ATL Tropical Depression GUSTAV - Model Runs

[lamsalfl]

00Z NOGAPS crosses Hispaniola and heads North into Bahamas. Continues to feal a big weakness.

It better start moving to the NW, and I mean yesterday for the NOGAPS to verify. I can't throw out the possibility of this moving across Cuba and towards the Bahamas. Hispaniola? Just don't see it happening unless some radical reformation takes place...

Welcome to the second half of this decade!

[USTropics]

Is it just me or has the GFDL gone from developing Invest 94L into a Cat 5 in one run, to not developing even a tropical depression in the 00z?

[RL3AO]

Is it just me or has the GFDL gone from developing Invest 94L into a Cat 5 in one run, to not developing even a tropical depression in the 00z?

You are correct.

[USTropics]

Well until something develops at the surface and we have some reliable data input I think we have to completely throw all models out and go with what is currently happening in the surrounding atmosphere in terms of development and track. There is just no model consistency from run to run at all.

[Stratosphere747]

The wild swings in the GFDL intensity runs always make for some interesting conversation. Not many folks take them seriously this far out considering the present organization.

The upper cat 4 into Houston/Galveston with Dolly was another good one...

[RL3AO]

The wild swings in the GFDL intensity runs always make for some interesting conversation. Not many folks take them seriously this far out considering the present organization.

The upper cat 4 into Houston/Galveston with Dolly was another good one...

People take them serious when they show a major cane but throw it out when it shows nothing.

[Stratosphere747]

The wild swings in the GFDL intensity runs always make for some interesting conversation. Not many folks take them seriously this far out considering the present organization.

The upper cat 4 into Houston/Galveston with Dolly was another good one...

People take them serious when they show a major cane but throw it out when it shows nothing.

Maybe I should have clarified that those with a reasonable understanding of the tropics didn't take it seriously. More amusement than anything.

[USTropics]

I never expected a Cat 5 to verify (the GFDL is notorious for over doing systems). Like someone said, the only time I've seen RI is when the GFDL AND the HWRF are showing significant strengthening. None the less, you have to say going from a Cat 5 strength system to not even a tropical depression (especially when the 00z run is suppose to be one of the more better runs in terms of data input) is pretty telling. Just look at the other models, in order for the NOGAPS and the HWRF to verify this almost has to go NW or even NWN now. The GFS also shows no development but looking at AVN sat images you can clearly see deep convection developing to the northwest of the center (partially contributed to the peak of diurnal maximum as well). To clarify my remarks, all I'm saying is we really have to wait till the 2PM recon run for some ridge and atmospheric samplings so we can have better data input. The NHC has also upgraded this to red and believe a surface circulation is becoming better defined, so to show nothing developing is illogical.

[Clipper96]

(Ragging on the GFDL....)

The upper cat 4 into Houston/Galveston with Dolly was another good one...

You have to admit, though, that if Dolly had gone that way (through the Yucatan channel over the loop-current), should probably would have been a cat-4. Or worse. She had a very small, active core that was disrupted by the Yucatan; a mere 50 miles or so to the right would have enabled that to remain intact.

[Wx_Warrior]

New EURO says "no thank you" and sends it NE...Notice the ridge over Cen GOM, etc...Don't need recon to find a ridge.

http://www.ecmwf.int/products/forecasts/d/charts/medium/deterministic/msl_uv850_z500!Wind%20850%20and%20mslp!144!North%20America!pop!od!oper!public_plots!2008082500!!/

[Cyclenall]

There is something wrong with the GFDL model on 94L. I strongly doubt it is properly "working" since it doesn't even follow the thing on the fine grid. It's been doing this on and off thing for days. For a model to show a CAT5 and then 6 hours later nothing at all is not routine model flip-flopping.

[USTropics]

Actually that looks like 94L not developing and going into C America and 95L reforming to the south then going NE.

[SouthFloridawx]

Yeah... Euro showing not much of a ridge out there beyond 72 hours. Either is the GFS...

[SouthFloridawx]

[Clipper96]

Examining post-eclipse loops, the trough is clearly lifting northeast already and will not pick up 94.

http://www.nlmoc.navy.mil/cgi-bin/movie ... ic+hiresir

(Unofficial forecast)

I am leaning more toward a Jamaica hit now, but it should stay off Haiti and southeastern Cuba. I.e., major 'cane Gulf menace track rather than Yucatan/weaken/putter into TexMex as cat-1/2.

Development should be slow today as the trades are squeezed between Hispaniola and Venezuela, but increase dramatically on Tuesday in the Jamaica vacinity.

