WW2010
University of Illinois

WW2010
 
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Online Guides
 
  introduction
 
> meteorology
 
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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

Modeling
 
  introduction
 
  supercells
 
> convective lines
 
  forecasting

Convective Lines
 
  convective lines
 
  squall lines
 
> 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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Nonsupercell Tornadoes
tornadoes produced from non-rotating storms

Even though supercell thunderstorms are responsible for the biggest and deadliest tornadoes, a significant number of tornadoes form under nonsupercell clouds and storms.

The left photograph below shows such an event. Notice that there are three tornadoes (there were actually five, but only three are pictured) that exist simultaneously. Modeling efforts to reproduce events like this have been successful as seen by the illustration below (right). Weightless tracer particles define the tornadoes.

[Image: (28K)] Photo by Blottman Image by Lee

These nonsupercell tornadoes (NST) are normally short-lived and weak, but from time to time can become strong enough to damage property and kill people. Because of this, researchers are investigating how a rotating entity like a tornado can be produced beneath clouds with non-rotating updrafts.

[Embedded Object: Animation (2.94MB)]


Video by Lee

The visualization above shows the NST process. There is a strong change in the horizontal movement of air at the gust front located at the surface where the color changes. The resulting shearing instability leads to the formation of many tornadoes, some of which merge with one another. The yellow columns represent the rotation of the tornadoes.

[Embedded Object: Animation (2.95MB)]


Video by Lee

Above is a closer look at the tornadoes produced in the previous animation. However, instead of marking the rotation regions in solid yellow, small weightless particles are introduced to show the wind field (red particles are sinking, green are rising).

These visualizations are from the first successful high resolution three-dimensional simulations of the NST generation process.



squall lines
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.

Forecasting