Florence, now a hurricane for the second time, is a strengthening hurricane likely to affect the US east coast south of New York and north of Central Florida, where tropical force winds may arrive by late Wednesday. The exact area to be affected is not yet known. Florence is likely to be a very strong hurricane.
There are now very few models that show Hurricane Florence not hitting the east coast of the US.
Florence is fairly likely to come ashore on the east coast somewhere between the Georgia-South Carolina border, north of Savannah, and Chesapeake Bay south of the Maryland-Virginia border. The current bull’s eye is near Wilmington North Carolina.
If the storm turns way to the north, regions including Maryland and Southern Delaware would likely be affected. If the storm turns way to the south, regions in Georgia would be affected. In all cases, how far the storm heads inland, over what time, and now wet it is, will have an impact on interior flooding, which is very likely to be be significant.
The storm surge near the point of landfill is expected to be significant.
Almost all Atlantic hurricanes reach a maximum strength while still at sea, then slow down a bit as they head inland. I believe this is in part because the warmest waters are usually a bit off shore, as well as other factors. Florence will be passing over waters that are quite a bit warmer than normal, due to global warming. It may also be the case that those waters are warm at depth, a feature of climate change that enhances storms. So, we can expect Florence to become a very strong storm, then reduce in strength to be merely a very strong storm.
In other words, there will be breathless reporting that a Category Four storm is heading for the US but the US will actually be hit by a strong Category 3 storm. Don’t be fooled that this storm is not going to be powerful.
One of the things Florence is likely to do is to curve northward as it approaches the bulging Carolina coast. The exact angle at which the storm makes landfall, and the exact location, will make the difference between a very bad hurricane and an epic disaster the likes of which have not been seen since whenever. The front right quadrant of the storm could push a huge storm surge into a restricting estuary with a city on it. One way or another, someone’s gonna lose themselves some barrier island.
Timing
By late evening Wednesday or a bit later, tropical storm force winds are likely to be on shore somewhere along the east coast. That will make being at the beach dangerous, and damage from winds and waves will commence here and there.
Early in the morning on Thursday, September 13th, Florence will be off shore and close enough to be having a strong effect on land. At that point we’ll know a lot more about where the most dangerous places to be are, but evacuations will have hopefuly already been started over a larger area. By the next morning, Friday, Florence will likely have made landfall somewhere. Starting in the wee hours of the morning on Friday and extending for the next few days, inland flooding will be severe, somewhere.
However, the forward speed of the storm can change quite a bit, so maybe this will all happen a bit earlier. Or later.
Estimates of intensity show the storm peaking in about 96 hours at 125 knots (144 mph), putting Florence in the middle of the Category 4 range. There is a very good chance the storm will be just transitioning from Category 4 to strong Category 3 at about the time of landfall.
The National Hurricane Center says:
There is an increasing risk of two life-threatening impacts from Florence: storm surge at the coast and freshwater flooding from a prolonged heavy rainfall event inland. While it is too soon to determine the exact timing, location, and magnitude of these impacts, interests at the coast and inland from South Carolina into the mid-Atlantic region should closely monitor the progress of Florence, ensure they have their hurricane plan in place, and follow any advice given by local officials.
FORECAST POSITIONS AND MAX WINDS
INIT 09/1500Z 24.4N 56.3W 65 KT 75 MPH
12H 10/0000Z 24.5N 57.4W 80 KT 90 MPH
24H 10/1200Z 24.9N 59.3W 95 KT 110 MPH
36H 11/0000Z 25.6N 61.7W 105 KT 120 MPH
48H 11/1200Z 26.4N 64.5W 120 KT 140 MPH
72H 12/1200Z 29.0N 70.8W 125 KT 145 MPH
96H 13/1200Z 32.2N 75.8W 120 KT 140 MPH
120H 14/1200Z 35.0N 78.5W 85 KT 100 MPH…INLAND