ATL: GORDON - Post-Tropical

[Steve]

since last fix, almost a due west movement?

Pressure is up. It looks like this may of peaked already. Just my opinion. Still be on guard.

What criteria are you considering peaked? Pressure? Wind? Hypothetical impacts? Seems as though the peak will come around landfall to me, but I’m willing to place a wager based on at least two of those scenarios.

[bella_may]

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Shortwave IR: http://weather.cod.edu/satrad/exper/?parms=subregional-Florida-07-48-1-100-1&checked=map&colorbar=undefined

What gets my immediate attention is the nasty stuff pushing west from AL into MS along the coast. It's moving at a pretty good clip.

Yeah pretty heavy band just passed over me

[tolakram]

The ULL to the south of Gordon has gotten closer. Both the Euro and GFS forecast this to move southwest eventually.

GFS: https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=atl&pkg=uv200&runtime=2018090318&fh=0

Euro: https://weather.us/model-charts/euro/usa-east/relative-vorticity-300mb/20180904-0300z.html

Here's the COD water vapor loop where you can see the ULL has moved northwest over the last few hours.

http://weather.cod.edu/satrad/exper/?parms=regional-gulf-08-200-1-10-1&checked=map&colorbar=undefined

In short, in my opinion, the upper level environment is a mess and hard to predict if Gordon is going to find decent conditions or not.

[tarheelprogrammer]

since last fix, almost a due west movement?

Pressure is up. It looks like this may of peaked already. Just my opinion. Still be on guard.

What criteria are you considering peaked? Pressure? Wind? Hypothetical impacts? Seems as though the peak will come around landfall to me, but I’m willing to place a wager based on at least two of those scenarios.

Pressure possibly. Wind is likely peaked as well. I could be wrong obviously as it is just my opinion. It is struggling right now. WV is showing this due to dry air and placement close to the ULL to its SW.

[Hammy]

Pressure is up. It looks like this may of peaked already. Just my opinion. Still be on guard.

What criteria are you considering peaked? Pressure? Wind? Hypothetical impacts? Seems as though the peak will come around landfall to me, but I’m willing to place a wager based on at least two of those scenarios.

Pressure possibly. Wind is likely peaked as well. I could be wrong obviously as it is just my opinion. It is struggling right now. WV is showing this due to dry air and placement close to the ULL to its SW.

There's not really any dry air present. I'm wondering if a combination of the forward speed and convection to the east is disrupting the low level convergence to some degree.

[Sciencerocks]

503
URNT15 KNHC 040112
AF305 0307A GORDON HDOB 26 20180904
010230 2522N 08437W 8428 01599 0133 +163 +137 195002 003 018 000 00
010300 2522N 08435W 8427 01601 0135 +162 +140 205001 003 017 001 00
010330 2522N 08433W 8425 01602 0135 +160 +143 242003 004 016 001 00
010400 2522N 08431W 8425 01602 0136 +158 +148 219004 004 017 001 00
010430 2522N 08430W 8425 01604 0137 +158 +150 231004 004 015 002 00
010500 2522N 08428W 8427 01602 0138 +158 +147 218004 005 017 001 00
010530 2522N 08426W 8429 01600 0138 +160 +146 218003 004 018 001 00
010600 2522N 08424W 8428 01601 0137 +157 +149 221004 005 018 001 00
010630 2523N 08422W 8424 01605 0135 +160 +154 212006 007 017 000 00
010700 2523N 08420W 8428 01600 //// +159 //// 205007 007 016 001 01
010730 2523N 08419W 8428 01600 //// +157 //// 211006 009 016 002 01
010800 2523N 08417W 8423 01605 //// +156 //// 217007 007 015 002 01
010830 2523N 08415W 8425 01604 0136 +159 +154 220007 007 017 001 00
010900 2523N 08413W 8426 01602 0137 +160 +156 212008 009 018 001 01
010930 2523N 08411W 8427 01601 0136 +162 +149 221009 009 017 001 00
011000 2523N 08409W 8426 01605 0136 +162 +154 223009 010 016 001 00
011030 2523N 08407W 8426 01605 0137 +160 +157 214009 009 013 002 00
011100 2523N 08406W 8425 01605 0136 +160 +155 208009 010 015 002 01
011130 2523N 08404W 8427 01604 0137 +159 +155 205010 011 017 001 00
011200 2524N 08402W 8426 01604 0136 +160 +150 205011 012 018 001 00
$$
;

[GCANE]

 https://twitter.com/TheAstroNick/status/1036784013929836545

[Javlin]

The ULL to the south of Gordon has gotten closer. Both the Euro and GFS forecast this to move southwest eventually.

