2025-2026 ENSO

[MJO812]

29 minutes ago, snowman19 said:

While I’m certainly on board with January being another colder than normal month in the east, due to the front-loaded Niña we are in, which would fit the progression, that’s where I think it stops. At least that’s my thought right now. I’m not sure what BAMWX thinks about February and March? I know there’s some hype on twitter today about the new CFS being very cold in the east for the next 3 months; Jan, Feb and Mar….I just don’t see that happening. We haven’t seen a La Niña accomplish that (all 5 months in a row; Nov, Dec, Jan, Feb, Mar) being below normal cold in over 30 years (1995-96). That was a very atypical Niña, coming off an El Niño with a strong +PDO all winter long. As I said before, the only way I could possibly see that happening would be with a big, anomalous stratospheric shakeup like 2018 had. I guess we’ll see over the next few weeks

Bam is above normal for February 

[GaWx]

On 12/27/2025 at 10:54 PM, GaWx said:

  I’ve been quite curious about what phases the MJO would be in during the heart of the widespread historic US warmth of late Dec, Dec 23-27. We needed to wait due to several days of reporting lag. Would any of it be in the typically chilly in the E 1/2 of the US phase 8? 

 Well, now we have the answer for the first 3 days, Dec 23-25: not surprisingly, none of those first 3 days were in phase 8. It turns out that Dec 23-4 were in very weak phase 7 while Dec 25 was in very weak phase 6, which I consider intuitive:

 

2025          12          23 -0.28945175      0.37228486               7  0.47157007      Gottschalk10_method:_OLR_&_ACCESS_wind      
        2025          12          24 -0.12800699      0.45807526               7  0.47562456      Gottschalk10_method:_OLR_&_ACCESS_wind      
        2025          12          25  0.16766728      0.36077648               6  0.39783412      Gottschalk10_method:_OLR_&_ACCESS_wind

 

 Based on a combo of the above diagram and a related adjustment to the model prog consensus, I’m predicting that Dec 26th will be in very weak 4 and Dec 27th will be in either weak 3 or weak 2.

 Will we get back into phase 8 before the end of Dec? The GEFS, JMA, and CFS with my adjustments suggest likely not whereas the adjusted Euro suggests there’s a chance for at least one day of weak 8 then.

 Will we get back into phase 8 in early Jan? As of now there’s a moderate chance of mainly a weak 8, but that’s all I can say right now due to model disagreement and it being too far out for a confident prediction.

 Followup: The full torch period MJO is now in as I had to wait for the reporting lag. It turns out that the MJO during the heart of the torch (12/23-27) wasn’t in a typically cold track after all. Instead of a typically cold in Dec counterclockwise track of 8-1-2 of moderate to weak amp (including near or inside circle left side), it tracked clockwise weak 7-6-4-3, an unusual Dec track that one would not associate with cold as it kind of went in reverse and in typically not cold phases even though they were weak:

 

2025          12          23 -0.28945175      0.37228486               7  0.47157007      Gottschalk10_method:_OLR_&_ACCESS_wind      
        2025          12          24 -0.12800699      0.45807526               7  0.47562456      Gottschalk10_method:_OLR_&_ACCESS_wind      
        2025          12          25  0.16766728      0.36077648               6  0.39783412      Gottschalk10_method:_OLR_&_ACCESS_wind      
        2025          12          26  0.17544751     -6.13679737E-02           4  0.18587054      Gottschalk10_method:_OLR_&_ACCESS_wind      
        2025          12          27  4.42237742E-02 -0.35203809               3  0.35480496

[Krs4Lfe]

44 minutes ago, snowman19 said:

While I’m certainly on board with January being another colder than normal month in the east, due to the front-loaded Niña we are in, which would fit the progression, that’s where I think it stops. At least that’s my thought right now. I’m not sure what BAMWX thinks about February and March? I know there’s some hype on twitter today about the new CFS being very cold in the east for the next 3 months; Jan, Feb and Mar….I just don’t see that happening. We haven’t seen a La Niña accomplish that (all 5 months in a row; Nov, Dec, Jan, Feb, Mar) being below normal cold in over 30 years (1995-96). That was a very atypical Niña, coming off an El Niño with a strong +PDO all winter long. As I said before, the only way I could possibly see that happening would be with a big, anomalous stratospheric shakeup like 2018 had. I guess we’ll see over the next few weeks

