Oddly, the closer Hurricane Florence gets to land the murkier its future gets.
The center of Florence will move over the southwestern Atlantic Ocean between Bermuda and the Bahamas Wednesday night, and approach the coast of North Carolina or SC in the hurricane warning area on Thursday and Friday, NHC said.
More than 1.7 million people were warned to evacuate and get out of the way of the "life-threatening" storm's path.
With South Carolina's beach towns more in the bull's-eye because of the shifting forecast, OH vacationers Chris and Nicole Roland put off their departure from North Myrtle Beach to get the maximum amount of time on the sand.
While Florence is no longer considered a major hurricane, its reach has expanded, threatening residents from Georgia to Virginia.
The enormous waves were recorded in the northeast quadrant of the hurricane, which is the strongest area of the storm.
A buoy off the North Carolina coast recorded waves almost 30 feet (9 meters) high as Florence churned toward shore.
Weather Underground meteorology director Jeff Masters said Florence eventually could strike as merely a Category 1 hurricane with winds less than 100 miles per hour (160 kph), but that's still enough to cause at least $1 billion in damage.
"For a meandering storm, the biggest concern - as we saw with Harvey - is the huge amount rainfall", said Chris Landsea, chief of tropical analysis and forecast branch at the National Hurricane Center.
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.
The Miami-based NHC stressed, however, that while a slow weakening is expected over the next 24 hours "Florence is still forecast to be an extremely risky major hurricane when it nears the United States coast late Thursday and Friday".
Governor Nathan Deal declared a state of emergency for the state of Georgia: "in light of the storm's forecasted southward track after making landfall".
"The state is mobilizing all available resources to ensure public safety", Deal said. But it could have been worse: Labor Day marked the end of the peak tourism season in the Outer Banks of North Carolina and other coastal getaways.
St. Helena Island near the South Carolina-Georgia line is used to riding out big storms - from one that killed an estimated 2,000 people in 1893 to Tropical Storm Irma a year ago.
As Florence closed in for the worst strike on the area in decades, President Donald Trump and state and local officials urged residents in the path of the storm to evacuate before it is too late.
And there's "a huge difference" in the size and type of damage Florence inflicts if it stays 50 miles (80 kilometers) off shore versus heading inland immediately, Landsea said. "Because it's Mother Nature". "I want to get them as far away as possible".
"I've been through hurricanes before but never with kids", she said. One North Carolina woman packed flowers to leave on her son's grave.
Hurricane force winds will emanate up to 70 miles from the centre of the storm, say meteorologists.
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