typhoon_tip
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Folks,
The trends are converging on a potential that has some chance to be catastrophic for the upper MA and Long Island - potential on this 18Z run....even more enhancing of a suggestion for EC threat, which has been emerging. It's time to at least give this a mention. The actual risk is low at this time, but given to what is at stake...
Deep layer steering is expect to halt the N tug we have seen from TD#6 today, as the mid latitude trough between 40 and 55W lifts out.
Most operational global models and the majority of the ensembles argue for ridge eruption replacing this trough and adjacent areas with rising heights and attending surface pressure pattern. This is supported by -NAO differentiating toward positive values this week, which "should" signal a pressure rise and ridge type blocking result...effectively stopping any hope at recurvature.
Nothing is absolute in this game...particularly at these time frames but..., there is multi-guidance, multi-model support for a west turn and the eventuality of:
1) Blocking preventing recurvature
2) +NAO teleconnector of troughing emerging over or near the longitude of the E cordillera, which would impose a deep layer southerly steering component up-down the length the EC. This in tandem with a +NAO ridge near 45-50N/60W is becoming a bit too much like an analog for other notable EC 'canes of lore for comfort.
This is preliminary threat assessment. 18Z takes this to nearly 140kt borderline super hurricane (Cat 5) by 144 hours. Deep layer favorable shear profiles and lacking earlier season SST processing, combined with attenuation of plaguing SAL all point to "the possibility" that extreme favorable parametrics are coming together for any would be...
John
Edited by typhoon_tip (Sun Sep 03 2006 10:09 PM)
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Clark
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It will be interesting to see how the evolution of TD 6 & the synoptic environment plays out over the next few days. There's pretty good agreement on enough ridging to send TD 6/likely eventual Florence westward in the general direction of the Bahamas, but what happens after that is still up in the air. I'm seeing a lot of tendencies for disturbances to continually butt up against the western side of the building ridge, but nothing to completely break it down as they all ride along its northern periphery.
While strong storms have a greater proclivity to find weaknesses in a ridge, they also generally have a greater proclivity to diabatically enhance them through warming aloft with their outflow. I have a feeling that the ultimate track of this one is going to depend heavily on how much of a disturbance can slide across the NE US toward the western edge of that ridge as the storm gets in that vicinity. That could be the difference between a landfall in the southeast, or a track up the coast and out to sea. We've had three storms already sorta ride the coast this year, and while I'm not one to put a lot of stock into the idea of "once a channel is set up for storms to follow, they all tend to do so throughout the season" -- it's not out of the realm of possibility that this one eventually does the same. Question is, where? Thankfully there is the whole week ahead to figure that out.
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inHISgrip
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I just checked out the run and believe I saw what you are speaking of. As it gets off of the E coast of Fl a N/NE turn takes place and drives the storm to the upper east coast. However, rather then going back into the atlantic you are wondering if it will drive it's self into the upper e coast. Do I have it about right?
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typhoon_tip
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Exactly...
But Clark has just mention something I also agree with ... The western end of the ridge that is very likely to evolve as planned will key in this/that.
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craigm
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Typhoon, I had no problem with your post on the main forum. Even though it was a little over my head, I enjoy that kind of info as it forces me to research meaning. I love it keep it up!!!
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typhoon_tip
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Clark,
If you are interested... TPC has stated that there was some kind of a problem with the ocean coupling for the 18Z run and that they believe the alarming intensity trend is a result...
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Clark
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Noticed that, wish I knew more about what they were getting at with that. All of those <900mb runs for Ioke in the Central Pacific were because the ocean coupling doesn't extend to the CPac, but it is automatically there in the Atlantic. Perhaps it crashed or accidentally got turned off with this run. Quite odd. I wouldn't be surprised to see later runs show a similar evolution, though, coupling or not.
