"This will likely be the storm of a lifetime for portions of the Carolina coast", the National Weather Service in Wilmington, North Carolina, wrote in its Tuesday evening area forecast discussion, adding in a Wednesday report that flooding in southeast North Carolina and northeast SC could be "unprecedented".
About 10 million people could be affected by the storm and more than 1 million were ordered to evacuate the coasts of the Carolinas and Virginia, jamming westbound roads and highways for miles.
Wilmington, North Carolina, just north of where the hurricane is expected to come ashore, was sunny around midday on Wednesday as the town appeared to be emptying.
Commenting on the threat, Governor Cooper said: "North Carolina, my message is clear: Disaster is at the doorstep, and it's coming in".
Mr Trump was later briefed in the Oval Office in front of TV cameras by Brock Long, head of the Federal Emergency Management Agency (Fema). "Because it's Mother Nature".
Homeless after losing her job at Walmart three months ago, 25-year-old Brittany Jones went to a storm shelter at a high school near Raleigh.
"I've been through hurricanes before but never with kids", she said.
"It doesn't matter how much money you have or how many generators you have if you can't get gas", she said.
'The waves and the wind this storm may bring is nothing like you've ever seen.
Pompeo slams Kerry for 'inappropriate' meetings with Iran officials
On the day former Trump campaign chair Paul Manafort agreed to cooperate with the special counsel, Kerry also got in a Manafort-Mueller jab.
Duke Energy, a power company in the Carolinas, estimated that one million to three million customers could lose electricity because of the storm and that it could take weeks to restore.
As of 11 p.m., the storm was centered 280 miles east southeast of Wilmington, N.C., and was moving northwest at 17 mph, and this general motion, accompanied by a gradual decrease in forward speed, was expected to continue through Thursday. Workers are being brought in from the Midwest and Florida to help in the storm's aftermath, it said.
Winds are now expected at slightly less extreme levels, around the 120 miles-per-hour level associated with a Category 3 storm.
Scientists said it is too soon to say what role, if any, global warming played in the storm.
The relationship between climate change and hurricanes is a complex one.
A National Weather Service forecaster said: "This will likely be the storm of a lifetime for portions of the Carolina coast".
Frustrated after evacuating his beach home for a storm that was later downgraded, retired nurse Frederick Fisher grumbled in the lobby of a Wilmington hotel several miles inland. "It wants to get stronger", he said of the storm.
- Governor Roy Cooper (@NC_Governor) September 12, 2018If you are under an evacuation order and you haven't left yet, the time to leave is now. But authorities warned Florence has an enormous wind field that has been growing larger, raising the risk of the ocean surging on to land and making Florence extremely risky.
"I was born here", he told me today.