ATL GUSTAV: Tropical Depression - Discussion

[Nederlander]

I think we are all focusing a little too much on the models. Models can be wrong and the best thing to do is look at the cone and if you are in the cone start preparing. Don't panic but take the precautions and keep tuned to your local mets and the NHC. I think people depend on the models too much and don't realize that they will change off and on until the very end. If your area is in the cone then be prepared.

Glad you said this. I am on here reading around this morning and its like HOLY CRAP THE GFDL SHIFTED OR IMO THIS IS A _____ THREAT, OR THE NHC WILL MOVE THEIR CONE, etc...

The simple fact is that models shift with every update, this is a GOM threat (includes everyone on the gulf coast), and the NHC will do what they see fit with the forecast. The NHC isn't perfect, but they do a pretty good job of nailing down storms, at least in the near future. We have no idea what that ridge's intentions are.. it could move east, turning the storm. It could build west, sending Gustav toward mexico, or it could shift to the center, giving Gustav a choice to make... We dont know yet...

[jlauderdal]

Not a forecast, but central Lousiana to the Florida Big Bend should be getting ready.


Maybe all the Northern Gulf Coasters will luck out, and Gustav will never recover from Haiti. It does look pretty chewed up right now...

yep, we seem much closer to an idea today than yesterday, i like your thinking, pretty soon we can start taking some cards off the table, probably tomorrow and by process of elimination come up with a 250 mile solution for landfall by friday

[cycloneye]

The latest at 9:25 AM EDT:

[KWT]

Well maybe Ed but wouldn't exactly count on it, its going to have very favorable conditions and super heat content to work with. Its got a good 4 days now with only minimal land interaction ocne its away from Haiti and history tends to suggest that the region its headed into is classic RI territory.

Note the center is just west that burst of convection near the center, does look pretty poor right now and 50kts seems decent estimate and I wouldn't expect strengthening for a little longer yet but once its clear of Haiti I could see it strengthening very rapidly thanks to its tiny inner core.

[meteorologyman]

Can an eye grow bigger when storm strengthens or does it stay consistent?

[Frank2]

Last night Steve Lyon's mentioned that it's because the core is so small that it's more vulnerable to weakening...

Many are thinking of Katrina, but, thankfully each storm is unqiue in it's outcome...

TS Fay should be a good example of how things can turn out differently than originally forecast...

[KWT]

Yep Frank its tiny core hasn't helped Gustav at all but whilst its messier the inner core seems mainly intact and these little systems tend to go up as fast as they went down, I remember Dennis being a neat example of that.

[fasterdisaster]

I think we are all focusing a little too much on the models. Models can be wrong and the best thing to do is look at the cone and if you are in the cone start preparing. Don't panic but take the precautions and keep tuned to your local mets and the NHC. I think people depend on the models too much and don't realize that they will change off and on until the very end. If your area is in the cone then be prepared.

Uh...you do realize the cone is BASED on the models? There would be no cone if we did not have the constant twitches left and right of the models. The models are just as important as the NHC cone.

[fasterdisaster]

He lost convection but his overall convective structure remains the same after Haiti. There is a round burst of thunderstorms over the center and some very nice banding on the southern side as well as some good inflow. Outflow is decent but not great due to the ULL but as Sanibel pointed out that is fizzling and outflow will only be improving throughout today. Really I see no reason this shouldn't start some steady strengthening like we saw on Monday after about 12 hours.

[fasterdisaster]

Yep Frank its tiny core hasn't helped Gustav at all but whilst its messier the inner core seems mainly intact and these little systems tend to go up as fast as they went down, I remember Dennis being a neat example of that.

To be fair the tiny core was what made it a 90 mph hurricane instead of a 70 mph tropical storm.

[KWT]

It all depends on just how fast the inner core get back its previous shape, its still there though which probably has shaved 24hrs off the time needed!

[TexWx]

I was going to say "open wave" last night but didn't know for sure.
If it does come back, I do see a Fla/Bama storm...

[Myersgirl]

The latest at 9:25 AM EDT:

Where is the center of circulation?

[Derek Ortt]

there is also some northerly mid level shear over this.

