griteater

Oct release of Copernicus C3S follows with the trends of the seasonal models slowly edging away from a stock El Nino look. Here is the 3-run trend of the C3S for January (500mb): Of the Copernicus model suite, the JMA is the most wintry looking. It starts out wintry in the west in Dec, then goes -EPO/+PNA in Jan-Feb. With the low frequency tropical forcing focused in and around the dateline, I'd say some bits and pieces of those ideas aren't far-fetched...just maybe not as locked in as the JMA is showing. Here is the JMA 850mb temp map for January:

This is a strange post. Your images are solely for Dec, yet your wording implies that it is a correlation that applies to the full winter...you stated, "Without a strong Modoki signature, the warmth in Nino 4 is an extraordinarily powerful warm signal for you guys in the East." Dec is a known warm signal in the east when Nino 4 is warm, but that changes after the new year. Here are the temperature images for Dec / Jan / Feb when Nino 4 is warm

Yes, there is indeed a competition lol

Paul Roundy has spoken...

CPC uses a moving 30 yr average for SST Nino region anomalies for ONI: Climate Prediction Center - Monitoring & Data: Ocean Niño Index Changes Description (noaa.gov) "Due to a significant warming trend in the Niño-3.4 region since 1950, El Niño and La Niña episodes that are defined by a single fixed 30-year base period (e.g. 1981-2010) are increasingly incorporating longer-term trends that do not reflect interannual ENSO variability. In order to remove this warming trend, CPC is adopting a new strategy to update the base period. There will be multiple centered 30-year base periods that will be used to define the Oceanic Niño index (as a departure from average or "anomaly"). These 30-year base periods will be used to calculate the anomalies for successive 5-year periods in the historical record In real-time operations, the past 30-year base period (e.g. 1991–2020) will continue to be used to compute the departure from average. However, CPC will create an additional 30-year base period every 5 years (the next update will be at the beginning of 2026). When these 5 year updates occur, the ONI values over the most recent decade will change slightly because of the inclusion of more recent data."

VP image for Mar 19 to Jun 19 of this year. Uplift max in W Pac / Subsidence max in C Amer VP image for Jun 19 to Sep 19 of this year. Uplift max W of Dateline / Subsidence max in far E Pac and W Indian Ocean VP image for Jun to Sep for Strong and Super Ninos (ONI) since 1980. Uplift max E of Dateline / Subsidence max in Indonesia VP image for Jun to Sep for Moderate Ninos (ONI) since 1980. Uplift max near and E of Dateline / Subsidence max in Indonesia and Far E Indian Ocean VP image for Jun to Sep for Weak Ninos (ONI) since 1980. Uplift max near and E of Dateline / Subsidence max in Far W Indian Ocean and E Africa VP image for subsequent winter (Nov to Feb) for the same Weak Ninos (ONI) since 1980. Uplift max near Dateline and Indian Ocean / Subsidence max in the Caribbean Bottom Lines: 1. The low frequency VP pattern (3 months or more) this year hasn't changed much going back to March. 2. The Jun to Sep VP pattern this year is most similar to Weak El Ninos (ONI) when comparing with all El Ninos since 1980. 3. My guess is that the low frequency VP pattern this winter will be similar to the Weak El Nino winter composite with an uplift max along the Dateline and a subsidence max in the Carribean and South America. 4. My guess is that the MJO will become more active this winter and will play a substantial role in the subseasonal / monthly pattern 5. The persistent and strong subsidence region over C America / Carribean / Gulf of Mexico this year is noteworthy and may have contributed to the extensive summer warmth in AZ/NM/TX/LA.

