Early June Development in WCarib or BOC? (Is Invest 91L)

[Hurricaneman]

I think its phony storms are caused by MJO feedback, when the wet phase comes in it causes convective feedback issues

[TropicalAnalystwx13]

Pre/early season tropical storms are uncommon in-themselves, but the upcoming pattern gives us practically the highest chance of having a tropical cyclone near the beginning of the hurricane season that one can get. MJO pulse in the region, high pressure north of the Caribbean, etc.

All major models have something now. CMC and GFS have tropical cyclones, ECMWF has lower-than-average pressure.

Doubt it's convective feedback. As I said a while back (though my timeline was off ), models typically show development, drop it for a few days, and then pick it back up.

[TropicalAnalystwx13]

wouldnt trust the ECMWF for genesis in the deep tropics. It failed big time with Mahasen

It was dead on with predicting no significant intensification with first tc in epac.

That's because it never showed the tropical cyclone in the eastern Pacific. The ECMWF's main problem is failure to develop and intensify a system. It has a great hold on the synoptic pattern, however.

[Alyono]

wouldnt trust the ECMWF for genesis in the deep tropics. It failed big time with Mahasen

It was dead on with predicting no significant intensification with first tc in epac.

That's because it never showed the tropical cyclone in the eastern Pacific. The ECMWF's main problem is failure to develop and intensify a system. It has a great hold on the synoptic pattern, however.

the EC can intensify a TC just fine. In fact, it often overdoes intensification of a well formed TC.

I wonder if the issue is actually the high resolution of the ECMWF. It may be too fine of a resolution for having parameterized convection, but not fine enough for explicit convection. In a few years, if the EC goes to explicit convection (this will lead to NO CONVECTIVE FEEDBACK), this issue will be resolved

[gatorcane]

12Z FIM model shows a noticeable area of convection and moisture associated with the MJO across the Southwest Caribbean at 240 hours:

[chaser1]

Pre/early season tropical storms are uncommon in-themselves, but the upcoming pattern gives us practically the highest chance of having a tropical cyclone near the beginning of the hurricane season that one can get. MJO pulse in the region, high pressure north of the Caribbean, etc.

All major models have something now. CMC and GFS have tropical cyclones, ECMWF has lower-than-average pressure.

Doubt it's convective feedback. As I said a while back (though my timeline was off ), models typically show development, drop it for a few days, and then pick it back up.

I would potentially agree with the above statement if the synoptic conditions as discussed above were to fall in place as anticipated. Just for the sake of (friendly ) argument however, lets pretend that we were now 72 hr.'s from model verification and suddenly every single model were to drop any hint of development. Lets assume one or two waves are mixed within a densely moist air mass and causing copious amounts of rain throughout the W. Caribbean and the long predicted lowering of surface pressures began to verify. Still though, model run after model run .....continue to no longer indicate any significant cyclonic organization and at 60 hr.'s away (from prior anticipated tropical development) it were plainly obvious from viewing satellite, that "screaming" upper level shear is obviously blowing straight "west to east" at 30-50 knots. I don't think too many of us would likely take a stand "against" most of the reliable models which now no longer forecast any development, right? It's a rhetorical question of course, but most of us realize that there is a fairly good deal of accuracy when under 72 hours, especially after consistent runs and even more when collaborated by all other models as well. "The Point"? YES....there "is a point here" (um, I mean there)

.... and my point pertains to the levels of accuracy that upper level features or conditions (say, from 100mb-350mb) can be accurately predicted beyond 192 hrs.

One of the things I had learned during the many years of model and chart watching, and through many of Max Mayfield's (then Hurricane Forecaster) midnight shifts at NHC (across from UM) where he would sarcastically quip "don't you have a home?" or "did you bring a pillow?"......, was that long range models - especially at 7-10 days are far less likely to accurately predict upper level conditions than perhaps their ability to sniff out lower level deviations in large scale pressure changes or fairly large dominant surface features. So, while I do tend to join the camp of those anticipating lowering pressures and a significant surge in moisture that models are picking up on (in conjunction with the MJO), I would also straddle the side of the fence, leaning toward tropical genesis if ummm, there were a fat lazy anticyclone sitting over Central America right now? I mean, c'mon.... climatology is my friend. On the other hand though, "persistence" is my mentor! So, in light of persistent upper level westerly winds throughout the Caribbean, its just a little hard for me to have much taste for the 10 day kool-aid that any long range model might presently be pouring. If and when the shear abates, then heck....my floating bandwagon will be firmly anchored to Bouy Station 42056 (somewhere East of Cozumel) and waiting for the 6 mb pressure drop as well!

