Tropical Storm Barry, which is currently moving over the Gulf of Mexico, is likely to develop into a hurricane.
It is forecast to hit the U.S. city of New Orleans, which has already seen thunderstorms and flash floods.
A state of emergency is in effect and residents in some low-lying areas have been asked to evacuate.
Officials warn that the Mississippi river could come dangerously close to over topping banks protecting the city.
They say, It could rise as high as 20 feet above sea level.