WW2010
University of Illinois

WW2010
 
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> online guides
 
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Online Guides
 
  introduction
 
> meteorology
 
  remote sensing
 
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  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

Modeling
 
  introduction
 
> supercells
 
  convective lines
 
  forecasting

Supercells
 
  introduction
 
> structure
 
  tornadoes

User Interface
 
  graphics
> text

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Supercell Structure

Supercells have a common structure, as can be seen by the left diagram below. Computer model visualizations (below right) can capture most of this structure.

[Image: (32K)] [Image: (22K)] Image by NCSA/Wilhelmson
Click image for video (Must have RealPlayer G2)
Supercells are characteristically tall storms -- reaching way up into the stratosphere. The main updraft and downdraft mutually support one another leading to a long lasting storm. Click on the image below to explore a 3D severe storm through VRML.


Click to explore VRML Storm (11MB).

Click to explore VRML Storm.
Often, if you can see the whole storm, you can see a large dome above the central updraft and a broad, flat region covering the entire storm and extending downwind of the updraft. This is called the anvil, and both features show up well in this model. [Image: (22K)]
Image by NCSA/Wilhelmson
[Image: (27K)]
Image by NCSA/Wilhelmson
Another characteristic observable in both models and in nature is the large cloud free area above the base of the updraft known as the vault or Weak Echo Region. Rain and possibly hail fall to the ground outside this region, leaving the vault region relatively precipitation-free.
In some supercells, one can sometimes observe both a v-notch and a hook echo. In this modeled radar image, both are evident. A hook echo is a strong signal that a supercell thunderstorm is about to or already has produced a tornado.
Image by NCSA/Wilhelmson

Click for VRML flanking line
Some supercell thunderstorms also possess a clearly visible flanking line. The flanking line separates cool storm outflow from warm moist storm inflow and sits above the gust front. New storms form along the flanking line as the moist inflow air rises as it approaches the cool surface air. In this VRML environment, the blue body represents areas of significant cloud development with the flanking line very evident (foreground of image).
Weightless particles are used to trace the air motion within a supercell. Blue balls are sinking and orange balls are rising. [Image: (38K)]
Image by NCSA/Wilhelmson



introduction
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