[beoumont]

As noted in the above post, tropical cyclone genesis only happens when a coincidence of conditions come together at the same time in the same place: diffluence at the upper levels, convergence at the lower levels, adequate moisture at all levels, warm enough temps. on the surface and ocean surface, and warm enough temps. at mid levels (5 or 6 degrees celcius or warmer at 500 mb)., and relatively low pressures near the surface.

But even when those conditions all are present, you still need to have a pre-existent disturbance come into that area; as well: an easterly wave, a surface low that has broken off from the westerlies, etc. Luck / magic. It takes a village; over open water.

[psyclone]

This has been a classic, pre season "jump the gun" thread on a board full of weather geeks amped up for another tropical season to begin. the goal posts continue to move. I believe the original title was "late may development likely". Well, unless something is imminent, late May development is never likely. if it were then late May would be part of hurricane season in the Atlantic basin. The only thing that has been and remains an interest to me is the potential for deep tropical moisture to overspread FL and kick off the rainy season a bit earlier than climo. Otherwise it has been, and remains too soon for there to be useful speculation on anything more meaningful.

[Hurricane Jed]

Andrea will form when it wants to form. Not when we want it to form.

[TropicalAnalystwx13]

All but 2 of the 00z and 06z GFS ensembles combined show potent tropical cyclone development in the western Atlantic (some develop it in the Caribbean, some show the low in the Caribbean but don't develop it until the Bahamas) *by* June 1 (and that's being conservative...a lot of the members develop a cyclone a few days before that).

[beoumont]

This has been a classic, pre season "jump the gun" thread on a board full of weather geeks amped up for another tropical season to begin. the goal posts continue to move. I believe the original title was "late may development likely". Well, unless something is imminent, late May development is never likely. if it were then late May would be part of hurricane season in the Atlantic basin. The only thing that has been and remains an interest to me is the potential for deep tropical moisture to overspread FL and kick off the rainy season a bit earlier than climo. Otherwise it has been, and remains too soon for there to be useful speculation on anything more meaningful.

From the great Wikipedia, but accurate to the best of my recollection:

The basic concept of a hurricane season began during 1935, when dedicated wire circuits known as hurricane circuits began to be set up along the Gulf and Atlantic coasts, a process completed by 1955. It was originally the time frame when the tropics were monitored routinely for tropical cyclone activity, and was originally defined as from June 15 through October 31. Over the years, the beginning date was shifted back to June 1, while the end date was shifted to November 15,before settling at November 30 by 1965. This was when hurricane reconnaissance planes were sent out to fly across the Atlantic and Gulf of Mexico on a routine basis to look for potential tropical cyclones, in the years prior to the continuous weather satellite era. After regular satellite surveillance began, hurricane hunter aircraft flew only into areas which were spotted first by satellite imagery.


I'll personally add that the eventually settling on an exactly 6 month long season has some basis in personnel allotment planning and Congressional budget requests made easier for the NWS.

[chaser1]

This has been a classic, pre season "jump the gun" thread on a board full of weather geeks amped up for another tropical season to begin. the goal posts continue to move. I believe the original title was "late may development likely". Well, unless something is imminent, late May development is never likely. if it were then late May would be part of hurricane season in the Atlantic basin. The only thing that has been and remains an interest to me is the potential for deep tropical moisture to overspread FL and kick off the rainy season a bit earlier than climo. Otherwise it has been, and remains too soon for there to be useful speculation on anything more meaningful.

This could be a classic pre-season "jumping of the gun" and I agree with all of those points made in posts above ( ).

Having said that, I certainly don't claim to have the forecasting skill to know that I am right either. My only point with regards to this - Late May/Early June Development in Western Caribbean - thread, is that our own enthusiasm should be moderated by as much science as possible (and yes, long range models are at least a part of that science too). On the other hand, I sure am thrilled that this or other forums exist for "this" weather geek (meaning me ), because I am one of those who is also "amped up" for another Atlantic hurricane season to begin. I know one thing, this site (and thread) makes the Hurricane season far more engaging to me.

