Severe Thunderstorm Warning Issued: Timeline, Impact Zones & Urgent Safety Tips

Residents across the Midwest are bracing for another round of volatile summer weather as the National Weather Service (NWS) issues multiple severe thunderstorm warnings and watches stretching from northern Illinois into northwest Indiana and southern Wisconsin. The most urgent alerts cover the Chicago metro area this afternoon, where a Severe Thunderstorm Watch remains in effect for Cook, DuPage, Lake, Kane, Will and several surrounding counties until 8 p.m. CDT. Radar has already triggered separate Severe Thunderstorm Warnings for portions of DuPage County (until 4 p.m.) and Cook County (until 4:15 p.m.), with storms racing east at 30 mph and packing wind gusts over 60 mph, quarter-size hail and blinding downpours that could flood underpasses in minutes. Travel disruptions are mounting: ground stops have been ordered at both O’Hare and Midway, where nearly 100 flights are already canceled and average delays hover around half an hour. Commuters are urged to monitor airline apps and leave extra time for evening trains and buses as lightning may force brief service suspensions. Why today’s storms are dangerous • Wind threat: Any gust stronger than 58 mph meets the NWS definition of a severe thunderstorm and can topple trees or peel shingles from roofs. Straight-line winds of that magnitude have historically produced damage comparable to weak tornadoes. • Large hail: Hailstones at least one inch in diameter (about the size of a U.S. quarter) are also a key warning trigger; they can dent vehicles, shred siding and injure pets or livestock left outdoors. • Isolated tornado potential: Embedded rotation along the squall line could briefly spin up tornadoes, especially near the Illinois–Wisconsin state line where a separate Tornado Watch remains posted. Timing: Forecasters expect the most intense activity between 3 p.m. and 8 p.m. CDT, coinciding with peak commute and outdoor events. A second, weaker wave of storms may redevelop pre-dawn Thursday as a cold front stalls over the region. Safety checklist before storms hit 1. Enable wireless emergency alerts and download a reliable weather app with real-time lightning tracking. 2. Secure patio furniture, umbrellas and trash bins; projectiles become airborne at 50-plus mph. 3. Park vehicles in a garage or under sturdy cover to minimize hail damage. 4. Identify or create a safe room on the lowest floor, away from windows—preferably an interior bathroom or basement. 5. Keep flashlights, power banks and a NOAA Weather Radio close in case of outages. Post-storm hazards Downed power lines may remain energized; stay at least 30 feet away and report them to utilities. Urban flooding can linger even after the rain stops, so never drive across water-covered roads. Heat index values near 100 °F earlier in the day mean that power outages could quickly create dangerous indoor temperatures; check on elderly neighbors who rely on air-conditioning. Outlook While tonight’s front will shave a few degrees off daytime highs, forecasters warn the atmosphere stays primed for scattered thunderstorms Thursday and again over the weekend. Homeowners should photograph any hail or wind damage promptly for insurance claims and keep tarps on hand for temporary roof repairs. Stay plugged in to local NWS offices, city emergency alerts and trusted broadcast meteorologists as watches evolve into warnings. Preparedness now can prevent injuries and costly damage when the next severe thunderstorm warning lights up your phone.