Hurricane Florence strengthened early on Monday, packing maximum sustained winds of 105 miles per hour (170 kph), and forecasters warned that it is "expected to become a major hurricane very soon" as it churns toward the U.S. East Coast.
Should it strike in the Carolinas and Virginia, Florence could potentially cause $15 billion in damage, which would put it among the 12 costliest to hit the US, said Chuck Watson, a disaster modeler with Enki Research in Savannah, Georgia. It will continue to strengthen and likely upgrade to a category 4 by Tuesday. Eight hundred members of the National Guard have been activated in the state.
In a press conference Sunday, McMaster said he had submitted a request to President Trump that a federal emergency declaration be made.
Dare County officials have announced that a mandatory evacuation order goes into effect on Hatteras Island at noon Monday.
Governors in Virginia, North Carolina and SC have all declared states of emergency over the past two days in anticipation of the storm.
The state's Division of Marine Fisheries is also calling on fishermen to start preparing and should remove fishing gear from the water well before the storm arrives. Vessel owners should make sure to check safety equipment is working and remove boats from the water or take them to safe harbor as the storm approaches.
The storm's winds grew by 35 miles-per-hour in the last 24 hours, and Florence is forecast to reach Category 4 status, one step short of the the most severe level, with 150 mile-per-hour winds by Wednesday.
Its center will move between Bermuda and the Bahamas Tuesday and Wednesday, and approach the coast of SC or North Carolina on Thursday, the National Hurricane Center said.
Hurricane Florence seen over the Atlantic Ocean, about 750 miles southeast of Bermuda in this handout photo provided by the National Oceanic and Atmospheric Administration on September 9, 2018.
Hurricane track and intensity forecasts often have wide margins of error beyond five days, and with Florence computer models have struggled to accurately predict what the storm will do. That storm was centred 185 km south southeast of the islands. "We've already had multiple very intense hurricanes out in the central pacific by Hawaii", he says. However it's still expected to be at or near hurricane strength by the time it reaches the Lesser Antilles.
Hurricanes Helene and Isaac are not expected to hit the U.S. mainland.
North Carolina officials on Monday ordered residents to evacuate the state's Outer Banks barrier islands beginning on Monday ahead of Hurricane Florence, the first major hurricane to threaten the eastern United States this year. The flooding might be similar to what the Carolinas experienced during Hurricane Matthew in 2016. "This is a serious storm and it's going to affect the entire state of Virginia". Yesterday, data pointed to a landfall smack dab in the middle of the Palmetto coastline between Charleston and Myrtle Beach - near where category three monster Hurricane Hugo, roared ashore back in 1989.
The first effects of what forecasters are already calling a large and extremely risky hurricane were already being seen on barrier islands Monday as unsafe rip currents and seawater flowed over the state highway.
"This storm is too powerful and its path is too uncertain to take any chances", McMaster said.
According to the National Hurricane Center, this general motion with an increase in forward speed is expected during the next couple of days.
Virginia Governor Ralph Northam's office described Florence as possibly the state's "most significant hurricane event in decades", and warned of "catastrophic inland flooding, high winds and possible widespread power outages".
Large swells generated by Florence are already affecting Bermuda and portions of the East Coast and will continue this week.