It is projected to make landfall between Myrtle Beach, South Carolina, and Wrightsville Beach, North Carolina Thursday evening as a Category 4 Major Hurricane. Since reliable record-keeping began more than 150 years ago, North Carolina has only been hit by one Category 4 hurricane - Hazel, with 130mph winds, in 1954.
Virginia, and North and SC have declared states of emergency and authorities as far north as New Jersey are warning people along the coast to take precautions, including for the possibility of flooding rains far inland.
Florence "is particularly big, particularly strong and. there's nothing stopping it", the SC governor Henry McMaster said at a news conference on Monday.
Its center will move between Bermuda and the Bahamas on Tuesday and Wednesday and approach the coast of SC or North Carolina on Thursday.
The airlines affected by the waivers vary from city to city, but most are now in the path of Florence as meteorologists are tracking the category 4 storm.
Officials in North Carolina have already issued mandatory evacuation orders for coastal Dare County and Hatteras Island.
Tropical Storm Florence continues its churn toward USA coast
Additional strengthening is forecast for the next couple of days and Helene is expected to become a hurricane on Sunday. Most of the models are now showing Florence having a direct and major impact to the East Coast in the upcoming week.
The NHC also says the storm could become more powerful.
Meanwhile, Pentagon spokesman, Col. Robert Manning said, "Northern Command is spending an advanced team to the emergency operations center in Raleigh, North Carolina Monday to conduct an assessment and coordinate with federal and state partners".
Major US military installments may be in the path of the Florence, including the largest Marine base at Camp Lejeune in North Carolina and the world's biggest Navy base in Norfolk, Virginia.
At a Home Depot in Wilmington, North Carolina, Billy Nivens told CNN they ran out of water, plywood, generators, flashlights, propane, batteries and five-gallon gas cans by Monday afternoon. South Carolina Governor Henry McMaster has given the entire coastline until Tuesday noon to leave.
US President Donald Trump has cancelled a political rally planned for Friday in Jackson, Mississippi, over safety concerns related to Florence, his campaign said.
By 5 pm, the storm's winds had again increased to 140 miles per hour, with even stronger gusts.
North and SC are expected to be hardest hit on Thursday, with evacuations ordered by South Carolina's governor Henry McMaster. "Everyone in Virginia needs to prepare", he said. The designation gives officials the power to do order evacuations, establish shelters, prohibit travel and impose curfews.
A satellite image provided by the National Hurricane Center shows Hurricane Florence churning southeast of the Eastern Seaboard early on the morning of September 11, 2018. Accuweather added that storm swells are expected to stretch for hundreds of miles around Florence and impact, and there's a possibility that the storm could stall right as hits land, resulting in sustained battering of the coast and flooding.