A flood watch has been issued by the National Weather Service from 7 p.m. today until Thursday afternoon for much of the area.
Local counties listed in the watch include Wayne, Carter, Ripley, Stoddard and Butler.
Widespread 3 to 4 inches of rain is expected across the area over the next 24 hours, the Weather Service said.
As of 2:30 p.m. Wednesday, light rain had already begun arriving in Southeast Missouri as a storm system approached from the south.
Isolated thunderstorms are possible, but widespread severe weather is not expected.
Drivers are encouraged to turn around when encountering roads covered with water and find an alternate route.