2021 EPAC Season

[Yellow Evan]

18z GFS develops the westward system pretty quickly now calling for a near hurricane in 3 days.



18z GFS develops the eastward system later on still, bringing it to 959 mbar.

[Yellow Evan]

Pretty out there as this would at least be 14 days away and not likely due to this years setup: Most recent ECMWF runs show that the 0/70 system remains weak for an extended period, moving west (possibly WSW) until it reaches the 12N-14N/126W-129W area where it begins to develop.
https://i.imgur.com/0zWVpfe.gif

Most recently, this is a spot where Hilda 2015, Hector 2018, Lane 2018, and Douglas 2020 were able to intensify while slowly lifting WNW then NW as they round the ridge. These systems all had recon so they were a Hawaii concern at one point. Of course this year's ENSO state is not on the level of 2015 and 2018 but there is some +ENSO conditions, similar to July 2020, as well as a similar SST configuration to 2020. This could be something for Hawaii to pay attention to in about 2 weeks.

This is why this isn't likely to happen. Too much shear, -PMM (unlike 2020 mind you), -PDO. Raw SST's don't really support strong hurricanes north of 15N atm.

[Kingarabian]

Pretty out there as this would at least be 14 days away and not likely due to this years setup: Most recent ECMWF runs show that the 0/70 system remains weak for an extended period, moving west (possibly WSW) until it reaches the 12N-14N/126W-129W area where it begins to develop.
https://i.imgur.com/0zWVpfe.gif

Most recently, this is a spot where Hilda 2015, Hector 2018, Lane 2018, and Douglas 2020 were able to intensify while slowly lifting WNW then NW as they round the ridge. These systems all had recon so they were a Hawaii concern at one point. Of course this year's ENSO state is not on the level of 2015 and 2018 but there is some +ENSO conditions, similar to July 2020, as well as a similar SST configuration to 2020. This could be something for Hawaii to pay attention to in about 2 weeks.

[url]https://i.imgur.com/ZDvValk.gif[url]

[url]https://i.imgur.com/UYNMeCc.png[/rl]

This is why this isn't likely to happen. Too much shear, -PMM (unlike 2020 mind you), -PDO. Raw SST's don't really support strong hurricanes north of 15N atm.

Yeah I wouldn't bet on Hawaii threats this year. If the Euro verifies though it's possible.

The Euro forecast has those strong SW's moving NW/N within time:


Something similar happened at the times of Hector, Lane, and Douglas. Here's the shear when Douglas was around:


While of course SST's don't look good at all, there's still a way in from the south, and a system would have to take a track that treads between warm and cool waters, similar to Douglas last year.
2020 SSTs:


2021: SSTs:


I'm only pointing this out because of the area where the Euro has the 0/70 developing. Off the top of my head, everytime a hurricane developed in that area (12N-14N/126W-129W), recon was sent to Hawaii.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Sun Jul 11 2021

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

1. A tropical wave located several hundred miles south of Acapulco,
Mexico is producing disorganized showers and thunderstorms.
Environmental conditions are forecast to be conducive for gradual
development, and a tropical depression could form by midweek well
offshore of the southwestern coast of Mexico while the disturbance
moves westward to west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...medium...60 percent.

2. An area of low pressure is forecast to develop south of the Gulf of
Tehuantepec around midweek and move westward or west-northwestward
at 10 to 15 mph, well offshore of the southern coast of Mexico.
Environmental conditions are expected to be favorable for
development of this system, and a tropical depression is likely to
form by late this week.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...high...70 percent.

Forecaster Reinhart/Pasch

[Kingarabian]

The 18z GFS never fails to amuse. It's not mid season 2014/2015/2016/2018 lol. How can it keep a deep system over such cool waters.


It's super long range but there's some trends from the models that shear isn't too kiiler if a system comes up from the S/SE.

[Yellow Evan]

GFS keeping hurricanes too strong over 23-25C waters is a longtime issue in this basin. Usually more a visible problem further east.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Sun Jul 11 2021

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

1. A tropical wave, accompanied by a broad area of low pressure, is
producing disorganized shower and thunderstorm activity several
hundred miles south of Acapulco, Mexico. Environmental conditions
are forecast to be conducive for gradual development, and a tropical
depression could form by midweek well offshore the southwestern
coast of Mexico while the disturbance moves westward to
west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...medium...60 percent.

