The National Weather Service (NWS) office in Des Moines has issued a severe thunderstorm warning until 4:15 p.m. Thursday for northeastern Dallas County, northwestern Polk County, southwestern Story County and southeastern Boone County.
At 3:34 p.m., a severe thunderstorm was identified over Big Creek Lake or 8 miles north of Johnston, moving southeast at 15 mph.
Quarter-size hail is expected to cause damage to vehicles.
Cities impaced by the warning include Ankeny, Johnston, Polk City, Saylorville, Madrid, Slater, Granger, Saylorville Lake, Big Creek Lake, Alleman, Sheldahl and Big Creek
State Park.
ThePerryNews.com will update this weather story as forecasts evolve.