2025-2026 ENSO

[snowman19]

The EURO seasonal is showing classic La Niña/-IOD low frequency forcing over the eastern IO and Maritime Continent for OND:

[donsutherland1]

3 hours ago, snowman19 said:

The EURO seasonal is showing classic La Niña/-IOD low frequency forcing over the eastern IO and Maritime Continent for OND:
 

The IOD has been declining in recent months and has already turned negative. It seems that things are on track for the forecast.

[bluewave]

Yeah, the record SST warmth near the Maritime Continent has been leading to significantly more -IODs over time than we used to get.

 

[mitchnick]

Sst changes in the western Pacific starting to raise the PDO some again.

[snowman19]

Sst changes in the western Pacific starting to raise the PDO some again.

Tropical cyclones passing through the area

[mitchnick]

Just now, snowman19 said:

Tropical cyclones passing through the area

Yeah, that's what's been missing for a while.

[GaWx]

27 minutes ago, mitchnick said:

Sst changes in the western Pacific starting to raise the PDO some again.

That means the equivalent daily NOAA PDO has risen from ~-4.25 to near -3.

[snowman19]

39 minutes ago, GaWx said:

That means the equivalent daily NOAA PDO has risen from ~-4.25 to near -3.

If the tropical cyclone activity stops, those waters/SSTs off Japan are going to warm right back up again quickly. Those extremely warm waters go to depth, they aren’t just at the surface. @Bluewave showed the subsurface anomaly cross-section back in the spring I believe, they go to depth

[FPizz]

19 minutes ago, snowman19 said:

If the tropical cyclone activity stops, those waters/SSTs off Japan are going to warm right back up again quickly. Those extremely warm waters go to depth, they aren’t just at the surface. @Bluewave showed the subsurface anomaly cross-section back in the spring I believe, they go to depth

Ever since Fukushima its been warm, odd.  Just kidding.  

[mitchnick]

2 hours ago, snowman19 said:

If the tropical cyclone activity stops, those waters/SSTs off Japan are going to warm right back up again quickly. Those extremely warm waters go to depth, they aren’t just at the surface. @Bluewave showed the subsurface anomaly cross-section back in the spring I believe, they go to depth

There's no guarantee of that.  That's pure wishcasting on your part. There's a whole lot that goes into ssta. 

[so_whats_happening]

2 hours ago, mitchnick said:

There's no guarantee of that.  That's pure wishcasting on your part. There's a whole lot that goes into ssta. 

I mean there is a lot of warmth with depth that has yet to be mixed. We do need much more in the way of tropical/ synoptic activity to really overhaul this region which will take time. There is definitely a noticeable shift trying to take place but the pattern is still very much entrenched across the region. As much as I want it to change it still needs time to make these changes.

[snowman19]

9 hours ago, mitchnick said:

There's no guarantee of that.  That's pure wishcasting on your part. There's a whole lot that goes into ssta. 

No it’s not. If you actually knew what you were talking about you’d realize that. The wishcasting is on your part

[snowman19]

@DonSutherland1 Looks like the anticipated shift to a -AAM regime has just started

[mitchnick]

5 hours ago, snowman19 said:

No it’s not. If you actually knew what you were talking about you’d realize that. The wishcasting is on your part

I didn't make a forecast like you did. Lol You always speak in absolutes. That's the problem. 

[mitchnick]

6 hours ago, so_whats_happening said:

I mean there is a lot of warmth with depth that has yet to be mixed. We do need much more in the way of tropical/ synoptic activity to really overhaul this region which will take time. There is definitely a noticeable shift trying to take place but the pattern is still very much entrenched across the region. As much as I want it to change it still needs time to make these changes.

I agreed the tropical activity was likely the cause. But to say with absolute certainty something will happen is what I question. And at what level of tropical activity is the tipping point? And what about the changing patterns? That's my point...it's not black or white.

[40/70 Benchmark]

14 hours ago, GaWx said:

That means the equivalent daily NOAA PDO has risen from ~-4.25 to near -3.

Everything that I am looking at says an extreme/ record PDO at this time of year is gong to elevate percipitously as we head into winter, which isn't a shock...one direction in which to go. Obviously it will be negative this winter.

[40/70 Benchmark]

13 hours ago, snowman19 said:

If the tropical cyclone activity stops, those waters/SSTs off Japan are going to warm right back up again quickly. Those extremely warm waters go to depth, they aren’t just at the surface. @Bluewave showed the subsurface anomaly cross-section back in the spring I believe, they go to depth

I will confidnetly bet against the PDO returning to those levels during the upcoming cold season.

