EasternLI

Maybe the NH is starting to come around slowly. If we use the JMA composite for warm enso in August. We see this wave train from the Pacific through NA. Then looking over the AIFS-ensembles 12z run, here is a 5 day mean. There is a wave train visible in the Pacific through NA similar to the one shown on the composite.

I think you're both right. The SST PDO is a reflection of a propensity of the atmosphere to favor that state. Whether that is positive or negative. There are also far longer term oscillations known, such as the IPO. Which can have a period of 40-60 years. I personally believe the IPO explains the long term negative period we have witnessed. There are also short term (+PDO) events within a long term -IPO, and vice versa. Although they are shorter lived than they otherwise would be when they oppose the IPO. With the + or - phase dominant over that entire period depending on the IPO. We are currently in a negative phase. We have been since the late 1990's. For one reason or another, the atmosphere has been predisposed towards -PDO thanks to that. I actually think this explains quite well a year like 23-24(-IPO). Where you can get an el nino with a -PDO. Or on the flip side, a year like 95-96(+IPO). Where you can get a la nina with a +PDO. The EOF of a +IPO is posted below followed by a few studies. Pay extra attention to the second one, as it relates to the North Pacific. Powerful enso events have the potential to flip the Pacific. As the la nina following 97-98 is attributed to beginning this current negative IPO phase. So we're closing in on 30 years now. In this context, I find an inbound record breaking el nino all the more interesting. There's a shot at flipping the longer term Pacific to something more like the following EOF. Instead of the opposite, which we've become accustomed to. The record wildfires in Australia several years ago also may have acted to extend this negative period beyond what it otherwise would have been. By driving the triple dip la nina of the 2020's. In fact it's been postulated that had those fires not happened. 2015-16 likely would have begun the transition to +IPO. The influence of the Interdecadal Pacific Oscillation on Temperature and Precipitation over the Globe https://link.springer.com/article/10.1007/s00382-015-2500-x "Since 1920, there are two warm (1924–1944 and 1977–1998) and two cold (1945–1976 and 1999–present) IPO phases, whose change is associated with abrupt shifts in North Pacific sea level pressure (SLP) and contrasting anomaly patterns in T and P and atmospheric circulation over the eastern and western Pacific." Statistical relationships between the Interdecadal Pacific Oscillation and El Niño–Southern Oscillation https://link.springer.com/article/10.1007/s00382-023-07035-8 " While the spatial SST patterns that represent the IPO and ENSO are similar, the IPO is meridionally broader in the central to eastern Pacific, which may be caused by a lagged relationship with low-frequency SST variability in the equatorial Pacific. In addition, North Pacific SST anomalies of opposite sign to the tropical Pacific SST anomalies is a unique feature of the IPO that cannot be explained by decadal ENSO variability. This suggests a clear IPO and ENSO relationship, but also independence in some of the IPO’s characteristics." The role of interannual ENSO events in decadal timescale transitions of the Interdecadal Pacific Oscillation https://link.springer.com/article/10.1007/s00382-021-05784-y "A long pre-industrial control run with CESM1 is analyzed to show that there is a greater chance of ENSO activity to contribute to an IPO transition when off-equatorial western Pacific Ocean heat content reaches either a maximum (for El Niño to contribute to a transition to positive IPO) or minimum (for La Niña to contribute to a transition to negative IPO) as seen in observations." 2019-2020 Australian bushfire smoke, multi-year La Niña, and implications for the Interdecadal Pacific Oscillation (IPO) https://www.nature.com/articles/s41612-025-01204-8

The H300 PDO or upper air PDO index came in at -2.03 for July. The last time this index was positive at all was 2015-16. The last time it was +1 or greater was 1997-98. 2026 1 -1.61 2026 2 -1.58 2026 3 -1.73 2026 4 -1.70 2026 5 -1.93 2026 6 -2.05 2026 7 -2.03

Today's run shows it well too.

Yes. Much of that has to do with modeled tropical cyclone activity. Mainly Typhoon Dolphin and 94W in the near term. Other stuff is modeled beyond that too. TC's can play some games with those RMM charts sometimes rendering them misleading. I enjoy looking at the MJO a little more in depth when I am able to. Including satellite obs. Notice around the MC it's actually mostly clear. The underlying MJO signal is poised to make it's way across the west Pacific then interact with the el nino. Beginning to offer amplification as it continues working its way further east during week 2. Aiding a powerful WWB as a result. That's my take on it anyway.

That's quite impressive looking too! I'm not quite sure what to expect with this thing other than a powerhouse STJ. It's unprecedented in many ways. I'm having fun just monitoring it. Tons of interesting aspects. Really fascinating event.

