With a warm humid rather unstable air mass in place and a short-wave upper-air disturbance moving over our area, conditions are ripe for scattered showers and a few potentially strong thunderstorms in the Chicago area this afternoon.
The National Storm Prediction Center has the Chicago area in a Slight Risk of severe storms (green-shaded area on the headlined map depicting a 5% chance of severe storms within 25 miles of a given location). Strongest storms are likely to occur just south of Chicago and east of Interstate-55 into NW Indiana.
Brief heavy rains, lightning, winds gusting in excess of 40 mph and possibly some large hail could accompany strongest storms. As the upper disturbance moves east, showers/thunderstorms should end from the west late afternoon/early evening.