[snowman19]

1 hour ago, 40/70 Benchmark said:

I will confidnetly bet against the PDO returning to those levels during the upcoming cold season.

No one here said it will maintain severely negative levels. But is a solidly -PDO winter a very good bet? Absolutely 

[40/70 Benchmark]

5 minutes ago, snowman19 said:

No one here said it will maintain severely negative levels. But is a solidly -PDO winter a very good bet? Absolutely 

Yes.

[bluewave]

1 hour ago, 40/70 Benchmark said:

I will confidnetly bet against the PDO returning to those levels during the upcoming cold season.

I think what we have been seeing from that record warm pool east of Japan in the 2020s is a seasonal shift from the summer into the fall and winter. The SST anomalies have been peaking there during the summers. Then declining as we have moved into the winter.

Notice how the -PDO readings have also been following this pattern. The summer into fall 2021, 2022, and 2024 displayed a similar process. The lowest -PDO readings have occurred in the summer and fall and have risen into the winter. So the 21-22, 22-23, and 24-25 winters were all rising PDO patterns off the strongly negative values of the summer and fall.

The main theme is that this seasonal pattern has kept repeating. So the winter values can’t get high enough to reverse the PDO when it starts declining again into the summers.  

The SSTs are marker for the 500mb ridging which keeps returning to the same areas. So even when we had a weaker trough east of Japan last winter, the SSTs couldn’t fully cool down. This could be related to the deep subsurface warmth there. Then there could be a feedback process between the atmosphere and SSTs perpetuating the 500mb pattern and extended record SSTs and -PDOs.

[snowman19]

7 minutes ago, bluewave said:

I think what we have been seeing from that record warm pool east of Japan in the 2020s is a seasonal shift from the summer into the fall and winter. The SST anomalies have been peaking there during the summers. Then declining as we have moved into the winter.

Notice how the -PDO readings have also been following this pattern. The summer into fall 2021, 2022, and 2024 displayed a similar process. The lowest -PDO readings have occurred in the summer and fall and have risen into the winter. So the 21-22, 22-23, and 24-25 winters were all rising PDO patterns off the strongly negative values of the summer and fall.

The main theme is that this seasonal pattern has kept repeating. So the winter values can’t get high enough to reverse the PDO when it starts declining again into the summers.  

The SSTs are marker for the 500mb ridging which keeps returning to the same areas. So even when we had a weaker trough east of Japan last winter, the SSTs couldn’t fully cool down. This could be related to the deep subsurface warmth there. Then there could be a feedback process between the atmosphere and SSTs perpetuating the 500mb pattern and extended record SSTs and -PDOs.

There has also been a propensity for -PMM the last several winters and thus a weak to very weak STJ….

[40/70 Benchmark]

10 minutes ago, bluewave said:

I think what we have been seeing from that record warm pool east of Japan in the 2020s is a seasonal shift from the summer into the fall and winter. The SST anomalies have been peaking there during the summers. Then declining as we have moved into the winter.

Notice how the -PDO readings have also been following this pattern. The summer into fall 2021, 2022, and 2024 displayed a similar process. The lowest -PDO readings have occurred in the summer and fall and have risen into the winter. So the 21-22, 22-23, and 24-25 winters were all rising PDO patterns off the strongly negative values of the summer and fall.

The main theme is that this seasonal pattern has kept repeating. So the winter values can’t get high enough to reverse the PDO when it starts declining again into the summers.  

The SSTs are marker for the 500mb ridging which keeps returning to the same areas. So even when we had a weaker trough east of Japan last winter, the SSTs couldn’t fully cool down. This could be related to the deep subsurface warmth there. Then there could be a feedback process between the atmosphere and SSTs perpetuating the 500mb pattern and extended record SSTs and -PDOs.

Yes, I'm not necessarily arguing for a wholescale pattern change....just a rising PDO that will be somewhat less negative.

[bluewave]

32 minutes ago, 40/70 Benchmark said:

Yes, I'm not necessarily arguing for a wholescale pattern change....just a rising PDO that will be somewhat less negative.