2. An area of low pressure is forecast to develop south of the Gulf of
Tehuantepec around midweek and move westward or west-northwestward
at 10 to 15 mph, well offshore of the southern coast of Mexico.
Environmental conditions are expected to be favorable for
development of this system, and a tropical depression is likely to
form by late this week.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...high...70 percent.

Forecaster Stewart

[Yellow Evan]

0z ECMWF keeps the eastern system very weak now for 10 days.

[AlphaToOmega]

ZCZC MIATWOEP ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Mon Jul 12 2021

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

1. A broad area of low pressure located several hundred miles
south-southwest of Acapulco, Mexico, is producing disorganized
shower and thunderstorm activity. Environmental conditions are
expected to remain conducive for gradual development, and a
tropical depression is likely form within a few days well offshore
the southwestern coast of Mexico while the disturbance moves
westward to west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...high...70 percent.

2. An area of low pressure is forecast to develop south of the Gulf of
Tehuantepec later this week and move westward or west-northwestward
at 10 to 15 mph, well offshore of the southern coast of Mexico.
Environmental conditions are expected to be favorable for
development of this system, and a tropical depression is likely
to form by this weekend.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...high...70 percent.

Forecaster Brown

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Mon Jul 12 2021

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

1. A broad area of low pressure located several hundred miles
south of Manzanillo, Mexico, continues to produce disorganized
shower and thunderstorm activity. Environmental conditions are
expected to remain conducive for gradual development, and a
tropical depression is likely form in two to three days well
offshore the southwestern coast of Mexico while the disturbance
moves westward to west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...high...70 percent.

2. An area of low pressure is forecast to develop south of the Gulf of
Tehuantepec later this week and move westward or west-northwestward
at 10 to 15 mph, well offshore of the southern coast of Mexico.
Environmental conditions are expected to be favorable for
development of this system, and a tropical depression is likely
to form by this weekend.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...high...70 percent.

Forecaster Brown

[cycloneye]

Invest 96E is up

[aspen]

The 12z Euro and CMC are now a lot less enthusiastic about the 0/70 system compared to the 40/70 system.

[cycloneye]

The 12z Euro and CMC are now a lot less enthusiastic about the 0/70 system compared to the 40/70 system.

It develops it very late at days 9 and 10.

[Kingarabian]

Euro track for 96E and future 97E is kinda concerning. SST's will be sufficiently warm enough for a strong system to main itself and force a better than expected shear environment We'll see what happens. Hopefully the ridge remains strong.

[aspen]

The GFS has been trending weaker with slower development of 97E (the 0/70 AOI), and the 18z run reveals why: it’s modeling a broad precursor disturbance that takes time to consolidate and even attempts to split off into a second consolidating area.

[AlphaToOmega]

ZCZC MIATWOEP ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Mon Jul 12 2021

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

1. Disorganized showers and thunderstorms continue in association with
a broad area of low pressure located several hundred miles south of
Manzanillo, Mexico. Environmental conditions are expected to remain
conducive for gradual development, and a tropical depression is
likely to form later this week well offshore of the southwestern
coast of Mexico while the system moves westward to
west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...high...80 percent.

2. An area of low pressure is forecast to develop south of the Gulf of
Tehuantepec later this week and move westward at 10 to 15 mph, well
offshore of the southern coast of Mexico. Environmental conditions
are forecast to be favorable for development of this system, and a
tropical depression is likely to form by this weekend.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...high...70 percent.

Forecaster Reinhart/Pasch

[Yellow Evan]

July 21-28 seems prime time if the mean is to be believed. Might be our best shot at a major this season.

[cycloneye]

5 AM PDT:

An area of low pressure is forecast to develop south or southwest
of the Gulf of Tehuantepec late this week and move westward at 10
to 15 mph, well offshore of the southern coast of Mexico.
Environmental conditions are expected to be favorable for gradual
development, and a tropical depression is likely to form this
weekend.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...high...70 percent.

[Yellow Evan]

0z ECMWF and 6z GFS are showing vastly different trajectories with the 0/70 with the GFS trending north and moving this over cooler waters fast while the ECWF keeps this south and deepens this by day 10.

[cycloneye]

Is the first glimpse of the 0/70 one in sight below 10N?