ATL: TROPICAL DEPRESSION ALEX - DISCUSSION

[littlevince]

Storms that formed in the Caribbean in June

[Comanche]

I feel this system will wind up eventually being our first named of the year. From everything I have gathered thusfar, conditions will likely improve in the coming days as it moves further west. The heat potential and low shear environment in the gulf makes this more like late July than late June. I am going out on a limb and saying this winds up a cat 1 into the northern Mex/Southern Tex area next week.

I am not a meteorologist, not do I play one on tv, so whatever I say is purely speculative on my part!

[Frank2]

If by downcasting you mean to make less than, it's not that - over the years (I've been here more than 5) we've found that opportunistic media and oil speculators do lurk here - and often use panicked "It's coming this way!" comments to their advantage (and to everyone else's disadvantage), so it's important for those of us with any meteorological background (while not a met I did work with them for a number of years as a tech), to help assure those new here (the market speculators and media included) that there are valid meteorological reasons for a system not developing...

On the other hand, if the outlook does look grim, then it's important that the reality of the situation not be ignored or downplayed - but we are a very long way from that in this case...

Frank

[cycloneye]

The latest.

[SoupBone]

Can the moderators PLEASE start removing the "downcasting" from this topic?


I am getting quickly tired of seeing it.

What are your examples of downcasting? So far all I've seen are peoples opinions which may vary from yours.

[Aric Dunn]

Storms that formed in the Caribbean in June

hey thanks notice no development at all in central and eastern carrib... couple tracks through it but they developed before carrib
can you do it for the rest of the months..

[Aquawind]

Well Said Aric.. The graphic tells us how rare formation is in 93L's current location.. Thanks littlevince!

[Frank2]

So far all I've seen are peoples opinions which may vary from yours.

Well said - it is a message board, after all...

[cycloneye]

The northern extent of 93L looks like is creeping northward towards Puerto Rico. Yeah,we dont need more rain now after what ex 92L brought last weekend.

[littlevince]

hey thanks notice no development at all in central and eastern carrib... couple tracks through it but they developed before carrib
can you do it for the rest of the months..

Image is from NOAA (query by climatology): http://csc-s-maps-q.csc.noaa.gov/hurricanes/viewer.html

[HURAKAN]

Very humid

[Lowpressure]

Looking ahead, conditions seem very favorable for intensification once a LLC becomes established. Intensity models are all over the board, but it seems reasonable we will get a named system by Wednesday. May become an issue for oil cleanup efforts.

[vbhoutex]

Members will notice that there are already some posts disappearing from this thread. They are being removed as they have nothing to do with Invest 93L. Staff will continue to monitor this and all threads for the same type of thing. If you have a problem with how someone is posting PLEASE DO NOT TRY TO DEAL WITH IT BY YOURSELF ON THE OPEN BOARD. That is why we have a staff. Contact one of the staff by pm and we will take it from there. This will help keep the discussions on track about the subject.

[thetruesms]

I haven't taken the time to watch the presentation, but there was one at the AMS conference on "The tropical cyclogenesis 'hole' in the Caribbean"
Unfortunately, there doesn't seem to be a write-up available, just the video of the presentation.

There was also an article in BAMS in February by Shieh and Colucci about the exact same thing. Granted, you need an AMS membership to read it for a while yet, but here's the abstract:

Local Minimum of Tropical Cyclogenesis in the Eastern Caribbean
Owen H. Shieh
School of Meteorology, University of Oklahoma, Norman, Oklahoma

Stephen J. Colucci
Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, New York

