Experts warn of storm surges in parts of Mexico and Cuba
Louisiana Governor Bobby Jindal has declared a state of emergency as the US Gulf Coast are braced for the arrival of Hurricane Ida.
Forecasters says the category 2 storm is entering the Gulf of Mexico with winds of up to 100mph (160 kph).
Ida is expected to gather speed as it moves north over open water towards the US coast.
However, the National Hurricane Center said it is expected to weaken before reaching the Gulf Coast by Tuesday.
At 2100 GMT on Sunday, the centre said Ida was about 95 miles (155km) west-north-west of Cuba, moving at about 10mph (16km/h) per hour.
The storm has already lashed parts of Central America and a tropical storm warning is in place for the western tip of Cuba.
Forecasters warned that Ida could bring up to 5in (12cm) of rain to the Mexican state of Yucatan and western Cuba, as well as storm surges and "large and destructive waves".
A separate low-pressure system coupled with the tail end of Ida also caused torrential rain in El Salvador which left more than 90 people dead from floods and landslides.
"Ida is expected to begin losing tropical characteristics on Tuesday as it nears the Gulf Coast but it could reach the coast as a tropical cyclone," the hurricane centre said.
A hurricane watch is in effect from south-east Louisiana to the Florida panhandle, meaning hurricane conditions are possible in the next day and a half.
The state of emergency declaration is a precaution that frees up state resources. The National Guard and state agencies have been put on high alert.
New Orleans is not included in the watch area.
Last year Hurricane Gustav caused an estimated two million people to flee inland from the Louisiana coast.