The governors of North and SC and Virginia declared states of emergency.
The South Carolina Emergency Management Division went to Operating Condition 3 (OPCON 3) Sunday morning, That means the agency's operations center in West Columbia, which is where all emergency efforts will be coordinated, is fully activated.
Tropical Storm Florence, the sixth named storm, is expected to become a hurricane Saturday night, the NHC said.
Florence is expected to be back at Cat 4 as it approaches the Atlantic Coast this Wednesday to Thursday.
Though weakened to a tropical storm, Florence was expected to regain hurricane strength as it neared Bermuda.
Forecasters said it is now around 1,500 miles east of the Windward Islands and is carrying winds of 65mph (100kph).
A third storm, Hurricane Helene, was spinning in the Atlantic off West Africa's Cabo Verde Islands with 75-mph (121-kph) winds on Sunday, but did not appear to pose an immediate threat to land.
Florence continued its west-northwest crawl toward the southeastern US coast, packing maximum sustained winds of 90 miles per hour.
Serena, Stephens try to reach semifinals at US Open
I feel like she has a big chance because the players which stayed [in the tournament], I feel like she can beat all of them". You can't control the weather, can't control what the tournament is going to do. "So obviously I know her game really well".
Officials in the Carolinas warned residents to prepare and to brace for impact. A tropical storm becomes a hurricane when maximum sustained winds reach at least 74 miles per hour.
"However, given the uncertainty in track and intensity forecasts at those time ranges", the National Hurricane Center tweeted, "it's too soon to determine the exact timing, location, and magnitude of those impacts".
The two weather systems churning in the Atlantic Ocean continue to gain strength, with Helene now a Category 1 hurricane and Isaac projected to become one by tonight. Drawing energy from the warm water, it could be a fearsome Category 4 with winds of 130 miles per hour or more by Tuesday, the National Hurricane Center said.
Unsafe swells generated by Florence affected Bermuda and have begun to reach parts of the Eastern Seaboard.
Jack Ma, Alibaba co-founder and China’s richest man, announces retirement
Mr Ma began his professional life teaching English at a university in the Chinese city of Hangzhou, in eastern Zhejiang province. Ma will remain on the company's board of directors and continue to mentor Alibaba employees, according to the New York Times .
There are no coastal watches or warnings in effect, but officials say it is expected to become a hurricane by Monday.
Swells generated by Florence could cause unsafe rip currents and coastal flooding today in some areas including coastal DE and New Jersey, according to the National Weather Service.
"This storm is too powerful and its path is too uncertain to take any chances", South Carolina Governor Henry McMaster said in issuing his state's emergency declaration.
The hurricane's maximum sustained winds have increase to near 140 km/h with higher gusts.
Rapper Post Malone’s Rolls Royce crashes in West Hollywood
Post Malone had been in the NY area on Monday for the MTV Video Music Awards, where he won the song of the year prize. The FAA later told Fox News the plane has been diverted to Stewart Airport, located north of New York City.