MIAMI - Hurricane Arthur is strengthening in the Atlantic, threatening to become a Category 2 storm when it passes over or near the North Carolina coast on Independence Day.
Its maximum sustained winds late Thursday morning were 90 mph (150 kph). Hurricane warnings on North Carolina's coast stretch from Surf City to the Virginia border.
A hurricane watch is in effect for other parts of the state. A tropical storm warning covers parts of South Carolina and Virginia.
The National Hurricane Center in Miami says Arthur is centered about 260 miles (415 kilometers) southwest of Cape Hatteras, North Carolina, and about 110 miles (175 kilometers) south-southwest of Cape Fear. It's moving north at 14 mph (22 kph).
Residents and visitors on parts of North Carolina's popular but flood-prone Outer Banks are under evacuation orders.
Arthur-related worries have prompted some East Coast cities to reschedule July Fourth festivities and warn of dangerous rip tides.