2025-2026 ENSO

[brooklynwx99]

the Pacific jet is going to retract and shift equatorward after its poleward extension next week, which should lead to the -EPO that we're waiting for. I have pretty high confidence in this -EPO developing; the progression makes sense. BN to much BN temps in the East would follow into early Dec

trough near Japan/HI are also old-school signs of a favorable Pacific pattern

[snowman19]

[EasternLI]

12 minutes ago, brooklynwx99 said:

the Pacific jet is going to retract and shift equatorward after its poleward extension next week, which should lead to the -EPO that we're waiting for. I have pretty high confidence in this -EPO developing; the progression makes sense. BN to much BN temps in the East would follow into early Dec

trough near Japan/HI are also old-school signs of a favorable Pacific pattern

Sharp rise in momentum starting to percolate into the circulation. Good stuff. 

[stadiumwave]

CFS Weeklies just now got on board with some cold. Has been baby stepping for several runs. 

NOV 27-DEC 7

[donsutherland1]

Here's the evolution of the CFSv2 forecast for December. It should be noted that all the timeframes, the CFSv2 is not yet in its high skill area.

[anthonymm]

2 hours ago, donsutherland1 said:

For Washington, DC to New York City, a PNA+ is far more common for days with 6" or more snowfall except during the second half of February and afterward when the wave lengths shorten. New York City statistics since 1950:

For January, when wave lengths are at their longest, a PNA+ was present for 92.5% of days with 6" or more snowfall in New York City.

For Boston, the PNA+ plays a smaller role.

Yup PNA is king south of New England. NYC's not reaching 4" for December if that western trough hangs out for the entirety of the month. That pretty much guarantees a BN winter for us. Forgot who said it but 19" is likely a (generous) upper bound for our snow totals this winter. 

[FPizz]

10 hours ago, PhiEaglesfan712 said:

February 2006 wasn't all that bad. At least we got a return to cold, and a snowstorm on the 11th-12th. I'd gladly sign up for that after the last 3 or 4 winters.

But please, no repeat of 1989-90, when spring pretty much began in January.

Feb 06 was a good month in CNJ, 20.5", 89/90 stunk, but teased us with a Nov snowstorm.

[stadiumwave]

45 minutes ago, donsutherland1 said:

Here's the evolution of the CFSv2 forecast for December. It should be noted that all the timeframes, the CFSv2 is not yet in its high skill area.

 

High skill is like the last 3 days, lol. But hey, it is not usually that bad with the end result. 

[kazimirkai]

14 hours ago, GaWx said:

Allan Huffman going with a cold January in the E US. I wonder if this is because of a prog for a very early SSWE followed by a lagged cold effect in Jan: I’d be more than happy with this. I’d love another cold Jan! Not having a warmer than normal La Niña winter in the majority of the SE including another cold Jan would be a victory!

This seems reasonable. I think this early December cold wave is mainly driven by high frequency signals, mainly the 7 phase MJO, but i think its too early for the SSW to be having any impact. Roundy thinks there will be some warmth in late December as the MJO move back towards 1 and 2 (abeit prolonged due to an easterly eq. Rossby wave continuing convection in region 7), but it seems like it may have a weaker signal at that point so influences from things like the SSW on top of the low-frequency state (troughy in the east) would lead so something like this. 

[kazimirkai]

2 hours ago, EasternLI said:

Sharp rise in momentum starting to percolate into the circulation. Good stuff. 

Warm waters into the W pac. from this westerly wind burst are priming the ENSO for a real shift come the next big event. 

[kazimirkai]

48 minutes ago, anthonymm said:

Yup PNA is king south of New England. NYC's not reaching 4" for December if that western trough hangs out for the entirety of the month. That pretty much guarantees a BN winter for us. Forgot who said it but 19" is likely a (generous) upper bound for our snow totals this winter. 

Pretty uncommon for short-range oscillations like the PNA to remain strongly in either state for a whole month. I wouldn't put too much weight on this negative flip, though it might explain the great lakes track that seems more likely during the latter half of nov. and perhaps during the first week of dec.

[jm1220]

48 minutes ago, anthonymm said:

Yup PNA is king south of New England. NYC's not reaching 4" for December if that western trough hangs out for the entirety of the month. That pretty much guarantees a BN winter for us. Forgot who said it but 19" is likely a (generous) upper bound for our snow totals this winter. 

If we can fire up some Miller Bs that don’t develop too late, NYC has a chance at 20”. There very likely won’t be Miller As during a Nina, and clippers as we’ve seen have largely died out. Maybe a lucky SWFE can tack on 4-6” like the one last winter. But that’s really NYC’s path to anything near normal in this regime. 

[EasternLI]

25 minutes ago, kazimirkai said:

Warm waters into the W pac. from this westerly wind burst are priming the ENSO for a real shift come the next big event. 

