2024-2025 La Nina

[snowman19]

The models have really started to bail on the SSW and an SPV split. It’s becoming more of a wave reflection event now and a major SSWE and split is looking less and less likely:
 

 

 

 

 

 

 

 

 

[snowman19]

The last few GFS runs have reversed away from a mid-Feb major SSW (10 mb 60N zonal mean winds 6Z 1/30 run: looked like a major SSW with an amazing split  with SPV obliterated

 
6Z 2/3 run: doesn’t even look close to a major SSW

 
 This is a crucial period in the forecasting and will need to revert back in the major SSW direction very soon to keep hope alive for one. As it is, I’m very disappointed to see these last few GFS runs.
Edit: 0Z Euro for same time: in between but closer to 6Z GFS and thus not even close to a major SSW

You beat me to it. This looks like it’s going to be a very big fail for those on twitter who have been hyping and basically guaranteeing a February, 2018 SSWE redux the last week. A major SSWE and SPV split is starting to look extremely unlikely. Jason Furtado nailed this happening last week: 

[snowman19]

47 minutes ago, GaWx said:

The last few GFS runs have reversed away from a mid-Feb major SSW (10 mb 60N zonal mean winds <0). For example, compare these two runs:

6Z 1/30 run: looked like a major SSW with an amazing split  with SPV obliterated

 

6Z 2/3 run: doesn’t even look close to a major SSW

 

 This is a crucial period in the forecasting and will need to revert back in the major SSW direction very soon to keep hope alive for one. As it is, I’m very disappointed to see these last few GFS runs.

Edit: 0Z Euro for same time: in between but closer to 6Z GFS and thus not even close to a major SSW

@Allsnow

[MJO812]

2 minutes ago, snowman19 said:

@Allsnow

This doesn't mean warmth is on the way . We don't need a split to get into a favorable pattern . 

[snowman19]

3 minutes ago, MJO812 said:

This doesn't mean warmth is on the way . We don't need a split to get into a favorable pattern . 

I never said it means warmth and it’s going to get very cold and blocking is going to develop. I’d have to be an idiot to deny that fact. However, it does mean that the blocking and cold is not going to lock in for a month or two like it may have, had we had a major SSWE and subsequent SPV split, i.e. March/April 2018

[MJO812]

2 minutes ago, snowman19 said:

I never said it means warmth and it’s going to get very cold and blocking is going to develop. I’d have to be an idiot to deny that fact. However, it does mean that the blocking and cold is not going to lock in for a month or two like it may have, had we had a major SSWE and subsequent SPV split, i.e. March/April 2018

The PV stretching is also really good. We shall see .

[brooklynwx99]

IMO this is more of a bottom-up event... the 50mb impacts on the stratosphere are more important for influencing the troposphere most of the time anyway, and a significant disruption is likely. the SPV stuff is only serving to bolster the tropospheric processes that will occur over the next two weeks

[GaWx]

 Jan 2025 PDO rose to -1.32, which is the highest since Jan of 2023 and which compares to Dec’s -2.04, Nov’s -3.13, and Oct’s -3.80. Based on ~stalling since late Dec, the big rise may be done for awhile. @snowman19

2024 -1.57 -1.33 -1.52 -2.11 -2.98 -3.15 -3.00 -2.91 -3.56 -3.80 -3.13 -2.04
2025 -1.32

[PhiEaglesfan712]

23 minutes ago, GaWx said:

 Jan 2025 PDO rose to -1.32, which is the highest since Jan of 2023 and which compares to Dec’s -2.04, Nov’s -3.13, and Oct’s -3.80. Based on ~stalling since late Dec, the big rise may be done for awhile. @snowman19

2024 -1.57 -1.33 -1.52 -2.11 -2.98 -3.15 -3.00 -2.91 -3.56 -3.80 -3.13 -2.04
2025 -1.32

It wouldn't surprise me if 2025's PDO takes a similar path to 2013. Like we did at the end of 2024, there was a big PDO rise at the end of 2012 (before leveling out):

2012 -1.85 -1.35 -1.66 -1.01 -2.12 -1.63 -2.40 -2.60 -2.99 -1.22 -0.66 -1.31
2013 -1.10 -1.42 -1.48 -0.72 -0.40 -1.19 -1.34 -1.56 -1.00 -1.65 -1.09 -1.04

