Don't be fooled by the fact that Florence has weakened slightly to a Category 2 hurricane; categories only denote the speed of sustained winds.
Winds were already picking up along the coastline on Thursday morning and Myrtle Beach was virtually deserted with empty streets, boarded up storefronts and very little traffic.
"You're going to have damaging winds for a longer period of time", senior hurricane specialist Stacy Stewart said in an update from the NHC. "Because I don't know that we can go in and get you".
As of 5 a.m. EDT (0900g) it was centered about 205 miles (325 kilometers) east-southeast of Wilmington, North Carolina and about 250 miles (450 kilometers) east-southeast of Myrtle Beach, South Carolina, moving northwest at 15 mph (24 kph).
Duke Energy, the nation's No. 2 power company, said Florence could knock out electricity to three-quarters of its 4 million customers in the Carolinas, and outages could last for weeks.
"Sometime on Friday afternoon, Friday evening or Saturday morning", Goldstein said. Hurricane-force winds extend out for 80 miles and the tropical-storm-force winds reach 195 miles out from the center.
More than 10 million people are under a storm watch or warning in Virginia and the Carolinas, where up to 40 inches of rain could fall.
Despite the weakening, the effects would still be devastating in North Carolina.
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Officials say people refusing to evacuate could end up alone, drenched and in the dark, as rescue crews won't go out to help in winds above 50 miles per hour.
Previously classified as a Category 4 on the five-step Saffir-Simpson scale of hurricane strength, Florence is so far the most severe storm to threaten the U.S. mainland this year and the first of its magnitude to target the Carolinas since 1989 when Hurricane Hugo barreled over Charleston, South Carolina.
In Shallotte, N.C., a coastal town near the border with SC, emergency orders forced a Waffle House to shut down - an act that was widely seen as a sign of respect for Florence's imposing size and strength.
In Virginia, 245 000 coastal residents were ordered to evacuate.
The assistance also includes Florida utilities sending crews to help restore power after the hurricane and the state suspending requirements for transportation of animals to help in the movement of livestock from areas affected by the hurricane. Cooper said over 100 shelters are open in North Carolina with 7,000 evacuees taking refuge from the powerful storm.
North Carolina Gov. Roy Cooper urged residents to remain alert despite changing forecasts. But forecasters warned that the widening storm - and its likelihood of lingering around the coast day after day - will bring seawater surging onto land and torrential downpours. "In light of the storm's forecasted southward track after making landfall, I encourage Georgians to be prepared for the inland effects of the storm as well as the ensuing storm surge in coastal areas".
Not everybody was heeding orders to evacuate, however.
"The shelters are not taking dogs", Ramirez said.
"But I'm not afraid", he said. "There is overwash but nothing we are not used to", she said.