2021 EPAC Season

[Kingarabian]

https://i.imgur.com/81PFcK6.png

6z GFS is strongest run yet. Track also rapidly shifting west and now in line with the ECMWF.

It’s also coming from a rather low latitude, so it’ll be within very high (29-30C) SSTs pretty early on and could have the chance for significant intensification there. However, this is a cool neutral ENSO year, and everything else has been struggling as much as in 2020, so I’d say there’s a decent chance this storm follows suit.

It's a hybrid +/- ENSO year similar to 2017. 2017 had quite a few majors. Even the crappiest of years like 2010 had a major when the track allowed it.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Fri Jul 9 2021

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

A broad area of low pressure is expected to form several hundred
miles south-southwest of the southern coast of Mexico in a few
days. Any subsequent development of this system is expected to be
gradual as it moves westward or west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

Another area of low pressure is expected to form south of the Gulf
of Tehuantepec by the middle of next week. Environmental conditions
are expected to support gradual development of this system
thereafter while it moves generally west-northwestward at 10 to 15
mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

$$
Forecaster Zelinsky

[Yellow Evan]

https://i.imgur.com/81PFcK6.png

6z GFS is strongest run yet. Track also rapidly shifting west and now in line with the ECMWF.

It’s also coming from a rather low latitude, so it’ll be within very high (29-30C) SSTs pretty early on and could have the chance for significant intensification there. However, this is a cool neutral ENSO year, and everything else has been struggling as much as in 2020, so I’d say there’s a decent chance this storm follows suit.

Given the next CCKW isn’t expected to be long lasting, I agree that a long tracked hurricane as modeled by the GFS isn’t terribly likely. Genesis could occur reasonably fast given the CCKW is fast approaching the system however.

[Yellow Evan]

12z ECMWF almost drops the westward system but still shows the eastward one.

[Kingarabian]

Still pretty good ensembles support for both systems on the 12z EPS.



If there can be some extended ridging over the EPAC, both systems have a great shot at forming and becoming hurricanes. The second system in particular can be a huge ACE maker if it can get into the CPAC and die there vs lifting NW and dying in the subtropics.

[Yellow Evan]

Nice.

[Kingarabian]

Still 10 days out but the models need to show a stronger ridge if this is going to become a decent major hurricane like Fernanda 2017 or Barbara 2019.

[Kingarabian]

The GFS is still not developing the first AOI but its pretty weird how it completely missed in the first place and the Euro/CMC doing a better job in detecting it. It's usually the opposite.

[Yellow Evan]

:uarrow: Still 10 days out but the models need to show a stronger ridge if this is going to become a decent major hurricane like Fernanda 2017 or Barbara 2019.

GFS has been trending more south at a pretty quick rate though. If that continues a potent system will appear more plausible just because PMM is so -. I’m still skeptical that stable air won’t be a problem like it is in most quantity-heavy seasons.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Fri Jul 9 2021

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

1. A broad area of low pressure is expected to form several hundred
miles south-southwest of the southern coast of Mexico by early next
week. Additional development of this system is expected to be slow
to occur while moving westward or west-northwestward at 10 to 15
mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

2. Another area of low pressure is expected to form south of the Gulf
of Tehuantepec by the middle of next week. Environmental conditions
are expected to support gradual development of this system
thereafter while moving generally west-northwestward at 10 to 15
mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

Forecaster Papin/Blake

[Yellow Evan]

18z GFS shows a long range system near the end of the run again.

[Kingarabian]

UKMET develops both systems:

[Yellow Evan]

0z GFS has a westward system although weaker.



Makes the eastward system 948 mbar.

[Yellow Evan]

0z CMC has both systems.

[Yellow Evan]

ICON also now on board.

[Yellow Evan]

000
ABPZ20 KNHC 100530
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Fri Jul 9 2021

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

An area of low pressure is expected to develop south of the Gulf of
Tehuantepec by the middle of next week. Environmental conditions are
expected to support gradual development of this system thereafter
while it moves generally west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...40 percent.

Another area of low pressure is expected to form several hundred
miles south-southwest of the southern coast of Mexico by early next
week. Development of this system should to be slow to occur while
moving westward or west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

$$
Forecaster Stewart

[Kingarabian]

00z Euro continues with the two systems:

[Yellow Evan]

000
ABPZ20 KNHC 101144
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Sat Jul 10 2021

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

An area of low pressure is expected to develop south or southeast
of the Gulf of Tehuantepec in a few days. Environmental conditions
are expected support gradual development of this system therafter
and a tropical depression could form during the middle portion of
next week. This system is expected to move generally westward or
west-northwestward at 10 to 15 mph through the end of the five day
period.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...50 percent.

Another area of low pressure is expected to form several hundred
miles southwest of the southern coast of Mexico by early next
week. Some slow development of this system will be possible while
it moves westward or west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

$$
Forecaster Zelinsky

[Yellow Evan]

6z GFS brings this to 950 mbar.

[Yellow Evan]

12z GFS is the strongest run yet and has both systems.



12z CMC has backed off and shows just one system.