so_whats_happening

This is the last 2 week image so far for this event I will wait another 2 weeks but pretty sure we already peaked. You can still sustain easterlies in a +IOD event, such as this, and still have a weakening +IOD. The fact that this is already into the western IO means we are limiting just how much those values peak. I included a still image of 1997 when it had the strongest winds across the entire IO, it stretched from Sumatra to Somalia where we seem to currently have them more concentrated further west. 1997 was just better coupled to say the least.

Since we are talking IOD now here were the last 5 decent to very strong +IOD events: 1994-95: Peaked at around 2 in early November 1997-98: Peaked around 4 in mid December 2006-07: Peaked around 2.3 mid December 2015-16: Peaked at 1.3 in early November 2019-20: Peaked at 3.3 in early December So average timeframe to look for peak is from early November to mid December. Virtually all of them went negative by May with 2006-07 being the one that held on into summer. Used this since it was a nice visual approach but only goes to 1993 which is fine enough for seeing the evolution of these events. I wouldn't expect this to act differently compared to ENSO. https://sealevel.jpl.nasa.gov/overlay-iod/ Anyway here were the 850mb zonal wind anomalies starting from Sept 1. Most went positive around the beginning of summer and this year was no different. Just keep in mind peak timeframe when looking at these gifs and the lead up look to peak.

For sure forecasts are rough at best Ill have to check out the pattern globally with what looks like strong +AAM mode versus a strong -AAM mode. If I remember correctly a lot of wave break activity is -AAM regime and more blocking type pattern tends to be +AAM regime. Since -AAM tends to send energy poleward and helps with the SPV and TPV versus +AAM tends to focus things more equatorward weakening the SPV and TPV. This was one of those things not taught too often during schooling besides it being there, feel this is some grad level information.

Im still not entirely sure yet this is peak but we seemingly may be close, the SSTA has not reacted to the WWB like I thought it would thus far except in subsurface look. As for the PNA I have thought for awhile now this would be back and forth through the season especially with the ever present -PDO regime we have. I do agree though on the El Nino at some point in the near future should try to take hold January does seem reasonable and a slow decline in SSTA through the winter. We may see this being a similar look to last March but just anomalies in the opposite spots (last March was a warm east and cool up to about the dateline).

It is the same map from the atlas webpage just on a different site. Thanks for the 365 one.

Nothing suggests that at the moment but it wouldn't be invalid to have a wave rising up in 4-5 from time to time. 6-7 look ehh so weak passing (near null) to pop out near 7/8 border and travel to 1 before circling around again. Way too difficult to say that is what will happen but if we see any noticeable weakening of the subsidence from the +IOD going forward then it becomes worrisome as that would allow a potential more solid wave through those regions.

I would consider it neutral but yea nothing seems wrong. If you look at the plot further down you can see most of Sept and Oct were indeed negative. Very different from the strong +AAM pattern that was around in May and June which was in tandem to a large warming episode across 3.4. This would suggest that El Nino atmospherically is still there, somewhat, but there are other things driving what we are seeing at the moment.

Essentially not allow MJO movement through 1-2-3. Technically 1 does also present itself in the EPAC as well. So we may still see it push into 1 going forward but get shunted back into null if the cooling across the IO continues.

For anyone looking for a current look to AAM this seems to update often enough. https://phillyweatherauthority.com/global-wind-oscillation/ OISST finally updated and had brief spike to 1.84C now sitting around 1.7C but not liking that warming in the NW PAC/ Japan region again. IOD continues to slowly weaken due to the spreading of the cold anomalies westward but we are still technically positive since the difference is still positive overall. This may lock up any 1-2-3 in MJO movement as we go forward. With such warm anomalies near the Aleutians there may not be much of Aleutian low this year and something shown by the latest Euro update. Cooling the waters in the NW Atlantic giving us that tri-pole look. Waters of the Mexican coastline down to South America are cooling still which should allow at some point before the new year 1+2 to be cooler than 4 anomaly wise. It is likely that Nino 3 has peaked back at the end of August/ early September ~2.3C we should be nearing peak in 3.4 this month, whatever those values may be, then continue the slow decay as we go through winter. By spring this should be a shell of itself (March area).

