At 11:00 pm (0300 GMT), the eye of the storm was 280 miles (450 km) southeast of Wilmington, North Carolina, moving northwest at 17 mph.
If some of the computer projections hold, "it's going to come roaring up to the coast Thursday night and say, 'I'm not sure I really want to do this, and I'll just take a tour of the coast and decide where I want to go inland,"' said Jeff Masters, meteorology director of the private Weather Underground forecasting service.
More than 1.5 million people have been asked to evacuate their homes along the Virginia, North and SC coasts as Category 5 storm Hurricane Florence approaches, an official said. Forecasters also were tracking two other disturbances. Hurricane watches are in place around most of the SC coast, and tropical storm warnings were in effect in southern Virginia.
Beyond the Carolinas and Virginia, which were expected to bear the brunt of the storm, rain and flooding were expected through next week in certain parts of Tennessee, Georgia, West Virginia, Ohio, Pennsylvania, Maryland and the District of Columbia.
Her home in Hillsborough, North Carolina, is at risk for flooding, and her family and nearby relatives will ride out the storm in Chattanooga, Tennessee.
In Virginia, 245,000 coastal residents were ordered to evacuate, including from the Eastern Shore, another popular beachfront destination.
Should other states request storm-related assistance from the Georgia Emergency Management Agency, GEMA would in turn ask its Athens counterpart if the county could lend a hand by sending supplies or personnel to storm-ravaged areas.
The National Hurricane Center says Hurricane Florence is expected to bring life-threatening storm surge and rainfall to portions of the Carolinas and mid-Atlantic states.
Myrtle Beach also announced a curfew starting 10 p.m. starting Wednesday until 6 p.m. Thursday.
By Saturday, total rainfall could accumulate to 30 inches (76 centimeters) - or even 40 inches in places - in parts of the Carolinas and Virginia, the NHC said.
Residents on the Carolina coast are finding empty gas pumps and depleted store shelves as they flee a potentially devastating blow from Hurricane Florence.
South Carolina Governor Henry McMaster ordered the mandatory evacuation of one million coastal residents.