2021 Indicators: SST's / SAL / MSLP / Shear / Steering / Instability / Sat Images

[SFLcane]

So, Webb's plots show why the CFS and JMA are blasting the Atlantic with shear it’s basically all that WPAC activity has altered the Rossby wave pattern.

[tolakram]

What's the verification like on that JMA product?

[AutoPenalti]

Which is why it doesn't seem all that ridiculous, CFS and JMA may flip in August as well.

[AlphaToOmega]

If we do not see a -VP cell in the EPAC for ASO, we are guaranteed hyperactivity. From 1980 to 2020, only four seasons had this pattern (one of -VP over Africa and +VP over EPac): 1995, 1996, 2010, and 2020, all of which were hyperactive. If we do see a -VP cell in the EPAC, a hyperactive season is possible but not guaranteed. The hyperactive seasons of 1998, 1999, 2003, 2004, 2005, and 2017 had a -VP in the EPAC for ASO.

[Category5Kaiju]

Was 2008 a year with a rising or sinking VP cell in the EPAC?

[AlphaToOmega]

Was 2008 a year with a rising or sinking VP cell in the EPAC?

Rising EPAC cell

[Category5Kaiju]

Was 2008 a year with a rising or sinking VP cell in the EPAC?

Rising EPAC cell
https://i.postimg.cc/NfMfRYSg/Elcg2w-RN-Y.png

Yeah see this is why imho a rising or sinking EPAC cell alone does not really determine the fate of the Atlantic on how active it could truly get (especially if the cell rises but is weak). There's more to what separates a hyperactive year from a plain active year than just that, and I just don't know if we could really predict with 100% confidence all of such factors in advance.

[Deshaunrob17]

Papin has a interesting twist.

https://twitter.com/pppapin/status/1420762450811572226

That's q good point. A Tutt does not necessarily mean weak or low activity. A tropical cyclone that passes through the Atlantic Basin probably occupies <5 % of the entire Basin. Tutt could be present and there is still a major hurricane nearby.. The atmosphere is a fluid so everything moves. Just as hurricane moves, strengthens and weakness, Tutt moves, strengthens and weakens.. It's more complex than it looks!!!
Take for example Dorian strengthening into a Cat 1 near PR. Now I don t remember a Tutt, but I do remember heck amount of Sal, which was why the models we're never enthusiastic.. We all know how that ended up..

[aspen]

So, Webb's plots show why the CFS and JMA are blasting the Atlantic with shear it’s basically all that WPAC activity has altered the Rossby wave pattern.

A Cat 2 typhoon and a couple of weak storms were able to make that amount of influence to the global weather pattern?

Do you have that plot?

[Category5Kaiju]

So, Webb's plots show why the CFS and JMA are blasting the Atlantic with shear it’s basically all that WPAC activity has altered the Rossby wave pattern.

A Cat 2 typhoon and a couple of weak storms were able to make that amount of influence to the global weather pattern?

Do you have that plot?

Yeah, I wholeheartedly agree. Because that seems quite interesting for that to be the case.

[tolakram]

About this time last year. Different year, but still cancel season. Rather than call out anyone, just review what was being said and determine if anything stands out as maybe spotting an indicator, or didn't matter at all. There's nothing wrong with being wrong, but I would hope that we all can learn year to year what to look for, and maybe what to ignore. This single page doesn't have any smoking guns, but it does have the familiar angst that conditions aren't perfect.

http://www.storm2k.org/phpbb2/viewtopic.php?f=31&t=120763&start=1940

I'm also trying to find the chatter just before Irma came through. A very large TUTT was dominant in the Caribbean until it wasn't.

[tolakram]

Ouch.

2017 indicators thread, Aug 7th: http://www.storm2k.org/phpbb2/viewtopic.php?f=31&t=118642&start=1240

Irma was a cat 3 by Sept 1st.