This sounds accurate. La Ninas are usually warmer than normal in February and torch in March. December and January are the best months for snowfall in a La Nina. Once you punt January (not saying we are, at least not yet) in a La Nina, you run into significant trouble for rest of winter. Now would be the month to cash in. In a La Nina, anything past end of January becomes more difficult. 

[GaWx]

 Looking ahead MJOwise, I hope today’s GEFS forecast doesn’t verify as it has it going into a strengthening 6 as we approach mid Jan:

Phase 6 in Jan is one of the warm E US phases along with 4-5. Say it ain’t so, GEFS! Of course, even if it verifies, the warmth is just based on the average and it can still end up cold.

 

The EPS is better but not great as it heads into a weak 7, which is pretty neutral. I’d much prefer to see 8-1-2 for the best shot at a cold E US pattern:

 

[GaWx]

 I’m calculating that the Dec NAO will come in near -1, easily the most negative Dec since 2010. This is the first moderate to strong Dec -NAO during active Dec sunspots since 2002, when sunspots were 135. I’m estimating Dec of 2025 SSN to be 120.

[GaWx]

 This was released by BAMwx:

 

 Thoughts? I’m going to need to research this myself to feel comfy with BAMwx’s idea of the highly counterintuitive idea of a very cold E US on average during La Niña (-AAM) Jan phase 6 periods. They’re saying this probably because GEFS is forecasting phase 6 going into mid-Jan as per my earlier MJO forecast post. I can do the analysis but it will take time. I’m planning to look at actual temp anoms for a city like ATL, Chat., Nashville, or GSP that’s in the heart of the coldest (pink) for all phase 6 days during Jan since 1975. Actually anyone can do it but one needs lots of time to do this.

In the meantime, I’ll continue to root for weak to moderate 8-1-2 over 6 or even 7.

@donsutherland1@bluewave

[Krs4Lfe]

CPC just came in with crushing news for snow weenies across most of the US. Warm and mild, only colder pockets here in the northeast. Looks like pushing the ridge out over Central US was just temporary. Most of CONUS goes right back to warmer temperatures and that forecast is for 1/8-1/13. Most will have to punt first half of January. Never a good sign imo 

[EasternLI]

Seems to be a big question mark in the 8-10 day range in the EPS guidance today. Regarding the NAO block and what ultimately happens with that now. Not surprising, but it is important. Some guidance such as the 12z OP Euro from today. Want to send a rather inconspicuous little cannonball of energy from the ULL through that block which breaks it down. Sometime around day 6-7. Which would be probably the most unceremonious way possible to get it to end. We'd likely see the ridge roll into the east and then wait for the changes in the Pacific during a much milder period. But then you have the 12z EPS for the 8-10 day period. Which seems quite against that idea and apparently favors keeping the blocking instead. Which would keep the coastal track storm chances in play. As per the leading EPS cluster scenario. Or even the 2nd one. The OP Euro idea is included in the minority cluster number 3. The least favored outcome. Maybe tomorrow offers a clearer picture but it's interesting to see the OP run with a minority of support in the ensemble today though.

 

[MJO812]

49 minutes ago, Krs4Lfe said:

CPC just came in with crushing news for snow weenies across most of the US. Warm and mild, only colder pockets here in the northeast. Looks like pushing the ridge out over Central US was just temporary. Most of CONUS goes right back to warmer temperatures and that forecast is for 1/8-1/13. Most will have to punt first half of January. Never a good sign imo 

Shocking

[cny rider]

3 hours ago, GaWx said:

 Looking ahead MJOwise, I hope today’s GEFS forecast doesn’t verify as it has it going into a strengthening 6 as we approach mid Jan:

Phase 6 in Jan is one of the warm E US phases along with 4-5. Say it ain’t so, GEFS! Of course, even if it verifies, the warmth is just based on the average and it can still end up cold.

