A tornado watch has been issued until 11 p.m. Friday for Cook County and most of northern Illinois. Strong storms are expected to hit the Chicago area between 8 p.m. and midnight, the National Weather Service said.

Damaging winds, hail, isolated tornadoes, and torrential rain are possible with a string of storms approaching Chicagoland today.

Early Friday morning, torrential rain fell across Cook County. Multiple crashes were reported on Chicago roads and highways and thousands were left without power across the Chicago area.

Chicago faced a stormy weekend with severe weather threats, including hail and gusty winds, according to forecasts.

Severe thunderstorm warnings popped off in the greater Chicago area through the evening Thursday, forcing the evacuation of tens of thousands of people from the Windy City Smokeout.

The National Weather Service is warning of an ongoing threat for flash flooding in the Chicago region through Saturday.

More than a month's worth of rain fell on Chicago in 90 minutes on Tuesday evening, according to the National Weather Service (NWS). "There were numerous reports of flooded viaducts, several reports of water rescues, and a few reports of flooded basements," the NWS said.

Friday, temperatures are expected to reach the mid 80s with a 40 percent chance of heavy rain. Saturday, the chance of thunderstorms is 50 percent with highs in the upper 80s.

The opener of a four-game series between the Cleveland Guardians and Chicago White Sox has been postponed because of rain.