ATL: GASTON - Models

[cycloneye]

This year, it has been a failure for the ECMWF (Sorry EURO followers ) CMC and GFS are the kings in 2010.

[caneseddy]

This year, it has been a failure for the ECMWF (Sorry EURO followers ) CMC and GFS are the kings in 2010.

Shhhh....don't let Rock hear you

It's freaky that the CMC and GFS (the best models so far) have the same solution with Gaston in the southern Bahamas

[Vortex]

Looking more like this may pass just north of th islands...Good for them but this may allow gaston to become a powerhouse in the bahamas if it miss the greater antilles...

[ColinDelia]

18z SHIPS

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 30 31 34 37 40 48 58 68 77 85 93 100 107
V (KT) LAND 30 31 34 37 40 48 58 68 77 85 93 100 107
V (KT) LGE mod 30 31 32 35 37 44 53 64 79 94 107 116 121

[Vortex]

pretty remarkable intensity forecast there from lgem...been on this for several runs now..looks like after 72hours it really ramps up...

[ColinDelia]

Yeah, Vortex and given its superior record the past 3 years - one could even say dominant last year - it has to be taken seriously.

[BigA]

I do not know whether the NAM is any better at upper level features than it is with tropical cyclones (which is to say poor), but the 18z run forecasts a perfect upper level high over Gaston by the 84 hour time frame. This may be what SHIPS and LGEM are seeing.

[Comanche]

What interests me the most as far as that intensity forecast just posted is that it doesn't deal with the dry air that surrounds it, but more importantly, doesn't deal with this-

[youtube]http://www.youtube.com/watch?v=wgTPH5y1-ZI[/youtube]

[ColinDelia]

BigA,

SHIPS takes Gaston from 30 knots to 107 knots. That's +77 knots

The major contributors are:
SST Potential: 37 knots
Vertical Shear Direction: 19 knots
Sample Mean: 13 knots (This is factor for all storms get for the average change)
Ocean Heat Content: 7 knots

Those 4 factors are 76 knots.

Then there are a number of lesser factors which pretty much cancel each other out.
5 positive factors with values 4,3,1,1,1
2 negative factors with values 6,3

[SFLcane]

18z GFS thus far isn't doing much of anything with ex-gaston...

[BigA]

[quote="Comanche"]What interests me the most as far as that intensity forecast just posted is that it doesn't deal with the dry air that surrounds it, but more importantly, doesn't deal with this-

quote]

I would imagine that it does, in the sense that the TUTT is factored into the shear forecast the the model uses. I could be wrong, though.

[ColinDelia]

18z GFS handles the ULL in pretty much the same way as 12z. The upper level high to the North moves west with Gaston and the ULL
regresses quickly westward

At 24 hours the ULL is over the Dominican Republic

At 48 hours the Upperl Level High is dominant all the way to the Dominican Republic. The ULL is west of there.

At 72 hours the ULL is over central Cuba and Gaston is in the NE Caribbean. A little more than 800 miles distant.
It's the ideal ventilating position but a little too far away I think.

At 90 hours the ULL is over the tip of western Cuba and still moving west after that

(edited to denote UPPER level high)

[SFLcane]

18z barely developes this thing...If have of the nonsence the GFS predicts panned out i probably would not have a house right now.

[cycloneye]

18z barely developes this thing...If have of the nonsence the GFS predicts panned out i probably would not have a house right now.

The 06z run did the same not developing it.

[SootyTern]

LOL at Steve Martin.

Aren't ULL's notorious for not behaving as forecast?

[perk]

Completely gone at hour 144.

[BigA]

18z GFS handles the ULL in pretty much the same way as 12z. The high to the North moves west with Gaston and the ULL
regresses quickly westward

At 24 hours the ULL is over the Dominican Republic

At 48 hours the High pressure is dominant all the way to the Dominican Republic. The ULL is west of there.

At 72 hours the ULL is over central Cuba and Gaston is in the NE Caribbean. A little more than 800 miles distant.
It's the ideal ventilating position but a little too far away I think.

At 90 hours the ULL is over the tip of western Cuba and still moving west after that

Yeah, if Gaston tracks north of the islands, it looks like it will be in a position to possible become a "Bahama Bomber" storm. But a number of things have to come together for this scenario to pan out.

[ConvergenceZone]

outside of the chance of the BOC wave developing and Gaston potentially developing, the tropics have pretty much gone quiet....

[ColinDelia]

The 12z Canadian and the 18z GFS look pretty similar.

[ROCK]

This year, it has been a failure for the ECMWF (Sorry EURO followers ) CMC and GFS are the kings in 2010.

thats not true Luis....look at this run...the same as EURO...west carib....