National Weather Service United States Department of Commerce

Widespread rain and lightning will occur this morning across southern Wisconsin. The lightning threat will end from west to east as the rain comes to an end.
After some scattered storms during the pre-dawn hours, a line of severe storms are expected to move through southern Wisconsin after dawn. Best chances for severe weather in our area will exist along and south of a line from southern Sauk to southern Milwaukee Counties.
Storms are expected to move into southwestern WI around 8am, and then track east exiting over Lake Michigan between noon and 1pm. Gusty winds, hail, and heavy rain will be the main hazards. An isolated, brief tornado can't be ruled out along the WI/IL border.