The NHC said the first tropical storm-force winds of at least 39 miles per hour (63 kph) would hit the region early on Thursday with the storm's center reaching the coast Friday. "There are approximately 800 line workers and tree personnel actively engaged in storm response preparations".
The storm's possible track now bends farther to the SW and closer to cities like Jacksonville, but it's the delay and the possible repeat of a Harvey-like storm cycle that has officials and weather forecasters anxious.
Hurricane Florence carries a heavy risk of flash floods as it brings up to 13-foot storm surge and a possible 40 inches of rain to the Carolina coast.
The center of Florence is expected to hit North Carolina's southern coast Friday, then drift southwest before moving inland on Saturday. This implies that water, even more so than wind, is the most risky element of a major storm.
"Hurricane Florence was uninvited but she's just about here anyway", North Carolina Governor Roy Cooper told a news conference, warning people not to be complacent just because the storm's winds had diminished.
The massive storm is larger than North Carolina and South Carolina - combined, according to South Carolina Emergency Management. The low-lying barrier islands hugging the Carolinas coast are experiencing some of the fastest rates of sea level rise in the world, almost an inch a year. And Florence is a large storm, with hurricane-force winds extending outward up to 80 miles from the center and tropical-storm-force winds outward up to 195 miles.
Hurricane warnings are in effect for the South Santee River in SC to Duck, North Carolina, and Albemarle and Pamlico sounds. This website is not intended for users located within the European Economic Area.
A tropical storm warning covers the area from north of Duck to the Virgina Tidewater area.
Florence is becoming more of a threat to more people - now including some in Georgia - in more ways.
"It's still going to be the same result with the amount of water that's being pushed on shore", he explained. People in the Carolinas had the daytime hours Thursday to complete their final preparations to ride out or escape the storm.
The center of Florence will approach the coasts of North and SC on Thursday, then move near or over the coast of southern North Carolina and eastern SC on Thursday night and Friday, the NHC added.
Masters said there's a tug-of-war between two clear-skies high-pressure systems - one off the coast and one over MI.
Storm surge is deadly.
"Floodwaters may enter numerous structures, and some may become uninhabitable or washed away", the Weather Service warned.
It's unclear exactly how many people evacuated, but more than 1.7 million people in the Carolinas and Virginia were warned to clear out. "I encourage Georgians to be prepared for the inland effects of the storm as well as the ensuing storm surge in coastal areas". The actual landfall - when the center of the eye reaches land - will be Friday afternoon at the earliest, said Neil Jacobs of the National Oceanic and Atmospheric Administration.
"Catastrophic damage will occur: A high percentage of framed homes will be destroyed, with total roof failure and wall collapse". Regardless of whether a system forms, they say heavy rain and gusty winds are likely along the Texas and Louisiana coast later this week.
By way of computer modeling, Duke Energy anticipates between 1 and 3 million customers in the Carolinas to lose power in addition to those Dominion serves in Virginia.
"The rain's going to be around for a long time", he said.
It's incredibly hard to pin down a storm's precise death toll because of the myriad, chaotic factors that accompany a natural disaster. Twenty-six people were killed in the U.S, and 14 of them in North Carolina.