So, regardless of climatology, the MJO, GFS upgrades, which is more accurate - the CMC or Farmers Almanac (thats a tough one), or who here might be right or wrong regarding when/where a TC might form.... I think that tolerance, willingness to both teach & learn, & maybe even a slight sense of humor might continue to go a long way for everyone regardless one's own interest & motivation for posting (or lurking) here. And at the risk of sounding like a cheerleader, I say KUDOS to S2K for simply being the site that it is & where I likely spend more time than I should (well, at least close too & during the hurricane season LOL). That is why some weeks ago when I read how this site might be in danger of maintaining its own costs to continue to operate, I was thrilled to make a voluntary paypal contribution to this site. I've never done that before and I have no clue "who" or how many run or own it & do not care. I would MUCH RATHER overlook what some call "wish-casting" or less corroborated speculation, than be part of some tightly moderated thread with inane post policies and forum moderation. Been there -done that, and for me who years ago had looked for a tropical weather forum where others could openly share info, observations and opposing opinion (and without consistent scrutiny & correction) that prior experience of mine simply represents a website/forum that chooses to not encourage such banter & dialogue.

Hmmmmmm, 12Z GFS 384 hr. shows an interesting 1006 low associated with the ITCZ soon to emerge from the African coast........

[Hurricaneman]

The 18zGFS shows the low again forming between 192 and 204 hrs but doesn't develop it much and buries it into Belieze into Mexico

[blp]

12z Euro has a low off of Belize and a low in the EPac which coincides with the 06z GFS. Not much at the moment but at least there is a similarity. Interested to see the next few euro runs.

12z euro
http://raleighwx.americanwx.com/models/ ... SLP240.gif

06z GFS
http://raleighwx.americanwx.com/models/ ... SLP240.gif

[Hurricaneman]

12z Euro has a low off of Belize and a low in the EPac which coincides with the 06z GFS. Not much at the moment but at least there is a similarity. Interested to see the next few euro runs.

12z euro
http://raleighwx.americanwx.com/models/ ... SLP240.gif

06z GFS
http://raleighwx.americanwx.com/models/ ... SLP240.gif

Makes one think that something may indeed form near Belieze whether it be a tropical system or broad low some time next week or at the very least a major increase in moisture

[NDG]

GFS is still fairly persistent in tropical development in the western Caribbean.
It shows first development to start in the EPAC close to the Costa Rican coast by the end of the week and for it to track close to the C.A. Pacific coast towards Guatemala/southern MX, die out and for a new disturbance to form on the Caribbean side of C.A. next week.

[cycloneye]

GFS is still fairly persistent in tropical development in the western Caribbean.
It shows first development to start in the EPAC close to the Costa Rican coast by the end of the week and for it to track close to the C.A. Pacific coast towards Guatemala/southern MX, die out and for a new disturbance to form on the Caribbean side of C.A. next week.

This wave in Eastern Atlantic may provide energy to the area. We will see what occurs down the road.

[Aric Dunn]

12z cmc...

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


12z euro monsoon trough in central western carrib and a system in eastern pacific.

safe to say area will need to be watched as that time frame approaches

http://www.meteo.psu.edu/~fxg1/ECMWFTRO ... floop.html

gfs much earlier on development in eastern pacific... could be that it develops in western carrib instead


http://mag.ncep.noaa.gov/list_files_are ... wnd_precip

[SouthFloridawx]

Also need to watch the timing of approaching fronts dipping into the GOM.

[NDG]

Current CPC's MJO update:

•The MJO became less coherent during the past week as the enhanced phase advanced east of the Maritime Continent.
•Dynamical model MJO index forecasts are in good agreement for a generally weak MJO signal during Week-1, in part related to interference from other tropical subseasonal variability, but also from a weakened MJO. The models indicate potential renewed organization of an enhanced phase across the Western Hemisphere and Africa during Week-2.
•Based on recent observations and model MJO forecasts, the MJO is forecast to become better organized during Week-2 with the enhanced phase centered across the Western Hemisphere and Africa.
•Enhanced (suppressed) rainfall is favored across the east Pacific / Central America (west Africa / Indian Ocean / Philippines) primarily associated with other subseasonal variability. Elevated chances for tropical cyclone development exist across the eastern Pacific Ocean.
•A more organized MJO favors enhanced rainfall across central America and the western Caribbean Sea during Week-2 where tropical cyclogenesis chances are also elevated. Above average rainfall is also favored for west Africa, the Indian Ocean and southern India while below average rainfall is most likely for the Philippines and parts of the western Pacific Ocean.

http://www.cpc.ncep.noaa.gov/products/p ... update.pdf