Winter 2025-26

[bncho]

Is December looking less and less good (because it seems like the beginning of the month has trended warmer), or is it just models rushing the pattern change like usual?

[Stormchaserchuck1]

12 minutes ago, bncho said:

Is December looking less and less good (because it seems like the beginning of the month has trended warmer), or is it just models rushing the pattern change like usual?

The Pacific looks good with MJO going through Phase 7 and possibly Phase 8.. models are developing and have trended toward a +PNA pattern. The Atlantic was looking blocky earlier in the month and that was exciting because it was associated with a Stratosphere warming to help sustain the pattern until possibly early January. In the last few days a big +NAO appeared in the medium range, and the 10mb warmings doesn't look as strong, although it's still a Strat warming happening. We will probably get colder later in the month, but it kind of has a bad taste when the fundamentals were looking so good, now it's just a MJO-amped pattern and nothing more. By fundamentals I mean holding a -NAO for more than 10 days. 

[bncho]

7 minutes ago, Stormchaserchuck1 said:

The Pacific looks good with MJO going through Phase 7 and possibly Phase 8.. models are developing and have trended toward a +PNA pattern. The Atlantic was looking blocky earlier in the month and that was exciting because it was associated with a Stratosphere warming to help sustain the pattern until possibly early January. In the last few days a big +NAO appeared in the medium range, and the 10mb warmings doesn't look as strong, although it's still a Strat warming happening. We will probably get colder later in the month, but it kind of has a bad taste when the fundamentals were looking so good, now it's just a MJO-amped pattern and nothing more. 

Correct me if I'm wrong, but essentially what you're saying is that we’ll probably still get colder later in December, but the pattern is now looking less “textbook perfect” than it did before; it looks more like a pattern driven mainly by the MJO rather than a more powerful and sustained cold setup from both the Pacific and the Atlantic.

[frd]

7 minutes ago, Stormchaserchuck1 said:

The Pacific looks good with MJO going through Phase 7 and possibly Phase 8.. models are developing and have trended toward a +PNA pattern. The Atlantic was looking blocky earlier in the month and that was exciting because it was associated with a Stratosphere warming to help sustain the pattern until possibly early January. In the last few days a big +NAO appeared in the medium range, and the 10mb warmings doesn't look as strong, although it's still a Strat warming happening. We will probably get colder later in the month, but it kind of has a bad taste when the fundamentals were looking so good, now it's just a MJO-amped pattern and nothing more. 

Didn't Webb say the - NAO was going to lock in  ? 

[frd]

9 minutes ago, Stormchaserchuck1 said:

The Pacific looks good with MJO going through Phase 7 and possibly Phase 8.. models are developing and have trended toward a +PNA pattern. The Atlantic was looking blocky earlier in the month and that was exciting because it was associated with a Stratosphere warming to help sustain the pattern until possibly early January. In the last few days a big +NAO appeared in the medium range, and the 10mb warmings doesn't look as strong, although it's still a Strat warming happening. We will probably get colder later in the month, but it kind of has a bad taste when the fundamentals were looking so good, now it's just a MJO-amped pattern and nothing more. 

Warming events taking place at both the North Pole and the South Pole with assist the MJO in progressing into phase 8 in December.  

[frd]

Allan Huffman @RaleighWx   22m  

 

Well for all you #SSWE people out there. Today's 00z EPS showed all members (100%) showing a 10mb U wind reversal over the north pole around 11/28 to 11/29. The implications, are enhanced blocking risk in December and the possibility that the SPV will be further receptive to weakening later in the Winter which could influence the mid/late Winter.

 

[Stormchaserchuck1]

7 minutes ago, bncho said:

Correct me if I'm wrong, but essentially what you're saying is that we’ll probably still get colder later in December, but the pattern is now looking less “textbook perfect” than it did before; it looks more like a pattern driven mainly by the MJO rather than a more powerful and sustained cold setup from both the Pacific and the Atlantic.

Yeah it looks like it is MJO driven. The good news is the Pacific continues to act more like "Neutral ENSO" than La Nina. CPC PNA has been positive 21 of the last 29 months, and 12 of the last 19 months since the 23-24 El Nino ended. The 23-24 Strong Nino I believe changed something. I've watched it difficult for N. Pacific ridges to establish and sustain all year. ENSO does correlate the highest in Jan-Feb, but this is a pretty good +PNA now on models for the last week of Nov and early Dec... 

We had 8 straight +AO months earlier this year. We had 7 straight +NAO months until 2 months ago. The Atlantic side is not in a long term -NAO state, and it's decadal fluctuation index, so the consistency is important. That's why a good month of solid -NAO (2nd half of Nov in December) was looking good! Some change! It's kind of the same pattern happening. Maybe the Stratosphere warming will turn the NAO back negative in the 2nd half of December, but that's because of something, not a default state, which I was hoping for.

I still think we see -AO tendency this Winter because of low N. Hemisphere 500mb heights in the Summer and Fall. 

