Tropical Depression #9
Discussion #1 - This is not an official product -
7:30 pm EDT - Stormsfury
Tropical Depression #9 earlier today quickly flared up and spun up a suspected LLC. Convection has been on the wane recently, however, an upper-level high is parked right over #9 - which is clearly evident on WV imagery. The moisture field is expanding above the depression. In regards to short term intensity, expect #9 to remain a depression unless a new flareup of convection occurs later tonight, or if found not to have an LLC. If #9 doesn't have an LLC right now, it soon will.
Shear is low, and there's a high oceanic heat potential and content and it's heading increasingly towards warmer SST's.
Now in regards to track. In the short term, the models are pretty tightly clustered in bringing the system over the Western Tip of Haiti and Eastern Cuba. After that, uncertainty in regards to later in the period whether a ridge sets up over the East Coast States or not. That will greatly influence the future track of #9 whether it'll become a GOM threat or an EC threat.
Right now, it's way too early to speculate beyond 3 days whether this will become a threat to the GOM or the EC and how strong of a storm that could potentially develop, but residents in Southeastern Florida at this time need to make some preparations for a potential storm in the next 4/5 days and not be caught off-guard.
Brief overview discussion of possible scenarios.
1) The progged ridge along the East Coast to develop about 4/5 days out. If this progged ridge develops as progged, the system after being pulled NW or NNW would possibly be shunted back to the west as the depression or whatever form #9 is in would be bypassed by the exiting trough off the Eastern Seaboard.
2) The ridge doesn't develop or is a lot weaker than progged. #9 could become more of an EC threat or move out to sea altogether. However, IMO, scenario #2 doesn't seem likely at this point.
SF
Discussion of #9.
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- Stormsfury
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Discussion of #9.
Last edited by Stormsfury on Thu Aug 21, 2003 6:40 pm, edited 1 time in total.
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- wxman57
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GFDL
I think scenario #1 looks very likely. Latest GFDL (below) is in line with SE FL threat.
<pre>INITIAL TIME 18Z AUG 21
DISCLAIMER ... THIS INFORMATION IS PROVIDED AS GUIDANCE. IT
REQUIRES INTERPRETATION BY HURRICANE SPECIALISTS AND SHOULD
NOT BE CONSIDERED AS A FINAL PRODUCT. PLEASE SEE THE TPC/NHC
OFFICIAL FORECAST.
FORECAST STORM POSITION
HOUR LATITUDE LONGITUDE HEADING/SPEED(KT)
0 14.4 65.8 290./ 9.9
6 14.8 66.8 293./10.8
12 15.3 67.8 295./10.6
18 15.9 69.3 293./15.5
24 16.6 70.4 304./12.7
30 16.9 71.5 283./10.6
36 17.4 72.2 304./ 8.6
42 18.0 72.9 310./ 9.3
48 18.9 73.5 324./10.3
54 19.6 73.9 335./ 8.8
60 20.1 74.5 307./ 7.5
66 20.7 75.2 312./ 8.5
72 21.1 75.5 327./ 4.9
78 21.5 75.5 351./ 3.2
84 22.0 75.8 329./ 5.8
90 22.6 76.2 334./ 7.3
96 23.2 76.6 322./ 7.5
102 23.7 76.9 333./ 5.3
108 24.1 77.5 301./ 6.6
114 24.7 78.2 312./ 8.7
120 25.1 78.9 299./ 7.6
126 25.5 79.4 311./ 6.2 </pre>
<pre>INITIAL TIME 18Z AUG 21
DISCLAIMER ... THIS INFORMATION IS PROVIDED AS GUIDANCE. IT
REQUIRES INTERPRETATION BY HURRICANE SPECIALISTS AND SHOULD
NOT BE CONSIDERED AS A FINAL PRODUCT. PLEASE SEE THE TPC/NHC
OFFICIAL FORECAST.
FORECAST STORM POSITION
HOUR LATITUDE LONGITUDE HEADING/SPEED(KT)
0 14.4 65.8 290./ 9.9
6 14.8 66.8 293./10.8
12 15.3 67.8 295./10.6
18 15.9 69.3 293./15.5
24 16.6 70.4 304./12.7
30 16.9 71.5 283./10.6
36 17.4 72.2 304./ 8.6
42 18.0 72.9 310./ 9.3
48 18.9 73.5 324./10.3
54 19.6 73.9 335./ 8.8
60 20.1 74.5 307./ 7.5
66 20.7 75.2 312./ 8.5
72 21.1 75.5 327./ 4.9
78 21.5 75.5 351./ 3.2
84 22.0 75.8 329./ 5.8
90 22.6 76.2 334./ 7.3
96 23.2 76.6 322./ 7.5
102 23.7 76.9 333./ 5.3
108 24.1 77.5 301./ 6.6
114 24.7 78.2 312./ 8.7
120 25.1 78.9 299./ 7.6
126 25.5 79.4 311./ 6.2 </pre>
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The cold front moving through the central United States (including David's location) is forecast into the southeastern U.S. and stall across Georgia. Depending on how far south this front gets will be important to the eventual track of the tropical cyclone.
