UNITED STATES — A significant two-day severe thunderstorm threat is developing across the Great Lakes region starting Monday night, March 30 and continuing through Tuesday, March 31, 2026. Storms are expected to fire around sunset Monday and last through the overnight hours, with a second and more widespread round spreading eastward across the Great Lakes and Ohio Valley on Tuesday. This is also the beginning of a broader pattern change that forecasters warn will bring severe weather risks nearly every day across the Plains and Eastern United States through Easter weekend.
Both outlooks were issued March 29, 2026 at 4:30 AM ET.
How the Two-Day Event Unfolds
This is not two separate storm systems — it is one continuous weather event moving eastward across the Great Lakes corridor over 36 hours.
Monday night, March 30 — Thunderstorms develop around sunset across Wisconsin, northern Illinois, and Iowa. The storm window opens as daytime heating gives way to evening instability, allowing the first round of severe weather to fire along a corridor from La Crosse and Wausau through Green Bay, Milwaukee, Rockford, Chicago, and Davenport. Storms will last into the overnight hours before gradually pushing eastward…