ATL: GASTON - Models

[Wx_Warrior]

Agreed...hasn't performed superb with struggling systems.

[chrisjslucia]

Gaston is a real irritant - he just keeps hanging on in there. UKMet shows him still going on more or less due west into the Caribbean and strengthening a few days out - Wednesday, Thursday and then again Saturday. I suspect Gaston is going to continue bugging the boards throughout the week ahead. Let's hope he never gets worse than irritating...

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC

AND ATLANTIC

GLOBAL MODEL DATA TIME 00UTC 06.09.2010


TROPICAL DEPRESSION GASTON ANALYSED POSITION : 17.2N 52.6W

ATCF IDENTIFIER : AL092010

VERIFYING TIME POSITION STRENGTH TENDENCY

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

00UTC 06.09.2010 17.2N 52.6W WEAK

12UTC 06.09.2010 17.5N 55.5W WEAK LITTLE CHANGE

00UTC 07.09.2010 17.6N 59.2W WEAK LITTLE CHANGE

12UTC 07.09.2010 17.2N 62.7W WEAK LITTLE CHANGE

00UTC 08.09.2010 17.1N 65.6W MODERATE INTENSIFYING SLIGHTLY

12UTC 08.09.2010 17.0N 68.8W MODERATE INTENSIFYING SLIGHTLY

00UTC 09.09.2010 17.2N 70.7W INTENSE INTENSIFYING RAPIDLY

12UTC 09.09.2010 17.4N 73.5W STRONG WEAKENING RAPIDLY

00UTC 10.09.2010 17.6N 74.8W MODERATE LITTLE CHANGE

12UTC 10.09.2010 18.2N 76.7W MODERATE WEAKENING SLIGHTLY

00UTC 11.09.2010 18.5N 78.9W MODERATE INTENSIFYING SLIGHTLY

12UTC 11.09.2010 19.3N 81.1W STRONG INTENSIFYING SLIGHTLY

00UTC 12.09.2010 19.9N 83.5W INTENSE INTENSIFYING SLIGHTLY

[ColinDelia]

I notice the GFS shows decent vorticity at 850 mb but pretty weak at 500 mb. Maybe part of why the GFS refuses to develop Gaston?
I really don't know. Just speculating. Maybe it weakens Gaston once it gets near the islands because it lacking insufficient mid-level structure.
Or maybe it is just the lack of estimated mid-level structure in general (nothing to do with proximity to land?)

[cycloneye]

12z Tropical Models

Code: Select all

KWBC 061211
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1211 UTC MON SEP 6 2010
 
DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.
 
ATLANTIC OBJECTIVE AIDS FOR
 
DISTURBANCE GASTON (AL092010) 20100906 1200 UTC
 
        ...00 HRS...   ...12 HRS...   ...24 HRS. ..   ...36 HRS...
        100906  1200   100907  0000   100907  1200   100908  0000
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    17.4N  55.5W   17.6N  58.4W   17.5N  61.4W   17.6N  64.1W
BAMD    17.4N  55.5W   17.6N  58.6W   17.7N  61.5W   18.0N  64.1W
BAMM    17.4N  55.5W   17.2N  58.2W   16.9N  61.1W   16.9N  63.6W
LBAR    17.4N  55.5W   17.5N  58.5W   17.8N  61.7W   17.8N  64.7W
SHIP        30KTS          32KTS          38KTS          47KTS
DSHP        30KTS          32KTS          38KTS          47KTS
 
        ...48 HRS...   ...72 HRS...   ...96 HRS. ..   ..120 HRS...
        100908  1200   100909  1200   100910  1200   100911  1200
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    17.5N  66.4W   17.5N  70.1W   17.5N  73.2W   17.7N  77.2W
BAMD    18.2N  66.4W   18.5N  69.8W   18.8N  72.6W   19.2N  76.0W
BAMM    16.8N  65.9W   17.0N  69.8W   17.3N  73.1W   17.8N  77.1W
LBAR    17.8N  67.5W   17.8N  71.9W   17.5N  75.3W   14.3N  78.5W
SHIP        58KTS          76KTS          91KTS         112KTS
DSHP        58KTS          76KTS          91KTS         112KTS
 