 

The EPS is better but not great as it heads into a weak 7, which is pretty neutral. I’d much prefer to see 8-1-2 for the best shot at a cold E US pattern:

 

Perhaps I'm reading this wrong but the chart with T composites for the different MJO phases seems to suggest there is zero significance to phase 6 regarding temperature for the eastern US.

Am I interpreting it correctly to mean it has no prognostic significance for DJF temperatures in the east?

 

[GaWx]

6 minutes ago, cny rider said:

Perhaps I'm reading this wrong but the chart with T composites for the different MJO phases seems to suggest there is zero significance to phase 6 regarding temperature for the eastern US.

Am I interpreting it correctly to mean it has no prognostic significance for DJF temperatures in the east?

 

Actually, I think it’s the opposite because the strongest warm anomalies are in the E US though admittedly I don’t know why it shows that as “0-2.5% significance”. That doesn’t make any sense as it should be the opposite!

[cny rider]

2 minutes ago, GaWx said:

Actually, I think it’s the opposite because the strongest warm anomalies are in the E US though admittedly I don’t know why it shows that as “0-2.5% significance”. That doesn’t make any sense as it should be the opposite!

Thank you for responding.  I can't make sense of it either.

 

[Terpeast]

1 hour ago, GaWx said:

Actually, I think it’s the opposite because the strongest warm anomalies are in the E US though admittedly I don’t know why it shows that as “0-2.5% significance”. That doesn’t make any sense as it should be the opposite!

It’s a statistics term that doesn’t mean what the layperson thinks it does. In statistics, significance on a correlation plot doesn’t necessarily mean the relationship between two variables is strong or important. A significance of <5% means a p-value of <0.05 (>95% confidence level), not that the correlation is strong. Two different things.

[GaWx]

17 minutes ago, Terpeast said:

It’s a statistics term that doesn’t mean what the layperson thinks it does. In statistics, significance on a correlation plot doesn’t necessarily mean the relationship between two variables is strong or important. A significance of <5% means a p-value of <0.05 (o >95% confidence level), not that the correlation is strong. Two different things.

Thanks for clarifying for us. My bad for misunderstanding what they meant by “0-2.5% significance”. So, it sounds like they’re saying that the chance that the warmth in the E US is due to randomness is only 2.5% or lower. Do I have that right? That would make perfect sense and sort of jibes with @cny riderand my original thinking.

[Terpeast]

16 minutes ago, GaWx said:

Thanks for clarifying for us. My bad for misunderstanding what they meant by “0-2.5% significance”. So, it sounds like they’re saying that the chance that the warmth in the E US is due to randomness is only 2.5% or lower. Do I have that right? That would make perfect sense and sort of jibes with @cny riderand my original thinking.

Yes thats right, but it doesn’t mean phase 6 automatically means warm in the east. Usually when amplitude is strong, which isn’t the case now. Weak/cod 6 during -enso/-aam usually means cold in the east, but not always. 

[GaWx]

6 hours ago, GaWx said:

 This was released by BAMwx:

 

 Thoughts? I’m going to need to research this myself to feel comfy with BAMwx’s idea of the highly counterintuitive idea of a very cold E US on average during La Niña (-AAM) Jan phase 6 periods. They’re saying this probably because GEFS is forecasting phase 6 going into mid-Jan as per my earlier MJO forecast post. I can do the analysis but it will take time. I’m planning to look at actual temp anoms for a city like ATL, Chat., Nashville, or GSP that’s in the heart of the coldest (pink) for all phase 6 days during Jan since 1975. Actually anyone can do it but one needs lots of time to do this.

In the meantime, I’ll continue to root for weak to moderate 8-1-2 over 6 or even 7.

