2025-2026 ENSO

[snowman19]

36 minutes ago, George001 said:

I never really thought December would be a huge snow month for the I-95 corridor, I thought it would be a good month though. I still think that’s the right idea. However I disagree that there is nothing at all to support I-95 snowstorms in the next 14+ days. There is a window next weekend. Depends on how much that northern energy digs. I do however think we are seeing early signs that some of the early assumptions that you made about this upcoming winter could end up being wrong. Just curious what your thoughts are on that? Are you adjusting your Jan-Mar thoughts based on some of the things we have seen recently with the PDO, MJO, SOI and polar vortex? Or are you sticking to your guns? 

As far as February being canonical Niña? Nope and if I do change it, it won’t be until we are into January 

[GaWx]

1 hour ago, snowman19 said:

Day 14 on the operational 18z GFS 

 But the idea of a big Arctic plunge 12/12-17 deep down into the US (possibly from two highs per GFS) is becoming increasingly likely based on model guidance. This is very believable considering it would be during an EPS progged longest phase 8 in 50 years along with the highest % Dec 5th snowcover in the Midwest since at least 2002.

 This is also setting the table for a potential quite cold Dec/Jan considering the -PNA Dec -ENSO analogs suggesting a +PNA Jan, which would make it likely that DJF would end up colder than normal for much of the E US even if we get the favored mild Feb.

 The Euro Weeklies would have to bust badly to allow for a +PNA, but it’s been too strong with the SER since just before Thanksgiving.

[MJO812]

What warmup ? The same people that said a warmup in early December think the same thing about the end of December.  This month is going to end of very cold. 

[SnowGoose69]

1 hour ago, MJO812 said:

What warmup ? The same people that said a warmup in early December think the same thing about the end of December.  This month is going to end of very cold. 

I think back a few days ago and ensembles had that ridge already slid across to the MA by 12/13.  Look at 162 hours today its not even close.  There is no doubt they've been way too warm beyond D8 for awhile now.

[leo2000]

A lot of people are forgetting all it takes is a transitional +PNA to get a big storm to pop on the east coast. Speaking about that models seem to be showing that on the 13th of December. I watch that period very closely for a miller b snowstorm. 

[PhiEaglesfan712]

5 hours ago, Stormchaserchuck1 said:

I posted in this thread like 4-5 times a long time ago that weak-negativeENSO and strong -QBO has this strange coincidence of having super cold December's. 1989 and 2005 were examples. QBO is a stratosphere index so I didn't want to make the physical connection, but mentioned that it would be something if it happened again. And sure enough, it did happen again. This December is looking like one of the coldest in the eastern 1/2 since 2005. 

December 2010 was colder than December 2005, at least where I live.

05 34.4

-3.0

10 32.7

-4.7

If we do get colder than 2010, then 2000 would be next:

00 31.3

-6.1

Come to think of it, there's a weird coincidence that -ENSO Decembers in years that end in 0 or 5 (doesn't matter the strength) tend to be very cold in the East:

[snowman19]

[bluewave]

20 hours ago, BlizzardWx said:

I know MJO 7 is supposed to become more favorable later in December compared to early in the month or November, but I am worried that the extended jet (relating to what you were mentioning in the west Pacific) will continue to keep things out of phase with expectations. I guess we will see. 

The current standing wave in MJO 4-6 will consolidate the forcing there leading to a jet extension in around 10 days and the ridge getting pushed east with the falling AAM.

[MJO812]

Expect cold most likely for the rest of the month with a  negative WPO and MJO in phase 8.

[MJO812]

 

[BlizzardWx]

18 minutes ago, bluewave said:

The current standing wave in MJO 4-6 will consolidate the forcing there leading to a jet extension in around 10 days and the ridge getting pushed east with the falling AAM.

I see you used the +/- 5 latitude VP. I know some sites use a broader area like +/- 15 degrees and with anomalies. Do you find this selection to be the most relevant? I'm still wading my way into understanding the MJO better.  

I attached some GEFS plots for the current precip and VP anomalies. I think a good chunk of what might be more 7-8 forcing is below 5 S with the record warm temperatures off of Australia. But I definitely see the 4-6 forcing within the +/- 5 latitude band too. 

