Noticeably cooler air slicing into an unseasonably warm air mass will spark the intense thunderstorms.
The thunderstorms will erupt this afternoon from the western half of Upper Michigan to northeastern Nebraska. Areas from southern Wisconsin to eastern Nebraska and extreme northeastern Kansas will be targeted tonight. Tonight's threat zone includes the cities of Madison, Wis.; Des Moines, Iowa; and Omaha, Neb.
The strongest thunderstorms will be capable of producing strong winds and large hail. The winds could cause damage and overturn semi-trucks, while the hail threatens to break windows. An isolated tornado or two may touch down and cause destruction.
Story by AccuWeather.com Senior Meteorologist Kristina Pydynowski