ATL: DELTA - Post-Tropical - Discussion

[p1nheadlarry]

I wish no one would have to deal with this but I have to say I'm encouraged that Michael affected areas are not likely to be impacted much, if at all by Delta if the current trends continue...

Hopefully. I'm not saying you did, but I personally wouldn't slam the door on Panama City. While the current cone runs to Walton?Bay County on its eastern extreme, cone of uncertainty could have an eastern periphery another 100-150 miles east (or west) in the next 3-4 days. Models are pretty tightly clustered, but we all know the later in the season it gets, the more likely Gulf systems would be on the easterly side of a potential threat area (this is NOT 100% ). Just the same, there looks to be a push from the east in the Atlantic almost guaranteeing that there's some point along the Panhandle that would be too far east for it to get to. Look at Water Vapor:

Water Vapor
https://cdn.star.nesdis.noaa.gov//GOES1 ... 00x540.gif


Now run (press the play button) the GFS @ 500mb. This is easy to match up with the Water Vapor as you can see the ridging across Florida from the W Atlantic not relenting. This ridging (looks like a mid-upper level finger ridge) is clearly the feature that will direct Delta NW for a while before rounding the western periphery. BUT, down the line, the GFS has sort of backed off on the approaching long wave that was set to follow Delta by a couple of days. Now a small buckle (a really shortwave) picks it up and directs it out. The upper trough/longwave now lifts up and out after Delta does, so now there really isn't a large scale continental trough that can push it up farther east more quickly.

GFS @ 500mb
https://www.tropicaltidbits.com/analysi ... 00506&fh=6

If things stay as they are, we can narrow the expected landfall area almost to Morgan City to Navarre Beach and should be able to further hone it in as the week goes on. But again for now, there's no way Panama City should be considered out of the woods IMHO.

It's also important to note that you don't need to be inside the cone to have significant impacts, if the storm comes further east and you're on the east side of it, you're likely to be impacted in some fashion, even if you're not in the cone.

What I worry about with the areas affected by Sally. Still would produce onshore flow if the COC passes further west than Gulf Shores.

[AJC3]

Hey, just catching back up on this thread/reply. You're right on pointing out how the first two points have been close to nullified thanks to Delta's organizational trends and Gamma's lack of well... much of anything, really. However, wouldn't Gamma still impart a mild amount of shear at the low to mid-levels? This probably would not have much of an impact on Delta (if it organizes a strong inner core like it appears to be doing so), but it might be worth seeing if it serves as a bit of an inhibitor on Delta's potential as it approaches Cuba.

In terms of Gamma pivoting Delta westward, such a scenario seems to be getting further and further unlikely. Although, it must then be wondered why this morning's runs have shifted westward regardless...

There may not be much of anything left of the system at 500mb in a few days, especially if it fails to regenerate any convection (think VHTs) near the center. I suspect its entire 3D vortical structure will continue to degrade. Watch for this trend in the 500MB height/vort/wind init panels, which serve as a decent proxy for analyses.

[GCANE]

Looking at CIMSS, the PV Streamer appears to have gotten over the CoC.
These things can be very deceptive.
What appears to be a warm-core feature may in fact be the PVS.
It would put a lid on getting the vorts stacked.
A lot of convection firing around this though.
Usually takes about 12 hrs or so for it to shake out.
Once the PVS goes, that trof to the east would likely setup a good poleward outflow channel.

Might be a little over my head, but aren't upper level +PV anomalies cold? Wind shear from PVS is produced by vertical gradient where winds increase with height which in thermal wind balance means cold.

They are vorts at the upper end of the troposphere.
They push cold / dry air down to the mid and lower levels.

[GCANE]

Lightning firing on the new hot tower now.
Hours are numbered for the PVS.

[aspen]

Delta appears to be having its first little hiccup, because that warm spot seems to be a dry slot. It should be able to mix that out.

[3090]

I wish no one would have to deal with this but I have to say I'm encouraged that Michael affected areas are not likely to be impacted much, if at all by Delta if the current trends continue...

Hopefully. I'm not saying you did, but I personally wouldn't slam the door on Panama City. While the current cone runs to Walton?Bay County on its eastern extreme, cone of uncertainty could have an eastern periphery another 100-150 miles east (or west) in the next 3-4 days. Models are pretty tightly clustered, but we all know the later in the season it gets, the more likely Gulf systems would be on the easterly side of a potential threat area (this is NOT 100% ). Just the same, there looks to be a push from the east in the Atlantic almost guaranteeing that there's some point along the Panhandle that would be too far east for it to get to. Look at Water Vapor:

Water Vapor
https://cdn.star.nesdis.noaa.gov//GOES1 ... 00x540.gif


Now run (press the play button) the GFS @ 500mb. This is easy to match up with the Water Vapor as you can see the ridging across Florida from the W Atlantic not relenting. This ridging (looks like a mid-upper level finger ridge) is clearly the feature that will direct Delta NW for a while before rounding the western periphery. BUT, down the line, the GFS has sort of backed off on the approaching long wave that was set to follow Delta by a couple of days. Now a small buckle (a really shortwave) picks it up and directs it out. The upper trough/longwave now lifts up and out after Delta does, so now there really isn't a large scale continental trough that can push it up farther east more quickly.

