The state of South Carolina is preparing to evacuate more than 1 million people as the nation girded for Hurricane Matthew, the most powerful storm to smash through the region in almost a decade.

A hurricane watch was issued Tuesday for parts of Florida as Matthew roared through the Caribbean, pounding tiny Haiti with heavy rain and powerful winds and tides. Hurricane-strength winds could reach Florida midday Thursday, and the storm could linger there into Friday, National Hurricane Center spokesman Dennis Feltgen said.

Feltgen said it was too soon to determine the impact as the storm then continues it's march north.

Florida Gov. Rick Scott warned residents to prepare for power outages and evacuations. South Carolina Gov. Nikki Haley ordered evacuations of some coastal communities. The numbers had not been determined, but state emergency management officials said the total could exceed 1 million.

"This is not something that we want to play with," Haley said. "The worst-case scenario is that you get stuck on the coast and have no place to go."

The Category 4 hurricane made landfall in Haiti on Tuesday with top sustained winds near 145 mph. The latest computer models predicted a path edging closer to the U.S. East Coast, the hurricane center reported.

"We still have the core (staying) off the Florida coast," Feltgen said. "But our present track does bring the possibility of hurricane force winds to Florida."

Feltgen said it was too early to determine a timeline or impact along the rest of the East Coast as Matthew sweeps north. At 2 pm ET on Tuesday the storm was 65 miles east-southeast of Guantanamo Bay, Cuba, and was moving north at about 10 mph.

A hurricane warning remained in effect for all of Haiti and portions of Cuba and the Bahamas. At least seven deaths already were reported. Matthew is the strongest hurricane to hammer the region since 2007, when Felix reached Category 5 status with sustained winds of 160 mph and killed more than 130 people, most in Nicaragua.

In Florida, a hurricane watch was in effect from Deerfield Beach, Fla. to the Volusia/Brevard county line in Central Florida. A tropical storm watch was in effect from the Seven Mile Bridge in the Florida Keys northward to the hurricane watch area.

John Pendergrast, a meteorologist with the National Weather Service in Melbourne, warned that the storm continues to remain unpredictable but said Matthew "looks like it’s going to be a close brush."

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