ATL GUSTAV: Tropical Depression - Discussion

[Sabanic]

Will someone pls post a water vapor link? Can't seem to locate mine.

Thanks

My 6:05am post...

Thanks Ed

[perk]

as i stated prior to bed

i feel bad for the folks on the gulf coast, the panic level has risen high and they were 4 days away w/ lots of uncertainty, this morning i see a UGLY GOM area with a trough getting sharper (doesn't look favorable for the next 36 hours) but then again gustav is gustav the turtle (or he has been) should strengthen steadily today as he is coming off of jamaica, where he heads i have ZERO confidence in, FL keys don't go to bed on this one either.

I just checked the WV loop and that trough does look strong. Florida CAN'T rest easy right now the NHC mentions the possibilty of shifting things way east.

I just read that discussion, and i saw nothing where the NHC indicates an east shift.

[Sabanic]

They mention it perk, as do most of the NWS discussions. Just a possibility, but one that is there. Just look at some of the model runs this AM. They are still picking up on it. Who knows???

[KWT]

Whilst LA still looking more and more likely everywhere still need to watch this.

Anyway pressure down to 988mbs, looks like its now deepening as it moves offshore into the super high heat content of the NW Caribbean, expect RI to kick in sooner rather then later given the current structure still looks great.

[TampaFl]

NATIONAL WEATHER SERVICE MOBILE AL
430 AM CDT FRI AUG 29 2008

MANY OF US ALONG THE ALABAMA...
NORTHWEST FLORIDA GULF COAST MAY HAVE BEGUN TO ENTERTAIN THE IDEA
THAT GUSTAV WOULD MORE LIKELY MAKE LANDFALL FARTHER WEST OF OUR
AREA...BUT BEING THIS EARLY IN THE GAME THAT IS PRE-MATURE. THERE
ARE COMPLICATING FACTORS IN THE FORECAST MAKING THE TRACK FORECAST
OF GUSTAV PROBLEMATIC. THE MAIN FACTOR THAT COULD HAVE A
SIGNIFICANT INFLUENCE ON THE TRACK OF GUSTAV EARLY ON IS THE UPPER
TROUGH EXTENDING SOUTHWARD OVER THE GULF FROM THE UPPER LOW OVER
NORTHEAST GEORGIA. THAT TROUGH EXTENDS DEEPER INTO THE GULF THAN
WHAT MAY HAVE BEEN PREVIOUSLY THOUGHT...AND APPEARS TO STILL BE
DIGGING AS IT IS SHARPENED UP TO THE SOUTH BY THE SMALL UPPER VORTEX
SEEN SOUTH OF APALACHICOLA. THAT TROUGH MAY START TO INFLUENCE THE
MOTION OF GUSTAV EARLY ON IN THE GAME...AND COULD REQUIRE A BIT OF A
SHIFT OF THE OFFICIAL TRACK BACK TO THE EAST ON SUBESQUENT FORECAST
PACKAGES (THAT IS NOT CERTAIN...BUT A POSSIBILITY). WE CAUTION OUR
COMMUNITIES TO NOT FOCUS ON THE LITTLE BLACK DOTTED LINE ON THE
INTERNET IMAGES...AND INSTEAD WE SHOULD STRESS THAT THERE ARE LIKELY
TRACK ERRORS INVOLVED HERE. THE AREA OF UNCERTAINTY (THE "CONE")
STILL ENCOMPASSES MUCH OF OUR AREA FOR VERY GOOD REASONS...AND WE
ARE NOT OUT OF THE WOODS YET.

Here you can see what NWS Mobile is talking about. Notice how far down in the GOM it goes - & it does not appear to be moving much-just digging more south. Could this pull Gustav more to the East Central/East GOM? Comments from Pro Mets apperciated.

http://metofis.rsmas.miami.edu/~dortt/satellite/Miami/WV/atl_wv1_loop.gif

[cpdaman]

KWT where do you have the center as of 7 am?

[TampaFl]

Will someone pls post a water vapor link? Can't seem to locate mine.

Thanks

here you go.


http://metofis.rsmas.miami.edu/~dortt/satellite/Miami/WV/atl_wv1_loop.gif

[perk]

They mention it perk, as do most of the NWS discussions. Just a possibility, but one that is there. Just look at some of the model runs this AM. They are still picking up on it. Who knows???

Show me where the NHC discussion mentions it cause that's what the post i responded to said.

[KWT]

I can see that torugh digging down quite far, will be interesting to see how Gustav responds to it, recon montion is WNW right now.

A eastward jog from the track brings N.O back into play as well as possibly east to Mobile...

[Air Force Met]

Here you can see what NWS Mobile is talking about. Notice how far down in the GOM it goes - & it does not appear to be moving much-just digging more south. Could this pull Gustav more to the East Central/East GOM? Comments from Pro Mets apperciated.

http://metofis.rsmas.miami.edu/~dortt/satellite/Miami/WV/atl_wv1_loop.gif

Yes.This may be what the GFDL has been seeing. This trof will have a significant impact if it hangs around. The forecasting of these trofs are difficult and could prove to be a fly in the ointment if it hangs around. As Gustav strengthens...it will be steered more by the layer in which this trof resides...and if it doesn't move (which they are notorious for doing...or not doing....however you look at it)...it will cause all the tracks to shift right for at least a couple of days. The bend to the left looks like it still will happen...but with the trof...Gustav could start its NW movement a lot sooner and it could even be more NNW.