GFS: https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=atl&pkg=uv200&runtime=2018090318&fh=0

Euro: https://weather.us/model-charts/euro/usa-east/relative-vorticity-300mb/20180904-0300z.html

Here's the COD water vapor loop where you can see the ULL has moved northwest over the last few hours.

http://weather.cod.edu/satrad/exper/?parms=regional-gulf-08-200-1-10-1&checked=map&colorbar=undefined

In short, in my opinion, the upper level environment is a mess and hard to predict if Gordon is going to find decent conditions or not.

Yeah I mentioned last night how that ULL was making a run SSW hard last night and expected it to be S of Cuba by midday but it turned around ??

[GCANE]

LA Parrishes and New Orleans declaring states of emergency

[wx98]

Made the comment yesterday that forward speed would have an impact on organization/intensity. That indeed seems to be playing out so far...

If it slowed down to about 6 or 7 knots it would be a different story.

[Steve]

Pressure is up. It looks like this may of peaked already. Just my opinion. Still be on guard.

What criteria are you considering peaked? Pressure? Wind? Hypothetical impacts? Seems as though the peak will come around landfall to me, but I’m willing to place a wager based on at least two of those scenarios.

Pressure possibly. Wind is likely peaked as well. I could be wrong obviously as it is just my opinion. It is struggling right now. WV is showing this due to dry air and placement close to the ULL to its SW.

I think most of the models that showed it developing had it strongest around landfall in Mississippi with pressure falling. Winds were to peak on NHC later tomorrow. Idk. I was/am willing to bet a 25.00 donation that the pressure will be lower than 1004 and winds will be higher than 59. You might be right though.

[MississippiWx]

Center is now exposed. It’s outrunning its convection. Hard for anything to strengthen when this happens.

[NDG]

The ULL to the south of Gordon has gotten closer. Both the Euro and GFS forecast this to move southwest eventually.

GFS: https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=atl&pkg=uv200&runtime=2018090318&fh=0

Euro: https://weather.us/model-charts/euro/usa-east/relative-vorticity-300mb/20180904-0300z.html

Here's the COD water vapor loop where you can see the ULL has moved northwest over the last few hours.

http://weather.cod.edu/satrad/exper/?parms=regional-gulf-08-200-1-10-1&checked=map&colorbar=undefined

In short, in my opinion, the upper level environment is a mess and hard to predict if Gordon is going to find decent conditions or not.

Yeah I mentioned last night how that ULL was making a run SSW hard last night and expected it to be S of Cuba by midday but it turned around ??

If anything I think the ULLs to its SW and the one to the north retrograding westward with it is helping pushing the northerly shear that is over the central GOM towards the west out of the way of Gordon as clearly seen below compared to 24 hrs ago. Its fast westerly motion is what's preventing currently from strengthening any further in the short term, is having a hard time getting a nice inflow, IMO.

[Highteeld]

Not sure if tropical storm or giant "7"

[stormhunter7]

coc is clearly exposed now on satellite.

[Javlin]

The ULL to the south of Gordon has gotten closer. Both the Euro and GFS forecast this to move southwest eventually.

GFS: https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=atl&pkg=uv200&runtime=2018090318&fh=0

Euro: https://weather.us/model-charts/euro/usa-east/relative-vorticity-300mb/20180904-0300z.html

Here's the COD water vapor loop where you can see the ULL has moved northwest over the last few hours.

http://weather.cod.edu/satrad/exper/?parms=regional-gulf-08-200-1-10-1&checked=map&colorbar=undefined

In short, in my opinion, the upper level environment is a mess and hard to predict if Gordon is going to find decent conditions or not.

Yeah I mentioned last night how that ULL was making a run SSW hard last night and expected it to be S of Cuba by midday but it turned around ??

If anything I think the ULLs to its SW and the one to the north retrograding westward with it is helping pushing the northerly shear that is over the central GOM towards the west out of the way of Gordon as clearly seen below compared to 24 hrs ago. Its fast westerly motion is what's preventing currently from strengthening any further in the short term, is having a hard time getting a nice inflow, IMO.

The one to the SW I would bet is causing the W movement some I think? it was Claudette that made a L/hook in the GOM into TX over and around the ULL.This has been a year with alot of ULL about.

[1900hurricane]

The worst shear is actually coming from the south due to an upper low off the W tip of Cuba.

[stormhunter7]

NOAA42 returned home earlier, apparently has some mechanical issues and could not continue mission. AF is still out.

[Steve]

Rain echoes on the NGulf are moving just north of due west where as they had been moving out of the SE to the NW all weekend. You’d expect that on the east side of a low, but I think there’s a northern cap somewhere in order to have this movement rather than WNW. Just something to note.

https://www.weather.gov/lix/

[stormhunter7]