Eventually, Florence will veer north into the Appalachian Mountains, bringing soaking rains to Virginia and western North Carolina, before sputtering out late next week near DE and Maryland, the FWS reported.
South Carolina Governor Henry McMaster ordered as many as one million residents of the state's eastern coast to leave their homes ahead of the storm's predicted arrival today.
The first tropical storm-force winds of at least 39 miles per hour (63 kph) were forecast to hit the coast on Thursday.
A state of emergency has been declared in 5 states including North and SC, as well as the capital, Washington D.C.
Dangerous Hurricane Florence edged closer Thursday to delivering a powerful blow to the east coast of the United States, with forecasters warning of life-threatening rainfall and flooding even as it weakened to a Category 2 storm.
According to the National Hurricane Center, the eye of the hurricane will likely not blow ashore until Friday afternoon local time, after which it will then push westward and bring with it the potential for catastrophic inland flooding. Tropical-storm force winds extend outward to 105 miles from the center.
While a small craft warning and a high surf advisory will be in effect for Barbados from 6 p.m. tomorrow until further notice, no storm watch or warning has been issued, at least for now.
Areas along the coast from Cape Fear to Cape Lookout, NC, including the Neuse, Pamlico, Pungo and Bay rivers may experience storm surges from 9 to 13 feet.
"The deepest water will occur along the immediate coast in areas of onshore winds, where the surge will be accompanied by large and destructive waves", the NWS report said.
Barbados is expected to start feeling the impact of tropical storm Isaac between late tonight and early morning.
Georgia Governor Nathan Deal declared a state of emergency "in light of the storm's forecasted southward track after making landfall". Authorities in Chatham County, Georgia, which borders SC and includes the historic port city of Savannah, urged residents who feel unsafe "to evacuate as they see fit".
On the forecast track, Isaac's centre is forecast to move across the central Lesser Antilles and into the Eastern Caribbean Sea on Thursday and into the central Caribbean Sea on Saturday. Puerto Rico and the Virgin Islands face possible isolated amounts of 3 inches.
Hurricane and tropical storm watches have been posted for several Caribbean islands as a weakening Tropical Storm Isaac continues its trek toward the Leeward and Windward Islands. It is expected to turn away from the U.S.
Isaac is now a Tropical Depression, as a Hurricane hunter heads to investigate the system.
Interestingly, the Atlantic Ocean housed three hurricanes at the same time, that before Tropical Storm Isaac being downgraded from its former hurricane status.