New Orleans and Mobile are bracing for heavy rainfall on Monday, but the real flood threat ramps up Tuesday. Widespread, heavy rain is expected to soak the Deep South, potentially leading to significant flooding.

The FOX Forecast Center is monitoring a multiday flash flood threat across the Deep South as drenching rain pushes through the region starting Sunday.

A large area of high pressure that brought an arctic chill to much of the South and East this week is moving off Florida and now, ironically, in its wake is set to push a southerly fetch of tropical moisture from the Gulf of Mexico along into the Gulf Coast.

A multiday flash flood threat has millions of people in the South, including those in Atlanta and New Orleans, on alert as rounds of heavy rain push through the region this week.