The U.S. Coast Guard closed ports in Wilmington and Morehead City, North Carolina and Hampton Roads, Virginia to inbound vessels greater than 500 tons and was requiring vessels of that size to leave if they did not have permission to be in the ports.
Officials in at least one area that ordered an evacuation will be going to homes to ask people planning to ride it out for information on their next of kin, CNN reported Wednesday.
By late Thursday into Friday, steering patterns in the atmosphere may completely break down causing the storm to stall just off the coast of southeast North Carolina and northeast SC.
Florence is moving over the southwestern Atlantic Ocean between Bermuda and the Bahamas today, and is expected to approach the coast of North Carolina or SC in the hurricane warning area on Friday.
Still, high winds will potentially inflict severe or complete damage to buildings, snap tree limbs or even uproot them, and knock power and water lines out.
Authorities, including President Trump and the Federal Emergency Management Agency (FEMA), are urging residents in the Carolinas as well as parts of Virginia and Georgia to evacuate as the storm continues its path.
Weekend sporting events have already been canceled, with possibly more to come.
In Charleston, South Carolina, streets were quiet with schools and many offices and businesses closed.
How much rain with North Carolina and SC receive?
A hurricane watch is in effect for Edisto Beach, SC, to South Santee River, SC.
Across southeastern North Carolina, north of Cape Fear, Florence could hit so hard that entire areas "may become uninhabitable for an extended period", the center stated.
Florence is so wide that a life-threatening storm surge was being pushed 300 miles ahead of its eye, and so wet that a swath from SC to OH and Pennsylvania could get deluged.
Evacuation orders for low-lying areas were issued Monday and continued Tuesday. Potential threats from hurricanes include powerful winds, heavy rainfall, storm surges, coastal and inland flooding, rip currents, tornadoes, and landslides. It may move a little north into Virginia or a little south into SC.
The impact of storm surge on the coast will depend on whether the storm's arrival coincides with high tide.
The NHS said coastal North Carolina could receive as much as 40 inches of rain in some areas, with storm surges between 9 and 13 feet.
As of 2 p.m. Wednesday, the Category 4 storm was about 435 miles southeast of Wilmington, N.C., and moving northwest at about 16 mph.