RODANTHE, N.C. (CBS) -- Hurricane Arthur gained strength in the Atlantic on Thursday and threatened to strike near the North Carolina coast on Independence Day, prompting thousands of vacationers and residents to leave parts of the state's popular but flood-prone Outer Banks.
On Thursday afternoon, Arthur was about 225 miles southwest of Cape Hatteras and moving north around 13 mph with maximum sustained winds of 90 mph.
Nichole Specht, 27, and Ryan Witman, 28, had pre-loaded their Honda CRV and left Hatteras Island at 3:30 a.m. Thursday, beating the expected traffic jam. The island was under an evacuation order, with no traffic allowed in. Officials asked an estimated 35,000 residents and travelers to leave through North Carolina Route 12, the only road on and off Hatteras.
Specht and Witman found the road wide open for their return home to Lancaster, Pennsylvania. Specht said her parents left their rental later, at 5 a.m., and also found clear sailing.
"We were just saying we were really, really lucky this year that the weather was so great, and then this," Specht said as she ended a two-week vacation that included scouting sites for the couple's wedding next year.
Hurricane Arthur's widest effects? Hazardous rip currents
According to CBS affiliate WRAL, New Hanover County and the City of Wilmington have declared a state of emergency effective 10 a.m. Thursday. The North Carolina ferry system is shutting down the Ocracoke-Hatteras route at 5p.m. Thursday.
Forecasters expect Arthur speed up to a Category 2 storm and pass over or near the Outer Banks - a 200-mile string of narrow barrier islands with about 57,000 permanent residents - early Friday, bringing rain, heavy winds, storm surge and dangerous rip tides.
"We don't know for sure if the exact center of Arthur is going to pass over land or not. The chances have been increasing for that to occur with the last couple of forecasts. But even if the exact center doesn't go over you, you will experience impacts tonight. The weather is going downhill in North Carolina, even as we speak," said Rick Knabb, the director of the U.S. National Hurricane Center in Miami.
Before the storm hit, tourism officials had expected 250,000 people to travel to the Outer Banks for the holiday weekend. Gov. Pat McCrory warned people: "Don't put your stupid hat on," urging them to put safety before picnics, barbecues and pre-paid beach cottage vacations.
But some visitors stayed put, hopeful the fast-moving storm would follow predictions to pass through Friday and salvage the rest of the weekend. About 20 miles north of the only bridge off Hatteras, Sean Fitzgerald and his 5-year-old son, Cade, enjoyed a sunny morning lounging in beach chairs in the town of Kill Devil Hills.
The sand was dotted with tourists. A handful of surfers took to the water. Like all areas north of Oregon Inlet, Kill Devils Hills wasn't under an evacuation. Fitzgerald said he saw no need to disrupt his family's vacation.
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"I plan to sit on the beach as long as the sun is here," then head out for a seafood dinner, said Fitzgerald, 44, of Fairfax, Virginia.
Those who don't evacuate should prepare for possibly getting stuck for several days without food, water or power, National Hurricane Center forecaster Stacy Stewart said Thursday.
"We want the public to take this system very seriously, go ahead and start their preparations because time is beginning to run out," he said.
Arthur, the first named storm of the Atlantic season, prompted a hurricane warning for much of the North Carolina coast. Tropical storm warnings were in effect for coastal areas in South Carolina and Virginia. On the Outer Banks' Ocracoke Island, accessible only by ferry, a voluntary evacuation was underway. Officials said ferry service would end at 5 p.m.
Before sunset Wednesday on Route 12, a long line of cars, trailers and recreational vehicles formed a steady stream of traffic. The road has been sliced apart twice in recent years as storms cut temporary channels from the ocean to the sound. N.C. 12 is easily blocked by sand and water.
Officials called the evacuation for Hatteras Island residents and visitors mandatory, but some residents were likely to stay, as in past storms.
Mike Rabe of Virginia Beach, Virginia, planned to remain in his Outer Banks beach home the entire weekend. He and his wife, Jan, stowed lawn furniture and anything else that could be tossed about by winds, then planned to help a neighbor.
"I'm going to ride it out," Rabe, 53, said.
The holiday weekend was not expected to be a complete loss on the Outer Banks. Forecasters said the storm would move through quickly with the worst of the weather near Cape Hatteras about dawn Friday. Then it was expected to clear. The National Hurricane Center predicted Arthur would start to weaken Friday night.
Farther north, the annual Boston Pops Fourth of July concert and fireworks show was moved up a day because of potential heavy rain ahead of Hurricane Arthur. Organizers and public safety officials said the celebration was rescheduled for Thursday, which appeared to be the best of two potential bad weather days. Other cities along the East Coast warned of weather condition and potentially life-threatening rip currents.
If Arthur makes landfall in the U.S. on Friday, it would be the first hurricane to do so on July Fourth, according to National Hurricane Center research that goes back to the 1850s.