Strong Wave east of Windward islands

[leanne_uk]

yeh baby we got our yellow
Pretty happy the SAL is not going to interfere with the development of this system too

[wxman57]

No, SAL won't be a factor. All this one will have to contend with is 20-30 kts of shear that will tend to only increase as it enters the Caribbean. Take a look at the Canadian run - it doesn't see any shear in the Caribbean, thus it develops a low. The Euro just moves the wave across the Caribbean - no closed low. No closed low, just a wave in the latest GFS run. Development chances look slim. But I agree, it's the only feature in the Atlantic with at least a slight chance of development in the short term.

[cycloneye]

If this is correct,then the shear should relax in the next few days.Lets see if this run of lower shear pans out or not.

http://www.meteo.psu.edu/~gadomski/COMP ... ploop.html

[gatorcane]

No, SAL won't be a factor. All this one will have to contend with is 20-30 kts of shear that will tend to only increase as it enters the Caribbean. Take a look at the Canadian run - it doesn't see any shear in the Caribbean, thus it develops a low. The Euro just moves the wave across the Caribbean - no closed low. No closed low, just a wave in the latest GFS run. Development chances look slim. But I agree, it's the only feature in the Atlantic with at least a slight chance of development in the short term.

Wxman should that shear let up then this one has quite a bit of potential. In fact I have seen a few shear maps from some members that show shear may just be relaxing by the time this wave gets into the Caribbean. We have a low lattitude Cape Verde Wave that looks to be headed towards the Caribbean without recurving east like everything else has this year.

Who would have thought it would have taken until early October to see what you would typically see in August or September.

[cycloneye]

Convection on the increase, starting to look invest worthy. Still lots of shear in its path, but GFS (which has not done a very good job of forecasting shear lately) shows shear decreasing somewhat during the next 48 hours, for whatever that is worth. If the shear decreases, this could be a player.

They will wait to see persistance and to see if a more defined LLC evolves to then have 91L.But if you ask me,invest status is not far away.

[jinftl]

Looking potentially 'interesting'....as does the prospect for environmental conditions becoming more favorable for some development down the road

[gatorcane]

Here is the 06Z GFS Zonal shear animation, which shows shear is decreasing in the area this wave is headed for:

http://moe.met.fsu.edu/cgi-bin/gfstc2.c ... =Animation

[jinftl]

Some evidence of outflow and 'feathering' at the fringes.....these are things we look for in possible contenders for development. Not a tiny system either.

Does this look like a recurve candidate or do we finally have a potential system (ranging from a tropical wave to something more) heading into the Caribbean Sea? I know that NWS Miami is talking about nothing about ridging setting in through the end of the week at least.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
351 AM EDT SUN OCT 4 2009

.DISCUSSION...
HIGH PRESSURE WILL DOMINATE THE REGION FOR THE SHORT TERM AND
LIKELY THROUGH THE LONG TERM AS WELL. AN UPPER LEVEL RIDGE WILL
PERSIST ACROSS THE REGION FOR THE NEXT SEVERAL DAYS...WHILE A
SURFACE AND LOW LEVEL RIDGE WILL BEGIN TO BUILD WESTWARD ACROSS
THE WESTERN ATLANTIC AND ACROSS THE REGION STARTING TODAY AND IS
FORECAST TO BUILD INTO THE EASTERN GULF BY MONDAY. IN FACT BOTH
THE UPPER LEVEL RIDGE AND THE SURFACE AND LOW LEVEL RIDGE ARE
FORECAST TO PERSIST THROUGH AT LEAST FRIDAY

[gatorcane]

To check when it becomes an invest, here is the page. Could be an invest later today.

http://www.nrlmry.navy.mil/tc_pages/tc_home.html

[Blown Away]

CMC still developing this wave into a weak system and moves through the Caribbean. CMC seems to develop this wave more when it reaches the W Caribbean. The CMC end run in 6 days is near 80W and hints a turn to the NW towards Cuba. Lots of shear on the way and the CMC has this wave moving 2400 miles in 6 days. Who knows, maybe a potential Cuba, EGOM, or Florida system, likely not but something to watch.

