CHICAGO — Scattered storms are possible Wednesday.
Daytime heating will drive the precipitation development meaning the most widespread rains will occur in the warmer hours of the day from late morning in to afternoon. But areal coverage of the showers and thunderstorms appears likely to impact perhaps 20 to 30% of the metro area.
Before the rain arrives, there will be stronger sunshine, compared to recent days, meaning you can suffer a sunburn quickly this afternoon.

Showers and storms start to bubble up around noon south of I-80.
Rain showers will start in the metro area around 2 p.m.
Full forecast details and more at the WGN Weather Center blog
But once the sun sets, daytime heating goes away and takes with it the chance for rain.
It will return again on Thursday though, likely in the afternoon hours.

Friday will be quieter weather-wise.