Cuba may luck out as a hurricane for them is starting to look unlikely

[Derek Ortt]

the center is very poorly defined.

its not an open wave, but another bout of mountains will place Gustav in danger

[KWT]

what part of Cuba do you mean Derek, the eastern side or western side?

[DESTRUCTION5]

the center is very poorly defined.

its not an open wave, but another bout of mountains will place Gustav in danger

Man thats good news...Well for the short term anyway..

[gboudx]

I don't see where anyone posted jeff's latest update. Here ya go, so don't be caught off guard if Gus moves WSW today. jeff mentions this possibility.

Dangerous hurricane forecasted into the north-central Gulf of Mexico late this weekend.

Current:

Gustav has finally emerged off the SW coast of Haiti…and has turned toward the WNW per recon fixes. In fact the forward motion has slowed greatly and is less than 5mph as Gustav has yet to become caught in the faster steering of the ridge over FL. The high mountains of SW Haiti have disrupted the small inner core and the system has weakened to a 60mph TS with surface pressure of 996mb and winds of 40-45kts at the surface per the aircraft.

Track:

Per mid and upper level steering…showing a strong high pressure ridge over FL which Gustav should get caught within the southern part of this high within the next several hours and begin a westward motion. CMISS data shows this high centered over S FL ridging SW into the NW Caribbean. While the available model guidance does not suggest a WSW or SW motion…based on the position of this high such a motion is possible. The GFS continues to be trash…a far eastern outlier with a track along the N Cuban coast…which is highly unlikely. The GFS along with the NOGAPS make up the eastern side of the guidance envelop with the GFDL and HWRF nearly on top of each other down the middle and the EURO and CMC off to the western side of the clustering. It should be noted that the GFDL continues wide swings between model runs while both the CMC and GFS have been more stable…but are far outliers to either side.

For the short term a track toward the W or even WSW seems most likely as Gustav rounds the south side of the ridge over S FL. By late Friday into Saturday Gustav will begin to reach the SW side of this ridge and begin to turn toward the WNW and NW. At this time a new high pressure ridge will be building across the SE US and this high will be the controlling factor in determining Gustav’s final landfall location. Do not think the GFS weakness it is showing over the SE US will be a factor and this is why the GFS continues its strong right runs…and of a much weaker system.

Through 72 hours the forecast is fairly straight forward with a track toward the NW Caribbean Sea….thereafter the uncertainty increases to the point that the entire error cone would be at risk. At this point, extrapolation of the centerline NHC track is highly discouraged given the spread in the respected global guidance and the noted errors of TC forecasting at days 4 and 5. Equal and similar preparations should be made within the entire error cone from TX to the FL panhandle.

Intensity:

While Gustav has weakened due to land interactions…the system is now back over the warm waters with favorable upper level winds aloft. While the tiny inner core was disrupted, it should slowly rebuild itself as the cyclone tracks off toward the west. Conditions in the western Caribbean Sea are nearly perfect for rapid intensification, deep warm water within the start of the Gulf loop current, favorable light winds aloft, and a decent outflow channel on the SW side of the FL high to help expel and vent the system. The 06Z runs of the GFDL and HWRF are both at the extreme end of the intensity guidance showing a category 5 hurricane moving through the Gulf with very deep pressures of 892mb and 904mb, while SHIPS only shows 81kts at 96 and 120 hours. The NHC forecast maintains a major hurricane event into the central Gulf of Mexico with 120mph sustained winds nearly splitting the intensity guidance. Once the inner core of Gustav reforms there appears to be little to prevent intensification and Gustav could easily be stronger than NHC is forecasting in the Gulf and this is noted in their discussions.

Actions:

Residents along the US Gulf coast should be reviewing their hurricane plans and be prepared to activate those plans this weekend.

Residents should also keep vehicles at 50-75% fueled.

[gatorcane]

the center is very poorly defined.

its not an open wave, but another bout of mountains will place Gustav in danger

Man thats good news...Well for the short term anyway..

This is great news for folks upstream of Gustav. I have been questioning whether Gustav will ever become a major and this lends more support.

Bad news for Haiti.

[KWT]

Its both good and bad, should mean its a smaller system ,less surge but a smaller system will have a much better chance of hitting at nearer peak strength.

In the end a system like this only needs 24hrs over the heat content its going to go over to deepen 30-50mbs.