This article is more than 2 years old

This article is more than 2 years old

Forecasters said Tropical storm Florence turned into a hurricane and was swirling toward the US east coast for what could be a direct hit on Friday. At category one status on Sunday, it was predicted to reach category four status, with winds of 130mph or more, while moving over the Atlantic.

On Sunday morning the storm’s sustained winds reached 75mph, just over the threshold for a hurricane, as it was about 750 miles south-east of Bermuda. It was moving west at 6mph.

The National Hurricane Center (NHC) said it was too early to predict the hurricane’s path, but a huge coastal area from northern Florida to North Carolina should prepare for a major hit.

Florence was forecast to become a “major hurricane” on Monday, travel between Bermuda and the Bahamas on Tuesday and Wednesday before approaching the south-eastern US coast on Thursday, the Miami-based NHC said.

Pretend, assume, presume that a major hurricane is going to hit right smack dab in the middle of South Carolina Governor Henry McMaster

It later added: “All indications are that Florence will be an extremely dangerous category four hurricane while it moves over the western Atlantic toward the south-eastern United States.”

A category four storm has the potential to cause catastrophic damage. Officials in the Carolinas warned residents to prepare and to brace for impact. Governors in South Carolina and Virginia declared states of emergency.

On Friday, North Carolina governor Roy Cooper urged residents to use the weekend to prepare for the possibility of a natural disaster.

“We are entering the peak of hurricane season and we know well the unpredictability and power of these storms,” Cooper said.

South Carolina governor Henry McMaster told a Sunday news conference that people should “pretend, assume, presume that a major hurricane is going to hit right smack dab in the middle of South Carolina and is going to go way inshore”.

Residents should count on “a lot of wind and a lot of rain” , he said.

In Charleston, city officials were offering sandbags for residents to fill. Myrtle Beach mayor Brenda Bethune urged residents to secure their homes, but said it was too early to know if evacuations will be ordered.

The US navy was making preparations for ships in the Hampton Roads area to leave port. The US Fleet Forces Command said in a release on Saturday ships would get ready in anticipation of getting under way on Monday to avoid storm damage.

Adm Christopher Grady said the decision was based on Florence’s current track, which indicates the area could see strong sustained winds and storm surges. The news release noted that plans could change.

Swells generated by Florence were affecting Bermuda and starting to reach parts of the eastern seaboard, the National Weather Service said.

Cruise lines were redirecting their ships to avoid the path of the storm. Carnival Cruise Line said on Sunday it had changed the schedule of its ships to accommodate tropical weather threats. Carnival Pride was scheduled to leave Baltimore and head to Bermuda.The ship will now head to the Bahamas.

The company also said Carnival Horizon had cancelled plans to visit San Juan in Puerto Rico on Sunday. It is expected to arrive in New York on 13 September.

A new tropical storm formed in the eastern Atlantic, meanwhile. The NHC said on Sunday morning Tropical storm Isaac was centered about 1,540 miles east of the Windward Islands. Officials said it was expected to become a hurricane by Monday.