NASA Logo - Web Link to NASA.gov Vertical Line

+ Text Only Site
+ Non-Flash Version
+ Contact Glenn

Go
ABOUT NASA NEWS AND EVENTS MULTIMEDIA MISSIONS MyNASA WORK FOR NASA

A B C D E F G H I J K L M N O P R S T U V W Y Z


Words begining with "W"

W

Degrees west longitude, referenced to the Greenwich (prime) meridian.

Water Vapor (aka Moisture)

Water in a gaseous form.

Wave

  1. In electricity, a periodic variation of an electric current or voltage

     

  2. In physics, any of the series of advancing impulses set up by a vibration, pulsation, or disturbance in air or some other medium, as in the transmission of heat, light, sound, etc.

Wavelength

Physical distance of one period (wave repeat).

Weather

Atmospheric condition at any given time or place. Compare with climate.

Weather Facsimile (WEFAX)

A system for transmitting visual reproductions of weather forecast maps, temperature summaries, cloud analyses, etc. via radio waves. WEFAX transmissions are relayed by NOAA's geostationary GOES spacecraft.

Weather Terms

  • Clear: Sky cloud-free to 30 percent covered

     

  • Sunny: Sunshine 70-100 percent of the day

     

  • Partly sunny and partly cloudy: Both terms refer to 40 to 70 percent cloud cover partly sunny is used in the day; partly cloudy is used at night

     

  • Fog: A cloud on the ground. Fog is composed of billions of tiny water droplets floating in the air.

     

  • Snow: Precipitation of ice crystals

     

  • Snow flurries: Intermittent snowfall that may result in little accumulation.

     

  • Sleet: Pellets of ice that form when rain or melting snowflakes freeze while falling. (Occurs in cold weather; hail usually occurs in summer.)

     

  • Freezing rain: Rain that turns to ice on impact with the surface

     

  • Rain: Extended period of precipitation. Associated with large storm systems rather than single clouds or thunderstorms

     

  • Showers: Brief interval of rain that does not affect a large area

     

  • Squall: Fast-moving thunderstorm or line of thunderstorms that often can produce damaging winds, hail, and tornadoes

     

  • Hail: Pieces of ice that fall from thunderstorms. Hail often is composed of concentric rings of ice that form as the particle moves through wet and "dry" areas of the thunderstorm.

Weather Watch

Statement about a particularly dangerous weather system that may occur at some speclfied time in the future.

Weather Warning

Statement that dangerous weather is likely or is occurring. Take action.

WEFAX

See weather facsimile.

Willy-Willy

Australian term for tropical cyclone, hurricane.

Wind

A natural motion of the air, especially a noticeable current of air moving in the atmosphere parallel to the Earth's surface. Winds are caused by unequal heating and cooling of the Earth and atmosphere due to absorbed, incoming solar radiation and infrared radiation lost to space - as modified by such effects as the Coriolis force, the condensation of water vapor, the formation of clouds, the interaction of air masses and frontal systems, friction over land and water. etc.

The chart below is an abbreviated version of the Beaufort Wind Scale, named for the British admiral who invented it in 1805.



MPH * Description Effects


0-1	0	calm		smoke rises straight up; 
				water like mirror.
1-3  	1 	light 		air ripples on the water
4-7  	2	slight breeze	leaves rustle; small wavelets
8-12 	3	gentle breeze	leaves & twigs in motion;
				large wavelets
13-18	4	moderate breeze	small branches move
				small waves 2-4 feet.
19-24 	5 	fresh breeze   	small trees sway;
				whitecaps 4-8 feet tall
25-31	6	strong      	large branches sway
		breeze   	whitecaps 8-13 feet tall
32-38 	7 	near gale 	whole trees in motion
				waves 13 feet tall
39-46 	8   	gale    	twigs break off trees
				waves up to 16 feet tall
47-54 	9	strong gale	branches break; 
				waves up to 21 feet
55-63  10       whole gale	trees blown over;
				waves up to 26 feet.
64-73  11       storm		wide spread damage;
				waves up to 35 feet tall
74-up  12       hurricane	wide spread damage
				large ship sunk.
* Beaufort Number

Wind Chill

The wind can reduce significantly the amount of heat your body retains. The following wind chill chart does not take into account such variables as type of clothing worn, amount of exposed flesh, and physical condition, all of which would alter body heat.

wind    Temperature
speed
(mph) 35   30   25   20   15   10

  5   32   27   22   16   11    6

 10   22   16   10    3   -3   -9

 15   16    9    2   -5  -11  -18

 20   12    4   -3  -10  -17  -24

 25    8    1   -7  -15  -22  -29

 30    6   -2  -10  -18  -25  -33

 35    4    4  -12  -20  -27  -35

 40    3   -5  -13  -21  -29  -37

 45    2   -6  -14  -22  -30  -38

Simple Wind Chill Equation

Tw = TA - 1.5 x VA

where:

Tw = wind chill

TA = air temperature

VA = wind speed

For example, if the temperature is 20 degrees and the wind 30 mph:

Tw = 20 - 1.5 x 30

Tw = 20 - 45

Tw = -25 degrees F

Wind Vane

An instrument used to indicate wind direction.

Wind Vector

Arrow representing wind velocity. The arrow points in the direction of the wind. The length of the arrow is proportional to wind speed.

Wind Velocity

Vector term that includes both wind speed and wind direction.

Window

Term used to denote a region of the electromagnetic spectrum where the atmosphere does not absorb radiation strongly.

WOCE

See World Ocean Circulation Experiment.

Workstation

A "smart" computer terminal that serves as a primary scientific research tool, offering direct access to experimental apparatus, information files, internal computers, and output devices, usually connected to an external communications network.

World Ocean Circulation Experiment (WOCE)

A study of the general global circulation of the oceans. It emphasizes the measurements and understanding needed to describe and understand the circulation, to simulate it, and to predict its changes in response to climatic changes.

WWW

World Weather Watch


A B C D E F G H I J K L M N O P R S T U V W Y Z




TRC Activities

 

     First Gov Image


+ Inspector General Hotline
+ Equal Employment Opportunity Data Posted Pursuant to the No Fear Act
+ Budgets, Strategic Plans and Accountability Reports
+ Freedom of Information Act
+ The President's Management Agenda
+ NASA Privacy Statement, Disclaimer,
and Accessibility Certification

 

NASA Logo   
Editor: Tom Benson
NASA Official: Tom Benson
Last Updated: Jun 12 2014

+ Contact Glenn