[Category5Kaiju]

About this time last year. Different year, but still cancel season. Rather than call out anyone, just review what was being said and determine if anything stands out as maybe spotting an indicator, or didn't matter at all. There's nothing wrong with being wrong, but I would hope that we all can learn year to year what to look for, and maybe what to ignore. This single page doesn't have any smoking guns, but it does have the familiar angst that conditions aren't perfect.

http://www.storm2k.org/phpbb2/viewtopic.php?f=31&t=120763&start=1940

I'm also trying to find the chatter just before Irma came through. A very large TUTT was dominant in the Caribbean until it wasn't.

Wasn't personally lurking on this forum back then, but yeah, you are absolutely right. It does seem like there's a general occasional pattern of some hurricane enthusiasts getting nervous that conditions may not be as conducive as expected for the Atlantic when in reality such worries did not really pan out to be legitimate worries. In the end, 2020 saw 30 NSs and did become a hyperactive season, contrary to what some talks at least at the time of your posted link to the 2020 indicators thread mentioned.

Edit: Just went through your link to the 2017 season; I personally did not know people were canceling the season in August of 2017 to that level, wow. What an unexpected turn.

[AlphaToOmega]

Tolakram, it never stops! People try to use any lull of activity to "prove" that a season will be inactive. People try to cancel a season based on one run from one model. This happened even in 2020! The only way for a season to be cancel-proof is to have 5 major MDR hurricanes every month of the year.

[SFLcane]

So, Webb's plots show why the CFS and JMA are blasting the Atlantic with shear it’s basically all that WPAC activity has altered the Rossby wave pattern.

A Cat 2 typhoon and a couple of weak storms were able to make that amount of influence to the global weather pattern?

Do you have that plot?

 https://twitter.com/webberweather/status/1420772727837892611

[USTropics]

Shear is one of the most difficult parameters to forecast, even on an intermediate level (5-10) days. As such, skill level for seasonal shear forecasting is low, and a model blend is typically preferred. As an example, this was the shear forecast last year from the CFS for August and September:




Specifically for the Atlantic lead time weeks 1 and 2, the shear axis forecasted in the western Caribbean ended up being overestimated (and observed displaced more to the north over north GOM and CONUS). The CFS for lead time weeks 3 and 4 was also too aggressive on the prolonged TUTT axis extending into the Caribbean. Instead, we saw Marco and Laura form in the Caribbean.

Here was the CFS forecast for September and observed:



Forecast for lead time weeks 1 and 2 verified well, but again we can see the CFS overestimated wind shear in the Caribbean and most of the tropical Atlantic for lead time weeks 3 and 4.

You can find these types of archive graphics here - https://ncics.org/pub/mjo/archive/

[psyclone]

The most articulate, alphabet soup-loaded dissertation is meaningless and of no value if it expires every few days and is replaced with another mess of jargon with a completely different outcome. Sometimes we're just too smart for our own good. As a simpleton...it's far easier to suggest this: The (real) storms will show up in the latter half of August and beyond because (drumroll....) they usually do. That's just the way it works and it's possible...but highly unlikely this year will be an exception.

[tolakram]

 https://twitter.com/EricBlake12/status/1420788092416495616

[Category5Kaiju]

The most articulate, alphabet soup-loaded dissertation is meaningless and of no value if it expires every few days and is replaced with another mess of jargon with a completely different outcome. Sometimes we're just too smart for our own good. As a simpleton...it's far easier to suggest this: The (real) storms will show up in the latter half of August and beyond because (drumroll....) they usually do. That's just the way it works and it's possible...but highly unlikely this year will be an exception.

Yep, sometimes it's best to keep things simple, and in this case, I expect activity to ramp up mid to late August. Unless I see otherwise or if reliable signs point otherwise as the time gets closer, I'm going to go with Occam's razor here and say that we should still expect an above average season starting later in August (with our first major forming by then as well, as many other seasons recently have shown).

[SFLcane]

https://twitter.com/EricBlake12/status/1420788092416495616?s=20

Models are still adjusting.