Aeronautical Terms beginning with W
Wake turbulence
Turbulence found to the rear of a solid body in motion relative to a fluid. In aviation terminology, the turbulence caused by a moving aircraft.
Wall cloud
The well-defined bank of vertically developed clouds having a wall-like appearance which form the outer boundary of the eye of a well-developed tropical cyclone.
Warm front
Any non-occluded front which moves in such a way that warmer air replaces colder air.
Warm sector
The area covered by warm air at the surface and bounded by the warm front and cold front of a wave cyclone.
Water equivalent
The depth of water that would result from the melting of snow or ice.
Waterspout
A tornado that forms over water.
Water vapor
Water in the invisible gaseous form.
Wave cyclone
A cyclone which forms and moves along a front. The circulation about the cyclone center tends to produce a wavelike deformation of the front.
Weather
The state of the atmosphere, mainly with respect to its effects on life and human activities; refers to instantaneous conditions or short term changes as opposed to climate.
Weather radar
Radar specifically designed for observing weather. Some types are cloud detection radar and storm detection radar.
Weather vane
A wind vane.
Wedge
Same as ridge—an elongated area of relatively high atmospheric pressure; usually associated with and most clearly identified as an area of maximum anticyclonic curvature of the wind flow (isobars, contours, or streamlines).
Wet bulb
Contraction of either wet-bulb temperature or wet-bulb thermometer.
Wet-bulb temperature
The lowest temperature that can be obtained on a wet-bulb thermometer in any given sample of air, by evaporation of water (or ice) from the muslin wick; used in computing dew point and relative humidity.
Wet-bulb thermometer
A thermometer with a muslin-covered bulb used to measure wet-bulb temperature.
Whirlwind
A small, rotating column of air; may be visible as a dust devil.
Willy-willy
A tropical cyclone of hurricane strength near Australia.
Wind
Air in motion relative to the surface of the earth; generally used to denote horizontal movement.
Wind direction
The direction from which wind is blowing.
Wind speed
Rate of wind movement in distance per unit time.
Wind vane
An instrument to indicate wind direction.
Wind velocity
A vector term to include both wind direction and wind speed.
Wind shear
The rate of change of wind velocity (direction and/or speed) per unit distance; conventionally expressed as vertical or horizontal wind shear.