Posted on 09/09/2018 8:01:18 AM PDT by NautiNurse
...a threefer...
Hurricane Florence Discussion Number 54
NWS National Hurricane Center Miami FL AL062018
500 PM EDT Wed Sep 12 2018
Data from an Air Force Reserve hurricane hunter aircraft along with
satellite imagery and various intensity estimates indicate that
Florence has weakened instead of strengthening. However, while the
hurricane hasn’t strengthened in terms of peak winds, the inner-core
and outer wind fields have continued to expand, resulting in an
increase the cyclone’s total energy, which will create a significant
storm surge event. The upper-level outflow remains impressive and is
still expanding except toward the south.
Florence is moving toward the northwest or 315/14 kt. The new 12Z
global and regional model runs have come into much better agreement
on Florence moving steadily northwestward around a strong ridge
located between Bermuda and the U.S. mid-Atlantic region for the
next 48 hours or so. By late on day 2, Florence is forecast to
approach the southern portion of the North Carolina coast, then slow
down considerably and turn westward within collapsing steering flow,
with a very slow westward motion near the coasts of North and South
Carolina continuing into Friday and Saturday. Corrected-consensus
models HCCA and FSSE remain very close to each other and are quite
similar to the simple consensus model TVCA. Therefore, only a slight
eastward shift was needed to the previous forecast track through 36
hours or so, mainly due to the more eastward initial position based
on the reconnaissance fixes. At 48 hours and beyond, no significant
changes were required to the previous advisory track, which still
shows Florence moving slowly westward across South Carolina and
western North Carolina on day 4, followed by a slow northward motion
up the Appalachian mountain chain on day 5.
A narrow window of opportunity remains during the next 24 hours or
so for Florence to strengthen a little when the hurricane passes
over the warmer SSTs and deeper warm water/higher upper-ocean heat
content associated with the Gulf Stream, and low vertical shear
conditions of 5-10 kt will aid in any strengthening process.
However, significant strengthening is not anticipated due to
Florence’s large and expanding inner-core wind field. By 36 h
and beyond, decreasing ocean heat content along with the slowing
forward speed of Florence will likely produce cold upwelling beneath
the hurricane, inducing a gradual weakening trend. When Florence
moves over the shallow coastal shelf waters in 48-72 h, land
interaction and more significant upwelling are anticipated, which
should further enhance the weakening process. The NHC intensity
forecast remains near the higher statistical guidance through 48
hours, then follows the trend of the decay SHIPS model after that
time.
Although the maximum winds are expected to weaken a little more,
Florence is still expected to remain a dangerous major hurricane as
it approaches the coast. The threat to life from storm surge and
rainfall will not diminish, and these impacts will cover a large
area regardless of exactly where the center of Florence moves.
>Wow! I heard the rains in PA over the weekend were due to Gordon remnants. Can’t imagine the situation when big bad Flo reaches the shoreline.<
Right. I was listening to a local forecast last night. The meteorologist cautioned people not to get complacent because even less than 6 inches would cause dangerous conditions.
There will be floods in and around the area, as then TS Florence comes through. Count on it.
This guy says it’s wanting to strengthen...per hurricane hunters.
That’s almost a quarter of the permanent population. They’re seafaring people, Ocracoke Village has a large fishing fleet. They’ll put their vehicles up on ramps or even drive them into their raised houses through large French doors put there for precisely that reason, then ride it out as they’ve done in the past. Ocracoke is above Cape Lookout, it’s the first inhabited island in the OBX chain. They’ll in all likelihood be OK, and if they aren’t it was their choice to make.
I assure you, I believe that competent adults my make their own decisions about protecting and staying on their property as long as they take consequences without throwing the burden, risk and cost of solving the consequences on the public.
We must be aware that when doing so we create a climate where others, less competent, less prepared or less qualified, follow our example. We saw terrible results from this in Katrina. They thought of themselves as qualified low-land people as well.
If 20 people had elected to stay, I would not have even noted a weather person’s comments. 200 from such a small island seems like capricious behavior to me. That is just my personal opinion. Others will have opinions of their own.
