The curl phase soon after an intense microburst impacted the surface
 Downburst damages in a straight line. (Source NOAA) A downburst is a column of sinking air that is capable of producing damaging straight-line winds of over 150 mph (240 km/h), often producing damage similar to, but distinguishable from tornadoes. This is because the physical properties of a downburst are completely opposite that of a tornado. Downburst damage will radiate from a central point as the descending column spreads out when impacting the surface, whereas tornado damage tends towards convergent damage consistent with rotating winds. Image File history File links Download high resolution version (1220x1648, 1103 KB) Summary This is a photograph of a microburst (small, intense downburst). ...
Image File history File links Download high resolution version (1220x1648, 1103 KB) Summary This is a photograph of a microburst (small, intense downburst). ...
Image File history File links Downburst_damage. ...
Image File history File links Downburst_damage. ...
The National Oceanic and Atmospheric Administration (NOAA) is a scientific agency of the United States Department of Commerce focused on the conditions of the oceans and the atmosphere. ...
A tornado in central Oklahoma. ...
A tornado in central Oklahoma. ...
Downbursts are particularly strong downdrafts from thunderstorms. Downbursts in air that is precipitation free or contains virga are known as dry downbursts; those accompanied with precipitation are known as wet downbursts. Most downbursts are less than 2.5 miles (4 km) in extent, these are called microbursts. Downbursts larger than 2.5 miles (4 km) in extent are sometimes called macrobursts. Sometimes downbursts are larger, in the extreme case, the derecho can cover a huge area of more than 200 miles wide (320 km) and over 1000 miles (1600 km) long, lasting up to 12 hours or more, and are associated with some of the most intense straight-line winds, but the generative process is somewhat different from that of most downbursts. An updraft or downdraft is the vertical movement of air as a weather related phenomenon. ...
A rolling thundercloud over Enschede, The Netherlands. ...
Virga is a meteorologic term for precipitation that falls from a cloud but evaporates before reaching the ground. ...
A photograph of the surface curl soon after an intense microburst impacted the surface A microburst is a very localized column of sinking air, producing damaging divergent and straight-line winds at the surface that are similar to but distinguishable from tornadoes which generally have convergent damage. ...
A derecho is a widespread and long-lived, violent convectively induced windstorm that is associated with a fast-moving band of severe thunderstorms usually taking the form of a bow echo. ...
The formation of a downburst starts with hail or large raindrops falling through dryer air. Hailstones melt and raindrops evaporate -- this is an endothermic process that demands a lot of energy (in form of latent heat) so the air is cooled. Cooler air has a higher density than the warmer air around it, so it falls as a "cold air balloon" (compare to hot air balloon, which rises because hot air has a lower density than the surrounding air). As the cold air balloon hits the ground, it spreads out, and a mesoscale front can be observed as a gust front. This does not cite its references or sources. ...
Rain falling Rain is a form of precipitation, other forms of which include snow, sleet, hail, and dew. ...
In Chemistry an endothermic reaction is one in which the products have more energy than the reactants, and thus a net input of energy, usually in the form of heat, is required. ...
This article or section does not cite its references or sources. ...
The term mesoscale is a size scale referring to weather systems smaller than synoptic scale systems but larger than storm-scale cumulus systems. ...
A guide to the symbols for weather fronts that may be found on a weather map: 1. ...
A gust front is a weather front that is the leading edge of gusty surface winds from thunderstorm downdrafts; sometimes associated with a shelf cloud or roll cloud. ...
A special, and much rarer, kind of downburst is a heat burst, which results from precipitation-evaporated air compressionally heating as it descends from very high altitude. Heat bursts are chiefly a nocturnal occurrence, can produce winds of up to 100 mph (160 km/h), are characterized by exceptionally dry air, and can suddenly raise the surface temperature up to 120 degrees Fahrenheit (49 degrees Celsius), sometimes persisting for several hours. A heat burst is rare atmospheric phenomenon characterized by straightline winds and a fast, high increase in temperature. ...
Downbursts, particularly microbursts, are exceedingly dangerous to aircraft which are taking-off or landing. A number of fatal crashes have been attributed to downbursts.
References
Tetsuya Theodore Ted Fujita (藤田哲也 Fujita Tetsuya, October 23, 1920–November 19, 1998) was one of the great severe storms researchers of the twentieth century. ...
Journal of the Atmospheric Sciences is a publication of the American Meteorological Society. ...
Tetsuya Theodore Ted Fujita (藤田哲也 Fujita Tetsuya, October 23, 1920–November 19, 1998) was one of the great severe storms researchers of the twentieth century. ...
The American Meteorological Society (AMS) promotes the development and dissemination of information and education on the atmospheric and related oceanic and hydrologic sciences and the advancement of their professional applications. ...
External links - University of Illinois WW2010 Project
- NWS JetStream Project Online Weather School
- Downburst event ~ Denton County, Texas
- Downburst event ~ Northern Wisconsin, July 4, 1977
- StormWiki
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