WW2010
University of Illinois

WW2010
 
  welcome
 
> online guides
 
  archives
 
  educational cd-rom
 
  current weather
 
  about ww2010
 
  index

Online Guides
 
  introduction
 
> meteorology
 
  remote sensing
 
  reading maps
 
  projects, activities

Meteorology
 
  introduction
 
  air masses, fronts
 
  clouds, precipitation
 
  el nino
 
  forces, winds
 
  hurricanes
 
  hydrologic cycle
 
  light, optics
 
  midlatitude cyclones
 
> severe storms
 
  weather forecasting

Severe Storms
 
  introduction
 
> dangers of t-storms
 
  types of t-storms
 
  tstorm components
 
  tornadoes
 
  modeling

Dangers of T-storms
 
  lightning
 
  flash floods, hail
 
  outflow
 
> downbursts
 
  tornadoes

User Interface
 
  graphics
> text

NOTE: We've guessed that you're not using a client that supports colored tables and have tried to compensate. Low graphics mode looks much better on clients that do... we recommend switching to Netscape 3.0 or Microsoft Internet Explorer.
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Downbursts
severe localized downdrafts

Damaging thunderstorm winds have been termed downbursts by renowned severe storm researcher Dr. Ted Fujita. Dr. Fujita further classifies these events as macrobursts (greater than 2.5 miles in diameter) and microbursts (less than 2.5 miles in diameter).

[Image: downburst classifications (43K)]

Generally, a macroburst is on the scale of the entire cold air outflow field of a thunderstorm or a group of thunderstorms; whereas the microburst is a sub-thunderstorm scale outflow feature. This is a southward view from within one mile of a microburst embedded within a macroburst.

[Image: microburst from a dry storm (67K)]
Photograph by: Moller

The transition line from ragged to smooth cloud texture, to the left and above the microburst, is where the right to left-advancing macroburst meets cloud base. This is the leading edge of the thunderstorm gust front ahead of a line of thunderstorms. Immediately behind the gust front and to the right side of the highway, the microburst has reached ground and is in the process of "curling" over the highway. Estimated wind speeds from moving dust parcels were 70 MPH. We will have more on the visual identification of microbursts later.



outflow
Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.

tornadoes