2025-2026 ENSO

[MJO812]

9 minutes ago, FPizz said:

After the first few days, it gets better for the east like I posted above using 2013

Take the ops with a grain of salt

[Stormchaserchuck1]

23 minutes ago, stadiumwave said:

12z suites showing a big cold dump in rockies, great plains & midwest with a pattern very early DEC 2013 looking. The pattern produced some ice & snow in the MW & OV as well back in 2013.

That's a +400dm mean ridge over Alaska for a 7-day period. Not really the same as the 1 panel you posted above. We are going to get a -EPO period but it's not going to be as strong or sustain like 2013. 

[Stormchaserchuck1]

26 minutes ago, George001 said:

You absolutely could for northern areas, December 2007 is a good example. Depends on where the boundary sets up.

Alaska is a big spot. Neutral or negative H5 is going to give you a warmer pattern pretty far north. If the ridge stays over Alaska (probably unlikely) the northern areas will be cold. I'm mostly talking about Dec 6-7-> 

[leo2000]

Seems like some utter nonsense talk about a possible AO and positive NAO . A major SSW favors, negative AO and negative NAO phases. 

[Stormchaserchuck1]

3 minutes ago, leo2000 said:

Seems like some utter nonsense talk about a possible AO and positive NAO . A major SSW favors a negative AO and negative NAO phases. 

There is a lag

[Stormchaserchuck1]

Actually the 12z GEFS looks completely different from the 0z EPS over the N. Pacific. It actually has a trough in the gulf of alaska where the EPS has a ridge. EPS has been doing better so far, but it's an interesting split. I would guess the 2 models are handling the MJO differently?

[leo2000]

17 minutes ago, Stormchaserchuck1 said:

There is a lag

Yes there is, the AO looks to go positive but it's only temporary then return negative or neutral state within the next two weeks. The weeklies also keep an negative EPO which did well last winter. I also don't think we are losing a negative EPO as all forecasts have it diving deeply negative some even have it below -4 sigma. 

[MJO812]

17 minutes ago, leo2000 said:

Seems like some utter nonsense talk about a possible AO and positive NAO . A major SSW favors, negative AO and negative NAO phases. 

Exactly 

[donsutherland1]

34 minutes ago, leo2000 said:

Seems like some utter nonsense talk about a possible AO and positive NAO . A major SSW favors, negative AO and negative NAO phases. 

Several things:

1) There remains a lot of uncertainty how the stratospheric warming will propagate. Propagation could be a big factor in prolonging/strengthening or bringing back Atlantic blocking. 

2) Even as stratospheric warming often (not always) propagates favorably to build or prolong/strengthen Atlantic blocking, one should not immediately dismiss hints of evidence to the contrary. Confirmation bias is bad for forecasting.

Such evidence exists e.g., here's the AO forecast from the EPS 46-day forecast:

Although the below table talks about considering climate change-related impacts on forecasts, I highlighted the section that relates to how  and why confirmation bias skews forecasts:

A systematic forecasting framework allows one to acknowledge such evidence while avoiding rash decisions from model noise. As I don't have a crystal ball to have 100% confidence in whether or not the above AO forecast will verify, I have made a note to continue to monitor developments.

Needless to say, there is more to it than such a framework. Each scenario has clusters of outcomes (not discussed above). 

It should be noted that such frameworks don't guarantee accuracy, but they do reduce the risks that can otherwise lead to bad forecasts, especially when one is dealing with timeframes over which model skill is limited or worse.

Finally, the 11/22 12z guidance has reaffirmed the December 1-10 idea. Indeed, more than half of the 11/22 0z EPS ensembles suggested 1" or more snow in Detroit and Toronto (a good signal for measurable snow prospects from this far out). I expect those figures to hold up with the 12z cycle.

