NEW ORLEANS, LA. - A tropical weather system was expected Wednesday to develop into a storm that could push the already swollen Mississippi River precariously close to the tops of levees that protect New Orleans.

The low pressure area was over water, south of the Florida Panhandle early Wednesday and was expected to strengthen into a storm as it moved west through the Gulf's warm waters.

Forecasters say parts of Louisiana could see up to 12 inches (30 centimeters) of rain by Monday, with heavier amounts possible in some spots.

Mississippi and Texas were also at risk of torrential rains.

The National Weather Service said New Orleans is protected to a river level of 20 feet (6.1 meters), but it was forecast to rise above flood stage to 19 feet (5.8 meters) by Friday.

Though much of the heaviest rain isn't expected until the weekend, the broad area of disturbed weather in the Gulf was already producing strong thunderstorms over Louisiana on Wednesday. Those storms prompted tornado and flash flood warnings Wednesday morning in the New Orleans area. The weather service said up to 3 inches (7.6 centimeters) of rain had fallen in the area.