2025-2026 ENSO

[40/70 Benchmark]

27 minutes ago, snowman19 said:

IMO we are more “Niña” than 13-14 was

Negligible. I seem to recall you questioning whether there was a discernible difference between ENSO neutral and weak La Nina when people were questioning whether this would become an official La Nina....is that particular take context dependent?

[40/70 Benchmark]

2014 peaked at .52 RONI. I don't see it getting below -1.0 this season. MEI peaked at -0.5....They haven't updated since AM, but I can't imagine that is going to get much lower than the RONI. 

[snowman19]

Negligible. I seem to recall you questioning whether there was a discernible difference between ENSO neutral and weak La Nina when people were questioning whether this would become an official La Nina....is that particular take context dependent?

It is negligible yes, but if I’m not mistaken, the MEI is deeper into Niña mode this year

[PhiEaglesfan712]

2 minutes ago, snowman19 said:

It is negligible yes, but if I’m not mistaken, the MEI is deeper into Niña mode this year

Not really, the MEI peaked at -1.14 in the offseason of 2012-13 and 2013-14. It does seem pretty odd, though, since the RONI and ONI both were in the -0.4 range during that time, and neither season produced a la nina on the MEI.

[40/70 Benchmark]

12 minutes ago, snowman19 said:

It is negligible yes, but if I’m not mistaken, the MEI is deeper into Niña mode this year

Don't get me wrong....I try to be pretty objective and back you up on plenty of takes, but you seem to be reaching here to eliminate that season from consideration altogether. The MEI hasn't been update since May, so perhaps you are mistaken. The RONI is -.40 and rising....

[snowman19]

1 minute ago, 40/70 Benchmark said:

Don't get me wrong....I try to be pretty objective and back you up on plenty of takes, but you seem to be reaching here to eliminate that season from consideration altogether. The MEI hasn't been update since May, so perhaps you are mistaken. The RONI is -.40 and rising....

My main reason is the PDO which can obviously change between now and December. Maybe I should have been clearer, not a total elimination, but it would be the very last on my analog list as of now

[40/70 Benchmark]

5 minutes ago, snowman19 said:

My main reason is the PDO which can obviously change between now and December. Maybe I should have been clearer, not a total elimination, but it would be the very last on my analog list as of now

Yea, the PDO and PNA part ways relatively frequently, as was the case last season. This is probably why the PNA in many of my analogs isn't as negative as you seem to think.

[bluewave]

23 minutes ago, 40/70 Benchmark said:

Yea, the PDO and PNA part ways relatively frequently, as was the case last season. This is probably why the PNA in many of my analogs isn't as negative as you seem to think.

There has been a new relationship between the -PDO and PNA especially during the 2020s summers. This was our first July streak of 5 consecutive -2 to -4 -PDOs. There has been a very strong +PNA signal leading to the record wildfires, record heat, and drought up in Canada.

Past instances of -2 -PDOs in July were more -PNA. My guess is that this is related to the -PDO being more driven by the warmer SST anomalies than the colder ones which used to dominate -PDOs in the past. 
 

Recent July -2 to -4 -PDOs have been more +PNA

 

Older -PDO below -2 in July were more -PNA

 

[snowman19]

51 minutes ago, 40/70 Benchmark said:

Yea, the PDO and PNA part ways relatively frequently, as was the case last season. This is probably why the PNA in many of my analogs isn't as negative as you seem to think.

My guess is that the PNA is more negative during the winter than last year….2nd year -ENSO

[40/70 Benchmark]

58 minutes ago, snowman19 said:

My guess is that the PNA is more negative during the winter than last year….2nd year -ENSO

And I agree, as it was strongly positive last year, but I don't think it will be strongly negative this season.

[Terpeast]

1 hour ago, bluewave said:

There has been a new relationship between the -PDO and PNA especially during the 2020s summers. This was our first July streak of 5 consecutive -2 to -4 -PDOs. There has been a very strong +PNA signal leading to the record wildfires, record heat, and drought up in Canada.

Past instances of -2 -PDOs in July were more -PNA. My guess is that this is related to the -PDO being more driven by the warmer SST anomalies than the colder ones which used to dominate -PDOs in the past. 
 

Recent July -2 to -4 -PDOs have been more +PNA

 

Older -PDO below -2 in July were more -PNA

 

I think I see why. Looking at the upper left of each plot, the jet is further north in the new vs old. So instead of buckling southward into western US, it goes over the top of NW Canada promoting a ridge there. Big changes downstream. 

[40/70 Benchmark]

1 hour ago, bluewave said:

There has been a new relationship between the -PDO and PNA especially during the 2020s summers. This was our first July streak of 5 consecutive -2 to -4 -PDOs. There has been a very strong +PNA signal leading to the record wildfires, record heat, and drought up in Canada.

Past instances of -2 -PDOs in July were more -PNA. My guess is that this is related to the -PDO being more driven by the warmer SST anomalies than the colder ones which used to dominate -PDOs in the past. 
 

Recent July -2 to -4 -PDOs have been more +PNA

 

Older -PDO below -2 in July were more -PNA

 

 

1 hour ago, snowman19 said:

My guess is that the PNA is more negative during the winter than last year….2nd year -ENSO

 

6 minutes ago, 40/70 Benchmark said:

And I agree, as it was strongly positive last year, but I don't think it will be strongly negative this season.

 

[40/70 Benchmark]

This doesn't mean you should book 70" of snowfall at LGA.....but it is what it is. The PNA should be just south of neutral in the DM mean.

[bluewave]

1 hour ago, snowman19 said:

My guess is that the PNA is more negative during the winter than last year….2nd year -ENSO

Yeah, that is my early guess based on past multiyear La Ninas since the late 90s.

There is usually one year with a strong +PNA December mismatch. The other surrounding Decembers had either a weaker positive or a negative PNA.

So I will go lower on the PNA for December 2025 than the +1.70 we had in December 2024. But not sure yet whether it’s just a weaker positive or the PNA dips negative. 
 

Multiyear La Ninas and December PNA

2025…….?

2024….+1.70

 

2022….-0.66

2021….-2.56

2020…+1.58

2017…..+0.89

2016….-0.35

 

2011….+0.36

2010….-1.78

 

2008….-1.41

2007…..+0.14

 

2000…..+1.23

1999…..+0.21

1998…..-0.09