Weather A - Z. (U-Z)

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ICE

Weather A - Z. (U-Z)

Post #1 by ICE » Fri Apr 28, 2006 9:39 am

Unstable Air - Air that is warmer than its surroundings and tends to rise, leading to the formation of clouds and precipitation.

Veering Wind - A wind that changes its direction in a clockwise motion. For example, a west wind changing to a northwest wind.

Virga - Rain or snow that falls from a cloud but evaporates before it reaches the ground.

Visibility - The greatest distance that is possible for a person to see with their eyes. When fog occurs, a persons visibility is lowered.

Volcano - It’s any place where lave, ash or volcanic gases escape to the surface. Volcanoes come in all kinds of shapes and sizes.


Wall Cloud - It’s an area of clouds that extends underneath a thunderstorm. If a wall cloud rotates, it might form a tornado.

Warm Front - The boundary between two air masses, one cool and the other warm, moving so that the warmer air replaces the cooler air.

Warning - A forecast issued by the National Weather Service indicating that a specific weather event is actually occurring.

Watch - A forecast issued by the National Weather Service indicating that conditions are favorable for a particular weather hazard.

Water Vapor - It’s a gas in the atmosphere. There is very little of it in the air. Water vapor is only 1 to 4% of the atmosphere, but without it we would have no clouds, rain, or snow. Water vapor is one of the greenhouse gases, which help to trap the earth's heat.

Waterspout - A tornado occurring over water.

Weather - It describes the condition of the air at a particular time and place. Weather also tells how the air moves (wind) and describes anything it might be carrying such as rain, snow or clouds. Thunder, lightning, rainbows, haze and other special events are all part of weather.

Whiteout - It results from extreme blizzard conditions in which blowing snow or falling snow reduces visibility so that the sky, air, and ground becomes indistinguishable. Everything appears white and can be extremely dangerous for drivers.

Wind - The movement of air relative to the surface of the earth. It’s considered to be severe if 58 m.p.h. or greater. Hurricane winds are 74 m.p.h or greater and the highest tornado winds are about 318 m.p.h.

Wind Advisory - An advisory from the National Weather Service when the winds are between 29-38 m.p.h. lasting more than one hour, or when wind gusts are between 44-57 m.p.h.

Wind Chill - It’s the ‘feel like’ temperature on a cold day when you factor in the winds.

Wind Chill Factor - It’s a number that expresses the cooling effect of moving air at different temperatures. Only air temperature and wind speed is used in the calculation of wind chill temperatures. A wind chill temperature of 30 degrees below zero or colder on exposed skin can cause frostbite in a very short period of time.

Wind Chill Advisory - It’s issued when winds of 10 mph or greater are expected to create wind chill factors of 30 degrees below zero or more.

Windward Side - The side of an object that is facing into the direction that the wind is coming from.

Winter - The coldest season of the year. Winter officially begins in late December to late March.

Winter Storm Warning - It’s issued when hazardous winter weather is occurring or is likely over a specific area. Hazardous winter weather includes heavy snows, blizzards, ice storms, freezing rain, freezing drizzle and sleet.

Winter Weather Advisory - It’s issued for winter weather situations that could lead into hazardous conditions.


Zonal Flow - It’s when the winds in the upper levels of the atmosphere blow from coast to coast with little or no deviation. In other words, the jest stream creates a straight line.




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