Yes, and it's looking like a big one too as the MJO swings back through again.

This loop is impressive.

Ah, I see what happened now. Sorry for the confusion this morning. You probably thought I was referencing what bluewave was posting about. I was not. I was referencing what so_whats_happening had posted. About recurving typhoons. Which is why I quoted him. Was a coincidence I posted that right after BW did. I think I could have worded that a little better. Perhaps it was just too early.

I feel that it will too but think it's also important to point out that there is some resistance out there.

Well yeah, but that's a totally different animal from today. That's in sync with the PDO. This El nino is out of sync. That makes all the difference and I can try to make a post later as to why. I never had any problem with la nina's. Weak to moderate enso of either sign historically can treat me well locally. It's neutral or very strong events I'm not overly fond to see. Here's a picture from the blizzard this past winter. Ended up with 2 feet.

That is the PDO battle royale in a nutshell. As a -PDO plus +ENSO can yield a weaker Aleutian low than you would otherwise expect to see. Yet, PDO variability and transitions has links to the strength of the Aleutian low too. So it's fascinating watching a +enso of this caliber coming up against the deeply entrenched -PDO state. Since Aleutian low strength has ties to +enso strength also. Does one or the other win out? Or is it more of a blend between the two? I lean towards a record el nino taking an upper hand at some point. I feel like this event has some potential to flip us out of that long term -PDO state too or at least begin to. Who knows, but it's really interesting to watch.

Let's do a comparison as things stand currently wrt SST's. Here's this year followed by the other strong/super el nino's going back to 82-83. Below is this year currently, followed by the others in reverse chronological order. Obviously, the globe is getting warmer over time. Naturally, sst's would follow suit. Is anyone disputing that fact anymore? I don't really see anyone doing that but not the point of this post. One can clearly see things warming over time. I've been floating around on these boards for a very long time now. There used to be discussions from very wise mets in the enso threads of yore on how actual sst's should be viewed and pondered. Not only the anomalies. So I'm posting the actual sst's as comparison. Looking at it this way, 97-98 and 87-88 stick out to me a little more so than the others. Again, not because of the actual readings compared to each other. Rather, the positioning of the warm pool biased east.

I would also like to see a recurving typhoon or two as @so_whats_happening very astutely brought up. That's another thing I'm keeping my eye's on. I feel like we will, sooner or later. Unfortunately nothing much on the radar for that currently. There's only this dubious TC that forms on the heels of typhoon Dolphin. All models show this system too, this is the euro below. Some want to recurve it, some don't. If it did, I might think of it as a baby step. I'm thinking the autumn could bring better chances though.

Oh absolutely. And feel the same way about the Pacific timing, I agree.

Yeah noticed that too, near mid August is the target date to me for maybe something like that to start to show up. AI-ENS on board too and has been. Didn't really look like the standard EPS was as interested as that yesterday. Maybe that idea is starting to gain a little traction.

This area of very warm water pooling that I circled. There's something really curious about that. It's exactly in the region with suggested links to PDO transitions. With a super nino inbound that's fascinating.

Yeah, it's up up up and away with the AAM it sure seems. You can see what's been driving that so far too. The SH and the tropics. The tropics for obvious reasons. NH hasn't been involved. Feels like the PDO would have some kind of hand in something like that. The south pacific jet though has been impressive. It's also been slamming into the Andes mountains creating periods of +MT. Giving boosts to the AAM. A very slight relaxation after mid July, but the far right of the chart shows it's already firing up again. There was actually a decent -MT recently during that relaxation and AAM remained quite elevated anyway. Now it's climbing again and slated to continue for the same reasons as before. Wait until the NH starts getting more involved in addition to all of that. Models suggesting that could begin to occur as soon as mid August. Will be interesting to see if that timeframe gets delayed or not.

I think we'll see a pretty darn robust STJ, eventually. Remember there's some resistance in the pacific with the -PDO too. That's a battle royale there IMO but I think the sheer magnitude of this el nino overwhelms it. But it's going to take some time to do that. Aifs-ens would suggest we see it start to fire up a little bit towards mid Aug. Will be interesting to see if that's accurate and if it starts to ramp up more as we move towards autumn. If we see that, I'd feel more confident. As far as the QBO is concerned. That's an area of ongoing research. Which has been noticed more and more as an important factor in various areas. So it has been gaining more and more interest. Here's some newer work that also included the Pacific jet. The image below is actually a cross section of the jet in late winter. Same conclusion. El nino + WQBO is the combo for the strongest jet. ERA5 data in top row model runs in the rows underneath. QBOi El Niño–Southern Oscillation experiments: teleconnections of the QBO https://wcd.copernicus.org/articles/6/1419/2025/