A high pressure system behind a cold front over the U.S. moves storms westward, like Claudette and Erika. However, just like tropical systems move north and/or northeastward ahead of cold fronts up the eastern seaboard into southern New England (like Gloria in 1985 and Bob in 1991)... a storm ahead of a west/east oriented cold front across the southeastern United States would have to move eastward.
This will indeed be very very interesting and important to monitor in the coming days.
A high pressure system behind a cold front over the U.S. moves storms westward, like Claudette and Erika. However, just like tropical systems move north and/or northeastward ahead of cold fronts up the eastern seaboard into southern New England (like Gloria in 1985 and Bob in 1991)... a storm ahead of a west/east oriented cold front across the southeastern United States would have to move eastward.
This will indeed be very very interesting and important to monitor in the coming days.
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Hey wxman57,
The last couple of days I've seen your posts mentioning the GFDL. Do you give that model extra creedence or something? I know it's the hurricane model, but outside of 1 or 2 storms last year, I've never thought it did all that great of a job. It is particularly weak (meaning bad, not biased) when it comes to intensity, but I watch tons of its runs for the EPAC and the Atlantic. It does really strange things from run to run. I put little faith and no trust in it.
However, you are a professional met, so that's why I'm asking you for your opinion. Thanks.
Steve
The last couple of days I've seen your posts mentioning the GFDL. Do you give that model extra creedence or something? I know it's the hurricane model, but outside of 1 or 2 storms last year, I've never thought it did all that great of a job. It is particularly weak (meaning bad, not biased) when it comes to intensity, but I watch tons of its runs for the EPAC and the Atlantic. It does really strange things from run to run. I put little faith and no trust in it.
However, you are a professional met, so that's why I'm asking you for your opinion. Thanks.
Steve
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I'm going to take another chance by bumping it up to the top. Just so that everyone is clear, I think the GFDL is pretty useless, but when I see a weatherperson playing it up or noting it, I'm going to ask.
The most recent run I've seen essentially stalls the system for like 5 days after 24 hours. Now I'm not saying that can't happen, but compared to previous runs, it's ALL OVER THE PLACE. Hence, my opinion is that eventually it will get a track right by default.
So wxman, tell me what is there to like about the GFDL.
Thanks,
Steve
The most recent run I've seen essentially stalls the system for like 5 days after 24 hours. Now I'm not saying that can't happen, but compared to previous runs, it's ALL OVER THE PLACE. Hence, my opinion is that eventually it will get a track right by default.
So wxman, tell me what is there to like about the GFDL.
Thanks,
Steve
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The latest run doesn't stall it...it takes it towards the SE GOM. Remember that the little window on the side is the storm relative window. What you are seeing the GFDL do is keep this system weak until it hits the DR...then track it wnw over cuba. In other words...due to the interaction with land it dissipates the system. Since it doesn't have a low to focus on...the storm relative window stays focused on thas last place it had one. It doesn't stall it. If you will look at the window to the left (if you are looking at the PSU site)...you will see it tracks the remnants of td9 into the Gom by day 5 after going over Hispaniola and Cuba.
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Thanks AF. I was actually looking at the raw data which I NEVER do except when they release the tropical model text at OSU. So since it doesn't really have anything there, it just basically moseys around in that same general loocation I guess. But the lats/longs change a bit (btw, I think it was the 0z or 6z that I saw the text).
Steve
Steve
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http://met.psu.edu/tropical/tcgengifs/
If you look at the loop you will see the wave headed wnw. IMO...if it tracks over the islands the GFDl will be right because there won't be much left to upgrade. If the remanant hold together it may get into the GOm and redevelop. The best chance 9 has is to move south of the islands. Right now...I think it is headed down the middle or just to the right.
If you look at the loop you will see the wave headed wnw. IMO...if it tracks over the islands the GFDl will be right because there won't be much left to upgrade. If the remanant hold together it may get into the GOm and redevelop. The best chance 9 has is to move south of the islands. Right now...I think it is headed down the middle or just to the right.
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