The storm is moving toward the northwest at 17 miles per hour, the NHC said.
By late Thursday afternoon, the Carolina coasts can expect winds topping 80 miles per hour. "We have a day off. Let's get drunk!'" Jordan Berry, the barman at a local sports bar, told the site.
The hurricane center also said the threat of tornadoes was increasing as Florence neared shore and South Carolina Governor Henry McMaster said the heavy rains could trigger landslides in the western part of his state. "We are totally prepared", Trump said at the White House.
The scale includes five categories and is based on the storm's sustained wind speeds.
The forecasters say the slow speed will give Florence time to pound the Carolinas with bands of heavy rain. The trend is "exceptionally bad news", said University of Miami hurricane researcher Brian McNoldy, since it "smears a landfall out over hundreds of miles of coastline, most notably the storm surge".
Hurricane Florence, they found, will grow about 50 miles (80 kilometers) larger and will dump 50 percent more rain over a period from September 11 to September 16 than it would have in a world before climate change.More news: Georgia Baptist university cuts ties with Nike over Kaepernick ad
By the time it leaves, it's expected to have unloaded 10 trillion gallons of rainfall in North Carolina, weather.us meteorologist Ryan Maue said. That's enough to fill more than 15 million Olympic-size swimming pools.
"It's cumulative damage", Myers said. "Then, a long time later, they started to report really large numbers, like 3000". Fallen trees and power poles will isolate residential areas. Also, the hurricane-force winds and tropical storm-force winds have been expanding.
The storm is expected to affect airports in Georgia and Virginia.
The evacuations continued as Florence weakened a bit in its charge towards the East Coast, downgrading from a Category 3 storm to a Category 2, the National Hurricane Center said in its latest update. It was forecast to make landfall Friday morning or afternoon near Cape Fear, North Carolina, bringing up to 40 inches (1 meter) of rain in places. Once projected to make landfall as a Category 4 storm with the potential to reach Category 5, forecasters now believe Flo will hold at least a Category 2 rating as it approaches land.
In Virginia, where about 245,000 residents were ordered to evacuate low-lying areas, officials urged people to remain away from home despite forecast changes showing Florence's path largely missing the state.
"It doesn't matter where you are", he said.More news: Lexus ES gets new side mirrors
"It's just extremely busy and it's even busier than previous year and all at once", Blake said. All seven of North Carolina's ferry routes were shut down.
Mayor Joe Benson said the storm will batter the oceanside town through two high-tide periods.
But the biggest danger could be life-threatening storm surges.
In yet another reminder to those in the path of the storm, it's worth noting that Trump also said the response to last year's hurricane in Puerto Rico - which officially killed almost 3,000 people - had been "incredibly successful". "Flooding is nearly guaranteed".
Browning's choice to stay in the hurricane warning zone wasn't easy, she said, but she "could not find anywhere to go". She packed up what she could and took a ferry Tuesday night.
The Federal Emergency Management Agency warned that storm surge watches and warnings are in effect Wednesday for the entire North Carolina coast and parts of SC.More news: It's the end of the road for Inbox by Gmail