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Analyzing Precipitation Animation
closely examining each stage of development

A Closer Examination of the Animation:
Initially, a warm air mass (in yellow) nudges against a colder air mass (in blue) ahead of it, (separated from each other by the warm front). The lighter warm moist air behind the front is lifted upward and "overrides" the colder air.

[Image: air riding up and over the frontal surface (27K)]

As the air rises, it cools, and if enough water vapor condenses, widespread clouds and precipitation develop.

[Image: overrunning precipitation ahead of the surface front (23K)]

A layer of thin clouds is occasionally observed more than a thousand kilometers in advance of a surface warm front. As the front gets closer, the clouds thicken and eventually light precipitation begins to fall. Because the frontal surface gently slopes up and over the cold air mass ahead of it, the upward motions associated with warm fronts are typically not as strong as the vigorous upward motions that occur ahead of a cold front.

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.