2021 EPAC Season

[Yellow Evan]

0z GFS insisting on slamming this into Jalisco still.

[Yellow Evan]

000
ABPZ20 KNHC 050503
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Mon Oct 4 2021

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

An area of low pressure could form south of the southern coast of
Mexico in a few days. Gradual development of the system will be
possible beginning late this week or early this weekend while the
system moves westward to west-northwestward.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

$$
Forecaster Stewart

[Yellow Evan]

GFS develops a highly divergent environment around day 4 and has the ridge being eroded by a trough off the coast of California at around that time, which can impart mid level shear. A second trough off the coast of California then comes in and picks up this stem along with enhancing its poleward outflow.



ECMWF however keeps the ridge intact. Ridge is probably large enough to cause shear problems in that case (although I’m not 100% sure on this since I don’t have access to ECMWF products on my phone), and the surrounding environment is apparently less divergent (probably due to the GFS’s ASW bias surprise surprise). ECMWF however has been trending towards a slightly weaker ridge compared to a couple days ago. If the GFS synoptic solution verifies in the next few days, I think we could see one of those late season monster hurricanes this basin is known for in October but let’s not forget the terrible track record this model has in this basin.

[Yellow Evan]

000
ABPZ20 KNHC 051115
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Tue Oct 5 2021

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

An area of low pressure could form south of the southern coast of
Mexico late this week. Gradual development of the system will be
possible this weekend while it moves westward to west-northwestward
at 10 to 15 mph, remaining offshore the coast of southern Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

$$
Forecaster Reinhart

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Tue Oct 5 2021

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

1. An area of low pressure is forecast to form south of the southern
coast of Mexico late this week. Gradual development of the system
will be possible this weekend while it moves westward to
west-northwestward at 10 to 15 mph, remaining offshore 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]

GFS continues to trend towards a weaker ridge.



ECMWF continues to keep the ridge strong, though I don’t believe this setup as bad for deepening.



Even then, the ridge is eventually eroded by a second trough by day 6.



GFS showing a favorable trough interaction right on recurvature again.



ECMWF now calls for serious intensification by day 10 as poleward outflow is enhanced by the trough.



EPS also becoming on board slowly with a few members being GFS like.

[aspen]

https://cdn.discordapp.com/attachments/733552978572869632/895011443861258280/image0.png

GFS continues to trend towards a weaker ridge.

https://cdn.discordapp.com/attachments/733552978572869632/895013384607649792/image0.png

ECMWF continues to keep the ridge strong, though I don’t believe this setup as bad for deepening.

https://cdn.discordapp.com/attachments/733552978572869632/895017033983459368/image0.png

Even then, the ridge is eventually eroded by a second trough by day 6.

https://cdn.discordapp.com/attachments/733552978572869632/895011764180226058/image0.png

GFS showing a favorable trough interaction right on recurvature again.

https://cdn.discordapp.com/attachments/733552978572869632/895022252133847090/image0.png

ECMWF now calls for serious intensification by day 10 as poleward outflow is enhanced by the trough.

https://cdn.discordapp.com/attachments/733552978572869632/895058055648116767/epac.png

EPS also becoming on board slowly with a few members being GFS like.

This setup/track is quite ominous. Many of the strongest EPac systems — Linda, Rick, Patricia, and Willa — had this same recurve-into-Mexico track, and the fact that this would be the name that replaced Patricia isn’t helping.

Maybe it could flop like Guillermo. Maybe this setup verifies and it blows up like its predecessor (although not nearly to the same extent).

[ElectricStorm]

943mb on 18z GFS

I'm a bit skeptical since it's a -ENSO year but it needs to be watched for sure

[Astromanía]

Sinaloa, Nayarit, Jalisco and Colima should watch this closely, major cities as Mazatlan, Puerto Vallarta and Manzanillo could be in danger

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Tue Oct 5 2021

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

1. An area of low pressure is forecast to form well off the coast of
Central America and southern Mexico by the end of the week. Gradual
development of the system is possible thereafter, and a tropical
depression could form over the weekend while it moves westward to
west-northwestward.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...40 percent.

Forecaster Cangialosi

[Astromanía]

GFS into Manzanillo

[Yellow Evan]

GFS basically shows a repeat of the great Colima hurricane of 1959 at the 18z. While it shows an upper level outflow pastern that would be expected of a Category 5 hurricane, it is probably overdoing this because of it overdoes vorticity while it interacts with South America but still the apparent presence of a GOT gap event, and an unseasonably strong trough with the jet stream amplified by recurving Typhoon Mindulle is likely to aid the development of a tropical cyclone off the west coast of Mexico.

[Astromanía]

And that is the deadliest hurricane ever in EPAC, not good

[Yellow Evan]

18z EPS now have a few members showing an earlier genesis.

[Yellow Evan]

An area of low pressure is forecast to form well off the coast of
Central America and southern Mexico by the end of the week. Gradual
development of the system is possible thereafter, and a tropical
depression could form over the weekend while it moves westward to
west-northwestward.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...50 percent.

[Yellow Evan]

0z GFS is locked into the same broader setup, develops it a little slower but still has a strong hurricane into Jalisco.





ECMWF and CMC now on board.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Wed Oct 6 2021

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

1. An area of low pressure is forecast to form off the coast of Central
America and southern Mexico in a couple of days. Environmental
conditions are expected to be conducive for development thereafter,
and a tropical depression could form over the weekend while the
system moves westward to west-northwestward.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...60 percent.

Forecaster Brown

[Yellow Evan]

12z GFS slams this into Colima. Stronger this run with some overall super favorable 200 mbar pattern.

[Yellow Evan]

 https://twitter.com/icyclone/status/1445815129719795714

[Yellow Evan]

 https://twitter.com/wxmann/status/1445844985589350403