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SNE "Tropical" Season Discussion 2021


WxWatcher007
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Since I start 98% of the tropical threads on AmWx I figured it was time to start this one. 

Last year we had TS Fay landfall to the south of the region, essentially a direct hit by TS Isaias, and a relatively close approach by the post tropical remnants of Hurricane Teddy. 

Most of the time tropical and New England in the same sentence is akin to snow in Las Vegas.  Doesn't mean we can't talk tropical.  

 

That said,  TS Elsa might be worth a casual eye in the coming days as some operational guidance tries to take it northeastward after a trip through the eastern Caribbean Graveyard. As always, very low probability deal up this way, especially this far out, but it's the first real tropical worth discussing.

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33 minutes ago, STILL N OF PIKE said:

What is the steering pattern Tuesday -Friday along east coast and is there much confidence in it . 

IMO, the steering pattern actually looked ripe for a close US approach a week ago. If you look at the 500mb look on both the EPS and GEFS, they're pretty similar. A strong subtropical ridge developed and has been in place to steer whatever was to develop in the MDR to the west, which is happening now.

We also know that our crappy holiday weekend trough comes in creates a weakness that almost certainly turns what we now know to be Elsa. 

The devil is in the details though. Timing/placement/strength of the ridge and trough determines when the slow down and turn happens, as well as the sharpness of the turn. We also have to watch for center reformations with this as it is still a bit decoupled and moving at a ridiculous pace to the WNW. 

I'm not all the way in the GFS camp, but frankly, I think the Euro/EPS is too weak and too quick to shunt Elsa NW and then NE. I really like the NHC track right now and perhaps a more gradual turn NE in the wake of the trough that allows Elsa to scrape the SE coast and head OTS south of here. That's just speculation though at this range.  

I know you didn't ask this, but one thing to be considered is what happens if it misses Haiti/DR in favor of a more westward track. The NHC is admittedly conservative with their forecast (also signaling they're tossing the Euro for now) and that makes sense. 

A further west track would not only place Elsa in the best thermal environment in the basin, it'd coincide with a slowdown over those waters and reduction in shear as the system reaches the periphery of the ridge and sees less influence from trade winds. For something coming relatively quickly, this is a highly uncertain forecast. This one has some legit potential though if it can get far enough west without land interaction. b8UyUCM.jpg

 

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I think it impressive to see this kind of structure in this region of the Atlantic, at this time of year, in the first place.   I mean I suspect there's been CV TC in this region this early, before ..and probably all tropical climate months - but it's still rather rare to see such a robust long track TW succeed gestation into this kind of panache.  That's a big circulation with a very coherent cyclostrophic cinema on satellite. 

It's moving too fast in the near term.  It seems like the low level is in danger of outpacing the mid level column/stack, as at times the inner rotational axis gets really close to the western edge of deeper convection but then is saved by some flare up wrapping around. It's probably right at the boundary.

You know this could be one of those systems that is tenacious  - you gotta watch out for those?  The ones that fight. Through it all and challenges, they get through the gauntlet of adversities - it's like an indicator for what could become of them if said adversities abandon.  Look out!    Hurricane Hotdog Bun slows down for any reason and that "development momentum" takes its revenge

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15 minutes ago, STILL N OF PIKE said:

Let’s see if this is has more trouble due to increased difficulty with a tilted / non aligned centers . At its forward speed ..that is something that could undermine it’s development and would cause it to underwhelm. 

 

Definitely has a chance to struggle, but kind of like like Tip said, as long as there’s convection near the center, it’s more likely to be resilient. All it takes is one burst to breathe new life into it so to speak. 

11 minutes ago, Cyclone-68 said:

I kind of assumed this would be a S Florida/Gulf storm. Is there  any chance this turns right  at the Herbert Box to become an East coast issue  (assuming it stays together)?

I think everything from Pensacola to OTS ~100-150 miles off the coast is still on the table. SE US shouldn’t take their eyes off this one yet IMO. It’s always more lottery odds up here for impacts, as you know. 

I think I have a sense of the most likely general evolution, but this isn’t an easy forecast.

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37 minutes ago, Cyclone-68 said:

I kind of assumed this would be a S Florida/Gulf storm. Is there  any chance this turns right  at the Herbert Box to become an East coast issue  (assuming it stays together)?

Mmm   not to be presumptuous in putting intent behind your question, but it 'sounds' like you're buckin' for a Long Island Express somewhere in there ... LOL

The entire hemisphere could change in favor .. but at present, most leading indicators albeit modeled are only vaguely suggestive of large scale synoptic aspects that are common with that sort of entertainment.

There are certain ideal modes of the atmosphere we'd like to see to get one to needle a pathway from 50 Mi E of Hatteras to EEN NH.    

1  ..  you want some sort of weakness or trough ...but not too excessively deep, parked in the vicinity of West Va. 

2   .. some form of western-limbed NAO blocking is in the process of emerging. 

The flow between these too governing atmospheric modes directs whatever's near the Bahamas to turn N around the trough over WV, where/when it accelerates N but while doing so is prevented from curving E by the block downstream with the -NAO. 

Anyway, the NAO is neutral negative in the mean at GEFs/ CPC, while the PNA is bouncing neutral positive - it's not altogether impossible in those modes.  It's probably why we are seeing pulled up N around the longitude of FL at all.. But the STR in the Atlantic now is too much and will probably direct this thing too far W ...effectively missing the key slots.

