SPC forecasts supercells and damaging wind clusters across Iowa late May 15
The Storm Prediction Center (SPC) placed Iowa under an Enhanced Risk for severe thunderstorms late May 15, 2026, with severe/damaging winds and large to very large hail forecast late this afternoon and evening. Initial supercells may produce hail of 5 cm (2 inches) or larger before storms organize into clusters capable of localized wind gusts above 120 km/h (75 mph).










