Another round of heat and humidity with strong storms possible Wednesday

It looks like another round of thunderstorms will hit much of our area Wednesday with hot humid unstable air in place and an upper-air impulse set to trigger strong to severe storms mainly later in the afternoon and overnight.
Tuesday saw very warm rather humid air initially positioned overhead, but a combination of outflow from earlier thunderstorms over southern Wisconsin, and a “back-door” cold front moving south along the Lake Michigan shoreline set up a strong on-shore easterly flow that carried well inland. This strong “frontal” boundary with a 30-degree temperature differential between cool readings in the 60s and 70s along and inland of the lakefront versus highs in the middle 90s well inland triggered thunderstorms, a few of which were severe, dumping heavy flood-producing rains in excess of 2-inches at Aurora and Naperville and large hail – reaching half-dollar size north of Valparaiso.