ATL GUSTAV: Tropical Depression - Discussion

[cycloneye]

The latest:

[Air Force Met]

IMO based on satellite recon will find a strengthening 80-85mph cane and a pressure between 978-984.

I don't know if the winds will be caught up (they may)...but I agree with your pressure. I expect lower 970's by the time they leave.

[Ptarmigan]

Looking at Gustav, it looks like it is already a hurricane. It expanded quite nicely while over Jamaica. Since it move slowly at 6 mph, a good portion of Jamaica got 12 to 16 inches of rain. I would not be surprised if it becomes a major hurricane by tonight.

[RL3AO]

983mb extrapolated from recon.

[txwatcher91]

IMO based on satellite recon will find a strengthening 80-85mph cane and a pressure between 978-984.

I don't know if the winds will be caught up (they may)...but I agree with your pressure. I expect lower 970's by the time they leave.

The winds are based on a clearing eye, typically a eye that looks like this will have at least 85mph winds, but it may not. Hard to say, but lower 970s wouldn't surprise me at all.

Do you expect this trough to lift out soon because if not it could shear Gustav to a TS in the gulf.

[gboudx]

well after reading jeff's emil, i think texas is gettin ready!! think i am going to go to the store today... before the rush,... and if i get gas now, it will be gone before next week!! i have a 4 runner and a camaro.... gas guzzlers!!!

Can you post it? I used to get them, but I don't have that email address anymore.

gale, either jason or myself are posting jeff's emails at: viewtopic.php?f=29&t=102827

[Yankeegirl]

Here Kelly, I left out his contact numbers.... didnt think he wanted them posted all over the net....
Large dangerous hurricane forecasted into the northern Gulf of Mexico early next week.

Current:

Gustav has been moving across Jamaica overnight and is now moving off to the west of the island. Recon. aircraft is currently investigating the system and has found that the storm has significant grown in size overnight. Gustav continues to move toward the west at around 10mph and a gradual increase in forward speed and turn toward the WNW is expected today. The satellite appearance shows well defined upper level outflow and the recon. reported good banding features…it will not take long over the deep warm NW Caribbean waters for Gustav to intensify.

Track:

It all comes down to timing…

The weak high over FL is producing a slow westward motion at this time…this high will weaken and the SW ATL sub-tropical ridge will build into the eastern Gulf of Mexico allowing a WNW to NW motion toward the SE Gulf. There is a break or weakness on the NW side of this developing ridge over the SE US extending back into the Gulf of Mexico for several hundred miles associated with an upper level trough. Based on water vapor images this morning it is very clear this trough is still digging southward toward the northern Yucatan likely being helped by an upper level vortex W of Tampa. This trough may impart a more NNW motion over the NW Caribbean Sea if it hangs on longer than forecast…but should begin to lift out to the NE late Saturday…allowing Gustav to return to a NW motion on the west side of the sub-tropical high.

The forecast would be fairly straight forward…but now the models build in a ridge over the OH valley early next week behind the departing SE US trough and block Gustav’s northward track…sound familiar…same thing that happened with Fay. This imparts a westward track at or just before landfall and a much greater threat to the upper TX and SW LA coasts.

NHC has adjusted their forecast track westward from 400pm yesterday and slowed the forward motion to split the guidance cluster down the middle. It should be noted that some of the most reliable track guidance still shows a landfall well east of the NHC track toward SE LA and SW MS. The tight clustering seen yesterday afternoon toward SC LA is all but gone this morning and we really do not have any better answers than yesterday.

It is important to note that a larger part of the TX coast has been placed in the forecast error cone…this cone is not created by the model spread, but the determined error in past tracks at days 4-5 which are between 150 and 300 miles.

Intensity:

Once Gustav pulls away from Jamaica there is little to impede rapid development. Looking at the water vapor images shows a well defined upper level outflow pattern established over the TC with a 200mb anticyclone producing good venting aloft. SST’s over the NW Caribbean are very warm a deep with some of the highest oceanic heat content in the entire ATL basin. All intensity guidance brings the storm to a major hurricane and a category 4 in the NW Caribbean looks like a safe bet. Once in the Gulf Gustav will track nearly along the loop current and this should maintain its intensity until it reaches the northern Gulf where the heat content decreases and a little SW shear may impact the storm. We have seen numerous powerful hurricane weaken as they approach the US Gulf coast…but their effects are still very devastating.

It should be noted that the new NHC guidance package shows a very large hurricane in the Gulf with 34kt (TS force) wind diameter of 250 miles and 50kts winds of 150 miles at forecast point 26.4/88.1 with sustained core winds of 110kts (125mph).

Actions:

Pre disaster declaration was approved by President Bush on Thursday for 61 TX counties.

State of TX is planning for the strike of a category 4 hurricane on the TX coast and has fully activated the state Hurricane Response Plan.

