ATL: GORDON - Post-Tropical
Moderator: S2k Moderators
-
- S2K Supporter
- Posts: 2772
- Joined: Fri Aug 29, 2003 10:52 am
- Location: Biloxi Beach, Ms
- Contact:
Re: ATL: INVEST 91L - Discussion
GFS is weaker but basic same track give or take a few miles, quite underwhelming all in all...
1 likes
- MississippiWx
- S2K Supporter
- Posts: 1696
- Joined: Sat Aug 14, 2010 1:44 pm
- Location: Hattiesburg, Mississippi
Re: ATL: INVEST 91L - Discussion
GFS continues with its back and forth ways on strength. 12z came in with another weak run. Personally, I believe it's difficult to look at visible satellite imagery, and not believe this is coming together pretty fast. It is fairly small, so it could be susceptible to rapid development. That also makes it susceptible to being torn apart by shear if it makes a wrong move.
Have to wonder if a PTC tag will be placed on this soon due to its proximity to the Bahamas and Florida.
Have to wonder if a PTC tag will be placed on this soon due to its proximity to the Bahamas and Florida.
1 likes
This post is not an official forecast and should not be used as such. It is just the opinion of MississippiWx and may or may not be backed by sound meteorological data. It is not endorsed by any professional institution including storm2k.org. For Official Information please refer to the NHC and NWS products.
Re: ATL: INVEST 91L - Discussion
MississippiWx wrote:GFS continues with its back and forth ways on strength. 12z came in with another weak run. Personally, I believe it's difficult to look at visible satellite imagery, and not believe this is coming together pretty fast. It is fairly small, so it could be susceptible to rapid development. That also makes it susceptible to being torn apart by shear if it makes a wrong move.
Have to wonder if a PTC tag will be placed on this soon due to its proximity to the Bahamas and Florida.
Which is why I keep commenting on the existing shear in the Eastern GoM, which has been steadily increasing. It's supposed to move in tandem with 91L, but so far it hasn't really budged. Is that what the GFS is picking up on?
0 likes
Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.
Re: ATL: INVEST 91L - Discussion
It does not matter if it is named or classified as a PTC before impacting Florida. An afternoon thunderstorm in Florida can be more powerful(in a small area) than a weak tropical storm. I have experienced 50kt+ winds while boating countless times as a result of an afternoon thunderstorm.
Classifying unnecessarily this will only cause hype and scare tourists away. However I do feel that coastal Louisiana and Mississippi need to watch this closely because of the RI potential once this makes it to the gulf.
Classifying unnecessarily this will only cause hype and scare tourists away. However I do feel that coastal Louisiana and Mississippi need to watch this closely because of the RI potential once this makes it to the gulf.
1 likes
-
- Category 5
- Posts: 2434
- Age: 32
- Joined: Thu Sep 07, 2017 3:39 pm
- Location: St. Petersburg, FL → Scandinavia
Re: ATL: INVEST 91L - Discussion
SoupBone wrote:MississippiWx wrote:GFS continues with its back and forth ways on strength. 12z came in with another weak run. Personally, I believe it's difficult to look at visible satellite imagery, and not believe this is coming together pretty fast. It is fairly small, so it could be susceptible to rapid development. That also makes it susceptible to being torn apart by shear if it makes a wrong move.
Have to wonder if a PTC tag will be placed on this soon due to its proximity to the Bahamas and Florida.
Which is why I keep commenting on the existing shear in the Eastern GoM, which has been steadily increasing. It's supposed to move in tandem with 91L, but so far it hasn't really budged. Is that what the GFS is picking up on?
In my humble view, the GFS is simply incorrect. A look at the shear charts on the 12Z run shows that it actually depicts a more favourable environment than previous runs (e.g., 00Z) did, with strong hints of a dual outflow channel starting to show up as 91L moves over/near the Keys and the southernmost FL peninsula. The upper low is clearly moving out of the way on the latest water-vapor imagery—it certainly is allowing sufficient room for 91L to organise. Therefore, I strongly suspect that the GFS is underestimating the intensity of 91L. The shear charts that you mention indicate short-term increases in shear over the Gulf as the upper low moves over the area. It is not a permanent trend. Watch shear decrease overnight as the upper low retrogrades.
5 likes
CVW / MiamiensisWx / Shell Mound
The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the NHC and NWS.
-
- Category 5
- Posts: 21238
- Age: 42
- Joined: Sun Sep 19, 2004 9:58 pm
- Location: Ready for the Chase.
- Contact:
Re: ATL: INVEST 91L - Discussion
umm it is pretty hard to imagine there is nothing trying to get going at the surface right now.. especially with radar..
http://barbadosweather.org/Composite/ki ... 1535841761
http://barbadosweather.org/Composite/ki ... 1535841761
4 likes
Note: If I make a post that is brief. Please refer back to previous posts for the analysis or reasoning. I do not re-write/qoute what my initial post said each time.
If there is nothing before... then just ask
Space & Atmospheric Physicist, Embry-Riddle Aeronautical University,
I believe the sky is falling...
If there is nothing before... then just ask

