"Florence is forecast to rapidly strengthen to a major hurricane by Monday, and is expected to remain an extremely unsafe major hurricane through Thursday", the NHC said in an advisory issued at 9:00 pm (local time) Sunday.
NASA is using its various high-flying tools to monitor the storm, taking precipitations measurements and NOAA's National Hurricane Center is using that data to forecast the storm's progress.
Florence is now moving west at around 13 miles per hour (20 kph), and is forecast to drench a large swath of the US East Coast running from northern Florida to New Jersey.
Though no coastal advisories are yet in place, the update said that those warnings would likely be forthcoming.
A surge in the waters off the New England coast is expected to begin as soon as tomorrow, and could lead to some especially high tides and risky rip currents, Simpson says, but that's about it.
All eyes are on Hurricane Florence and its path toward the Carolinas, but several other hurricanes are brewing as well. Large swells could be generated and cause damage in some parts of the state, which survived brushes with hurricanes Hector and Lane in recent weeks.
The National Hurricane Center's next update on Hurricane Florence is scheduled for 11 p.m.
The hurricane center noted that, when it comes to predicting the path of a hurricane four and five days in the future, it can be off by an average of about 140 and 180 nautical miles. Since reliable record-keeping began more than 150 years ago, North Carolina has only been hit by one Category 4 hurricane: Hazel, with 210 km/h winds in 1954.
"A hurricane is coming our way". A turn toward the northwest is forecast to occur on the night of September 12, the NHC said.
Hurricane Florence is growing in size and strength as it barrels toward the Southeastern U.S. for an expected landfall in the Carolinas later this week as an "extremely risky hurricane", according to the National Hurricane Center.
Florence is expected to strengthen further.
Preparations for Florence come as the Atlantic hurricane season hits its peak.
A rip current statement is in effect for all beaches in Brunswick, New Hanover and Pender counties.
The National Weather Service has also forecasted heavy swells from Surf City north along the coast.
Hurricane Florence is now a Category 2 storm and is still forecast to slam into the southeastern United States.
Sustained winds on Tuesday afternoon approached 105 miles per hour, making it a very strong Category 2 storm, though it was expected to gradually weaken over cooler waters.
Given the potential impact, officials say now is the time to get supplies and a way to receive weather alerts.
"It's nearly certain there will be some impact on Charlotte, but it depends on the track", meteorologist Jake Wimberley said from the weather service's office in Greer, S.C. The office forecasts for the western Carolinas including Charlotte. It was centered about 1,230 miles (1,985 kilometers) east-southeast of Cape Fear, North Carolina, and moving west at 13 mph (20 kph).