ATL GUSTAV: Tropical Depression - Discussion

[mattpetre]

Gustav is not behaving like most models predicted at this point. That much is obvious. He waited too long at the tip of Haiti and now he is shooting much further SW than they predicted. Tomorrow may result in much of the same long term, but I suspect that we will see a significant trend west and maybe even a few non-CONUS hits.

[txag2005]

I dont know..I see the high clearly oriented more to the east on this run..especially 108 hours compared to the 114 hours 18z

By that time it is different. However...if you look at the 60-72 hr point...which is really where the end game is going to be made...it is stronger and further west.

As I have stated over and over: When I look at the globals...especially the GFS...and try to forecast a storm...I am not really looking at what it is doing with that vortex...especially since it doesn't have the resolution to find it or keep it at the intensity it should be. I am looking at steering flow. Since the key factor in the final landfall of Gustav will be determined over the course of the next 48-72...I want to know the strength of the ridging...not only off the SE US coast...but over the plains. If the plains high is stronger and further west during this period...it will impart a more westerly motion to Gustav during that period. So on Sat evening...instead of being at 22.5/84.5...its at 22/86...that makes a difference in the landfall.

Again...my area of concentration on this storm is not at 108 hrs. I think it is pretty much set in stone which direction it will be moving at that point...NNW. The question will be how far west did it get BEFORE it starts that movement...and that will be determined by that period b/w60-72 and even 90 hours from now.

I know you or anyone else can't call where this thing will land, but does the analysis above mean Houston is at risk for this storm? Yesterday I believe the NHC Discussion mentioned Texas was not a big possibility at the time, and based on some of the east model shifts I figured we were out of the weeds.

Just curious how the above analysis fares for a potential Houston/SE Texas landfall.

[Air Force Met]

I think you and I actually see the second ridge as being just as important or more than the first, but don't you also believe this initial starting point (as in what it does for the next 24hr) as being just as important for final landfall too?

Of course I do. I didn't say it wasn't important. However, if the central plains ridge isn't there (take it off the charts)...this storm goes into the west coast of FL or the eastern panhandle....regardless of what it does in the next 24 hrs.

You have to add it all up...and right now...I give more weight to the plains high as it moves eastward and links up with the high off the SE US coast. The SE US high doesn't change that much. Its the plains high that is the one in transition and that is always the forecast challenge (transitioning highs and trofs).

[mattpetre]

I will tell you right now that Houston and even Corpus Christi are not out of the weeds at this point. There is much to be learned about Gustav at this point.

[HouTXmetro]

I know you or anyone else can't call where this thing will land, but does the analysis above mean Houston is at risk for this storm? Yesterday I believe the NHC Discussion mentioned Texas was not a big possibility at the time, and based on some of the east model shifts I figured we were out of the weeds.

Just curious how the above analysis fares for a potential Houston/SE Texas landfall.

By morning GUS will be moving NW and we will all be discussing a FLA Panhandle strike...lol

[mvtrucking]

It is right on the forecast points IMO. (Will skirt just north of Jamaica at WNW)

[mattpetre]

I think you and I actually see the second ridge as being just as important or more than the first, but don't you also believe this initial starting point (as in what it does for the next 24hr) as being just as important for final landfall too?

Of course I do. I didn't say it wasn't important. However, if the central plains ridge isn't there (take it off the charts)...this storm goes into the west coast of FL or the eastern panhandle....regardless of what it does in the next 24 hrs.

You have to add it all up...and right now...I give more weight to the plains high as it moves eastward and links up with the high off the SE US coast. The SE US high doesn't change that much. Its the plains high that is the one in transition and that is always the forecast challenge (transitioning highs and trofs).

I appreciate your candor and defer to your expertise. I just have said for some time now that it wasn't the current ridge that really makes the final decision as far as where this goes in the GOM. I think that was evident in the models from early on, but it seems that many want to forget that the current steering influences are just that current and not 5 or 6 days out.

What do you think? Landfall on Tues, Wed, or Thur? I know that depends on position and stalling, just curious as to a guess.

[NC George]

http://www.metservice.gov.jm/radarpage1.asp

...and I thought the Cuban radar was bad. No updates until 8 am???

[mattpetre]

It is right on the forecast points IMO. (Will skirt just north of Jamaica)

But the forecast points 3 hrs ago were not skirting Jamaica.

[mattpetre]

http://www.metservice.gov.jm/radarpage1.asp

...and I thought the Cuban radar was bad. No updates until 8 am???

Yeah, I can't tell if it's current or not, but it sure doesn't look to be as long range as the Cuban ones... guess the Russians being there was good for something.

[Air Force Met]

It is right on the forecast points IMO. (Will skirt just north of Jamaica)

Its south of the forecast points...at least by 30 miles. The forecast was flawed from the beginning. They had it moving due west...even though they said it was moving wsw. Looks to be moving almost SW.

