WW2010
University of Illinois

WW2010
 
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Online Guides
 
  introduction
 
> meteorology
 
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Meteorology
 
  introduction
 
  air masses, fronts
 
  clouds, precipitation
 
  el nino
 
  forces, winds
 
  hurricanes
 
  hydrologic cycle
 
  light, optics
 
  midlatitude cyclones
 
  severe storms
 
> weather forecasting

Weather Forecasting
 
  introduction
 
  methods
 
> surface features
 
  temperatures
 
  precipitation

Surface Features
 
  anticyclones
 
  cyclones
 
> cold fronts
 
  warm fronts
 
  stationary fronts
 
  occluded fronts
 
  dry lines

User Interface
 
  graphics
> text

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Cold Fronts
colder temperatures and possibly precipitation

A cold front is defined as the transition zone where a cold air mass is replacing a warmer air mass. In the example below, temperatures ahead of the cold front are 55 and 62 degrees while behind the front, the temperatures are lower, 31 and 28.

The air mass behind a cold front is likely to be cooler and drier than the one before the front. If a cold front is approaching, precipitation is possible just before and while the front passes. Behind the front, expect clearing skies, cooler temperatures, and lower relative humdities.

The picture below is a vertical cross-section depicting the development of precipitation ahead of and along cold front. The blue mass represents the colder air behind the cold front (solid blue line) and the yellow areas indicate the warm moist air mass ahead of the front.

[Image: snapshot of thunderstorms ahead of cold front (27K)]

As the cold air mass propagates, it lifts the warmer less dense air ahead of it (red arrows). The air cools as it rises and the moisture condenses to produce clouds and precipitation ahead of and along the cold front. In contrast to lifting along a warm front, upward motions along a cold front are typically more vigorous, producing deeper clouds and more intense bands of showers and thunderstorms. However, these bands are often quite narrow (a couple hundred kilometers across) and move rapidly just ahead of the cold front.



cyclones
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.

warm fronts