Space & Atmospheric Physicist, Embry-Riddle Aeronautical University,
I believe the sky is falling...
- MississippiWx
- S2K Supporter
- Posts: 1696
- Joined: Sat Aug 14, 2010 1:44 pm
- Location: Hattiesburg, Mississippi
Re: ATL: INVEST 91L - Discussion
JarrodB wrote:It does not matter if it is named or classified as a PTC before impacting Florida. An afternoon thunderstorm in Florida can be more powerful(in a small area) than a weak tropical storm. I have experienced 50kt+ winds while boating countless times as a result of an afternoon thunderstorm.
Classifying unnecessarily this will only cause hype and scare tourists away. However I do feel that coastal Louisiana and Mississippi need to watch this closely because of the RI potential once this makes it to the gulf.
It matters. A potential tropical cyclone is not classifying unnecessarily because it is simply "potential".
Also, it would be nice to get a jump start on advisories to get the NHC's thoughts on track and intensity.
4 likes
This post is not an official forecast and should not be used as such. It is just the opinion of MississippiWx and may or may not be backed by sound meteorological data. It is not endorsed by any professional institution including storm2k.org. For Official Information please refer to the NHC and NWS products.
- MississippiWx
- S2K Supporter
- Posts: 1696
- Joined: Sat Aug 14, 2010 1:44 pm
- Location: Hattiesburg, Mississippi
Re: ATL: INVEST 91L - Discussion
12z CMC has this developing pretty much right away. I think it has a better grasp on this than the GFS due to current trends.
1 likes
This post is not an official forecast and should not be used as such. It is just the opinion of MississippiWx and may or may not be backed by sound meteorological data. It is not endorsed by any professional institution including storm2k.org. For Official Information please refer to the NHC and NWS products.
- Evil Jeremy
- S2K Supporter
- Posts: 5463
- Age: 31
- Joined: Mon Apr 10, 2006 2:10 pm
- Location: Los Angeles, CA
Re: ATL: INVEST 91L - Discussion
JarrodB wrote:It does not matter if it is named or classified as a PTC before impacting Florida. An afternoon thunderstorm in Florida can be more powerful(in a small area) than a weak tropical storm. I have experienced 50kt+ winds while boating countless times as a result of an afternoon thunderstorm.
Classifying unnecessarily this will only cause hype and scare tourists away. However I do feel that coastal Louisiana and Mississippi need to watch this closely because of the RI potential once this makes it to the gulf.
You are applying subjectivity to what should be an objective process. A tropical cyclone is a tropical cyclone, and there's been established precedent for pre-tropical cyclone advisories as well.
1 likes
Frances 04 / Jeanne 04 / Katrina 05 / Wilma 05 / Fay 08 / Debby 12 / Andrea 13 / Colin 16 / Hermine 16 / Matthew 16 / Irma 17
-
- Category 5
- Posts: 21238
- Age: 42
- Joined: Sun Sep 19, 2004 9:58 pm
- Location: Ready for the Chase.
- Contact:
Re: ATL: INVEST 91L - Discussion
at this point I am going with the WRF lol..
Last edited by Aric Dunn on Sun Sep 02, 2018 11:17 am, edited 1 time in total.
0 likes
Note: If I make a post that is brief. Please refer back to previous posts for the analysis or reasoning. I do not re-write/qoute what my initial post said each time.
If there is nothing before... then just ask
Space & Atmospheric Physicist, Embry-Riddle Aeronautical University,
I believe the sky is falling...
If there is nothing before... then just ask