[Krs4Lfe]

50 minutes ago, bluewave said:

The current standing wave in MJO 4-6 will consolidate the forcing there leading to a jet extension in around 10 days and the ridge getting pushed east with the falling AAM.

Just in time for a mid month warmup, as was a bit expected, but hopefully it doesn’t become like the infamous December 2023 jet extension where we roasted for the rest of the month 

[Terpeast]

After several 11-15 day warm ups have failed to materialize in the past few months, I remain skeptical of such warm ups in the near future. Of course that will change, and my guess as to when the next extended warm up will be is february. We may get mild for a week or so mid-Dec, but I think its only temporary. I drew in green below the next mjo wave to get out of the MC. There is a hint of this even within the 5N-5S band (its stronger with 15N-15S and thus more influential). So I wouldn’t be surprised to see that hint strengthen into a signal that’ll eventually play out and bring us back to colder weather in late Dec into  Jan. 

[donsutherland1]

If the WPO relaxes from its forecast values of -2.000 or below, other teleconnections can gain influence over the pattern. The EPS currently forecasts an EPO+/AO+/PNA-/NAO+ regime toward the end of its run. If the WPO rises, that could allow ridging to expand across the CONUS with warmth following after a few days lag.

December 30-31, 1999:

The December 30-31, 1999 composite 500 mb map is one example of how unfavorable teleconnections overwhelmed a weaker WPO-. Then, the WPO was still impressive (below -1.000) but it was not at the extreme values necessary to overwhelm the pattern.

Milder conditions rapidly spread into the East.  Despite much above normal temperatures to start January 2000, the month wound up colder than normal. Late January (January 24-27 timeframe) saw a major snowstorm in the Southeast and lower Mid-Atlantic region.

For now, it looks to remain generally colder than normal through around December 20th. Nothing is cast in stone for the remainder of the month, though some temporary relaxation is plausible. IMO, the odds remain against a complete breakdown of the pattern and the onset of a sustained warm pattern during the closing 10-11 days of December. Still, it's worth watching the evolution of the guidance.

I suspect that there could be an increased risk of a pattern breakdown after mid-January, which often happens during La Niña winters, but that's in the speculative range right now. The PNA could play a larger role in how January evolves.

[PhiEaglesfan712]

49 minutes ago, Krs4Lfe said:

Just in time for a mid month warmup, as was a bit expected, but hopefully it doesn’t become like the infamous December 2023 jet extension where we roasted for the rest of the month 

December 2023 was an all-out torch. Plus, it was in strong el nino. It's nothing alike to what we have now.

The cold air is there this December. We just need a notable snowfall.

[MJO812]

1 hour ago, Krs4Lfe said:

Just in time for a mid month warmup, as was a bit expected, but hopefully it doesn’t become like the infamous December 2023 jet extension where we roasted for the rest of the month 

There is no warmup mid December.  Where are you getting that info from ? The warmups in the long range have been fake so far.

[BlizzardWx]

I was thinking some more about the question of where do you want to focus on for the VP. I assume the ITCZ location is the main driver of that, which obviously varies a lot and isn't always +/- 5 degrees. The map I posted earlier kind of shows this too with much of the stronger forcing south of the equator near the MC.

 

I'm also thinking more about the idea of the raw VP vs anomalies. Since the water is always warmest near the MC isn't having a standing wave there in the raw the climatology we would always expect? Like doesn't that almost always exist? And anomalies might be more useful because they show the deviations from that standing wave? I don't know, just thinking a lot this morning

If you use the equator to 10S band it looks MC focused the next week, then becoming more incoherent. 

[brooklynwx99]

3 minutes ago, BlizzardWx said:

I was thinking some more about the question of where do you want to focus on for the VP. I assume the ITCZ location is the main driver of that, which obviously varies a lot and isn't always +/- 5 degrees. The map I posted earlier kind of shows this too with much of the stronger forcing south of the equator near the MC.