[hiflyer]

http://www.insmet.cu/asp/genesis.asp?TB ... p200Km.gif

Full mosaic of Cuba radars......and thanks to whoever kept the Gran Piedra running so well as that site was definitely outperforming other cuban sites...nice job.

[KWT]

KWT where do you have the center as of 7 am?

Recon shows the center to be around 18.11N and 78.10, motion appears to be close to WNW, a bit more northerly motion then was expected.

AFM, does that mean a bigger threat to N.O if it does take a WNW bend from a further easterly position?

[Air Force Met]

They mention it perk, as do most of the NWS discussions. Just a possibility, but one that is there. Just look at some of the model runs this AM. They are still picking up on it. Who knows???

Show me where the NHC discussion mentions it cause that's what the post i responded to said.

Its implied from:

SOME OF THE
MODELS...SUCH AS THE GFS/GFDL/HWRF...ARE SHOWING THIS LOW CREATING
ENOUGH OF A WEAKNESS IN THE BERMUDA HIGH TO ALLOW A MOTION MORE
TOWARD THE NORTH-NORTHWEST AS THE SYSTEM CROSSES CUBA. IT WOULD NOT
BE SURPRISING IF THAT TRACK BRIEFLY OCCURRED...BUT IN THE
LONGER-TERM...A HIGH OVER THE OHIO VALLEY IS EXPECTED TO CAUSE
GUSTAV TO GRADUALLY BEND TO THE LEFT.

If it is moving more NNW...that is a more eatward component. Even with a bend back to the left (which at the 4am they have it moving at 295 degrees) it would still makes landfall further east. A NNW track would shift the track to the east for most of the points.

[Sabanic]

Here ya go PERK . . .


TROPICAL STORM GUSTAV DISCUSSION NUMBER 18
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072008
500 AM EDT FRI AUG 29 2008



THE MID-LEVEL RIDGE OVER FLORIDA THAT HAS BEEN
STEERING THE STORM WESTWARD IS FORECAST TO WEAKEN TODAY. THE
BERMUDA HIGH IS THEN EXPECTED TO BUILD IN FROM THE WESTERN ATLANTIC
AND CAUSE GUSTAV TO MOVE MORE TOWARD THE NORTHWEST OVER THE
WEEKEND. ONE BIG QUESTION IS THE EVOLUTION OF A MID- TO UPPER-
LEVEL LOW OVER THE SOUTHEASTERN UNITED STATES. SOME OF THE
MODELS...SUCH AS THE GFS/GFDL/HWRF...ARE SHOWING THIS LOW CREATING
ENOUGH OF A WEAKNESS IN THE BERMUDA HIGH TO ALLOW A MOTION MORE
TOWARD THE NORTH-NORTHWEST AS THE SYSTEM CROSSES CUBA. IT WOULD NOT
BE SURPRISING IF THAT TRACK BRIEFLY OCCURRED...BUT IN THE
LONGER-TERM...A HIGH OVER THE OHIO VALLEY IS EXPECTED TO CAUSE
GUSTAV TO GRADUALLY BEND TO THE LEFT. HOWEVER...THERE IS A LARGE
UNCERTAINTY IN THE TIMING AND SHARPNESS OF THE BEND. THE UKMET AND
GFS HAVE HAD LARGE CHANGES TO THEIR FORECAST FROM THE PREVIOUS
RUNS.

[Air Force Met]

KWT where do you have the center as of 7 am?

Recon shows the center to be around 18.11N and 78.10, motion appears to be close to WNW, a bit more northerly motion then was expected.

AFM, does that mean a bigger threat to N.O if it does take a WNW bend from a further easterly position?

Yeah...that would be bad news. You don't want a powerful storm moving WNW or even NW up the Mississippi delta.

[Sihara]

Yes.This may be what the GFDL has been seeing. This trof will have a significant impact if it hangs around. The forecasting of these trofs are difficult and could prove to be a fly in the ointment if it hangs around. As Gustav strengthens...it will be steered more by the layer in which this trof resides...and if it doesn't move (which they are notorious for doing...or not doing....however you look at it)...it will cause all the tracks to shift right for at least a couple of days. The bend to the left looks like it still will happen...but with the trof...Gustav could start its NW movement a lot sooner and it could even be more NNW.

This answers a question I had this morning, listening to our Hazardous Weather Outlook for the Labor Day Weekend. There was a reference to Gustav possibly affecting our weather in terms of rain, th-storms. And it said residents & visitors planning on beach trips should monitor the forecasts concerning Gustav. First time I heard this on the hazardous, so got to thinking there must've been a slight rightward adjustment to the forecast track for some reason.

[HURAKAN]

[KWT]

Sabanic, yep it does need to be watched, some models have been lifting out this system sooner, even the ECM which ends further west brings it across the western edge of Cuba.

Current motion seems to be close to 300 if based on recon, very interesting, torugh needs to lift out soon if this isn't going to pick up some major latitude soon.

[rockyman]

If the system moves north quicker, it seems that it would reach the coast 6-12 hours quicker than if it moves more to the west. The GFDL is showing hurricane force winds on the coast as early at 7am Monday (between 72-78 hours from 6z)...

The 06z GFDL shows landfall between 78 and 84 hours...either in far SE LA or close to Bay St Louis, MS

[gomwatch]

Moved to questions forum.