Global Model Runs for W.Caribbean Early Season Development

[jlauderdal]

GFS likes to overcook early season tropical systems but the setup isn't exactly climo right now. Backdoor front late may in south florida, enuff said. more rain would be good for the sunshine state.

[gatorcane]

GFS likes to overcook early season tropical systems but the setup isn't exactly climo right now. Backdoor front late may in south florida, enuff said. more rain would be good for the sunshine state.

I wouldn't be so sure about that. Backdoor front is in the process of fizzling and in a couple of days it will feel like the front never went through as easterly winds bring in deep moisture from the Atlantic. Water temps plenty warm enough in the Western Carribbean for development all the way up through the GOM.

NWS Miami snippet:

EXTENDED PERIOD...WED THROUGH SUN...MOISTURE GRADUALLY INCREASES
AS THE SOUTHEASTERLY FLOW DEEPENS INCREASING ATMOSPHERIC MOISTURE
PULLED NW FROM THE CARIB. MINIMAL COASTAL ACTIVITY WED BUT BECOMING
SCATTERED CWA-WIDE THU AND INTO THE WEEKEND. MAX/MIN TEMPS INCHING
TOWARD MORE NORMAL

Much anticipated moisture returning back into the SW Caribbean:

[Meso]

And apart from that it's not only the GFS showing something,and I think the NAM and CMC have it stronger than the GFS as well.And as gatorcane said the front is dying out and convection is beginning to fire a bit in the S.W,moisture gradually building.Main thing would be the shear,which is likely to lessen as the front decays.I think after 72 hours the shear lessons a bit in the central caribbean

[Eyewall]

997Ml storm hitting florida that is very strong for this time of year.

[cycloneye]

Loop of EPAC and SW Caribbean



You can see how things are moving in the area of the EPAC and the SW Caribbean.It looks like moistere is increasing in the SW Caribbean.

[HURAKAN]

The scenario sounds a lot like Arlene, 1981.

[Eyewall]

I noticed this morning alot of the modles are showing a stronger storm. And if the environment is favorable enough that is not out of the question.

[cycloneye]

The scenario sounds a lot like Arlene, 1981.

That is correct:

http://www.nhc.noaa.gov/archive/storm_w ... elim01.gif

[wobblehead]

From the NWS Mobile, Al: "WE HAVE BEEN EYEING THE PAST SEVERAL RUNS OF THE GFS AND ECMWF WHICH
BRING A STRENGTHENING BAROTROPIC LOW OR OPEN WAVE INTO THE WESTERN
CARIBBEAN NORTH OF THE YUCATAN PENINSULA THIS WEEKEND. HPC LONG
RANGE DISCUSSIONS ALSO INDICATING CLOSE SCRUTINY THEREWITH. MODELS
BUILDING AFOREMENTIONED WAVENUMBER 5 UPPER LEVEL RIDGING WITH LOW
WIND SHEAR OVER CENTRAL AMERICA/WESTERN CARIBBEAN. POSITION OF FEATURE
ON HPC PROG CHARTS ARE STATED TO BE A MODEL AND ENSEMBLE OF
LOCATIONAL AND PRESSURE AVERAGES. THERE SEEMS TO BE AN EQUAL CHANCE
THIS COULD EVOLVE INTO A TUTT FEATURE...AS THERE IS A LOW SHOWN AT
500 MB DIRECTLY OVER THE SURFACE FEATURE THIS WEEKEND. ALL SAID...IS
STILL UNCERTAIN AT THE MOMENT. 77/DALY"

[Vortex]

Link to Arlene

http://www.stormpulse.com/198101

[gatorcane]

1981 tracks showing Arlene in the Western Caribbean.

[cycloneye]

Closer view of Centralamerica.

[Vortex]

cycloneye,

Nice addition. Those graphics will prove handy the next few days.

[Eyewall]

From Dr. Masters blog. In the latest runs we now have three modles GFS NOGAPS and CMC are forecasting a significant tropical cyclone hitting south Florida by the first week in June. Even though the track could always change this is the highest model consensus we have had to this date with this potential system. For the first time I will place in my tropical discussion that there will be a western caribbean strom by week's end when I update it later today.

[Ed Mahmoud]

UK Met runs up to weakening as it approaches land near Tehuanepec, but still in East Pac through 5 days.

