ATL: ZETA - Post-Tropical - Discussion

[aspen]

Water vapor imagery shows some very good outflow around Zeta.
https://i.imgur.com/BX7pHvh.png

SSTs are also nice and toasty up until landfall, around 29.5-30C.
https://i.imgur.com/M7evVDR.png

Zeta has a lot to work with once northerly shear dies down and it's able to stack.

And a core to work with, also note on how high the cloud tops are.

Stacking and a core go hand-in-hand. Once Zeta is able to stack, it’ll be able to develop a core, especially if it’ll be firing off convection anywhere as deep as it has been for the last several hours.

[tiger_deF]

For the first time in Zeta's existence I am finally seeing some scant evidence of northerly banding from the massive convective ball. This could potentially indicate that the center is still relocating/migrating to the South, or that upper level conditions have improved somewhat around Zeta over the past several hours.

[Ian2401]

when does next recon go out?

[Iceresistance]

when does next recon go out?

There is still a upper-level recon active right now. They are waiting for that one to land before sending out another one unless there is something up with Zeta.

[ElectricStorm]

when does next recon go out?

There is still a upper-level recon active right now. They are waiting for that one to land before sending out another one unless there is something up with Zeta.

I'm pretty sure the next one goes out at 0330z so about 1030pm central

[SconnieCane]

Can clearly see the center NW of the convection on high-res visible. Max FL wind the plane could find was about 50 kts. Some evidence of a small area of 45kt winds SE of the center. Otherwise, winds generally below TS strength. Struggling with northerly wind shear, though the shear should be decreasing tonight/tomorrow. Hope the long-range GFS is wrong...

Beyond 300 hours we are basically talking about climatological probabilities.
Last Cat 4 storm to devastate southeast Florida was 18 years ago.
Seasonal outlook for 2021 can't take into account the 19 year lull with their probability calculation..

18 years ago would be 2002. I can't recall a devastating SE FL Cat. 4 from that season

[ClarCari]

8PM still stationary slightlyyyyy centered north 18.0°N 83.6°W with same winds but pressure down to 997MB.

[Iceresistance]

Can clearly see the center NW of the convection on high-res visible. Max FL wind the plane could find was about 50 kts. Some evidence of a small area of 45kt winds SE of the center. Otherwise, winds generally below TS strength. Struggling with northerly wind shear, though the shear should be decreasing tonight/tomorrow. Hope the long-range GFS is wrong...

Beyond 300 hours we are basically talking about climatological probabilities.
Last Cat 4 storm to devastate southeast Florida was 18 years ago.
Seasonal outlook for 2021 can't take into account the 19 year lull with their probability calculation..

18 years ago would be 2002. I can't recall a devastating SE FL Cat. 4 from that season

I think it was Andrew in 1992 that was the last storm to make landfall over SE Florida.

[JtSmarts]

Can clearly see the center NW of the convection on high-res visible. Max FL wind the plane could find was about 50 kts. Some evidence of a small area of 45kt winds SE of the center. Otherwise, winds generally below TS strength. Struggling with northerly wind shear, though the shear should be decreasing tonight/tomorrow. Hope the long-range GFS is wrong...

Beyond 300 hours we are basically talking about climatological probabilities.
Last Cat 4 storm to devastate southeast Florida was 18 years ago.
Seasonal outlook for 2021 can't take into account the 19 year lull with their probability calculation..

18 years ago would be 2002. I can't recall a devastating SE FL Cat. 4 from that season

28 years ago Andrew??

[tiger_deF]

Banding is continuing to increase to the north and especially northeast of Zeta, and there are some signs of rotation within the convective mass itself. I don't know whether or not Zeta is stacked, but I definitely think it is continuing to intensify, and I think we will see some major positive structural changes over the next few hours. Has the look of a system about to take off, and once the upper level conditions cooperate (which they may not), the only limit to the amount of energy Zeta can draw from the surrounding environment is time. Considering Zeta has barely moved over the past 24 hours, and will continue to be in this environment for 2 days or more, the potential ceiling here is very high.