GFS @ 500mb
https://www.tropicaltidbits.com/analysi ... 00506&fh=6

If things stay as they are, we can narrow the expected landfall area almost to Morgan City to Navarre Beach and should be able to further hone it in as the week goes on. But again for now, there's no way Panama City should be considered out of the woods IMHO.

So you are going against all of the grain, from the Big Bend of Texas, to the Destin area?

[GCANE]

Usually don't see such a deep red for OHC, even in the west Carib
Also figuring the PVS will be gone in less than 18 hrs.

[aspen]

Usually don't see such a deep red for OHC, even in the west Carib
Also figuring the PVS will be gone in less than 18 hrs.


https://i.imgur.com/WZctFYG.gif

Here’s the 12z map:

[GCANE]

The way IR is starting to look, I have a feeling this could start out as a pinhole.
Recon will tell us for sure.

[ElectricStorm]

If I remember correctly, yesterday's HWRF run that showed the pinhole really didn't get delta going until tomorrow, so today may not be that big of a day for Delta concerning RI potential. However, if Delta gets going quicker than expected this afternoon and tonight, it could really explode tomorrow and Wednesday. Just something to watch for.

[aspen]

If I remember correctly, yesterday's HWRF run that showed the pinhole really didn't get delta going until tomorrow, so today may not be that big of a day for Delta concerning RI potential. However, if Delta gets going quicker than expected this afternoon and tonight, it could really explode tomorrow and Wednesday. Just something to watch for.

Delta is looking similar to the simulated IR at 18z today from yesterday’s 12z run, and that run also had a bombing out pinhole major on Tuesday.

[DestinHurricane]

I wish no one would have to deal with this but I have to say I'm encouraged that Michael affected areas are not likely to be impacted much, if at all by Delta if the current trends continue...

Hopefully. I'm not saying you did, but I personally wouldn't slam the door on Panama City. While the current cone runs to Walton?Bay County on its eastern extreme, cone of uncertainty could have an eastern periphery another 100-150 miles east (or west) in the next 3-4 days. Models are pretty tightly clustered, but we all know the later in the season it gets, the more likely Gulf systems would be on the easterly side of a potential threat area (this is NOT 100% ). Just the same, there looks to be a push from the east in the Atlantic almost guaranteeing that there's some point along the Panhandle that would be too far east for it to get to. Look at Water Vapor:

Water Vapor
https://cdn.star.nesdis.noaa.gov//GOES1 ... 00x540.gif


Now run (press the play button) the GFS @ 500mb. This is easy to match up with the Water Vapor as you can see the ridging across Florida from the W Atlantic not relenting. This ridging (looks like a mid-upper level finger ridge) is clearly the feature that will direct Delta NW for a while before rounding the western periphery. BUT, down the line, the GFS has sort of backed off on the approaching long wave that was set to follow Delta by a couple of days. Now a small buckle (a really shortwave) picks it up and directs it out. The upper trough/longwave now lifts up and out after Delta does, so now there really isn't a large scale continental trough that can push it up farther east more quickly.

GFS @ 500mb
https://www.tropicaltidbits.com/analysi ... 00506&fh=6

If things stay as they are, we can narrow the expected landfall area almost to Morgan City to Navarre Beach and should be able to further hone it in as the week goes on. But again for now, there's no way Panama City should be considered out of the woods IMHO.

So you are going against all of the grain, from the Big Bend of Texas, to the Destin area?

What do you mean? Morgan city to Destin seems reasonable IMO.

[gfsperpendicular]

This might be a long thread

100% will be one of the most longest threads of 2020 but will it beat Laura's main discussion thread that had 392 pages? Isaias had 284 pages on the main discussion thread.

Fun question but I will say no as it appears the SFL and Texas threats have decreased and Laura's long time as an invest will give it a boost.

[shansgonefishin]

Here’s a link to the Cayman Islands Radar in case anyone’s interested when it rolls through, sunny here today here in Grand Cayman.... I guess not for long!

http://www.weather.gov.ky/portal/page/portal/nwshome/forecasthome/radar

[MGC]

Lets hope all that mid and upper level dry air get entrained into Delta's circulation in the coming days and keep a lid on things.....Doubt the OHC in the northern gulf can support a major but the hurricane has plenty of super heated water to transverse the next couple of days......MGC

[cheezyWXguy]

So delta seems to have a cloud filled eye now. Huh.

