The National Weather Service says heavy rain can be expected through Monday and into Tuesday, as the quad-state region is already trying to recover from several inches of rain over the weekend..
Forecasts call for several more inches of rain across the region, as remnants of a tropical system make their way north and east from the Gulf of Mexico.
Some parts of the quad-state region could see eight inches of rain, with the precipitation falling at two to four inches per hour at times.
A Flash Flood Watch has been extended for the area - now in effect through Tuesday morning.
Emergency Management Agencies across southern Illinois, southeast Missouri, western Kentucky, and southwest Indiana are warning people to be ready for flash flooding - including roads under water and rivers and creeks flooding.
Rain and thunderstorms are likely through early Tuesday, with the chance of precipitation dropping off by mid-week.