[Iceresistance]

Banding is continuing to increase to the north and especially northeast of Zeta, and there are some signs of rotation within the convective mass itself. I don't know whether or not Zeta is stacked, but I definitely think it is continuing to intensify, and I think we will see some major positive structural changes over the next few hours. Has the look of a system about to take off, and once the upper level conditions cooperate (which they may not), the only limit to the amount of energy Zeta can draw from the surrounding environment is time. Considering Zeta has barely moved over the past 24 hours, and will continue to be in this environment for 2 days or more, the potential ceiling here is very high.

What does 'potential ceiling' mean?

[tiger_deF]

Banding is continuing to increase to the north and especially northeast of Zeta, and there are some signs of rotation within the convective mass itself. I don't know whether or not Zeta is stacked, but I definitely think it is continuing to intensify, and I think we will see some major positive structural changes over the next few hours. Has the look of a system about to take off, and once the upper level conditions cooperate (which they may not), the only limit to the amount of energy Zeta can draw from the surrounding environment is time. Considering Zeta has barely moved over the past 24 hours, and will continue to be in this environment for 2 days or more, the potential ceiling here is very high.

What does 'potential ceiling' mean?

Maximum intensity, while I still think it will be a weak category 1 at most, if the conditions align just right the maximum intensity at least before Zeta exits into the Gulf I could see a fairly strong major.

[Iceresistance]

Banding is continuing to increase to the north and especially northeast of Zeta, and there are some signs of rotation within the convective mass itself. I don't know whether or not Zeta is stacked, but I definitely think it is continuing to intensify, and I think we will see some major positive structural changes over the next few hours. Has the look of a system about to take off, and once the upper level conditions cooperate (which they may not), the only limit to the amount of energy Zeta can draw from the surrounding environment is time. Considering Zeta has barely moved over the past 24 hours, and will continue to be in this environment for 2 days or more, the potential ceiling here is very high.

What does 'potential ceiling' mean?

Maximum intensity, while I still think it will be a weak category 1 at most, if the conditions align just right the maximum intensity at least before Zeta exits into the Gulf I could see a fairly strong major.

Unless it rapidly deepens, the SSTs are 28C, RH is over 80%, & the wind shear is lower near the core of Delta.

[Iceresistance]

The Anticyclone aloft is just about to connect with the circulation of Zeta. This is not good at all, because it is an ingredient for rapid deepening.

[Aric Dunn]

the upper air recon G-IV showing very weak ridging right now to the NE of Zeta. depending on how long it takes and how strong the riding builds in will be very important.

[aspen]

I still think there’s a slight chance Zeta will be slower than expected and not make landfall in the Yucatán later on Tuesday (maybe midday instead of early morning).

[3090]

For the first time in Zeta's existence I am finally seeing some scant evidence of northerly banding from the massive convective ball. This could potentially indicate that the center is still relocating/migrating to the South, or that upper level conditions have improved somewhat around Zeta over the past several hours.

It is ultimately going to align over the LLC that you can clearly see now on satellite. The LLC was very evident to the NNW of the large convection.

[EquusStorm]

Getting there. Just can't wrap my head around a third US Greek landfall before October's even over. That core convection is impressive if the center can consistently stack properly underneath it; would be talking about RI if the LLC had been perfectly stacked and not elongated yesterday into this morning.

[aspen]

Getting there. Just can't wrap my head around a third US Greek landfall before October's even over. That core convection is impressive if the center can consistently stack properly underneath it; would be talking about RI if the LLC had been perfectly stacked and not elongated yesterday into this morning.

Seeing convection this deep in a weak system with the opportunity to intensify is never a good sign. Extreme examples include Halong (888 mbar) and Amphan (907 mbar). It’s probably in the act of stacking as I type this, but we don’t known for several more hours until recon arrives.

[Iceresistance]

It's looking like that Zeta is already a strong tropical storm, what do you think?