ATL GUSTAV: Tropical Depression - Discussion

[Brent]

Pressure down to 957 mb. Eye still open to the SE.

[Thunder44]

Recon VDM pressure down to 957mb. That's 3mb drop in little less than 2 hours. We'll see if it continues in the next fix.

[stormie]

Anyone know what the winds are here in the Tampa Bay area? Specifically along the beach of Pinellas County. Both peak wind gust and sustained. I'm surprised at how strong they've been.

The winds surprised me, too. I'm in NW Hillsborough County. I just checked the weather station in my backyard, and it had recorded a 55 mph gust.

[jabman98]

We're having a lovely day here in Houston. Winds out of the NNE, generally light with occasional gusts, and low humidity. Pretty pleasant for August.

Just heard a NOLA area official (sorry, didn't catch his name) say they estimate 20-30% of the folks outside NOLA are staying put. People in places like Houma, Terrebonne Parish, Plaquemines Parish, etc. Also folks on the W. side of the lake. He speculated that those people didn't flood like the people in NOLA proper did during Katrina, so they think they're "safe". He and the TV interviewer person tried to urge them all to get out and evacuate as ordered.

I hope they're wrong with their estimations, but it was an official from the area so I kind of think they're not that far off.

[Category 5]

the key to this (given similiar upper level conditons) is a path that

1. takes it over the loop current
2. is moving very fast (after exiting loop current thru landfall)

cat 4's and 5's weaken in the NGOM

threes tend to remain steady

1s and 2s can intensity

dont want to deflect thread.....but then derek what did camile do (or was it just that much stronger prior to landfall)

Camille is a bad example. Remember, we had no recon (they were busy playing with the fishy), and it was 1969 technology.

[rtd2]

Eyewall still open although pressure has dropped

H. 957 mb
I. 14 C/ 3050 m
J. 16 C/ 3045 m
K. 10 C/ NA
L. OPEN SE QUAD

[RL3AO]

UZNT13 KNHC 311947
XXAA 81197 99261 70869 08166 99957 28814 11509 00890 ///// /////
92308 26816 11509 85056 23421 10512 70740 15440 18008 88999 77999
31313 09608 81917
61616 AF304 2207A GUSTAV OB 12
62626 EYE SPL 2608N08690W 1920 MBL WND 11509 AEV 00000 DLM WND 11
010 957708 WL150 11509 080 =
XXBB 81198 99261 70869 08166 00957 28814 11850 23421 22725 17413
33706 16833 44697 14445
21212 00957 11509 11850 10512 22807 12013 33790 08510 44743 11010
55697 18509
31313 09608 81917
61616 AF304 2207A GUSTAV OB 12
62626 EYE SPL 2608N08690W 1920 MBL WND 11509 AEV 00000 DLM WND 11
010 957708 WL150 11509 080 =

Dropsonde: 957mb with a 9kt wind.

[KWT]

Yeah what Derek said is generally what I've noticed as well with gulf of Mexico landfalling systems, cat-3's do tend to hold steady, maybe slow strengthening.

Gustav may do a little more strengthening than normal systems simply because its moving faster into those waters, even then I think the best odds are this staying around the cat-3 range.

My orginal prediciton was 150mph peak, 120mph landfall near Terrabonne, I'm very happy with that call now.

[Texas Snowman]

Dumb question perhaps, but does the forward speed have anything to do with the destructive potential in the right front quadrant?

[CrazyC83]

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This is my thoughts on the best track so far:

Time Lat Long Winds Pres
• 25/0600 14.5 68.5 30 1007 Tropical depression
• 25/1200 15.3 69.5 40 1003 Tropical storm
• 25/1800 15.6 70.5 50 996
• 26/0000 16.3 71.1 60 993
• 26/0600 16.9 71.6 75 986 Hurricane
• 26/1200 17.6 72.2 80 981
• 26/1800 18.2 72.8 70 983
• 27/0000 18.4 73.1 60 992 Tropical storm
• 27/0600 18.6 73.3 50 997
• 27/1200 18.7 73.6 45 997
• 27/1800 18.9 74.0 40 999
• 28/0000 18.7 74.9 35 998
• 28/0600 18.1 75.4 50 990
• 28/1200 17.9 75.7 60 985
• 28/1800 18.0 76.2 65 983 Hurricane
• 29/0000 17.8 76.9 60 987 Tropical storm
• 29/0600 17.9 77.6 55 991
• 29/1200 18.3 78.4 60 987
• 29/1800 18.8 79.2 65 984 Hurricane
• 30/0000 19.2 80.0 75 974
• 30/0600 19.7 80.8 85 966
• 30/1200 20.7 81.6 110 954
• 30/1800 21.6 82.6 125 942
• 31/0000 22.7 83.4 110 949
• 31/0600 23.6 84.4 100 958
• 31/1200 24.8 85.5 95 961
• 31/1800 25.9 86.7 100 957