[donsutherland1]

Below is an illustration of an extreme forecast that is being pushed on Twitter/X despite the lack of evidence to actually support the idea (e.g., small pool of deep cold in the Northern Hemisphere) and the lack of skill in guidance from this far out:

"Lower Rio Grande Valley" doesn't specify a specific point or location for purposes of verification, so it will be excluded.

Here's the forecast coupled with December 2000-2024 statistics:

This illustrative example will be verified at the end of December. Given the estimated probabilities for various outcomes, the odds are strongly against the extreme forecast verifying in more than one of the above locations. 

[qg_omega]

1 hour ago, leo2000 said:

Seems like some utter nonsense talk about a possible AO and positive NAO . A major SSW favors, negative AO and negative NAO phases. 

Utter nonsense

[leo2000]

19 minutes ago, qg_omega said:

Utter nonsense

Most of the time it does sometimes it doesn't but most of the time it does.The AO is fluctuating now but doesn't mean it's going to take stay positive. 

[LakePaste25]

People put too much emphasis on the AO/NAO/SPV stuff. You can have a +TNH/Hudon vortex anchored in place all winter coupled with an SPV on roids. This was mostly the case in 13-14/14-15. Then again I am biased towards the great lakes, but I like seeing the indo-pacific warm pool and the -EPO pattern show up. 

[donsutherland1]

8 minutes ago, LakePaste25 said:

People put too much emphasis on the AO/NAO/SPV stuff. You can have a +TNH/Hudon vortex anchored in place all winter coupled with an SPV on roids. This was mostly the case in 13-14/14-15. Then again I am biased towards the great lakes, but I like seeing the indo-pacific warm pool and the -EPO pattern show up. 

That’s true. Unfortunately, there’s no daily TNH index to quantify things. 

[stadiumwave]

4 hours ago, Stormchaserchuck1 said:

That's a +400dm mean ridge over Alaska for a 7-day period. Not really the same as the 1 panel you posted above. We are going to get a -EPO period but it's not going to be as strong or sustain like 2013. 

Yep, its about the cold & pattern of the period. Obviously I posted a 7 day mean of 2013 & only one specific frame of today's 12z GFS. The system on the GFS is very similar to the system in early DEC 2013. Not making a point about the entire winter. 

[40/70 Benchmark]

5 hours ago, George001 said:

You absolutely could for northern areas, December 2007 is a good example. Depends on where the boundary sets up.

He is speaking from a mid Atlantic perspective. We are fine.

[jm1220]

5 hours ago, stadiumwave said:

12z suites showing a big cold dump in rockies, great plains & midwest with a pattern very early DEC 2013 looking. The pattern produced some ice & snow in the MW & OV as well back in 2013.

 

Below you can click the link & watch the 2m Temp progression over that week. Underneath image you will click on "Go Forward one day":

https://psl.noaa.gov/cgi-bin/data/composites/comp.day.pl?var=2m+Air+Temperature&level=Surface&iy[1]=&im[1]=&id[1]=&iy[2]=&im[2]=&id[2]=&iy[3]=&im[3]=&id[3]=&iy[4]=&im[4]=&id[4]=&iy[5]=&im[5]=&id[5]=&iy[6]=&im[6]=&id[6]=&iy[7]=&im[7]=&id[7]=&iy[8]=&im[8]=&id[8]=&iy[9]=&im[9]=&id[9]=&iy[10]=&im[10]=&id[10]=&iy[11]=&im[11]=&id[11]=&iy[12]=&im[12]=&id[12]=&iy[13]=&im[13]=&id[13]=&iy[14]=&im[14]=&id[14]=&iy[15]=&im[15]=&id[15]=&iy[16]=&im[16]=&id[16]=&iy[17]=&im[17]=&id[17]=&iy[18]=&im[18]=&id[18]=&iy[19]=&im[19]=&id[19]=&iy[20]=&im[20]=&id[20]=&monr1=12&dayr1=1&monr2=12&dayr2=1&iyr[1]=2013&filenamein=&plotlabel=&lag=0&labelc=Color&labels=Shaded&type=2&scale=&label=0&skip_vector=&cint=&lowr=&highr=&istate=0&proj=North+America&xlat1=&xlat2=&xlon1=&xlon2=&custproj=Cylindrical+Equidistant&level1=1000mb&level2=10mb&Submit=Create+Plot

 

 

Trough east of Hawaii rule-that trough should push east but we have to be patient until probably second half of the month. Hopefully the SE ridge can be muted by then. 