The other aspect to keep in mind, there's no categorical paragons that have to be obeyed in these matters.  It could go too far W of climate, but then cross Cuba's flat land aspects only losing 20 kts of momentum, before re-emerging, cutting across S Florida's equally impressive "10,000 foot mountains" before ending up moving N over the Gulf Stream east of the lina's.   Oops.

 

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41 minutes ago, WxWatcher007 said:

Definitely has a chance to struggle, but kind of like like Tip said, as long as there’s convection near the center, it’s more likely to be resilient. All it takes is one burst to breathe new life into 

I think it’s going to want to organize / allign itself prior to entering the less favorable East Caribbean (graveyard ) if it’s going to be be more than a TS . So I think the organizational progress next 36 hours is very important and may determine wether the Euro or Gf’s/HWRF is correct 

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24 minutes ago, STILL N OF PIKE said:

I think it’s going to want to organize / allign itself prior to entering the less favorable East Caribbean (graveyard ) if it’s going to be be more than a TS . So I think the organizational progress next 36 hours is very important and may determine wether the Euro or Gf’s/HWRF is correct 

There is that climate gauntlet down there .. I've heard all kinds of hypothesis - the best being dry air gets sucked off the S. Am N coast but ... whatever the cause, it is also muddled by the the notion, the Euro can't ever organize a TC on it's own.

It does really really good after the fact.

It misses the genesis much or the time, and then along about the time the genesis has finally become an actual presence in the initialization grid/interpolation, suddenly it swoops in, "Okay other models this is what's gonnna happen..." 

The GFS is wicked pisseed.

No but it does have a stingy record with genesis in the tropics and so long as this thing is .. you know 1000 mb and/or less than 50 kts I'm not sure if the Euro's just being coincident with climatology in this case ?   interesting -

Right now the center is exposed from what I am seeing. The low level aspect has outpaced the convection at least for the time being. Needs new eruptions

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Euro has been trash with tropical.

Anyways the pattern next week is rather intriguing. One thing we've noticed with the past few or several cold front passages is cold fronts aren't entirely progressing very far through the reigon...in fact, they've been getting held up nearby and we've seen waves of low pressure develop along them. GEFS shows a height configuration next week which would favor the same exact scenario with next week's FROPA

gfs-ens_z500a_atl_26.png

Now this isn't exactly being shown in the ENS mean due to smoothing but that trough dipping through southeast Canada into parts of the Northeast is not bad looking...and could certainly capture Elsa as it moves through the mid-Atlantic. 

This might be a situation where the 500 look isn't striking at first glance for a hit but this isn't a storm that's riding the coast. In fact, given the potential track of Elsa you could argue this 500 look supports the capture potential. 

Have to look back but I wonder if this configuration is similar to what brought the remnants of Katrina up this way. We had a pretty decent severe threat with that but were too capped in the end.

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8 minutes ago, weatherwiz said:

A little shocked at that given the high clustering towards the western fringe of the cone. 

Don't worry you can always add Alabama to a cone!

 

122714_5day_cone_no_line_and_wind.png.7b836e4050d9c14116a609e149db448d.png

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50 minutes ago, weatherwiz said:

A little shocked at that given the high clustering towards the western fringe of the cone. 

No track edits came with the special advisory. I actually think they should wait until guidance has some data from recon. What they have now is well within the envelope of possibilities. 

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4 minutes ago, Cyclone-68 said:

This storm can’t wait to travel across the ocean..28 mph?  I can’t remember an east to west storm moving that fast 

It’s moving at a record pace for that part of the basin at that intensity. Practically supersonic. 

 

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46 minutes ago, WxWatcher007 said:

It’s moving at a record pace for that part of the basin at that intensity. Practically supersonic. 

 

Mm...

I wonder. 

 -some years ago, NHC began seemingly to bias their cyclone ratings based upon nearing smart-phone distracted population.  LOL -   

I am not sure that is the best practice. This thing may go over the Islands down there with impressive sub 'cane gusts, and then the reliant civilian becomes accustomed pretty quickly into thinking, "I just experienced a hurricane" 

- this plays into their response tactic in future events, because they remember and think they really did. 

 

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2 minutes ago, Typhoon Tip said:

Mm...

I wonder. 

 -some years ago, NHC began seemingly to bias their cyclone ratings based upon nearing smart-phone distracted population.  LOL -   

I am not sure that is the best practice. This thing may go over the Islands down there with impressive sub 'cane gusts, and then the reliant civilian becomes accustomed pretty quickly into thinking, "I just experienced a hurricane" 

- this plays into their response tactic in future events, because they remember and think they really did. 

 

I hear ya, and I think that's true generally, but the obs down in the islands so far have been impressive with sustained hurricane force winds in Barbados and a gust to 86 mph. It's a small core so most miss that, but this one seems to be the real deal with ground truth. There's also that old rule of thumb I've heard before that it's sometimes worse to be hit by an intensifying TS than a weakening hurricane. 

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6 minutes ago, WxWatcher007 said:

I hear ya, and I think that's true generally, but the obs down in the islands so far have been impressive with sustained hurricane force winds in Barbados and a gust to 86 mph. It's a small core so most miss that, but this one seems to be the real deal with ground truth. There's also that old rule of thumb I've heard before that it's sometimes worse to be hit by an intensifying TS than a weakening hurricane. 

Yeah... heh, hence the "I wonder"

If that's the case than that's the case,  "sustained" ... but the over-arcing concern is valid, and it is true there is a tendency to hike ratings. 

I don't know how much of that is policy or just humans buns making decision.  Haha

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