[Stormchaserchuck1]

7 minutes ago, frd said:

Didn't Webb say the - NAO was going to lock in  ? 

Did he? It was on models, now they have some pretty good +NAO troughing near Greenland with ridging underneath of it on the east coast. I think we are still below average temps though during the ridge because of -epo/+pna at the time. 

[Stormchaserchuck1]

4 minutes ago, frd said:

Allan Huffman @RaleighWx   22m  

You don't need a 500mb -NAO to have 10mb warming. Actually history is full of examples where the two are at odds. It correlates +40dm -NAO at Day+0, but a +100dm -NAO at ~+30 days (+25-35 days), which is the end of December. Let's see if we get a 2nd -NAO period later in Dec. 

[Stormchaserchuck1]

16 minutes ago, frd said:

Warming events taking place at both the North Pole and the South Pole with assist the MJO in progressing into phase 8 in December.  

Warming events don't happen in the Summer. You mean in June in the South Pole? 

[Terpeast]

1 hour ago, Stormchaserchuck1 said:

The Pacific looks good with MJO going through Phase 7 and possibly Phase 8.. models are developing and have trended toward a +PNA pattern. The Atlantic was looking blocky earlier in the month and that was exciting because it was associated with a Stratosphere warming to help sustain the pattern until possibly early January. In the last few days a big +NAO appeared in the medium range, and the 10mb warmings doesn't look as strong, although it's still a Strat warming happening. We will probably get colder later in the month, but it kind of has a bad taste when the fundamentals were looking so good, now it's just a MJO-amped pattern and nothing more. By fundamentals I mean holding a -NAO for more than 10 days. 

Which models/forecast periods are you looking at? 

[Stormchaserchuck1]

8 minutes ago, Terpeast said:

Which models/forecast periods are you looking at? 

https://www.meteo.psu.edu/ewall/ENSHGTAVGNH_6z/ensloopmref.html   0z EPS has the same thing. 

NAO is positive Thanksgiving until Dec 6. Now we have a good Pacific during that time, remember 13-14 and 14-15 had a favorable Pacific with +NAO and we did fine snow-wise. 

The Scan ridge is looking good at the end, but it's more reflecting the warming at 50mb and 10mb. 

 

[Terpeast]

3 minutes ago, Stormchaserchuck1 said:

https://www.meteo.psu.edu/ewall/ENSHGTAVGNH_6z/ensloopmref.html

NAO is positive Thanksgiving until Dec 6. Now we have a good Pacific during that time, remember 13-14 and 14-15 had a favorable Pacific with +NAO and we did fine snow-wise. 

The Scan ridge is looking good at the end, but it's more reflecting the warming at 50mb and 10mb. 

 

Oh I thought you were talking about the euro weeklies. I don't expect much from the nao until the SSW + scand ridging take effect and (hopefully) retrogrades over greenland

[Stormchaserchuck1]

1 minute ago, Terpeast said:

Oh I thought you were talking about the euro weeklies. I don't expect much from the nao until the SSW + scand ridging take effect and (hopefully) retrogrades over greenland

Hopefully it materializes. Probably not a given though. 

[cbmclean]

I continue to poo-poo the value of a -NAO in the first half of Dec; it's useless without antecedent cold to block in.  Well maybe not useless, but certainly much less useful.  That said, I think Chuck's point that it would be nice to see the +NAO base state change is exactly right, and so far, no evidence of seeing that happen.      

[Eskimo Joe]

Hey maybe the PDO is tilting towards our favor?

 

 

[CAPE]

2 hours ago, cbmclean said:

I continue to poo-poo the value of a -NAO in the first half of Dec; it's useless without antecedent cold to block in.  Well maybe not useless, but certainly much less useful.  That said, I think Chuck's point that it would be nice to see the +NAO base state change is exactly right, and so far, no evidence of seeing that happen.      

Ok but if current ens guidance has the right idea, the combo of a +PNA/-EPO and a southward stretched TPV will begin to provide a mechanism for cold air transport southeastward for the first week to 10 days in Dec.. Beyond that there are hints of Scand ridging expanding into the NAO space- if that does happen and we end up with a -NAO, the cold will be in place underneath.

[CAPE]

6 hours ago, bncho said:

Is December looking less and less good (because it seems like the beginning of the month has trended warmer), or is it just models rushing the pattern change like usual?

You sure about that?

[CAPE]

Latest Euro Weeklies for the period just beyond D15 on based on the 0z ens run. The progression of anomalous h5 heights into the NAO domain is more impressive than the previous run.

 

[cbmclean]

6 hours ago, CAPE said:

Ok but if current ens guidance has the right idea, the combo of a +PNA/-EPO and a southward stretched TPV will begin to provide a mechanism for cold air transport southeastward for the first week to 10 days in Dec.. Beyond that there are hints of Scand ridging expanding into the NAO space- if that does happen and we end up with a -NAO, the cold will be in place underneath.

