Arthur strengthened to a Category 2 storm with winds of 100 mph last night before passing over the southern end of the Outer Banks.
The storm is moving northeast after turning slightly west late yesterday, which increases the threat to mainland communities of flooding, tornadoes and intense winds.
Duke Energy says as many as 22,000 customers across the Carolinas may be without power.
Arthur is expected to weaken as it travels northward, dumping rain along the East Coast.
That's changed the July 4th plans of many communities. Fireworks shows in New Jersey and Maine are postponed until later in the weekend.