ATL: GASTON - Models

[KWT]

Models showing a pretty strong and slow moving upper trough in the W.atlantic that is almost certainly going to impart a NW motion on the system, the key is where is the system when that trough does arrive, is it sitting at 55W like some models believe, in which case the threat to the Caribbean is a little lower...or does it sit in the E.Caribbean and cut up through the Caribbean like Hortense/Mariyln possibly being a threat for even the C.Caribbean?

All major models though show NO sign of changes with regards to the pattern though of troughing down the W.Atlantic...indeed the models restrengthen that pattern again by 168hrs.

[ColinDelia]

Amusing at any rate...

324 hours


336 hours


348 hours


360 hours

[Meso]

[KWT]

Yeah that GFS looks something like what the GFS tried to do at one stage with DAnielle by bringing it the whole way back west towards the states...that'd be a heck of a long lived system though, by that point we'd be on what something like day 17?

ps, if you want a threat to the Gulf...THAT is the sort of high you need really on the 348-384hrs GFS over Canada!

[ColinDelia]

Wow, KWT. That would be an ACE monster

[AussieMark]

does the GFS have a handle yet? I know originally did not even develop Gaston

[perk]

i still dont think this is going to be a recurver. i feel like this one has gom bound written all over it.
i really want to see what the euro shows tonight.

Why do you feel that has gom written all over it?
Anything to do with where you live?

We're talking like 10 days out at least!

fci you might want to check your map before making an accusation like this.

[KWT]

Yeah the GFS keeps it fairly weak till the Caribbean then slowly strengthens it out right the way till the end of the run this time round.

Probably still a little early for the Caribbean Cruiser system in a La Nina...they tend to come late September time and then eventually they end up developing further west in the Caribbean instead by October.

[KWT]

Of course he could, I'm just looking at what is the most likely option CBS....but we only get better by trying to push ourselves don't we, every bust is a learning curve IMO...

What does seem to occur is the models never really completely kick Earl's remains out of the way, a big upper high forms over Greenland and the upper torugh that lifts out Earl gets stuck around 60W and has to infact dive back ESE as the jet tries to cut under the upper high. This is what causes most of the models to lift Gaston to the north-west or in the ECM/CMC case nearly due north by 168hrs.

I've said plenty of times IF it manages to scoot past that upper trough that dives down then IMO it goes way west of all the models, we'll just have to see, its just too far out as you rightly say to go beyond the threat to the E.Caribbean right now.

[CalmBeforeStorm]

Of course he could, I'm just looking at what is the most likely option CBS....but we only get better by trying to push ourselves don't we, every bust is a learning curve IMO...

What does seem to occur is the models never really completely kick Earl's remains out of the way, a big upper high forms over Greenland and the upper torugh that lifts out Earl gets stuck around 60W and has to infact dive back ESE as the jet tries to cut under the upper high. This is what causes most of the models to lift Gaston to the north-west or in the ECM/CMC case nearly due north by 168hrs.

I've said plenty of times IF it manages to scoot past that upper trough that dives down then IMO it goes way west of all the models, we'll just have to see, its just too far out as you rightly say to go beyond the threat to the E.Caribbean right now.

You're coming to conclusions based upon long range model forecasts and that's just pure folly even regarding the general setup. There's a bit of the choas theory at work here as a slight deviation of the pattern at short range can make very wide variations in the result at long range. The technology hasn't come anywhere close enough yet (if ever) to predict confidently over 3 days and the errors compound expodentially beyond that point.

[KWT]

Very true but powerful features like the models forecast at 168hrs tend to be very forecastable, if you have all the models in broad agreement of a strong upper high feature developing over the far NE Atlantic and towards Greenland and a upper trough between 55-70W then probably 7-8 times out of 10 that is what will happen...and given thats been the pattern since late July its not hard to suggest that may occur...

However thats not me saying "oh this one is going to recurve"...notice I've not mentioned what I think will happen past say 144hrs and the E.Caribbean, because IMO its still too dependant on small scale factors...but I do feel confident of some latitude being gained between say 55-70W...its just how much latitude that is key.

[plasticup]

Amusing at any rate...

324 hours
http://raleighwx.easternuswx.com/models/gfs/06zgfs500mbHGHTPMSLtropical324.gif

336 hours
http://raleighwx.easternuswx.com/models/gfs/06zgfs500mbHGHTPMSLtropical336.gif

348 hours
http://raleighwx.easternuswx.com/models/gfs/06zgfs500mbHGHTPMSLtropical348.gif

360 hours
http://raleighwx.easternuswx.com/models/gfs/06zgfs500mbHGHTPMSLtropical360.gif

Another Bermuda storm would be just ridiculous...

[HURRICANELONNY]

I agree KWT. I also think it's possible that it never gains latitude. Discussion is talking wsw in the future. First it has to get out of the mid-level dry air. Looking a little sick this morning. But then again Andrew looked a little sick to before you know what.

[Vortex]

HWRF 6Z continues to suggest wsw in the longer term


http://moe.met.fsu.edu/cgi-bin/hwrftc2. ... =Animation

[Vortex]

GFDL 6z also continues its trend of SW towards the end of run




http://moe.met.fsu.edu/cgi-bin/gfdltc2. ... =Animation

[lonelymike]

Learn what CBS? How to make a logical and coherent post? Yeah KWT does that. Always enjoy his posts even though I don't always agree with him Long range models are fun to look at but out past 120 its Fantasyland at this point.

[KWT]

WSW motion IMO looks a good call at some point, clearly can see the strength of the upper ridge and I wouldn't be shocked to see this get to 55W below 15N at all...but then it comes down to timings.

I'd just say CBS is right, anything is possible....probably stays weak for a while yet which will also prevent much latitude gains.

[ColinDelia]

True. Tropical cyclone positions beyond 120 hours can quickly become fantasyland but it should be pointed out that the GFS and European do a pretty good job with the position of troughs and ridges through 180 hours. I have to hurry up and head to the office but .. the way that is measured is the 500 mb anomaly correlation. When it is over .6 the position of the troughs and ridges are basically correct. Eyeballing them you would probably agree it was a decent forecast. For those models (and some others) they stay over a .6 correlation as long as it is less than 180 days.
That says nothing about the position of tropical systems and to what degree a tropical system effects the position of ridges and troughs, well I have no idea about that. There's a site out there somewhere that keeps tracks of the 500 mb anomaly correlation for the various models at various timescale. I'll post it later when I get back online.

Guess I kinda agree with both. Anyway,hope this is not too far off topic but I think it is relevant.

[Frank2]

All major models though show NO sign of changes with regards to the pattern though of troughing down the W.Atlantic...indeed the models restrengthen that pattern again by 168hrs.

Yes, no doubt in my mind that the W Atlantic trough will for the most part stay in place for the rest of the season, since it has been there since early July (due to lobes of the polar trough nosing the subtropical high eastward every few days), and with each recurving system and each approaching cold front as the Fall approaches will only reinforce what is already there...

As another topic mentioned a few weeks ago, perhaps this is the year of the recurve - could be...

Frank

[fci]

i still dont think this is going to be a recurver. i feel like this one has gom bound written all over it.
i really want to see what the euro shows tonight.

Why do you feel that has gom written all over it?
Anything to do with where you live?

We're talking like 10 days out at least!

fci you might want to check your map before making an accusation like this.

Please check your PM