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05/17/2005 - Updated 09:17 AM ET
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More about anafronts

A cold front breeds more precipitation when weak upper-level winds relative to stronger surface winds stretch the cold front out and the slope of the cold air becomes much less. This usually occurs when the upper-level winds become parallel to the front.

Warm, moist air ahead of the front overruns the colder air at the surface due to the weak upper-level winds. Clouds and precipitation form well behind the leading edge of the cold air at the surface. In some cases, clouds and precipitation can extend more than a 1,000 miles behind the surface front. Cold fronts that undergo this process and bring significant clouds and precipitation behind the surface front are known as "anafronts."

Ana- is a prefix of Greek origin meaning to ascend or move upward. An "ana-" cold front has warm air ascending the cold frontal surface to high altitudes where the moist air condenses into clouds and rain or snow. In some instances, anafronts might stall over a particular location and bring a week or more of wet weather.

By Chad Palmer, USA TODAY Weather team

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