Forecasters said conditions will deteriorate as the storm pushes ashore early Friday near the North Carolina-South Carolina line and makes its way slowly inland. As of Thursday afternoon the storm was generating sustained winds of 105mph, as storm surge water has begun to rush into homes and streets along beachside communities.
Florence is about 644 kilometres wide and it's winds have dropped from a peak of 225 km/h to 165 km/h, reducing the hurricane from a terrifying Category 4 to a Category 2.
A camera at the Frying Pan Tower located 34 miles off the coast of Cape Fear, North Carolina has been livestreaming a view of the Atlantic Ocean since May, and is powering through the storm to dutifully record an American flag over the rising waves.
General O'Shaughnessy said there were about 7,000 U.S. military personnel now in place and ready to respond to the storm, along with ships, helicopters, high-wheeled vehicles and other equipment.
Florence is now moving to the northwest at 17 kilometers per hour. "Remember that floods will occur in places that do not receive a hurricane or even tropical storm level winds".
The outer bands of the cyclone drenched the Carolinas on Thursday, flooding roads and knocking out power in an ominous glimpse of the damage it could inflict when it makes landfall on Friday. Forecasters are predicting as much as 40in of rain in some localized areas.
By early evening, almost 70,000 residents were without electricity, according to North Carolina Emergency Management. "Inland flooding kills a lot of people, unfortunately, and that's what we're about to see", he said.
The head of Duke Energy Corp.'s North Carolina operations says it could take weeks to restore electricity if the company's prediction that 1 million to 3 million of its 4 million customers lose power.
The NHC warned the threat of tornadoes was increasing as Florence neared shore and South Carolina Governor Henry McMaster said the heavy rains could trigger landslides in the western part of his state.
About 10 million people live in the path of the slow-moving storm and more than one million have been ordered to evacuate the coasts of the Carolinas and Virginia.
Some people, such as Jennie, are refusing to heed evacuation warnings.
Antonio Ramirez, a construction worker from El Salvador living in Leland, North Carolina, said he planned to ride out the worst of the weather with his dog Canelo. "Once you leave, you don't know how many days it will be before you can return", she said.
In Wilmington, residents who had decided not to evacuate were lining up to get ice from a vending machine - $2 for a 16-pound (7.2-kilo) bag.
"I have no generator", said Petra Langston, a nurse. "I learned from the past to keep the ice in the washing machine". "I should stay in my house, where I have water and food". "I charged the batteries of my electronic devices, I have beers and video games".