WW2010
University of Illinois

WW2010
 
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Online Guides
 
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> reading maps
 
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Reading Maps
 
  introduction
 
  utc conversions
 
  temp conversions
 
  surface obs
 
  surface maps
 
  upper air obs
 
> upper air maps

Upper Air Maps
 
  300 mb winds
 
  300 mb temps
 
  500 mb vorticity
 
  500 mb temps
 
  700 mb humidity
 
  700 mb hum,winds
 
  700 mb vert velocity
 
  700 mb temps
 
  850 mb humidity
 
  850 mb hum,winds
 
  850 wind speed
 
  850 mb temps
 
> lifted index
 
  cape

User Interface
 
  graphics
> text

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Lifted Index
upper air data


Reference Weather Map

Current Weather Map

These panels show the most recent observations of lifted index. The lifted index is a sounding variable, meaning that it is a single value at each location, and does not change from one level to another.

The lifted index is a stability index to help measure the buoyancy of the atmosphere. Atmospheric temperature generally decreases with height. When surface air rises, it also cools. However, sometimes it cools more slowly than its surounding environment. When this happens, the rising air is warmer and less dense, and the rising air can continue to rise -- leading to storm development.

Lifted index is measured by subtracting the temperature of a surface air parcel after it has been raised to 500 mb from the atmospheric temperature at 500 mb. Meteorologists use charts to determine the temperature of the rising surface air, since they can not measure the temperature directly. This means that these calculations are made before the storms can form and be used as a forecast tool.

In analyzing lifted index, values greater than zero are not shaded. Values less than -6 are considered favorable for intense convection and possible severe weather in that location.



850 mb temps
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.

cape