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A side view of a cold front (A) and how it is represented on a weather map (B)
Click on image for full size
Windows to the Universe image by Lisa Gardiner

Cold Fronts

A cold front is where cold air is pushing into a warmer air. A cold front can cause a big change in the weather. Cold fronts are able to move up to twice as fast as a warm front.

If a cold front passes over where you live, you can notice wind, cooler air, and heavy rain from cumulonimbus clouds. Sometimes there is hail, thunder, and lightning too. Atmospheric pressure changes from falling to rising at the front. After a cold front moves through your area you may notice that the cumulus clouds are replaced by stratus and stratocumulus clouds or clear skies.

On weather maps, a cold front is shown by a solid blue line with filled-in triangles along it, like in the map on the left (B). The triangles are like arrowheads pointing in the direction that the front is moving. Notice on the map that temperatures are warmer in front of the front than behind it.

Last modified August 12, 2009 by Lisa Gardiner.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF