The U.S. Coast Guard closed ports in Wilmington and Morehead City, North Carolina and Hampton Roads, Virginia to inbound vessels greater than 500 tons and was requiring vessels of that size to leave if they did not have permission to be in the ports. Home Depot and Lowe's activated emergency response centers to get generators, trash bags and bottled water to stores before and after the storm. The center said the waves were measured by satellite.
Emergency preparations in SC now include more than 2,100 of the state's National Guard soldiers.
In addition to strong winds, Florence brings the threat of a devastating storm surge - as high as 9 to 13 feet in the area from Cape Fear, N.C., to Cape Lookout, N.C.
The slow movement, combined with the massive amount of moisture this storm holds, will bring risky rains - from 20 to 30 inches in coastal North Carolina, with 40 inches possible in isolated areas, the weather service says.
And if that isn't enough, Subtropical Storm Joyce formed in the North Atlantic Tuesday afternoon, but it's not expected to hit the U.S. The system is expected to drift to the southwest in the coming days.
A buoy off the North Carolina coast recorded waves almost 30ft high as Florence churned toward shore.
A tropical storm watch is in effect for north of the North Carolina/Virginia border to Cape Charles Light, VA, and for Chesapeake Bay south of New Point Comfort.
The storm is now expected to make landfall in the lower Outer Banks of North Carolina early Friday morning or possibly stay in the ocean before making a shift to the left toward SC. "Florence is expected to produce total rainfall accumulations of 15 to 20 inches with isolated maxima to 30 inches near Florence's track over portions of North Carolina, Virginia and northern SC through Saturday".
Authorities in New Bern, a town of about 30,000 people that dates to the early 18th century, said more than 100 people had to be rescued from floods. With Hurricane Florence set to wallop the area as a Category 4 hurricane, there are fears the ponds could overflow or even collapse amid extremely heavy rain, sending vast amounts of manure from thousands of farms into rivers and contaminating groundwater.
Florence is predicted to turn more toward the northwest through Thursday - but then is expected to head more west-northwest and stall a bit over the Carolinas.
Hurricane-force winds were blowing 80 miles from its centre, and tropical storm force winds reached up to 195 miles from the eye. In South Carolina and inland parts of North Carolina, 5 to 10 inches of rain could fall, with 20 inches possible in some areas.
"The worst of the storm is not yet here but these are early warnings of the days to come", he said. Additional swell courtesy of other activity in the tropics keeps plenty of fun surf around for the weekend, so stay tuned to the regional forecast updates for the latest. "It goes well inland".
"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. You never know. But we know.