Winter 2025-26

[Bob Chill]

3 hours ago, Ji said:

storms are the biggest crapshoot but without cold--it wouldnt matter. one thing that i hate about ninas is that we need phasing typically to get something good and we suck at phasing at the right time. usually very little gulf action 

So far it looks like the "nina" is weak sauce so I'm not really expecting classic nina climo dominating door to door. I think other variables like the ao/epo/nao will have more influence on our sensible wx and I wouldn't be surprised if there is split flow at times. Im really liking early ao/nao signs right now. 

I'm still feeling mediocre about snowfall but that comes with the territory and we're pretty much always northern stream dominant in all enso phases except for ninos.  However, get a -2sd ao/nao going and it opens the door for a hybrid storm that passes underneath us. Those can work here but not without anomalous blocking. Its been so long since we've had an extended blocking period that we all expect it to not happen lol but I'm feeling unusually optimistic about it until further notice 

[Stormchaserchuck1]

Yeah, the Nina is weak sauce right now. Going back to June 2023, 21/29 months have been +PNA (CPC). It's surprising because we've had 2 "most negative monthly PDO on record" periods during that time, and the last 15 months have been cool ENSO.. but tracking 500mb all the time, the -PNA tendency has not been the same since the 23-24 Strong Nino -- it was happening all the time before then, now it's not sustaining more than a short period of time. It would have to kind of come out of nowhere to be a -PNA Winter this year, possible, but not as likely as the 2017-2023 period. 

Precip is definitely not a El Nino STJ right now, but I don't see why we can't have storms track across the Tenn valley and then into the Mid Atlantic this Winter. I think there is a -AO tendency with negative SLP 60-90N over the warm season (strong Summer -> Winter correlation since 2012) this year. Lots of cold H5 across the N. Hemisphere this year too, including the lowest 500mb reading on record for August this last August. 2020-2023 was not cold at H5 in the Northern Hemisphere at all. The strongest leading correlation I've found to Winter cold/snow is preceding year total H5 cold across the N. Hemisphere. 

[bncho]

it seems like we've narrowed in closer towards a more unified consensus. two questions: is a dead ratter like 22-23 off the table, and is the ceiling higher than 24-25?

[Stormchaserchuck1]

16 minutes ago, bncho said:

it seems like we've narrowed in closer towards a more unified consensus. two questions: is a dead ratter like 22-23 off the table, and is the ceiling higher than 24-25?

24-25 was the coldest Winter since 14-15. Something similar to last year is possible this year, as lot of the same conditions are reoccurring. 

We had 2 favorable patterns in 22-23, in December and March. 6/7 times out of 10, those patterns would deliver a SECS. It just didn't happen that way that year - a repeat of 22-23 though may not be as bad as you would think. Jan and Feb were really warm that Winter though: +QBO coupled with La Nina to have a strong 10mb vortex in 22-23.. we have a -QBO this Winter, and the long range Euro ensembles are already looking like they want to do a Stratosphere warming in a few weeks (which would correlate with -AO late Dec into early Jan (about 70% likely)). 

[frd]

This would not at all surprise me that December is cold but with below normal snowfall. 

 

Ben Noll

 

@BenNollWeather

1h

 

 

There are signs that December is going to be particularly chilly this year, but does that mean it's also going to be snowy? It depends where you live. In past years with similar climate characteristics to this year, northern states had the highest odds for above-average snowfall during December. Using history as a guide, regions such as New England, the Great Lakes, Midwest, northern Plains and Intermountain West are favored to be snowier-than-average next month. The Northeast, including the big cities, is more of a question mark and could go either way. The Southeast and Mid-Atlantic might lack moisture, reducing the odds for snow storms.

[BTRWx's Thanks Giving]

Don't ignore the northeast Pacific. I think this winter could easily bust. Remember this?

[frd]

Latest  ECMWF update regarding the 45 day 60 degree N Zonal Mean 10mb Wind Forecast. Of note, the ensemble average in this update is slighter higher than the previous ensemble forecast, however, still bullish for a weak PV.   

 

[frd]

From Paul Roundy, this shows - NAO and Greenland blocking might be a frequent player during the upcoming winter. 

 

 

 

[Daniel Boone]

On 11/8/2025 at 10:47 AM, frd said:

This would not at all surprise me that December is cold but with below normal snowfall. 

 

Ben Noll

 

@BenNollWeather

1h

 

 

There are signs that December is going to be particularly chilly this year, but does that mean it's also going to be snowy? It depends where you live. In past years with similar climate characteristics to this year, northern states had the highest odds for above-average snowfall during December. Using history as a guide, regions such as New England, the Great Lakes, Midwest, northern Plains and Intermountain West are favored to be snowier-than-average next month. The Northeast, including the big cities, is more of a question mark and could go either way. The Southeast and Mid-Atlantic might lack moisture, reducing the odds for snow storms.

