For the second time this month, a strong line of thunderstorms knocked out power to more than 300,000 ComEd customers and wrecked havoc on tree limbs across the suburbs.
The storms, which whipped through the region early Tuesday morning, produced wind gusts of up to 70 mph in some areas such as Naperville in DuPage County and Elburn in Kane County.
As of 7 a.m. Wednesday, about 16,000 customers remained without power, and some of those might not be back up and running until Thursday night, according to a ComEd spokeswoman.
About 4,000 customers remained without power in the western region as of 7 a.m., while 1,500 were without power in the northern region, 5,000 in the southern region and 5,500 in the Chicago region, said company officials.
As of 7 a.m., ComEd had restored power to more than 300,000 customers, officials said.
The west and north regions cover the counties of Lake, Cook, DuPage, Kane and McHenry counties.
Officials from the Chicago Department of Aviation said about 115 flights were canceled at O'Hare International Airport Tuesday, and both O'Hare and Midway passengers faced delays throughout the day.
The storm rolled through just three weeks after a front knocked out power to more than 300,000 ComEd customers on July 1. Thousands who lost power during that storm, were without electricity through the Independence Day holiday.
Officials said the worst locations struck by Tuesday morning's storm were in DuPage County, where numerous tree limbs and wires were knocked down.
Aurora spokesman Dan Ferrelli said the 911 center handled about 215 calls in 40 minutes during the height of the storm, and that the city of Aurora has 30 employees cleaning up the mess.
"I think this one's bark was a little worse than its bite," said Bensenville public works Director Joseph Caracci, comparing the two July storms.
Although there is only a 20 percent chance of showers and a possible thunderstorm today, the severe weather is not expected to let up, as temperatures are predicted to reach highs around 100 degrees, according to the National Weather Service.
A Heat advisory is in effect from 11 a.m. until 10 p.m. today with afternoon heat index readings expected to reach between 102 to 107.
• Daily Herald staff writer Hannah Meisel contributed to this story.