HAITI -- President Barack Obama warned Americans in the path of Hurricane Matthew to pay attention and take any evacuation orders seriously. He said if the core of the storm strikes Florida, it could have a "devastating effect."
Hurricane Matthew weakened slightly as it headed to the Bahamas on Wednesday.
As of late Wednesday morning, Matthew was hurling 120-mph (193 kph) winds, the National Hurricane Center said. It was about 105 miles (165 kilometers) south of Long Island, Bahamas, and was moving northwest at 12 mph.
It could make landfall in the United States on Friday morning on Florida's east coast, CNN meteorologist Dave Hennen said.
Hurricane Matthew likely won't strike the US for another day -- but after seeing its deadly, devastating impact in the Caribbean, authorities are urging residents to get ready.
"I cannot emphasize enough that everyone in our state must prepare now for a direct hit," Florida Gov. Rick Scott said Wednesday.
"That means people have less than 24 hours to prepare, evacuate and shelter. Having a plan in place could mean the difference between life and death."
Matthew hurled winds of 125 mph as it churned toward the Bahamas on Wednesday. Forecasters predict it will strengthen to a Category 4 hurricane by the time it pummels Florida, Georgia, South Carolina and North Carolina sometime between Thursday evening and Saturday.
The National Hurricane Center said the storm could make landfall in any of those states.
It's not just Florida's governor giving dire warnings. South Carolina Gov. Nikki Haley has given evacuation orders for the coastal counties of Charleston and Beaufort starting at 3 p.m. Wednesday.
Florida braces for 'direct hit'
Gov. Rick Scott declared a state of emergency for the entire state and warned that a direct hit by Matthew could lead to "massive destruction" on a level unseen since Hurricane Andrew devastated the Miami area in 1992.
The top priority, Scott said, would be to ensure that Florida did not add to Matthew's death toll, which has already climbed to at least 10 in the Caribbean.
Scott told reporters Tuesday that evacuation orders could be imminent.
Brevard County commissioners ordered one of the state's first mandatory evacuations for residents of Merritt Island and other barrier islands. Residents are being ordered to leave starting 3 p.m. Wednesday.
CNN forecasters predict the storm could hit parts of Florida starting Thursday night.
The effects of the incoming storm have already been felt at gas stations in south Florida. CNN affiliate WSVN reported long lines at gas pumps at a Costco in North Miami Beach.
"I'm just waiting my turn," one woman told WSVN from her car. "I know it'll be worse tomorrow."
In Juniper, Florida, resident Randy Jordan told CNN affiliate WPEC people were pushing and shoving their way through the local Home Depot to buy supplies ranging from batteries to flashlights.
"The vibe on the street this morning is pre-panic," Jordan said. "By tomorrow, it should just be a brawl."
Mandatory evacuations South Carolina
The threat in South Carolina is so severe that schools and government offices in 25 counties are closed Wednesday. Some schools will double as evacuation shelters.
In addition to the evacuation orders for Charleston and Beaufort counties Wednesday afternoon, Gov. Haley ordered Horry and Georgetown counties to evacuate by Thursday morning.
The South Carolina Department of Transportation has started changing the directions of traffic lanes to accommodate the exodus of people leaving coastal cities like Charleston.
By 3 p.m. Wednesday, lanes on Interstate 26 will also be reversed to help residents flee.
North Carolina tourists sent packing
Gov. Pat McCrory declared a state of emergency for more than half of the state's 100 counties.
And North Carolina tourists have been told to cut their vacations short.
State emergency officials said they expect up to 8 inches of inches of rain and brutal winds starting Friday.
"Many of our central and eastern counties are already saturated from storms during the past few weeks," North Carolina Emergency Management Director Mike Sprayberry said.
"We are preparing for additional flooding, downed trees and widespread power outages in the coming days."
Authorities in Hyde County have issued a mandatory evacuation order for Ocracoke Island, a popular tourist destination.
The University of North Carolina-Wilmington has also ordered students to evacuate no later than noon Thursday.
Georgia governor: 'Remain calm but vigilant'
Georgia Gov. Nathan Deal has declared a state of emergency in 13 coastal counties.
"We urge residents in these areas to remain calm but vigilant as they prepare for potential impact," Deal said.