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Thunderstorms are expected to fire up Friday in the Chicago area, and some could be strong or even severe. Will they snarl your weekend plans?
About 11 a.m., Live Doppler 5 radar showed some showers already developing across multiple Chicago suburbs. Over the border in Wisconsin, heavy rain and storms were passing over Milwaukee.
In Illinois, an isolated thunderstorm was possible between 2 and 3 p.m., NBC 5 Storm Team Meteorologist Pete Sack said, though the main event expected to come later in the evening.
“It looks as though the severe weather window will open up at 3 p.m. at the very earliest, until midnight at the very latest,” Sack said. “Main area of storms looks to arrive between 7 and 10 p.m.”
A severe thunderstorm warning was in place for southwestern McHenry counties until 3 p.m. Another warning was issued for northern DeKalb and west central Kane until 4 p.m.
Meanwhile, much of the region was under a severe thunderstorm watch until 10 p.m. CT. That includes:
Illinois
- DeKalb
- LaSalle
- Cook
- DuPage
- Grundy
- Kane
- Kankakee
- Kendall
- Lake
- McHenry
- Will
Indiana
- Lake
- Newton
The Storm Prediction Center has placed the entire Chicago area under a “slight” risk of severe weather, which ranks as level two of five. Damaging winds, large hail, heavy downpours and even an isolated tornado were all possible, Sack said, which could hit right as outdoor events take place.
“If you hear thunder, you can be struck by lightning,” Sack said. “So especially at those football games, head to your car waited out in the car. That’s the best place as we see these storms roll their way on through.”
The greatest tornado and severe weather threat lies west of the Fox Valley and north of I-80, the National Weather Service said.
(🧵1/2) Scattered thunderstorms are expected this afternoon and evening. A few storms may become severe with damaging winds and large hail the main threats. Be sure to have multiple ways to receive warnings! #ILwx #INwx pic.twitter.com/icLIIpdKtd
— NWS Chicago (@NWSChicago) August 21, 2026
After showers and storms move through, temperatures will drop down into the low 60s across the area, Sack said, with temperatures in the 70s for both weekend days.
Saturday starts out quiet and dry, Sack said, but an isolated thunderstorm or two could develop starting about 3 p.m. in parts south and west of the city.
“As we go into the evening timeframe, those storms will dissipate,” Sack said.
