West-Central Caribbean Tropical Cyclone (Is Invest 99L)

[Blown Away]

Joe B tweeting about the potential.

[HURRICANELONNY]

Is this 10 day ETA going to be here on Christmas?

[cycloneye]

I see consensus building for something to develop in SW or Western Caribbean but track is still not clear. Already TWC mets say watch area and NWS offices are mentioning it.

[jlauderdal]

Is this 10 day ETA going to be here on Christmas?

i like the thread title, 10 day eta and we have been on this for about 10 days..

anyone take a look at the ETA to see what it does with our 10 day eta system

[wxman57]

All the models remain in good agreement on the development of a weak low in the west-central to SW Caribbean next Wed-Thu. The low appears to develop along the trailing end of an old frontal boundary, combined with a little moisture from a westward-moving tropical wave that's now well east of the Caribbean. This is a quite common setup for late-season development, so I wouldn't be too quick to discount the possibility. But given how unfavorable the Caribbean Sea has been for TCs this season, I wouldn't expect more than a TD or weak TS while it's in the Caribbean.

Moderate to strong WNW-NW winds across the eastern Gulf and Florida should keep any development east of the U.S., but I'm not ready to 100% guarantee no grazing impact to SE FL late next week, should something develop down there. However, westerly shear in the region north of Cuba would most likely keep most of the convection east of the track, so that does limit the risk to SE FL.

Caribbean Instability remains quite low compared to normal, meaning the atmosphere is more stable. This is mostly the result of sinking air aloft resulting in a warm layer aloft:

[gatorcane]

Wxman57 yeah I agree with that assessment, chances are this stays south and east of Florida. The only thing I would say is it is difficult to say where the strong shear boundary will lie caused by the westerlies last next week into next weekend. If that boundary sets up a bit north, even over central Florida, it could open the door for a South Florida impact/grazing.

Update on the models. Here is the 00Z FIM model at 240 hours. Like the ECMWF, has shifted west some with it's projected track. The models for the past day or so were trending more east with the track and last night have trended back west some:

[cycloneye]

HPC forecast for day 7.

[Blown Away]

Wxman57 yeah I agree with that assessment, chances are this stays south and east of Florida. The only thing I would say is it is difficult to say where the strong shear boundary will lie caused by the westerlies last next week into next weekend. If that boundary sets up a bit north, even over central Florida, it could open the door for a South Florida impact/grazing.

Update on the models. Here is the 00Z FIM model at 240 hours. Like the ECMWF, has shifted west some with it's projected track. The models for the past day or so were trending more east with the track and last night have trended back west some:

[img]http://imageshack.us/a/img829/7227/00zfim1018.jpg[/img

Over past 100 years, I'm sure that nearly all the late season systems that grazed or just missed SFL, the issue was where that strong shear boundary sets up! Models initially had a system grazing SFL, then moved a little east, and now swinging back closer.

[blp]

00Z CMC similar to 00Z Euro. I do see a west trend today.



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[Hurricaneman]

The original low on the 6zGFS takes a track similar to Wilma or dare I say this Charley and anyone in Cuba, Jamaica, Hispaniola and Pureto Rico should monitor this closely, but after that, anyone from the big bend of Florida to the eastern Bahamas need to keep an eye on the progression of this system

[Hurricaneman]

Is it just me or does it seem the last couple of runs of the GFS show this low splitting into 2 areas of low pressure, the 12zGFS seems to be hinting at that just like the 6Zrun

[wxman57]

Is it just me or does it seem the last couple of runs of the GFS show this low splitting into 2 areas of low pressure, the 12zGFS seems to be hinting at that just like the 6Zrun

I've noticed that the 06Z GFS, particularly over the past week, has been VASTLY different from the 00Z run beyond 5 days or so. It looks quite suspicious, and I'd tend to ignore the 06Z GFS runs. I see what you mean about the last run - two systems, one in the Caribbean and one north of Cuba at the same time. Probably not...

[cycloneye]

That is why I prefer to look much more to the 00z and 12z runs as those have much more data from soundings etc than the 06z and 18z.

[gatorcane]

12Z GFS moves it off to the NE into the extreme SE Bahamas / Eastern Cuba / Hispaniola area. No threat to Florida or the U.S. mainland on that run.

The globals all seem to be agreeing on it lifting north then moving off to the NE in the Caribbean. Besides the 06Z GFS run that spun off another system in the NW Caribbean (which seems unrealistic), there have been no runs that threatened Florida for the past couple of days albeit the runs are still in the long-range and subject to change.

[cycloneye]

12z CMC begins the development around 84 hours and tracks over Jamaica.

http://moe.met.fsu.edu/cgi-bin/cmctc2.c ... =Animation

[Hurricane Alexis]

It's better to be in the track forecasted by models this far out as they probably will change.

[gatorcane]

Here is the 240 hour forecast point for the 12Z ECMWF. Has shifted west some again in the track. Looks like a very large, sprawling system and big rainmaker for somebody. Curiously it is splitting the low much like the GFS has been hinting at with the strong low being the low to the west:

[cycloneye]

Another view of the 12z Euro and the pair of systems.

[cycloneye]

12z CMC at 180 hours.

[somethingfunny]

Nicole from 2010 might be a pretty good analog for what this system might look like based on the models I've seen: