(AP) -- Florida canceled classes along its Atlantic coastline and theme parks kept a watchful eye as Hurricane Matthew picked up speed heading to the East Coast.

Officials in central Florida's Brevard County are ordering residents on barrier islands and in flood-prone areas to evacuate Wednesday in advance of the powerful hurricane. Residents who live in mobile and manufactured homes also are being ordered to leave.

In South Carolina, Gov. Nikki Haley contemplated whether to order some 1 million people to leave the coast and planned to release details of her plan Wednesday morning.

The evacuation is scheduled to take effect at 3 p.m., but traffic already was bumper-to-bumper during morning rush hour on Interstate 26 as people fled ahead of the storm. Gasoline was hard to come by during morning rush hour, with at least half a dozen stations in Mount Pleasant out of fuel and lines at others. The state's attorney general warned stations against price gouging.

In Florida, a message on Walt Disney World's website Wednesday says all of its theme parks and resorts are "currently operating under normal conditions" as officials continue to monitor the storm. They advised those who plan on visiting Disney to monitor news outlets for the latest weather information.

Officials at SeaWorld in Orlando announced on its website that officials "anticipate altered hours due to Hurricane Matthew."

Government officials are worried about complacency, especially in South Florida, which hasn't seen a major hurricane in 11 years.

In Miami-Dade County, the state's largest school district, officials said they'll monitor the storm on Wednesday morning before making a decision on whether to cancel classes Thursday and Friday. The county remains under a tropical storm warning.

From Broward County to the Space Coast -- where hurricane warnings are in effect -- officials already have closed schools for the rest of the week. Some school districts are sending students home early on Wednesday, and after school activities are canceled.

Most colleges and universities in the warning areas also have canceled classes starting Wednesday evening.

A dangerous Category 3 storm with sustained winds of 115 mph, Matthew was bearing down on the southern Bahamas early Wednesday and expected to be very near Florida's Atlantic coast by Thursday evening. Already the hurricane was spreading high winds, heavy rain and a dangerous storm surge ahead of it as it neared the Bahamas.

The National Hurricane Center in Miami said Matthew -- recently a Category 4 storm and at one brief point a fierce Category 5 -- will remain a powerful storm at least through Thursday night. It added that while maximum winds decreased slightly in recent hours, the fluctuation in intensity was expected and some slight strengthening is forecast in coming days.

Officials hope to avoid a repeat of Hurricanes Wilma and Katrina, which caused major damage to South Florida in 2005, and Hurricane Andrew, a Category 5 storm, leveled much of the city of Homestead in 1992.

The Miami forecasters issued a hurricane warning for the area north of Golden Beach near Fort Lauderdale to Sebastian Inlet, meaning hurricane force winds of 74 mph or higher are expected within two days. A hurricane watch is also in effect from Sebastian Inlet to Fernandina Beach, meaning hurricane force winds could occur.

In South Florida, lines at grocery stores were heavier than usual on Tuesday and some essentials were in short supply. When Simone Corrado and her husband tried to buy water at their Publix in Davie near Fort Lauderdale, they mostly found empty shelves. There were a few bottles of high-end water brands, but there was so much empty shelf space that Corrado lay down and fully stretched out on the bottom shelf.

"I got scared because all that was left at Publix was just the pricey water," said Corrado, who lived through 1992's catastrophic Hurricane Andrew, which practically leveled the nearby city of Homestead. "They really put the fear into you here. On the television screen every few minutes is the 'beep, beep, beep' storm alert."

In a news release, Brevard County's board of commissioners said mandatory evacuations will begin at 3 p.m. Wednesday in Merritt Island and other areas. County officials say shelters will begin opening at 4 p.m. In addition, officials Brevard County said Cape Canaveral Hospital near the coast began moving patients to inland hospitals.

Hurricane Hermine became the first to strike Florida since Wilma in 2005 when it hit the eastern Panhandle on Sept. 2 as a Category 1 storm, causing one death, storm surge damage to beachfront homes and downed trees and powerlines. That 11-year lull between storms hitting Florida was the longest on record.

The last storm to hit Florida from the Atlantic side was Katrina, which struck on its way to devastating the Gulf coast.

Wilma made landfall as a Category 3 storm with 120 mph winds, killing five people as it pushed from southwest Florida, through the Everglades and into the Fort Lauderdale and Palm Beach area, causing an estimated $21 billion in damage and leaving thousands of residents without power for more than a week. It concluded a two-year span when a record eight hurricanes hit the state.

Governors in Florida, Georgia, South Carolina and North Carolina declared states of emergency, and the White House said President Barack Obama canceled a campaign and health care events in Florida on Wednesday.

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Kay reported from Miami Beach. Associated Press reporters Jeffrey Collins, Jack Jones and Meg Kinnard in Columbia, South Carolina; Bruce Smith in Charleston, South Carolina; Mike Schneider in Orlando, Florida; Freida Frisaro in Miami and Martha Waggoner in Raleigh, North Carolina, contributed to this report.

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Follow Terry Spencer on Twitter at https://twitter.com/terryspen

His work can be found at http://bigstory.ap.org/author/terry-spencer