[Blinhart]

Hey, just catching back up on this thread/reply. You're right on pointing out how the first two points have been close to nullified thanks to Delta's organizational trends and Gamma's lack of well... much of anything, really. However, wouldn't Gamma still impart a mild amount of shear at the low to mid-levels? This probably would not have much of an impact on Delta (if it organizes a strong inner core like it appears to be doing so), but it might be worth seeing if it serves as a bit of an inhibitor on Delta's potential as it approaches Cuba.

In terms of Gamma pivoting Delta westward, such a scenario seems to be getting further and further unlikely. Although, it must then be wondered why this morning's runs have shifted westward regardless...

There may not be much of anything left of the system at 500mb in a few days, especially if it fails to regenerate any convection (think VHTs) near the center. I suspect its entire 3D vortical structure will continue to degrade. Watch for this trend in the 500MB height/vort/wind init panels, which serve as a decent proxy for analyses.

I think you might be in the wrong thread, this is for Delta not Gamma.

[aspen]

When is recon expected to take off?

[Steve]

I wish no one would have to deal with this but I have to say I'm encouraged that Michael affected areas are not likely to be impacted much, if at all by Delta if the current trends continue...

Hopefully. I'm not saying you did, but I personally wouldn't slam the door on Panama City. While the current cone runs to Walton?Bay County on its eastern extreme, cone of uncertainty could have an eastern periphery another 100-150 miles east (or west) in the next 3-4 days. Models are pretty tightly clustered, but we all know the later in the season it gets, the more likely Gulf systems would be on the easterly side of a potential threat area (this is NOT 100% ). Just the same, there looks to be a push from the east in the Atlantic almost guaranteeing that there's some point along the Panhandle that would be too far east for it to get to. Look at Water Vapor:

Water Vapor
https://cdn.star.nesdis.noaa.gov//GOES1 ... 00x540.gif


Now run (press the play button) the GFS @ 500mb. This is easy to match up with the Water Vapor as you can see the ridging across Florida from the W Atlantic not relenting. This ridging (looks like a mid-upper level finger ridge) is clearly the feature that will direct Delta NW for a while before rounding the western periphery. BUT, down the line, the GFS has sort of backed off on the approaching long wave that was set to follow Delta by a couple of days. Now a small buckle (a really shortwave) picks it up and directs it out. The upper trough/longwave now lifts up and out after Delta does, so now there really isn't a large scale continental trough that can push it up farther east more quickly.

GFS @ 500mb
https://www.tropicaltidbits.com/analysi ... 00506&fh=6

If things stay as they are, we can narrow the expected landfall area almost to Morgan City to Navarre Beach and should be able to further hone it in as the week goes on. But again for now, there's no way Panama City should be considered out of the woods IMHO.

So you are going against all of the grain, from the Big Bend of Texas, to the Destin area?

No. I think it's going to landfall on the northern Gulf Coast. For now, I'd have to go with Abbeville to Destin. But with around 4 1/2 days out, you'd like to be a little closer than 400 miles, right? I know I would. This has been a tough year to figure out tracks for Gulf storm landfall points besides of Cristobal. Gun to the head guess right now would be Grand Isle to Pensacola Beach somewhere (or if you had to magnify it, Grand Isle to Mobile County). However, we won't really be able to tell until we see how the ridge across peninsular Florida evolves. If it's weaker or has a different configuration than I showed in the GFS 12z, it's going to behave differently. I personally don't see it hitting Texas at this point, and I don't think it's going to hit the FL Peninsula. That's basically where I'm at with a landfall east of Laura's.

[psyclone]

Hey, just catching back up on this thread/reply. You're right on pointing out how the first two points have been close to nullified thanks to Delta's organizational trends and Gamma's lack of well... much of anything, really. However, wouldn't Gamma still impart a mild amount of shear at the low to mid-levels? This probably would not have much of an impact on Delta (if it organizes a strong inner core like it appears to be doing so), but it might be worth seeing if it serves as a bit of an inhibitor on Delta's potential as it approaches Cuba.

In terms of Gamma pivoting Delta westward, such a scenario seems to be getting further and further unlikely. Although, it must then be wondered why this morning's runs have shifted westward regardless...

There may not be much of anything left of the system at 500mb in a few days, especially if it fails to regenerate any convection (think VHTs) near the center. I suspect its entire 3D vortical structure will continue to degrade. Watch for this trend in the 500MB height/vort/wind init panels, which serve as a decent proxy for analyses.

I think you might be in the wrong thread, this is for Delta not Gamma.

follow the thread back. he is very much in the correct sandbox although it's been easy to get confused this year..