A warm front is a density discontinuity located at the leading edge of a homogeneous warm air mass, and is typically located on the equator-facing edge of an isotherm gradient. Warm fronts lie within broader troughs of low pressure than cold fronts, and move more slowly than the cold fronts which usually follow because cold air is denser and less easy to remove from the Earth's surface. This also forces temperature differences across warm fronts to be broader in scale.
Clouds ahead of the warm front are mostly stratiform, and rainfall gradually increases as the front approaches. Fog can also occur preceding a warm frontal passage. Clearing and warming is usually rapid after frontal passage. If the warm air mass is unstable, thunderstorms may be embedded among the stratiform clouds ahead of the front, and after frontal passage thundershowers may continue. On weather maps, the surface location of a warm front is marked with a red line of semicircles pointing in the direction of travel.
Read more about Warm Front: Development, Characteristics, Warm Sector, Depiction
Famous quotes containing the words warm and/or front:
“Captain Bligh: Mr. Byam, you’re up late.
Byam: It’s very warm below, sir.
Captain Bligh: I hadn’t noticed it. A true sailor can sleep in an oven, if need be, or in a keg of ice.”
—Talbot Jennings (1896–1985)
“I am less affected by their heroism who stood up for half an hour in the front line at Buena Vista, than by the steady and cheerful valor of the men who inhabit the snow-plow for their winter quarters; who have not merely the three-o’-clock-in-the-morning courage, which Bonaparte thought was the rarest, but whose courage does not go to rest so early, who go to sleep only when the storm sleeps or the sinews of their iron steed are frozen.”
—Henry David Thoreau (1817–1862)