The National Weather Service issued a flash flood warning for Chicago, urging 600,000 residents to take precautions. More rain is expected overnight, with storms anticipated Saturday afternoon. Residents were seen wading through knee-deep water amid the severe weather disruptions.

Funnel clouds were reported Friday morning in Illinois and there was a Flood Warning for parts of the Chicago area into the evening.

As of 12:30 p.m., heavy rain had already started to fall in some parts. A flash flood warning was in effect for DuPage and Cook County, the NWS said, with reports of "totally submerged viaducts and underpasses in the city of Chicago."