The National Hurricane Center announced Florence was increased to a Category 4 hurricane Monday morning, with a projected path toward the Carolinas. The National Hurricane Center is now expecting the center of the storm to move between Bermuda and the Bahamas on Tuesday and Wednesday.
Forecasters cautioned, though, Florence could impact anywhere from northern Florida to north of the Washington, D.C., area. These swells are likely to cause life-threatening surf and rip current conditions.
Hurricane Florence - which formed as a tropical depression in the Atlantic Ocean on August 31 - is now a Category 4 on the Saffir-Simpson scale, which measures hurricane strength from 1 to 5.
Winds of tropical storm force could reach Puerto Rico Thursday evening.
By 5 a.m. Tuesday, Florence was centered about 975 miles (1,570 kilometers) east-southeast of Cape Fear, North Carolina, and moving west-northwest at 15 mph (24 kph). As you can see, the earliest time that tropical storm winds are now expected in the Carolinas, according to the National Hurricane Center, is Wednesday night.
Forecasters say the hurricane's strength is expected to fluctuate but it still will be a risky storm by the time it reaches the coast of SC or North Carolina on Thursday.
McMaster ordered the evacuation of coastal areas to start at noon on Tuesday as Hurricane Florence approaches.
Two other hurricanes - Isaac and Helene - have also formed in the Atlantic Ocean.
More than 400 hundred officers from the South Carolina Law Enforcement Division will be stationed in the coastal areas to help assists evacuation and protect property.
This GIF from the National Oceanic and Atmospheric Administration shows three hurricanes - Florence, Isaac and Helene - as they make their way across the Atlantic Ocean. During that time, 40 to 70mph sustained winds are possible with hurricane force gusts up to 80mph.
The NHC also says the storm could become more powerful.
North Carolina Gov. Roy Cooper said his state is "in the bullseye" and urged people to "get ready now". The hurricane caused an estimated $90 billion in damage there and on the U.S. Virgin Islands, making it the third-costliest hurricane in American history.