BOSTON (CBS) – Life-threatening. Catastrophic. Historic. It is hard to describe or even imagine what is about to unfold over parts of southeastern United States. Hurricane Florence has a bead on the Carolinas. There is no last minute turn out to sea. The forecast challenge now is trying to determine the small wobbles north or south because each little change has life-altering consequences for those along the Carolina coastline. A 50-mile jog one way or another, a stall in the forward movement, even the slightest shift in track will mean an escape for some communities and devastation for others.
Hurricane Florence: Tracking Maps and Computer Models
As of midday Wednesday, Florence remains a category 4, major hurricane. There has been very little change in the last 24 hours. The inner core of Florence, where the strongest winds are located, has expanded slightly measuring about 100 miles across.
Its forward speed remains steady, about 15 mph to the northwest. Florence is forecast to approach the SC/NC coastline early on Friday morning and then slow to a crawl, perhaps becoming nearly stationary just offshore.
COULD IT STRENGTHEN?
There is a window for some possible strengthening in the next 12-to-24 hours. Florence will be riding over some of the warmest ocean waters during this time (mid 80’s) and also will be in a corridor of very little wind shear.
Thereafter, as Florence slows its forward speed, significant ocean water upwelling will occur bringing cooler water to the surface. This is the one benefit of the hurricane slowing or stalling. As the water cools beneath Florence, some gradual weakening will begin as early as late Thursday night and early Friday.
This has been the biggest forecast challenge and remains a bit of an unknown. Instead of moving inland near Wilmington, North Carolina, it now appears that Florence will stall just offshore of Wilmington. Most models now show a slow drift to the south-southwest during Friday until finally making an official landfall in northern parts of South Carolina (possible near Myrtle Beach).
While the hurricane will likely weaken from a category 4 to a category 2 during this time, the slow progression and long duration of wind and rain will have devastating consequences along the coastline from Wilmington to Myrtle Beach.
From there, Florence will drift inland, through South Carolina over the weekend and slowly degrade from a minimal hurricane to a tropical storm and eventually just to a remnant low pressure area by late Sunday.
WIND AND SURGE
Sustained winds over 100 mph will push a life-threatening storm surge along the South and North Carolina coastline.
Many models are predicting a surge greater than 9 feet for a good portion of the area, washing up many of the waterways and inlets, devastating homes and businesses located along the shore.
Catastrophic river flooding and flash flooding is a certainty for parts of South and North Carolina.
One-to-three feet of rainfall is likely in some areas, potentially setting new state records.
Wave heights of 83 feet were measured Wednesday morning in the northeast quadrant of Florence. Unfathomable.
Twenty-to-40 foot waves will come very close to the Carolina shorelines in the coming days. The large waves and swells will propagate outward from Florence and have lasting effects on the entire East Coast including in New England. Life-threatening surf and rip currents will be a concern through the weekend up and down the coast.
Needless to say, if you have friends or relatives in the Carolinas, please urge them to follow all evacuation orders and forecast updates. We will keep you informed throughout the storm here on CBSBoston.com and WBZ-TV.