Area from NW Caribbean across Cuba to the Bahamas (now INVEST 99L)

[AJC3]

Peeps,

Granted, this probably pushes the limits of "incipient disturbance", but I combined a couple of threads - this one about the NW Caribbean, and another about the developing CENTAM gyre, into a general thread about the western Caribbean. I also moved some of the pertinent posts here from the extended/global model thread, which had been posted since the OP started this one. I strongly suspect we'll be watching this area for the better part of the next week or so until an Invest is eventually declared.

So fire away at will in this thread...

[sma10]

We also must remember the western Caribbean is untouched this year so far. The heat content there is far higher than what fueled Harvey, Irma, Jose and Maria. If shear is near zero and outflow channels established, it can support a Wilma-like storm or stronger.

And even more disturbing, there are model hints that the W Carib may fire off more than just one cyclone this season.

[GCANE]

GFS Run-to-Run is beginning to develop a closed off 700mb vort around Saturday 9/30.
Currently has it in the EPAC just off shore of Panama.

[GCANE]

A little hint from 00Z Euro of a closed off 850mb vort possibly developing east of Panama in 144hrs and pushing north into the GOM.

[OntarioEggplant]

I'm kind of amazed at how much the GFS and Euro agree that something will happen down there and move into the Gulf during roughly the same time period so far out. It's a bit disconcerting.

[WeatherEmperor]

The 12z Euro develops an area of low pressure around 192hrs in the NW Caribbean and moves it WNW towards the Central GOM at 240hrs. Extrapolate the motion and it goes to TX/LA long range. It does not look like a developed tropical cyclone but seeing low pressure go that direction is always a worry






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[gatorcane]

If you look carefully at the 12Z ECMWF run 850MB vort charts, the catalyst for possible development in the Western Caribbean is the tropical wave east of the southern Lesser Antilles:

[gatorcane]

It looks like the 12Z EPS consensus shows a large break in the ridge over the EGOM and Florida unlike the ECMWF operational which shows a strong ridge over the northern Gulf (image below). Consequently looking at the MSLP anomalies from TT, it appears there are a number of ensembles turning the area north in the NW Caribbean:

[GCANE]

18Z GFS is building a stronger gyre long range.
A closed 850mb vort coming off the Yucatan at 264 hrs.
Moving north into the GOM.

[1900hurricane]

Some very preliminary thoughts, so don't take this to the bank, but I'm thinking chances are pretty good that a developing system will be more of the sloppy monsoon depression variety, at least initially. I'm not sure there will be enough residence time for a more intense system since it seems like it lifts into the Gulf of Mexico relatively quickly. Even sloppy monsoon depression type systems have a set of hazards though (see Francis '98), and this is far from a guarantee considering the forecast range at the moment. Considering the potential ridging across the CONUS, I'll be watching this carefully in SETX. Impacts here are rare this late in the season, but not unheard of.

There are also some hints in the medium range guidance that the Central American Gyre may be a more persistent feature, so the sloppy monsoon depression that is commonly featured in the recent guidance suites may not be the only system to emerge once the entire sequence has played out.

[otowntiger]

Some very preliminary thoughts, so don't take this to the bank, but I'm thinking chances are pretty good that a developing system will be more of the sloppy monsoon depression variety, at least initially. I'm not sure there will be enough residence time for a more intense system since it seems like it lifts into the Gulf of Mexico relatively quickly. Even sloppy monsoon depression type systems have a set of hazards though (see Francis '98), and this is far from a guarantee considering the forecast range at the moment. Considering the potential ridging across the CONUS, I'll be watching this carefully in SETX. Impacts here are rare this late in the season, but not unheard of.

There are also some hints in the medium range guidance that the Central American Gyre may be a more persistent feature, so the sloppy monsoon depression that is commonly featured in the recent guidance suites may not be the only system to emerge once the entire sequence has played out.

Sounds like a decent analysis- I too noticed the set up that could possibly be steering the system more NW than the typical ne for this time of year.

[GCANE]

Strong 850mb vort / TPW moving north from Gulf of Tehuantepec over flat portion of Mexico , east of Oaxaca, into BOC.

http://tropic.ssec.wisc.edu/real-time/m ... anim=html5

Heavy convection starting to fire in the BOC.
Persistent surface low over Yucatan.
355K PV anomaly to the NE.

A lot of ingredients coming together - keeping an eye on this.

[GCANE]

[Nimbus]

Looks like an anticyclone over the center of that lowest surface pressure.
Models were all talking about something developing at 144-240 hours not 72 though.

[LarryWx]

9 of the 50 (18%) 0Z EPS members develop this into a H within the interval 10/6-11 but remember that the ensemble members are at a lower resolution (I think) and SLPs would likely tend to be underdone in many cases in those that develop into a TC.

[SuperMarioBros99thx]

I'm gonna guess that this will be named OPHELIA. Want to know that why i going to guess that name? Wait until next day (If you are Indonesian).

[Tireman4]

[quote="otowntiger"][quote="1900hurricane"]Some very preliminary thoughts, so don't take this to the bank, but I'm thinking chances are pretty good that a developing system will be more of the sloppy monsoon depression variety, at least initially. I'm not sure there will be enough residence time for a more intense system since it seems like it lifts into the Gulf of Mexico relatively quickly. Even sloppy monsoon depression type systems have a set of hazards though (see Francis '98), and this is far from a guarantee considering the forecast range at the moment. Considering the potential ridging across the CONUS, I'll be watching this carefully in SETX. Impacts here are rare this late in the season, but not unheard of.

You are correct young sir...rare, but not unheard of on the Upper Texas Coast. The latest was Jerry in 1989..an October hurricane....

[blp]

I don't know if we have a thread for this but the 12z GFS is coming in much stronger with this disturbance starting in 72hrs. The Euro also has this but looks more disorganized and delayed starting at 96hrs.

12z GFS:


00z Euro:

[gatorcane]

Looks like this has something to do with the convection blowing up south of Cuba. I expect NHC will mention this area in the next 2pm outlook. Could be a good coupe for the GFS showing this well in advance (from model output several days ago).

[LarryWx]

The 12Z GFS has the strongest low yet for its runs. On Friday, it has a sfc low form over S FL. Then it moves NE to 175 miles E of Daytona late on Saturday and strengthens it to 1009 mb. Then it moves back SW to over S FL late on Sunday followed by weakening as it then moves westward into the GOM.