Severe thunderstorm outbreak forecast across Midwest and Great Lakes

Day 1 Convective Outlook valid from UTC on June 11 to UTC on June 12, 2026. Credit: NWS/SPC The Storm Prediction Center (SPC) issued a Moderate Risk for severe thunderstorms across northern Illinois, far eastern Iowa, and far southern Wisconsin on June 11, as an outbreak-level severe weather setup develops across parts of the Midwest and Great Lakes. Widespread damaging winds, large hail, and several tornadoes, some strong to intense, are forecast this afternoon and evening. SPC’s updated Public Severe Weather Outlook, issued at UTC, places far eastern Iowa, northern and central Illinois, southern Wisconsin, northern Indiana, northern Missouri, and Lower Michigan as the main exposed areas. The agency warned of widespread damaging winds, some hurricane force, several tornadoes with a couple intense, and isolated large hail up to baseball size. Widespread severe thunderstorms are expected from far eastern Iowa, northern Missouri, northern and central Illinois, and southern Wisconsin into Lower Michigan and northern Indiana, with damaging winds over 120 km/h (75+ mph), large hail, and several tornadoes, some strong to intense. According to SPC, an ongoing bowing cluster across southeastern Iowa, northwestern Illinois, southwestern Wisconsin, and nearby areas may continue to pose at least some severe wind threat and a threat for embedded tornadoes while moving east-northeast this afternoon. Ahead of the cluster, air mass recovery is underway across central and northern Illinois, northern Indiana, and parts of southern Lower Michigan, where surface heating is occurring. Day 1 Convective Outlook valid from UTC on June 11 to UTC on June 12, 2026. Credit: NWS/SPC Day 1 Tornado Outlook valid from UTC on June 11 to UTC on June 12, 2026. Credit: NWS/SPC Day 1 Wind Outlook valid from UTC on June 11 to UTC on June 12, 2026. Credit: NWS/SPC Day 1 Hail Outlook valid from UTC on June 11 to UTC on June 12, 2026. Credit: NWS/SPC The later severe weather risk depends on redevelopment along the southern and western flank of the ongoing convection from northern Illinois into northeast Missouri. If semi-discrete supercells are maintained, several tornadoes and multiple strong to intense tornadoes rated EF2/EF3+ are possible, with isolated large to very large hail from sustained supercells. Additionally, numerous to potentially widespread severe and damaging winds can be expected from northern and central Illinois into southern Lower Michigan and northern Indiana, with some gusts again forecast to exceed 120 km/h (75 mph). Thunderstorms are also forecast along the trailing cold front from eastern Kansas and southern Missouri into parts of the Southern Plains this afternoon and evening.