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Steve H1
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Certainly it is premature to talk about the details of an east coast landfall, but it is a possibility. The fact that the DEEP trough moving through the central north Atlantic will eventually be replaced by ridging in its wake may be showing a change in the pattern....which concerns me. We haven't really seen any strong ridging resembling a Bermuda high, and this summer's pattern could foretell an Indian summer setup, with ridging taking shape and pumping up as TD #6 gets organized. Even a ridge-trough-ridge handover situation could evolve, which would put the SE US in a threat zone. I grew up on Long Island and have seen several hurricanes come through, and generally the cooler SSTs and accelerating movement once the storms approach 40N has done little in the way of damage, the exception being of course the '38 LI express, which fed off gulf stream waters and turned NW, creating the Shinnecock Inlet. I don't buy into the hype of a catastrophic hurricane in the tri-state area, the record books just don't show it. Yes, I guess anything can happen but those events are less than once in a lifetime. We never experienced an intensifying hurricane west of Port Jefferson, and the only "normal" cane I remember was Cat 1 Hurricane Belle. Gloria fell apart as she ripped up the coast and shredded apart as well. Not saying it can't happen, but conditions have to be beyond ideal for 'Catastrophic." That said, in a season that has fortunately not lived up to the expectations of forecasters, I'm still very concerned about this upcoming pulse of activity, especially the east coast of Florida/Georgia and the Carolinas. After the heartache of 2004 and 2005, this September surge has me a bit nervous. Many folks I talk to say we made it through this year, but it isn't over yet. It only takes one and one more I don't want to deal with. There is even the possibility that this could pass through the Straits and into the GOM. I just have a hunch that 2006 is going to leave a mark somewhere. Let's hope its up in the north Atlantic where it can fizzle out. Cheers!!
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HanKFranK
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watching ioke make that long run across the pacific as a large typhoon sort of got my hackles up, as after listening to joe bastardi a few years back and observing the time-delayed symmetry of synoptic features in the pacific to atlantic... seeing a storm with a similar type track in our basin gets me a tad worried. right now, what i'll call future florence has a leftward bending track under a large western atlantic ridge, the sort of path that in september tends to generate very large and dangerous hurricanes.
usually these things peak out south of bermuda and weaken as they recurve off or near the east coast. in recent years two hurricanes, floyd and isabel, had similar type tracks. might also qualify. these became extremely powerful on their westward run, then began to feel shear and subsidence, screwed up an eyewall cycle and lost power. usually one of these broad hurricanes can do an eyewall cycle or two, then gets permanently gimped with a large ragged eye that never can contract again. the ones that threaten to come in as major hurricanes usually don't keep a well-structured inner core if they go through cycles while recurving above about the tropic of cancer.. so if this is going to be one of those storms to run the east coast, it'll probably show up on our doorstep around september 14 and be a category 2 or so. usually to get a major hurricane to cross the u.s. coast you need it to form relatively close in, intensify at a regular-ish rate, and hit about 4-7 days after developing. longtrackers sometimes hit as majors, but it doesn't seem to happen as often. i'm just talking in generalities, because all we have is a tropical depression with early signs saying it will take on the profile of a classic east coast hurricane.. but many of these find a way to recurve early.
anyhow, long story short, like tip and clark and others... early model runs i'm seeing make me suspect that this will be a large hurricane that will start getting lots of airtime late this week and weekend especially.. and that may threaten the east coast around mid-late the week after.
that wave trailing it has an interesting future in model runs as well. some show the large wake-trough enhanced by the outflow jet of 'florence' as chewing it up. others keep it in an upstream 'sweet-spot' that allows it to develop into a significant storm as well. quite often trailer storms end up shearing out, but there have been some notable storms trailing large hurricanes that eventually break free of the oppression and make their own mark (i.e., frederic and to a lesser degree fran).
man, in a 'normal' season.. it's these F, G, H, I storms that usually are the atlantic longtrackers.
HF 0454z04september
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typhoon_tip
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It's definitely true regarding long trackers, vs a storm such as Bob ('91). There is a propensity there for them to coincidently enter an eyewall replacement cycle near the latitude of Bermuda, after which, the trough that is approaching the EC (which is also necessary to capture in one form or another), imposes some kind of shear at a vulnerable time... Thus, the re-intensification prospects after replacement are irreparably harmed. Isabel is an example of this, but also had a random dry air insert near the GA/FL Coastal waters; that got involved and didn't help. Gloria in '86 did this, too... It was 155mph near 55W and when it was recurving it suddenly weakened to Category 2 or something less exciting like that..
Still, despite the climate behavior and the reasoning behind it... it is not impossible that one day something unique could transpire - as you also alluded. Think of '38 in New England, and Blue Hill had sustained 180mph winds because a category 3 hurricane was moving at nearly 50mph when it fisted into the bowls of SNE like astroid impact..
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inHISgrip
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Ty,
This seems to be starting to play out more and more as to what you were talking about on Sat. night. It seems to me the runs more and more are moving to the n/ne. Any thoughts.
But, I must say it is still so early. But notice the wording we=here they noy say the storm w move Nw or NNW rather then W at the end of the forecast cycle.
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scottsvb
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Im not going into detail with this system cause the chance of this hitting south of North Carolina is about 10% and the outerbanks or Cape Cod 20%... strong trough off the east coast will push Florence N along 65-70W and out to sea.
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