EasternLI

I'm kinda impressed with the way this MJO is progressing. Plus it's of the slow moving variety. Which is good in this case because those are the more likely versions to affect the circulation. Velocity potential tells a better story then the RMM charts. It's interesting too, that models continually have tried to kill this wave in extended ranges. Since November really. Yet it still continues on. 

These are both from the GEFS. Check out where we were and compare it to where we are headed. Effectively muting the MC region, while allowing the western hemisphere to be more dominant in the forecast period. Cold enso base state is also is also identifiable on these but not overpowering everything like our most recent La ninas have. 

Top image I have saved from the 12/12 00z GEFS. With a forecast ending at 00z today, the 29th. Bottom image is last nights 00z GEFS. 

7 hours ago, so_whats_happening said:

Depends on what type of SSW takes hold and what pattern should evolve from this event. If we get a solid wave 2 potential that shows up it could reshuffle the pattern in our favor a lot better than a large wave 1 response like we saw last year. Of course a wave 2 response doesn't always mean ridge west/trough east. The propensity of the atmospheric pattern to not fully revert back to the constant deep -PNA has been a nice change-up for this year even with a La Nina starting to actually build properly.

The SSW (which this one I actually consider significant) that came in the beginning of January 2024 I think just linked up in the wrong spot for us. We had a fairly strong 500mb ridge in SE Canada already in place leading into that strong wave 1 response so it locked the pattern up rather quickly and we just could not shake it we also did not see the breakdown of the SPV fully so once the warming was done it started to gather itself together again. Talk about unlucky. Now if we get significant wave 1 or wave 2 (preferably) with an atmospheric pattern of ridging into Alaska and retracted Pacific jet like we have been seeing off an on I wonder if the results would be different, I mean they should just not sure how it would translate yet.

https://acd-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra2/flux/vtn_10_2024_merra2.pdf

https://acd-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra2/temp/t60_90n_10_2024_merra2.pdf

We had a heat flux but not a significant stratospheric warming event that took place. It was at best a displacement event that happened to work a little bit in our favor instead of roasting us like what typically happens in a Wave 1 response. I don't want to discredit that it was a stratospheric warming event but it was nothing noteworthy. Maybe it was because the SPV was already well established and strong that we didn't see a significant rise in temperature other than to near average? 

This warming event we just had helped relax the SPV and bring it back to what is typically average for this time of year so any further attacks will start to impede in the strength much more, if we do see these attacks come to fruition. As for the snow/cold possibilities that come along with it I think the important thing would be to have much more wave 2 response, this means help not only from the Alaska region (which is the typical location of the 10mb ridge) but also over northern Europe. We need poleward flux/ wavebreak events (negative tilted troughing leading to large blocking highs) to happen and that seems to only be on the Pacific side right now, the Atlantic has been having more equatorward wavebreak events which still helps to keep the SPV intact. We had a very strong wave 1 response last year that gave us a blip of winter weather hopefully it is not a wash rinse repeat scenario.

This was last years wave 1 response compared to this years (seen above). Of course the SPV was a bit weaker last year so it helped to rock the boat a bit more compared to this year. Angle of attack is also extremely important as to the proper effects into the mid latitude maybe because the Pacific jet was a bit stronger due to a deep -PDO state that was not changing caused it to have a different location for the atmospheric ridging location? May be something worth looking into down the road.

Great post. I've done a fair amount of reading on this topic over the last several years. I think your thoughts are right on the mark as far as lining up with said reading. One thing I remember seeing, and I don't remember where, is that if one is looking for an ssw to deliver a colder pattern. There's a higher probability of that occurring from one that initiated during an already colder pattern. Which sounds like it lines up with your thinking on the phenomenon and kinda makes sense to me. 

The PDO should continue to climb too, with the progged pattern. Which is interesting. This is a 5 day mean from the 12z eps. 

Impressive poleward ridging from the 18z GEFS heading into the heart of January. 

It's interesting also, to see the eps weeklies now weakening the SPV pretty substantially by mid January. Which would be consistent with an mjo 7 response. 

I think from a very broad perspective, all of the 00z ensembles basically showed the same thing. When you loop them. The North Pacific low retrograding to the dateline. Which causes the GOA low to break on the west coast. There would be an emerging ridge on the west coast in that scenario. Or wherever that wave breaks. Eps shows the same progression. Canadian ensembles are more aggressive. This is the 00z gefs 

34 minutes ago, bluewave said:

It will be interesting to see what happens. My one concern is that the MJO is currently contributing to the pattern rather than running it. We continue to get more of an El Niño influence blending in with the EPAC forcing. While the CFS and EPS have more of a MJO 7 look in early January, the GEFS looks different. The GEFS has forcing near 120W which places a trough near the Baja. So the GEFS doesn’t have a clean MJO signal like the EPS and CFS. Not sure which way it will go at this point since competing influences make the very long range more uncertain. Plus you can see some La Niña influences in the GEFS.
 

