2025-2026 ENSO

[GaWx]

30 minutes ago, donsutherland1 said:

In general, a PNA- pattern results in lighter snowfalls in the New York City area and northern Mid-Atlantic. The Boxing Day blizzard is a notable exception and the only KU snowstorm during December when the PNA was negative.

Hey Don,

 This is somewhat related and something I happened to compile yesterday about big NC snowstorms during -PNAs. First, note that the -PNA for the 2010 storm was only weak (-0.3). Also, what’s interesting about the list below of big NC snows during a -PNA is that only one of the 7 most -PNA 6”+ storms there were during a -NAO! Anyone know why or is this likely just from randomness? It’s a somewhat decent sized sample of 7 and 4 of the 7 had a moderate to strong +NAO as opposed to just a weak +NAO:

6”+ storms since 1950 at GSO and/or RDU: most negative PNA:

-1.1: 2/12-13/2014 (moderate +NAO)
-0.8: 1/22-24/1954 (moderate +NAO)
-0.8: 3/2-3/1960 (neutral NAO)
-0.7: 1/6-7/2017 (moderate +NAO)
-0.5: 3/9/1960 (neutral NAO)
-0.3: 12/26/2010 (moderate -NAO)
-0.3: 2/24-26/2015 (strong +NAO)

Daily PNA:

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

Daily NAO:

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

 

 

[EastonSN+]

3 minutes ago, GaWx said:

Hey Don,

 This is somewhat related and something I happened to compile yesterday about big NC snowstorms during -PNAs. First, note that the -PNA for the 2010 storm was only weak (-0.3). Also, what’s interesting about the list below of big NC snows during a -PNA is that only one of the 7 most -PNA 6”+ storms there were during a -NAO! Anyone know why or is this likely just from randomness? It’s a somewhat decent sized sample of 7 and 4 of the 7 had a moderate to strong +NAO as opposed to just a weak +NAO:

6”+ storms since 1950 at GSO and/or RDU: most negative PNA:

-1.1: 2/12-13/2014 (moderate +NAO)
-0.8: 1/22-24/1954 (moderate +NAO)
-0.8: 3/2-3/1960 (neutral NAO)
-0.7: 1/6-7/2017 (moderate +NAO)
-0.5: 3/9/1960 (neutral NAO)
-0.3: 12/26/2010 (moderate -NAO)
-0.3: 2/24-26/2015 (strong +NAO)

Daily PNA:

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

Daily NAO:

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

 

 

[GaWx]

16 minutes ago, EastonSN+ said:

 Yeah, way out in fantasyland! This reminds me of this Euro storm from last January in not as far out fantasyland:

  
 While this was gone on the very next run, this turned out to be when the historic 1/21-2/2025 Gulf coast/deep SE winter storm occurred.

[EastonSN+]

8 minutes ago, GaWx said:

 Yeah, way out in fantasyland! This reminds me of this Euro storm from last January I’m not as far out fantasyland:

  
 While this was gone on the very next run, this turned out to be when the historic 1/21-2/2025 Gulf coast/deep SE winter storm occurred.

If the NAO is as strong as predicted, it would favor southern areas. The boxing day blizzard also hit NC hard.

[donsutherland1]

30 minutes ago, GaWx said:

Hey Don,

 This is somewhat related and something I happened to compile yesterday about big NC snowstorms during -PNAs. First, note that the -PNA for the 2010 storm was only weak (-0.3). Also, what’s interesting about the list below of big NC snows during a -PNA is that only one of the 7 most -PNA 6”+ storms there were during a -NAO! Anyone know why or is this likely just from randomness? It’s a somewhat decent sized sample of 7 and 4 of the 7 had a moderate to strong +NAO as opposed to just a weak +NAO:

6”+ storms since 1950 at GSO and/or RDU: most negative PNA:

-1.1: 2/12-13/2014 (moderate +NAO)
-0.8: 1/22-24/1954 (moderate +NAO)
-0.8: 3/2-3/1960 (neutral NAO)
-0.7: 1/6-7/2017 (moderate +NAO)
-0.5: 3/9/1960 (neutral NAO)
-0.3: 12/26/2010 (moderate -NAO)
-0.3: 2/24-26/2015 (strong +NAO)

Daily PNA:

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

Daily NAO:

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

 

 

I suspect that when it comes to snowstorms in parts of the Southeast, more is involved than the pattern itself. Synoptic details are critical and outweigh the teleconnections. One sees a similar outcome in the spring in the Middle Atlantic region as wave lengths shorten and the state of the teleconnections becomes less important.

