Coastal residents from Florida to Louisiana are bracing for a deluge as Tropical Storm Gordon strengthens on a path to hit the central US Gulf Coast as a hurricane.

Boaters evacuated to safe harbours, motorists left barrier islands and homeowners looked over yards that could soon be submerged in seawater.

A number of schools called off classes, and red no-swimming flags flew along the shore as waves kicked up from the approaching storm.

Pensacola Water Safety Captain Jake Wilson said the strong wind is bringing a lateral current “where it’s just going to push you down the beach”.

A hurricane warning was put into effect for the mouth of the Pearl River in Mississippi to the Alabama-Florida border.

The National Hurricane Centre predicted a “life-threatening” storm surge along parts of the central Gulf Coast, and as much as 8in of rain could fall in some parts of the Gulf states through to late Thursday as the weather front moves over the lower Mississippi Valley.

The storm was east-south-east of the mouth of the Mississippi River, with top sustained winds of 65mph, forecasters said. It was moving relatively quickly, at about 15mph.

A storm surge warning was issued for the area stretching from Shell Beach, Louisiana, to Dauphin Island, Alabama.

The warning means there is danger of life-threatening inundation, with rising waters of 3ft to 5ft.

Louisiana governor John Bel Edwards declared a state of emergency on Monday and said 200 National Guard troops will be deployed to the south-east of the state.

Mississippi governor Phil Bryant also declared a state of emergency and said state resources are being mobilised, while Alabama governor Kay Ivey followed suit.

Gordon formed into a tropical storm near the Florida Keys early on Monday, lashing the southern part of the state with heavy rains and high winds before moving into the Gulf of Mexico.

The storm’s predicted track had shifted slightly east as of Monday evening, meaning Louisiana is just outside the area under the hurricane warning, but the south-eastern part of the state remains under a tropical storm warning and residents need to be prepared for the storm to shift west, Mr Edwards said.

Tropical Storm Gordon approaches the US
Tropical Storm Gordon approaches the US (NOAA/AP)

New Orleans mayor LaToya Cantrell said the city has “the pumps and the power” needed to protect residents, but authorities issued a voluntary evacuation order for areas outside the city’s levee protection system, including the Venetian Isles, Lake Saint Catherine and Irish Bayou areas.