The focus of preparations for Hurricane Irene moved up the Carolinas coast Tuesday, with forecasters now saying the worst of the storm will slam into the Outer Banks.

Most of the Carolinas would escape a major impact from the storm, which is predicted to make landfall on the North Carolina coast sometime after noon Saturday. But meteorologists at the National Hurricane Center once again reminded the public that the forecast track of the storm could shift in either direction.

While Irene, which was battering the southern Bahamas on Tuesday night, is expected to remain at least 100 miles off the South Carolina coast, authorities in the Palmetto State continued their planning for the hurricane.

But activity was ramped up in coastal North Carolina. A mandatory evacuation order will go into effect Thursday morning on Ocracoke Island, a 16-mile-long barrier island off the Outer Banks. Other evacuations are possible, but officials say they want more information on which way the storm will move.

At 5 p.m. Tuesday, the center of Hurricane Irene was at 20.9 degrees north and 71.5 degrees west, of 80 miles south-southwest of Grand Turk Island. The storm had 90 mph sustained winds and was moving west-northwest at 9 mph. Irene's winds dropped 10 mph Tuesday afternoon, and westerly shear cut into the storm's circulation.

But Daniel Brown, of the National Hurricane Center, said the westerly wind will end by early Thursday, allowing Irene to intensify, possibly to Category 4 status with 125 mph winds as it moves over the northern Bahamas.

Landfall was predicted for Saturday afternoon, somewhere along the Outer Banks.

Some would-be coastal vacationers were canceling reservations Tuesday, according to Steve Long, owner of the Golden Sands Motel in Carolina Beach, south of Wilmington.

"Everybody is kind of wait-and-see, but those who do have reservations for the weekend are canceling," he said. "Since it was going east all day yesterday, we hope it keeps pushing that way."

Farther to the north, Dare County officials said they were ready.

"All the plans we have are in place," said Sandy Sanderson, the emergency management director. "All the people are in place. We are primed and ready to move if we have to."

Kimberly Miles, of the Myrtle Beach Area Chamber of Commerce, said vacationers along the Grand Strand also are taking the wait-and-see approach.

"We've gotten some calls today from people asking whether they should change their plans, but the majority of people haven't actually canceled anything yet," Miles said.

"We're advising people to call their hotel, check on the policy at the hotel, and the same thing with the airlines," Miles added.

The same cautious approach was being displayed by Grand Strand-area residents.

"It's not a rush or a mad dash," said Mike Hemingway, manager of a Lowe's home improvement store in Myrtle Beach. "Everyone is doing pretty much a wait-and-see."

The governors of the two states said their emergency management teams are ready.

"We will be ready if Hurricane Irene reaches North Carolina," Gov. Bev Perdue said in a late-afternoon news conference. "Our teams are already lining up supplies, trucks and resources to reach anywhere the storm might reach."

South Carolina Gov. Nikki Haley said emergency management officials were in contact with county and federal officials and were prepared.

Hurricane Irene was moving west-northwest Tuesday evening, but forecasters expect a turn to the northwest and eventually the north. That would keep the storm well off the Florida coast and also at least 100 miles off the South Carolina coast.

"The biggest uncertainty we have is the timing of the turn to the north and eventually the northeast," said Bill Reed, director of the National Hurricane Center.

Hurricane warnings were in effect for the Turks and Caicos islands, and for the Bahamas. Forecasters say the Bahamas stand to feel the worst of the hurricane.

The storm's expected impact on the Charlotte region lessened considerably as Irene's predicted path was moved eastward. If it makes landfall near the Outer Banks, the heavy rain and winds will be limited to the eastern third of the Carolinas.

South Carolina has not been hit by a hurricane since 2004, and the last major hurricane in North Carolina was Isabel, in 2003.

In Horry and Georgetown counties on the S.C. coast, officials said they were ready.

Sam Hodge, of Georgetown County Emergency Management, said officials have met with county leaders and school officials about what the school system would do -- including the possibility of postponing high school football games on Friday night.

"We're waiting to see what happens," Hodge said.

Randy Webster, of Horry County's emergency management operations, said Irene "could be dangerous. We just want people to recognize the threat."

South Carolina officials said they have plans ready, in case large-scale evacuations are required.

The (Myrtle Beach) Sun News and the Associated Press contributed.