2021 EPAC Season

[Kingarabian]

12z CMC had that 10 day system developing earlier and making landfall. Also shows another system in 10 days in the east EPAC:

[Kingarabian]

The Atlantic doesn't get active until late July/mid August. So we could see quite a bit of AEW's reach the EPAC during July and August, potentially creating a train of TC's.

[Yellow Evan]

18z GFS now bringing this onshore Michoacán.

[cycloneye]

94E going up shortly.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Wed Jun 16 2021

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

1. A surface trough of low pressure is producing a large area of
disorganized showers and thunderstorms that extends several hundred
miles south of the coast of southern Mexico. Environmental
conditions appear conducive for development of this system, and a
tropical depression is likely to form late this week while moving
west-northwestward or northwestward at 5 to 10 mph, near the coast
of southwestern Mexico. Regardless of development, heavy rains are
likely over coastal sections of the Mexican states of Oaxaca,
Guerrero, Michoacan, Colima, and Jalisco during the next few days,
which could cause life-threatening flash floods and mud slides.
Interests in these areas should monitor the progress of this system
through the weekend.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...high...80 percent.

Forecaster Reinhart/Beven

[ElectricStorm]

94E going up shortly.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Wed Jun 16 2021

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

1. A surface trough of low pressure is producing a large area of
disorganized showers and thunderstorms that extends several hundred
miles south of the coast of southern Mexico. Environmental
conditions appear conducive for development of this system, and a
tropical depression is likely to form late this week while moving
west-northwestward or northwestward at 5 to 10 mph, near the coast
of southwestern Mexico. Regardless of development, heavy rains are
likely over coastal sections of the Mexican states of Oaxaca,
Guerrero, Michoacan, Colima, and Jalisco during the next few days,
which could cause life-threatening flash floods and mud slides.
Interests in these areas should monitor the progress of this system
through the weekend.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...high...80 percent.

Forecaster Reinhart/Beven

Anyone know why they like to take so long to tag invests in the EPAC? Seems like they always wait so much longer than they do for Atlantic systems

[Kingarabian]

Anyone know why they like to take so long to tag invests in the EPAC? Seems like they always wait so much longer than they do for Atlantic systems

No clue. They are being pretty conservative with this system. Odds should be higher than 60/80.

[aspen]

Anyone know why they like to take so long to tag invests in the EPAC? Seems like they always wait so much longer than they do for Atlantic systems

No clue. They are being pretty conservative with this system. Odds should be higher than 60/80.

I think they’re being conservative because of how close it’ll be to the coast, meaning it can possibly run into land before even becoming a classifiable TC.

[Yellow Evan]

Anyone know why they like to take so long to tag invests in the EPAC? Seems like they always wait so much longer than they do for Atlantic systems

No clue. They are being pretty conservative with this system. Odds should be higher than 60/80.

I think they’re being conservative because of how close it’ll be to the coast, meaning it can possibly run into land before even becoming a classifiable TC.

They're being conservative likely because the ECMWF isn't that aggressive, and the GFS has a terrible track record of tropical cyclone genesis.

[Kingarabian]

No clue. They are being pretty conservative with this system. Odds should be higher than 60/80.

I think they’re being conservative because of how close it’ll be to the coast, meaning it can possibly run into land before even becoming a classifiable TC.

They're being conservative likely because the ECMWF isn't that aggressive, and the GFS has a terrible track record of tropical cyclone genesis.

ECMWF's deterministic model can't initialize anything properly. So if a system will form and landfall in about 72 hours total, it won't look aggressive since per 24 hour timeframe it will do 1009mb, 1007mb, then 1005mb. However the EPS which can resolve this type of genesis better, is very bullish, consistently showing a >90% chance for a TD and now a 75% chance of a TS in 72 hours.

18z deterministic/operational Euro now even shows a 45-50kt landfall in relation to this 60/80 system @ 78 hours.

I imagine it would be better to get the HWRF/HMON runs and see what they think since landfall is less than 3 days out.

[Yellow Evan]

Tbf we have HWRF runs and both HMON/HWRF have an eastward bias in this area of the world so their value is more limited.

But we do have the HWRF parent dominant of 92L.

