How severe the impact is on the Charlotte area will depend on exactly where Florence - now a Category 4 storm - makes landfall and what track it takes inland, National Weather Service forecasters say.
As of Sunday night, the hurricane was centered in southeast Bermuda and moving west at 7 miles per hour.
As of Saturday evening, Florence was a tropical storm that was traveling west at 6 miles per hour with sustained winds of 70 miles per hour. "Theses swells will result in life-threatening surf and rip currents".
"Florence is expected to be an extremely risky major hurricane through Thursday", the NHC said in a bulletin.
In announcing his evacuation order, South Carolina Gov. Henry McMaster said an estimated 1 million people would be fleeing the coast.
It said Florence, a Category 4 storm on the five-level Saffir-Simpson hurricane scale, could approach the coast of SC or North Carolina on Thursday.
Parts of the Carolina coast could begin feeling significant impacts from the storm as early as Wednesday night.
Preparations for Florence were intensifying up and down the densely populated coast.More news: The unraveling of 'Crazytown' White House
U.S. President Donald Trump, whose administration was criticized as being slow to respond to Hurricane Maria in Puerto Rico a year ago, canceled a political rally planned for Friday in Jackson, Mississippi, over safety concerns related to Florence, his campaign said.
The storm's potential path also includes half a dozen nuclear power plants, pits holding coal-ash and other industrial waste, and numerous eastern hog farms that store animal waste in massive open-air lagoons.
"We here in North Carolina are bracing for a hard hit", Cooper said Monday.
North Carolina ordered evacuations for the Outer Banks barrier islands, including popular tourist destination Hatteras Island.
Florence continues to become a better organized storm, with a familiar buzz-saw appearance from satellite shots.
A warm ocean is the fuel that powers hurricanes, and Florence will be moving over waters where temperatures are peaking near 85 degrees, hurricane specialist Eric Blake wrote.
"This is a very unsafe hurricane", McMaster said, adding that the evacuation order for coastal counties was "mandatory, not voluntary".
Florence could be a Category 4 storm when it approaches North Carolina on Thursday.
The Navy said all ships in Virginia's coastal Hampton Roads area were preparing to leave port for open seas. After passing the Cabo Verde Islands the system was not expected to pose a direct threat to land for at least several days.
Isaac is expected to gain strength in the next day or two before beginning to weaken mid-week when it approaches the Lesser Antilles.