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

[tolakram]

Is the conclusion obvious? SST's are a fairly small part of predicting seasonal activity? As long as SST's are warm enough to support tropical cyclones then upper air patterns are probably the most critical ingredient. This holds unless SST's are well below normal, in my opinion. Well above normal SST's might aid in quick spinups of storms, but other factors will be more important to determine the strength and lifespan. Combine above normal SST's and very favorable upper air patterns and maybe you get an above normal season, but I don't think anyone here, nor any expert, can claim to understand what it takes to cross the man made threshold of hyperactive.

For all of this, we're setting the odds. Higher SST's increase the odds by some unknown percentage. More waves increase the odds. Certain patterns may or may not increase the odds, etc. Unfortunately, even though it seems like we have a lot of data, we really don't. If we did the forecasts that use hindcasting to try and predict future results would be very accurate. They aren't. We still have seasons that surprise us and add to the data.

So where this ends up, unfortunately, is a lot of amateurs make predictions. Some of those will come true, but not because their predictions were correct. That's the key point to understand in all of this, and why repeated verification is SO important. My opinion, of course.

[Category5Kaiju]

For some reason, despite a La Niña and warmer than normal MDR SSTs, the CFSv2 is predicting above-normal wind shear over the MDR and Caribbean for ASO.

https://i.imgur.com/OlitqQP_d.webp?maxwidth=640&shape=thumb&fidelity=medium

Is that configuration even possible? That literally defies the reason why a La Nina is naturally a plus for above average Atlantic activity.

[CyclonicFury]

For some reason, despite a La Niña and warmer than normal MDR SSTs, the CFSv2 is predicting above-normal wind shear over the MDR and Caribbean for ASO.

https://i.imgur.com/OlitqQP_d.webp?maxwidth=640&shape=thumb&fidelity=medium

Is that configuration even possible? That literally defies the reason why a La Nina is naturally a plus for above average Atlantic activity.

Apparently it showed something similar last year around this time, which verified poorly. It could be some sort of model bias related to MJO progression.

[AlphaToOmega]

For some reason, despite a La Niña and warmer than normal MDR SSTs, the CFSv2 is predicting above-normal wind shear over the MDR and Caribbean for ASO.

https://i.imgur.com/OlitqQP_d.webp?maxwidth=640&shape=thumb&fidelity=medium

Is that configuration even possible? That literally defies the reason why a La Nina is naturally a plus for above average Atlantic activity.

Below-average shear in the EPAC despite La Nina

This is why I do not use CFSv2 for long-term climate forecasts

[AutoPenalti]

For some reason, despite a La Niña and warmer than normal MDR SSTs, the CFSv2 is predicting above-normal wind shear over the MDR and Caribbean for ASO.

https://i.imgur.com/OlitqQP_d.webp?maxwidth=640&shape=thumb&fidelity=medium

Is that configuration even possible? That literally defies the reason why a La Nina is naturally a plus for above average Atlantic activity.

It was discussed some pages back that the TUTT associated with a stronger EASJ and Rossby Wave may increase shear in the MDR.

[aspen]

For some reason, despite a La Niña and warmer than normal MDR SSTs, the CFSv2 is predicting above-normal wind shear over the MDR and Caribbean for ASO.

https://i.imgur.com/OlitqQP_d.webp?maxwidth=640&shape=thumb&fidelity=medium

Is that configuration even possible? That literally defies the reason why a La Nina is naturally a plus for above average Atlantic activity.

Apparently it showed something similar last year around this time, which verified poorly. It could be some sort of model bias related to MJO progression.
https://i.imgur.com/LCsocok_d.webp?maxwidth=640&shape=thumb&fidelity=medium
https://i.imgur.com/5yh0Zbi_d.webp?maxwidth=640&shape=thumb&fidelity=medium

There was that time frame in the first half of September where shear was high due to that TUTT pumped by Maysak and Haishen in the WPac, so it only partially verified. However, shear wasn’t there when Teddy blew up into a Cat 4, and the later MDR storms struggled due to coming off of Africa too far north.

[MarioProtVI]

CFSv2, just like the CanSIPS and JMA, finally suggests a favorable pattern for August:
https://i.postimg.cc/P5mPZCZ0/cfs-mon-01-chi200-global-1.png

But!?

https://i.postimg.cc/9MWx19Pq/FBF62068-5145-42-E3-9-FB5-4-CE66083234-B.jpg

CFS has a known bias to create pseudo El Niño conditions regardless of ENSO. Last year it predicted same thing and didn’t verify. So not buying CFS

[AlphaToOmega]

I made a spreadsheet of hurricane season activity and certain patterns (1980-2020):
https://docs.google.com/spreadsheets/d/1IiT2RLzZsymZ4Rc1WQEIvhul92egsnjFciaBGxkdSbU/edit?usp=sharing

[aspen]

CFSv2, just like the CanSIPS and JMA, finally suggests a favorable pattern for August:
https://i.postimg.cc/P5mPZCZ0/cfs-mon-01-chi200-global-1.png

Looks like the WPAC is going to have some trouble generating some powerful typhoons should that verify. Lots of sinking motion over the basin

That could prevent storms like Maysak and Haishen, which recurve at high latitudes and help create a strong TUTT that shreds MDR systems like last year. If it wasn’t for that, 2020 likely would have had a more impressive MDR than just Teddy and a few tropical storms that either fizzled out or peaked in the subtropics.

