Third August since 1970 to open with three 90s

Temperatures head toward 94° in Chicago Wednesday. It’s only the third time since 1970 the three opening days of August have each posted a 90° high.
Thunder is to rumble over sections of the area Wednesday afternoon and evening. Early indications are the storms may affect 40 to 60% of the Chicago metro area on what promises to be the hottest and most humid day of the current hot spell. With nearly 2” evaporated water in the air above Chicago, any thunderstorms Wednesday could be prolific rain producers where they occur because they are likely to be slow movers.
Dry soils limited atmospheric moisture levels Tuesday--as reflected by low 60° dewpoints at the time of Tuesday’s afternoon 92° high. Dewpoints in the low 60s produce a moderately humid feel—but are well below the truly muggy, oppressive feeling 70°+ dewpoints which dominate the Gulf Coast region.
The result was a peak heat index of just 93° Tuesday.