A warm front surges back north through the Chicago metro area later today. Warm humid southerly flow follows on its heels Tuesday with temperatures climbing well into the 80s. With the approach of a cold front from the west Wednesday, gusty south winds will maintain high temperatures and significantly increase the chance of thunderstorms, some of which could be strong. The passing of the cold front will mark a definitive change in the upper air pattern. Starting Thursday, the western Great Lakes will come increasingly under the influence of a cut-off low pressure system aloft. A low pressure circulation breaks off from the primary jet stream flow far to the north across central Canada, drifting south and east and paralleling the U.S./Canada border. This will result in mostly cloudy skies and periodic, mostly daytime, showers over northeast Illinois. At the same time, this pattern will be responsible for strong warming over the western and eastern U.S.
--By Paul Dailey, WGN Weather Center Meteorologist
WGN-TV Chief Meteorologist Tom Skilling and the WGN Weather Center staff provide daily coverage of weather in the Chicago area.
