(This post was last updated at 6:57 p.m. ET.)
Churning just off the coast of Florida, Tropical Storm Arthur is gaining strength.
In its latest advisory, the National Hurricane Center said the storm now has maximum sustained winds of 70 mph, just 4 mph shy of becoming the Atlantic season's first hurricane.
The NHC says the storm has begun to move north and is forecast to move northeast, hugging the coast and perhaps making landfall in North Carolina. A hurricane warning has been posted for much of the North Carolina coast and a tropical storm warning has been posted for the northern South Carolina coast.
Dare County emergency management ordered an evacuation of Hatteras Island, which is vulnerable to storms, beginning at 5 a.m. ET. Thursday.
"A State of Emergency has been issued for all of Dare County with the only restriction being the mandatory evacuation of Hatteras Island," county emergency management said in a statement. "Visitors should evacuate with all personal belongings and follow instructions offered by their property management company."
The NHC forecasters say most of the strong winds, rain and coastal flooding should arrive in the area through the day Thursday and into Friday.
Here's a map of the forecast track:
The Washington Post's Capital Weather Gang says there is good confidence in this forecast.
"The northward motion will accelerate today, followed by a gradual turn to the northeast tomorrow," the report. "It is still expected to pass east of South Carolina tomorrow as a minimal hurricane, then graze the Outer Banks of North Carolina as a hurricane Thursday night into Friday morning. Then it heads offshore by a safer distance, passing east of the mid-Atlantic region during the day on Friday and east of New England on Friday evening/night, perhaps still as a hurricane."
NBC News reports that parts of North Carolina have begun preparing for the storm. NBC News adds:
"'Our major goal is to ensure that no lives are lost during this upcoming storm,' North Carolina Gov. Pat McCrory said at a news conference Wednesday afternoon.
"With dangers of rough surf and flooding, he cautioned people to heed the warnings from officials: 'Don't put your stupid hat on.'
"The tiny destination of Ocracoke Island in North Carolina began ordering voluntary evacuations Wednesday, as neighboring communities decide whether to make similar preparations. Earlier, McCrory declared a state of emergency for 25 coastal and adjoining inland counties ahead of Arthur's arrival."