[SnowGoose69]

49 minutes ago, donsutherland1 said:

While the AO and NAO are looking good on the latest GEFS, the PNA is not.

It’s going to be a battle in January I think of which one gives in first.  If it’s the NAO winter is probably done for if we assume we get the February most expect we do based on the IOD/ENSO.  If it’s the PNA maybe we can get a crazy 2-3 weeks.  I’d still lean towards February probably being bad but in La Niña to El Niño transition years we’ve seen March sometimes be good  

[donsutherland1]

46 minutes ago, GaWx said:

Hey Don,

 This is somewhat related and something I happened to compile yesterday about big NC snowstorms during -PNAs. First, note that the -PNA for the 2010 storm was only weak (-0.3). Also, what’s interesting about the list below of big NC snows during a -PNA is that only one of the 7 most -PNA 6”+ storms there were during a -NAO! Anyone know why or is this likely just from randomness? It’s a somewhat decent sized sample of 7 and 4 of the 7 had a moderate to strong +NAO as opposed to just a weak +NAO:

6”+ storms since 1950 at GSO and/or RDU: most negative PNA:

-1.1: 2/12-13/2014 (moderate +NAO)
-0.8: 1/22-24/1954 (moderate +NAO)
-0.8: 3/2-3/1960 (neutral NAO)
-0.7: 1/6-7/2017 (moderate +NAO)
-0.5: 3/9/1960 (neutral NAO)
-0.3: 12/26/2010 (moderate -NAO)
-0.3: 2/24-26/2015 (strong +NAO)

Daily PNA:

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

Daily NAO:

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

 

 

Here's some data for NYC for January and March (1980-2025):

[GaWx]

1 hour ago, donsutherland1 said:

While the AO and NAO are looking good on the latest GEFS, the PNA is not.

 I’m very curious to see what happens in Jan with the PNA based on -ENSO strong Dec -PNA analogs like 2021, 2013, 2010, 2008, and 1984 whose Jan PNA all rose 1.8++ from Dec. That’s still well beyond what models can see with any notable degree of skill. My GEFS PNA forecasting images for Dec 2021-Jan 2022 displayed that well.

[SnowGoose69]

3 minutes ago, GaWx said:

 I’m very curious to see what happens in Jan with the PNA based on -ENSO strong Dec -PNA analogs like 2021, 2013, 2010, 2008, and 1984 whose Jan PNA all rose 1.8++ from Dec. That’s still well beyond what models can see with any notable degree of skill.

00 and 97 I think also went pretty strong +PNA I think but can’t recall if they were negative in December or not.  I want to say they were not 

[GaWx]

13 minutes ago, SnowGoose69 said:

00 and 97 I think also went pretty strong +PNA I think but can’t recall if they were negative in December or not.  I want to say they were not 

-Actually, Dec of 1996, indeed, was still another -ENSO strong -PNA that transitioned to a +PNA in Jan after a 1.8+ rise.

-Dec of 1999 had a neutral PNA. So, that isn’t in this group.

*Corrected for typo…Dec of 1999

[donsutherland1]

31 minutes ago, GaWx said:

 I’m very curious to see what happens in Jan with the PNA based on -ENSO strong Dec -PNA analogs like 2021, 2013, 2010, 2008, and 1984 whose Jan PNA all rose 1.8++ from Dec. That’s still well beyond what models can see with any notable degree of skill. My GEFS PNA forecasting images for Dec 2021-Jan 2022 displayed that well.

It will be interesting to see how things evolve. Since 1980, December PNA- cases have been followed by January PNA+ cases. Prior to 1980, December PNA- cases were generally followed by January PNA- cases. It is possible that the less stable PNA state is, at least in part, a result of Arctic amplification.

[Maestrobjwa]

1 hour ago, donsutherland1 said:

It will be interesting to see how things evolve. Since 1980, December PNA- cases have been followed by January PNA+ cases. Prior to 1980, December PNA- cases were generally followed by January PNA- cases. It is possible that the less stable PNA state is, at least in part, a result of Arctic amplification.

I'm curious to see the resulting snow results for BWI & NYC after those PNA spike years...but off the top of my head it seems only two ninos and 13-14 produced down this way. -ENSO was all below average.