Yeah, that will be interesting to watch evolve. Extended range EPS and GEFS are advertising this WWB to push out to the dateline. Which has proven difficult to do in other recent La Niña years. So I'm curious to see how this one goes as we move into December. 

[GaWx]

5 hours ago, donsutherland1 said:

For Washington, DC to New York City, a PNA+ is far more common for days with 6" or more snowfall except during the second half of February and afterward when the wave lengths shorten. New York City statistics since 1950:

For January, when wave lengths are at their longest, a PNA+ was present for 92.5% of days with 6" or more snowfall in New York City.

For Boston, the PNA+ plays a smaller role.

 Great stuff, Don! Since I had seen similar results in looking at the following for RDU big snows, I figured you and others might find this interesting:

 

21 RDU 6”+ snowstorms since 1950 (Niña or -neutral ENSO bolded)

1/19/1955 Niña neut PNA, neut AO, moderate -NAO

12/11/1958 mod +PNA, neut AO and NAO

3/2-3/1960 mod -PNA, neut AO and NAO

3/9/1960 weak -PNA, strong -AO, neutral NAO

2/26/1963 -neutral strong +PNA, mod +AO, neutral NAO

1/26/1966 neut PNA, strong -AO and -NAO

2/9/1967 -neutral mod +PNA, weak +AO, moderate +NAO

3/1/1969 strong +PNA/-AO, moderate -NAO

1/7-8/1973 weak +PNA, neut AO, strong -NAO

2/18-9/1979 neut PNA/AO/NAO

3/1-2/1980 neut PNA/AO, moderate +NAO

3/24/1983 mod +PNA/-AO, neutral NAO

2/6/1984 -neutral mod +PNA/+AO, strong +NAO

1/7/1988 mod +PNA, neut AO, weak +NAO

2/17-8/1989 Niña neut PNA, strong +AO/+NAO

1/24-5/2000 Niña mod +PNA, neut AO, moderate -NAO

1/2-3/2002 -neutral strong +PNA, neut AO, moderate -NAO

2/26-7/2004 neut PNA, strong -AO, weak -NAO

12/26/2010 Niña weak -PNA, strong -AO, moderate -NAO

1/17/2018 Niña neut PNA, weak +AO, strong +NAO

12/9-10/2018 mod +PNA, neut AO, moderate +NAO
—————————

For the 21 storms

-11 (52%) +PNA, 7 (33%) neutral PNA, 3 (14%) -PNA

-7 (33%) +NAO, 6 (29%) neutral NAO, 8 (38%) -NAO

So, whereas 52% had a +PNA vs only 14% with a -PNA, 38% had a -NAO vs 33% with a +NAO

So, whereas there were almost 4 times as many with a +PNA vs a -PNA, -NAO vs +NAO has been much more balanced.
————

The above is for all ENSO.
What about for just -ENSO?

-5 (56%) +PNA, 3 (33%) neutral PNA, 1 (5%) -PNA

-4 (44%) +NAO, 1 (11%) neutral NAO, 4 (44%) -NAO

So, whereas 56% had a +PNA vs only 5% with a -PNA, 44% had a -NAO vs 44% with a +NAO

So, whereas there were 5 times as many with a +PNA vs a -PNA, -NAO vs +NAO has been totally balanced.
—————

I found similar results for Greensboro and Atlanta. Bottom line: in the SE US, a +PNA is a bigger driver of big snowstorms than is a -NAO.

Daily PNA link:

https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.pna.index.b500101.current.ascii

Daily NAO link:

https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.nao.index.b500101.current.ascii

 

————

*Edit: Interestingly, looking back at big storms at RDU and GSO, the last 6 (2014-18) were all with a moderate to strong +NAO! So, there hasn’t been even one 6”+ snow at either RDU or GSO with a -NAO (even a weak one) since way back on 12/26/2010! This could, of course, be from randomness. But I’m not sure about that considering what @bluewavehas said about -NAO ridges tending to hook up with SE ridges more often than in the past. Hmmmm….

 

Edit #2: I just noticed this for the 21 RDU big snowstorms for the AO:

5 +AO, 11 neutral AO, 5 -AO

So, neutral has been favored.

[donsutherland1]

2 hours ago, anthonymm said:

Yup PNA is king south of New England. NYC's not reaching 4" for December if that western trough hangs out for the entirety of the month. That pretty much guarantees a BN winter for us. Forgot who said it but 19" is likely a (generous) upper bound for our snow totals this winter. 

Here's the data for December vs. January-April snowfall for New York City for La Niña winters 1979-80 through 2024-2025. 2024-2025 is officially listed as cold neutral. December 2024 had 2.8" of snow.

 

[donsutherland1]

2 hours ago, stadiumwave said:

 

High skill is like the last 3 days, lol. But hey, it is not usually that bad with the end result. 

It does seem to become skillful within a week of the following month.