[Meso]

06z model runs trending less northerly and more to the West. I think this is why the models are differing so in intensity.. The GFDL at 18z last night, showed the storm tracking general NW then turning WNW in an area of little land resistance. This path seems to be the one where conditions are ripe and the storm has the best chances of developing. While on the 00z run there was far more land interaction and possibly harsher atmospheric conditions on the system, hence the system not really developing.. It goes without saying that land interaction will obviously be bad for development.. But I'm thinking if this follows the path of let's say the CLP5, in that location, it has a good chance of some strong development

[rockyman]

06z GFDL has system in the SE Gulf west of Key West, moving NW at 126 hours:

[Meso]

TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0651 UTC MON AUG 25 2008

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 INVEST (AL942008) 20080825 0600 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
080825 0600 080825 1800 080826 0600 080826 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 14.4N 68.2W 15.9N 70.4W 17.2N 72.2W 18.6N 73.6W
BAMD 14.4N 68.2W 15.9N 70.3W 16.9N 71.9W 17.4N 73.4W
BAMM 14.4N 68.2W 16.2N 70.4W 17.5N 72.0W 18.5N 73.4W
LBAR 14.4N 68.2W 15.9N 70.0W 17.3N 71.6W 18.3N 73.0W
SHIP 30KTS 39KTS 48KTS 54KTS
DSHP 30KTS 39KTS 48KTS 52KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
080827 0600 080828 0600 080829 0600 080830 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 19.3N 74.8W 20.3N 77.5W 20.8N 80.7W 21.6N 83.9W
BAMD 17.7N 74.9W 17.4N 78.1W 17.0N 81.2W 17.2N 84.8W
BAMM 18.9N 74.5W 18.7N 77.0W 18.3N 79.9W 18.6N 83.1W
LBAR 18.9N 74.2W 19.0N 77.1W 18.6N 80.9W 19.0N 85.1W
SHIP 59KTS 67KTS 72KTS 76KTS
DSHP 58KTS 66KTS 70KTS 74KTS

...INITIAL CONDITIONS...
LATCUR = 14.4N LONCUR = 68.2W DIRCUR = 310DEG SPDCUR = 12KT
LATM12 = 12.8N LONM12 = 66.4W DIRM12 = 297DEG SPDM12 = 15KT
LATM24 = 11.6N LONM24 = 63.4W
WNDCUR = 30KT RMAXWD = 60NM WNDM12 = 25KT
CENPRS = 1006MB OUTPRS = 1010MB OUTRAD = 180NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

[cycloneye]

WHXX04 KWBC 251128
CHGQLM
ATTENTION...NATIONAL HURRICANE CENTER

NCEP COUPLED GFDL HURRICANE MODEL FORECAST MADE FOR

TROPICAL DEPRESSION INVEST 94L

INITIAL TIME 6Z AUG 25

DISCLAIMER ... THIS INFORMATION IS PROVIDED AS GUIDANCE. IT
REQUIRES INTERPRETATION BY HURRICANE SPECIALISTS AND SHOULD
NOT BE CONSIDERED AS A FINAL PRODUCT. PLEASE SEE THE TPC/NHC
OFFICIAL FORECAST.


FORECAST STORM POSITION

HOUR LATITUDE LONGITUDE HEADING/SPEED(KT)

0 14.4 68.4 310./12.0
6 14.9 69.0 312./ 7.6
12 16.0 69.4 340./11.4
18 16.9 70.3 314./12.7
24 17.3 71.4 291./11.4
30 18.3 72.4 313./13.4
36 19.1 72.9 328./ 9.8
42 19.5 73.3 314./ 4.9
48 19.6 73.8 282./ 4.4
54 19.7 74.2 288./ 4.4
60 19.8 74.7 282./ 4.9
66 19.9 75.2 277./ 4.6
72 19.9 75.8 269./ 5.8
78 20.1 76.4 288./ 6.3
84 20.4 76.9 301./ 5.5
90 20.7 77.6 295./ 6.9
96 21.1 78.3 299./ 8.2
102 21.7 79.5 299./12.2
108 22.3 80.3 302./ 9.2
114 23.0 81.1 310./10.4
120 23.8 82.2 305./12.9
126 24.8 83.1 322./12.7

[SouthFloridawx]

I think development is imminent, but at the same time... I would tend to agree with you. 06Z again not showing much of a ridge to push her west.

06z model runs trending less northerly and more to the West. I think this is why the models are differing so in intensity.. The GFDL at 18z last night, showed the storm tracking general NW then turning WNW in an area of little land resistance. This path seems to be the one where conditions are ripe and the storm has the best chances of developing. While on the 00z run there was far more land interaction and possibly harsher atmospheric conditions on the system, hence the system not really developing.. It goes without saying that land interaction will obviously be bad for development.. But I'm thinking if this follows the path of let's say the CLP5, in that location, it has a good chance of some strong development