[donsutherland1]

22 minutes ago, Maestrobjwa said:

I'm curious to see the resulting snow results for BWI & NYC after those PNA spike years...but off the top of my head it seems only two ninos and 13-14 produced down this way. -ENSO was all below average.

For Baltimore:

[GaWx]

 On 12/26/21, when the PNA had been negative all month/way down at -1.8 that day and Baltimore (among others) had just had a miserably mild 68F Christmas high with very mild to continue through New Year’s, this (see image below) was the 12/26/21 GEFS two week PNA forecast, which went to 1/9/22: still down at -0.6 on 1/9/22 and no clearcut sign that 1/9/22 was going to be the start of a 38 day long +PNA as well as Jan ending up the snowiest month by far there since Jan of 2016 along with it being the coldest month since Jan of 2018:

@donsutherland1

*Edit: The main points are:
- The models can’t see out that far with notable skill and that includes forecasting the PNA/general patterns
- -ENSO -PNA Decembers since 1984 all transitioned to +PNA Jans

[snowman19]

3 hours ago, SnowGoose69 said:

It’s going to be a battle in January I think of which one gives in first.  If it’s the NAO winter is probably done for if we assume we get the February most expect we do based on the IOD/ENSO.  If it’s the PNA maybe we can get a crazy 2-3 weeks.  I’d still lean towards February probably being bad but in La Niña to El Niño transition years we’ve seen March sometimes be good  

The modeling (ensembles/operationals) this afternoon is showing a decidedly east-based -NAO going into the beginning of January, also still holding on to the -PNA as well. If the true east-based -NAO is correct, it would be quite the change from what we have seen over the last 10 years or so with -NAO’s, 

[donsutherland1]

21 minutes ago, GaWx said:

 On 12/26/21, when the PNA had been negative all month/way down at -1.8 that day and Baltimore (among others) had just had a miserably mild 68F Christmas high with very mild to continue through New Year’s, this (see image below) was the 12/26/21 GEFS two week PNA forecast, which went to 1/9/22: still down at -0.6 on 1/9/22 and no clearcut sign that 1/9/22 was going to be the start of a 38 day long +PNA as well as Jan ending up the snowiest month by far there since Jan of 2016 along with it being the coldest month since Jan of 2018:

@donsutherland1

*Edit: The main points are:
- The models can’t see out that far with notable skill and that includes forecasting the PNA/general patterns
- -ENSO -PNA Decembers since 1984 all transitioned to +PNA Jans

Very interesting archived forecast. Is this information publicly-accessible and, if so, do you have a link?

[michsnowfreak]

I frequently hear new englanders complain of the Grinch storm, a storm/temps right around Christmas that melt away a true White Christmas. We got our taste of that today. Snow has been on the ground since November 29th....but a Grinch showed up 1 week before Christmas today. Fortunately, the Christmas season is more than just the 25th, but its very impressive to see the extreme temps the CONUS has seen this month, both way below and way above avg. It bares repeating, this is a trademark of a traditional La Nina. Last year we heard that it "didnt act" like a Nina. This winter seems to be acting just like a Nina.

[jconsor]

5 hours ago, donsutherland1 said:

In general, a PNA- pattern results in lighter snowfalls in the New York City area and northern Mid-Atlantic. The Boxing Day blizzard is a notable exception and the only KU snowstorm during December when the PNA was negative.

True, but we just had a snowstorm produce widespread 6-8"+ from I-95 south and east (other than lighter amounts in the urban heat island near NYC) with -PNA, though in that case the NAO was slightly positive and AO highly positive.

*If* we are going to see a 6"+ snowstorm in a -PNA pattern during a La Nina, it almost definitely will come from northern stream system e.g. a highly amplified clipper/Miller B.

[GaWx]

52 minutes ago, donsutherland1 said:

Very interesting archived forecast. Is this information publicly-accessible and, if so, do you have a link?

 I have it by luck on my phone as I happened to started saving a few in Dec of 2021 and Jan of 2022 I think because of long range hints on the CFS (of all models, which I also saved a bunch of…so kudos to the CFS then!) starting to show very long range big colder changes in late Dec and especially Jan. Since then, I happened to saved a lot near and after the 2/16/2023 SSWE, which showed that the -NAO/-AO were initially way underdone/missed. Since then I’ve saved a bunch during the winters.