- a transition zone between a mass of warm air and the colder air it is replacing.
Origin of warm front
First recorded in 1920–25
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
- The forward edge of an advancing mass of warm air that rises over and replaces a retreating mass of cooler air. As it rises, the warm air cools and the water vapor in it condenses, usually forming steady rain, sleet, or snow. On a weather map, a warm front is depicted as a red line with half circles whose curved sides point in the direction in which the warm air is moving. Compare cold front occluded front. See illustration at front.
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