ATL GUSTAV: Tropical Depression - Discussion

[lamsalfl]

Another note about the Weather Underground hurricane hunter flight path, the wind barbs you see and the colors that represent categories of hurricane, are flight level winds, not surface winds.

It says Surface on the map?

What is SFMR.

[RL3AO]

URNT12 KNHC 260826
VORTEX DATA MESSAGE AL072008
A. 26/07:36:30Z
B. 17 deg 06 min N
071 deg 47 min W
C. 700 mb 2986 m
D. 76 kt
E. 062 deg 011 nm
F. 141 deg 091 kt
G. 062 deg 014 nm
H. EXTRAP 984 mb
I. 8 C/ 3053 m
J. 15 C/ 3039 m
K. 7 C/ NA
L. CLOSED WALL
M. C20
N. 12345/ 7
O. 0.02 / 2 nm
P. AF307 0207A GUSTAV OB 16
MAX FL WIND 91 KT NE QUAD 0733 Z
RADAR DEPICTED RAGGED EDGE EYEWALL, VARIABLE 20-25 NM,
ADDITIONAL INNER BAND WSW-N
MAX FL TEMP 17 C 234 / 7 NM FROM FL CNTR

Pressure 984mb (extrapolated)
Closed, circular eyewall 20 nm in diameter
Max FL wind in NE quad 91kt.
Max FL temp 7nm SW of center

[RL3AO]

Derek, anything to note from that VDM?

[Derek Ortt]

if the temp max can co-locate with the pressure min, then we will have some RI

[RL3AO]

Movement between VDMs of 333 at 10kt.

[KWT]

This is looking very impressive, the development of the eye seems to have allowed Gustav to really power up and no doubt this is upto 75kts now IMO.

Track looks like taking this over some of the highest heat content in the basin, there is no reason why this won't be the big one this season....

The thing I'd watch is for the models to shift even further west to the point where the Yucatan could come into play, would only need a small delay in the NW motion from the GFDL and you've got a cat-4/5 hurricane near them.

[RL3AO]

NHC now forecasting a category 3.

GUSTAV HAS CONTINUED TO INTENSIFY DURING THE LATE NIGHT HOURS. AN
AIR FORCE RESERVE RECONNAISSANCE MISSION HAS FOUND FLIGHT-LEVEL
WINDS OF 90 KT...PEAK SFMR SURFACE WINDS OF 76 KT...AND A RECENT
ESTIMATED PRESSURE OF 984 MB. THE INITIAL INTENSITY IS
CONSERVATIVELY RAISED TO 75 KT. SATELLITE IMAGES SHOW AN ORGANIZING
PATTERN WITH A CENTRAL DENSE OVERCAST BECOMING MORE PROMINENT AND
GUSTAV IS LIKELY NOT DONE INTENSIFYING BEFORE IT PASSES OVER
SOUTHWESTERN HAITI LATER TODAY. SOME WEAKENING IS SHOWN IN 24 HR
DUE TO THE LAND INTERACTION WITH HAITI. THEREAFTER...THE HURRICANE
IS FORECAST TO BE OVER EXTREMELY WARM WATERS WITH RELATIVELY LIGHT
SHEAR. THE OFFICIAL INTENSITY FORECAST IS INCREASED AND NOW CALLS
FOR GUSTAV TO BE A MAJOR HURRICANE IN THE NORTHWESTERN CARIBBEAN
SEA. IT IS WORTH NOTING THAT BOTH THE GFDL/HWRF FORECAST SHOW AN
EVEN STRONGER HURRICANE. MOST INDICATIONS ARE THAT GUSTAV WILL BE
AN EXTREMELY DANGEROUS HURRICANE IN THE NORTHWESTERN CARIBBEAN SEA
IN A FEW DAYS.

[RL3AO]

Its pretty obvious, but that looks like trouble.

[KWT]

Yep and even that may well be conservative according to the models...

I think Haiti will disrupt this quite well to the point where it will take a good day to reorganise itself but when it does south of Cuba its got primed waters and with this being such a small system I just can't see why this won't be a powerful cat-4/5 to be honest...

