Chicago Weather Alert: Severe Storms Tonight Could Bring Flash Floods—Here’s What to Know

Chicago residents are bracing for a one-two punch of oppressive heat and fast-moving thunderstorms as a sizzling Saturday unfolds across the metro area. Temperatures surged into the mid-90s by mid-afternoon, and the heat index flirted with triple digits even before the first raindrops arrived. The National Weather Service has issued a Severe Thunderstorm Watch until 7 p.m. for Cook, DuPage, Kane, Lake, Will and several surrounding counties, warning of wind gusts up to 60 mph, quarter-size hail and torrential downpours capable of triggering flash flooding. Multiple warnings have already been posted for portions of Cook, DuPage, DeKalb and Lake counties as storms race southeast out of Wisconsin. In addition, a rare Dust Storm Advisory is in effect for stretches of I-39, I-55, I-88 and I-355, where 50 mph outflow winds may suddenly drop visibility below one mile. Drivers are urged to pull over rather than plow ahead into brown-out conditions. The volatile atmosphere is being super-charged by an extended heat wave. Chicago’s thermometer has topped 90 °F on five of the past six days, and humidity is pushing Saturday’s “feels-like” values to 100–103 °F across the city and suburbs. To help residents stay cool, the Chicago Park District has opted to keep 22 beaches and 19 neighborhood pools open through Labor Day while adding cooling areas at major weekend events such as Market Days and the Bud Billiken Parade. Storm timeline • 3–5 p.m.: First line of severe cells crosses the Illinois–Wisconsin state line. • 5–7 p.m.: Core of the metro, including downtown Chicago, faces strongest wind and hail threat. • After 7 p.m.: Storms shift southeast, but scattered downpours may redevelop overnight. • Early Sunday: Additional heavy rain possible before a gradual lull by midday. Safety checklist • Seek sturdy shelter when thunder roars—lightning can strike 10 miles from a storm. • Never drive through flooded roadways; six inches of moving water can stall a car. • If caught in blowing dust, pull completely off the roadway, turn off lights and keep foot off the brake. • Heat index above 100 °F means drink water every 20 minutes and take frequent shade breaks. Looking ahead, forecasters expect highs to settle into the upper 80s Sunday with lingering humidity, then rebound to the low 90s Tuesday and Wednesday before a stronger cold front brings a more sustainable cooldown late next week. Until then, Chicago weather watchers will have to juggle umbrellas and ice water in equal measure.