The seasons haven't flipped from Spring to Autumn, but it sure will feel like it in the Upper Midwest and Great Lakes. A late-season freeze is possible in parts of Michigan and Wisconsin early Friday.

A chilly air mass with roots in northeastern Canada has settled across the Upper Midwest and western Great Lakes. This is producing a chilly but sunny Thursday for Chicago, Green Bay and Detroit.

Tonight, a clear sky and calm winds will allow the temperatures to plummet, with lows dropping into the 30s and 40s. Across northern Michigan and northern Wisconsin, the temperatures could drop below freezing, which could damage or kill sensitive plants.

These temperatures are 10 to 15 degrees colder than normal. The TemperatureRadar shows warmer weather returning Friday, even as the colder air mass settles into the Mid-Atlantic and Northeast.