Nate, the fourth major storm to hit the US in less than two months, killed at least 30 people in Central America before entering the warm waters of the Gulf of Mexico and bearing down on southern states. It has also shut down most oil and gas production in the Gulf.

Nate comes on the heels of three other major storms, Harvey, Irma and Maria, which devastated Texas, Florida and Puerto Rico. But as a category 1, the weakest in the five-category ranking used by meteorologists, Nate appeared to lack the devastating punch of its predecessors.

The president, who was at his golf club in Virginia before attending a fundraiser in South Carolina on Saturday night, approved an emergency declaration for a large part of Louisiana and ordered federal assistance.

Trump has faced sustained criticism over his response to the aftermath of hurricanes Jose and Maria in Puerto Rico – sizeable storms which followed Harvey in Texas and Irma in Miami in a costly hurricane season.

He said on Twitter: “Our great team at Fema [Federal Emergency Management Administration] is prepared for Hurricane Nate. Everyone in LA, MS, AL and FL please listen to your local authorities and be safe.”

The National Hurricane Center (NHC) downgraded its warning for New Orleans to a tropical storm. But Nate was expected to regain some strength and make a second landfall along the coast of Mississippi to the east.

“The only thing you can do is prepare,” said Emmett Bryant from Gulfport, Mississippi. “Here there’s nothing really you can do when the storm comes unless you’re going to leave. And I don’t plan on leaving.”

The hurricane’s center was expected to pass over parts of Mississippi, Alabama, and Tennessee, eventually weakening to a tropical depression. Before then, storm surges of up to 11ft (3.4 meters) on the Mississippi-Alabama border were still possible, the NHC said.

In Hancock County, Mississippi, north-east of New Orleans, rain and wind were gaining intensity and many streets were washing over. The county evacuated people from low-lying areas and imposed a curfew.

Earlier in the day, states of emergency were declared in Louisiana, Mississippi and Alabama, as well as in more than two dozen Florida counties.

In a statement, the City of Biloxi, Mississippi, warned its 46,000 residents the highest storm surge would occur between 10pm and 3am and could reach 11-12ft.

In Alabama, governor Kay Ivey urged residents in areas facing heavy winds and storm surges to take precautions.

Some 5,000 people in southern Alabama were without power due to Nate, Alabama Power said.

Rainfall of up to 10in (25cm) was expected east of the Mississippi river from the central Gulf Coast into the Deep South, in the eastern Tennessee Valley, and southern Appalachians, the NHC said.

Rainfall in the Ohio Valley and into the central Appalachian mountains could reach a maximum of 7in (18cm).

New Orleans mayor Mitch Landrieu lifted a curfew in the city on Saturday evening that was originally scheduled to last until Sunday morning. He said in a statement on social media however, that there was still a serious threat of storm surge outside levee areas.

Plaquemines Parish south of New Orleans evacuated 240 residents who were not protected by its levee system as the storm approached. “While it appears we’re being spared ... our hearts go out to Mississippi,” said Amos Cormier, president of Plaquemines Parish, a low-lying area south of New Orleans.

Major shipping ports across the central US Gulf Coast were closed to inbound and outbound traffic on Saturday, as Nate intensified and storm surges of up 11ft were expected at the mouth of the Mississippi River.

The storm has curtailed 92% of daily oil production and 77% of daily natural gas output in the Gulf of Mexico, more than three times the amount affected by Harvey.

Workers had been evacuated from 301 platforms and 13 rigs as of Saturday, said the US Bureau of Safety and Environmental Enforcement.

Before heading north into the Gulf, Nate brushed Mexico’s Yucatan peninsula, home to beach resorts such as Cancun and Playa del Carmen, the NHC said.

The storm doused Central America with heavy rains on Thursday, killing at least 16 people in Nicaragua, 10 in Costa Rica, two in Honduras and two in El Salvador.

Thousands were forced to evacuate their homes and Costa Rica’s government declared a state of emergency.

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