"It can not be emphasized enough that the most serious hazard associated with slow-moving Florence is extremely heavy rainfall, which will cause disastrous flooding that will be spreading inland through the weekend", the National Hurricane Center said in its 5 a.m. update.
Hurricane Florence began lashing the North Carolina coast on Thursday, with heavy surf pounding the Outer Banks and barrier islands, winds shredding flags, and a storm surge pushing seawater over some beaches and past oceanfront homes. Roof shingles were peeled off a hotel. As the storm moves inland it will find a relatively flat area for hundreds of miles.
Reports said coastal streets in North Carolina were flooded and winds bent trees to the ground as the storm, which has been downgraded to Category 1 and is weakened and slower moving than in recent days, prepared to make landfall at some point on Friday. When and where it will make landfall is unclear.
"On the forecast track, the center of Florence will approach the coasts of North and SC later tonight, then move near or over the coast of southern North Carolina and northeastern SC in the hurricane warning area on Friday", the briefing said.
In a display of the early effects of the storm, one flood gauge on the Neuse River in New Bern, North Carolina, showed 10 feet (three meters) of flooding, the NHC said.
The first tropical storm-force winds were forecast to hit the coast on Thursday.
Hurricane Florence already inundated coastal streets with ocean water and left tens of thousands without power early Friday, and forecasters say conditions will only worsen as the hulking storm slogs inland.
As Florence closed in, some residents weighed whether to ride it out.
The forecaster initially said he would stay in the newsroom to keep viewers up to date, but less than 20 minutes later he was forced to get out of the building.
In Wilmington, Richard King, 64, said Wednesday that he, his wife and perhaps 60 of their neighbors planned to stay.
"Florence is still a risky storm", said Rebecca Fuller, a meteorologist with Radiant Solutions in Gaithersburg, Maryland.
Footage from US TV outlets showed raging waters hitting piers and jettys, and rushing across coastal roads in seaside communities.
'We're going to take you now to the coverage from our sister station in Myrtle Beach'. Your time is running out.
FlightAware doesn't anticipate closures at any East Coast hubs (Charlotte, Atlanta or any Washington-area airports), limiting "cascading disruption to the rest of the nation's airport system", Orsi said in a statement Thursday. She packed up what she could and took a ferry Tuesday night.
"On a scale of one to 10, I'm probably a seven in terms of worry, she said".
There was also concern over crops.
Winds and rain were arriving later in SC, and a few people were still walking on the sand at Myrtle Beach while North Carolina was getting pounded.
Officials said traffic was moving well Wednesday though there have been two minor accidents in lanes where cars were traveling in the opposite direction from normal. On Thursday morning, South 17th Street, usually teeming with commuter traffic by 6:30 a.m., was almost devoid of cars.
The Federal Emergency Management Agency warned that storm surge watches and warnings are in effect Wednesday for the entire North Carolina coast and parts of SC.
New Bern, a city of about 30,000 residents, has been under a mandatory evacuation order since Tuesday.