[Category5Kaiju]

CFSv2, just like the CanSIPS and JMA, finally suggests a favorable pattern for August:
https://i.postimg.cc/P5mPZCZ0/cfs-mon-01-chi200-global-1.png

Looks like the WPAC is going to have some trouble generating some powerful typhoons should that verify. Lots of sinking motion over the basin

That could prevent storms like Maysak and Haishen, which recurve at high latitudes and help create a strong TUTT that shreds MDR systems like last year. If it wasn’t for that, 2020 likely would have had a more impressive MDR than just Teddy and a few tropical storms that either fizzled out or peaked in the subtropics.

While I only learned it last year, I never knew that even during a La Nina year the WPAC's storm tracks could actually impact the conditions in the Atlantic. Pretty cool imho to say the least.

[SFLcane]

I made a spreadsheet of hurricane season activity and certain patterns (1980-2020):
https://docs.google.com/spreadsheets/d/1IiT2RLzZsymZ4Rc1WQEIvhul92egsnjFciaBGxkdSbU/edit?usp=sharing

Where does this year fall?

[AlphaToOmega]

I made a spreadsheet of hurricane season activity and certain patterns (1980-2020):
https://docs.google.com/spreadsheets/d/1IiT2RLzZsymZ4Rc1WQEIvhul92egsnjFciaBGxkdSbU/edit?usp=sharing

Where does this year fall?

Based on CanSIPS, 2021 is expected to have +AMO, +TNA, -ENSO, -PDO, -VP over Africa, and +VP over EPac, just like 2020 and 2010 (all of this is for ASO).

[SFLcane]

I made a spreadsheet of hurricane season activity and certain patterns (1980-2020):
https://docs.google.com/spreadsheets/d/1IiT2RLzZsymZ4Rc1WQEIvhul92egsnjFciaBGxkdSbU/edit?usp=sharing

Where does this year fall?

Based on CanSIPS, 2021 is expected to have +AMO, +TNA, -ENSO, -PDO, -VP over Africa, and +VP over EPac, just like 2020 and 2010 (all of this is for ASO).

+AMO? The +VP over the East Pacific is a stretch.

[AlphaToOmega]

That is a hot MDR!

[Category5Kaiju]

Also I would like to say this as I feel it is a very intriguing point, but when it comes down to having a "hyperactive season," having even at least only two or so storms but with each being an impressive long tracker can be enough to contribute roughly 100 or slightly more ACE to the hurricane season. For instance, I could have a season like 2020 (which produced 180 ACE) and a hypothetical season featuring only three NSs but with the three storms being the top ACE storms (Ivan, Irma, and Isabel), and this would amount to nearly 198 ACE.

[aspen]

Where does this year fall?

Based on CanSIPS, 2021 is expected to have +AMO, +TNA, -ENSO, -PDO, -VP over Africa, and +VP over EPac, just like 2020 and 2010 (all of this is for ASO).

+AMO? The +VP over the East Pacific is a stretch.

Well, it’s certainly not looking -AMO anymore, and most of the EPac has +VP anomalies except for one -VP cell off of the Mexican coast. If that cell dies off or never verifies, the EPac will be suppressed.

[AlphaToOmega]

Based on CanSIPS, 2021 is expected to have +AMO, +TNA, -ENSO, -PDO, -VP over Africa, and +VP over EPac, just like 2020 and 2010 (all of this is for ASO).

+AMO? The +VP over the East Pacific is a stretch.

Well, it’s certainly not looking -AMO anymore, and most of the EPac has +VP anomalies except for one -VP cell off of the Mexican coast. If that cell dies off or never verifies, the EPac will be suppressed.

Was it ever -AMO? The last time the AMO was negative was February 2019.

https://psl.noaa.gov/data/correlation/amon.us.long.data

[JPmia]

I made a spreadsheet of hurricane season activity and certain patterns (1980-2020):
https://docs.google.com/spreadsheets/d/1IiT2RLzZsymZ4Rc1WQEIvhul92egsnjFciaBGxkdSbU/edit?usp=sharing

Great work… would be interesting to see that go back further in time.. but you can see a pattern with the colors .. especially with what is projected for this season.

[Category5Kaiju]

 https://twitter.com/AndyHazelton/status/1420454337050992643




Andy Hazelton looks to be on fire today with regards to Atlantic hurricane discussions despite the lull!

[cycloneye]

The West Pacific monsoon relocates into the Atlantic.

 https://twitter.com/WxTca/status/1420457418853601286




 https://twitter.com/cyclonicwx/status/1420458153410433025