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

Air Masses, Fronts
 
  introduction
 
  air masses
 
> fronts
 
  advection

Fronts
 
  introduction
 
  stationary front
 
> cold front
 
  warm front
 
  occluded front
 
  dry line

Cold Front
 
  definition
 
  wind shift
 
> lower dew points
 
  cyclones
 
  precipitation

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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Finding Cold Fronts Using Dew Points
lower dew point temperatures behind the cold front

Another indication of a possible frontal passage is a change in the air's relative humidity. The air mass ahead of a cold front is typically more moist than the air mass behind it. The surface map below contains reports of temperature, dew point temperature, and wind barbs. Higher dew points indicate a higher moisture content of the air. Ahead of the cold front analyzed below, dew point temperatures were generally in the 50's, while behind the front, dew point values dropped off into the 30's and 40's.

This decrease in dew point temperature indicated the presence of drier air behind the cold front. A noticeable change in the air's relative humidity is commonly observed with the passage of a cold front. Before the front arrives, the air typically feels more humid (in the warmer air mass), but once the front passes through, the humidity decreases and the air feels drier.



wind shift
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.

cyclones