WW2010
University of Illinois

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

Tornadoes
 
  introduction
 
> useful diagrams
 
  low-level flow
 
  evolution (photos)
 
  cyclic storms

Useful Diagrams
 
> tornadic supercell
 
  mesocyclone
 
  storm evolution

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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Schematic Diagrams
comparison of tornadic and non-tornadic supercells

The difference between a non-tornadic thunderstorm

[Image: non-tornadic supercell (43K)]

and a tornadic supercell is that the latter storm's vigorous rotation and surface low pressure field cause a wave to form on the gust front.

[Image: tornadic supercell (45K)]

This allows warm, moist surface-based air to feed continually into the updraft and wall cloud. Cold air is "wrapped up" by the strong circulation and does not immediately undercut the wall cloud. Instead, the wall cloud becomes the location of extreme convergence of warm and rain-cooled air.

[Image: combination of the two (52K)]

The two previous examples are combined for comparison's sake. If the "undercut" storm is a relatively weak supercell (rather than a severe multicell storm), then the circulation is not strong enough to prevent cold outflow undercutting.



Tornadoes
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.

mesocyclone