The NHC said Florence is expected to be an "extremely risky major hurricane" when it makes landfall in the Carolinas late Thursday or early Friday, bringing life-threatening storm surge to coastal areas.
Like Hurricane Harvey in 2017, Florence is expected to slow significantly when it reaches the coast, allowing the storm to dump a catastrophic amount of rain in the Carolinas.
Duke Energy, the second-largest energy company in the United States, said Florence could knock out electricity to three-quarters of its four million customers in the Carolinas. "We're trying to get those last stragglers off of the barrier islands".
Florence is the most unsafe of three tropical systems in the Atlantic.
"And that's saying a lot given the impacts we've seen from Hurricanes Diana, Hugo, Fran, Bonnie, Floyd, and Matthew", the organization said in a statement that was circulated on Twitter.
"It's going to coming 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.
Florence will likely raise further questions over the role of climate change, given the increase in fierce, prolonged Atlantic hurricanes in recent years.
"I've been through hurricanes before but never with kids", she said.More news: Alibaba’s co-founder Jack Ma to retire next week, say reports
Tropical storm force winds are thought to be just hours away from making landfall in North Carolina. Because the storm was so strong earlier in the week, it built up a wall of water which will push inland as the storm surge.
Florence became a risky Category 3 hurricane Wednesday afternoon before it downgraded to a Category 2 Wednesday night with winds at 110mph.
Shepard Smith and Flaherty said reports showed storm surge from the system is likely to be felt dozens of miles inland, including along the Neuse River Basin - which stretches inward from New Bern toward Rocky Mount and Nashville, N.C.
The storm's winds may have weakened in recent days - they are now at 110mph (175km/h) - but there are fears Florence's slow-moving nature could bring different problems. For public safety, our live streams will be available to all residents of North Carolina.
In addition to tens of thousands of homes and businesses, five military bases and half a dozen nuclear power plants are also in the path of the storm.
The entire coastlines of North and SC, in addition to some parts of southeastern Virginia, are under a mandatory evacuation plan.
But the biggest danger could be life-threatening storm surges. Its wind speeds have dropped from a high of 140 miles per hour (225 kph) to 110 miles per hour (175 kph), reducing it from a Category 4 storm to a Category 2, and additional fluctuations and weakening were likely as it swirled toward land.
Many people in coastal communities have followed the mandatory evacuation orders, but some are vowing to stay put and ride it out. "You're going to be displaced from your home in coastal areas".