ATL: FRED - Post-Tropical - Discussion

[Nancy Smar]

AL, 94, 2021080806, , BEST, 0, 119N, 515W, 25, 0, DB, 0, , 0, 0, 0, 0, 0, 0, 0, 0, 0, L, 0, , 0, 0, GENESIS018, , 0, , 0, 0, 0, 0, genesis-num, 018, SPAWNINVEST, al792021 to al942021,
AL, 94, 2021080812, , BEST, 0, 119N, 529W, 25, 1009, DB, 34, NEQ, 0, 0, 0, 0, 1012, 120, 40, 0, 0, L, 0, , 0, 0, INVEST, S, 0, , 0, 0, 0, 0, genesis-num, 018,

https://ftp.nhc.noaa.gov/atcf/

[NDG]

Out of all the disturbances along the monsoonal trough this is one that all global models show at least a chance of weak develoment over the next few days.

This morning it has a fairly well defined vortex.

[aspen]

We could see a center reformation to the south where all the deepest convection is. So far, 94L has been heading due west. Maybe it might go south of the islands instead of through or north of them.

[GCANE]

Looks like its pulling moisture out of the Amazon.
Models have it amplifying TPW as it approaches the Antilles.
Could pull moisture out of the EPAC if nothing develops there then.

[GCANE]

Getting a refire on the hot tower

[Stormybajan]

Finally its 94L!! I am interested in what the hurricane models show I wonder if conditions will improve for this tiny disturbance or is dry air going affect it like it does with most systems this tiny

[Shell Mound]

 https://twitter.com/AndyHazelton/status/1424356985592586245



 https://twitter.com/NDGMETCHEF/status/1424359089455435776



 https://twitter.com/HurricaneManWx/status/1424359584785997824

[Shell Mound]

There will be a lot of anticyclonic wave-breaking over the Eastern Seaboard as 94L nears the Bahamas, and the GFS has slowly adjusted to this reality by suppressing the ULAC near Hispaniola. This would result in much stronger deep-layer VWS vectors out of the west. As a result, given that 94L is likely to be a compact system, even if it manages to develop somewhat near the Lesser Antilles, it will almost certainly be torn to shreds as it nears the Bahamas and South Florida. That ULL over Florida isn’t going to be converted into a ULAC, given 94L’s probable inability to generate a large expanse of convection that would weaken the ULL. As for the islands, 94L will be sufficiently small as to minimise its potential to generate heavy rainfall, even with its forward speed being relatively slow. So at this point I think this will become a low-end TS at most and do so briefly while near Puerto Rico. Afterward the shear, if not interaction with mountainous Hispaniola, is 99.9% certain to kill it. Note that Dorian featured an ULL to its southwest that provided ventilation as it passed east of the Bahamas (94L’s ULL will be to its northwest as it hits the Bahamas):



Link: https://youtu.be/N_OR4KzoDP8

[AutoPenalti]

There will be a lot of anticyclonic wave-breaking over the Eastern Seaboard as 94L nears the Bahamas, and the GFS has slowly adjusted to this reality by suppressing the ULAC near Hispaniola. This would result in much stronger deep-layer VWS vectors out of the west. As a result, given that 93L is likely to be a compact system, even if it manages to develop somewhat near the Lesser Antilles, it will almost certainly be torn to shreds as it nears the Bahamas and South Florida. That ULL over Florida isn’t going to be converted into a ULAC, given 93L’s probable inability to generate a large expanse of convection that would weaken the ULL. As for the islands, 93L will be sufficiently small as to minimise its potential to generate heavy rainfall, even with its forward speed being relatively slow. So at this point I think this will become a low-end TS at most and do so briefly while near Puerto Rico. Afterward the shear, if not interaction with mountainous Hispaniola, is 99.9% certain to kill it. Note that Dorian featured an ULL to its southwest that provided ventilation as it passed east of the Bahamas (93L’s ULL will be to its northwest as it hits the Bahamas):



Link: https://youtu.be/N_OR4KzoDP8

I read thinking this was about the prospects of 94L until I kept reading and mainly focused on 93L so I was slightly confused.