 

 

Yeah, it's all making this year an interesting one to follow. I'm curious how much of that suppressed phase we can nose over into 120E or if we can. 

The trend in recent days has the mjo continuing to slowly move eastbound into the Pacific. Gefs from 00z continuing that idea and with a decent amplitude as well. Starting to get into the phase 7 space at the end of these now. Would be great to see it keep moving, and that does look like a realistic possibility as of this moment. 

8 hours ago, brooklynwx99 said:

@snowman19 seems like you don’t think the trough will retrograde? if this truly is acting like a Niña we should see the jet relax and the trough will retrograde as a result

Seems like the events of November have left the atmosphere in a more Niño-like state. If the MJO is effective in the Pacific. Probably another WWB and +EAMT in January?

https://x.com/Met4CastUK/status/1864797137227387090?t=K3C8XrFImAvNwHt5_u21Mw&s=19

The westerly QBO theoretically could assist to temper some MJO convection in the MC region this winter. So it will be interesting to see how everything progresses moving forward. Here's some key points about this relationship. It seems like this could be a good test subject ahead of us. 

Modeling evidence of QBO‐MJO connection: A case study

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL089480

"The boreal winter Madden‐Julian Oscillation (MJO) is modulated by the Quasi‐Biennial Oscillation (QBO). The MJO becomes relatively strong during the easterly QBO (EQBO) winters but weak during the westerly QBO (WQBO) winters."

"When the lateral boundary conditions are switched with those of WQBO or strong WQBO winters, the MJO becomes weak over the Maritime Continent."

QBO modulation of MJO teleconnections in the North Pacific: impact of preceding MJO phases

https://www.nature.com/articles/s41612-024-00565-w

"It is found that the Rossby wave trains induced by MJO phase 6–7 exhibit greater strength and robustness during the westerly QBO winter (WQBO) than during the easterly QBO winter (EQBO), although the MJO itself is weaker during the former. This counter-intuitive dependency of MJO teleconnections on the QBO is attributed to the preexisting MJO teleconnections prior to the MJO phase 6–7. The MJO phase 6–7 is more frequently preceded by stronger MJO phase 3–4 during the EQBO than during the WQBO. The preceding MJO phase 3–4 teleconnections, which have opposed signs to the MJO phase 6–7 teleconnections, result in a considerable attenuation of the MJO phase 6–7 teleconnections by destructive interference."

There were recently twin TC's in the Indian ocean. Pictured below on 11/27 12z. Who's influences appear to be waning currently. It'll be interesting to see how everything trends this month. 

2 hours ago, brooklynwx99 said:

my initial impression of late Nov into early Dec so far is that the persistently +AAM that's being forecasted combined with +EAMT event is extending the Pacific jet more than is typical of La Nina. extensions are often favorable for us, and I believe these factors are overriding the largely unfavorable MJO passage

this general pattern favors +EAMT into early Dec, allowing for a persistently extended Pacific jet that leads to an Aleutian trough. the MJO isn't a silver bullet, and i do think we're seeing a break in the typically strong MJO correlation. never been happier to be wrong about a forecast, let me tell you

I have an observation to share regarding the MJO/status of tropical convection. It's been quite interesting this month. I think I can provide an explanation and illustration of why it's rendered ineffective currently. I think it's actually a really good example of a time when the MJO just isn't going to mean very much to us. The image below is from the JMA. It has OLR overlayed with 200MB VP anomalies. Note how the center of action along with the bulk of the forcing this month is south of the equator. When that happens, it's just not going to effect the NH very much if at all. It seems like this is also leaving some room for the Pacific jet to be more equatorward rather than poleward. Which I've seen you make mention of in a different post. So as long as this continues, which could certainly be debatable, I don't think the MJO is going to be telling anyone much of anything. And maybe we can actually achieve some Aleutian low this year when that equatorward jet extends like guidance is currently showing. 

Yeah, 65 here too. It feels glorious, ngl.

Then the gfs spits this out after I said that of course. Clown range here, but the interesting thing about this, the eps has a couple clusters that show something similar to this too. May be nothing, but worth a mention I think. 

Just starting today and going ahead, the ssw will now be included in the initial conditions on modeling. So it will be interesting to see what changes, if anything, as that becomes the case now. There's evidence available that suggests this makes a noticeable difference with predictability of how they play out. I'm not saying to expect anything crazy, just that this is a point where potential changes could occur on modeling. Or not lol.

1 hour ago, snowman19 said:

Had to drop in to agree with you on that. The Niña system is still in full effect. Also, I’m not so sure the SSWE is going to be all that effective either. This event is nothing like 2018, it’s a displacement event, adding to the uncertainty and there’s destructive interference from the +QBO and -AAM, serving to delay and convolute everything. If there’s even any tropospheric response it may not happen until the 2nd week of March. This tweet chain does a great job of explaining what’s going on

Yeah, I've been saying it's not really impressive looking.... The latest gfs cross sections suggest this is not making much progress downward. Best to wait until it's underway and then see what models are doing, though. But it just looks uninspiring to me so far. 

