2021 EPAC Season

[Yellow Evan]

0z GFS has a hurricane by Oaxaca but also somehow doesn’t have a displaced ULAC shearing it. So yea don’t think this is happening.

[Yellow Evan]

6z GFS.

[Yellow Evan]

GFS doing its monsoon phantom BS while the ECMWF comes in stronger.

[Yellow Evan]

18z GFS brings a hurricane almost onshore near Guerrero.



Very good upper level setup but no idea if flow will be uniform.

[Yellow Evan]

000
ABPZ20 KNHC 172313
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Sun Oct 17 2021

For the eastern North Pacific...east of 140 degrees west longitude:

A broad area of low pressure is expected to form around the middle
of the week a couple of hundred miles south of the coast of
southern Mexico. Some slow development of this system is possible
thereafter as it moves west-northwestward off the coast of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

$$
Forecaster Cangialosi

[aspen]

https://cdn.discordapp.com/attachments/733552978572869632/899428152688914512/image0.jpg

18z GFS brings a hurricane almost onshore near Guerrero.

https://cdn.discordapp.com/attachments/733552978572869632/899429404638347324/gfs_shear_epac_25.png

Very good upper level setup but no idea if flow will be uniform.

After how badly the GFS performed with Pamela and given the recent development of the La Niña, a very good UL pattern doesn’t matter. “Future Rick” will also have far less time over water than Pamela. Looks to be a late season version of Amanda ‘20.

[Ubuntwo]

After how badly the GFS performed with Pamela and given the recent development of the La Niña, a very good UL pattern doesn’t matter. “Future Rick” will also have far less time over water than Pamela. Looks to be a late season version of Amanda ‘20.

Way too early to get that specific let alone list off analogues. Very high run to run variation.

The GFS spins up the system faster than any other model, and it is the only one to depict a quick landfall. The model tends to struggle with convective feedback in monsoon troughs which can be exacerbated by tehuantepecer. Take its solution with a big load of salt.

Upper divergence is always important in tropical cyclones. La Nina is not gonna change that

[Yellow Evan]

https://cdn.discordapp.com/attachments/733552978572869632/899428152688914512/image0.jpg

18z GFS brings a hurricane almost onshore near Guerrero.

https://cdn.discordapp.com/attachments/733552978572869632/899429404638347324/gfs_shear_epac_25.png

Very good upper level setup but no idea if flow will be uniform.

After how badly the GFS performed with Pamela and given the recent development of the La Niña, a very good UL pattern doesn’t matter. “Future Rick” will also have far less time over water than Pamela. Looks to be a late season version of Amanda ‘20.

A very good UL pattern matters if there isn’t shear beneath. Otherwise, it doesn’t. With that said, I don’t really trust the modeled solutions of the GFS to verify because it’s done this sort of shenanigans before (and for some reason does so even in inactive seasons for reasons I do not know but I also think it’s somewhat sloppy analysis to fingerpoint a 12-18 month climate oscillation as to why a short range model solution would not verify) and the GFS in general has been less persistent with this than they were in the leadup to Pamela.

[Yellow Evan]

After how badly the GFS performed with Pamela and given the recent development of the La Niña, a very good UL pattern doesn’t matter. “Future Rick” will also have far less time over water than Pamela. Looks to be a late season version of Amanda ‘20.

Way too early to get that specific let alone list off analogues. Very high run to run variation.

The GFS spins up the system faster than any other model, and it is the only one to depict a quick landfall. The model tends to struggle with convective feedback in monsoon troughs which can be exacerbated by tehuantepecer. Take its solution with a big load of salt.

Upper divergence is always important in tropical cyclones. La Nina is not gonna change that

GFS is also wanting to spin up multiple tropical cyclones out of the monsoon trough which may explain the northward track but on the other hand this could lead to a faster than modeled genesis.

[Ubuntwo]

GFS is also wanting to spin up multiple tropical cyclones out of the monsoon trough which may explain the northward track but on the other hand this could lead to a faster than modeled genesis.

The GFS also has a more pronounced break in the ridge, compared to the Euro and CMC.

[Yellow Evan]

GFS is also wanting to spin up multiple tropical cyclones out of the monsoon trough which may explain the northward track but on the other hand this could lead to a faster than modeled genesis.

The GFS also has a more pronounced break in the ridge, compared to the Euro and CMC.
https://i.imgur.com/kkgC89n.png
https://i.imgur.com/6ZKfBo2.png

Of course that ridge also seems like a potential source for northwesterly mid level shear.

[aspen]

After how badly the GFS performed with Pamela and given the recent development of the La Niña, a very good UL pattern doesn’t matter. “Future Rick” will also have far less time over water than Pamela. Looks to be a late season version of Amanda ‘20.

Way too early to get that specific let alone list off analogues. Very high run to run variation.

The GFS spins up the system faster than any other model, and it is the only one to depict a quick landfall. The model tends to struggle with convective feedback in monsoon troughs which can be exacerbated by tehuantepecer. Take its solution with a big load of salt.

Upper divergence is always important in tropical cyclones. La Nina is not gonna change that

I was only listing Amanda as an analogue because of a similar genesis location just south of Guatemala/El Salvador/SE Mexico, with a landfall on the coast. There have been other storms like that too. If this disturbance tries to spin-up quickly, perhaps it could be like Max ‘17, rapidly becoming a low-end hurricane before landfall.

[Yellow Evan]

 https://twitter.com/icyclone/status/1449923215111897095

[Ubuntwo]

I was only listing Amanda as an analogue because of a similar genesis location just south of Guatemala/El Salvador/SE Mexico, with a landfall on the coast. There have been other storms like that too. If this disturbance tries to spin-up quickly, perhaps it could be like Max ‘17, rapidly becoming a low-end hurricane before landfall.

The spin up landfall on the coast is just one model solution, most take the system further west before turning north. Could also be buried w/o development. Big spread here.

[Yellow Evan]

0z GFS brings it onshore in Guerrero.



Holy ULAC.

[Yellow Evan]

427
ABPZ20 KNHC 180501
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Sun Oct 17 2021

For the eastern North Pacific...east of 140 degrees west longitude:

A broad area of low pressure is expected to form in a few days a
couple of hundred miles south of the coast of southern Mexico. Some
slow development of this system is possible thereafter as it moves
west-northwestward off the coast of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

$$
Forecaster Cangialosi

[Yellow Evan]

 https://twitter.com/andyhazelton/status/1450134878255730693

[Yellow Evan]

GFS still an outlier with this. CMC, ICON and ECMWF all weaker and offshore.

[Yellow Evan]

000
ABPZ20 KNHC 181720
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Mon Oct 18 2021

For the eastern North Pacific...east of 140 degrees west longitude:

A broad area of low pressure is expected to form in a few days a
couple of hundred miles south of the coast of southern Mexico.
Environmental conditions are expected to be conducive to support
some development thereafter, and a tropical depression could
form late this week or this weekend while the system moves
west-northwestward to northwestward near or just south of the
coast of southern Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...40 percent.

$$
Forecaster Brown

[Yellow Evan]

 https://twitter.com/icyclone/status/1450198316021657606