“All areas of northern Illinois and northwest Indiana are at risk for torrential rain rates, which can lead to flash flooding today,” the NWS warned.
The heavy rain will last throughout the morning, Roman said, though there could be an afternoon window where the rain tapers before stronger storms move in. The NWS described that round as “potentially more dangerous,” with all weather hazards possible and the entire Chicago area under threat of severe weather.
Good morning, there remains a threat for severe weather today w/1 or 2 rounds of storms possible. Conditions will be favorable for fast-moving severe storms, especially during the afternoon and near/south of a warm front. Here are additional details on the forecast. pic.twitter.com/pHkmIspe2t
— NWS Chicago (@NWSChicago) June 17, 2026
Wednesday afternoon
The second round of storms starts about 2 p.m., Roman said, “clusters of supercells” possible…