The immediate Chicago metro area is free of thunderstorms early this evening, however, the area remains in a severe weather risk area. Satellite imagery suggests the air over northern Illinois is unstable. In particular, portions of eastern Iowa and northwest Illinois are very unstable, and new thunderstorms have begun to develop in the Sterling area, about 120 miles west of Chicago.
Temperatures in the upper 80s and low 90s lie just west and southwest of the metro area. This muggy, tropical air is expected to fuel rapid storm development across the region later this evening.
Some storms may contain strong winds, large hail, and torrential downpours. A frontal boundary left by the thunderstorm complex earlier today extends from northwest to east central Illinois. This may also provide and isolated tornado risk should strong storms develop along this boundary.