If formidable blocking is realized, it should be above average Snowfall. Had 2010-11 or 95-96 not had that ACE Snowfall would have undoubtedly been much less. 

[Bob Chill]

Current CFS Jan h5 is a good visual of what I recently posted irt split flow+blocking during a "Nina". This is a sweet looking prog.... 

[mitchnick]

3 hours ago, Bob Chill said:

Current CFS Jan h5 is a good visual of what I recently posted irt split flow+blocking during a "Nina". This is a sweet looking prog.... 

Looks very close to the January Eps seasonal that came out a few days ago.

[Bob Chill]

28 minutes ago, mitchnick said:

Looks very close to the January Eps seasonal that came out a few days away.

Unless I'm forgetting something in between, we haven't had a legit lasting HL blocking period with a real -NAO since Jan 2011. We really are due for one

[psuhoffman]

2 hours ago, Bob Chill said:

Unless I'm forgetting something in between, we haven't had a legit lasting HL blocking period with a real -NAO since Jan 2011. We really are due for one

Jan to Feb 2016 was a legit blocking regime. Shame we only cashed in once but it was a big one at least. 

March 2018 but dunno if March counts 

But we had great blocking from mid December to early Feb 2021.  It produced a great winter up here but nothing but perfect track rainstorms for DC that winter.  That was one of the more depressing seasons in terms of wondering how much damage to DCs snow climo warming has had.  No excuse for a single digit snow season with this h5 for the heart of winter! 

 

[Stormchaserchuck1]

I would say that 15-16 one was -AO. It actually doesn't help us much when the mean ridge is at 90N.. that puts a mean trough at 45N.. there was some ridging that extended down the Davis Strait though. 

Since 2013, 19/19 Winter months with NAO value >1.12 have all been positive (CPC)! 83% of the Winter months have had +NAO since 11-12, and we only had 1 average negative NAO Winter in that time.. which was 20-21, but that only came out to -0.12/month. but that was our lowest NAO Winter since 10-11. 

We've had NAO blocks during that time, but they usually don't last more than 10-15 days. 

[Stormchaserchuck1]

12 hours ago, frd said:

From Paul Roundy, this shows - NAO and Greenland blocking might be a frequent player during the upcoming winter. 

What's a 100-day Lowpass Constructed Analog? 

[Stormchaserchuck1]

3 hours ago, Bob Chill said:

Current CFS Jan h5 is a good visual of what I recently posted irt split flow+blocking during a "Nina". This is a sweet looking prog.... 

Since 2012 there has been a really strong correlation between Summer SLP, and negative SLP anomaly 60-90N and the following Winter having a ridge at 90N. It has worked almost every single time, almost a 0.70, or 85% correlation. Doesn't work as well before 2012, but we had that pattern strongly this year so it's no surprise so many seasonal models are popping a Winter anomaly ridge at 90N. 

[Stormchaserchuck1]

On 11/8/2025 at 12:02 PM, BTRWx's Thanks Giving said:

Don't ignore the northeast Pacific. I think this winter could easily bust. Remember this?

Can you elaborate on what you mean? Bust warm or bust cold? What's going on in 11-12 in the NE Pacific? 

[frd]

6 minutes ago, Stormchaserchuck1 said:

What's a 100-day Lowpass Constructed Analog? 

 

 

 

 

 

 

Paul Roundy

 

@PaulRoundy1

·

13h

 

 

The algorithm is based entirely on outgoing longwave radiation data in the tropics. The OLR diagnostic algorithm is explained and assessed here: https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/qj.962 And the association with the extratropical circulation is diagnosed through the method of constructed analogs: https://journals.ametsoc.org/view/journals/mwre/141/7/mwr-d-12-00223.1.xml Since the algorithm does not include any explicit information about the ocean (it includes what is implicit in OLR anomalies), and since the OLR signal is projected forward based on how similar OLR signals moved in the past, it will do poorly when the ocean subsurface is undergoing strong changes. In the short term (e.g., next 2 months), the results are reasonable, but in this particular event, there is risk of El Niño being forced by strong subseasonal variability (February through May). Should that occur, the verification data would diverge from the forecast.

[Stormchaserchuck1]

^Ok, I've plotted Tropical OLR and found that subsurface temperature anomalies near the thermocline (associated with sea level height) are actually more impactful. You see the correlation increase to almost double and the same goes for vs 850mb wind, 250mb wind, sea-level pressure. 

Matching Tropical Pacific OLR though, which is "Weak La Nina-like" right now, comes out to a -NAO in Nov and Dec then switches to +NAO for Jan and Feb. Curious how he got -NAO for Jan and Feb. 

[Terpeast]

With a SSW/weak PV being forecast this month, I checked when the last time we had a SSW in November. 1968. 

