High temperatures Thursday occurred just after midnight, with afternoon readings in the 60s area-wide. It has been over three months since we've had an afternoon that cold. Afternoon highs in the upper 60s were 20 to 25 degrees cooler than Wednesday's readings that peaked in the lower 90s.
With Canadian-source high pressure centered over the northern Great Lakes and a quasi-stationary frontal system to our south along the Ohio River Valley, northeast to east winds will continue over the Chicago area through the coming weekend. With lake water temperatures in the 60s, highs each day will struggle to reach the 70-degree mark.