"But it's possible the eye of Hurricane Florence will take a slight right turn to the south on Friday as it makes its way over eastern North Carolina, which could send a lot more rain to the Charleston area, according to Neil Dixon of the National Weather Service in Charleston".
"I ask all Georgians to join me in praying for the safety of our people and all those in the path of Hurricane Florence", Deal said.
A hurricane warning - meaning hurricane conditions are expected within 36 hours - is in effect for a long stretch of the coast, from the Santee River in SC to Duck, N.C., which is part of the Outer Banks.
Water kills more people in hurricanes than wind, and the rain and storm surge will make Florence extremely unsafe. Then it is likely to hover along the coast on Saturday, pushing up to 13ft of storm surge. "Today's the day", he said.
The time to prepare is nearly over, he said.
The National Hurricane Center said the hurricane's peak winds have decreased slightly to 125 mph but the size of the wind field has increased to outwards of 70 miles from the center. Its hurricane-force winds extend up to 60 miles from the storm's center.
At 11 a.m., Hurricane Florence was located about 485 miles southeast of Wilmington, North Carolina and about 520 miles east-southeast of Myrtle Beach, South Carolina.
Hurricane Helene is moving north, where it's expected to become a tropical storm on Thursday. It's now predicted to make landfall somewhere north of Wilmington, N.C., before its center heads inland toward the cities of Raleigh and Durham.
President Donald Trump declared states of emergency for North and SC, opening the way for federal aid. Officials are urging residents in coastal and low-lying areas to prepare for strong winds, a deep storm surge and a very prolonged deluge of rainfall.
"We've seen nor'easters and we've seen hurricanes before", Mr Cooper said, "but this one is different". "People are doing a pretty good job now". "I would say everybody should get out".
He said there was "well over $20 billion" in FEMA's disaster relief fund. Florence is now heading for ocean water with surface temperatures of around 85 degrees, meaning it will likely strengthen on its way to the East Coast. After its initial impact, Byard said the most serious concern will be massive rainfalls that would produce risky inland flooding.
Rain measured in feet is "looking likely", he said. "So Florence is kind of spreading out, becoming a much larger, more stable hurricane".
LATER NEXT WEEK: The remnants of Hurricane Florence could bring some heavy rain to the D.C. region by next week.
"Just because we have a landfall to your south, that doesn't mean you're out of the woods, because the winds are huge around this system", NHC Director Ken Graham said, pointing out the wide risk of flooding.
The hurricane watch notice is significant because it signals the opening of a 48-hour window for the expected first arrival of tropical storm-force winds.
More than 80,000 people were already without power as the storm began buffeting the coast, and more than 12,000 were in shelters.
On Tuesday afternoon, data from an Air Force Reserve hurricane hunter aircraft showed that Florence's sustained winds had picked up in speed again, hovering close to 140 miles per hour.
That's why the North Carolina IT Department is syncing its Raleigh data center with a second facility in Forest City, in the western part of the state, said Maggie Bizzell, an agency spokeswoman.
"It brings multiple threats, including a massive storm surge at the coast, as well as a potentially catastrophic inland flood situation".
ABOVE VIDEO: A high definition camera outside the International Space Station captured a stark and sobering view of Hurricane Florence at 7:50 a.m. EDT on September 12. North Carolina corrections officials said more than 3,000 people were relocated from adult prisons and juvenile centres in the path of Florence, and more than 300 county prisoners were transferred to state facilities. "This rainfall may produce life-threatening flash flooding".
"Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls".
A tree crashed into Kevin DiLoreto's home in Wilmington, where all roads leading to his neighbourhood were blocked by fallen trees. Power outages will last weeks to possibly months.
He added: "The waves and the wind this storm may bring is nothing like you've ever seen".