Yeah, this has been the theme during this decade with the PDO values rising into the winter and spring.

https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat

Oct 2021….-3.13……..Mar 2022….-1.67

Jul 2022....-2.64…….Jan 2023…..-1.24

Sep 2023…-2.99…….Feb 2024…..-1.33

Oct 2024…..-3.80……Mar 2025…..-1.15

[40/70 Benchmark]

36 minutes ago, bluewave said:

Yeah, this has been the theme during this decade with the PDO values rising into the winter and spring.

https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat

Oct 2021….-3.13……..Mar 2022….-1.67

Jul 2022....-2.64…….Jan 2023…..-1.24

Sep 2023…-2.99…….Feb 2024…..-1.33

Oct 2024…..-3.80……Mar 2025…..-1.15

Yes, this is what I was referring to.

[George001]

7 hours ago, snowman19 said:

No one here said it will maintain severely negative levels. But is a solidly -PDO winter a very good bet? Absolutely 

Agreed, I would bet on a moderate to strong -PDO winter, similar to last year. The question is what does this actually mean? Cold ENSO -PDO combo is a mixed bag, it’s the warm ENSO/-PDO combo that is a death sentence for east coast snow prospects. Jan 22 had a -2.4 PDO….. and so did December 11. Some winters are clear cut going in like 23-24 and 14-15, I don’t think this going to be one of those.

Speaking of 14-15, things look WAY different than they did in the summer of 14. Good call on the skepticism of the 13-14 analog last year, it was a cold winter but was also dry. I remember you brought up the fall conditions being completely different than fall of 13 as a counterargument when I and some others argued that 13-14 was a great analog. It had value, but it definitely wasn’t as good of an analog as I thought.  For this year given the information we currently have I’m looking at last year, 11-12, 21-22, 08-09, 13-14, 01-02, 12-13 as early analogs. What are your early thoughts for analogs?

 

[so_whats_happening]

16 hours ago, mitchnick said:

I agreed the tropical activity was likely the cause. But to say with absolute certainty something will happen is what I question. And at what level of tropical activity is the tipping point? And what about the changing patterns? That's my point...it's not black or white.

It is the same issue I had with folks thinking there were not 2013/14 style patterns showing up last season but since it did not snow nearly as much last year it was not a match. Not everything is exact and unfortunately you will not change the minds of folks, it is what it is. 

To redistribute that amount of warming you likely need consistent typhoon recurves and at that strong consistent synoptic activity coming off China/ Koreas/ Japan. Tropical activity has been very sluggish in the WPAC for some time and when we do have activity the main track has been almost due west at low latitudes with the stronger systems (maybe 1 or 2 systems in a season actually recurving) or 'home grown' systems (close to land formation).

Honestly let's just see how it all plays out.

[snowman19]

Agreed, I would bet on a moderate to strong -PDO winter, similar to last year. The question is what does this actually mean? Cold ENSO -PDO combo is a mixed bag, it’s the warm ENSO/-PDO combo that is a death sentence for east coast snow prospects. Jan 22 had a -2.4 PDO….. and so did December 11. Some winters are clear cut going in like 23-24 and 14-15, I don’t think this going to be one of those.
Speaking of 14-15, things look WAY different than they did in the summer of 14. Good call on the skepticism of the 13-14 analog last year, it was a cold winter but was also dry. I remember you brought up the fall conditions being completely different than fall of 13 as a counterargument when I and some others argued that 13-14 was a great analog. It had value, but it definitely wasn’t as good of an analog as I thought.  For this year given the information we currently have I’m looking at last year, 11-12, 21-22, 08-09, 13-14, 01-02, 12-13 as early analogs. What are your early thoughts for analogs?
 

Unless there is a very radical shift in the PDO to a Victoria mode between now and December, I would not have 13-14 as an analog. The blooming -IOD also doesn’t fit, neither does ENSO

[40/70 Benchmark]

22 minutes ago, snowman19 said:

Unless there is a very radical shift in the PDO to a Victoria mode between now and December, I would not have 13-14 as an analog. The blooming -IOD also doesn’t fit, neither does ENSO

I don't necessarily agree with this. Its a good polar and ENSO analog.

[bluewave]

On 8/12/2025 at 6:08 PM, snowman19 said:

If the tropical cyclone activity stops, those waters/SSTs off Japan are going to warm right back up again quickly. Those extremely warm waters go to depth, they aren’t just at the surface. @Bluewave showed the subsurface anomaly cross-section back in the spring I believe, they go to depth

Yeah, remarkable subsurface warmth well beyond anything that we have seen before. So these record low -PDO values are just scratching the surface. We saw how quickly the SSTs rebounded after last winter. So this new dynamic helps this pattern to really persist. 

[snowman19]

30 minutes ago, 40/70 Benchmark said:

I don't necessarily agree with this. Its a good polar and ENSO analog.

IMO we are more “Niña” than 13-14 was