BRIEF: Skilling: Polar air to stay through the weekend

Feb. 09--After an extended period of above-normal temperatures, a major shift in jet-stream winds will steer polar air across the Chicago area into Sunday. Northwest-to-north winds will be tapping a reservoir of arctic air originating from northern Canada. The cold is forecast to arrive in several waves. The first was felt Monday, as temperatures stayed below freezing most of the day. Colder air is due to arrive Tuesday, accompanied by light snow and gusty northwest winds. Readings late Monday were in the single digits upstream, across portions of the upper Midwest. Most of Chicago can expect an inch or two of snow, with heavier lake snow developing to the east, across the Michiana snow belt. A third and final surge of polar air is forecast for late Friday into Saturday.