Global Model Runs for W.Caribbean Early Season Development

[KWT]

GFS at 96 hours:

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_096m.gif

Solid mid-level ridge across Texas, the Gulf all the way to the Bahamas.

Yep, what will be interesting is if the low can get into the BOC before heading further north into any weakness that will no doubt eventually form.

[Aric Dunn]

Interesting 96hrs Aric...to be at this stage where any center could form the models may not be the best device to use beyond 72hrs simply because it depends on what forms.

As for the rigding issue, that will slowly decay I should think to the east and open a weakness up which will eventually send the system more to the north, may mean a very slack moving system though for a good 2-3 days, maybe overland.

Clearly the worst case for the SE US, especially Florida, is that we get a slack moving system over the open waters of the SW and Western Caribbean for a couple of days allowing this low to deepen and then the low eventually finds a weakness in the ridge to the north which would eventually happen....but its way too uncertain at this time what will happen.

actually the GFS keeps sniffing out a weakness to drive whatever is in the Caribbean north and then eventually NE....I think it is picking up on a new system that will approach the Pacific NW and drive SE possibly eroding the ridge over Texas and the northern GOM.

Right im only mentioning the forecast out that far it still give a general idea of what the synopics may look like at that time ..

[Aric Dunn]

108 hour brings it more north ...

[Aric Dunn]

144 hour ... gfs doing what its been for the last few runs this far out.. it keeps getting stuck? i wonder if its having an issue with the land interaction

[KWT]

Everything becomes messy on this run, the 12z GFS actually slightly redevelops the high again and this forces the system slightly further west towards the other circulation thats trying to form in the EPAC and as a result we get something of a messy set-up occuring by 156hrs with the low that was in the Caribbean opening up somewhat.

[Aric Dunn]

now there is no east pac system and the two have not merged just one died and or both and a new center redevelops ....lol .. im just going to disregard the gfs after the 120 hrs or earlier .. really only up to 72 hrs is ok

180hrs

[KWT]

Yeah it looks like it does re-form a new center of circulation which is interesting, not unheard of for such systems to occur actually though, one to keep an eye on. If the 12z is right we are gonig to get burnt out by this system given it could well have a pretty erratic track.

[Aric Dunn]

12z nogaps is coming now .

[KWT]

Well after a very messy set-up within 180hrs the system finally gets its act together and heads NE/ENE towards Cuba/Florida also getting as good bit stronger again before becoming absorbed by another low around 288hrs.

For now I think in terms of model realiablity we can only go out to 48hrs, maybe 72hrs because of the various circulations within that broad circulation.

[gatorcane]

in other words all we can do is wait and see....and keep the bear watch on it

[KWT]

Pretty much, I think we are just about at the time where its best if we keep a look at real obs and images/loops rather then take the models too seriously.

[Ed Mahmoud]

After intent staring at visible loop, it appears to my untrained eye that there is a weak circulation at some level on the Caribbean side, a better organized circulation on the Pacific side, and a loose circulation over Panama and Nicaragua that the other two circulations may be feeling.

My guess is 90L isn't this week, and 50/50 on 90E.

As an aside...

The Ohio State U. "Twister" text site has been redesigned and ruined, no longer one stop shopping for text model outputs, which wouldn't be available yet anyway without an invest, discussions, forecasts, and aircraft PODs. I could check NHC site, but I don't recall too many missions on Pacific invests, just systems that posed an imminent threat to Mexico. Just checked NHC, they don't even do out of season tasking except for special winter storms.

[gatorcane]

One thing is for sure, this is quite a disturbed area:

[Derek Ortt]

there is recon out of hurricane season just as there is during the season

They just do not issue the TCPOD unless they are actually flying

[KWT]

Yeah I agree with Ed I can see a good few circulations presently within that broad area of lower pressure, must be very hard for any tropical forecaster to call which area, if any of them will actually concentrate and develop.

Certainly is a disturbed area though, nice deep convection present as well.

[HURAKAN]

Possible development in the Western Caribbean or Eastern Pacific late this week
A weak low pressure area has developed in the Eastern Pacific off the coast of Guatemala, near 11N 91W. This low has the potential to develop into a tropical depression by the end of the week, according to the UKMET model. Other models, such as the GFS, Canadian, and ECMWF, foresee that this area of disturbed weather will not have time to develop before moving northwards over Central America by the end of the week, bringing heavy rains to the region. Once over land, this low might move over the waters of the Western Caribbean and allow a tropical depression to form, as predicted by the GFS model. The NOGAPS model, in contrast, predicts that a tropical depression will form in the Western Caribbean south of Cuba, with no development in the Eastern Pacific. Given the persistence of these computer models over the past week in developing something in the region, I'd put the odds of a tropical depression forming within 7 days at about 40% in the Eastern Pacific, and at 20% in the Western Caribbean. There is a lot of wind shear predicted to prevail near or over the Western Caribbean late this week and early next week, reducing the odds that any such development could hold together long enough to affect the U.S. Regardless, residents of Guatemala, El Salvador, Honduras, Belize, and southern Mexico can expect heavy rains and possible flash flooding late this week from this system.

[HURAKAN]

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE MAY 27 2008

UPPER RIDGE PROVIDES GOOD UPPER DIFFLUENCE AND OUTFLOW FOR ITCZ
DEEP CONVECTION E OF 95W BUT LACK OF UPLIFTING MECHANISM
PREVENTS CONTINUITY TO CYCLE. ONLY EXCEPTION TO THIS SCENARIO
IS HEALTHY 1008 MB LOW PRES AT 11N91W. WHILE STILL QUASI-
STATIONARY...LOW PRES IS EXPECTED TO DRIFT INTO FAVORABLE
ENVIRONMENT ALOFT CONDUCIVE TO DEVELOPMENT WITHIN 48 HRS AS
LARGE AREA OF WLY WINDS ON S SIDE OF LOW PRES LIKELY TO BRING
PLENTY OF ADDITIONAL WARM TRPCL MOISTURE INTO SYSTEM.

[HURAKAN]

SHOWER ACTIVITY ASSOCIATED WITH A BROAD AREA OF LOW PRESSURE
CENTERED ABOUT 300 MILES WEST OF COSTA RICA HAS INCREASED SOMEWHAT
IN ORGANIZATION THIS MORNING. SOME SLOW DEVELOPMENT OF THIS
NEARLY-STATIONARY SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF
DAYS...AND THE LOW COULD HELP PRODUCE LOCALLY HEAVY RAINS OVER
PORTIONS OF PANAMA...COSTA RICA AND NICARAGUA OVER THE NEXT DAY OR
TWO.

Alma or Arthur, that is the question!!!

[cycloneye]

Another view of the area of interest.

[KWT]

So they are currently gunning for the development of the EPAC system, I certainly wouldn't be surprised if we see 90E from that area, it does look good in the loops just lacks a little in regards to any sustianed deep convection near the center but you don't really need that to be worthy of an invest, if it carries on looking good expect it maybe sometime today/tonight?

I think TD1 in the EPAC will come 1st, not sure whether either possible development will beocme a tropical storm mind you.