 -- Hurricane Matthew made landfall on the eastern tip of Cuba Tuesday night after tearing through Haiti earlier in the day and officials were making preparation for coastal evacuations in the U.S. ahead of the massive storm's arrival there.

The storm continues to be classified as a Category 4 hurricane, with winds of up to 140 mph as it moves north at 6 mph. On Wednesday, it is expected to make a northwest turn and head through the Bahamas, with hurricane force winds extending 45 miles away from the center of the storm.

"We will get full impact," said Bahamian Director of Crisis Management, Geneva Cooper.

The hurricane made landfall in Haiti this morning, lashing the western shores of the country with 145 mph winds and causing thousands of Haitians to seek emergency shelter.

Forecasters predict it could reach the United States and brush Florida by Thursday morning.

South Carolina Gov. Nikki Haley declared a state of emergency today and has begun medical evacuations for residents living along the coast.

She said that all coastal communities in South Carolina -— about 1.1 million people -— will be asked to evacuate tomorrow.

Schools and government offices will be closed tomorrow in South Carolina, and Haley recommended that residents move at least 100 miles from the coast.

Florida Gov. Rick Scott warned that the storm "could bring devastation to Florida [that] we haven't seen in years," adding that "we cannot rule out a direct hit on Florida" starting as early as Wednesday. He declared a state of emergency in anticipation of the storm.

He said that the effects of Matthew could be "catastrophic," bringing with it a chance of heavy rain, rip currents, beach erosion, tornadoes and hurricane-force winds.

Mandatory evacuations for Brevard County, on the east coast of central Florida starting Wednesday at 3 p.m., and shelters will begin opening about an hour later, city officials announced. Public schools and government offices will be closed Thursday and Friday.

The National Hurricane Center has heightened the status of Hurricane Matthew for Broward County, Fla., to a Hurricane Watch, said Broward County Mayor Marty Kiar. The county plans to open shelters on Wednesday for children with special needs and residents with pets. The county's schools will be closed Thursday and Friday.

"This is serious, and our residents need to take this seriously as well," Kiar said. A Hurricane Watch has been issued for Lake Okeechobee as well.

In neighboring Miami, the mayor, Carlos Gimenez, said there are no plans yet to evacuate the city but residents should brace themselves for possible danger from the storm.

"The message is simple," Gimenez told reporters of his message to the city's residents. "You should be prepared."

Further north, Georgia Gov. Nathan Deal declared a state of emergency for 13 counties this afternoon in anticipation of Hurricane Matthew.

In Haiti, some 6,000 people were being housed in temporary shelters, the country's civil protection service said on Twitter. Many more remained in flood-prone areas.

"Life-threatening flash floods and mudslides are likely from this rainfall in southern and northwestern Haiti, the southwestern Dominican Republic and eastern Cuba," the National Hurricane Center said in an advisory.

Some 10.6 million people were in the storm's path in Haiti, according to the United Nations, in addition to 11.2 million in Cuba and 2.8 million in Jamaica.

Citing "life-threatening rains, winds and storm surges," USAID released $400,000 in initial assistance to mount a humanitarian response to the storm.

North Carolina Gov. Pat McCrory declared a state of emergency for 66 counties in his state in anticipation of Matthew's arrival Thursday night. He said he has been in contact with FEMA to prepare for the storm.

"I'm hoping this is a false alarm, but we can't gamble," he said.

A FEMA representative said the storm is being monitored very closely, adding that the agency is in touch with officials in potentially affected states.

"It's too soon to know what impact, if any it, will have on the U.S., but we're urging individuals to take advantage of the time they have right now to prepare," the representative said.

ABC News' Catherine Thorbecke, Daniel Manzo, Samantha Wnek, Erin Dooley and Melissa Griffin contributed to this report.