The most severe weather is east of the Chicago area and authorities in Lake County say the flooding situation there has improved significantly since an overnight storm soaked the area.
Kent McKenzie with Lake County Emergency Management said authorities are keeping an eye on some retention ponds, and road closures persist in some areas, but the threat to homeowners has passed.
Still, the National Weather Service has extended a flood warning for small streams until 10 a.m. Friday. Gurnee officials are warning residents of possible flooding along the Des Plaines River. According to a release from the village, as of 8:30 a.m. Thursday, the river was at 6.31 feet and rising; flood stage is 7 feet. Since midnight, the river has risen nearly 3 feet.
Northern and Central Cook were soaked to the bone overnight, with some areas seeing an inch to two inches of rain. That made for a messy Thursday morning commute.
Metra's Union Pacific North Line experienced flash flooding just north of the Waukegan station, resulting in some trains being halted and shuttle buses put into place betwen Zion and Winthrop Harbor.
There were no delays reported by Metra as of 4 p.m. The CTA and Illinois State Police were also reporting no weather-related problems.
Numerous area roads were closed earlier in the day, many of them in Lake County. Highway 41 was closed for 3 1/2 miles between Lake Bluff and Lake Forest. Authorities said they don't expect it to reopen before noon on Friday.
One overpass in the area had a clearance of 14.2 feet, and officials estimated the water was 10 feet deep. Dive teams searched the water to see if there were any occupants in three cars that were completely submerged. None were found.
More than 200 flights were canceled at O'Hare due to the weather, according to the city's Dept. of Aviation. But as of 4 p.m., due to improving visibility conditions in the area, flight delays at O'Hare and Midway had been reduced to an average of 30 minutes for all flights.
About 4,300 people lost power overnight due to heavy wind and lightning, ComEd spokesman Jeff Burdick said. By 3 p.m., only 1,100 customers remained without power, with the majority of those reported as new outages not caused by the storms.
In Chicago, 200 customers remained powerless, while 400 customers in the northern suburbs and 460 in the south suburbs remained in the dark. Thirty customers are without power in the west suburbs, Burdick said.
The majority of customers affected by the weather-realted outage had power back by 10 a.m.