2024-2025 La Nina

[Maestrobjwa]

1 minute ago, 40/70 Benchmark said:

Most of the periods of disconnect from the west Pac warm pool driven MC forcing has actually been in January into early February. 

That warm pool still there like it has been seemingly forever? (And I never have quite understood what it is exactly)

[Stormchaserchuck1]

It looks like the CPC thinks the EPO will go negative for the Winter, or the N. Pacific ridge will go polar and extend north. I had this opinion in the Summer, but the last 1-2 months has been more of the same pattern that we have seen for the last 6 Winter's, imo. Will be interesting to see if they verify.. they usually don't go so cold as they are over the PNW and Upper Midwest for a 3-month period. This is especially interesting because the SW, US has been +7F over their all time records for a 3-week period lately. They usually smooth the overall warming signal out for a seasonal forecast, but the forecast is downright cold in the NW 1/3 of the US. 

If the NW has such a cold Winter, I don't see how we don't go extremely warm in the East, given what has happened over the last few Winters.. we had 3 days of +NAO ridging last January, and DC hit 80*. The same is happening tomorrow.. the NAO is going positive, and there is a 591dm ridge over Toronto, Canada. Little spikes are causing some extreme +departures days. 

[so_whats_happening]

3 hours ago, bluewave said:

The ridges across the North Pacific and North Atlantic have been linking up into one continuous ridge during 4 out of the last 5 summers. So it’s no surprise the SSTs have been reaching record levels outside the traditional -PDO zones with so much subsidence and sunshine. The warm pool off of California and the strong ridge is a new feature which wasn’t there during the older -PDO era. Notice how there has been a continuous ridge and record SSTs underneath across much of the North Pacific. Same goes for the North Atlantic. The last strong -PDO in the early 1950s was defined more by the giant NP cold pool. These days it’s a record warm pool driving the -PDO. Also notice how the ridges back there were much weaker and covered a smaller area compared to the recent summers.

 

 

I mean just looking at the SST patterns they look very similar in both time periods, right now we have warmer oceans so to compensate for the same -PDO signature and value we have higher anomalies than the surroundings just as you did back in the day. As for the 500mb pattern can't explain the difference but we could easily be in a constructive pattern versus a destructive pattern overall. Im sure the atmospheric warmth right now plays a role in allowing a more ridge like presence versus a trough like presence but im sure this flip flops so much it is hard to say this will be what the pattern should be.

The biggest issue I have is we have seen these marine heatwaves before this is in fact what you are pointing out right now but what is to say that a -PDO should produce this atmospheric pattern. It may be more common for a pattern to occur during these strong phases of teleconnection but it does not necessarily mean that this will always be the resulting pattern.

Im sure ill get lambasted for such a take.

[michsnowfreak]

1 hour ago, Stormchaserchuck1 said:

It looks like the CPC thinks the EPO will go negative for the Winter, or the N. Pacific ridge will go polar and extend north. I had this opinion in the Summer, but the last 1-2 months has been more of the same pattern that we have seen for the last 6 Winter's, imo. Will be interesting to see if they verify.. they usually don't go so cold as they are over the PNW and Upper Midwest for a 3-month period. This is especially interesting because the SW, US has been +7F over their all time records for a 3-week period lately. They usually smooth the overall warming signal out for a seasonal forecast, but the forecast is downright cold in the NW 1/3 of the US. 

If the NW has such a cold Winter, I don't see how we don't go extremely warm in the East, given what has happened over the last few Winters.. we had 3 days of +NAO ridging last January, and DC hit 80*. The same is happening tomorrow.. the NAO is going positive, and there is a 591dm ridge over Toronto, Canada. Little spikes are causing some extreme +departures days. 

Are you still liking above avg precip in the Lakes?

[Stormchaserchuck1]

1 hour ago, michsnowfreak said:

Are you still liking above avg precip in the Lakes?

Yeah. Possibly well above average, as the normal jet stream is south in the Winter, but a SE ridge would have storms riding up to the Great Lakes. 