@donsutherland1@bluewave

I did the analysis of the 15 Jans with  phase 6 during La Niña (1975-2025)

Year….# phase 6 days…avg anomaly

1975…3…-8

1976…13…-9

1989…3…+8

1999…3…+2

2000…3…-4

2006…6…+3

2008…3…+8

2009…6…+1

2011…12…-7

2012…19…+1

2017…2…0

2018…3…-2

2021…8…-1

2022…4…-9

2025…2…-5

—————
91 total days that averaged ~-2 

3 MBN

3 BN

6 NN

1 AN

2 MAN

 BAMwx said that the phase 6 MJO/-AAM analogs had this at ~-6 to -7. So, I believe based on the above analysis that this is a good bit overdone and should be ~-2. Granted, it came in cool on average with the -2 anomaly, which to me is admittedly a bit counterintuitive. And 1975, 1976, 2011, and 2022 came in quite cold during their Jan phase 6 days showing it would be doable. But one can see that only 6 of the 15 (40%) Jans during phase 6 were in BAMwx’s cold vicinity.

 So, I’d still much rather it go 8-1-2.

 Any comments?

@donsutherland1@bluewave

[GaWx]

Watch out for potential major Arctic plunges week of 1/19-26: this was released on Tue 12/30.

Exclusive Weather Updates from Vaisala/X Weather & The Weather Co.

Brad Harvey, senior operational meteorologist at Vaisala, says that the forecast for the 6-to 10-day period features much-above-normal temperatures from the West to Texas. Highs are forecast to reach the 50s in Denver, 60s-70s in Dallas, and 70s in Houston. The Midwest and East are forecast to be drier than normal thanks to rounds of high pressure migrating southward from Canada. The forecast is near normal for temperatures in the Upper Midwest and below normal in the East. Risks are mixed for the Upper Midwest, where our forecast takes the middle ground between the warmer GFS and colder ECMWF solutions. Meanwhile, warmer risks in the Rockies are associated with downslope flow, while the Great Basin could be colder under high pressure. The models have lacked consistency in both the 6-to 10-day and 11-to 15-day periods. “The GFS EN projects a –PNA pattern, while ECMWF trends toward a +PNA. Neither of these solutions are given higher favorability, with our forecast featuring a round of above normal temperatures in the Eastern Half and belows emerging late in the Midwest.” For more information, go to https://www.xweather.com/weatherdesk.

Mickey Shuman, a senior meteorologist with The Weather Company, tells us that for most of next week, the Pacific pattern will reverse, helping to drive mild Pacific air into much of western and interior North America. However, a west-based -NAO block will impede the advancement of the mild air into the East. By the 11-to 15-day period, mild Pacific and maritime Atlantic air will overspread the entirety of Canada, essentially shutting down the risk of any major cold air intrusions, such that most of the CONUS moderates and ends up on the warmer side of normal, supporting a prolonged stretch of lower-than-normal GWHDDs. That being said, an emerging +PNA signal also suggests that there won’t be a major or sustainable warm-up and that some seasonably cold air attempts to expand south and east later in the period. The bigger story is the potential pattern change for the middle to end of the month, which could lead to noteworthy cold Arctic blasts over the eastern two-thirds centered on the week of the 19-26th. For more information, go to https://www.weathercompany.com/

[snowman19]

19 hours ago, 40/70 Benchmark said:

Mid January I think that will change...

It’s starting to look like a +TNH develops maybe just after we pass mid-January into late January. The caveat with +TNH patterns is that they are also correlated with +AO (+NAM), +NAO and a healthy SE ridge. So, while certainly arctic cold, it’s not going to be a “KU” pattern with ‘big dog’ snowstorms up the I-95 corridor, DC-BOS as some folks on twitter are saying….

[bluewave]

On 12/30/2025 at 7:44 AM, 40/70 Benchmark said:

I had 1981 and 1996 in my composite...

Great job. For some reason, this type of pattern has preceded or accompanied El Niño development. So it will be interesting to see how things go since this has been the most amplified version of the pattern we have seen in December. 