Fuel plan was activated Thursday morning and there has been significant demand increase in the SE/upper TX coast area. Suppliers have all fuel terminals at full distubituion capacity and a flooding the entire retail system with as much fuel as possible. There have been a few supply issues in Harris County…but these have been corrected. Today and Saturday the fuel plan will continue to surge to local retail along the coast and begin to push supplies to the evacuation routes and contra-flow corridors.

DPS and TXDOT will begin preparation for mass evacuations of SE TX north of Port Lavaca. TXDOT will begin preparing evacuation routes…removing debris and cleaning the US 290 hurrevac traffic lane (outbound shoulder). Contra-flow exchange points on I-10, US 290, I-45, US 37, and US 59 NE will be prepared today and early Saturday. All construction on evacuation routes will be suspended today.

State shelter hubs in Waco, Tyler, El Paso, Dallas, and San Antonio have been fully activated.

Alamo Regional Command was been fully activated to coordinate special needs and possible public evacuations.

Air evacuation of special needs (critical care facilities, hospitals, nursing homes) in the Beaumont/Port Arthur area may begin on Saturday…to locations in El Paso and Dallas.

H-120 timeline will likely be adjusted this morning due to forecast track changes overnight and slowing of the potential impact.

Preparations:

Residents should fuel vehicles and maintain 75-100% fuel through the weekend.

Make sure all hurricane supplies are on hand.

Residents in the coastal surge/evacuation zones should review their plans and be fully prepared to leave if ordered to do so.

Due to the upcoming holiday weekend many people will be away from their computers.

I am making myself available via phone if there anyone needs an update on the storm. I will continue with the e-mail updates and encourage all the continue to check into whichever source for your weather information.

[dwg71]

983mb extrapolated from recon.

Winds are no where near there though... 47KT flight level is highest and they are flying through some pretty thick convection, i doubt its that low. maybe..

[Just Joshing You]

Well, every reading is consistently getting lower, and there's many 983 readings to pick from. 983.4,.2,.6 et al.

[Just Joshing You]

60 kt FL, 64 kt SFMR. 983 MB.

[CrazyC83]

60 kt FL, 64 kt SFMR. 983 MB.

Such data supports a 60 kt intensity right now as a blend of the FL (54 at surface) and SFMR (64) estimates.

[RL3AO]

Lets wait until they get to the NE quad. That will probably support 60 to 65 kt.

[gboudx]

Friday noon update from jeff has been posted here. Texas residents need to read this.

viewtopic.php?f=29&t=102827&p=1796072#p1796072

[RL3AO]

URNT12 KNHC 291739
VORTEX DATA MESSAGE AL072008
A. 29/17:20:50Z
B. 18 deg 44 min N
079 deg 08 min W
C. 700 mb 2961 m
D. 57 kt
E. 300 deg 25 nm
F. 027 deg 048 kt
G. 300 deg 036 nm
H. 984 mb
I. 10 C/ 3048 m
J. 13 C/ 3044 m
K. 9 C/ NA
L. OPEN NE
M. C15
N. 12345/7
O. 0.02 / 1 nm
P. AF307 1007A GUSTAV OB 06
MAX FL WIND 48 KT NW QUAD 17:10:40 Z
SURFACE WIND OBSERVED VISUALLY


Lets see if that eyewall closes in the next pass. Right now its open.

[Just Joshing You]

62 FL winds in 1002 pressure?

[cpdaman]

considering she moved her center off land 6 hours ago, she appears to be doing quite fine

still awaiting sample of NE quad

[shawn67]

http://hadar.cira.colostate.edu/ramsdis/online/trop_ge_storm_relative_0.html

From watching this it looks to me like it is dead on for the NHC 00z forecast point (it might get there alittle early) but it looks like Gustav will cross about 20 miles south of "little" Cayman Island

[Ed Mahmoud]

Bastardi says a sub 920 Cat 5 in the Gulf, weakening to Cat 3 by landfall, and he has no serious arguments with NHC path. He was showing the 5 am path, but the Eastward shift on the 10 am path wasn't huge.

[Air Force Met]

IMO based on satellite recon will find a strengthening 80-85mph cane and a pressure between 978-984.

I don't know if the winds will be caught up (they may)...but I agree with your pressure. I expect lower 970's by the time they leave.

The winds are based on a clearing eye, typically a eye that looks like this will have at least 85mph winds, but it may not. Hard to say, but lower 970s wouldn't surprise me at all.

Do you expect this trough to lift out soon because if not it could shear Gustav to a TS in the gulf.

I have no idea what this trof is going to do. I've spent the better part of the morning trying to figure it out...its that big of a player in my mind.

[gboudx]

BTW, the LSU/App st game was moved to 10am due to Gustav. No word yet on if it will still be televised.

I have no idea what this trof is going to do. I've spent the better part of the morning trying to figure it out...its that big of a player in my mind.

AFM, I posted a question in the Questions thread in the TA regarding this trough. If you get a chance and have time, can you take a look at it. No sweat if you can't.