ATL: JOSEPHINE - Remnants - Discussion

[tolakram]

floater: https://rammb-slider.cira.colostate.edu/?sat=goes-16&z=1&im=28&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=0&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=mesoscale_02&p%5B0%5D=band_02&x=1026.934326171875&y=1058.9660949707031

[Aric Dunn]

Center is still on the eastern edge of the convection. Looks barely more than a strong tropical wave. Struggling with wind shear. Careful using those multispectral winds, as they may be looking at rotation aloft. Could become a TS later today or tomorrow but it still doesn't have much future. Probably opening up into a wave as it approaches the NE Caribbean Saturday night.

http://wxman57.com/images/95Lb.JPG

that is not a muli spectral image .. that is a Scat pass..

secondly, the center is not where you have it.

[GCANE]

Starting to get a better picture of the current condition of the thermal profile of the core.
As expected, the warm core is slightly to the west of the center of circulation.
Air parcel trajectory is shown in pink.
A normal cold pocket is below the warm core which creates the updraft.
However, there is an unusually cold pocket above the warm core creating a greater than normal updraft as the air parcels swing by the warm core.
This is allowing the vortical hot towers to fire off at a pace that is above normal.
Any tower that fires close to the CoC will add latent heating into the core and cause an acceleration in strengthening.
I can't expressive enough that GFS is totally missing the boat on how this is modeling SAL / dry air involvement.
This TC is IMHO more prone to strengthening than currently being forecasted.

[Aric Dunn]

Scat Sat( though not the most reliable scat) just scraped along the western edge of the curved band that is developing..

shows a few 35kt barbs..


waiting for a good pass of ASCAT and we may very well have Josephine soon.

[Dean4Storms]

Circulation at least just above the surface looks elongated once again from SW to NE looking at the clouds.

[GCANE]

This thing is totally obliterating the dry air around it.
Visible showing an unusual infeed from the NE. Not sure where that is coming from.
Also, an unusually high infeed of TPW air in the 500 to 700 mb level.

[TallyTracker]

This thing is totally obliterating the dry air around it.
Visible showing an unusual infeed from the NE. Not sure where that is coming from.
Also, an unusually high infeed of TPW air in the 500 to 700 mb level.


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

https://i.imgur.com/Fd2dcsi.png

https://i.imgur.com/lR9X0Hv.png

It appears to me that the easterly shear may be partially responsible for the dry air being pushed away. It’s exposing the center some, but may be giving the system a chance.

[Aric Dunn]

This thing is totally obliterating the dry air around it.
Visible showing an unusual infeed from the NE. Not sure where that is coming from.
Also, an unusually high infeed of TPW air in the 500 to 700 mb level.


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

https://i.imgur.com/Fd2dcsi.png

https://i.imgur.com/lR9X0Hv.png

It appears to me that the easterly shear may be partially responsible for the dry air being pushed away. It’s exposing the center some, but may be giving the system a chance.

Yeppers. it has been forcing moisture west ahead of it into the mid and upper levels. funny how there is always a fine balance.. it both never would have formed and formed because of the easterly shear

[curtadams]

Starting to get a better picture of the current condition of the thermal profile of the core.
As expected, the warm core is slightly to the west of the center of circulation.
Air parcel trajectory is shown in pink.
A normal cold pocket is below the warm core which creates the updraft.
However, there is an unusually cold pocket above the warm core creating a greater than normal updraft as the air parcels swing by the warm core.
This is allowing the vortical hot towers to fire off at a pace that is above normal.
Any tower that fires close to the CoC will add latent heating into the core and cause an acceleration in strengthening.
I can't expressive enough that GFS is totally missing the boat on how this is modeling SAL / dry air involvement.
This TC is IMHO more prone to strengthening than currently being forecasted.

https://i.imgur.com/XZcDK3B.png

That doesn't look like much of a warm core. I was going to say the spirally curved convection looks like a subtropical storm.