So I looked up the 1968-69 analog, and most of the teleconnections match. -QBO, -PDO, +AMO, etc... except it was a weak nino, not a nina. 

It was a very cold winter, averaging roughly -5 through DJFM, snowfall was backloaded apart from an early November snow. 

With this winter being a weak nina, snow might be more front-loaded and may be colder than what seasonal models are depicting, assuming the SSW verifies. 

[nw baltimore wx]

[Eskimo Joe]

27 minutes ago, Terpeast said:

With a SSW/weak PV being forecast this month, I checked when the last time we had a SSW in November. 1968. 

So I looked up the 1968-69 analog, and most of the teleconnections match. -QBO, -PDO, +AMO, etc... except it was a weak nino, not a nina. 

It was a very cold winter, averaging roughly -5 through DJFM, snowfall was backloaded apart from an early November snow. 

With this winter being a weak nina, snow might be more front-loaded and may be colder than what seasonal models are depicting, assuming the SSW verifies. 

We're so due for a legit winter. I hope we get a White Christmas. Just a solid 3" - 5" event that sticks around for a bit. That's all I'm asking.

[Maestrobjwa]

1 hour ago, Terpeast said:

With a SSW/weak PV being forecast this month, I checked when the last time we had a SSW in November. 1968. 

So I looked up the 1968-69 analog, and most of the teleconnections match. -QBO, -PDO, +AMO, etc... except it was a weak nino, not a nina. 

It was a very cold winter, averaging roughly -5 through DJFM, snowfall was backloaded apart from an early November snow. 

With this winter being a weak nina, snow might be more front-loaded and may be colder than what seasonal models are depicting, assuming the SSW verifies. 

Now with these SSWs...like, how difficult are they to forecast even a week out? And if they do happen are we able to see it in real time? I ask because it feels like there have been a lot of wild goose chases over the last decade or so!

[WxUSAF]

11 minutes ago, Maestrobjwa said:

Now with these SSWs...like, how difficult are they to forecast even a week out? And if they do happen are we able to see it in real time? I ask because it feels like there have been a lot of wild goose chases over the last decade or so!

The stratosphere is much more predictable than the troposphere, so the long range ensembles do have “skill” beyond the typical 8-10 day sensible weather prediction limit. I want to say there is skill to 30-40 days?? It seems guidance often tries to predict these strat warming events a little too quickly and there are can kicks, but that’s my anecdotal observation.

[bncho]

1 hour ago, Eskimo Joe said:

We're so due for a legit winter. I hope we get a White Christmas. Just a solid 3" - 5" event that sticks around for a bit. That's all I'm asking.

I would argue that last year was a legit winter, just a bit lacking in the snow department.

[bncho]

2 hours ago, Terpeast said:

With a SSW/weak PV being forecast this month, I checked when the last time we had a SSW in November. 1968. 

So I looked up the 1968-69 analog, and most of the teleconnections match. -QBO, -PDO, +AMO, etc... except it was a weak nino, not a nina. 

It was a very cold winter, averaging roughly -5 through DJFM, snowfall was backloaded apart from an early November snow. 

With this winter being a weak nina, snow might be more front-loaded and may be colder than what seasonal models are depicting, assuming the SSW verifies. 

Two questions: 
The snowfall that winter wasn't that impressive.

1. Is this because it was too cold?

2. If it was because it was too cold, would we see more snow in the modern climate?

[Eskimo Joe]

On 11/7/2025 at 7:49 PM, bncho said:

it seems like we've narrowed in closer towards a more unified consensus. two questions: is a dead ratter like 22-23 off the table, and is the ceiling higher than 24-25?

IMO, we'll know for sure by Christmas. If all the hopes, prognostications, and predictions of December coming in cold, and potentially snowy, end as a mirage or just a "kicking the can pattern" then we know we're in for a miserable winter.

[Terpeast]

2 hours ago, bncho said:

Two questions: 
The snowfall that winter wasn't that impressive.

1. Is this because it was too cold?

2. If it was because it was too cold, would we see more snow in the modern climate?

That winter, particularly February, was notable because of a huge noreaster from NJ north, and Mt Washington got 49" in 24 hours, or a total of 91" over 3 days. See 100 hour snowstorm: The 100-Hour Snowstorm of February 1969 | NOAA Climate.gov

Another one just before that hit western NC and northern SC with up to 2 feet. There was a thread about it on this very forum: February 1969 Foothills/Piedmont Deep Snowstorm - Southeastern States - American Weather

There was almost no noteworthy events for Dec and Jan. With strong greenland blocking and a strong aleutian ridge, it was probably cold and dry along the SE and east, much like a modern La Nina pattern we've been seeing over the last several years - only colder. In a modern climate, probably little or no snow, just a few degrees warmer.

Then in Feb, a ridge began to build over the rockies while the greenland block continued, and then those two big storms happened.