Space & Atmospheric Physicist, Embry-Riddle Aeronautical University,
I believe the sky is falling...
-
- Category 2
- Posts: 571
- Joined: Tue Jun 20, 2017 2:26 pm
Re: ATL: INVEST 91L - Discussion
Is the high pressure not going to be as strong as earlier runs which had Texas?? What is protecting Texas?
0 likes
Re: ATL: INVEST 91L - Discussion
Evil Jeremy wrote:
You are applying subjectivity to what should be an objective process. A tropical cyclone is a tropical cyclone, and there's been established precedent for pre-tropical cyclone advisories as well.
If and only if it meets the criteria. There is no need to classify a tropical just because it is close to land.
I do think this will become a depression and possibly Gordon by tomorrow night.
0 likes
- Clearcloudz
- Category 2
- Posts: 540
- Joined: Sun Jun 10, 2018 1:46 pm
- Location: Rosenberg TX
Re: ATL: INVEST 91L - Discussion
MississippiWx wrote:12z CMC has this developing pretty much right away. I think it has a better grasp on this than the GFS due to current trends.
Initialization was very good so yeah I do believe it has a better grasp of current situation and trends.
0 likes
-
- S2K Supporter
- Posts: 7177
- Joined: Wed May 19, 2004 5:46 am
- Location: NE Fort Lauderdale
- Contact:
Re: RE: Re: ATL: INVEST 91L - Discussion
Nogaps
Sent from my SM-G950U using Tapatalk
Aric Dunn wrote:at this point I am going with the WRF lol..
Sent from my SM-G950U using Tapatalk
1 likes
-
- Category 5
- Posts: 21238
- Age: 42
- Joined: Sun Sep 19, 2004 9:58 pm
- Location: Ready for the Chase.
- Contact:
Re: RE: Re: ATL: INVEST 91L - Discussion
jlauderdal wrote:NogapsAric Dunn wrote:at this point I am going with the WRF lol..
Sent from my SM-G950U using Tapatalk
From the current level of organization .. I would wager on this becoming a TC sooner rather than later.
The shear has dropped to well within a developmental standpoint. not to stop it from now till the gulf..
Last edited by Aric Dunn on Sun Sep 02, 2018 11:25 am, edited 1 time in total.
1 likes
Note: If I make a post that is brief. Please refer back to previous posts for the analysis or reasoning. I do not re-write/qoute what my initial post said each time.
If there is nothing before... then just ask
Space & Atmospheric Physicist, Embry-Riddle Aeronautical University,
I believe the sky is falling...
If there is nothing before... then just ask

Space & Atmospheric Physicist, Embry-Riddle Aeronautical University,
I believe the sky is falling...
Re: ATL: INVEST 91L - Discussion
We will need to start talking about barrier and low lying islands. If it goes, we may not have much time to evacuate them.
1 likes
-
- S2K Supporter
- Posts: 7177
- Joined: Wed May 19, 2004 5:46 am
- Location: NE Fort Lauderdale
- Contact:
Re: RE: Re: RE: Re: ATL: INVEST 91L - Discussion
That seems very reasonable, really need some some mid and low level obs..as you know, we have seen very impressive sat presentations and nada at the surface
Sent from my SM-G950U using Tapatalk
Aric Dunn wrote:jlauderdal wrote:NogapsAric Dunn wrote:at this point I am going with the WRF lol..
Sent from my SM-G950U using Tapatalk
From the current level of organization .. I would wager on this becoming a TC sooner rather than later.
The shear has dropped to well within a developmental standpoint. not to stop it from now till the gulf..
Sent from my SM-G950U using Tapatalk
2 likes
Re: RE: Re: RE: Re: ATL: INVEST 91L - Discussion
jlauderdal wrote:That seems very reasonable, really need some some mid and low level obs..as you know, we have seen very impressive sat presentations and nada at the surfaceAric Dunn wrote:jlauderdal wrote:Nogaps
Sent from my SM-G950U using Tapatalk
From the current level of organization .. I would wager on this becoming a TC sooner rather than later.
The shear has dropped to well within a developmental standpoint. not to stop it from now till the gulf..
Sent from my SM-G950U using Tapatalk
Gotta get that generator going buddy!

0 likes
Re: ATL: INVEST 91L - Discussion
Unfortunately there are no buoys in the vicinity. Tomorrow when this system is over the Keys and S. Florida we will get direct obs.
At the 2pm(edt) update I hope the NHC announces recon flights.
At the 2pm(edt) update I hope the NHC announces recon flights.
0 likes
-
- Category 5
- Posts: 21238
- Age: 42
- Joined: Sun Sep 19, 2004 9:58 pm
- Location: Ready for the Chase.
- Contact:
Re: ATL: INVEST 91L - Discussion
I am watching the convection in this area( red circle ) for their overall motion .. if we see some easterly ( ne , nne, ene etc. ) component to them then it is highly likely we have a developing circ. not guaranteed but given the convective pattern, we have now I would not be surprised.




1 likes
Note: If I make a post that is brief. Please refer back to previous posts for the analysis or reasoning. I do not re-write/qoute what my initial post said each time.
If there is nothing before... then just ask
Space & Atmospheric Physicist, Embry-Riddle Aeronautical University,
I believe the sky is falling...
If there is nothing before... then just ask

Space & Atmospheric Physicist, Embry-Riddle Aeronautical University,
I believe the sky is falling...
Who is online
Users browsing this forum: No registered users and 81 guests