You could be pretty excited by the CPC's Winter forecast, with cold dropping in not too far away, but I'm not really agreeing with them. I think they are really underestimating the potential warmth in the east, only giving 40-50% chance for above normal here.  I think this Winter will have a lot of variation/volatility.. I think we may see -WPO/-EPO periods, but they may not last more than 5-8 days. The overall trend will be warm. It's a little bit different when a Winter is wall-to-wall warm, vs very warm periods and below average periods.. You can get snow in Winter's of variance.. I had a 20" storm in 99-00. If we have a +NAO jet stream like I think, the timing with a -EPO period could give you a nice snowstorm(s).  It's not all ridgy everywhere like the last few years, so northern areas should do ok I think. 

[snowman19]

The ridges across the North Pacific and North Atlantic have been linking up into one continuous ridge during 4 out of the last 5 summers. So it’s no surprise the SSTs have been reaching record levels outside the traditional -PDO zones with so much subsidence and sunshine. The warm pool off of California and the strong ridge is a new feature which wasn’t there during the older -PDO era. Notice how there has been a continuous ridge and record SSTs underneath across much of the North Pacific. Same goes for the North Atlantic. The last strong -PDO in the early 1950s was defined more by the giant NP cold pool. These days it’s a record warm pool driving the -PDO. Also notice how the ridges back there were much weaker and covered a smaller area compared to the recent summers.
 





 

Very good model consensus now (GEFS EPS GEPS) for the beginning of November

[40/70 Benchmark]

14 hours ago, Stormchaserchuck1 said:

It's one thing when the PDO is X value. It's another when it's accurately predicting the state of the atmosphere months in advance.  In 2013 it was not hitting in the Fall. 

The one month that the PDO doesn't have a high correlation to is December.. 

Its highest is Jan-Feb. SE ridge signal of +0.5, or 75%. 

March is just as weak as December. 

My guess is that correlation is greater now than it was 60 years ago. The polar domain seems to have had a greater capacity to counter a hostile Pacific back then.

[bluewave]

12 hours ago, so_whats_happening said:

I mean just looking at the SST patterns they look very similar in both time periods, right now we have warmer oceans so to compensate for the same -PDO signature and value we have higher anomalies than the surroundings just as you did back in the day. As for the 500mb pattern can't explain the difference but we could easily be in a constructive pattern versus a destructive pattern overall. Im sure the atmospheric warmth right now plays a role in allowing a more ridge like presence versus a trough like presence but im sure this flip flops so much it is hard to say this will be what the pattern should be.

The biggest issue I have is we have seen these marine heatwaves before this is in fact what you are pointing out right now but what is to say that a -PDO should produce this atmospheric pattern. It may be more common for a pattern to occur during these strong phases of teleconnection but it does not necessarily mean that this will always be the resulting pattern.

Im sure I’ll get lambasted for such a take.

It’s new Pacific pattern outlined in this recent paper. This is why trying to compare this -PDO the pre 2015 Pacific hasn’t been working out. So we get this new persistent pattern with record marine heatwaves and Aleutian ridging.

 

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022GL101078

Remarkable Changes in the Dominant Modes of North Pacific Sea Surface Temperature

The analysis revisits the calculation of the empirical orthogonal functions (EOFs) and principal components (PCs) of sea surface temperature (SST) in the North Pacific from 1950 to 2021. The first EOF and PC of SST has proven to be such a useful metric of variability in the North Pacific that it is called the Pacific Decadal Oscillation (PDO). We find that the period of persistent marine heatwaves beginning in 2014 caused a fundamental change to the first EOF and PC of SST (calculated using data from 1950 to 2021) as compared to the established PDO spatial pattern (calculated using data from 1950 to 1993). The second EOF of SST has also changed during this period, both in spatial pattern and in the amount of variance explained. A conclusion is that the PDO and other EOF based metrics may not be as useful in the future as climate continues to change.