 

I'm also thinking more about the idea of the raw VP vs anomalies. Since the water is always warmest near the MC isn't having a standing wave there in the raw the climatology we would always expect? Like doesn't that almost always exist? And anomalies might be more useful because they show the deviations from that standing wave? I don't know, just thinking a lot this morning

If you use the equator to 10S band it looks MC focused the next week, then becoming more incoherent. 

yeah, the anomalies are always more useful

[EasternLI]

17 minutes ago, BlizzardWx said:

 

I'm also thinking more about the idea of the raw VP vs anomalies. Since the water is always warmest near the MC isn't having a standing wave there in the raw the climatology we would always expect? Like doesn't that almost always exist? And anomalies might be more useful because they show the deviations from that standing wave? I don't know, just thinking a lot this morning
 

Was just about to make a post regarding that. Yes, It's exactly for that reason that the anomaly charts should always be used and the reason they are the ones always referenced. For instance, you could take a year such as 2009-10. Very well known as a modoki el nino year. Well if you look at the raw velocity potential, one could say strong forcing stuck at the MC. While the anomalies will paint a different picture entirely.

 

 

 

[GaWx]

2 hours ago, donsutherland1 said:

If the WPO relaxes from its forecast values of -2.000 or below, other teleconnections can gain influence over the pattern. The EPS currently forecasts an EPO+/AO+/PNA-/NAO+ regime toward the end of its run. If the WPO rises, that could allow ridging to expand across the CONUS with warmth following after a few days lag.

December 30-31, 1999:

The December 30-31, 1999 composite 500 mb map is one example of how unfavorable teleconnections overwhelmed a weaker WPO-. Then, the WPO was still impressive (below -1.000) but it was not at the extreme values necessary to overwhelm the pattern.

Milder conditions rapidly spread into the East.  Despite much above normal temperatures to start January 2000, the month wound up colder than normal. Late January (January 24-27 timeframe) saw a major snowstorm in the Southeast and lower Mid-Atlantic region.

For now, it looks to remain generally colder than normal through around December 20th. Nothing is cast in stone for the remainder of the month, though some temporary relaxation is plausible. IMO, the odds remain against a complete breakdown of the pattern and the onset of a sustained warm pattern during the closing 10-11 days of December. Still, it's worth watching the evolution of the guidance.

I suspect that there could be an increased risk of a pattern breakdown after mid-January, which often happens during La Niña winters, but that's in the speculative range right now. The PNA could play a larger role in how January evolves.

 Regarding the Januaries overall in the NE US following the last 11 -ENSO -PNA Decembers, only 2 were mild (2017 and 2023) while 3 were within a few degrees of normal and 6 were cold (1984, 1985, 2009, 2011, 2014, and 2022). So, 3 times as many mild were cold.

*Edited for correction: 6 Jans were cold, not just 5.

[PhiEaglesfan712]

30 minutes ago, MJO812 said:

There is no warmup mid December.  Where are you getting that info from ? The warmups in the long range have been fake so far.

Definitely agree with that. Plus, December 2023 was warm all the way through. Kind of like 2015 and 2021. All of those years had a regression to the mean in January, with snow and near normal temperature departures.

This year we have a cold December so far. We just need a snowfall, or otherwise, we might have a similar situation to December 2022.

[GaWx]

54 minutes ago, PhiEaglesfan712 said:

Definitely agree with that. Plus, December 2023 was warm all the way through. Kind of like 2015 and 2021. All of those years had a regression to the mean in January, with snow and near normal temperature departures.

This year we have a cold December so far. We just need a snowfall, or otherwise, we might have a similar situation to December 2022.

 I’m not using Dec 2022 as a heavily weighted analog because of snowcover. On this date in 2022, there was only 1% snowcover in the Midwest:

Compare that to today’s 46%, the 3rd highest only to 2013’s and 2007’s 53% and just ahead of 2005’s 45%. The 2003-24 average is only ~15% meaning today’s is ~3 times the average for Dec 7th:

@donsutherland1you may want to keep this in mind for your forecasts.
 

https://www.nohrsc.noaa.gov/nsa/index.html?region=Midwest&year=2025&month=12&day=7&units=e