The hurricane center's projected track Wednesday had Florence hovering off the southern North Carolina coast from Thursday night until landfall Saturday morning or so, about a day later than previously expected.
Byard, the FEMA official, said "this storm is not going to be a glancing blow".
North Carolina Governor Ray Cooper said yesterday: "This storm is a monster".
So far, more than one million people along the coasts of North and SC and southern Virginia have fled. More to come on this part of the forecast. The stronger the storm, the stronger the winds and the higher the storm surge will be.
"This one really scares me", National Hurricane Centre director Ken Graham said.
Hurricane Florence is still a few days out from making landfall, and as we've seen, the forecast tract has varied. "But no matter how bad it's going to be, it will pass and our job will be to rebuild this community together, and that's what we're going to do". "So this is not just going to be a coastal threat". He underlined the point that even if you call 911, there is a chance rescue services may not be able to get to you.
In a videotaped message from the White House, President Donald Trump said the government was fully prepared for Florence but urged people to "get out of its way".More news: Henry Cavill is reportedly no longer playing Superman in the DC movies
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Forecasters do not expect that strength to change much before it makes landfall late Thursday or early Friday near the North Carolina-South Carolina border.
And in the 29 years since Hurricane Hugo struck, the population of the coastal Carolinas has skyrocketed.
"You have a degree of power to introduce certainty into this situation by heeding the governor's evacuation order", he said.
"The focus should be on the potential for torrential downpours that will lead to potentially life-threatening flooding", said meteorologist Scott Sharp.
Other major carriers in the United States, including Delta Air Lines, Southwest Airlines and United Airlines, have similar travel advisories in place, with Southwest even issuing waivers for travelers using airports as far north as Baltimore and Washington D.C.
Some areas could get deluged with 20 inches of rain, Myers said.
The longer the storm stalls near the coast, the more precipitation it will be able to pull from the Atlantic and dump inland.
"A lot of our storefronts are boarded up", said Lynn Davis, town manager for Belhaven which sits at sea level in northeastern North Carolina. A tropical storm watch was also in effect for parts of Virginia.