I said if the stratosphere is 'ice cold' in Oct-Nov, "we'd at least partially have to attribute that to the excess water vapor in the stratosphere from Hunga Tonga." And I wouldn't want to fight that battle as we go thru winter. Yes, back in March, the water vapor had propagated into the NH polar cap, but the Jan-Mar period is more subject to dynamic strat warming compared to early winter (i.e. dynamic wave driving can overcome other potential hindrances in mid-late winter...applies to this winter as well as Dateline forcing plus the -QBO should help with that). As far as the early 90's, I feel that, in addition to Pinatubo, you also had the descending solar in some of those years <and> elevated CFCs that favored ++AO. These are just my thoughts. Do I have all the answers? No.

I think it could. What I've said is that I want to see how the stratosphere is looking in Oct-Nov. If it is ice cold, I'd think we'd at least partially have to attribute that to the excess water vapor in the stratosphere from Hunga Tonga. If it's not ice cold then, I think we'll be fine going into winter.

This is the toughest part of seasonal forecasting these days IMO. It's hard enough without climate change interference. Now you have to keep up with all of the CC elements and how they impact the forecast.

Yeah the early 90's were loaded with reasons which seemed to favor a heavy +AO. In addition to Pinatubo and some years in the descending portion of the solar cycle, you still had elevated ozone-depleting CFCs in the atmosphere prior to the positive effects of the Montreal Protocol of 1987 kicking in

Yeah, that's really weird. I don't recall seeing that in the past. You can set your interval and range on the entry page...but not sure why the ranges are missing on the output

Good link here for SST re-analysis - psl.noaa.gov/cgi-bin/gcos_wgsp/printpage.pl You can compare older years against its climate period. Image below is Oct-Dec 1955 compared against 1930-1960...hardcore -PDO & La Nina

Yep, as seen on this 1st chart below, in late 2015, as the -QBO was descending from 3mb to 10mb, it abruptly stopped its progress and the +QBO lasted close to 2 years at 30mb from roughly May 2015 to April 2017. Something like that had not occurred in any year back to 1953 as seen on the 2nd chart. It looks like there was also another near disruption in the 2019 to 2021 timeframe (can see it on the 2nd chart). Everything seems pretty normal so far this year with the -QBO progression.

That's how things 'should' work with the MJO during stronger El Ninos...but as bluewave has previously referenced, the MJO was more active than expected during the 2015-2016 El Nino with warmer SSTs in the W Pacific. Here are Dec 2015 and Feb 2016: Paper: Distinctive MJO Activity during the Boreal Winter of the 2015/16 Super El Niño in Comparison with Other Super El Niño Events | SpringerLink Many previous studies have demonstrated that the boreal winters of super El Niño events are usually accompanied by severely suppressed Madden-Julian oscillation (MJO) activity over the western Pacific due to strong descending motion associated with a weakened Walker Circulation. However, the boreal winter of the 2015/16 super El Niño event is concurrent with enhanced MJO activity over the western Pacific despite its sea surface temperature anomaly (SSTA) magnitude over the Niño 3.4 region being comparable to the SSTA magnitudes of the two former super El Niño events (i.e., 1982/83 and 1997/98). This study suggests that the MJO enhanced over western Pacific during the 2015/16 super El Niño event is mainly related to its distinctive SSTA structure and associated background thermodynamic conditions. In comparison with the previous super El Niño events, the warming SSTA center of the 2015/16 super El Niño is located further westward, and a strong cold SSTA is not detected in the western Pacific. Accordingly, the low-level moisture and air temperature (as well as the moist static energy, MSE) tend to increase in the central-western Pacific. In contrast, the low-level moisture and MSE show negative anomalies over the western Pacific during the previous super El Niño events. As the MJO-related horizontal wind anomalies contribute to the further westward warm SST-induced positive moisture and MSE anomalies over the western tropical Pacific in the boreal winter of 2015/16, stronger moisture convergence and MSE advection are generated over the western Pacific and lead to the enhancement of MJO convection.

