The National Weather Service has issued a Flash Flood Warning for Southern Effingham County and Southern Fayette County until 2:15am on Wednesday.
At 8:13am, thunderstorms producing heavy rain was located across the warned area.
Up to two inches has already fallen.
Additional rainfall could potentially reach 1 to 2 inches.
Locations impacted include Altamont, Watson, Edgewood, Mason, Elliotstown, Altamont Reservoir, Heartville, Vandalia, St. Elmo, Brownstown, Farina, Shobonier, Avena, La Clede, Pittsburg, St. Peter, Loogootee, St. James, St. Paul, and Hagerstown.
Motorists are reminded to turn around when encountering flooded roads.
Be especially cautious at night, when it is harder to recognize the threat of flooding.