Life-threatening storm surge and extreme wind damage is becoming more likely from Major Hurricane Florence in portions of South and North Carolina, which prompted the National Hurricane Center to issue a Hurricane Warning and Storm Surge Warning for more than 350 miles of coastline Tuesday afternoon.
Florence is then likely to slow to crawl or even stall, potentially producing catastrophic inland flooding across a large area of the Mid-Atlantic and Southern Appalachians.
The wind and surge warnings extend from South Santee River, South Carolina, to Duck, North Carolina, including the Albemarle and Pamlico Sounds and the Neuse and Pamlico Rivers. A Hurricane Watch continues for areas south of the warning to Edisto Beach, South Carolina.
Hurricane Florence grew in geographic size Tuesday, ensuring its life-threatening wind and surge impacts will spread far from the center. The Category 4 storm is also expected to slow down significantly once it nears the coast, leading to potentially catastrophic flooding across portions of South and North Carolina. The monster storm could also resume forward progress to the southwest, placing more of South Carolina at risk for high winds and extreme rainfall.
The eye of #Florence has grown to 32 nautical miles, a sign that the wind field with the Category 4 storm will also be growing in size. A larger storm can be a more stable storm, thereby delaying its rate of weakening when it moves inland. #scwx #ncwx #scein #flwx pic.twitter.com/uqRpH5Ys8n
— Jeff Huffman (@HuffmanHeadsUp) September 11, 2018
Florence completed an eye wall replacement cycle Tuesday, which will allow the storm to strengthen again over the next 24 hours. During this time, Florence's wind field is also expected to expand in size. As of 5 pm Tuesday, hurricane-force winds extended outward up to 60 miles from the center. and tropical-storm-force winds extended outward up to 175 miles. It's entirely possible both of those numbers will double by the time Florence reaches land.
The National Hurricane Center has made little change to their forecast track on Florence through Friday, which brings the storm close to Wilmington, North Carolina by midday Friday. Thereafter, forecasters at the National Hurricane Center express low confidence on where Florence might track due to a “complete collapse” of the steering currents pushing it along presently. A weak steering pattern is expected through the weekend, which only exacerbates the threat for extreme flooding.
The wind risk from Florence will be near and just to the northeast of where it comes ashore, which at the present time is most likely to be in the PeeDee region of South Carolina and much of southeast North Carolina. The risk for wind damage will most certainly spread inland, but to what extent will be determined by a more confident forecast in the track of Florence beyond landfall.
Life-threatening storm surge of 9 to 13 feet is expected from Cape Fear to Cape Lookout, including the Neuse and Pamlico
Rivers. The storm surge is likely to be in the 6 to 9-foot range from North Myrtle Beach to Cape Fear, and Cape Lookout to Ocracoke Inlet. 4 to 6 feet of storm surge is forecast from South Santee River to North Myrtle Beach, and Ocracoke Inlet to North Carolina-Virginia Border. 2 to 4 feet of water above normally dry ground can be anticipated from Edisto Beach to South Santee River.
The inland flooding risk will develop over time after Florence moves inland. In some areas, the heavy rain risk could continue through next Tuesday. Due to the slow nature of the storm, Florence could produce up to 24 inches of rain near and north of where it comes ashore over a three or four-day period. Rainfall totals further inland may also be this high over a five-day period as the storm slowly weakens and meanders through North or South Carolina. Amounts this high could not only cause flash flooding, many rivers are likely to experience major - possibly even catastrophic - flooding for several days following Florence.
As with any hurricane, there will also be the risk of tornadoes in its outer bands. This is most likely to occur near and north of where Florence moves inland, which would be across portions of southeast North Carolina and maybe in extreme northern sections of South Carolina.
The South Carolina Emergency Information Network will continue to monitor the progress of Hurricane Florence and provide updates on public radio stations throughout the state, and on the @SCPublicRadio social media accounts.