         ...INITIAL CONDITIONS...
LATCUR =  17.4N LONCUR =  55.5W DIRCUR = 275DEG SPDCUR =  14KT
LATM12 =  17.1N LONM12 =  52.6W DIRM12 = 273DEG SPDM12 =  12KT
LATM24 =  16.9N LONM24 =  50.0W
WNDCUR =   30KT RMAXWD =   75NM WNDM12 =   30KT
CENPRS = 1008MB OUTPRS = 1012MB OUTRAD =  150NM SDEPTH =   S
RD34NE =    0NM RD34SE =    0NM RD34SW =    0NM RD34NW =   0NM
 


[BigA]

Looks like it should stay south of Hispaniola per the model consensus. The intensity model seems to show conditions becoming progressively more favorable soon (It should be noted that for a while it has been showing steady conditions, then conditions becoming more favorable). So, maybe this system will be the exception to the rule that eastern caribbean conditions are generally unfavorable for cyclogenesis.

[chrisjslucia]

Looks like it should stay south of Hispaniola per the model consensus. The intensity model seems to show conditions becoming progressively more favorable soon (It should be noted that for a while it has been showing steady conditions, then conditions becoming more favorable). So, maybe this system will be the exception to the rule that eastern caribbean conditions are generally unfavorable for cyclogenesis.

I think that Gaston as an exception to the rule may be a good description to adopt given the heat it has generated on the boards

[KWT]

Pretty much all models don't redevelop this one now so looking likely Gaston's first session as a TS is all we are going to see from it...

[Macrocane]

The models are trending a little more to the south, if that trend continues it will end making landfall in Central America or Yucatan, several countries may be affected, so even if Gaston is still struggling it really bears watching IMO.

[rockyman]

Pretty much all models don't redevelop this one now so looking likely Gaston's first session as a TS is all we are going to see from it...

NHC isn't convinced by the models...since we're still at Code Red

[KWT]

Well they gotta keep Code Red just in case, no reason why it can't become a depression but the models really don't go beyond that bad and if you look at the models most have done well with this system so far with no major redevelopment.

[gatorcane]

I can argue the nhc has been wrong on this system so far and the globals have been correct. It's been at a high chance of development for over 3 days now! Best to have kept it a low chance probably around 30 or 40%. Sometimes you wonder if they are putting too much weight on the gfdl and hwrf. To be honest I think I was also.

[Ivanhater]

I would caution not to put all your eggs in one basket concerning some models not redeveloping this. Remember these are the same models that never saw Gaston developing to begin with.

It is September in peak season with a nice LLC about to traverse the warm Caribbean waters. If I were a betting man, I would be in the redevelopment camp.

[ROCK]

still in the redevelopment camp here....though I dont know why the GFS is still not doing anything with it...maybe land interaction....

[clfenwi]

18Z Tropical suite. SHIPS assuming the BAMM forecast track.

Code: Select all

WHXX01 KWBC 061827
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1827 UTC MON SEP 6 2010
 
DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.
 
ATLANTIC OBJECTIVE AIDS FOR
 
DISTURBANCE GASTON (AL092010) 20100906 1800 UTC
 
        ...00 HRS...   ...12 HRS...   ...24 HRS. ..   ...36 HRS...
        100906  1800   100907  0600   100907  1800   100908  0600
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    17.5N  57.2W   17.4N  60.2W   17.5N  63.2W   17.5N  65.7W
BAMD    17.5N  57.2W   17.6N  60.2W   17.9N  62.9W   18.1N  65.3W
BAMM    17.5N  57.2W   17.3N  60.1W   17.2N  62.8W   17.2N  65.3W
LBAR    17.5N  57.2W   17.5N  60.2W   17.7N  63.5W   17.7N  66.5W
SHIP        30KTS          33KTS          41KTS          50KTS
DSHP        30KTS          33KTS          41KTS          50KTS
 
