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

Types of T-storms
 
  storm spectrum
 
  single cell storms
 
  multicell clusters
 
  multicell lines
 
> supercells

Supercells
 
  introduction
 
  on radar
 
  schematic diagrams
 
  features
 
  variations
 
  hp supercells
 
> lp supercells
 
  multicell to supercell
 
  tornadic supercell

LP Supercells
 
> characteristics
 
  with tornado

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.
.
Low Precipitation (LP) Supercells
lacking in liquid rainfall content

At the opposite end of the supercell scale is the Low Precipitation (LP) supercell. For years, storm chasers have observed LP storms in the Plains' states, usually in conjunction with a dry line or low pressure trough dividing dry, warm air to the west from very humid air to the east. These rotating storms typically are quite small and lacking in liquid rainfall content.

[Image: diagram of LP supercell (54K)]

The radar echo rarely contains a pendant or hook, although the LP storm may have a tight reflectivity gradient at the southwest side. In many cases, the small size of the storm will not allow for adequate "beam filling", especially at moderate to long range from the radar. Therefore, the radar intensity of the small storm can be drastically underestimated.

[Image: LP supercell (46K)]
Photograph by: Doswell
This northward view of an LP storm in western Oklahoma shows both the small size and the powerful nature of the updraft. This storm was shrinking to an even smaller size at this time, which is how most LP storms meet their demise. Note that the updraft tower is scarcely any wider than the wall cloud. The storm earlier produced golf ball size hail and, although it rotated vigorously, it did not produce any tornadoes.

Low-precipitation supercells probably rarely occur, if at all, east of the Mississippi River. They frequently produce large hail, funnel clouds, and wall clouds, and occasionally spawn weak or even strong tornadoes. Radar identification of the storm as a supercell is difficult, especially at great range, because of the relatively small size and dry nature of the storm. Similar to the classic supercell, but unlike the HP storm, severe weather usually occurs in the southwest quadrant of the LP storm.

One last point of discussion for radar operators: spotters may report very wild visual sights and large hail with one of these storms while radar shows very little. Diplomacy, not disbelief, is important, for if you work severe weather in Texas, Oklahoma, Kansas, Nebraska, the Dakotas, or eastern portions of Colorado and Wyoming, you will encounter the LP supercell sooner or later.



HP Supercells
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.

with tornado