Chilly showers, then a taste of summer

Air of Canadian origin blasts across Chicagoland late today, initiating a temperature plunge that will culminate in a 28° drop by Thursday morning.
Air aloft will chill also, with readings a mile above the area hovering just above freezing through the day on Thursday, thereby establishing a vertical temperature differential sufficient to generate lake-effect rain showers. Borne along by brisk winds blowing from the north or northeast, those showers may dampen the area on Thursday. Were this early or mid winter, a similar situation would likely result in a significant lake-effect snow event.
It’s to be a short-lived cool spell. Winds, surface and aloft, turn westerly and then southwesterly by Saturday, and temperatures respond.
Area readings push toward 70º on Sunday, merely a prelude to a more vigorous warm surge on Monday that carries the city’s temperatures well into the 80s.
-Richard Koeneman WGN-TV Meteorologist