Sioux City, Iowa – Tornado sirens could sound across parts of western Iowa Thursday evening as powerful thunderstorms push through the region under a Tornado Watch active until 10 p.m. CDT.
According to the National Weather Service’s Storm Prediction Center, Tornado Watch 501 includes Harrison, Monona, Plymouth, and Woodbury counties. Strong storms capable of producing tornadoes, damaging winds, and large hail are expected to intensify late this afternoon and evening, especially along the I-29 corridor.
In Sioux City, residents should prepare for sudden severe weather changes, with rotating supercells possible through 9 p.m. Emergency managers urge Iowans to have phones charged, weather radios on, and a safe shelter location identified. Travel is not advised during storms, especially in rural areas where visibility and road conditions may rapidly deteriorate.
Nearby towns such as Onawa, Harlan, and Le Mars should remain on high alert. The area is under enhanced risk due to high humidity, instability, and strong wind shear—conditions similar to June’s outbreak that caused wind damage and flooding in the region.
Storms are expected to weaken after sunset, but the threat remains active until all warnings expire.