414

WTNT80 EGRR 260539



MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC



AND ATLANTIC



GLOBAL MODEL DATA TIME 00UTC 26.05.2008



NEW TROPICAL STORM FORECAST TO DEVELOP AFTER 24 HOURS

FORECAST POSITION AT T+ 24 : 9.1N 92.5W



VERIFYING TIME POSITION STRENGTH TENDENCY

-------------- -------- -------- --------

00UTC 27.05.2008 9.1N 92.5W WEAK

12UTC 27.05.2008 9.3N 89.8W WEAK INTENSIFYING SLIGHTLY

00UTC 28.05.2008 10.6N 89.2W MODERATE INTENSIFYING RAPIDLY

12UTC 28.05.2008 10.7N 90.1W MODERATE LITTLE CHANGE

00UTC 29.05.2008 11.1N 91.0W STRONG INTENSIFYING RAPIDLY

12UTC 29.05.2008 11.4N 92.1W INTENSE INTENSIFYING RAPIDLY

00UTC 30.05.2008 12.2N 92.6W INTENSE INTENSIFYING RAPIDLY

12UTC 30.05.2008 13.4N 92.6W INTENSE LITTLE CHANGE

00UTC 31.05.2008 14.4N 93.2W STRONG WEAKENING RAPIDLY

12UTC 31.05.2008 14.5N 94.2W MODERATE WEAKENING RAPIDLY

00UTC 01.06.2008 14.8N 94.3W WEAK WEAKENING SLIGHTLY





THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE

RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS

AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT





MET OFFICE, EXETER, UK



TOO 260539



[Ed Mahmoud]

Relevant snip of Pacific Tropical Weather Discussion from TPC. Tropical Weather Outlook, BTW, just says nothing expected through 48 hours.

UPPER LEVEL MOISTURE REMAINS CONFINED TO THE SRN PORTION OF THE
AREA...OR S OF THE UPPER ANTICYCLONES AND E OF 122W DUE TO THE
EFFECTS OF UPPER LEVEL DIFFLUENCE RESULTING FROM THE POSITIONS
OF THE ANTICYCLONES RELATIVE TO ONE ANOTHER. THIS MOISTURE IS
PRIMARILY TIED TO CONVECTION DESCRIBED ABOVE UNDER ITCZ. THERE
IS SOME INDICATION...AS SEEN ON WATER VAPOR IMAGERY...THAT THE
NRN FRINGE OF THIS MOISTURE IS WORKING ITSELF NWD IN BETWEEN THE
ANTICYCLONES WITH TIME. RECENT AND CURRENT PRES ANALYSES REVEAL
THAT THIS MOISTURE IS RELATED TO AN AREA OF BROAD LOW PRES
WHICH COVERS THE FAR ERN PACIFIC FROM 03N-14N BETWEEN 84W-100W.
COMPUTER MODELS SUGGEST THAT THIS AREA MAY EVENTUALLY CONSOLIDATE
TO FORM A SPECIFIC LOW CENTER DURING THE NEXT FEW DAYS WITH AN
EVENTUAL TRACK TO THE NE AND N. FOR THE TIME BEING...BOTH
SCATTEROMETER DATA AND A FEW SHIP OBSERVATIONS HAVE SHOWN WINDS
IN THE 20-25 KT RANGE WITH DIRECTION FROM SW TO NW WITHIN THIS
AREA. WILL AWAIT FUTURE MODEL RUNS FOR BETTER CONSISTENCY WITH
RESPECT TO POSSIBLE TIMING AND LOCATION OF A LOW PRES SYSTEM IN
THE FAR ERN PACIFIC OCEAN.

[cycloneye]

NAM model has a pretty strong EPAC system,while it shows something weak in the Western Caribbean.

[HURAKAN]

The wait game begins!!!

[Thunder44]

From Dr. Masters blog. In the latest runs we now have three modles GFS NOGAPS and CMC are forecasting a significant tropical cyclone hitting south Florida by the first week in June. Even though the track could always change this is the highest model consensus we have had to this date with this potential system. For the first time I will place in my tropical discussion that there will be a western caribbean strom by week's end when I update it later today.

This is the discussion he posted on this system this morning:

Possible development in the Western Caribbean or Eastern Pacific late this week
For the past 3-6 days, our most reliable global computer weather forecast models have been predicting the development of a low pressure system near or over Central America by Friday of this week. Given the persistence in the models in developing this low, we need to be alert to the possibility of a tropical depression forming in either the Western Caribbean or Eastern Pacific, on either side of Costa Rica and Nicaragua. It is uncertain which ocean basin such a storm might form in, and whether or not there will be a tropical wave around to help kick off development. It may be that the low pressure region will stay anchored over land south of the Yucatan Peninsula, preventing any development. This is the solution preferred by the ECMWF model in its last few runs. However, the GFS, NOGAPS, and Canadian models all predict a tropical depression might form in the Western Caribbean near Mexico's Yucatan Peninsula. In contrast, the UKMET shows development in the Eastern Pacific, on the Pacific side of Central America. Climatologically, May tropical storms are much more common in the Eastern Pacific than the Western Caribbean, so we should not discount the UKMET solution, even though it is an outlier. All five models predict that the Central American low pressure area will move northward towards the Gulf of Mexico, and wind shear may fall enough to allow a tropical depression to form should the low's center emerge over water. I'll be posting daily updates on the situation this week.

Jeff Masters

[boca]

A watched pot never boils unless your looking at the tropics.