The National Hurricane Center's latest forecast calls for Florence to strike the coast near Wilmington early Friday and inch slowly west over Myrtle Beach, South Carolina, through early Saturday and then head northwest across South Carolina toward the northeast corner of Georgia by Monday morning.
It's a detail that almost got lost among all the wind, rain and storm surge data sent out by the National Hurricane Center on Wednesday.
Britain is bracing itself for strong winds and heavy rain as Hurricane Helene makes its way across the Atlantic.
The cone of possible tropical storm force wind now reaches 13 states, with all of Georgia, North Carolina, South Carolina and Virginia having a chance of receiving winds of 39 miles per hour or above. As the storm moves inland, Georgia, Virginia and Maryland will also be in peril.
The National Hurricane Center said in its 11 a.m. ET advisory that up to 5 inches of rain could fall in Puerto Rico. Isaac is forecast to gradually weaken over the next few days, and could degenerate into a tropical wave during that time. As of Wednesday afternoon, Helene had maximum sustained winds near 90 miles per hour.
As Florence nears the east coast, meteorologists are focused on two key factors: ocean temperatures and wind sheer (the difference in speeds at the upper and lower parts of the storm).
The National Hurricane Center is predicting the storm will produce "catastrophic flash flooding and significant river flooding".
It's unclear whether Isaac could reach the USA mainland. Current estimates have Isaac passing nearly 150 miles south of St. Croix early Friday morning.
Meteorologist's Reaction to Hurricane Florence: 'Wow'
Damaging winds, floods, high surf and storm surge are still possible. "Florence is a threat well beyond our coast", Cooper said. We encourage anyone in the path of these storms to prepare themselves and to heed the warnings of State and Local officials.
Tornadoes: Tornadoes will be possible along and to the right of the track of Florence, including the Midlands, Pee Dee and Catawba Regions, this is especially in SC.
Jeff Byard of the Federal Emergency Management Agency said it was imperative locals heed the evacuation warnings.
"As we enter the more active phase of the hurricane season residents should have their hurricane preparedness plans well established and in place, and be ready to complete final arrangements such as shuttering and moving to safe shelter if necessary".
Hurricane Florence isn't the only storm threatening lives and property around the world.
The storm is now around 530 miles southeast of Cape Fear, North Carolina, and is moving west-northwest at 17 mph.
President Donald Trump declared states of emergency for North and SC and Virginia, opening the way for federal aid.
Tropical storm warnings have been issued for Martinique, Dominica, and Guadeloupe. Florence, the most ominous for United States residents, is expected to make landfall today.