John Wheeler: Arctic air has well-known characteristics

When Arctic air is driven southward, its frigidity is usually tempered by conditions along the way.

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FARGO — When the forecast calls for Arctic air, most people immediately know what is coming. By definition, Arctic air is not just any cold air. It is air which has come to us directly from the Arctic. Specifically, this refers to air from approximately 66.6 degrees North latitude, which is about 1,000 miles north of the Canadian border and roughly 1,350 miles north of I-90. At this latitude, there is barely any daylight for most of the winter. With so little solar radiation, this air gets very cold.

When Arctic air is driven southward, its frigidity is usually tempered by conditions along the way. The speed at which it gets here and the amount of air mixing in from other regions determine its temperature once it arrives. Other important factors are snow cover and sky conditions. If Arctic air travels here under a clear sky and over deep snow it will have been warmed less by either solar or terrestrial infrared radiation.

Related Topics: WEATHER
John Wheeler is Chief Meteorologist for WDAY, a position he has had since May of 1985. Wheeler grew up in the South, in Louisiana and Alabama, and cites his family's move to the Midwest as important to developing his fascination with weather and climate. Wheeler lived in Wisconsin and Iowa as a teenager. He attended Iowa State University and achieved a B.S. degree in Meteorology in 1984. Wheeler worked about a year at WOI-TV in central Iowa before moving to Fargo and WDAY..
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