BUXTON, N.C. (AP) — Hurricane Earl was barreling toward the Eastern Seaboard on Thursday with winds swirling at around 145 mph and forecasters were trying to pinpoint exactly how close the strongest winds and heaviest surge would get to North Carolina's fragile chain of barrier islands.

They also were trying to figure out whether the storm would stay off the Northeast coast or bring hurricane-force winds to Long Island, the Boston metropolitan area and Cape Cod.

Tourists were largely gone from North Carolina's Outer Banks, but those resolute residents who stayed behind said they were prepared to face down the powerful hurricane.

"There is still concern that this track, the core of the storm, could shift a little farther to the west and have a very significant impact on the immediate coastline. Our present track keeps it off shore, but you never know," National Hurricane Center spokesman Dennis Feltgen said.

The National Hurricane Center in Miami issued a tropical storm warning early Thursday for the coast of Long Island in New York and a hurricane watch was issued for areas of Massachusetts. A hurricane warning was already in effect for the coast of North Carolina.

Earl's first encounter with the U.S. mainland should come around midnight Thursday, as the storm is forecast to pass just off Cape Hatteras, bringing wind gusts of up to 100 mph and several feet of storm surge both from the Atlantic and the sounds to the west of the islands.

Evacuations continued early Thursday on the North Carolina coast, with residents and visitors leaving a barrier island in Carteret County. Emergency Services Director Jo Ann Smith said she wasn't sure how many people were affected by the order to leave the Bogue Banks areas. Unlike some of the barrier islands on the Outer Banks who had to take a ferry, Smith said people could simply leave in their cars.

The Outer Banks had only light winds and high clouds early Thursday as the eye of Earl was hundreds of miles south of Cape Hatteras. Those conditions were expected to deteriorate throughout the day, said National Hurricane Center forecaster Todd Kimberline.

While thousands of tourists heeded calls to evacuate Hatteras Island, locals familiar with hurricanes vowed to ride out Earl, preparing to spend days stranded from the mainland. Dare County officials said the daring should be ready to fend for themselves for up to three days.

Residents like Nancy Scarborough, who manages the Hatteras Cabanas, said Outer Banks residents have a tight-knit community that takes care of its own.

"I worry about not being able to get back here,'" she said. "I'd rather be stuck on this side than that side."

Along with the 30,000 residents and visitors asked to leave Hatteras Island, 5,000 more tourists were ordered to leave Ocracoke Island, which is only accessible by ferry and airplane.

Many people — boaters, beachgoers and residents alike — were adopting a wait-and-see approach, making simple preparations like stocking up on food or attaching hurricane shutters to their houses. But with the likelihood that the storm's ultimate path will become clear on Thursday, officials expect planning to shift into high gear.

"Post-Katrina, people are really sensitive to storm preparedness," said Atlantic Beach, N.C., Mayor Trace Cooper. "I don't think we're going to see too many people sticking around and saying they're going to have hurricane parties. You see enough pictures of people waiting on their roofs to be rescued and you decide to take precautions."

The North Carolina National Guard is deploying 80 troops to help and President Barack Obama declared an emergency in the state. The declaration authorizes the Department of Homeland Security and Federal Emergency Management Agency (FEMA) to coordinate all disaster relief efforts.

As Earl whirled into a powerful Category 4 storm, the governors of North Carolina, Virginia and Maryland declared states of emergency, the USS Cole hustled to return to its port in Virginia and volunteers carried sea turtle nests to safety. The highest storm category is 5 that has winds of 155 mph and higher.

Farther up the East Coast, emergency officials urged people to have disaster plans and supplies ready and weighed whether to order evacuations as they watched the latest maps from the hurricane center — namely, the "cone of uncertainty" showing the broad path the storm could take.

If Earl moves farther east, Friday might just be modestly wet and blustery for millions in the Northeast. If the storm runs along the western edge of the forecast, dangerous storm surge, heavy rain and hurricane-force winds could slam the populous region.

In Massachusetts, some boaters had already pulled their crafts from the water in anticipation of rough seas, said Harwich Assistant Harbor Master Heinz Proft. The Labor Day weekend is about the time of year when people start pulling their boats anyway, so some are just accelerating the process.

"It's been a small percentage so far, but we are encouraging people to be proactive," he said.

In Virginia, Gov. Bob McDonnell activated the National Guard and sent 200 troops to the Hampton Roads area on Chesapeake Bay. The area was not expected to get the brunt of Earl, but many remember the surprise fury of Isabel, which killed 33 people and caused $1.6 billion in damage in September 2003.

Tugboat captain Randy Francis planned to ride out the storm on his 40-foot trawler named "Invictus" at a marina in Norfolk, Va. He said most people didn't appear to be taking the hurricane seriously.

"I was somewhat frustrated that they were somewhat nonchalant about it here," Francis said. "I'd just rather be safe than sorry."

Red Cross officials in New York prepared to open as many as 50 shelters on Long Island that could house up to 60,000 people in an emergency.

Emergency officials on Cape Cod braced for their first major storm since Hurricane Bob brought winds of up to 100 mph to coastal New England in August 1991.