Well sure, if we can get some -EPO cold in place and then launch the -NAO, then it's game on.  I was more referring to the loss of the -NAO that had been showing up as mentioned by Chuck, was not a huge loss in my opinion, although I'd still rather have it in place than not.

[Eskimo Joe]

4 minutes ago, cbmclean said:

Well sure, if we can get some -EPO cold in place and then launch the -NAO, then it's game on.  I was more referring to the loss of the -NAO that had been showing up as mentioned by Chuck, was not a huge loss in my opinion, although I'd still rather have it in place than not.

With our climate becoming increasingly hostile to snow each winter, we need as many things to go right as possible. 

[JenkinsJinkies]

I’m anticipating a busy panic room this year.

[Eskimo Joe]

7 hours ago, JenkinsJinkies said:

I’m anticipating a busy panic room this year.

While I hope to be wrong, I agree. We're investing a lot of hope in an early SSWE and the past 10 years have largely been putrid for snow lovers in this subforum. 

[Terpeast]

16 minutes ago, Eskimo Joe said:

While I hope to be wrong, I agree. We're investing a lot of hope in an early SSWE and the past 10 years have largely been putrid for snow lovers in this subforum. 

I can see that just based on the snowfall prediction contest thread. 

The early SSW doesn't really change my prediction for this winter much, if at all. If it does come to fruition, it may give us a front-loaded winter with a backend torch. If not, another SSWE may try again later given the neg QBO and given the shorter lag, we may see another 2-3 week window of opportunity in Jan or Feb. Getting both seems a little too much to ask for, imho.

[Blizzard of 93]

The advertised better pattern looks to be on track beginning around December 5th on the 0z EPS & 0z GEFS.

[Eskimo Joe]

13 minutes ago, Terpeast said:

I can see that just based on the snowfall prediction contest thread. 

The early SSW doesn't really change my prediction for this winter much, if at all. If it does come to fruition, it may give us a front-loaded winter with a backend torch. If not, another SSWE may try again later given the neg QBO and given the shorter lag, we may see another 2-3 week window of opportunity in Jan or Feb. Getting both seems a little too much to ask for, imho.

To be clear, I'm not debbing on this winter. We have several favorable factors working in our favor thus far, and as @WxUSAF has noted these torches advertised in the medium to long range have been muted as we close on the date. 

[Terpeast]

14 minutes ago, Eskimo Joe said:

To be clear, I'm not debbing on this winter. We have several favorable factors working in our favor thus far, and as @WxUSAF has noted these torches advertised in the medium to long range have been muted as we close on the date. 

Yeah, we've noticed the muting of torches as they get closer in time. I think it is because the Pacific is improving. We just need the Atlantic to cooperate with timing.

[Eskimo Joe]

14 minutes ago, Terpeast said:

Yeah, we've noticed the muting of torches as they get closer in time. I think it is because the Pacific is improving. We just need the Atlantic to cooperate with timing.

Yes that's definitely occurring. Hopefully we can get the PDO to return to a more neutral if not slightly positive state in the long term. 

[Bob Chill]

Winter rarely just blasts into the MA early season. It's a carving process and we're usually 3rd on the list when it happens (MW first, NE second, etc). First week of Dec looks like a carving process to me. This is an interesting jet panel. If you animate d10-15 it's pretty clear that the eps wants to press (or carve) the northern jet down into our latitudes. Still not good enough here but the process is ongoing 

 

Overall it's an encouraging jet structure with split flow and convergence. Mean QPF panels show moist SW flow embedded in this. If this verifies, areas to our west and NE will be in the crosshairs for overrunning type snowfall. If the carve continues southward it would be our first real window of opportunity beyond d15. Patterns like this can be active with precip but not really a big storm pattern. Which is probably good. It's really really hard early season to get a wound up storm to track underneath of us or be cold enough for snow. Much higher odds with a weaker shortwave zipping along

[Eskimo Joe]

4 minutes ago, Bob Chill said:

Winter rarely just blasts into the MA early season. It's a carving process and we're usually 3rd on the list when it happens (MW first, NE second, etc). First week of Dec looks like a carving process to me. This is an interesting jet panel. If you animate d10-15 it's pretty clear that the eps wants to press (or carve) the northern jet down into our latitudes. Still not good enough here but the process is ongoing 

 

Overall it's an encouraging jet structure with split flow and convergence. Mean QPF panels show moist SW flow embedded in this. If this verifies, areas to our west and NE will be in the crosshairs for overrunning type snowfall. If the carve continues southward it would be our first real window of opportunity beyond d15. Patterns like this can be active with precip but not really a big storm pattern. Which is probably good. It's really really hard early season to get a wound up storm to track underneath of us or be cold enough for snow. Much higher odds with a weaker shortwave zipping along

I'd take a continuous series of light to moderate events that don't erode a block, vs one "big dog" storm that melts off in 4 days. Snow-on-snow is the best!