2025-2026 ENSO

[snowman19]

I made this graph last year, it's a smoothed out AMO index since it went positive in 1995. It appears that we still seem to be in a rising phase, over the long term. 

Also, the NAO has been very positive May-Aug, just like last year. Such +NAO in the warm season has a -0.3 SSTA correlation in the south-central Atlantic. A lot of the cool water this year is because of such a strong +NAO... It's been positive 8 of the last 9 months. If the NAO had been negative 8/9 months, you'd be seeing some very warm SSTAs in the Tropical Atlantic, and probably more activity this hurricane season. 

And on the PAC side, this -PDO cycle has been much stronger than the last one (1940’s-1970’s). I’ve seen a few articles blaming the record low arctic sea ice on this -PDO cycle

[snowman19]

The unusual westward MJO propagation continues

[GaWx]

 The unusual clockwise dominated MJO rotation that started Sept 1st is continuing and progged to keep going through at least Oct 6th per the images below. So, it went from phase 5 (inside) on 8/31 back to ph 2 9/2-8. It temporarily went forward to ph 3 for 3 days but then backtracked across 2 then 1 and then 8. It’s forecasted to continue backtracking through 7, 6, 5, 4, 3, 2, 1, and 8.

 I just looked at MJO diagrams for the 2nd half of each year back to 1975 and couldn’t find anything comparable:

[snowman19]

20 minutes ago, GaWx said:

 The unusual clockwise dominated MJO rotation that started Sept 1st is continuing and progged to keep going through at least Oct 6th per the images below. So, it went from phase 5 (inside) on 8/31 back to ph 2 9/2-8. It temporarily went forward to ph 3 for 3 days but then backtracked across 2 then 1 and then 8. It’s forecasted to continue backtracking through 7, 6, 5, 4, 3, 2, 1, and 8.

 I just looked at MJO diagrams for the 2nd half of each year back to 1975 and couldn’t find anything comparable:

The MJO waves have also been low amplitude unlike last year at this time when we were seeing strong waves and are projected to stay that way

[snowman19]

[BlizzardWx]

8 hours ago, snowman19 said:

The MJO waves have also been low amplitude unlike last year at this time when we were seeing strong waves and are projected to stay that way

I wonder if this will continue into winter. Any thoughts? I know a lot of our troubles the last ten years have been from too much MJO 4-6. So maybe no real MJO signal would be a plus? 

[snowman19]

9 hours ago, BlizzardWx said:

I wonder if this will continue into winter. Any thoughts? I know a lot of our troubles the last ten years have been from too much MJO 4-6. So maybe no real MJO signal would be a plus? 

In theory, a -QBO should destabilize the tropical tropopause and cause a stronger, more robust MJO and on equator forcing/convection. Maybe this erratic behavior with the westward propagations and weak, low amplitude MJO waves is only temporary and will change as we go deeper into fall? Strong -IOD/La Niña playing a role? I’m honestly not sure besides saying to take a wait and see approach 

[Stormchaserchuck1]

18 hours ago, snowman19 said:

And on the PAC side, this -PDO cycle has been much stronger than the last one (1940’s-1970’s). I’ve seen a few articles blaming the record low arctic sea ice on this -PDO cycle

I would think warmer water in the Gulf of Alaska and Bering Strait would be a cause of more arctic ice melt, which is more +PDO... but the arctic ice melt has completely gone bare on the Pacific side of the Arctic circle, and the PDO has gone to new record low levels during and after that time, so something may be connecting them.. although maybe not directly

[Daniel Boone]

13 hours ago, snowman19 said:

In theory, a -QBO should destabilize the tropical tropopause and cause a stronger, more robust MJO and on equator forcing/convection. Maybe this erratic behavior with the westward propagations and weak, low amplitude MJO waves is only temporary and will change as we go deeper into fall? Strong -IOD/La Niña playing a role? I’m honestly not sure besides saying to take a wait and see approach 

Yeah. As it stands now, the influence of the QBO on this Winter is a Mystery with the other Factors you mentioned and Other's in play.

[40/70 Benchmark]

23 minutes ago, Daniel Boone said:

Yeah. As it stands now, the influence of the QBO on this Winter is a Mystery with the other Factors you mentioned and Other's in play.

I'll be pretty suprised if we don't see at least one round of significant blocking.

[Daniel Boone]

7 hours ago, 40/70 Benchmark said:

I'll be pretty suprised if we don't see at least one round of significant blocking.

Yeah, me too.

[Stormchaserchuck1]

Warmer October still look likely. Long range models have +EPO, which I have stressed is a connected -PDO pattern, strongly, in October. What I mean is the PDO as an independent variable, not connected to 0-time conditions and influenced by them. It's working for the 2nd year in a row, as the PDO has been strongly negative in both of those October's. 

[snowman19]

3 hours ago, Stormchaserchuck1 said:

Warmer October still look likely. Long range models have +EPO, which I have stressed is a connected -PDO pattern, strongly, in October. What I mean is the PDO as an independent variable, not connected to 0-time conditions and influenced by them. It's working for the 2nd year in a row, as the PDO has been strongly negative in both of those October's. 

Very good call. It also looks dry as a bone which obviously is not good at all given the ongoing drought since the end of July

[snowman19]

@Gawx Starting to wonder if we are seeing a secondary peak in this solar cycle

[bluewave]

4 hours ago, Stormchaserchuck1 said:

Warmer October still look likely. Long range models have +EPO, which I have stressed is a connected -PDO pattern, strongly, in October. What I mean is the PDO as an independent variable, not connected to 0-time conditions and influenced by them. It's working for the 2nd year in a row, as the PDO has been strongly negative in both of those October's. 

