A day after major flooding hit the Northwest suburbs, another storm front moved through the area around rush hour bringing strong winds, hail and traffic backups.
The storm passed quickly, snarling transportation and creating more power outages.
A flood warning is in effect through 1:45 p.m. on Friday with more the possibility for more thunderstorms in the forecast.
As of 10 p.m. about 21,000 people were without power in Cook County and about 200 each in DuPage, Lake and Kane counties, according to ComEd.
O'Hare International Airport instituted a ground stop during the storm and flights were operating at least an hour behind schedule.
Aside from the storms, a switching issue on Metra created major delays on some lines of more than an hour as well causing more travel headaches on Thursday evening. The lined effected were Milwaukee District North, Milwaukee District West, North Central Service, Union Pacific Northwest, West and North, according to Metra.