Cooper said local governments are typically responsible for issuing evacuation orders in North Carolina, and some localities have already issued orders to evacuate.
Donald Trump declared on Tuesday that his government is "absolutely, totally prepared" for Hurricane Florence, even as officials and forecasters warned that the "staggering" storm is shaping up to be catastrophic and unprecedented. It remains an extremely risky major hurricane through Thursday night. Watches were in effect Tuesday for a storm surge that could reach up to 12 feet at high tide on a stretch from Cape Fear to Cape Lookout in North Carolina, forecasters said.
For many people, the challenge could be finding a safe refuge: If Florence slows to a crawl, it could bring torrential rains into the Appalachian mountains, causing flash floods and mudslides across a region getting lots of rain recently.
This should only amplify rainfall totals as the storm's core remains offshore, with access to warm Atlantic waters to regenerate rain-making bands of precipitation.
With winds now at 140 miles per hour (225 km per hour), the storm was a Category 4 on the five-step Saffir-Simpson scale and expected to get bigger and stronger, the NHC said.
He said that North Carolinians should obey evacuation orders, as Florence is expected to affect millions in both North and SC. Hurricane Florence is expected to make landfall in the Tar Heel State on Friday.
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Communities in Florence's path could lose electricity for weeks due to downed power lines and flooded equipment, Federal Emergency Management Agency (FEMA) Administrator Brock Long said.
Hurricane Florence is now expected to head more directly west after making landfall, crossing through SC.
The Category 4 storm is located 905 miles (1456 km) east of Cape Fear, North Carolina and has maximum wind speeds of 130 mph (209 km/h), according to the National Hurricane Center. The stronger the storm, the stronger the winds and the higher the storm surge will be.
From the Ocracoke Inlet to the North Carolina-Virginia border and from the South Santee River to North Myrtle Beach, the NHC forecast that water could rise as high as 6 feet. Up to 35 inches of rain could fall through early next week over parts of the Carolinas and Mid-Atlantic states. "A similar set-up happened with Hurricane Harvey in the Houston area previous year, causing Harvey to move very little for about two days".
"It's what you expect if you have a shift toward more intense storms, is that you'll start seeing intensities you haven't seen before", said Gabriel Vecchi, an atmospheric scientist at Princeton who was one of the study's authors.
Trump said: "We are sparing no expense".
It likely goes without saying that hurricanes produce punishing, potentially deadly winds.
Half a dozen nuclear power plants, pits holding coal-ash and numerous hog farms are on the storm's path.
The category four hurricane is set to bring with it heavy rains and winds of up to 225 kilometres per hour.
"We've seen nor'easters and we've seen hurricanes before", Cooper said, "but this one is different".