[Visioen]

Based on the NHC discussion it seems to me there will be at least a small window to allow for some quick strenghtening before westerly shear kicks in:

...to give way to more conducive environmental conditions by 24 h when the cyclone will begin to move underneath the center of a synoptic-scale upper-level anticyclone. This will result in the shear decreasing to near zero, along with a pronounced improvement in the upper-level outflow pattern.

TC underneatch the upper anticyclone with excellent outflow:

[Visioen]

Lol new NHC discussion is out, still allows for that scenario though:

Tropical Depression Eleven Discussion Number 4
NWS National Hurricane Center Miami FL AL112020
1100 AM AST Wed Aug 12 2020

Satellite imagery indicates that the depression is a little better
organized than 24 h ago, with a ragged central convective feature
and a curved convective band in the northwestern semicircle.
However, recent scatterometer data show this has not yet resulted
in strengthening, with 25-30 kt winds occuring to the north of the
center. Based on the scatterometer, the initial intensity remains
30 kt.

The initial motion remains a little north of due west, or
280/13 kt. There is little change to the forecast philosophy or
the forecast track since the last advisory. A westward motion is
expected to continue through tonight due to easterly flow on the
south side of a strong subtropical ridge situated to the north of
the cyclone. After that, the global models forecast a slight
weakness to develop within the ridge, allowing the cyclone to turn
west-northwestward, with that motion continuing through the end of
the forecast period. The new NHC forecast is just to the left of
the various consensus models.

The southeasterly shear that has so far prevented intensification
should diminish in the next 12 h or so, which should allow the
cyclone to become a tropical storm. The system should then remain
in light to moderate shear through about 48 h, and the intensity
forecast calls for a peak intensity of 50 kt during that time.
Later in the forecast period, moderate to strong southwesterly
shear should develop over the cyclone due to an upper-level trough
over the southwestern Atlantic. This shear should cause the system
to weaken, and several of the global models forecast it to
degenerate to a tropical wave before 120 h. The new intensity
forecast will not call for that quick of a demise, but will show
weakening due to the shear after 72 h. The new forecast, which has
only minor changes from the previous forecast, is near the upper
edge of the intensity guidance.

[GCANE]

Based on the NHC discussion it seems to me there will be at least a small window to allow for some quick strenghtening before westerly shear kicks in:

...to give way to more conducive environmental conditions by 24 h when the cyclone will begin to move underneath the center of a synoptic-scale upper-level anticyclone. This will result in the shear decreasing to near zero, along with a pronounced improvement in the upper-level outflow pattern.

TC underneatch the upper anticyclone with excellent outflow:

https://i.imgur.com/a5ug3Ug.png

The "Synoptic-Scale Upper-Level Anticyclone" is what I have been referring to as the Anticyclone Wave Break (AWB)
TD11 is already getting close to it and the effects can be seen.
Once shear relaxes substantially, a Convective Anticyclone will likely develop and phase with the AWB.
This effect could setup some rapid strengthening.
Bear in mind also, the models are completely missing the effects of dry air and SAL
They currently show heavy SAL involvement while satellite imagery plainly indicates this is not the case.
The best bet IMHO is for recon to sample as soon as possible and to run high-level GIV.

[aspen]

Based on the NHC discussion it seems to me there will be at least a small window to allow for some quick strenghtening before westerly shear kicks in:

...to give way to more conducive environmental conditions by 24 h when the cyclone will begin to move underneath the center of a synoptic-scale upper-level anticyclone. This will result in the shear decreasing to near zero, along with a pronounced improvement in the upper-level outflow pattern.

TC underneatch the upper anticyclone with excellent outflow:

https://i.imgur.com/a5ug3Ug.png

The "Synoptic-Scale Upper-Level Anticyclone" is what I have been referring to as the Anticyclone Wave Break (AWB)
TD11 is already getting close to it and the effects can be seen.
Once shear relaxes substantially, a Convective Anticyclone will likely develop and phase with the AWB.
This effect could setup some rapid strengthening.
Bear in mind also, the models are completely missing the effects of dry air and SAL
They currently show heavy SAL involvement while satellite imagery plainly indicates this is not the case.
The best bet IMHO is for recon to sample as soon as possible and to run high-level GIV.