A quarter of the population remaining to me is more persuasive that these people needed to stay for a variety of reasons. Animals. Their boats. They’ve been through countless storms there. This is not a place filled with people living off of welfare. They made the call, there is no real hospital there. They’re on their own and they know it. They’ve always been pretty much on their own, it’s an island, no bridges. Ferry service shuts down, they’re not getting anything off that island but perhaps themselves in private vessels. Easy for you to judge, sitting high and dry. It’s their call to make.
As was pointed out on one of the storm forums, over-reliance on experience in this case can kill. It’s something like a batter facing a pitcher he or she has been up against many times, only the pitcher has a brand new “strikeout” pitch developed over the offseason...
In this case we have a not particularly powerful (”category”) hurricane, but it DOES have the potential to generate an exceptional storm surge, and hang around. Shoot, it’s not likely, but it may even do a loop, and as of the time people on the island would have decided to stay, given the track uncertainty, they might face over time a nearly 360 deg. assault over 2-3 days. How many residents or even their deceased parents have faced that?
My understanding is that many structures on Okracoke Island are on stilts (pilings) and the town (most of the homes?) is roughly 0.75 - 1 mile behind the shoreline; typical elevation of the island is 3 feet.
A 15’ - 20’ storm surge is decidedly possible if the storm stalls in the wrong location. Let’s say we (they) end up with 15’ storm surge. What size waves can continue to propogate over 15’ deep water? Are there, at the very least, shelters that can withstand that for 2 days?
So, you’re studying the weather maps and prognosticating from where? Are you in harm’s way or even potentially so? These people are. They’ve made their decision and are staying. Your worst case speculating from afar does what at this point? Nothing. They made their choice, and will have to deal with the consequences of their decision, Ocracoke will be cut off until the storm has moved on, no bridges just ferry service.
The eye wall is getting disorganized, windspeed is dropping. Other than immediate oceanfront this is turning into a moderate hurricane with some wind damage, storm surge damage on coastal immediate waterfront areas and coastal as well as inland flooding. Flooding could be fairly severe. It always is pretty bad with a hurricane or even tropical storm, though.
These people live this every day of their lives. They know what to do.
Well, my point is that sometimes experience or being too close to a situation can be misleading. Heck, I’ve had long experience lead me astray occasionally. Anyone with such & who is wise recognizes that. Experience is great, even absolutely essential in many situations, but, don’t let it be a straightjacket...
In this case, for one thing, 15’ storm surge with waves over that (my question is still “how big”?) is NOT worst case, and the collapse of the steering currents makes this storm less predictable than most. Has a similar scenario played out in this location, in the last generation or two? The serious weather watchers don’t seem to think so. (BTW, I am not myself making a prognostication - I am relying on others far more knowledgeable than I.)
Wind speed is down, but storm total energy is up, according to the NHC. The storm track has shifted slightly north. Make of that what you will.
I also note that there IS at least a point @ 27’ elevation on the island. Hopefully there is a strong shelter there.
In all this, I am not saying residents should be forced (as in “at gunpoint”) to leave. However, they MAY have made a fatal or very injurious mistake, based on their experience. Hopefully not!
“Prayers up” might not be a bad idea...
There are vegetated, larger inland dunes, unceremoniously called “hills” on that island. There is high ground. A 15 foot storm surge on Ocracoke appears very unlikely at present, however if such a thing were to occur, it’s not the entire island covered to a depth of 15 feet. That depth is the surge on the beach. The beach dune line serves as protection against this. Should there be a “blowout” in the beach dune line then the storm surge will rush through, but not at 15 feet. Storm surge can also affect the island on the sound side, but it’s not typically as severe. You’re talking about a place that floods in a thunderstorm. It’s not as if they don’t deal with high water day in and day out. Again, they made their decision, they’re staying. The consequences of their decision is theirs to bear, there will be no way off that island once the storm comes in until it passes. They know this.
Florence’ winds are weakening too — should help with wave height.
Am closing out here — Moving over to thread #2... :-)
please post and let everyone know you are safe!
Thank Q bitt!
I am safe in Annapolis. I am in the dark about the condition of my house in Wilmington. Near flood zone, lots of trees around and a couple of tornados last night.
I will remain in Annapolis for at least another week until I find out if I have a house to go back to. Hoping for the best!
Thanks much for your concern!!
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