CHICAGO — The National Storm Prediction Center continues to have northern Illinois, southern Wisconsin, eastern Iowa and northwest Indiana under a Slight Risk of severe thunderstorms this Thursday afternoon/evening (yellow-shaded area on the highlighted map). The primary risk here will be damaging winds, although large hail may occur along with locally heavy flood-producing downpours. Isolated tornadoes cannot be ruled out, but have a better chance of occurring in southern Wisconsin.
A center of low pressure will intensify as it moves out of Iowa into Wisconsin today, and the associated cold front is projected to swing out of Iowa across Illinois this afternoon into Indiana tonight. Strong to severe thunderstorms are expected to develop along and in advance of the approaching cold front. Much cooler Canadian-source high pressure will follow on the wings of west to northwest winds later tonight and Friday.