So if this verifies, could there be a chance for Josephine to become a minor hurricane before shear reaches unfavorable levels?

[GCANE]

Based on the NHC discussion it seems to me there will be at least a small window to allow for some quick strenghtening before westerly shear kicks in:

...to give way to more conducive environmental conditions by 24 h when the cyclone will begin to move underneath the center of a synoptic-scale upper-level anticyclone. This will result in the shear decreasing to near zero, along with a pronounced improvement in the upper-level outflow pattern.

TC underneatch the upper anticyclone with excellent outflow:

https://i.imgur.com/a5ug3Ug.png

The "Synoptic-Scale Upper-Level Anticyclone" is what I have been referring to as the Anticyclone Wave Break (AWB)
TD11 is already getting close to it and the effects can be seen.
Once shear relaxes substantially, a Convective Anticyclone will likely develop and phase with the AWB.
This effect could setup some rapid strengthening.
Bear in mind also, the models are completely missing the effects of dry air and SAL
They currently show heavy SAL involvement while satellite imagery plainly indicates this is not the case.
The best bet IMHO is for recon to sample as soon as possible and to run high-level GIV.

So if this verifies, could there be a chance for Josephine to become a minor hurricane before shear reaches unfavorable levels?

If a system develops along the east coast over the weekend, conditions may actually not reach unfavorable levels.

[wxman57]

Diminishing convection over the past few hours has allowed a small vortex to peek through. It appears to be rotating southwestward on the western side of a broader low pressure area. We see many such vortices near the crests of strong waves through the season. Generally, they're ignored. Still looks like it is weakening as it passes NE of the Caribbean this weekend. A hurricane seems quite unlikely.

[Aric Dunn]

The "Synoptic-Scale Upper-Level Anticyclone" is what I have been referring to as the Anticyclone Wave Break (AWB)
TD11 is already getting close to it and the effects can be seen.
Once shear relaxes substantially, a Convective Anticyclone will likely develop and phase with the AWB.
This effect could setup some rapid strengthening.
Bear in mind also, the models are completely missing the effects of dry air and SAL
They currently show heavy SAL involvement while satellite imagery plainly indicates this is not the case.
The best bet IMHO is for recon to sample as soon as possible and to run high-level GIV.

So if this verifies, could there be a chance for Josephine to become a minor hurricane before shear reaches unfavorable levels?

If a system develops along the east coast over the weekend, conditions may actually not reach unfavorable levels.

Like I mentioned before.. a stronger more vertically stacked system may have a tendency to move farther west. as the 500 MB and up ridging is stronger and models show it more intact.

If the globals stop showing it staying weak for the next 48 hours and it does get up to what the NHC has it or a minimal hurricane then expect the models to shift south and west.

[Nuno]

Diminishing convection over the past few hours has allowed a small vortex to peek through. It appears to be rotating southwestward on the western side of a broader low pressure area. We see many such vortices near the crests of strong waves through the season. Generally, they're ignored. Still looks like it is weakening as it passes NE of the Caribbean this weekend. A hurricane seems quite unlikely.

http://wxman57.com/images/96Lc.JPG

NHC forecasts lessening shear over a short enough time to allow for moderate strengthening, you don't think this has a shot at attaining moderate/strong TS strength?

[Aric Dunn]

Shear is still present but decreasing compared to yesterday. nice large curved band on the west side. convection should again burst over the center in the coming hours.

[GCANE]

Twin towers poppin up.
One just north of the swirl.
The other a little farther away to the NE.

[Aric Dunn]

Twin towers poppin up.
One just north of the swirl.
The other a little farther away to the NE.

was just going to mention.. likely a big burst of convection coming.. Towers to the south as well.

closer to the center cloud deck is thickening. something is coming..