Toss that MJO idea to the moon. Not happening. It's not going to be effective....

25 minutes ago, SnowGoose69 said:

Neutral ENSO winters which occur near the solar max historically are very bad for some reason...there has been many theories as to why...most likely its that the AO/NAO simply average strongly positive in those years but it may also be that without the La Nina/El Nino you lose some ability to get pronounced ridging or troughing in some locations so the pattern has a tendency to be more zonal and the bad AO/NAO amplify that issue 

Weaker walker circulation is just not good, maybe. We want some amplitude, but too much isn't good either. It's interesting to think about.

21 minutes ago, SnowGoose69 said:

There is next to no chance its strong.  I'd say there is a better chance of neutral ENSO next winter than a  strong Nino

I like a weak to moderate modoki el nino next year. We're following EOF2 from the following paper fairly well. Which leads to that. I agree neutral isn't off the table just yet. Whatever it is, it is not similar to EOF1. Which leads to the east based classic events. 

Leading modes of tropical Pacific subsurface ocean temperature and associations with two types of El Nino

https://www.nature.com/articles/srep42371

2 hours ago, EastonSN+ said:

Yeah, I learned that I never want to witness a triple dip la Nina ever again.

Yes, this is usually my rule of thumb with that. It's funny too, I thought this winter would suck back in August. Then the blocking became a possibility and I reconsidered everything lol. Because blocking is what you look for in la Nina if it's going to be any good. That was an interesting development. It failed, sometimes they do. Is what it is. 

1 hour ago, EastonSN+ said:

Please correct me if I am mistaken but I believe the following is best enso state to worst:

Weak El Nino

Moderate El Nino

Weak la nina

Neutral

Moderate la Nina

Strong El Nino

Strong la nina

Swap neutral and moderate la nina with each other and I agree. Neutral sucks, too strong in either direction does too. Just a very basic guideline. Many other variables to consider. 

It does look like the ssw is going to actually go off. Meeting the technical wind reversal definition. In addition to the eps, the GEFS is now 100% for the past few runs now. Will be interesting to see how/if it works with the troposphere following this. Be curious to see some cross sections on what is happening once this gets underway. Never can be certain with these things but worth keeping tabs on. It's something to watch at least. Hope everyone enjoys this very nice mild Friday on tap. 

13 minutes ago, EastonSN+ said:

IMO getting out of this 3 year la Nina will work wonders in so many ways.

 

Well, it can't get much worse 

I don't hate la nina. Some of them can be good. This one just has it all wrong lol. Tired of it though, I welcome a change. 

4 minutes ago, EastonSN+ said:

Annnnnd of course the wave dies again in 7.

We have a legit shot at lowest historical snowfall.

Good to get it out of the way! Prolly won't see a winter this bad again in our lifetimes.

Here's a great example of why extreme caution is always needed with those charts. If we look at what is actually occurring on the model. We can see the MJO wave moving right along. However, we can also see the warm pool convection associated with la nina never fades away enough as this is occurring. This renders the whole thing less effective. This is the destructive interference we sometimes mention. We'd really want something strong enough to fully disrupt that in order for more meaningful changes. Something we just haven't seen much this year. So that forecast crashing into the COD is really trying to say it's retaining its dominance in spite of the MJO. Which is a problem for us this year. That positioning right there is the anchor for a western trough. So we end up stuck with that as much as we are. Now, let's shift that thing closer to the central Pacific next year hopefully. Then you get a western ridge instead. 

Not sold yet on a technical ssw even occurring. Some warming, sure, but the gefs seems to have backed down on wind reversal today at 00z. Plus, the 06z run now only has 60% of the members on board with it. So it's still possible it doesn't even occur this time either. I realize the eps weeklies were bullish yesterday. However, I'd prefer to see total agreement. Not going the other direction. Especially as we're getting inside of day 10 now. You'd really want to see a strong event too in hopes of impacting where it matters. This is just uninspiring so far IMO. I also agree with the sentiment that even if one should occur, it doesn't necessarily have to matter for us. This is always the case and should be baked into any thinking about this topic any year.

The purpose of the long range pattern discussions is not to identify any individual storm systems. I personally think it's a misinterpretation to think of it in that way. You can get snow events in a bad pattern. Nobody has said that can't happen. I certainly haven't. The thing is, favorable longwave patterns offer an easier path to accomplish the certain combinations of synoptic features we're all in search of. That is the reason why they are often discussed. Not to identify anything specific. At least it shouldn't be. It's simply an attempt to identify windows where it's easier to find something specific. It's really two separate things, in my view. 

0F IMBY currently. That's impressive here on CAA. Usually that happens with rad cooling here. Yesterdays hrrr did alright locally here. Euro too.