New Orleans and Mobile, Alabama, 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 said some areas could see over 3 inches of rain through Wednesday, providing drought relief for many. Additionally, a low threat of severe storms is possible on Tuesday and Wednesday.HOW TO WATCH FOX WEATHERThe FOX Forecast Center said rain will continue Monday morning as a weak area of low pressure starts to develop. A warm front will position itself along the northern Gulf Coast, confining the worst rain to places like Louisiana and southern Alabama. Places like New Orleans and Mobile are on the bullseye to start the workweek. DOWNLOAD THE FREE FOX WEATHER APPA Flood Watch remains in effect for portions of southeast Louisiana and southern Mississippi through Tuesday morning.As this low organizes and rapidly lifts north, a powerful cold front will form, pulling an abundant amount of moisture from the Gulf, the FOX Forecast Center said. Late Tuesday will be the biggest period for flash flooding as the threat grows to cover cities from Atlanta to Mobile and eventually the entire East Coast.When all is said and done, rain totals across Texas, Louisiana, Alabama, and Georgia will add up to a widespread 2-3 inches, with locally higher amounts of more than 5 inches possible. This will be beneficial for far southeastern Texas and central Alabama, which are still in severe to extreme drought.Additionally, outside the chance for flash flooding, the FOX Forecast Center is monitoring for a couple of days of severe storms for the Deep South coming late Tuesday. Damaging wind gusts and a tornado or two as the cold front rapidly moves through.