North Carolina Governor Roy Cooper declared a state of emergency as well as mandatory evacuation orders along the eastern coastline.
The National Hurricane Center says the storm is gathering power as it moves towards land, and "is expected to be an extremely risky major hurricane" by Thursday.
The National Hurricane Center's projected track for Hurricane Florence, as of 11 a.m. on September 11, 2018.
"The chances of it going out to sea are extremely slim at this point", she said.
If the storm stalls, some areas could see feet of rain, especially if downpours focus over the higher terrain in western North Carolina and southwestern and central Virginia Authorities said such volume could cause flash floods, mudslides, and other risky conditions.
The entire southern East Coast of the United States is bracing for the arrival of Hurricane Florence as the storm approaches.
For many people, the challenge could be finding a safe refuge: If Florence slows to a crawl, it could bring torrential rains into the Appalachian mountains, causing flash floods and mudslides across a region getting lots of rain recently. "Don't wait", said Greg Postel, a hurricane expert at the Weather Channel.
"It's not just the coast", Mr Graham said.
Hurricane-force winds extend outward up to 35 miles from the center and tropical-storm-force winds extend outward up to 140 miles. Any Category 3, 4 or 5 hurricane is classified as a major hurricane. To say that it looks intimidating would probably be a massive understatement. A "Hurricane Hunter" aircraft recorded maximum sustained winds of 130 miles per hour. "Florence has rapidly intensified into an extremely risky hurricane", Blake wrote Monday evening that top sustained winds would approach the 157 miles per hour (253 kph) threshold for a worst-case Category 5 scenario.
The hurricane will pose a pretty serious threat to the East Coast and is expected to produce winds of around 140 miles per hour as it makes landfall. While Helene is forecast to slide out to sea away from land, Isaac is a very real threat in the Caribbean later this week, the hurricane center said.
Florence appears to have weakened slightly but is expected to restrengthen later on Tuesday, the NHC said.