My eastern U.S. winter 'fears' have slowly migrated from snowman forcing (E Pac) to bluewave forcing (E MC / Far W Pac) , though I reserve the right to change lol. Thinking now is that the low frequency forcing is going to be favorable for the most part. I can't imagine the low frequency forcing being focused west of 2014-2015 and what the JMA & JAMSTEC are showing, which is just west of the Dateline...and we don't have any indication that it's going to plow east in 82-83, 97-98 fashion either. Bigger question may be how much destructive interference we see from the MJO over the course of the winter.

Taking the long view, the VP pattern back to March this year is most similar to a bit stronger version of 2014 when comparing with other El Ninos since 1980 (though not a perfect match) VP Anomaly Hovmoller for 2023: VP Anomaly Map for Late March to Early September 2023: VP Anomaly Map for Late March to Early September 2014:

^ JMA and JAMSTEC are banging on the precip/uplift being west of the Dateline, a 2014-2015 look, but likely with stronger uplift this go around (stronger Nino)

Maybe for once this kind of model heat bias will carry over into winter

The default page for the Copernicus SST plumes is for Nino 3 instead of 3.4 (which is dumb). So, I'm wondering if you were looking at Nino 3?? It has the Nino 3.4 value here in Sep around +1.5

MEI Charts below comparing this year to Super Ninos / Strong Ninos / Moderate Ninos / Weak Ninos. This is MEI v2 data which only goes back to 1979. I used 2 Bi-Monthly readings for better smoothing with the chart lines. As has been discussed in here, the current year is most similar to prior Moderate and Weak El Ninos, and most dissimilar to the Super El Nino years.

Copernicus Multi-Model Seasonal Ensemble (C3S) September update is out. Lots of data / maps if interested: Charts | Copernicus and C3S Model - Global | CyclonicWx Just glancing thru everything, I'd say they bumped a touch more super nino-ish with less eastern U.S. troughing Here is a compare of the Aug run vs. the new Sep run for January (500mb pattern) On the bright side, the -OLR and -VP Walker Cell uplift zones bumped west this run along the Dateline (January maps shown)... For the Euro component of the output...for stratospheric zonal winds at 10mb, it's still showing a weaker than normal strat PV develop by Jan, though not quite as robust as last month's version

In watching the UKMO, it has actually been on the higher end with SSTs. Today's reading is down a tick to +1.61

I eyeballed the 40mb numbers from the QBO chart from the Free Univ of Berlin - qbo_wind_pdf.pdf (fu-berlin.de) Unfortunately, they have quit updating that chart, but you can get current data from this page, though in a slightly different format: The Quasi-biennial Oscillation (QBO) (nasa.gov) Don't have a great reason why I settled on using 40mb. Some people use 30mb, some 50mb. Some of the strat papers use something like 45mb averaged over Dec-Jan or Jan-Feb. One reason was that I wanted to capture years like 86-87 and 09-10 as -QBO winters as both of these were -QBO at 30mb and +QBO at 50mb....but I like the Berlin chart, and it helped me understand the progression of the QBO more than any other when I was first learning about it.

Ha, indeed I don't have a response because the stratosphere did indeed warm severely (SSW) due to dynamic processes (an extended period of elevated heat flux) right at the time that those + water vapor anomalies kicked in (in January). All of those processes affecting the strat PV and associated AO/NAO are complex, as you know. It's possible that the + water vapor anomalies won't have any effect this winter or that the anomalies aren't high enough to cause an effect. It's also possible that we see a cold stratosphere develop in Oct/Nov, in which case, I would have to believe that the elevated water vapor anomalies are at least partly to blame. If we can just avoid that cold stratosphere scenario in Oct-Nov, we should be in a really good position for -AO/-NAO this winter given El Nino / QBO / Solar <AND> the seasonal model support.

The monthly curve spikes a bit to kickoff 1992 so I have it still in the solar max phase, but it's a close call. I would call the winters of 93, 94, and 95 as descending. That paper probably goes into the specifics on how they designate each phase within the solar cycle curves.