[Shell Mound]

There will be a lot of anticyclonic wave-breaking over the Eastern Seaboard as 94L nears the Bahamas, and the GFS has slowly adjusted to this reality by suppressing the ULAC near Hispaniola. This would result in much stronger deep-layer VWS vectors out of the west. As a result, given that 93L is likely to be a compact system, even if it manages to develop somewhat near the Lesser Antilles, it will almost certainly be torn to shreds as it nears the Bahamas and South Florida. That ULL over Florida isn’t going to be converted into a ULAC, given 93L’s probable inability to generate a large expanse of convection that would weaken the ULL. As for the islands, 93L will be sufficiently small as to minimise its potential to generate heavy rainfall, even with its forward speed being relatively slow. So at this point I think this will become a low-end TS at most and do so briefly while near Puerto Rico. Afterward the shear, if not interaction with mountainous Hispaniola, is 99.9% certain to kill it. Note that Dorian featured an ULL to its southwest that provided ventilation as it passed east of the Bahamas (93L’s ULL will be to its northwest as it hits the Bahamas):



Link: https://youtu.be/N_OR4KzoDP8

I read thinking this was about the prospects of 94L until I kept reading and mainly focused on 93L so I was slightly confused.

I apologise. I was evidently referring to 94L and have since corrected my post.

[aspen]

There will be a lot of anticyclonic wave-breaking over the Eastern Seaboard as 94L nears the Bahamas, and the GFS has slowly adjusted to this reality by suppressing the ULAC near Hispaniola. This would result in much stronger deep-layer VWS vectors out of the west. As a result, given that 94L is likely to be a compact system, even if it manages to develop somewhat near the Lesser Antilles, it will almost certainly be torn to shreds as it nears the Bahamas and South Florida. That ULL over Florida isn’t going to be converted into a ULAC, given 94L’s probable inability to generate a large expanse of convection that would weaken the ULL. As for the islands, 94L will be sufficiently small as to minimise its potential to generate heavy rainfall, even with its forward speed being relatively slow. So at this point I think this will become a low-end TS at most and do so briefly while near Puerto Rico. Afterward the shear, if not interaction with mountainous Hispaniola, is 99.9% certain to kill it. Note that Dorian featured an ULL to its southwest that provided ventilation as it passed east of the Bahamas (94L’s ULL will be to its northwest as it hits the Bahamas):



Link: https://youtu.be/N_OR4KzoDP8

Following shear forecasts that are over 5 days out is never a good idea. We’ll have to see what it becomes before the islands before we really focus on possible setups after the islands.

Speaking of Dorian, remember when it seemed like it was going to run right over the Shredder and never amount to anything significant? We need to watch out for any center jumps or track shifts that, like Dorian, could spare it from a landfall over the Greater Antilles.

[Teban54]

There will be a lot of anticyclonic wave-breaking over the Eastern Seaboard as 94L nears the Bahamas, and the GFS has slowly adjusted to this reality by suppressing the ULAC near Hispaniola. This would result in much stronger deep-layer VWS vectors out of the west. As a result, given that 94L is likely to be a compact system, even if it manages to develop somewhat near the Lesser Antilles, it will almost certainly be torn to shreds as it nears the Bahamas and South Florida. That ULL over Florida isn’t going to be converted into a ULAC, given 94L’s probable inability to generate a large expanse of convection that would weaken the ULL. As for the islands, 94L will be sufficiently small as to minimise its potential to generate heavy rainfall, even with its forward speed being relatively slow. So at this point I think this will become a low-end TS at most and do so briefly while near Puerto Rico. Afterward the shear, if not interaction with mountainous Hispaniola, is 99.9% certain to kill it. Note that Dorian featured an ULL to its southwest that provided ventilation as it passed east of the Bahamas (94L’s ULL will be to its northwest as it hits the Bahamas):



Link: https://youtu.be/N_OR4KzoDP8

Following shear forecasts that are over 5 days out is never a good idea. We’ll have to see what it becomes before the islands before we really focus on possible setups after the islands.

Speaking of Dorian, remember when it seemed like it was going to run right over the Shredder and never amount to anything significant? We need to watch out for any center jumps or track shifts that, like Dorian, could spare it from a landfall over the Greater Antilles.

And Laura.

Elsa actually almost managed to thread the needle when models were initially suggesting a Hispaniola landfall, even though it couldn't intensity for other reasons.

[NDG]

There will be a lot of anticyclonic wave-breaking over the Eastern Seaboard as 94L nears the Bahamas, and the GFS has slowly adjusted to this reality by suppressing the ULAC near Hispaniola. This would result in much stronger deep-layer VWS vectors out of the west. As a result, given that 94L is likely to be a compact system, even if it manages to develop somewhat near the Lesser Antilles, it will almost certainly be torn to shreds as it nears the Bahamas and South Florida. That ULL over Florida isn’t going to be converted into a ULAC, given 94L’s probable inability to generate a large expanse of convection that would weaken the ULL. As for the islands, 94L will be sufficiently small as to minimise its potential to generate heavy rainfall, even with its forward speed being relatively slow. So at this point I think this will become a low-end TS at most and do so briefly while near Puerto Rico. Afterward the shear, if not interaction with mountainous Hispaniola, is 99.9% certain to kill it. Note that Dorian featured an ULL to its southwest that provided ventilation as it passed east of the Bahamas (94L’s ULL will be to its northwest as it hits the Bahamas):

We will have to see if the GFS will be correct with the position of that ULL over FL.
The Euro forecasts it to move out of the way towards the GOM.

