METEOROLOGIST JEFF HABY
The source region for Arctic (A) air is northern Canada and Siberia. Frigid and
dry air in Siberia can cross over
the North Pole and spill into the North American continent. Arctic air has the same characteristics as Polar air
except it is colder with even lower
dewpoints. This air often forms when a high-pressure area becomes nearly
stationary over Eastern Alaska, the Yukon, Siberia or northern Canada. Due to a near lack of winter solar
radiation, abundant surface snow / ice cover
and the continuous emission of radiation from the Earth's surface the air will progressively become colder and
colder. Temperatures can reach -30 degrees F to -60 degrees F. If the
jet stream becomes
meridional during the same time frame
Arctic air builds, very cold air will spread into Southern Canada and the U.S. Once Arctic air moves into the
Southern U.S. it modifies to Polar air and then eventually to modified Polar Air behind the cold front boundary.
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