A rumbling, wind-whipping afternoon storm that passed directly over downtown Chicago brought the day's brutal 103-degree temperature plummeting down into the 80s, though the cool down didn't last long and Friday is still poised to break heat records.
About a half-hour after the fast-moving thunderstorm, the temperature at O'Hare International Airport had rebounded to 90 degrees.
"The Chicago area's temperatures are going to be much, much cooler this afternoon," said National Weather Service meteorologist Richard Castro. "It'll just be really warm and humid this afternoon. The lakefront actually cooled down to the upper 70s as the storm went over downtown Chicago."
Castro said the storm doesn't change the forecast for Friday when temperatures are expected to reach 103 degrees, possibly flirting with the city's longstanding record high of 105.
Despite the cool down, Chicagoans battled most of today with temperatures in the 100s.
Cynthia Vaughn, 39, started her day in a park in the East Garfield Park neighborhood, but decided to leave after an hour in the scorching heat.
"I noticed it was getting hotter and hotter really fast," said Vaughn, who later made her way to a Garfield Park cooling center.
More than a dozen people were in the Garfield Community Service Center looking for a break from the heat. Chairs lined the walls as people rested their heads and dozed off to the blare of a flat-screen TV.
Mark Brown, 59, said he'd likely stay at the cooling center all day because his Garfield Park home doesn't have air-conditioning.
"I've got the fan on (at home), but it don't do no good. It's still hot," he said. "I just want to get out of the heat."
The city's record 105-degree mark was set on July 24, 1934. Forecasts show the area could at least match that Friday before temperatures settle down into the 80s over the weekend.
As of 2 p.m., it was 103 at the official recording station at O'Hare International Airport, with a heat index of 105. Shortly after that, the storm hit and rain doused the bone-dry area. Some steamed tourists in downtown Chicago seemed to relish the sudden cool burst of rain, leisurely walking through it without umbrellas.
The high temperatures caused a roughly 50 percent jump in electricity usage on the Fourth of July, according to ComEd spokesman John Schoen. Today came close to breaking a peak electricity draw set on July 20, 2011.
"Our system is working just fine," Schoen said. "We've had no significant issues related to the heat. We've not had any heat related outages. We still have a few outages related to the July 1 storm. It's just about 400 in the western suburbs."