[40/70 Benchmark]

10 hours ago, snowman19 said:

Obviously way too early to declare victory, but if this SPV progression verifies, at least the December ideas in your winter forecast are going to be very good. Paul Roundy is also in agreement with you that the PNA goes negative/RNA once we start getting towards mid-December based on the expected progression of low frequency tropical convective forcing…..

 

 

 

^ “This morning's zonal GPH anomaly plot + GFS forecast, showing the strato PV disturbance peaking during the week/10 days, and reaching down to about 50 hPa.

There appears to be some propagation to lower levels later on, but the models contrast sharply in this regard, with ECM showing a re-strengthening of the PV in the same timeframe.

It aligns with the overall trend observed, with the current PV displacement resulting from a stronger strato anticyclone over Alaska/Canada, and the vortex core shifting over Siberia.

After that, ENS members show a possible re-centering over the Arctic, with the anticyclonic area losing intensity and effects over the PV.

We'll need to monitor what happens in the next two weeks or so.”

 

 

If you look at December snowfall for my analogs, it's good in NE and not so great in the mid Atlantic.

[SnowGoose69]

No surprise to me, a trend already showing today that the storm near 12/1 in the Plains/MW may not be as strong.  Solutions were just unrealistically amped the previous 2 days which is why I said be wary of bridge jumping over the SER 12/1-12/4 because if we went the way we've gone most recent winters, those types of bombs, even in that part of the country have been hard to come by.   Weaker or more strung out system there that SER won't pump anywhere near that strong

[mitchnick]

In light of the current weak Niña numbers, if correct, today's progged 850 wind anomalies off the Eps should spell the demise of the Niña before the end of December. 

[raindancewx]

I was in Japan for two weeks ending yesterday - no rain or storms at all for the entire two week period. Was interesting to see as Tokyo gets 3-4 inches of rain in an average November. Temps in the mid-50s to 70 each day. Even Mt. Fuji (12,000+ peak) didn't have any snow on the peak visually by the time I was going back to Tokyo on the Shinkansen from Hirishoma.

December should have some cold but I've never expected a particularly brutal month overall. Part of it should be pretty cold and part of it pretty warm that is why I never emphasized it a month or so ago. Longer term, you see predominantly high pressure showing south of Kamchatka right now. So the storms that were flagged by that late Oct-Nov for the time frame now (lot of lows there, back then) will stop and reverse in about two weeks and the pattern should see a whole sale change for a bit.

The CPC 6-10 and 8-14 outlooks show the pattern I expect in the "good parts" of the winter - pretty wet. Widespread cold. But it won't do that each week.

I always assumed one part of Nov would be pretty cold in the East and another part much colder in the West, as that's what the blend of 2013 and 2024 implied - you can see that's played out a bit to some extent with a much colder pattern in the SW recently then at the start of the month. But the month will finish pretty warm nationally.

[snowman19]

@40/70 Benchmark Paul still expecting a -PNA/SE ridge to develop by mid-December based on the low frequency forcing:
 

[snowman19]

If you look at December snowfall for my analogs, it's good in NE and not so great in the mid Atlantic.

As far as the the SPV, it looks like there is going to be a rather fast recovery and rapid strengthening next month, as you predicted

[40/70 Benchmark]

50 minutes ago, snowman19 said:

As far as the the SPV, it looks like there is going to be a rather fast recovery and rapid strengthening next month, as you predicted

 

 

 

 

 

 

 

 

 

 

 

 

Yea, I said back to approaching climo by Xmas week, and that run reflects that.