With humid, unstable air overhead, temperatures warmed into the 90s and scattered thunderstorms developed Monday afternoon, as a cold front slowly sank south through the area. Highs reached 93 degrees at both O’Hare and Midway making it the 17th 90-degree day at Midway and 15th at O’Hare so far this summer – double the normal number of 90s by this date (8).
Cooler, drier air followed overnight with dew points dropping some 20 degrees back into the 50s making for a sunny, mild and much less humid day Tuesday. The Canadian-source high pressure will persist over our area Wednesday before finally moving off to the east, allowing a return of a little warmer and more humid air ahead of the next approaching low pressure system Thursday. Showers and thunderstorms will be possible later Thursday through Friday into Saturday.