With hundreds of thousands of people streaming inland, Hurricane Matthew today lurked just off the eastern coast of Florida and trained its sights on Georgia.

More than 2 million people in Florida, Georgia and the Carolinas are under mandatory evacuation orders. Many of the nearly half-million people living in Georgia's six coastal counties were heading west on I-16 or on U.S. 341 into the state's interior. Thousands sought refuge at Red Cross and other shelters across the state. Late Thursday, President Barack Obama declared a state of emergency in Georgia and ordered federal aid to supplement state and local efforts.

Matthew was downgraded from Category 4 to Category 3 overnight, but it remains exceedingly dangerous and is expected to strengthen as it churns northward. Forecasts are calling for up to 14 inches of rain along the Georgia coast.

Glynn County authorities Thursday spoke in almost apocalyptic terms of the chances for devastation on St. Simons and Jekyll Islands.

A statement from county officials said Matthew could turn into a 500-year event with 9-foot storm surges carrying 25-foot waves.

“Under the current forecast,” Glynn officials said in a prepared statement, “total devastation of the barrier islands is possible and portions of F.J. Torras Causeway and Jekyll Island Causeway may be completely lost.”

A heavy rain began around 8:30 a.m. on St. Simons Island, now a ghost town. Many of the stores here are shuttered, boarded up or lined with sandbags.

Forecasters predicted that Matthew would arrive in force in Georgia late tonight or early Saturday. The National Hurricane Center predicted it would be a Category 2 hurricane (maximum of 110 mph winds) when it strikes the Georgia coast.

The storm, which killed at least 280 people throughout the Caribbean, was centered 70 miles southeast of Jacksonville Beach, Fla., at 1 p.m. today, the National Hurricane Center said. Maximum sustained winds were 120 mph, and the center extended its hurricane warning from Cocoa Beach, Fla., to Surf City, N.C.

Florida Gov. Rick Scott warned Florida residents not to let down their guard. The storm has not delivered the knockout punch in Florida that everyone feared, but it’s far from over and could yet turn west and hit Florida and Georgia directly.

Gov. Nathan Deal ordered the mandatory evacuation of portions of the six coastal counties and closed the eastbound ramps of I-16 near Dublin so westbound traffic could use those, too.

Chris Riley, the governor’s chief of staff, said today that authorities would “press the message that residents who ignore the mandatory evacuation put our first responders in harm’s way. We have activated 320 national guard soldiers and will probably call more into duty today.”

The governor planned a press briefing at 12:30 p.m.

In other developments:

  • More than 4,500 flights were canceled Friday, including every flight to and from Orlando. The big theme parks — Disney World, SeaWorld and Universal — all closed because of the storm.
  • By Friday, the state Department of Corrections had moved 1,543 inmates from Coastal State Prison outside Savannah, as well as from a nearby halfway house, to other prisons not in the storm's path.
  • Saturday's Georgia-South Carolina game was pushed into Sunday in Columbia, with an expected 2:30 start time.
  • The state Department of Transportation said it would close the Talmadge Memorial Bridge at noon today. The Sidney Lanier Bridge on Ga. 25 in Brunswick is already blocked off.

‘I told them I wasn’t going anywhere’

In St. Marys this morning, James Wilson of Kingsland watched the rain and wind gathering strength before dawn from the balcony outside his room at the Cumberland Kings Bay Lodge.

The southern tip of Georgia’s coast is included in a mandatory evacuation zone.

“Everybody else wanted to leave but I told them I wasn’t going anywhere,” he said.

The streets of St. Marys were largely empty, though there were cars in motel and apartment parking lots and in a number of driveways. Many shops had their windows taped and few businesses other than Wilson’s motel were open.

“I’m mad it’s raining,” he said. “I really want to get some coffee.”

Georgia has not had a direct hit from a hurricane in more than a century, and the mandatory evacuation order came a day after Deal expanded a state of emergency from 13 to 30 counties in the southeastern region of the state.

Georgia’s state of emergency covers Appling, Atkinson, Bacon, Brantley, Bryan, Bulloch, Burke, Camden, Candler, Charlton, Chatham, Clinch, Coffee, Echols, Effingham, Emanuel, Evans, Glynn, Jeff Davis, Jenkins, Liberty, Long, McIntosh, Pierce, Screven, Tattnall, Treutlen, Toombs, Ware and Wayne counties.

‘My first hurricane and my last hurricane’

In Brunswick, a bleary-eyed Diane Najar ambled around a motel lobby this morning and made a firm declaration.

“This is my first hurricane and my last hurricane,” said Najar, originally from El Paso, Texas. “I’m leaving.”

Najar and her husband got a condo on St. Simons a year and a half ago and were supposed to be there five years. The couple has been at a Brunswick motel since Wednesday night with two changes of clothes.

Najar was already worried about the storm, but a 5 a.m. phone call left her more concerned.

A friend who works at Brunswick’s Southeast Georgia Hospital said they’d evacuated the hospital at 7 p.m. Thursday.

Another thing is making her anxious: She doesn’t know how to swim.

“I’m afraid it’s going to be another Katrina,” she said.

AJC reporters on the Georgia coast are live-tweeting the storm: Follow @dchapmanajc, @JeremyLRedmon and @FitzTrubey.