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

[Sanibel]

If you look at what we have seen of 2009 so far this shouldn't develop. However it does have the look of a slow-cooking tropical trough that tends to gell and form in October. So if 2009 holds true it won't develop, but if it does it is because of the tendency of this area to spin up such waves at this time if they enter the Caribbean. The wave is too late for this area but not for further west.

[Blown Away]

Seems there will be a decent ridge for the next few days and this wave should move through the Caribbean. I wouldn't be surprised to see 1 more system before the end and IMO it will occur in the W Caribbean or N Atlantic.

[gatorcane]

If you look at what we have seen of 2009 so far this shouldn't develop. However it does have the look of a slow-cooking tropical trough that tends to gell and form in October. So if 2009 holds true it won't develop, but if it does it is because of the tendency of this area to spin up such waves at this time if they enter the Caribbean. The wave is too late for this area but not for further west.

Not too late for this area if conditions are right. NHC seems to think slow development is possible and I do also.

Despite the upper-levels being unfavorable for the past month or more, when I look out at the lower-levels in the Atlantic I see a very summer-time setup out there with several waves still marching across the basin. Even closer to home, NWS Miami notes the possibility of records highs across South FL later this week with deep H5 layer ridging for most of the week, telling me summer-time rolls onward still even October.

I also see some signs the upper-levels may finally become more favorable across the Caribbean and Western Atlantic. The 40 day Chi also shows less sinking air across the basin by mid October.

[cycloneye]

Here is what Dr Jeff Masters has to say about this wave.

A large tropical wave near 9N 40W, midway between Africa and the Lesser Antilles Islands, is generating a considerable amount of heavy thunderstorm activity as it moves west to west-northwest at 15 mph. The wave is under about 10 - 15 knots of wind shear, and this morning's QuikSCAT pass showed a large and disorganized region of converging winds in the region, with top winds of 25 mph. There is very little dry air in the vicinity, and conditions appear favorable for some slow development of this wave. None of the computer models develop the wave, but they do show relatively low wind shear along the wave's path for the next five days. The wave should reach the Lesser Antilles Islands by Wednesday.

[BigA]

I wouldn't say that none of the models show development. The CMC and WRF seem to show a tropical cyclone forming from this area.

In any case, one of the students in my college's study abroad program in Peru is named Grace, and she is hoping that we can squeeze one more storm out of this season.

[jinftl]

I have maintained this all season....tchp is even higher than it usually is across the western caribbean (esp in the area between the yucatan, cuba, and cayman islands). Shear is forecast to drop in the next 72 hours even. History has shown that explosive development can occur late into october in that very region (i.e., mitch, wilma).....let's hope that a system doesn't find its way to that powder keg.

This image is 2 weeks old...but has been consistent all season.....tchp is higher than it has been in the last few years in the nw caribbean....




Shear is forecast to drop, in as soon as 72 hours....with ridging setting in this week in the western atlantic....pushing any system more west than north



What we look for in potential development is the factors aligning that would promote it.....too soon to say for sure, but this system bears watching for sure as some of the broader factors appear to 'want' to align. There is no rule that a system can't still sneak into the picture this late, even in a slow season, if the factors suddenly align for it.

[wxman57]

Slim shot at developing. Very disorganized, and I think shear will be higher in advance of it than models may be depicting. Not concerned about development as long as it lacks a core of heavy convection.

[Gustywind]

From the Weather Channel http://www.weather.com/newscenter/tropical/
Atlantic wave, w. Pacific Super Typhoon
Kevin Roth, Lead Meteorologist, The Weather Channel
Oct. 4, 2009 10:24 am ET

There is a small area of low pressure along the southern end of a tropical wave around 8N and 40W moving to the west-northwest at 15 to 20 mph. A large area of shower and thunderstorm activity accompanies the wave and low. Environment conditions are marginally favorable for some slow development of this system over the next few days. We will monitor the system for any further strengthening.

[cycloneye]

Vorticity at 850 mb is good.

[jinftl]

Stepping back from the season we have seen.....speaking purely from an untrained eye looking at a satellite image....this is interesting looking, bordering on 'impressive'. The 'slow development is possible' jargon is certainly a change from weeks of 'no development is expected' basin-wide. Conditions do change...even in seasons like this...if only for a few days here and there. Timing is everything...along with location.