Less amplified versions of this December pattern

1996…..1997-1998 super El Nino

1981……1982-1983 super El Niño 

1980….weak El Nino

1977…..weak El Niño 

1958…..strong El Niño winter before 

1957…..strong El Niño 

 

[snowman19]

31 minutes ago, snowman19 said:

It’s starting to look like a +TNH develops maybe just after we pass mid-January into late January. The caveat with +TNH patterns is that they are also correlated with +AO (+NAM), +NAO and a healthy SE ridge. So, while certainly arctic cold, it’s not going to be a “KU” pattern with ‘big dog’ snowstorms up the I-95 corridor, DC-BOS as some folks on twitter are saying….

To add to this, IF said +TNH pattern (-EPO/+AO/+NAO/SE ridge) develops just after mid-month into late January, it would argue for overrunning events and SWFEs. The question then becomes does it favor New England? Or PHL/NYC north into New England? 

[Krs4Lfe]

23 minutes ago, snowman19 said:

It’s starting to look like a +TNH develops maybe just after we pass mid-January into late January. The caveat with +TNH patterns is that they are also correlated with +AO (+NAM), +NAO and a healthy SE ridge. So, while certainly arctic cold, it’s not going to be a “KU” pattern with ‘big dog’ snowstorms up the I-95 corridor, DC-BOS as some folks on twitter are saying….

Agreed. Right now the south East Ridge has been pushed back quite a bit so any storm that comes towards our area would likely not be interfered by that ridge and we would not run the risk of the storm being amplified too much and cutting to our west. Instead, our current problem is that we don’t have enough amplification because the northern stream is just flowing too fast and cannot phase with the southern stream in time to lead to a large coastal storm. However, it looks to be towards mid month that there is a shake up in the Pacific, which will push the mild air in the west and central US over the east US  briefly. Then afterwards we will appear to be in a more of a colder regime similar to what we are in now but this time the cold will be more widespread across the US. While that will likely increase the chances for snow because our snow storms will have already been formed to our west and traverse across the US, we do run the risk of a larger southeast Ridge, which would lead to potential over amplification and temperature issues during those storms. So for now, we have the cold, but we don’t have the snow, and in a few weeks it’s looking like we might have the cold, but we have issues with the southeast Ridge, which will of course affect our chances for snow as well. Either way, we need a big shake up in the Pacific because most of the US is snapping back to warm and dry for the foreseeable future, which doesn’t go well for our chances either.

[LakePaste25]

1 hour ago, snowman19 said:

It’s starting to look like a +TNH develops maybe just after we pass mid-January into late January. The caveat with +TNH patterns is that they are also correlated with +AO (+NAM), +NAO and a healthy SE ridge. So, while certainly arctic cold, it’s not going to be a “KU” pattern with ‘big dog’ snowstorms up the I-95 corridor, DC-BOS as some folks on twitter are saying….

I agree that pattern generally does not support sustained blocking. That said, I wouldn’t rule out an opportunity while that pattern settles in and while the blocking decays. 

[GaWx]

 Natural gas, which usually drops when the high pop. centers of the NE US and Midwest look warmer in the 2 week forecast, is down >4%.

 The forecasted -EPO/+TNH cold pattern for the central US eventually looks great for cold domination prospects for the central US, much of the Midwest, and the N NE. But the biggest risk against sustainable cold is in the SE primarily and Mid-Atlantic secondarily, where the SE ridge may be too strong if the PNA in the means doesn’t go positive. This is very difficult to forecast this far out.

 Although I don’t like the warmer model developments of recent days for week 2 in the E US, my hope is still that the PNA in the means will flip for Jan averaged out to match the 100% of -ENSO -PNA Decs since 1983-4 that went to a net +PNA for Jan. My other hope is that the 90 day -PNA bias of the GEFS/EPS/GEPS means that they’re currently off.

The GEFS AO looks better for midmonth vs yesterday fwiw:

Yesterday:

 

Today:

[snowman19]

10 minutes ago, GaWx said:

 Natural gas, which usually drops when the high pop. centers of the NE US and Midwest look warmer in the 2 week forecast, is down >4%.