I think the record cold in Siberia creating the tight gradient between the record SSTs south of the Aleutians is helping this very strong shift to +EPO. This is following a similar pattern of recent years. Currently the Aleutians are experienceing a 4 sigma jet max helping to dig the +EPO trough and pump the warm ridge over North America. So as we have seen in recent years it tough to maintain a -EPO indefinitely. This EPO reversal was among the strongest we have seen from September into October.

4 sigma jet max near Aleutians

Strong EPO reversal

https://downloads.psl.noaa.gov/Public/map/teleconnections/epo.reanalysis.t10trunc.1948-present.txt

025 09 01 -195.59
2025 09 02 -217.86
2025 09 03 -189.23
2025 09 04 -134.91
2025 09 05 -108.24
2025 09 06  -90.21
2025 09 07  -71.66
2025 09 08  -37.71
2025 09 09    3.25
2025 09 10   39.61
2025 09 11   71.15
2025 09 12   90.96
2025 09 13   97.24
2025 09 14   92.25
2025 09 15   53.53
2025 09 16   -6.59
2025 09 17  -20.75
2025 09 18  -29.60
2025 09 19   33.92
2025 09 20  133.17
2025 09 21  158.66

 

 

 

[40/70 Benchmark]

There are some posters you just know are never going to deliver good news, and if they ever do, it will be measured and delivered with ample caveats. Seem them post....brace first, read later-

[snowman19]

[donsutherland1]

With respect to the EPO, the swing from the minimum value during the first half of September to the maximum value (so far) for the second half of September is the fourth largest on record.

All of the prior 10 biggest such cases occurred during the evolution toward either La Niña or Neutral-Cool ENSO winters.

The composite temperature anomalies for the Neutral-Cool ENSO Winters:

The composite temperature anomalies for the La Niña Winters:

However, warmth is not a slam dunk for the Northeast/Great Lakes. Winters 1964-65 and 1970-71 were cold in the Northeast, Great Lakes, and Northern Plains. Winters 2007-08 and 2020-2021 were cold in the Central Plains.

Finally, the sample size is limited to 10 extreme EPO cases. 

 

[40/70 Benchmark]

31 minutes ago, donsutherland1 said:

With respect to the EPO, the swing from the minimum value during the first half of September to the maximum value (so far) for the second half of September is the fourth largest on record.

All of the prior 10 biggest such cases occurred during the evolution toward either La Niña or Neutral-Cool ENSO winters.

The composite temperature anomalies for the Neutral-Cool ENSO Winters:

The composite temperature anomalies for the Neutral-Cool ENSO Winters:

However, warmth is not a slam dunk for the Northeast/Great Lakes. Winters 1964-65 and 1970-71 were cold in the Northeast, Great Lakes, and Northern Plains. Winters 2007-08 and 2020-2021 were cold in the Central Plains.

Finally, the sample size is limited to 10 extreme EPO cases. 

 

Interesting....some of my heavy-hitter analogs on that list.

[chris21]

1 hour ago, donsutherland1 said:

With respect to the EPO, the swing from the minimum value during the first half of September to the maximum value (so far) for the second half of September is the fourth largest on record.

All of the prior 10 biggest such cases occurred during the evolution toward either La Niña or Neutral-Cool ENSO winters.

The composite temperature anomalies for the Neutral-Cool ENSO Winters:

The composite temperature anomalies for the Neutral-Cool ENSO Winters:

However, warmth is not a slam dunk for the Northeast/Great Lakes. Winters 1964-65 and 1970-71 were cold in the Northeast, Great Lakes, and Northern Plains. Winters 2007-08 and 2020-2021 were cold in the Central Plains.

Finally, the sample size is limited to 10 extreme EPO cases. 

 

Hey Don! I think the second chart should be for La Niña and not neutral-cool.

[donsutherland1]

1 minute ago, chris21 said:

Hey Don! I think the second chart should be for La Niña and not neutral-cool.

Yes, that's correct. I fixed it..

[40/70 Benchmark]

https://easternmassweather.blogspot.com/2025/09/guidance-aligning-with-eastern-mass.html

Preliminary composite out..subject to changes next 6 weeks.

DJFM 2025-2026

[anthonymm]

9 hours ago, Stormchaserchuck1 said:

Warmer October still look likely. Long range models have +EPO, which I have stressed is a connected -PDO pattern, strongly, in October. What I mean is the PDO as an independent variable, not connected to 0-time conditions and influenced by them. It's working for the 2nd year in a row, as the PDO has been strongly negative in both of those October's. 

So summer but with lower dews. Cool cool.

[anthonymm]

38 minutes ago, 40/70 Benchmark said:

https://easternmassweather.blogspot.com/2025/09/guidance-aligning-with-eastern-mass.html

Preliminary composite out..subject to changes next 6 weeks.

DJFM 2025-2026

I have to say, if you're a snow hater in sne or the mid atlantic it's been an amazing string of years! Pattern looks to continue.

[40/70 Benchmark]

36 minutes ago, anthonymm said:

I have to say, if you're a snow hater in sne or the mid atlantic it's been an amazing string of years! Pattern looks to continue.

I'm not sure how you interpret my compsites in that manner. It's not a KU cookbook, no....ah, you live in Jersey, so maybe.

[jm1220]

5 hours ago, 40/70 Benchmark said:

There are some posters you just know are never going to deliver good news, and if they ever do, it will be measured and delivered with ample caveats. Seem them post....brace first, read later-

When there’s ever a good outcome for my latitude east of the Apps again I’ll go with what you’re saying. I hate the bad news as much as anyone but there’s solid reasoning behind it and little evidence it’s changing soon.