2021 EPAC Season

[Yellow Evan]

This setup is just as bad as 2020, which is saying something.

[cycloneye]

An area of low pressure is expected to form in a few days a couple
of hundred miles offshore of the coast of southwestern Mexico.
Environmental conditions are expected to be conducive for gradual
development of this system thereafter, and a tropical depression
could form late this week or over the weekend while it moves slowly
northwestward, roughly parallel to the southwestern coast of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...50 percent.

[Yellow Evan]

12z GFS and ECMWF no longer really develop this.

[galaxy401]

12z GFS and ECMWF no longer really develop this.

Felt like I've been hearing those words a bunch of times already (not a jab at you or anything). That summarizes what this EPAC season has been so far: Models sniff out something then drop it when it gets close-range.

[Kingarabian]

[url]https://cdn.discordapp.com/attachments/733552978572869632/853976747800395776/image1.gif[url]

This setup is just as bad as 2020, which is saying something.

I'm not sure. I think we need to see complete June VP200 data first, and halfway through June, current analysis shows an abundant amount of -VP200 anomalies over the EPAC. It's a similar look to 2019 and 2020 over Africa and South America. But there's much more rising motion near the dateline compared to 2020 and 2019 from April through May. Even if we include March. That's the most important give away despite the sinking motion over the EPAC.


Even though there's sinking motion over the EPAC, pre season anomalous sinking motion over parts of EPAC can also be found in recent weak-moderate +ENSO events. (2006, 2009, 2014, 2018).


Even though those years had much more rising motion over South America compared to 2021, so did La Nina years in 2008, 2010, and 2011.


That being I said, so far I think the current VP200 configuration is a lot better than 2020 and 2019.

[Kingarabian]

With the operational models flip flopping quite a bit so far I think ensembles will tell the story better.

12Z EPS still favors development over that circled area:


Also three named systems and we still haven't seen a basic hurricane...

[Yellow Evan]

[url]https://cdn.discordapp.com/attachments/733552978572869632/853976747800395776/image1.gif[url]

This setup is just as bad as 2020, which is saying something.

I'm not sure. I think we need to see complete June VP200 data first, and halfway through June, current analysis shows an abundant amount of -VP200 anomalies over the EPAC. It's a similar look to 2019 and 2020 over Africa and South America. But there's much more rising motion near the dateline compared to 2020 and 2019 from April through May. Even if we include March. That's the most important give away despite the sinking motion over the EPAC.
https://i.imgur.com/yFrBOoQ.gif

Even though there's sinking motion over the EPAC, pre season anomalous sinking motion over parts of EPAC can also be found in recent weak-moderate +ENSO events. (2006, 2009, 2014, 2018).
https://i.imgur.com/nOypjvv.png

Even though those years had much more rising motion over South America compared to 2021, so did La Nina years in 2008, 2010, and 2011.
https://i.imgur.com/mYVBA48.png

That being I said, so far I think the current VP200 configuration is a lot better than 2020 and 2019.

Rising motion near the dateline just shifts WPAC activity more east, but probably won't affect the EPAC too much. 2019 also had a -PV over the basin despite its slow start, which this year did not. 2020 did not feature any -PV at all (even 2007 did and only 1996/2010 didn’t since the last active era) so if 2021 actually does, that’d be an an improvement (I'm not comfortable projecting on whether it will but this isn't a great start). Also worth noting 2021 has an ASW setup, which isn't the most favorable, though of course 2020 had this as well.

[Yellow Evan]

Can't plot vertical instability (which according to charts is below average but I can't compare to previous years) so this is the closest thing I can produce.

For comparison,



Select quantity over quality seasons.



Select quality over quantity seasons.

Given we have three named storms and zero hurricanes, this finding is unsurprising. Unless this change, I'd be quite surprised if we got more than 3 majors but I wouldn't be surprised if we ended up with 17-20 named storms much like recent years.

[cycloneye]

An area of low pressure is expected to form later this week a couple
of hundred miles offshore of the coast of southwestern Mexico.
Environmental conditions are expected to be conducive for gradual
development of this system thereafter, and a tropical depression
could form by this weekend while it moves slowly northwestward,
roughly parallel to the southwestern coast of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...50 percent.

[Kingarabian]

It sure is hard to find a concrete analog for the current VP200 configuration.

Maybe 1990 isn't a bad analog:

-VP200 (rising motion extending to 150E and sinking motion over the EPAC)


SSTs:


Subsurface:

[aspen]

It sure is hard to find a concrete analog for the current VP200 configuration.

Maybe 1990 isn't a bad analog:

-VP200 (rising motion extending to 150E and sinking motion over the EPAC)
https://i.imgur.com/M5iYMzZ.png

SSTs:
https://i.imgur.com/YgpCEyp.png

Subsurface:
https://i.imgur.com/S5UeIff.png

1990 was one of the most active EPac seasons on record. That doesn’t mean this year will be nearly as active; I just find it surprising that such an active season had a kind of similar setup to this season, which seems to be gearing up to be quantity>quality with many slop storms like 2020.