        ...48 HRS...   ...72 HRS...   ...96 HRS. ..   ..120 HRS...
        100908  1800   100909  1800   100910  1800   100911  1800
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    17.6N  67.9W   17.6N  71.5W   17.8N  74.9W   18.5N  79.4W
BAMD    18.5N  67.3W   19.0N  70.3W   19.6N  72.8W   20.2N  76.1W
BAMM    17.4N  67.6W   17.8N  71.2W   18.6N  74.5W   19.6N  78.4W
LBAR    17.9N  69.2W   17.9N  73.5W   18.2N  76.8W   19.1N  80.3W
SHIP        62KTS          80KTS          93KTS         111KTS
DSHP        62KTS          80KTS          70KTS          88KTS
 
         ...INITIAL CONDITIONS...
LATCUR =  17.5N LONCUR =  57.2W DIRCUR = 275DEG SPDCUR =  15KT
LATM12 =  17.1N LONM12 =  53.8W DIRM12 = 277DEG SPDM12 =  14KT
LATM24 =  17.0N LONM24 =  51.2W
WNDCUR =   30KT RMAXWD =   75NM WNDM12 =   30KT
CENPRS = 1011MB OUTPRS = 1013MB OUTRAD =  170NM SDEPTH =   S
RD34NE =    0NM RD34SE =    0NM RD34SW =    0NM RD34NW =   0NM
 
$$
NNNN




[ronjon]

12z GFDL: 110 kts and 964 mb pressure southwest of JAM in 5 days.

http://moe.met.fsu.edu/cgi-bin/gfdltc2.cgi?time=2010090612-gaston09l&field=Sea+Level+Pressure&hour=Animation

[jinftl]

Agree....a system at this latitude, heading west in early september in an active season, esp. if it makes it into the western carribean....there is no way to write this system off yet....maybe it won't get going until west of 80W...but if it is over the high tchp waters south of cuba at that time, we could see explosive development. Too soon to tell. Ex-Gaston not redeveloping in the next 48 hours doesn't mean he is d.o.a.

Even Katrina crossed the entire atlantic but didn't develop until in the bahamas...

From NHC report on Hurricane Katrina:

A tropical wave, which departed the west coast of Africa on 11 August, moved through the Leeward Islands and merged with the middle tropospheric remnants of Tropical Depression Ten on 19 August and produced a large area of showers and thunderstorms north of Puerto Rico. This activity continued to move slowly northwestward, passing north of Hispaniola and then consolidating just east of the Turks and Caicos during the afternoon of 22 August. Dvorak satellite classifications from the Tropical Analysis and Forecast Branch (TAFB) of the Tropical Prediction Center (TPC) began at 1800 UTC that day. The upper tropospheric trough weakened as it moved westward toward Florida, and the shear relaxed enough to allow the system to develop into a tropical depression by 1800 UTC 23 August over the southeastern Bahamas about 175 n mi southeast of Nassau.

I would caution not to put all your eggs in one basket concerning some models not redeveloping this. Remember these are the same models that never saw Gaston developing to begin with.

It is September in peak season with a nice LLC about to traverse the warm Caribbean waters. If I were a betting man, I would be in the redevelopment camp.

[ConvergenceZone]

Pretty much all models don't redevelop this one now so looking likely Gaston's first session as a TS is all we are going to see from it...

I don't think most of the models developed Hermine either did they? I could be wrong, but I think they all missed that one as well. The accuracy of the models this year isn't very impressive.

[lester]

Pretty much all models don't redevelop this one now so looking likely Gaston's first session as a TS is all we are going to see from it...

I don't think most of the models developed Hermine either did they? I could be wrong, but I think they all missed that one as well. The accuracy of the models this year isn't very impressive.

The NAM developed it into a hurricane but...it's the NAM

[ConvergenceZone]

WXMAN, are you still sticking to your "recurve out to sea" forecast?

[Macrocane]

I don't think most of the models developed Hermine either did they? I could be wrong, but I think they all missed that one as well. The accuracy of the models this year isn't very impressive.

The GFS was more or less consistent developing Hermine as well the Euro although they only began to develop it 3 or 4 days ago. The tropical models have been developing Gaston so that makes me think it should not be declared dead yet, remember 3 years ago the global models didn't see Felix until it was already a TS.