Key Points

 

• The calculation of empirical orthogonal functions and principal components of North Pacific sea surface temperature is revisited

• The period of persistent marine heatwaves since 2014 has caused most energetic modes to change

• A conclusion is that indices based on empirical orthogonal function analysis may not be as useful as climate continues to change

 

Plain Language Summary

The Pacific Decadal Oscillation (PDO) is a widely used measure of the temperature variability in the North Pacific Ocean. The PDO is the result of a well-known technique called empirical orthogonal function (EOF) analysis that isolates the most energetic modes of variability of the analyzed variable. The first time EOF analysis was applied to oceanographic data was in the 1970's when it was used to identify the most energetic modes of North Pacific sea surface temperature (SST). The first EOF of North Pacific SST has proved so useful as a measure that it received the moniker PDO. Our analysis suggests that a period of persistent marine heatwaves in the North Pacific since 2014 has been so powerful that this first mode of variability of SST has fundamentally changed and the PDO may not be as useful an indicator as it once was.

 

[mitchnick]

Notwithstanding the recent trades, as of 10/16, Oisst SSTA for ENSO 1+2, 3, 3.4 and 4 respectively are only: -0.077; +0.058; -0.138 & +0.031.

Those are solid La Nada numbers.

https://cyclonicwx.com/sst.php

[purduewx80]

And yet the updated RONI moved deeper into Niña territory. Still not seeing AS numbers for the MEIv2. 

[jm1220]

11 hours ago, Stormchaserchuck1 said:

Yeah. Possibly well above average, as the normal jet stream is south in the Winter, but a SE ridge would have storms riding up to the Great Lakes. 

You could be pretty excited by the CPC's Winter forecast, with cold dropping in not too far away, but I'm not really agreeing with them. I think they are really underestimating the potential warmth in the east, only giving 40-50% chance for above normal here.  I think this Winter will have a lot of variation/volatility.. I think we may see -WPO/-EPO periods, but they may not last more than 5-8 days. The overall trend will be warm. It's a little bit different when a Winter is wall-to-wall warm, vs very warm periods and below average periods.. You can get snow in Winter's of variance.. I had a 20" storm in 99-00. If we have a +NAO jet stream like I think, the timing with a -EPO period could give you a nice snowstorm(s).  It's not all ridgy everywhere like the last few years, so northern areas should do ok I think. 

In any Nina I’d be excited if I lived in the Great Lakes. Doesn’t score there 100% of the time but odds are certainly better given the Lake cutter storm tracks. 

[snowman19]

1 hour ago, purduewx80 said:

And yet the updated RONI moved deeper into Niña territory. Still not seeing AS numbers for the MEIv2. 

Not surprising given the very strong Niña background state 

[40/70 Benchmark]

6 minutes ago, snowman19 said:

Not surprising given the very strong Niña background state 

Its running comfortably behind 2022....but I'm not sure that matters all that much because the implication of this is that the hemisphere will be more prone to extratropical drivers vs ENSO, the most prominent of which continues to be the W PAC Warm pool.

Remember...weaker doesn't mean "cold".....it just works out that way because the extra tropical drivers usually involve more cold than an ENSO predominate forcing regime would. However, in this case that isn't true. This is probably why @bluewavehas found that weaker La Nina hasn't bee helpful like it has in the past.

[40/70 Benchmark]

This is why some weaker El Nino events such as 2006 and some of the ones from the 50s were still warm....the extra tropical Pacific. Toned down versions of last year.

[Typhoon Tip]

2 hours ago, bluewave said:

It’s new Pacific pattern outlined in this recent paper. This is why trying to compare this -PDO the pre 2015 Pacific hasn’t been working out. So we get this new persistent pattern with record marine heatwaves and Aleutian ridging.

