Florence is set to become a major hurricane very soon, according to the National Hurricane’s 5am AST (10am BST) weather advisory.
The hurricane is rapidly strengthening and should develop into a major Category 4 on Monday.
The storm currently has wind speeds of almost 105 mph (165 km/h).
The centre of Florence is expected to move over the southwestern Atlantic Ocean between Bermuda and the Bahamas tomorrow and Wednesday.
The southeastern coast of the United States will then be hit on Thursday.
Florence will remain an extremely dangerous hurricane until Thursday.
The NHC is warning people about swells caused by Florence which are affecting Bermuda and parts of the US East Coast.
The swells have been dubbed life-threatening. People in coastal areas should listen out for local weather forecasts.
AccuWeather Hurricane Expert Dan Kottlowski said that a landfall along the US East Coast is looking likely and the Carolinas at greatest risk late this week.
States of emergency have been issued in North Carolina, South Carolina and Virginia.
Mr Kottlowski said: “Residents and interests living along and near the Carolina coast and even up toward the Virginia Capes should closely monitor Florence and be ready to put their hurricane plan in place.
“If you do not have a hurricane plan in place, do so immediately.”
Florence became the first Category 4 hurricane of the 2018 Atlantic season last Wednesday.
However, it later weakened due to strong wind shear and cooler waters.
Since 1851, there have been at least 67 named storms to have passed within 200 nautical miles of where Florence has been travelling.
None of these storms have ever hit the US though, but Florence is different as it is being steered by an unusually strong area of high pressure over the north Atlantic Ocean.