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

Tstorm Components
 
  introduction
 
  updrafts/downdrafts
 
  wind shear
 
> outflow phenomena
 
  wall clouds

Outflow Phenomena
 
  introduction
 
> gust fronts
 
  microbursts
 
  scud clouds, virga
 
  rain foot, dust foot

gust fronts
 
> introduction
 
  visual clues
 
  more clues

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.
.
Gust Fronts
resembles the passage of a cold front

A gust front is a boundary that separates a cold downdraft of a thunderstorm from warm, humid surface air. Its passage at the surface resembles a cold front. A macroburst (damaging thunderstorm gust front) was advancing from northwest to southeast in this westward view across the West Texas prairie. Note the well-developed mammatus field under the leading anvil, and the new updrafts being lifted along the gust front.

[Image: gust front below a mammatus field (75K)]
Photograph by: Doswell

The question of whether or not new storms will form along a gust front is a difficult one to answer. If the gust front is moving quite fast and the atmospheric instability is marginal, new storms are not likely to develop. Research has indicated that low-level vertical shear profiles in the outflow field should be of equal but opposite sign of the shear in the low-level inflow air for the optimal redevelopment along the outflow boundary.

[Image: outflow boundary sand storm (64K)]
Photograph by: Doswell

A telephoto shot highlights the approach of the gust front. This complex had the appearance of a haboob, a dense sandstorm that occurs along the leading edge of outflow boundaries of desert thunderstorms in North Africa. Indeed, it was dust beneath the shelf cloud that resulted in this appearance, and the outflow was of downburst proportions.



Outflow Phenomena
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.

visual clues