 

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022GL101078

Remarkable Changes in the Dominant Modes of North Pacific Sea Surface Temperature

The analysis revisits the calculation of the empirical orthogonal functions (EOFs) and principal components (PCs) of sea surface temperature (SST) in the North Pacific from 1950 to 2021. The first EOF and PC of SST has proven to be such a useful metric of variability in the North Pacific that it is called the Pacific Decadal Oscillation (PDO). We find that the period of persistent marine heatwaves beginning in 2014 caused a fundamental change to the first EOF and PC of SST (calculated using data from 1950 to 2021) as compared to the established PDO spatial pattern (calculated using data from 1950 to 1993). The second EOF of SST has also changed during this period, both in spatial pattern and in the amount of variance explained. A conclusion is that the PDO and other EOF based metrics may not be as useful in the future as climate continues to change.

Key Points

 

• The calculation of empirical orthogonal functions and principal components of North Pacific sea surface temperature is revisited

• The period of persistent marine heatwaves since 2014 has caused most energetic modes to change

• A conclusion is that indices based on empirical orthogonal function analysis may not be as useful as climate continues to change

 

Plain Language Summary

The Pacific Decadal Oscillation (PDO) is a widely used measure of the temperature variability in the North Pacific Ocean. The PDO is the result of a well-known technique called empirical orthogonal function (EOF) analysis that isolates the most energetic modes of variability of the analyzed variable. The first time EOF analysis was applied to oceanographic data was in the 1970's when it was used to identify the most energetic modes of North Pacific sea surface temperature (SST). The first EOF of North Pacific SST has proved so useful as a measure that it received the moniker PDO. Our analysis suggests that a period of persistent marine heatwaves in the North Pacific since 2014 has been so powerful that this first mode of variability of SST has fundamentally changed and the PDO may not be as useful an indicator as it once was.

 

this reminds me of a personal muse i've been struggling with .. and that has to do with identifying the pacific warming as a heat "wave"  

waves by definition have a time dependency where they do not persist indefinitely.    it's a wave ... it has some sort of precursor physical registry in the system, followed by a surge in whatever metric it is effecting, followed by a reduction in energy.   thus, it is an ephemeral condition.  

it may just be a matter of semantic nitty picky shit ... or, maybe it reflects a fallacy in the understanding of what is going on with the oceanic sst/energy budget overall, within the ocean and outside where it is quasi coupled to the troposphere.   hmmm like maybe this is not a 'wave' in that sense and should be thought of us the new basal state.

in which case ...yeah, any telecon correlations that were previous to the new mode are rendered less than correlative.  

this true all over and everywhere.   teleconnectors are correlating oddly.  get use to it because the world may not be going back

[40/70 Benchmark]

@bluewaveDo you have those graphics that you used to show how last season's extreme warmth was a blend of unfavorable cool ENSO and warm ENSO elements?

[George001]

Siberian snow cover is advancing rapidly, the quickest pace since October 2014. According to Cohens research, rapid advance of the Siberian snow cover is linked to -AO pattern during winter and a weaker polar vortex. It is especially interesting that this is happening in a year with a fairly strong +NAO and +AO signal (high solar, high geomag, etc).

[snowman19]

14 minutes ago, George001 said:

Siberian snow cover is advancing rapidly, the quickest pace since October 2014. According to Cohens research, rapid advance of the Siberian snow cover is linked to -AO pattern during winter and a weaker polar vortex. It is especially interesting that this is happening in a year with a fairly strong +NAO and +AO signal (high solar, high geomag, etc).

Voodoo IMO

[40/70 Benchmark]

22 minutes ago, George001 said:

Siberian snow cover is advancing rapidly, the quickest pace since October 2014. According to Cohens research, rapid advance of the Siberian snow cover is linked to -AO pattern during winter and a weaker polar vortex. It is especially interesting that this is happening in a year with a fairly strong +NAO and +AO signal (high solar, high geomag, etc).

He just posted last week that it looked like crap after a promising start.

[40/70 Benchmark]

8 minutes ago, snowman19 said:

Voodoo IMO

Well, you made sure to post his tweet when he said it didn't look good.

[mitchnick]

4 minutes ago, 40/70 Benchmark said:

He just posted last week that it looked like crap after a promising start.

Twitter?

[snowman19]

6 minutes ago, 40/70 Benchmark said:

Well, you made sure to post his tweet when he said it didn't look good.