[Kingarabian]

00z GFS:


00z UKMET:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 42 HOURS
FORECAST POSITION AT T+ 42 : 15.2N 102.2W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 19.06.2021 48 15.6N 103.1W 1003 30
1200UTC 19.06.2021 60 16.6N 104.5W 1002 32
0000UTC 20.06.2021 72 18.0N 105.2W 998 42
1200UTC 20.06.2021 84 20.5N 105.7W 993 50
0000UTC 21.06.2021 96 CEASED TRACKING

00z CMC down to 999mb, so its a legit TS.

[Kingarabian]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Wed Jun 16 2021

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

1. A surface trough of low pressure is producing a large area of
disorganized showers and thunderstorms that extends several hundred
miles south of the coast of southern Mexico. Environmental
conditions appear conducive for development of this disturbance, and
a tropical depression is likely to form late this week while the
system moves west-northwestward or northwestward at 5 to 10 mph,
near the coast of southwestern Mexico. Regardless of development,
heavy rains are likely over coastal sections of the Mexican states
of Oaxaca, Guerrero, Michoacan, Colima, and Jalisco during the next
few days, which could cause life-threatening flash floods and mud
slides. Interests in these areas should monitor the progress of
this system through the weekend.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

Forecaster Stewart

[Kingarabian]

00z CMC ends the run with two more systems. Theoretically has Enrique and Felicia. Although this is in the long range, there is ensemble support. If these systems do end up developing, 2021 will have started at a quick pace. Although the lack of storm quality is noticeable.

94E should not have enough time to attempt and become a hurricane, but future Enrique and Felicia could have the chance to become something.

[Yellow Evan]

0z ECMWF hints at a system in 10 days.

[Yellow Evan]

12z GFS brings a hurricane into Guerrero.

[Yellow Evan]

12z CMC and ECMWF have another system by day 10.

[Yellow Evan]

18z GFS moving the timeframe up to development on June 24 and brings a potent hurricane into Michoacan.

[Kingarabian]

Ignoring the storm quality advantage in 1990 and 2018, 2021 so far is producing storms at a similar quick rate.

1990:


2018:


It's possible we'll see elevated activity in the EPAC through September, similar to 1990 and 2017 but nothing near those intensities. I also doubt October will be active.

If we see increased negative anomalies in the subsurface within the next 4 weeks I fully expect the EPAC hurricane season to begin to shut down near mid September.

[aspen]

Ignoring the storm quality advantage in 1990 and 2018, 2021 so far is producing storms at a similar quick rate.

1990:
https://upload.wikimedia.org/wikipedia/en/timeline/6a0a22a0c8bf74e5e314fe4aa47f4ca7.png

2018:
https://upload.wikimedia.org/wikipedia/en/timeline/00182b2c1e62b459d5410470c42c8bc9.png

It's possible we'll see elevated activity in the EPAC through September, similar to 1990 and 2017 but nothing near those intensities. I also doubt October will be active.

If we see increased negative anomalies in the subsurface within the next 4 weeks I fully expect the EPAC hurricane season to begin to shut down near mid September.

With a neutral ENSO slowly transitioning into a cool neutral ENSO through the fall, it’s likely most EPac storms will struggle comparable to last season. Probably lots of slop with the occasional significant TC, again like last year.

[Kingarabian]

Ignoring the storm quality advantage in 1990 and 2018, 2021 so far is producing storms at a similar quick rate.

1990:
https://upload.wikimedia.org/wikipedia/en/timeline/6a0a22a0c8bf74e5e314fe4aa47f4ca7.png

2018:
https://upload.wikimedia.org/wikipedia/en/timeline/00182b2c1e62b459d5410470c42c8bc9.png

It's possible we'll see elevated activity in the EPAC through September, similar to 1990 and 2017 but nothing near those intensities. I also doubt October will be active.

If we see increased negative anomalies in the subsurface within the next 4 weeks I fully expect the EPAC hurricane season to begin to shut down near mid September.

With a neutral ENSO slowly transitioning into a cool neutral ENSO through the fall, it’s likely most EPac storms will struggle comparable to last season. Probably lots of slop with the occasional significant TC, again like last year.

Yeah especially June/July 2020. Filled with terrible systems.


Future Dolores and Enrique will be pretty telling.