[Air Force Met]

What do you think? Landfall on Tues, Wed, or Thur? I know that depends on position and stalling, just curious as to a guess.

Probably Tuesday. Don't see it hanging around.

OK. Off to bed. 0500 comes early.

[mattpetre]

TWC is giving the same ol' forecast now, I guess it's too late for them too. If Gustav goes S. of Jamaica, I'm taking that one as a forecast "win" for me. Gotta play disc golf tournament this weekend, so better get some sleep.

[Matt-hurricanewatcher]

I think it is strengthing, here is my guest on what the recon will find.

Flight level winds 51 knots
SMRF 45 knots
Pressure 996 millibars

[Jagno]

Matt;
Please explain why your Lake Charels, LA prediction with Gus.

[Normandy]

Evening folks, thought I'd share my thoughts.
Radar from Cuba indicates that Gustav has lost a severe amount of lattitude today, and right now is actually a good deal south of the Southwestern peninsula of Haiti. Motion seems to be WSW or even SW at times, and it is evident that the center of this cyclone will AT LEAST go over Jamaica, and possibly skirt the southern coast. This has large implications on the track in my opinion, and will likelt put the Yucatan at risk for landfall. This move southward will put the center off forecast track by some 40 miles at least, and will cause the NHC to shift their cone further west. Click below for evidence of this Southwest move.

http://www.insmet.cu/asp/genesis.asp?TB ... AXw01a.gif

This also changes intensity as well. Now that it is CRYSTAL clear that the cyclone will have little, if ANY, interaction with Cuba over the next few days. It will have more water to work with and that will likely lead to greater intensification. I do believe this storm will become a major sometime before entering the Gulf of Mexico. Here are a couple of important things to consider when trying to pin down a landall zone:

1) Where does it leave the Caribbean Sea, or as AFM says, how far west will it go? We know that this will be moving northward in some form or fashion by sunday/monday, but how far west will it get before this turn. Here are some benchmarks we can set and what they might suggest:

Impact on the Yucatan = LA/TX Border westward threat.
Through the Channel = LA/MS threat
Over ANY part of Cuba = MS/Eastward threat

This is just my opinion, and assuming the cyclone does not make a hard right turn after turning NW, which is entirely possible. I just don't see a trough strong enough to induce any NNE motion at this time. This storm is YET again proving just how hard TC forecasting is, and I have much respect to those who make forecasts for these professionally.

[Matt-hurricanewatcher]

Matt;
Please explain why your Lake Charels, LA prediction with Gus.

Strong high allowing for a more westward track. Rita, Humberto, Lili like track, this is because some of the models form a high to the north like the one like Fay to push it more westward. If this high turns out to be weaker then New orleans could still be at risk.

[mattpetre]

Matt;
Please explain why your Lake Charels, LA prediction with Gus.

Don't worry, it's simply because I live in Houston, so a TX landfall would be "-removed-" to many and also I have thought all along that NO was too far East for this particular pattern. If I had to go with what I really believed right now it would be just N. of Corpus Christi on the TX coast. I just believe the latter high in the plains is going to strengthen the SE high and push Gustav further west than most believe. All very amateurish forecasting and should not be believed in the slightest. Stick with the NHC and hope they are wrong about NO at this point.

[Jagno]

Matt;
Please explain why your Lake Charels, LA prediction with Gus.

Don't worry, it's simply because I live in Houston, so a TX landfall would be "-removed-" to many and also I have thought all along that NO was too far East for this particular pattern. If I had to go with what I really believed right now it would be just N. of Corpus Christi on the TX coast. I just believe the latter high in the plains is going to strengthen the SE high and push Gustav further west than most believe. All very amateurish forecasting and should not be believed in the slightest. Stick with the NHC and hope they are wrong about NO at this point.

hmmmmmm, I'm near the TX/LA boader, near the coast........Calcasieu/Cameron parish line so I was actually liking their track. LOL

[mattpetre]

Matt;
Please explain why your Lake Charels, LA prediction with Gus.

Don't worry, it's simply because I live in Houston, so a TX landfall would be "-removed-" to many and also I have thought all along that NO was too far East for this particular pattern. If I had to go with what I really believed right now it would be just N. of Corpus Christi on the TX coast. I just believe the latter high in the plains is going to strengthen the SE high and push Gustav further west than most believe. All very amateurish forecasting and should not be believed in the slightest. Stick with the NHC and hope they are wrong about NO at this point.

hmmmmmm, I'm near the TX/LA boader, near the coast........Calcasieu/Cameron parish line so I was actually liking their track. LOL

I just meant hope they are wrong by some margin of error so NO is still in existence after this Labor Day weekend.