Hurricane and Storm Surge Watches have been issued for the east coast of the United States from Edisto Beach, South Carolina northward to the North Carolina-Virginia border, including the Pamlico and Albemarle Sounds.
The storm is now 905 miles east-southeast of Cape Fear, North Carolina, with landfall predicted between Charleston, South Carolina and Norfolk, Virginia. As of midday on Tuesday, Florence remains a powerful category 4 hurricane with maximum sustained winds of 130 miles per hour.
The storm will make landfall Friday in North Carolina, according to the latest forecasts. In anticipation of the storm, governors of North Carolina, South Carolina, Virginia, and Maryland have declared states of emergency.
Evacuations of coastal North Carolina began at noon Monday, with Dare County officials calling for the entire county to evacuate.
South Carolina Governor Henry McMaster evoked the memory of 1989's Hurricane Hugo, which killed 27 people in the state, in urging people to obey his evacuation order.
Coastal areas are likely to experience storm surges and the hurricane may dump heavy rains across the entire mid-Atlantic region, causing unsafe floods. Storm surge is also a major concern. In Virginia, almost a quarter-million people have been ordered to evacuate from the shore.
Florence's max sustained winds have been clocked at 130 miles per hour with an further increase expected on Monday.
The storm is expected to threaten the Carolinas and Virginia. That would mean more flooding rains across a large part of the U.S. South, expanding the damage, according to Chuck Watson, a disaster modeler with Enki Research in Savannah, Georgia.
Simpson said the coverage and attention on Florence is a reminder for New Englanders of the importance of being vigilant during hurricane season and preparing for severe weather "way before any potential event".
It's important to remember that hurricane forecasts for both track and intensity are still subject to change.
A big worry with Florence is that the system could linger for days, similar to the manner in whch Harvey hovered over Texas a year ago.
The exact timing, location and magnitude of the storm's impacts on the US southeast coast in not yet clear but forecast tracks show it could make landfall along the Carolinas and southeast Georgia. "But it's important to remember the impacts of this hurricane will extend far beyond where it makes landfall. This rainfall may produce life-threatening flash flooding".