Editor's Note: Check out "Open Story: Hurricane Irene," a collaborative effort of CNN and iReport contributors who are documenting the storm as it moves across the Atlantic Ocean. Read more about Hurricane Irene from CNN affiliate WBOC.

By Ed Payne, CNN

Miami (CNN) -- Vacationers and residents prepared to evacuate North Carolina coastal areas on Thursday morning as Hurricane Irene roared toward the United States, where it's expected to hit this weekend.

The powerful Category 3 storm, now battering the Bahamas with sustained winds of 115 mph, is forecast to pound much of the eastern United States starting early Saturday.

Janeen Wall bolted before the storm, leaving less than a day after arriving at her Carolina Beach, North Carolina, accommodations.

"Since the second floor condo I was staying in is very close to the beach, I didn't really want to take my chances with a hurricane blowing into town," the Richmond, Virginia, resident said after making the five-hour drive back home.

"Also, if I waited for an evacuation order, I would have to share the road with more than a few thousand other folks trying to leave at the same time."

The mandatory evacuation order for Dare County, North Carolina -- home to Manteo, Nags Head, Duck and historic Kitty Hawk -- is only for tourists.

Residents can stay for now, but emergency officials have put them on notice.

Neighboring Hyde County declared a state of emergency for low-lying coastal plains, with evacuation orders in place starting Thursday morning.

With Irene still more than 700 miles south of Cape Hatteras, the National Hurricane Center issued storm warnings for sections of the Carolinas.

A hurricane watch is in place from north of Surf City, North Carolina, to the border with Virginia. A tropical storm watch was put up from Surf City south to Edisto Beach, South Carolina.

Irene is expected to strengthen to a Category 4 storm Thursday with winds in excess of 130 mph.

Irene pounded the central Bahamas early Thursday, whipping the island chain with gusts of up to 150 mph, a Hurricane Center advisory said.

As it stomped across Bahamas, the storm left a trail of destruction.

"Homes losing their rooftops, churches being destroyed," said Capt. Stephen Russell of the nation's emergency management department.

Officials are waiting the light of day to assess the full scope of the damage on the 500-mile long island chain.

In the capital, Nassau, businesses boarded up windows as tourists flocked to the airport and cruise ships pulled out of port ahead of Irene's arrival.

Early Thursday, CNN's Jim Spellman reported "punishing, pounding winds" as it approached. He said he had not seen any major damage.

In the Hurricane Center's 5 a.m. advisory, Irene was 80 miles east-southeast of Nassau.

Rainfall of 6 to 12 inches was expected across the Bahamas, the Hurricane Center said.

As the storm clears the Bahamas, it is expected to curve northward and then to the northeast as it nears the United States, with the latest projections suggesting the storm will skim the North Carolina coast Saturday morning.

South Carolina state officials have decided not to order evacuations, but urged boaters and swimmers to stay out of the water.

Storm preparations were less intense along the Virginia coastline and the Eastern Shores of Maryland -- the area swamped by Hurricane Isabel in 2003.

One resident was hopeful that Irene would pass close by.

"Dear Irene, please bring rain. Thank you," read a handwritten sign on a mailbox near Hampton Roads, Virginia, where a stubborn wildfire has been burning in historic Dismal Swamp.

"Hurricane Irene may be the only way to get enough rainfall to assist the firefighters and put this relentless fire out," said Penelope Penn.

Harold Barkley of Virginia Beach took the calm day before the storm to clean out his car, while keeping a wary eye on news reports.

"I have been watching the TV -- both the local and national TV weather services," Barkley told CNN affiliate WTKR-TV. "And I have thought very seriously about it, if I need to stay here or whether I need to get out."

He's never had to evacuate his home in the 35 years he's lived there.

In Crisfield, Maryland, 80 miles to the north, Ginger Wilson said her family will stay put as Irene approaches this weekend.

"We'll probably have some extra water, get some canned vegetables and foods, and make sure the pantry is full," she told CNN affiliate WBOC-TV. "Just have any extra supplies -- batteries, radios, anything that would be helpful."

The Hurricane Center's forecast map has Irene hugging the coast from the Carolinas to New York, before slicing through much of New England and into the Canadian Maritimes.

"Everywhere from North Carolina to Massachusetts remains in the cone of uncertainty," CNN meteorologist Jacqui Jeras said. "Even if Irene doesn't make landfall in the United States, it may very well bring flooding rains, damaging winds and power outages to the Northeast."

The last major hurricane to strike the United States was Wilma in 2005, which was a Category 3 at landfall, Jeras said.

Hurricane Katrina, earlier the same year, was also a Category 3 at landfall. The most recent hurricane to make landfall in the United States was Ike in 2008, which hit near Galveston, Texas, as a Category 2.

Irene is expected to pass well east of Florida, so only minimal effects are expected Thursday and Friday as the storm moves northward.

But the U.S. Coast Guard is worried boaters in south Florida are taking the threat too lightly.

Officials expect heavy rip currents and beach erosion in Miami.

We recommend

CNN's John Fricke, Phil Gast and Josh Levs contributed to this report.