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9/30-10/5 Joaquin-Trough Interaction-DISCUSSION/OBS


bluewave

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My Uncle Freddy says the east end is due for a hurricane, but I don't post that to the thread and you shouldn't be posting the HWRF, especially without context.

We have a tropical depression and the main threat cone passes right over the twin forks. I am not sure what the problem is here. You don't see me going on the 6:00 news and telling everyone a hurricane is coming. 

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My, if the strength of a tropical system were irrelevant, I guess we can decommission the NHC! 

 

Noting your caveat about extra-tropical v. tropical (the so called neutercane argument)...there are plenty of extra-tropical cyclones whose intensity made all the difference...Sandy amongst them.

Perhaps you misunderstood my point, or maybe I needed to be clearer.

 

What I was trying to say is that I don't expect a full warm core tropical system to impact Long Island. I believe that a system would be transitioning, much like Floyd and Irene did as they merged with frontal boundaries. That would take the main wind impact and shift it well away from the center (As was the case with Sandy). 

 

Going along that line of thinking, the greatest impacts would be to the North and West of the center, much like a noreaster during the cold season, with a general dry slot developing once the center passes. 

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Oh, yeah, that doesn't count. ;) I don't see anything that favors significant intensification of TD 11... decent odds it goes unnamed. You don't get a hurricane out of a slopgyre moving poleward into 70 kts of shear:

 

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The frontal boundary pushes East, and then eventually retrogrades back towards the coast. Any tropical moisture would merge with the frontal boundary and wherever the lift and frontogenisis are maximized would see prolific rains. Just because I posted a few tropical models doesn't mean that I am expecting them to be correct. 

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Perhaps you misunderstood my point, or maybe I needed to be clearer.

 

What I was trying to say is that I don't expect a full warm core tropical system to impact Long Island. I believe that a system would be transitioning, much like Floyd and Irene did as they merged with frontal boundaries. That would take the main wind impact and shift it well away from the center (As was the case with Sandy). 

 

Going along that line of thinking, the greatest impacts would be to the North and West of the center, much like a noreaster during the cold season, with a general dry slot developing once the center passes. 

 

 

Systems making the transition from warm core to cold core do not suddenly become universally harmless to life & property. Moreover, they do not all instantaneously take on homogenous wind field characteristics.

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The frontal boundary pushes East, and then eventually retrogrades back towards the coast. Any tropical moisture would merge with the frontal boundary and wherever the lift and frontogenisis are maximized would see prolific rains. Just because I posted a few tropical models doesn't mean that I am expecting them to be correct. 

The placement of the front will be key-heaviest precip will be right along the stalled boundary...models still waffling a bit with that.

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Systems making the transition from warm core to cold core do not suddenly become universally harmless to life & property. Moreover, they do not all instantaneously take on homogenous wind field characteristics.

Who said anything about them being harmless?

 

You're trying to imply that I am saying this is some sort of non-event for the coast.

 

When is 6"+ of rain a non-event? I just think that even if we do get a deeper system, the wind won't be as much of a factor as you would normally see with a tropical system of similar strength at lower latitudes. 

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Who said anything about them being harmless?

 

You're trying to imply that I am saying this is some sort of non-event for the coast.

 

 

It never entered my mind.

 

 

With the 80 F sea surface isotherm not far offshore and the tendency of these things to accelerate as they get caught up in the faster mid latitude flow; odds are that any loss of tropical characteristics would be minimal...there just would not be sufficient time or cold water.

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It never entered my mind.

 

 

With the 80 F sea surface isotherm not far offshore and the tendency of these things to accelerate as they get caught up in the faster mid latitude flow; odds are that any loss of tropical characteristics would be minimal...there just would not be sufficient time or cold water.

 

Wouldn't the amplifying trough and frontogenesis over the East overwhelm the depression with baroclinicity, even over warm SSTs?

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It never entered my mind.

 

 

With the 80 F sea surface isotherm not far offshore and the tendency of these things to accelerate as they get caught up in the faster mid latitude flow; odds are that any loss of tropical characteristics would be minimal...there just would not be sufficient time or cold water.

 

 

The 1938 Hurricane, for example, after languishing east of Hatteras for a period, suddenly shifted into high gear as it breached the 35th parallel and moved northbound at a forward speed of approximately 60 mph...a good deal faster than the average automobile of the day could go.

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Wouldn't the amplifying trough and frontogenesis over the East overwhelm the depression with baroclinicity, even over warm SSTs?

 

I'd leave the ultimate solution to the models; but any time a tropical system interacts with a cold front, the C.F. will almost always tear the tropical storm to pieces...though it might make a more prolific rainmaker of it for certain areas.

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The 1938 Hurricane, for example, after languishing east of Hatteras for a period, suddenly shifted into high gear as it breached the 35th parallel and moved northbound at a forward speed of approximately 60 mph...a good deal faster than the average automobile of the day could go.

You're assuming that the system would be accelerated, and that can be a likely scenario. In this case though, you essentially have a stalled or retrograding frontal boundary with a blocking regime in place. That doesn't scream acceleration to me. 

 

It sounds as if the 38' system was stalled South of the area until a weakness in the ridge opened and it was eventually picked up by a trough.

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I hope the metro area doesn't miss out on the best rains to our west Wednesday and to our east Saturday 

I highly doubt that is going to happen. The NAM is likely too far NW at this range (Assuming that is what you're referencing). The front needs to retrograde back West so that the tropical system can be tugged back towards the coast. 

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This setup is eerily similar to that of November 9, 1977, which I remember all too well.

 

Please refresh our collective memories...as I don't recall it in the slightest...though I might still have been hung over from Jackson's 3 HR game against the Dodgers in the previous month...

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The GFS keeps the main focus NW of the area through 60 hours. It still has around 2" for the area which is by no means dry, but parts of Upstate NY, PA and Western New England are 3-5". Again, this is just through 60 hours.

 

The GFS is never to be used for precipitation estimates...it is a global model... mesoscale models will be more revealing...I think we have been through this before.

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the nam has shown a different precip pattern each run

 

De rigueur for that sad little model...one mesoscale I would avoid like the plague...though you already knew / know  that.

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De rigueur for that sad little model...one mesoscale I would avoid like the plague...though you already knew / know  that.

 

Inside 48 I'd take the Canadian short range models above all others...maybe the ECMWF next...maybe some offshoots of the NAM third...like the ARW or NMM...or WRF....they've done pretty nicely in recent years...at least in the winter...not sure of their abilities with tropical systems.

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The 12z GFS focuses the second event over SE NE. Basically the frontal boundary makes it further East and then doesn't retrograde as much.

Climo would favor that solution as well.   Need some pretty good blocking or the atlantic ridge to push it all west a bit

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edit-later in the run it does hook back NNW a bit, dumping good rains over CT and LI-east of there gets demolished verbatim

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I highly doubt that is going to happen. The NAM is likely too far NW at this range (Assuming that is what you're referencing). The front needs to retrograde back West so that the tropical system can be tugged back towards the coast.

I was pretty much referring to all the models as they show this split now

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