AccuWeather.com reported that thunderstorms moving through parts of the region could produce tornadoes and large hail.
Parts of the area had heavy snow.
A number of roadways in Chicago were shut down a day after the city received 5 inches of rain, the Chicago Tribune reported.
Illinois State Police said ramps to North Avenue in both directions and the westbound ramp to Lake Street from Interstate 290 were closed due to flooding.
A section of Interstate 94 was also closed and southbound traffic on I-55 was rerouted.
National Weather Service Meteorologist Matt Friedlein said Chicago wouldget more rain but not enough to "aggravate current flooding conditions."
"What we'll have out there today is plenty of cloud cover and from that some light sprinkles, maybe even some flurries this morning," he said. "It's possible there's a few actual little rain showers out there too but any amounts are likely to only be a few hundredths of an inch."
Flooding and mudslides were reported in Iowa and high winds were battering Tennessee and Alabama, AccuWeather said.
Power outages were reported in Illinois and in the Water Valley and Pilot Oak areas of Kentucky, AccuWeather said.
KMSP-TV, Minneapolis, reported that the Twin Cities had received 4 to 10 inches of snow since Thursday. Light snow and rain was expected to continue Friday, with sunshine predicted for Saturday.
Minneapolis Mayor R.T. Rybak declared Friday "Ski-To-Work-Day," WCCO-TV reported.
The day was created to promote healthy living and alternative commuting. Anyone who skis more than 3 miles to work during the day, and can prove it with a picture, will receive free entry to the UCare Tri-Loppet -- a summer festival featuring several outdoor sports, music, and food, officials said.