A Severe Thunderstorm Watch will be in effect overnight for southern and central Wisconsin as well as portions of NE Iowa and SE Minnesota until 6AM CDT Friday morning (blue-shaded counties on the headlined map). Clusters of strong to severe thunderstorms are expected to move east-southeast across central and southern Wisconsin while additional storms develop across southeast Minnesota and northern Iowa during the overnight into early morning hours Friday. Strongest storms could produce damaging wind gusts to 70 mph, two-inch diameter hail and even a tornado or two.
Storms could move out of southern Wisconsin into northern Illinois and the Chicago area during the early morning hours, and depending upon the strength of storms, the Watch area could be extended south at that time, so those potentially impacted should monitor storm activity. Note the high probability of thunderstorms within 12 miles of a given location over northern Illinois and the current Regional Weather Radar Mosaic below.