[Thunder44]

Just want to rant a bit. I was watching Jeff Morrow on TWC. He kept refering to the clear spot on infrared imagery, as an "eye-like feature" and he was hesitant to call it an eye. But this is already a hurricane and the recon is reporting back a closed eye. What's the issue, Jeff?

[jlauderdal]

Yep and even that may well be conservative according to the models...

I think Haiti will disrupt this quite well to the point where it will take a good day to reorganise itself but when it does south of Cuba its got primed waters and with this being such a small system I just can't see why this won't be a powerful cat-4/5 to be honest...

on the forecast track or even a shift to the left which sounds likely there is no reason to think it wont be a 4, at least...tough to make 5's so predicting one is risky

[KWT]

Yeah thats true but if theres one region of the basin that has produced cat-5's more often then any its the NW Caribbean and given it will be pretty developed anyway by that time its certainly an option though for now cat-4 probably is the most likely option.

[wxman57]

NHC track looks a lot like my track from yesterday afternoon now, though a little slower. I have it to 25N by the 120hr point. They just now see the ridge over the Bahamas (per discussion)?

[KWT]

So wxman57 does the GFDL look good to you at least in terms of track?

If so then this looks like being the 'big' one of the season.

Even with its first landfall I really do think this could get retired, a hurricane hitting Haiti, esp one that is undergoing some decent strengthening is never a good thing.

[wxman57]

So wxman57 does the GFDL look good to you at least in terms of track?

If so then this looks like being the 'big' one of the season.

Even with its first landfall I really do think this could get retired, a hurricane hitting Haiti, esp one that is undergoing some decent strengthening is never a good thing.

GFS is indicating a stronger ridge than yesterday now. I'm beginning to wonder if my first track to the Yucatan Peninsula wasn't so bad. But this hurricane does look like trouble for the Gulf. Better get to work fast. Later...

Oh, an GFDL takes it to 141kts now. Yikes!

[Cyclenall]

I believe this is the first time since Ernesto of 2006 that a major hurricane was forecast to be in the Gulf of Mexico. It's game time (or worry time for those living on or near the coast).

Oh, an GFDL takes it to 141kts now. Yikes!

Doesn't it take it to 158 knots at one point?

[KWT]

Very interesting thoughts, the models have indeed shifted southward again so quite possible the Yucatan will at the very least take a major brush with this system, possibly hit directly by it who knows?

also yep the GFDL really does make this a powerful hurricane, both the GFDL and HWRF have this sub-910mbs at peak

[vaffie]

Latest pressure = 982.2 mb

055500 1652N 07137W 6967 03040 9855 +151 +066 130006 008 023 001 00

073530 1707N 07143W 6967 03023 9838 +150 +066 174003 004 039 002 03

092700 1717N 07156W 6971 03011 9822 +159 +066 049008 009 018 003 03

in the past 1 hr 40 minutes = drop of 1.7 mb
in the previous 1 hr 52 minutes = drop of 1.6 mb
in the last 3 hr 32 minutes = drop of 3.3 mb = 0.94 mb/hr

Conclusion: We have consistently been seeing a drop of just under 1 mb/hr intensification, with a possible speeding up of the process in the past hour to now just over 1.

[KWT]

Yep Vaffie its still ramping up, i'd have thought this process will slow though soon given its now getting closer to Haiti unless its inner core is that tight that it goes on strengthening right upto landfall.

Looks like this could be a top end cat-1 by the time it makes landfall, maybe even borderline cat-2?

I dread to think what will happen in terms of rainfall and damage to Haiti.

[Texas Snowman]

http://weather.chron.com/auto/chron/tro ... climo.html

This is a link to the Sci Guy in the Houston Chron, shows a historical map of August 'canes in about Gustav's position.

Pretty much in line with where the models are trending.

Two pretty interesting things jump out at me: 1) Louisiana isn't hit by any of these, Texas and NW Florida are; 2) look at the dates of these storms, many are very early on either side of the the 1900 line.