Landfalls
• 26/1500 17.9 72.6 80 980 Haiti landfall
• 28/1800 18.0 76.2 65 983 Jamaica landfall
• 30/1700 21.3 82.4 125 944 Isle of Youth landfall
• 30/2200 22.3 83.2 120 941 Western Cuba landfall

[deltadog03]

Looking a bit better...My fault today was tracking the MLC...How far are the LLC and MLC dissplaced still??

[caneman]

Anyone know what the winds are here in the Tampa Bay area? Specifically along the beach of Pinellas County. Both peak wind gust and sustained. I'm surprised at how strong they've been.

The winds surprised me, too. I'm in NW Hillsborough County. I just checked the weather station in my backyard, and it had recorded a 55 mph gust.

Yeah, we've got some branches and limbs down. What are we 200 miles away?

[Category 5]

Dumb question perhaps, but does the forward speed have anything to do with the destructive potential in the right front quadrant?

As a matter of fact I believe it does. Theres an equation for it too, I don't know it off the top of my head though. Something with the maximum sustained winds and the forward speed and direction. Perhaps a pro met or someone else knows.

[vaffie]

For those interested, I used the latest recon data to work out it's current trajectory (for the past 98 minutes):

I used 25'51''N, 86'33''W to 26'2''N, 86'54'' and used the FCC website to account for differences in heading dependent upon latitude to get a precise value of:

300.3 degrees at 21.9 knots.
Note that the heading for the previous six hours was an average of 315 degrees at 15 knots.

So it has sped up a little and for the past 1.5 hours has been heading on a more westerly track than prior.

Sped up a LITTLE? if those numbers were accurate it would push landfall WAY up....

Not necessarily. By going on a more westerly path, it would delay landfall substantially. I extrapolated the past 1 hour and a half movement, and it took me to west of the Texas/Louisiana border, an unlikely (but not impossible) event. You have to consider much longer time periods for landfall projections. It will be interesting to examine the next couple recon reports to look at the average.

[rtd2]

Dumb question perhaps, but does the forward speed have anything to do with the destructive potential in the right front quadrant?

Yes foward speed adds to wind speed in RFQ

[shah8]

Convection is still blowing like crazy.

If that shear even lets up just a little bit in the next 4 hours or so...

[ColdFusion]

Dumb question perhaps, but does the forward speed have anything to do with the destructive potential in the right front quadrant?

I think one beneficial effect will be a lot less time for the easterly winds to pile water into the lake and canals.

[jojo]

Would someone mind educating me on this. I see people referring to direction of movement as 280, 300, 275, etc. I know 270-300 is in the WNW to NW but can someone tell me what number signifies W and what number signifies N so I can know what the inbetween numbers mean?

Think of a compass and north is 0 degrees, E is 90 degrees, S is 180, w is 270, etc - that number is just the angle (NW would be 315, WNW 292, etc)

[HarlequinBoy]

Anyone know what the winds are here in the Tampa Bay area? Specifically along the beach of Pinellas County. Both peak wind gust and sustained. I'm surprised at how strong they've been.

The winds surprised me, too. I'm in NW Hillsborough County. I just checked the weather station in my backyard, and it had recorded a 55 mph gust.

That's a bit impressive.

[KWT]

Eyewall still open although pressure has dropped

H. 957 mb
I. 14 C/ 3050 m
J. 16 C/ 3045 m
K. 10 C/ NA
L. OPEN SE QUAD

Yep that is indeed a pressure drop, not all that surprising given the eye did get breifly much more impressive about 1-2hrs ago. Closing back up again as the northern eyewall bursts convection.