[SFLcane]

[gatorcane]

There will be a lot of anticyclonic wave-breaking over the Eastern Seaboard as 94L nears the Bahamas, and the GFS has slowly adjusted to this reality by suppressing the ULAC near Hispaniola. This would result in much stronger deep-layer VWS vectors out of the west. As a result, given that 93L is likely to be a compact system, even if it manages to develop somewhat near the Lesser Antilles, it will almost certainly be torn to shreds as it nears the Bahamas and South Florida. That ULL over Florida isn’t going to be converted into a ULAC, given 93L’s probable inability to generate a large expanse of convection that would weaken the ULL. As for the islands, 93L will be sufficiently small as to minimise its potential to generate heavy rainfall, even with its forward speed being relatively slow. So at this point I think this will become a low-end TS at most and do so briefly while near Puerto Rico. Afterward the shear, if not interaction with mountainous Hispaniola, is 99.9% certain to kill it. Note that Dorian featured an ULL to its southwest that provided ventilation as it passed east of the Bahamas (93L’s ULL will be to its northwest as it hits the Bahamas):



Link: https://youtu.be/N_OR4KzoDP8

I read thinking this was about the prospects of 94L until I kept reading and mainly focused on 93L so I was slightly confused.

I apologise. I was evidently referring to 94L and have since corrected my post.

Watching that loop of Dorian, amazing how Dorian just literally stopped right before Florida and moved north, even when a lot of models showed it hitting Florida or even crossing over into the GOM within 5 days. The saving grace trough showed up literally at the last minute and saved what would have been billions in damages to the state and perhaps the costliest hurricane to ever impact Florida.

[GCANE]

About 4 days out at 250mb.
X is approx location of max 700mb vort.
Under a weak anticyclone with a good poleward outflow channel.
Will need to cut thru the ULL over FL.
Could easily do that with strong towers and afternoon popups over FL.
Models totally fail on forecasting mesoscale dynamics.

[Stormybajan]

https://i.postimg.cc/QdGQTyyH/AAD422-BF-94-A1-4-CB9-BD36-134-BFC26433-E.gif

If 94L really wants to get going imo it needs to relocate the center slightly south into that ball of convection away from dry air

[Shell Mound]

There will be a lot of anticyclonic wave-breaking over the Eastern Seaboard as 94L nears the Bahamas, and the GFS has slowly adjusted to this reality by suppressing the ULAC near Hispaniola. This would result in much stronger deep-layer VWS vectors out of the west. As a result, given that 94L is likely to be a compact system, even if it manages to develop somewhat near the Lesser Antilles, it will almost certainly be torn to shreds as it nears the Bahamas and South Florida. That ULL over Florida isn’t going to be converted into a ULAC, given 94L’s probable inability to generate a large expanse of convection that would weaken the ULL. As for the islands, 94L will be sufficiently small as to minimise its potential to generate heavy rainfall, even with its forward speed being relatively slow. So at this point I think this will become a low-end TS at most and do so briefly while near Puerto Rico. Afterward the shear, if not interaction with mountainous Hispaniola, is 99.9% certain to kill it. Note that Dorian featured an ULL to its southwest that provided ventilation as it passed east of the Bahamas (94L’s ULL will be to its northwest as it hits the Bahamas):



Link: https://youtu.be/N_OR4KzoDP8

Following shear forecasts that are over 5 days out is never a good idea.

This is not a long-range forecast. I am only alluding to factors that are going to be present within three days. The GFS shows a robust ULL over and near Florida in just three days. I don’t see how this forecast is going to be substantially incorrect, as the ECMWF shows a similarly unfavourable setup, at least for a brief(-er) period, though per the latter the ULL vacates the premises by 00:00 UTC on 14 August. Given that 93L is going to be a compact system, it will struggle to survive such a high level of VWS. Furthermore, its position relative to the ULL will be critical at all stages, starting in three days. It will also need to strengthen significantly within the next forty-eight to seventy-two hours in order to place itself in a better position vis-à-vis the ULL.

[GCANE]

Hot tower firing seems to be switching into constant mode.
Let's see if NHC posts recon tasking today.

[NDG]

Not quiet detached from the monsoonal trough. The northern vorticity is the one that will probably take over.