After barreling portions of Central America, Tropical Storm Nate is expected to reach the US Gulf Coast over the weekend as a hurricane.
The storm has killed at least 22 people in Nicaragua, Costa Rica and Honduras, where the storm has caused widespread flash flooding and mudslides, officials said.
Nate is forecast to gain force as it approaches the Yucatan Peninsula late Friday and turn into a Category 1 hurricane when it makes landfall in the US Gulf Coast on Sunday, the National Hurricane Center said.
The center said the storm has sustained winds of 45 mph and is moving northwest at 12 mph.
Parts of the Louisiana, Mississippi and Alabama coastlines are under hurricane and tropical storm watches. The storm could drop 3 to 6 inches of rain and up to 12 inches in some areas, the National Weather Service said.
New Orleans vulnerable, Florida prepares
New Orleans Mayor Mitch Landrieu declared a state of emergency for the city on Thursday and advised residents to stay put over the weekend.
"There is no need to panic. Be ready and prepare. Get a plan. Prepare to protect your personal property," Landrieu tweeted.
The city's unique drainage system has recently experienced critical deficiencies. Several drainage pumps failed during heavy rainstorms in August, leading to the flooding of several hundred properties.
Louisiana Gov. John Bel Edwards said he authorized 1,300 National Guard troops to mobilize ahead of the storm and some will be in New Orleans to help the city monitor the pumps.
Though Florida is not under any hurricane or tropical storm warnings, the state's western Panhandle could be impacted by Nate's wind, storm surge and heavy rainfall, the hurricane center said.
With some parts of Florida still reeling from Hurricane Irma, Gov. Rick Scott declared a state of emergency for 29 counties and encouraged residents to get prepared in case the track of Nate changes.
"Just think about your family: Get your three days of water, three days of food; if you're taking medicine, make sure you have your medicine," he said during news conference on Thursday.
At least 22 people were killed and several people remain missing as the storm hit Central America, officials said.
Hundreds were rescued from flood waters and many have lost power and running water in Nicaragua, Honduras and Costa Rica, officials said.
The main threat for Central America has been heavy rainfall, which has caused life-threatening flash flooding and mud slides.
Costa Rica President Luis Guillermo Solis declared a national state of emergency to assist those affected by the storm.
Forecasters said portions of Nicaragua, Honduras, Costa Rica, Panama, and Belize will continue seeing rainfall through Friday night.