You know... that timeframe is interesting and it's funny you mentioned it as I was looking through the H300 PDO index numbers again. In the monthly data, that was actually the last time it was appreciably positive. During 97-98. Greater than +1. And before that too. At times after that it has been above 0 to about 0.5 including during 15-16 but always fell negative again. It remains negative as of now, well as of June's number which was -2. A curious thing to add to this though is the MEI. Which appears to be tracking most similarly to 97-98. There's that year again and a record event of it's own time. Almost seems like that was some kind of turning point of sorts and now here we are just about 30 years later looking at some really intriguing metrics. H3 PDO: https://www.cpc.ncep.noaa.gov/products/GODAS/PDO_body.html MEI:

Looking at the SST changes vs last year at this time would give you the impression this is an entire Pacific ocean event. Pretty wild. Which is interesting too because the entire ocean is really making all of the right moves towards a +IPO. Or interdecadal pacific oscillation. Which would include a longer term +PDO. The south pacific especially, but the NH is trying too apparently. Not much reason to think that wouldn't continue given everything either. Going to be a really impressive event to watch. Already is. Can we flip the longer term pacific too? It's been negative for quite some time. I envision that would take a monster event to set in motion. Or at least look like one. I could be wrong of course, but it so happens we have one... Fascinating. Impact of the Interdecadal Pacific Oscillation on Tropical Cyclone Activity in the North Atlantic and Eastern North Pacific https://www.nature.com/articles/srep12358

There's probably going to be an incredibly powerful sub tropical jet this season too. A byproduct of the WQBO is further enhancement to that jet. QBO and ENSO Effects on the Mean Meridional Circulation, Polar Vortex, Subtropical Westerly Jets, and Wave Patterns During Boreal Winter https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022JD036691

Yeah, this sure is a -PDO. Fairly textbook looking actually in the North Pacific. Here's what makes that feature really interesting to me, especially in the face of this burgeoning super nino. Battle of heavyweights here. The interplay between these 2 should be fascinating. A deeply entrenched -PDO state vs potentially a record breaking el nino. When the PDO is out of phase with enso there is evidence it can act against it. Whether that is el nino or la nina. To the point of cancelling it out completely in the extratropics. Now, I am not sitting here thinking this event will be cancelled out by the PDO. That's not the point of this post. Nor do I think that will be the case. I do think there will be some sort of modulation though and think it will be interesting to watch how that goes and evolves. Additionally, could this be the event finally signaling a longer term change for the north pacific? I feel like that could be plausible given the magnitude and timing of it but who knows. Sometimes I see people dismissive of the PDO, however research suggests it's probably not a great idea to do that. Modulation of the Northern Winter Stratospheric El Niño–Southern Oscillation Teleconnection by the PDO https://journals.ametsoc.org/view/journals/clim/32/18/jcli-d-19-0087.1.xml

Looking through the JMA archives of VP anomalies. There's not really many years at all that are comparable in the strength of the Walker cell at this stage of the evolution. It's really only the super nino years that are comparable at all to this year thus far(basing this on the ONI data). The strong el nino years such as 57-58, 65-66, 72-73, 91-92, 23-24 don't even hold a candle to the VP obs over the past 30 days of this year. 87-88 also gets included in that group. That one gets a little bit of a shout out being as it's far closer in this regard than any of the others I listed. However that was a 2nd year event so I'm guessing that has something to do with it. That leaves 82-83, 97-98, 15-16 super nino's which I will post below along with this year. These are the 30 day means(!) Of those 15-16 I'd say probably looks the closest match to date although I'd also say that's probably because that's the most recent one. 82-83 not terrible. 97-98 seems to have ramped up a little more slowly than we're seeing now but that one absolutely gets included. Images below are this current year followed by the other 3 in chronological order. Yeah, this one probably ends up unprecedented in strength given all of the other data available. What that would ultimately look like is anyone's guess given an inherently small sample size. Guess we'll all find out.

Yes. Really a lot going on in this map, but man what a great plot. Those are the components of the H200 wave trains just like you're thinking. Also VP 200 anomalies in shading. Wave activity flux arrows. Plus the waveguides are the indigo bands. Sort of feels like we're looking at some of what's been discussed in here too. Namely, el nino taking command of the tropics with more of a -pdo flavor hanging on in the North Pacific for now. I'm really curious to watch how the north pacific evolves throughout this powerhouse event. It's an interesting case all around.