So far the GFS is the only one showing this strong of WWB event in a few days. Others do have it but not nearly as pronounced. Otherwise we are continuing to see the westward shift of the easterlies in the IO reaching the African coastline so we really may have already peaked in IOD territory as the areas in the Western IO start to cool. Trades overall not giving up across most ENSO regions. It looks as though we are probably near the sustaining part of this Nino as for values. Again possible to push to 2C as some point soon but would not expect much past that. This event may finally kick the dateline warm pool east.

Im so bad with actually making it on time, i tend to forget until i see its the first. Didnt help i couldnt login for like 2 months.

Right id rather not rely on a winter that has an SSW, would rather it just enhance the winter already in motion. Ill just wait and watch as we get toward December for the most part im not too concerned about the path we are going thus far. Should be an interesting month.

Yep but you also need to watch out for too early of an SSW, especially if it is not a major event, as there will be recovery before the final warming takes place. So anything before January and you run the risk of losing February snow potential with a recovering SPV. There is a sweet spot needed in not only the wave activity but timing.

I would be awfully careful about SPV forecasts that far in advance. You can typically start to see it on models in the 15 day but it is recommended to wait for 10 days max. You want extensive wave breaking events in the troposphere to help create the waves along the SPV rim. It also is nice to Urals blocking occur as this usually is an early indicator something may be on the way. You also want to see more than a wave 1 flux happen, wave 2 is the desired for many of us in the east which means the atlantic/european side needs to get involved and this has been an issue over the years. It is also important to remember that just because an SSW may be occurring does not mean it affects us in the same manner we think it will. I have some papers i can share from over the years when i get to my computer. As bluewave said it is rather rare to see anything happen before the new year, typically it is after mid january we see enough wave activity to induce a warming event whether it be a mid grade warming or a major event.

I wonder if there is a connection of +AMO and -PDO phase and vice versa, also when they are in tandem +/+ or -/-. I never really took the chance to see if this was something or not and since they are multi decadal oscillations im curious if there is something to it like when we have an extremely +AMO do we tend to have more -PDO?

It takes some time for things to work through if we do hit that threshold even. If anything 3 should warm up more so than 3.4 but we shall see. As far as trimonthlies to get to that range for NDJ, as you mentioned where peak would be per your thoughts, we would need to have 3.4 sustained around 2.1-2.2 for the rest of November and hold that for three full months. We have yet to see sustaining effects after each warm up period we tend to get this warmth to surface and then 2-3 weeks after it dies off and begins to cool. Maybe this time is different? To be quite honest I don't see this being an issue going forward, forcing is still establishing much further west than a typical strong borderline super El Nino would be. 2015-16 was further west than 97-98 and it seems like that type of trend may continue with this event in forcing location.

Here is the CPC update through much of October the 30th should update next week.

Here is the latest TAO/Triton from mid October to the most recent. Not much changed in the beginning portion of October from 1st-15th area but look was overall similar to what it looked like on the 15th. You can see the shifting of the warm pool under western 3.4 and 4 starting to shift eastward and connect with the thermocline dropping down further east. Not much change in overall surface temps in the east thus far and if we are to it will be in the next two weeks with a push of warmer waters. This will be the push to 2C that I mentioned before, how long it stays there is very dependent on what happens with wind forecasts. It looks like mid November to mid December may be the 2C timeframe after that it may be more just about sustaining those anomalies than rapidly deepening but will have to wait and see. Of note the WPAC subsurface is gaining some steam too so this very well could be the last push of this Nino for more warming episodes but again will have to wait and see for the full reaction of this KW. Forcing still looks to hold up around the dateline with some spottiness in the far EPAC.

@Terpeast So I went and just did a quick june-august look in the northern hemisphere. I mean it kind of does speak for itself in the 15 years leading to 2007 and 15 years after 2007. No real rhyme or reason to the dates. I'm sure if we did it into 5-10 year bins we would see the changes occur.

This could be explained by the drastic shift down in ice volume around that time. Just a thought of course.

We need the Atlantic/European side to cooperate too don't want a large scale wave 1 displacement when something does take hold.

Yea my bad went into the monthly break down and saw the 14" listed there thinking it was 13-14. Went back and edit the mistake was year off on both those references.

Yea 21/22 (i believe this was more se this year than s, jersey shore delaware folks) was also another year where they got hit quite a bit. Rough being nearly 60 miles straight shot and getting half the snowfall.

I was referencing lancaster area we had 13" that year.