Because I knew what was coming next to prove a point…he always does. Doom and gloom then bliss. Dr. Jeckyll and Mr. Hyde. As predictable as the rising sun. I started thinking the SAI was BS back during the 15-16 super El Niño. He was going for an arctic cold winter for the east because Siberian snowcover build up was very high. The hype was off the charts even as region 3.4 hit +3.1C at the end of November. Then winter happened and that wasn’t the only example over the last 15 years….

[40/70 Benchmark]

3 minutes ago, snowman19 said:

Because I knew what was coming next to prove a point…he always does. Doom and gloom then bliss. Dr. Jeckyll and Mr. Hyde. As predictable as the rising sun. I started thinking the SAI was BS back during the 15-16 super El Niño. He was going for an arctic cold winter for the east because Siberian snowcover build up was very high. The hype was off the charts even as region 3.4 hit +3.1C at the end of November. Then winter happened and that wasn’t the only example over the last 15 years….

I'm not debating your point, but I will say that I do think it offers some utility. I certainly wouldn't base an entire outlook off of it....I use it to either bolster confidence or to introduce an alternate perspective.

[40/70 Benchmark]

6 minutes ago, mitchnick said:

Twitter?

Yea.

[FPizz]

4 minutes ago, mitchnick said:

Twitter?

Yes.  His tweet 3 days ago showed it is the highest in 9 years. 

[brooklynwx99]

13 minutes ago, 40/70 Benchmark said:

Well, you made sure to post his tweet when he said it didn't look good.

did the same thing last year lmao

[snowman19]

1 minute ago, brooklynwx99 said:

did the same thing last year lmao

I live rent free in your head lol Must have my posts saved on a file on your home computer lol

[Cobalt]

7 minutes ago, snowman19 said:

I live rent free in your head lol Must have my posts saved on a file on your home computer lol

he's not wrong though? You certainly wouldn't have shared a Judah Cohen tweet touting a high snow cover ranking, 

[Eduardo]

10 minutes ago, 40/70 Benchmark said:

I'm not debating your point, but I will say that I do think it offers some utility. I certainly wouldn't base an entire outlook off of it....I use it to either bolster confidence or to introduce an alternate perspective.

Can you explain this (when you have time)?  I’ve always been a skeptic myself—more so in recent years, obviously.

[George001]

Just now, snowman19 said:

Voodoo IMO

To an extent yes, but I don’t think it’s completely meaningless. In my opinion it was overrated in the mid 2010s when some were considering it to be a silver bullet to winter forecasting where more Siberian snow cover = colder and snowier winters in the east. It isn’t that simple, never is. The takeaway I’m getting from it is an increased risk of the polar vortex being displaced south rather than consolidated over the North Pole. Yet, there are conflicting signals. The high solar and high geomag supports a +NAO pattern with a stronger polar vortex. The reason this interests me is what other years with rapid Siberian snow cover advance did during high solar/geomag years in the polar region. In 14-15, we had the rare combination of a strong polar vortex that was also displaced south. Make no mistake, these were still +NAO winters so it didn’t exactly prove Cohens theory correct (rapid Siberian snow cover advance = weaker polar vortex and -NAO/-AO). 

The big takeaway for me is while this is not a reason to go all Joe Bastardi and forecast well BN temps in the east with 200% of normal snow up and down 1-95 (cannot just ignore what’s going on with the pacific. I have gotten burned doing that one too many times and won’t make the same mistake again) its still worth looking at. I wouldn’t take this as a reason to forecast a -NAO (especially given that previous examples of high Siberian snow cover advancement with high solar/geomag were still +NAO winters, some even strongly +NAO). I’m thinking more along the lines of an +NAO winter with the vortex displaced more south than usual (this happened in 07-08, 14-15, 13-14, 92-93, and 93-94). 

Now…. All of this may not matter if the Siberian snow cover advance slows down and finishes around average. The month is not over so that’s still very possible. Just a week ago the Siberian snow cover advance was running below normal.