The Center of Hurricane Florence was about 25 miles east of Wilmington, North Carolina at 4 a.m. (0800 GMT) on Friday, the U.S. National Hurricane Center (NHC) said.
The category 1 hurricane, due to make landfall later on Friday, was packing peak winds of 90 mph (150 km/h).
The storm is expected to weaken significantly over the weekend and into early next week as it moves farther inland, the NHC said.