Hurricane Dorian is expected to bring “life-threatening storm surges” up the US east coast after causing destruction and at least 20 deaths in the Bahamas.
The category two storm is currently lashing the coast of the Carolinas as it moves slowly north. Tens of thousands of people are without power.
Residents from Georgia to Virginia are being told to listen to official advice.
Weather officials said Dorian would weaken slowly over the next few days.
It currently has maximum sustained winds of 110mph (175km/h), down from 115mph earlier in the day.
On 1 September it hit the Bahamas with winds of up to 185mph – equalling the highest ever recorded at landfall. It battered the Abaco Islands and Grand Bahama, in the north of the archipelago, for two days.
Bahamas PM Hubert Minnis called the storm “one of the greatest national crises in our country’s history”. He expected the number of fatalities to increase.
What’s the latest on the storm?
The US National Hurricane Center (NHC) said that at 11:00 local time (15:00 GMT) Dorian was 50 miles (80km) south-east of Charleston and moving north at about 8mph.
The NHC said Dorian “continues to lash the coast of the Carolinas. Hurricane conditions are likely over portions of the area later on Thursday”.
It is expected to turn north-east later on Thursday and speed up.