Abstract
The study investigates the local climatological minimum of tropical cyclogenesis over the eastern Caribbean Sea. This area, colloquially known by forecasters as the “hurricane graveyard,” is located within the deep tropical easterlies. Tropical disturbances emerging from the African continent usually pass through the Lesser Antilles and into the eastern Caribbean. Satellite imagery shows disturbances that frequently exhibit decreasing convection in an area bounded by the islands to the north and east, Venezuela to the south, and roughly 75°W longitude to the west. Quick Scatterometer (QuikSCAT)-derived surface winds during clear-sky conditions frequently show the presence of accelerating easterlies in the central Caribbean as part of the Caribbean low-level jet (CLLJ). Analysis of the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis project wind fields suggests the presence of an area of persistent low-level mass divergence over the eastern Caribbean. This implies a subsident regime that would weaken convection. Climatologically, this phenomenon reaches peak intensity in July, and then shifts toward the east and weakens during the latter half of the Atlantic hurricane season. This is reflected by the local minimum of tropical cyclogenesis points in the National Hurricane Center's best-track data in the early part of the season. The intensity of the low-level divergence in the eastern Caribbean is shown to be correlated with the Southern Oscillation index. The divergent low-level easterly flow can also enhance the vertical wind shear and help lower sea surface temperatures, further inhibiting tropical cyclogenesis. The local minimum of tropical cyclogenesis in this region has important implications to operational forecasting, because the vast majority of tropical cyclones in the Caribbean eventually affect surrounding landmasses.

http://journals.ametsoc.org/doi/abs/10.1175/2009BAMS2822.1

[Aric Dunn]

I haven't taken the time to watch the presentation, but there was one at the AMS conference on "The tropical cyclogenesis 'hole' in the Caribbean"
Unfortunately, there doesn't seem to be a write-up available, just the video of the presentation.

There was also an article in BAMS in February by Shieh and Colucci about the exact same thing. Granted, you need an AMS membership to read it for a while yet, but here's the abstract:

Local Minimum of Tropical Cyclogenesis in the Eastern Caribbean
Owen H. Shieh
School of Meteorology, University of Oklahoma, Norman, Oklahoma

Stephen J. Colucci
Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, New York

Abstract
The study investigates the local climatological minimum of tropical cyclogenesis over the eastern Caribbean Sea. This area, colloquially known by forecasters as the “hurricane graveyard,” is located within the deep tropical easterlies. Tropical disturbances emerging from the African continent usually pass through the Lesser Antilles and into the eastern Caribbean. Satellite imagery shows disturbances that frequently exhibit decreasing convection in an area bounded by the islands to the north and east, Venezuela to the south, and roughly 75°W longitude to the west. Quick Scatterometer (QuikSCAT)-derived surface winds during clear-sky conditions frequently show the presence of accelerating easterlies in the central Caribbean as part of the Caribbean low-level jet (CLLJ). Analysis of the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis project wind fields suggests the presence of an area of persistent low-level mass divergence over the eastern Caribbean. This implies a subsident regime that would weaken convection. Climatologically, this phenomenon reaches peak intensity in July, and then shifts toward the east and weakens during the latter half of the Atlantic hurricane season. This is reflected by the local minimum of tropical cyclogenesis points in the National Hurricane Center's best-track data in the early part of the season. The intensity of the low-level divergence in the eastern Caribbean is shown to be correlated with the Southern Oscillation index. The divergent low-level easterly flow can also enhance the vertical wind shear and help lower sea surface temperatures, further inhibiting tropical cyclogenesis. The local minimum of tropical cyclogenesis in this region has important implications to operational forecasting, because the vast majority of tropical cyclones in the Caribbean eventually affect surrounding landmasses.

http://journals.ametsoc.org/doi/abs/10.1175/2009BAMS2822.1

Thanks for that I have been looking some sort of article on it.

[Aquawind]

Great posts by vb and true...

[ronjon]

93L appears to be attached to a monsoon trough extending E-SE into the central Atlantic ITCZ.

[HURAKAN]

Interesting that the highest vorticity is located east of 93L

[Weatherfreak000]

93L appears to be attached to a monsoon trough extending E-SE into the central Atlantic ITCZ.

I agree....it appears to be making it difficult for the invest to re-fire that convection. We will have to see how trends go for the rest of the day.

[KWT]

A bit of a convective mess out there as you'd expect given its just an invest.

I think this needs to be watched in the W.Caribbean, I'd think this one will probably end up hitting the Yucatan and possibly then into the N.BoC or SW.GoM where developmental chances are best.

Not sure why the models aren't developing anything out there given it'll have favourable conditions aloft, can't have a good grip on the situation out there IMO...not saying we are going to get huge development, but there is at least enough to suggest a weak system.