Overview
- A compact mesoscale convective system that formed over eastern South Dakota produced measured gusts up to 90 mph and is moving east under active Storm Prediction Center watches.
- The SPC has issued multiple severe thunderstorm watches including Watch 443 for northwest Iowa, southwest Minnesota and southeast South Dakota to cover the fast‑moving line and pockets of supercells.
- Forecasters warned on Thursday that northern Iowa into southwestern Wisconsin faces a growing risk of very large hail and damaging winds while the Weather Prediction Center highlighted 2–4 inch rainfall totals and likely flash flooding where storms train.
- Local National Weather Service offices issued severe‑storm warnings in southeast Wisconsin for 60 mph gusts and urged people at outdoor events to seek shelter immediately.
- The pattern of extreme instability and strong midlevel flow that has produced long‑lived supercells and rapid upscale into destructive bowing systems is expected to keep downstream watch needs and damaging‑wind threats possible into the overnight hours.