A cold front moving through Central Illinois is expected to produce up to a quarter inch of rain and gusts as high as 34 mph, according to the National Weather Service.
Isolated storms are forecast Saturday afternoon for Macon, Moultrie, Piatt, Sangamon, Shelby, De Witt and 13 other counties.
Radar shows the storm system stretching across the entire state and into Wisconsin and Missouri.
Mostly cloudy skies are expected during the early evening in the Decatur area, then gradual clearing, with a low of about 53 degrees, the weather service said.
Sunny skies and a high near 79 degrees are forecast for Sunday.