Thursday…Downpours break by midday only to redevelop in thunderstorms, some possibly severe, toward night. Warm and humid with mixed sun this afternoon. Southwest winds increase 10 to 22 mph. Eastbound storms erupt in Iowa during the day and reach the Chicago area this evening; some storms capable of strong winds and downpours. A severe weather watch may become necessary late day or early night. Partly cloudy, windy, much cooler and less humid after the storms Thursday night.

Friday…Windy, noticeably cooler and less humid. Northwest wind gusts 35 to 40 mph at times. A sun-cloud mix. Coolest daytime high since June 8. Inland lows drop into the 40s at night.

Saturday…Mostly sunny, breezy and cool for early September. Northwest winds 8 to 18 mph, easing in the afternoon. Coolest inland lows reach the upper 40s well inland ranging to upper 50s near the lake.