ATL: FRED - Post-Tropical - Discussion

[Shell Mound]

The vortex isn't closed yet looking at the airborne radar data (I don't think I have permission to share this). There is also some tilting of the vortex, as the mid-level vortex is displaced to the southwest of the low-level center. The low-level vortex is also quite weak.

Wouldn’t this indicate easterly mid-level shear and thus faster-than-normal forward speed? I have said all along that PTC Six is very reminiscent of Elsa.

[alienstorm]

Looking at the San Juna radar the potential LLC is at ~ 16.9N 64.4W

http://moe.met.fsu.edu/~mnissenbaum/RadarArchive/TJUA/loop.html

[SouthDadeFish]

The vortex isn't closed yet looking at the airborne radar data (I don't think I have permission to share this). There is also some tilting of the vortex, as the mid-level vortex is displaced to the southwest of the low-level center. The low-level vortex is also quite weak.

Wouldn’t this indicate easterly mid-level shear and thus faster-than-normal forward speed? I have said all along that PTC Six is very reminiscent of Elsa.

Theoretically, it's possible, although model analyses don't really show prominent mid-level shear. Could also be the result of dry-air intrusions combining with weak shear. I wouldn't necessarily say the system is moving too fast for development though. Elsa was moving much faster than PTC6.

[Cat5James]

Slower forward movement of the storm is allowing more time for the weakness in the ridge over FL, leading to the eventual northward turn farther east.

[Shell Mound]

 https://twitter.com/HurricanesJames/status/1425144776429613063




Couldn’t this slower movement also indicate a weaker TUTT that would allow for a deeper PTC Six to become more vertically stacked in the Bahamas?

In other words, when a TUTT is deeper, wouldn’t the low-level trades tend to strengthen in its immediate vicinity, thereby preventing LL convergence?

[AutoPenalti]

https://twitter.com/HurricanesJames/status/1425144776429613063

Couldn’t this slower movement also indicate a weaker TUTT that would allow for a deeper PTC Six to become more vertically stacked in the Bahamas?

In other words, when a TUTT is deeper, wouldn’t the low-level trades tend to strengthen in its immediate vicinity, thereby preventing LL convergence?

That ULL over Florida as Levi pointed out has been sitting there for days. Over time, the ULL weakens and moves away aiding to a lower shear environment.

[Shell Mound]

https://twitter.com/HurricanesJames/status/1425144776429613063

Couldn’t this slower movement also indicate a weaker TUTT that would allow for a deeper PTC Six to become more vertically stacked in the Bahamas?

In other words, when a TUTT is deeper, wouldn’t the low-level trades tend to strengthen in its immediate vicinity, thereby preventing LL convergence?

That ULL over Florida as Levi pointed out has been sitting there for days. Over time, the ULL weakens and moves away aiding to a lower shear environment.

I was alluding to the fact that models have trended toward a slower PTC Six and am wondering whether those models are also envisaging a weaker ULL pre-Florida.

[InfernoFlameCat]

If this manages to get into the gulf for more than a day that could spell serious trouble. Conditions are looking to be perfect there with 88 F water. Not good. This is unlikely to occur but bears consideration.

[abajan]

[youtube]https://youtu.be/LQzmCrZ6BUw[/youtube]

[Nimbus]

The mid levels are elongated so it could reform north of Hispaniola if it doesn't split.
Doubt it will shoot the Mona Passage as cleanly as the 12Z HWRF forecasts.
12Z HWRF doom stuff at 93 hours.

[InfernoFlameCat]

The mid levels are elongated so it could reform north of Hispaniola if it doesn't split.
Doubt it will shoot the Mona Passage as cleanly as the 12Z HWRF forecasts.
12Z HWRF doom stuff at 93 hours.

https://www.tropicaltidbits.com/analysis/models/hwrf/2021081012/hwrf_mslp_uv850_06L_32.png

Cat 3 bro it wants a cat 3. Lol

[Shell Mound]

The mid levels are elongated so it could reform north of Hispaniola if it doesn't split.
Doubt it will shoot the Mona Passage as cleanly as the 12Z HWRF forecasts.
12Z HWRF doom stuff at 93 hours.

https://www.tropicaltidbits.com/analysis/models/hwrf/2021081012/hwrf_mslp_uv850_06L_32.png

Cat 3 bro it wants a cat 3. Lol

It shows landfall over Fort Lauderdale as a Category 2.

[InfernoFlameCat]

The mid levels are elongated so it could reform north of Hispaniola if it doesn't split.
Doubt it will shoot the Mona Passage as cleanly as the 12Z HWRF forecasts.
12Z HWRF doom stuff at 93 hours.

https://www.tropicaltidbits.com/analysis/models/hwrf/2021081012/hwrf_mslp_uv850_06L_32.png

Cat 3 bro it wants a cat 3. Lol

It shows landfall over Fort Lauderdale as a Category 2.

Oh I see he played that at 850mb

[Visioen]

What amazes me is how the plane is flying upside down.

Maybe the circulation center is @16.5-16.9N/62.5-63W?

Sorry

[tolakram]

What amazes me is how the plane is flying upside down.

https://i.imgur.com/aI7UAgU.png

Maybe the circulation center is @16.5-16.9N/62.5-63W?

Sorry

I was going to make a similar comment. It seems like the plane graphic is broken this year.

[AutoPenalti]

What amazes me is how the plane is flying upside down.

https://i.imgur.com/aI7UAgU.png

Maybe the circulation center is @16.5-16.9N/62.5-63W?

Sorry

I was going to make a similar comment. It seems like the plane graphic is broken this year.

Well how else will it do dropsondes?

[skyline385]

12Z HWRF stronger than last run but probably still very inaccurate as the system still doesn't have a well defined center and recon just got the data to feed in for the next runs...

The 12Z HWRF assimilated the recon data. It's initialization looked quite reasonable to me. Shows a tilted vortex. However, the rest of the run is debatable. I wouldn't totally rule it out, but it doesn't seem like the most likely scenario.

12Z HWRF starts running at around 6Z though, the recon plane was nowhere near it at that time...

[AutoPenalti]

12Z HWRF stronger than last run but probably still very inaccurate as the system still doesn't have a well defined center and recon just got the data to feed in for the next runs...

The 12Z HWRF assimilated the recon data. It's initialization looked quite reasonable to me. Shows a tilted vortex. However, the rest of the run is debatable. I wouldn't totally rule it out, but it doesn't seem like the most likely scenario.

12Z HWRF starts running at around 6Z though, the recon plane was nowhere near it at that time...

I'm not sure this has recon data yet...

[skyline385]

The 12Z HWRF assimilated the recon data. It's initialization looked quite reasonable to me. Shows a tilted vortex. However, the rest of the run is debatable. I wouldn't totally rule it out, but it doesn't seem like the most likely scenario.

12Z HWRF starts running at around 6Z though, the recon plane was nowhere near it at that time...

I'm not sure this has recon data yet...

It doesnt that's what i said in my original post

[Chemmers]

Look like it is trying to wrap up, think will see the pressure drop soon