So far, the life-threatening storm has forced more than 26,000 people into emergency shelters and more than 1,100 flights along the US East Coast have been cancelled this weekend.
Hurricane-force winds now extend up to 80 miles and tropical-storm-force winds extend up to 195 miles from the center of the storm. Its surge could cover all but a sliver of the Carolina coast under as much as 11 feet (3.4 meters) of ocean water, and days of downpours could unload more than 3 feet (0.9 meters) of rain, touching off severe flooding.
"I ask all Georgians to join me in praying for the safety of our people and all those in the path of Hurricane Florence", Mr Deal said.
Hurricane Florence continues to drop category, but not unsafe, while hundreds of thousands of people try to get away from the coasts of the two Carolinas and Virginia.
Hundreds of residents were trapped in cars, on roofs and in their attics in North Carolina city of New Bern, which was flooded by the Neuse River.
Duke Energy Co. said Florence could knock out electricity to three-quarters of its 4 million customers in the Carolinas, and outages could last for weeks.
About 10 million people could be affected by the storm and more than 1 million were ordered to evacuate the coasts of the Carolinas and Virginia. Workers are being brought in from the Midwest and Florida to help in the storm's aftermath.
The shift in the projected track spread concern to areas that once thought they were relatively safe. "Now it might be time for the exam", he said.
A tree fell on a homeowner's auto, parked in the driveway as Hurricane Florence made landfall in Wilmington, North Carolina.
Unsure of what they might find when they return home, the couple went shopping for a recreational vehicle.
"I'm not going to put our personnel in harm's way, especially for people that we've already told to evacuate", Wrightsville Beach police chief Dan House said. "And since we have three dogs and three parrots, they're requesting us to take two to six rooms".
"It looks heavy outside", she said.
The National Hurricane Centre (NHC) said hurricane and storm surge warnings are in effect for South Santee River in SC to Duck, North Carolina, and the Albemarle and Pamlico sounds.
To hammer home the point, The Weather Channel created graphics showing just how risky storm surges can be, explaining how these turbulent waters can include detritus, chemicals and even electricity. It is expected that the hurricane moves on or near the coastline during the night of Thursday through Friday. Most other beachgoers were long gone. "You feel like you should have already left".