The first tropical storm-force winds of at least 39 miles per hour (63 kph) were forecast to hit the coast on Thursday.
The NHC stressed, however, that while a slow weakening is expected over the next 24 hours "Florence is still forecast to be an extremely risky major hurricane when it nears the U.S. coast late Thursday and Friday".
While a man who gave his name as Joe, a contractor from Carolina, admitted he was "scared" but said he had survived storms before and was determined to make it through this one.
"Do you want to get hit with a train or do you want to get hit with a cement truck?" said Jeff Byard, an administrator with the Federal Emergency Management Agency. Eventually, Florence will veer north into the Appalachian Mountains, bringing soaking rains to Virginia and western North Carolina, before sputtering out late next week near DE and Maryland, the FWS reported.
Duke Energy, the second-largest energy company in the United States, said Florence could knock out electricity to three-quarters of its four million customers in the Carolinas.
In a news release Wednesday, Gov. Nathan Deal says the state "is mobilizing all available resources to ensure public safety ahead of Hurricane Florence". "Now it might be time for the exam", Baxley said late in the morning.
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.
CBS News correspondent David Begnaud reports that people living in the barrier island community of Wrightsville Beach, North Carolina, are bracing for a possible direct impact.
Data collected during the flight allows the NOAA to keep a watchful eye on the most powerful storm to date in the 2018 Atlantic hurricane season, to research its speed, intensity and structure.
"We hope to have something left when we get home", she said. Although North Carolina is still expected to see the worst of the storm, a more southern track would mean that states further north - like Virginia - could be spared of some nasty weather. Most other beachgoers were long gone.