories, warnings, statements, and short term…
WFP Warm Front Passage
Whirlwind A small, rotating column of air; may be visible as a dust devil.
White Light (WL) Sunlight integrated over the visible portion of the spectrum (4000 - 7000 angstroms) so that all colors are blended to appear white to the eye.
White Light Flare In solar-terrestrial terms, a major flare in which small parts become visible in white light.
Whitecap The breaking crest of a wave, usually white and frothy.
Widespread Areal coverage of non-measurable, non-convective weather and/or restrictions to visibility affecting more than 50 percent of a forecast zone(s).
Wildfire Any nonstructural fire that occurs in the wildland.
Wildlands Any nonurbanized land not under extensive agricultural cultivation, e.g., forests, grasslands, rangelands.
Willy-Willy A tropical cyclone of hurricane strength near Australia.
Wind The horizontal motion of the air past a given point. Winds begin with differences in air pressures.
Wind Advisory Sustained winds 25 to 39 mph and/or gusts to 57 mph. Issuance is normally site specific.
Wind Chill Reference to the Wind Chill Factor; increased wind speeds accelerate heat loss from exposed skin, and the wind chill is a measure of this effect.
Wind Chill Advisory The National Weather Service issues this product when the wind chill could be life threatening if action is not taken.
wind chill equivalent temperature The apparent temperature felt on the exposed human body owing to the combination of temperature and wind speed.
Wind Chill Factor Increased wind speeds accelerate heat loss from exposed skin. No specific rules exist for determining when wind chill becomes dangerous.
Wind Chill Warning The National Weather Service issues this product when the wind chill is life threatening. The criteria for this warning varies from state to state.
Wind Couplet An area on the radar display where two maximum wind speeds are blowing in opposite directions.
Wind Direction The true direction from which the wind is blowing at a given location (i.e., wind blowing from the north to the south is a north wind).
Wind Field The three-dimensional spatial pattern of winds.
Wind Gust Rapid fluctuations in the wind speed with a variation of 10 knots or more between peaks and lulls.
Wind Radii Term used in National Weather Tropical Cyclone Forecast Advisory products (TCM).
Wind Rose A diagram that indicates the average percentage of time that the wind blows from different directions, on a monthly or annual basis.
Wind Shear The rate at which wind velocity changes from point to point in a given direction (as, vertically).
Wind Shear Profile The change in wind speed and/or direction usually in the vertical. The characteristics of the wind shear profile are of critical importance in determining…
Wind Shift A change in wind direction of 45 degrees or more in less than 15 minutes with sustained wind speeds of 10 knots or more throughout the wind shift.
Wind Shift Line A long, but narrow axis across which the winds change direction (usually veer).
Wind Sock A tapered fabric shaped like a cone that indicates wind direction by pointing away from the wind. It is also called a "wind cone."
Wind Speed The rate of flow of the wind undisturbed by obstacles.
wind vane An instrument used to determine wind direction.
Wind Waves Local, short period waves generated from the action of wind on the water surface (as opposed to swell). Commonly referred to as waves.
windsock A large, conical, open bag designed to indicate wind direction and relative speed; usually used at small airports.
Windward The side toward the wind. Compare with leeward.
Windy 20 to 30 mph winds.
WINT winter