 The forecasted -EPO/+TNH cold pattern for the central US eventually looks great for cold domination prospects for the central US, much of the Midwest, and the N NE. But the biggest risk against sustainable cold is in the SE primarily and Mid-Atlantic secondarily, where the SE ridge may be too strong if the PNA in the means doesn’t go positive. This is very difficult to forecast this far out.

 Although I don’t like the warmer model developments of recent days for week 2 in the E US, my hope is still that the PNA in the means will flip for Jan averaged out to match the 100% of -ENSO -PNA Decs that went to a net +PNA for Jan. My other hope is that the 90 day -PNA bias of the GEFS/EPS/GEPS means that they’re currently off.

The GEFS AO looks better for midmonth vs yesterday fwiw:

Yesterday:

 
Today:

Therein lies the risk if we do in fact see a +TNH pattern take over just after mid-January….the AO (NAM). Here’s Eric’s new tweet on it, but +TNH favors the AO going positive along with the NAO going positive. And you already mentioned the SE ridge risk with it

 

 

 

 

[GaWx]

 Thanks, snowman.

 One of the favored analogs has been 2021-2. This was the GEFS PNA forecast 4 years ago today through Jan 14, 2022: it showed the PNA turning positive, which it did but the mean wasn’t positive enough for midmonth:

 

To compare, here’s today’s GEFS PNA forecast, which is clearly going in the right direction at the end but still isn’t then yet a +PNA. Note the wide spread of the members, however:

[GaWx]

 The model consensus is suggesting a good chance for the Jan MJO to stay inside the circle for 20+ days. Only the following Jans since 1975 were on or inside the circle for 20+ days (note that it’s been 23 years since the last one due to the MJO avg amp increasing):

1977, 1980, 1981, 1982, 1994, 1996, 2000, 2003

 Of these 8 Jans in the E US, 1977, 1981, 1982, 1994, and 2003 were cold while 1996 and 2000 were NN to slightly BN. Only 1980 was AN and it was only modestly AN. That one had its MJO the furthest right of the eight Jans mainly on or inside the circle with none in phases 7, 8, or 1. Of its 31 days, 25 were in phases 4 or 5.
 
 So, none of the 8 were anywhere near a torch.

 Here’s the cold composite for these 8 Jans with 20+ days on or inside the circle:

 

 Here’s the composite for the other Jans near the endpoints and in between: MJO outside circle 12+ days

[raindancewx]

My idea for December was a very cold and a very warm period - worked pretty well.

[GaWx]

On 12/27/2025 at 1:40 PM, GaWx said:

 I see ~no chance for Dec ‘25 to come in warmer than Dec ‘39’s 37.7. Through the 27th (last widespread US warm day), MTD could rise to ~38.2. But 12/28-31 are progged to avg ~31. That would bring the full Dec back down to ~37.2.

Bump for @TheClimateChanger

Do you have an update of Dec through the 30th? TIA

 I realize that with today still being colder than the avg of 12/1-30 by ~4 degrees per my guess, the final Dec update will be a little colder than 12/1-30.

[40/70 Benchmark]

7 hours ago, snowman19 said:

It’s starting to look like a +TNH develops maybe just after we pass mid-January into late January. The caveat with +TNH patterns is that they are also correlated with +AO (+NAM), +NAO and a healthy SE ridge. So, while certainly arctic cold, it’s not going to be a “KU” pattern with ‘big dog’ snowstorms up the I-95 corridor, DC-BOS as some folks on twitter are saying….

Eh...depends...worked out okay in January 2022 and January-February 2015.

[40/70 Benchmark]

5 hours ago, snowman19 said:

Therein lies the risk if we do in fact see a +TNH pattern take over just after mid-January….the AO (NAM). Here’s Eric’s new tweet on it, but +TNH favors the AO going positive along with the NAO going positive. And you already mentioned the SE ridge risk with it

 

 

 

 

My pre-season idea was for big +TNH to take over second half of January following a mid-month reflection event...this is also a great wave 2 precursor pattern for my forecast PV split in February.