[Yellow Evan]

FWIW 1990 did also have early May activity to 2021 with a storm in a similar region compared to 2021 and the SST profiles do much. 1990 was a year that an El Nino tried to form after a prolonged La Nina, and its PDO was initially - but flipped to + later on I believe. I don't think it's unreasonable to believe this year could have similarities in terms of storm tracks, with a more east based concentration. I do think it's unreasonable to think 16 hurricanes will form, though none of the parameters you posted aside from perhaps -VP anomaly (I need to look further) really affect that.

[Kingarabian]

FWIW 1990 did also have early May activity to 2021 with a storm in a similar region compared to 2021 and the SST profiles do much. 1990 was a year that an El Nino tried to form after a prolonged La Nina, and its PDO was initially - but flipped to + later on I believe. I don't think it's unreasonable to believe this year could have similarities in terms of storm tracks, with a more east based concentration. I do think it's unreasonable to think 16 hurricanes will form, though none of the parameters you posted aside from perhaps -VP anomaly (I need to look further) really affect that.

Yeah I strongly doubt we'll see anything close to 1990's hurricane numbers. Super weird how 1990 got that many hurricanes in the first place when you consider where all the rising motion was situated during ASO:


Such an odd year.

[Yellow Evan]

FWIW 1990 did also have early May activity to 2021 with a storm in a similar region compared to 2021 and the SST profiles do much. 1990 was a year that an El Nino tried to form after a prolonged La Nina, and its PDO was initially - but flipped to + later on I believe. I don't think it's unreasonable to believe this year could have similarities in terms of storm tracks, with a more east based concentration. I do think it's unreasonable to think 16 hurricanes will form, though none of the parameters you posted aside from perhaps -VP anomaly (I need to look further) really affect that.

Yeah I strongly doubt we'll see anything close to 1990's hurricane numbers. Super weird how 1990 got that many hurricanes in the first place when you consider where all the rising motion was situated during ASO:
https://i.imgur.com/YxHwGVJ.png

Such an odd year.

Most of the 1980's seasons featured an American standing wave and +VP over Africa. 1990 seems to also fits that bill even if it was displaced a bit to the east. And PDO itself was mostly positive though not crazy high and dipped by winter.

1990 -0.30 -0.65 -0.62 0.27 0.44 0.44 0.27 0.11 0.38 -0.69 -1.69 -2.23

[NotSparta]

FWIW 1990 did also have early May activity to 2021 with a storm in a similar region compared to 2021 and the SST profiles do much. 1990 was a year that an El Nino tried to form after a prolonged La Nina, and its PDO was initially - but flipped to + later on I believe. I don't think it's unreasonable to believe this year could have similarities in terms of storm tracks, with a more east based concentration. I do think it's unreasonable to think 16 hurricanes will form, though none of the parameters you posted aside from perhaps -VP anomaly (I need to look further) really affect that.

Yeah I strongly doubt we'll see anything close to 1990's hurricane numbers. Super weird how 1990 got that many hurricanes in the first place when you consider where all the rising motion was situated during ASO:
https://i.imgur.com/YxHwGVJ.png

Such an odd year.

Most of the 1980's seasons featured an American standing wave and +VP over Africa. 1990 seems to also fits that bill even if it was displaced a bit to the east. And PDO itself was mostly positive though not crazy high and dipped by winter.

1990 -0.30 -0.65 -0.62 0.27 0.44 0.44 0.27 0.11 0.38 -0.69 -1.69 -2.23

Was about to say this. The American standing wave was a huge thing at the time, basically like the African standing wave for the EPAC. Let the basin print out seemingly endless active seasons in the 1980s and early 1990s. Kept -ENSO away in general during the early 90s too

[cycloneye]

GFS has a monster on long range.

[Yellow Evan]

GFS has a monster on long range.

https://i.imgur.com/XkGMxQT.jpg

There goes any chance of a monster happening if the GFS is showing one.

[Yellow Evan]

A broad area of low pressure is expected to form later this week a
couple of hundred miles offshore of the coast of southwestern
Mexico. Environmental conditions are expected to be generally
favorable for gradual development of this system thereafter, and a
tropical depression could form by this weekend while it moves slowly
northwestward, roughly parallel to the southwestern coast of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...40 percent.

[cycloneye]

A large area of disorganized showers and thunderstorms located a few
hundred miles south of southern Mexico and Guatemala are associated
with a westward-moving tropical wave and a broad area of low
pressure. An area of low pressure is expected to form along this
wave later this week. Environmental conditions are expected to be
favorable for gradual development of this system, and a tropical
depression could form by this weekend while it moves slowly
northwestward, roughly parallel to the southwestern coast of Mexico.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...medium...60 percent.

[Kingarabian]

The 10/60 has a great shot at developing so long it keeps distance from the Mexican coast. Proximity to land is going to be the biggest question. But it has very good and consistent EPS support.

Looking ahead, EPS is showing a favorable EPAC atmosphere to close out June with a strong concentrated area of -VP200 anomalies.

www.weathermodels.com

10/60 system:



Future activity:


www.weathermodels.com