More widespread flash flooding and river flooding is likely from Texas to the Carolinas this week.
'Areas of significant flooding and flash flooding are expected today into tonight across portions of Louisiana, Mississippi, Alabama, Georgia, Tennessee, and the far western Carolinas,' the Weather Prediction Center posted Monday.
Parts of northern Mississippi, Alabama, and Georgia are under a high risk (level 4 of 4) for flash flooding, according to the Weather Prediction Center. The high risk area includes Atlanta and Birmingham, Alabama.
Flood watches have already been issued for nearly 18 million people through Tuesday. This includes cities like Atlanta and Birmingham, along with Jackson, Mississippi and Shreveport, Louisiana.
In Birmingham Monday, firefighters were out for at least five water rescues already, CNN affiliate WBMA reported.
'Rainfall totals of 3 to 5 inches, with locally over 6 inches are expected over the region over the next 24 hours,' CNN meteorologist Dave Hennen said.
This storm system comes on the heels of multiple rounds of storms that already saturated the ground.
The ground is like a sponge. Once it is soaked, it can't hold water anymore and that is when any additional rainfall becomes a concern.
Showers and thunderstorms will result in 3 to 5 inches of rainfall across portions of the Southeast, with locally higher amounts likely.
'Along with the heavy rain, there will be several rounds of severe weather this week, with large hail, damaging winds, and tornadoes,' Hennen said.
Monday's threat is a slight (level 2 of 5) risk that extends from far east Texas into Mississippi, with damaging winds the primary threat.
The National Weather Service in Jackson, Mississippi, issued a tornado warning Monday night after a twister was spotted on the ground close to nearby Phoenix.
Tuesday will see a few isolated storms in the Southeast. Wednesday, the threat for severe storms increases as another system moves through.
Much of the Southeast will see the threat for storms, with an enhanced risk (level 3 of 5) already issued from Louisiana into Alabama for Wednesday.
These storms midweek will bring more flooding rainfall as well as the possibilities of damaging winds and tornadoes.