The above image shows the latest severe weather outlook for today and tonight, from the SPC. Severe thunderstorms are possible anywhere within the green outlined region. The highest risk of severe storms will take place within the red outlined region. This will include an enhanced risk of tornado development as well.
The highest risk of tornado development will be located within the blue hatched region on the image below, over much of Wisconsin, southeast Minnesota, far eastern Iowa, and northwest Illinois:
Large hail and damaging thunderstorm winds can also be expected with severe thunderstorms that form today. Below are the images showing the greatest threat areas for large hail and damaging winds, respectively:
Severe thunderstorms are expected to develop by late afternoon initially across southeast Minnesota and northeast Iowa. This activity will then move and develop toward the East and Northeast into much of Wisconsin and at least northern Illinois during the evening hours.
Very large hail, damaging thunderstorm winds and tornadoes are likely with activity that forms in this region. Residents should remain on a high state of alert this afternoon and evening and be prepared to seek shelter if threatening weather approaches.
Further south, additional development is expected to take place along the cold front / dryline from central & southern Illinois into Missouri and Arkansas during the evening hours. Damaging winds and large hail will be the greatest threats in this region, however isolated tornadoes are also possible.
The southernmost portion of the dryline from southeast Oklahoma into northeast and central Texas may be the least active this afternoon and evening due to a strong capping inversion that is forecast to remain in place across the region. If, however, any isolated storms are able to develop, they will be severe with large hail, damaging winds and isolated tornadoes possible.
A better chance of thunderstorm development may occur after Midnight across this region, as the cap weakens. The chance of severe weather would diminish somewhat with the loss of daytime heating, however wind gusts and hail to severe limits would still remain a possibility even overnight from northeast Texas into southeast Oklahoma and Arkansas.