A severe thunderstorm watch is in effect for several west and northwest Iowa counties until 2 a.m. Wednesday. These include Adubon, Buena Vista, Calhoun, Carroll, Cherokee, Clay, Crawford, Greene, Guthrie, Harrison, Ida, Lyon, Monona, O'Brien, Osceola, Plymouth, Pocahontas, Sac, Shelby, Sioux, Webster and Woodbury counties.

A strong storm system is expected to bring severe thunderstorms to Central Illinois on Wednesday, with heavy rain, strong wind gusts, and isolated tornadoes possible, before a cooler and more comfortable pattern emerges for the end of the week and weekend.