Thoughts on Carib

[Derek Ortt]

The Carib system looks slightly better organized this morning, though it is showing no signs of consolidation, nor is it showig much in the way of banding quite yet. If there is an LLC, it is probably down near 10N and 80W, slightly south of the deepest of the convection. That being said, upper winds are favorable for further development.

Future movement may be a bit tricky since we have nice model divergence. CMC wants to bring the system to the north, across eastern Cuba, then the Bahamas, while NOGAPS keeps this in the Carib for 6 days. Probably, if this system forms faster than expected, CMC may be more likely to verify.

Best bet is to watch this system. No need for anything resembling a panick yet. Could we get something? sure. However, a TD or a TS should not be enough to bring significant excitement.

[wxman57]

My thoughts, followed by the latest plot of sfc obs:'

Satellite and surface observations indicate that a weak area of low pressure is located about 500 miles south of Jamaica near 11.5N/80W. Thunderstorm activity in the region has become a little better organized overnight, but I do not see any evidence of a well-defined low-level circulation center. With weak steering currents aloft, I am not expecting very much movement over the next 3-4 days. Upper-level winds appear to be favorable for tropical development, so I'll be monitoring this strong disturbance beyond the end of hurricane season, which would normally end today.

A number of computer models have consistently indicated that this disturbance will become better organized by the middle to end of this week, possibly becoming a tropical depression or a tropical storm. While I'm not certain that such development will occur, I do think that tropical development is possible as long as the squalls remain stationary over water south of Jamaica. As for future movement, I don't see much to move the disturbance through the middle of the week. But by Thursday, an approaching frontal system to the north may impart a slow northeastward movement on the disturbance. This could bring heavy squalls and gusty wind across the Dominican Republic, eastward across Puerto Rico and the Virgin Islands by next weekend, regardless of whether or not this disturbance becomes a depression or a storm. Beyond next weekend, the system should track out to sea into the Atlantic. It will not threaten the Gulf of Mexico or the U.S. mainland.

Here's the 12Z plot of ship and land stations. There were no offshore reports since 12Z, so that's why I didn't capture a 15-16Z plot. There appears to be a weak low near the coast of Panama, south of the main convection. Minimum pressure is around 1008mb. Note that the 25-30 kt NE winds across the NW Caribbean are post-frontal winds, they're not associated with any developing low.

<img src="http://home.houston.rr.com/wx/disturb.gif">

And here's the latest visible image of the region:

<img src="http://home.houston.rr.com/wx/disturb2.gif">

[Derek Ortt]

Looking at latest visible imagery, it looks like a low center may be trying to develop, about where you placed the low in your plot. Also, we may be seeing some consolidation. If these trends continue, we could see a TD in 24 to 36, but before going wiht that, I'd like to see about 12 to 24 hours of more persistence

[george_r_1961]

In my opinion this system we see down there is primarily frontal in nature..possibly hybrid. While it isnt tropical it has the potential to develop into a whopper of a storm nonetheless as it tracks NE south of FL and imto the open Atlantic. Could get interesting.

[rainstorm]

looks like a ts in the making to me

[WXBUFFJIM]

Some maybe looking at this system as tropical. However it's not impossible that this is a hybrid or possibly hooked onto a frontal boundary. I don't think it's a tropical storm yet and it maybe not too purely tropical either. But with November 30th being the last day of hurricane season in the Atlantic, chances for tropical development are rare anyway. Still an interesting system and possibly a rare December storm.

But it's getting pretty late.

Jim

[Derek Ortt]

The carib system looks nothing like a frontal system at the present time. It is consolidating as many tropical cyclones have in this region late in the season

[wxman57]

This is definitely not a frontal-type low at this time. It's purely tropical. Now there is a cold front to its northwest spilling some slightly cooler and drier air into the western and central Caribbean, but the disturbance is not associated with the front. The latest (11Z this morning) QuickSCAT shows no evidence of an LLC:

http://manati.wwb.noaa.gov/dataimages21 ... MBas20.png

Latest sfc analysis with ship reports (18Z) shows ENE-E winds 30kts between 13N-15N near 80W north of a weak area of low pressure. There is no clear rotation center in the lower levels, however:

<img src="http://home.houston.rr.com/wx/disturb4.gif">

Looking at the latest satellite, I can see evidence of good outflow in all quadrants - indicating an upper-level high is over the system (more evidence that this is not a subtropical or hybrid low):

<img src="http://home.houston.rr.com/wx/disturb3.gif">

[cycloneye]

It will be a slow proccess in terms of development of this system but it has all the ingredients to be a cyclone later this week and be a threat of more rain for PR even if it tracks west of the island in the mona channel due to the moistere it will send up from the south.we have to watch what track it will take because depending on it PR will see another rain event as earlier this month and we dont need more.