2021 EPAC Season

[aspen]

12z GFS has major after major to end its run:
https://i.imgur.com/ZOtt0Xv.gif

That gif pretty much sums up long-range GFS MJO bias. I highly doubt those last two storms even form, let alone become majors; the MJO will be focused on the Atlantic by mid-August, but the GFS keeps it on the EPac.

[Kingarabian]

3 mayors wont verify.

Yeah maybe 2 max. There's been good consistent EPS support for 2 systems in the long range including the newly designated disturbance. Not much EPS support for 3rd long range system yet.

[Kingarabian]

12z GFS has major after major to end its run:
https://i.imgur.com/ZOtt0Xv.gif

That gif pretty much sums up long-range GFS MJO bias. I highly doubt those last two storms even form, let alone become majors; the MJO will be focused on the Atlantic by mid-August, but the GFS keeps it on the EPac.

I'm not saying they're gonna become majors as the GFS hints, but the modeling has always supported at least 2 more systems in the long range to cap off this surge in EPAC TC activity.

[weeniepatrol]

12z GFS has major after major to end its run

more like major bust after major bust

[Kingarabian]

Strong ensemble signal for two significant TCs:





The only thing potentially limiting these will be sneaky mid level shear and continental dry air off of Mexico which the models have a hard time figuring out.

[ElectricStorm]

Well whichever one of these ends up being Jimena is going to have some high expectations. Each storm with that name since 1979 has been a Cat 4 except for 2003 which was a Cat 2. So it better be strong lol

[Category5Kaiju]

Well whichever one of these ends up being Jimena is going to have some high expectations. Each storm with that name since 1979 has been a Cat 4 except for 2003 which was a Cat 2. So it better be strong lol

If you think that is "high expectations," you should look at Kenneth. All 4 EPAC Kenneths peaked at a Cat 4, and this could also include Cyclone Kenneth from 2019 in the SW Indian Ocean, which was also a Cat 4. 2023 is the year though for that..

[gatorcane]

It is long-range but the GFS has two more after the major it has been showing a week from now:

[dexterlabio]

Are we not expecting the major canes in EPAC to verify because it's La Niña and the Atlantic should be the favorable one?

[Category5Kaiju]

Are we not expecting the major canes in EPAC to verify because it's La Niña and the Atlantic should be the favorable one?

In essence, yes. Not to mention we are in a -PDO and -PMM phase too, so the GFS showing major hurricanes continously produced (very close to Mexico as well) despite an incoming -ENSO or La Nina (which was something characteristic of the 1980s and early 1990s) is very unlikely imho.

[Yellow Evan]

Are we not expecting the major canes in EPAC to verify because it's La Niña and the Atlantic should be the favorable one?

It's because the GFS is pretending the African standing wave pattern dominant the last several years and forecast to be dominant by the ECMWF doesn't exist.The GFS instead is showing an American standing wave-like pattern which favors rising motion over the Americas and is sometimes that you'd expect in the 1980s or early 1990s. This isn't the first time this has been an issue with the GFS and in fact it's occasionally been an issue as far back as I can remember.

[AxaltaRacing24]

Are we not expecting the major canes in EPAC to verify because it's La Niña and the Atlantic should be the favorable one?

Yes. and combine that with the trend of recent EPAC storms underperforming, which adds fuel to that hypothesis. It is also clear that the GFS has shown this bias towards this basin for the last couple seasons, as you can see it pumping out hurricanes nearly every single run. Much of this is due to a proven VP bias, which is very likely to bust.

[Kingarabian]

Are we not expecting the major canes in EPAC to verify because it's La Niña and the Atlantic should be the favorable one?

There's pessimism due to a couple of systems near Mexico not becoming as strong as expected. However since we're entering August and there's strong ensemble and lingering favorable MJO support, a couple of TC's forming near 29C waters and attempting to become majors in the next 2 weeks is not impossible.

[Chris90]

I think it's possible to pull off another major in this active streak, and while I think 2 is unlikely I don't think it's impossible. If these storms can stay far enough east to take advantage of the warmer ssts they might have a shot. Anything that shoots off to the west though has to stay low enough to keep warm, the 26C isotherm isn't as far north as it has been in the recent past with the bigger EPAC seasons, and storms this season don't seem to be handling marginal ssts as well as EPAC storms sometimes do.

Do I think the Atlantic is going to take over as the dominant basin overall this year? Yes, but we have to remember the EPAC average is 4 majors a season and it's the more dominant basin overall when you look at long term averages. I'd expect at the very least one more major this season over on the Pacific side and another 2-3 would be in line with averages. I'd say there's at least a 50/50 shot that one of those modeled majors verifies.

[ElectricStorm]

0z GFS continues to pump out strong systems in the EPAC...
As much as I would love a parade of EPAC long-tracking majors (OTS of course), I can't really get too excited even though the GFS really wants me to. I remember the GFS had this problem last year, where it would show strong EPAC systems, yet most of them never formed.

That being said however, the EPAC can still produce some big ones even in -ENSO years, and since the Atlantic hasn't taken over yet, I think there's a decent chance one of these actually develops and makes a run at a major.

[aspen]

This is quite strange. Despite a developing -ENSO, the EPac has done better than expected. Named storms, hurricanes, majors, ACE, and NS/H/MH days are running near average. NS are a little above average, and ACE is a little below average. The key word is better, because that doesn’t mean the season has been free from struggle storms, but it’s more impressive than last year, which didn’t reach the G storm until late August.

[dexterlabio]

I may be the only one to think this but using the ENSO state to predict the near-term tropical cyclone activity in any basin could mislead us. On the top of my head, 2011 is a second-year La Niña that didn't suppress the EPAC hurricane season that much. If I'm not mistaken, EPAC got more than 4 major canes that year. If we follow through the mindset of "oh it's cold ENSO, then this basin should be dead this year" then the existence of such a year would baffle us and lead us to believe that the climate is being "strange." But the thing is there are little things working under our radar that can offer us a clear explanation.

ENSO might have a general effect on tropical cyclone formation and behavior, but there might be other seasonal (or even day-to-day) variabilities at play that could spell quite a difference.

[Deshaunrob17]

I may be the only one to think this but using the ENSO state to predict the near-term tropical cyclone activity in any basin could mislead us. On the top of my head, 2011 is a second-year La Niña that didn't suppress the EPAC hurricane season that much. If I'm not mistaken, EPAC got more than 4 major canes that year. If we follow through the mindset of "oh it's cold ENSO, then this basin should be dead this year" then the existence of such a year would baffle us and lead us to believe that the climate is being "strange." But the thing is there are little things working under our radar that can offer us a clear explanation.

ENSO might have a general effect on tropical cyclone formation and behavior, but there might be other seasonal (or even day-to-day) variabilities at play that could spell quite a difference.

Exactly!!! Totally agree with this!!!

[Yellow Evan]

2011’s La Niña event was CPAC based which allowed for some rising motion to persist further east and vertical instability was much higher than most years.



I do agree that ENSO while a good indicator of annual activity is less predictable on the monthly level, however. At the same time, this is a repeated bias in the GFS during an MJO passage that has only gotten worse in recent years and needs to be rectified. I’d be a lot more on board with a hurricane in 10 days if the ECMWF was showing one as well, for instance.

[cycloneye]

Here is the major GFS has.

An area of low pressure is expected to develop a few hundred
miles south of the southern coast of Mexico by the end of the week.
Environmental conditions are forecast to be conducive for gradual
development thereafter while the system moves west-northwestward at
10 to 15 mph, just offshore and parallel to the coast of
southwestern Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.