Kill Devil Hills, North Carolina (CNN) -- With the Outer Banks of North Carolina in its sights, large and powerful Hurricane Earl prepared Thursday to take a swipe at the Eastern Seaboard.

Hurricane warnings and watches stretched from North Carolina to Delaware, and covered parts of Massachusetts.

President Barack Obama signed a disaster declaration for North Carolina Wednesday evening, following an emergency declaration by Maryland's governor earlier in the day.

"The president's action authorizes the Department of Homeland Security, Federal Emergency Management Agency, to coordinate all disaster relief efforts which have the purpose of alleviating the hardship and suffering caused by the emergency on the local population, and to provide appropriate assistance for required emergency measures," a FEMA statement said.

Video: Outer Banks residents evacuating

Video: Earl strengthens

Video: Video of Hurricane Earl from space

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Hurricane models have the Category 4 storm passing close to North Carolina's Outer Banks on Thursday night, the National Hurricane Center said.

"A turn toward the north is expected later today ... with a turn toward the north-northeast and a faster forward speed expected on Friday," the Hurricane Center said. "On the forecast track ... the center of Earl will pass near the North Carolina Outer Banks tonight ... and approach southeastern New England Friday night."

The Hurricane Center extended storm watches and warnings northward through Massachusetts Wednesday evening and said the storm's track has shifted slightly to the west, closer to North Carolina's Cape Hatteras.

Officials in Dare County, North Carolina, issued mandatory evacuation orders for visitors to the coastal county Thursday, including the Outer Banks. The mandatory evacuation extended to residents in some areas, including the town of South Nags Head and Hatteras Island. Dare County schools and courts were closed Thursday and will be closed Friday.

"Residents along the oceanfront are advised to relocate due to coastal flooding and ocean overwash that will occur," the county said in a statement.

As of 8 a.m. ET, the center of Earl was located about 355 miles (575 kilometers) south of Cape Hatteras, North Carolina, and about 820 miles (1,315 kilometers) south-southwest of Nantucket, Massachusetts.

Earl's maximum sustained winds have increased to near 145 mph (230 kph), the National Hurricane Center said. It was heading north-northwest at about 18 mph (30 kph).

Tropical storm force winds are expected to reach parts of the North Carolina coast by Thursday afternoon, with hurricane force winds arriving by late Thursday, the Hurricane Center said.

Large breaking waves of 10 to 15 feet are possible along the coast, with possible storm surge of 2 to 4 feet, along with 3 to 4 inches of rainfall, CNN Meteorologist Sean Morris said. Isolated tornadoes and waterspouts are possible.

Tropical storm force winds are expected to reach the coast from Virginia to New Jersey by late Thursday or early Friday. Morris said that Earl will make its closest pass to New Jersey on Friday afternoon as a Category 2 hurricane.

The long duration of tropical storm force winds threaten widespread power outages in parts of the South and the mid-Atlantic region, he said.

Tropical storm force winds will arrive on Massachusetts' Cape Cod by Friday afternoon. Morris said that hurricane force winds are possible there later on Friday, with Earl making its closest pass to Cape Cod on Friday evening as a Category 1 hurricane.

Forecasters have issued a hurricane warning for the area from Bogue Inlet, North Carolina, northeast to the North Carolina-Virginia border, including Pamlico and Albemarle sounds.

On Wednesday evening, a tropical storm warning for the area between Cape Fear, North Carolina, and Bogue Inlet, was extended from the North Carolina-Virginia border to Sandy Hook, New Jersey.

A hurricane watch stretched from the North Carolina-Virginia line up to Cape Henlopen, Delaware, while another hurricane watch covered a chunk of the Massachusetts coast, from Wood's Hole to Sagamore Beach, and includes Martha's Vineyard and Nantucket .

A tropical storm watch extends from Sandy Hook, New Jersey to Wood's Hole, Massachusetts, encompassing Long Island Sound and Block Island. A tropical storm watch also covers the area from north of Sagamore Beach, Massachusetts, to the mouth of the Merrimack River.

Because of Earl's size, effects of the storm are expected to be widely felt. Hurricane-force winds extend outward up to 90 miles (150 kilometers) from the center, and tropical storm-force winds up to 230 miles (370 kilometers).

Earl is expected to make a direct landfall over southern Nova Scotia, Canada, on Saturday morning as a strong Category 1 hurricane.

Federal Emergency Management Agency Administrator Craig Fugate said Wednesday he had briefed President Obama on what the agency is doing in preparation for the storm. Teams are in place or on standby to assist each state along the East Coast, he said, and supplies were being moved into two incident support bases to be available if they are needed.

Several airlines said Wednesday that passengers to and from cities along the eastern seaboard, from San Juan, Puerto Rico, to Bangor, Maine, could reschedule travel in coming days without penalty. Though they have not announced cancellations, Air Tran, American Airlines, Continental Airlines and Delta said they would waive reschedule fees for such travelers.

On Ocracoke Island, North Carolina -- a long sliver of land reachable only by ferry -- not everyone was planning to flee as Earl approached.

"A lot of times when [residents] evacuate, it's hard to get back on the island," said Brandon Benecki, who tends a bar on Ocracoke Island. "It's simpler to just stay here and kind of ride it out."

"None of my neighbors are leaving," one man on Ocracoke Island told CNN affiliate WVEC-TV. "We're just going to hang in and ride her out."

Some tourists didn't seem deterred either. "They'll throw us off the island," one woman told WVEC. "That's all right. We'll just camp somewhere else."

However, Paula Schramel, who co-owns a restaurant on Ocracoke with her husband, Michael, said she has made plans to go to Charlotte, North Carolina, where her mother is. The couple are natives of New Orleans, Louisiana, who moved to Ocracoke 10 years ago.

Some of Michael Schramel's relatives in New Orleans who lived through Hurricane Katrina are urging them to evacuate, she said. "They're probably more nervous than we are," she said. "It wakes you up a little bit to the fact that it can be" dangerous.

Once the wind gets to 50 mph, she said, the ferries stop running and "you're stuck." Officials are "running the ferries as fast as they can," she said, but some visitors are dragging their feet -- understandably, since it means cutting their vacation short.

Earl is also dealing the couple an economic blow, they said, as it's considered the last big week of business for the summer tourism season. The restaurant was busy Tuesday night, Paula Schramel said, but closed on Wednesday once the evacuation order was issued.

"We are concerned about the storm, and it is important that people aren't here who don't understand the [potential] flooding issues," said Alan Sutton, the owner of Tradewinds Bait and Tackle on Ocracoke Island. But for regular residents, he said, the threat of hurricanes is "just part of living here."

Hurricane Earl is approaching the United States just ahead of Labor Day, a holiday weekend that many families spend at the beach.