WW2010
University of Illinois

WW2010
 
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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

HP Supercells
 
  introduction
 
  characteristics
 
  westward view
 
> flow field
 
  outflow boundary

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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Flow Field of Tornadic HP Supercells
inflow and outflow

A few HP storms do produce violent tornadoes. When they occur, the tornadoes often will be wrapped in precipitation and quite difficult to observe. The photographer heard a roaring sound, and ran outside where he had this westward view. Behind the super-imposed inflow arrows is a wall cloud, with a rain area and RFD wrapping from left to right around the wall cloud's southeast flank. This rain shaft is visual manifestation of the radar hook (an unusually "fat" radar hook in this case) wrapping around the wall cloud and developing tornado.

[Image: westward view of tornadic hp supercell (79K)]
Photograph by: NSSL

We are in a position of strong inflow, as noted by the northward-bending trees (in the image below). However, a gust front (blue, descending arrows) is accompanying the precipitation and approaching the photographic position. The brunt of the HP storm's precipitation area is out of the photo and to the right (northeast of the wall cloud).

[Image: tornado hidden by rain curtain (80K)]
Photograph by: NSSL

Still hearing a roaring sound, the photographer shifted his view a bit towards the northwest. Almost hidden behind the advancing rotating rain curtain is a large and devastating tornado!

[Image: tornado visible through precipitation (77K)]
Photograph by: NSSL

The rain curtains that wrap around an HP supercell's tornado often change very quickly in appearance. Minutes later, the tornado is not quite as obscured by the precipitation. View these three slides a second time and observe the advance of the rain curtain and gust front. The tornado was continuing to receive a narrow corridor of inflow from the northeast at this time, as it approached Drumwright, Oklahoma. Fourteen people were killed by this violent 1974 tornado.



westward view
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.

outflow boundary