The hurricane was gaining strength as it traveled over warm Atlantic waters, about 1,240 miles (2,000 km) east-southwest of Cape Fear, North Carolina, the National Hurricane Center said in an advisory.
The northern coast of SC and the Outer Banks of North Carolina are likely to be the areas most impacted by the storm, which could cause $15.32 billion in damage if it stays on its current five-day forecast track, said Chuck Watson, a disaster researcher at Enki Research in Savannah, Georgia.
There are no coastal watches or warnings in effect at this time, but Met Service said strengthening is forecast during the next few days and Isaac is expected to become a hurricane by Monday.
WILMINGTON, North Carolina (CNN) - More than 1 million people on the southern East Coast of the United States faced mandatory evacuation orders as Hurricane Florence neared Category 5 strength Tuesday.
National Hurricane Center Director Ken Graham warned that Florence was forecast to slow down significantly and linger over the Carolinas once it reaches shore, dropping heavy rainfall as far as West Virginia.
On the forecast track, the center of Florence will move over the southwestern Atlantic Ocean between Bermuda and the Bahamas Tuesday and Wednesday, and approach the southeastern U.S. coast on Thursday.
Hurricane Florence appears to be taking aim at the largest U.S. Marine Corps base on the East Coast. Storm surge and freshwater flooding from rainfall could become life-threatening risks, especially from SC through the mid-Atlantic.
Hurricane Florence had maximum sustained winds of 90 mph as of 11 p.m. Sunday, and is 685 miles southeast of Bermuda, moving west at 7 mph. It was expected to strengthen into a hurricane then weaken by the middle of the week. Regardless of where Florence comes near land, its impact, including wind, rain, and storm surge, will be felt well outside the immediate area near storm's center. "I am declaring a state of emergency so that we can begin to prepare state assets, and I encourage Virginians to monitor forecasts and make their own preparations now", Northam said.
USGS Is Installing About 160 Sensors Along NC, SC Coasts For Florence
Emergency officials say they're keeping a close eye on the forecast and where to move resources to respond to the storm. On Sunday, Florence reached sustained winds of at least 74 miles per hour to be classified a hurricane.
The late Monday night update shows the model tracks shifting slightly north up North Carolina where it's expected to take aim at the southeastern coast. A Category 4 storm packs winds of 209 km/h or more and has the potential for catastrophic damage.
As of the NHC's advisory issued at 11 a.m. EST Sunday, Hurricane Florence's center will move over the Atlantic Ocean between Bermuda and the Bahamas on Tuesday and Wednesday, and it will get to the southeastern US coast on Thursday.
Still, it remains unclear where Florence will make landfall, and, therefore, which areas will feel the worst impact.
"There is an increasing risk of life-threatening impacts from Florence", the hurricane center has been saying for days.
"North Carolina is no stranger to hurricanes", Cooper said at a press briefing, noting that previous hurricanes - Matthew in 2016, Floyd in 1999 and Fran in 1996 - brought heavy wind and rain to the entire state.
Florence is moving toward the west-northwest near 15 miles per hour. Major hurricanes have winds of at least 111 miles per hour (179 kph). "The last Atlantic hurricane to intensify as rapidly as far north as Florence's current location was Hurricane Humberto in 2007", he said.
Graham urged coastal residents to finish their planning before the arrival of tropical-storm-force windows on Wednesday.
The storm's first effects were already apparent on barrier islands as risky rip currents hit beaches and seawater flowed over a state highway. Florence could grow into a Category 4, with sustained winds of at least 130 miles per hour as it crosses over the warm Atlantic waters.