Of course, as we know, the leveling out was followed by the rise (and eventual flip to +PDO) in 2014:

2014 -0.57 -0.42  0.30  0.36  1.27 -0.28  0.25  0.34  0.76  1.43  1.35  1.86

 

[GaWx]

13 minutes ago, PhiEaglesfan712 said:

It wouldn't surprise me if 2025's PDO takes a similar path to 2013. Like we did at the end of 2024, there was a big PDO rise at the end of 2012 (before leveling out):

2012 -1.85 -1.35 -1.66 -1.01 -2.12 -1.63 -2.40 -2.60 -2.99 -1.22 -0.66 -1.31
2013 -1.10 -1.42 -1.48 -0.72 -0.40 -1.19 -1.34 -1.56 -1.00 -1.65 -1.09 -1.04

Of course, as we know, the leveling out was followed by the rise (and eventual flip to +PDO) in 2014:

2014 -0.57 -0.42  0.30  0.36  1.27 -0.28  0.25  0.34  0.76  1.43  1.35  1.86

 

Fwiw 1/31/25 CANSIPS is still calling for a Modoki El Niño forming in July but the signal is a little weaker. It’s been calling for this since the July 31st run! I know you’ve been insisting no El Nino til 2026. We’ll see I guess. CANSIPS could be out to lunch though I hope not.

[GaWx]

23 hours ago, GaWx said:

Today’s Euro Weeklies 10 mb: still trending in direction of major SSW Feb 13-14:

Today’s mean down to +16 then vs +22, +28  and +39 on three prior days’ runs

 

Compare to run from just 3 days ago:

After trending in the direction of increasing chance for midmonth major SSW the prior 3 days, today’s Euro Weeklies trended back the other way some. After yesterday’s +16 low for mid Feb, today’s only goes down to +20. This fits in with the GFS reversing course recently to a lowered chance.

 If there’s going to actually be one, a reversal of this reversal would be needed very soon.

[MJO812]

[Stormchaserchuck1]

End of the 12z GEFS run at Days 15-16 had Arctic blocking. That matches -EPO patterns

And is a cold pattern at the surface in the eastern 2/3 of the CONUS

Whether it verifies or not is another issue. Models have trended from predominantly -PNA pattern, to now -EPO in the last few days. 

[Stormchaserchuck1]

5800dm heights coming up for NW Russia in mid Winter!

Looks to be about a +600dm anomaly, which I think is record breaking

Loading area for -AO/-NAO later on.. let's see how that evolves/works out

[so_whats_happening]

I still do not understand why everyone is so hellbent on this being a SPV split or not. 

[so_whats_happening]

On 1/31/2025 at 12:38 AM, GaWx said:

 You may be onto something that I wasn’t paying attention to til just now when I saw this on the 0Z GFS 168 for Feb 7: check out the strength of this Scandinavian-Greenland Dipole! Is this what you were looking at yesterday?

 

 This paper was written by Dr. Simon Lee and others about the 2/12/2018 major SSW that was not forecasted beyond 12 days:

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JD030940

 He talks about a S-G Dipole pattern (strong high over Scand/low over Greenland) often being predictive of major SSWs before models actually do so (they’re still not). This dipole peaked ~2/6/2018, or only one day prior to the forecasted peak of ~2/7/25! Aside: the major SSW of 2/16/23 was also preceded by a similar early Feb S-G Dipole!

Dr. Lee’s latest tweets:

 

 Despite the models still not showing even a hint of a major SSW, I’ve been wary about it based on Joe D’Aleo’s study showing a heightened chance during high solar/+QBO. I took his idea and looked at the actual #s. I considered high solar for DJF to be 135+. DJ will be ~145. If Feb ends up 115+, it would qualify. Check this out:

 

Solar DJF 135+/west QBO:

57-8: SSW 1/31/58

59-60: SSW 1/17/60

69-70: SSW 1/2/70

78-9: SSW 2/22/79

80-1: SSW 2/6/81

90-1: no SSW

99-00: SSW 3/20/00

01-02: SSW  12/31/01, 2/18/02

 So, a whopping 7 of these 8 winters had at least one major SSW! Just food for thought. The progged strong Feb 7th S-G Dipole is consistent with a potential major SSW on or near Feb 13th if it were to actually occur with similar timing to 2018. If so, look for hints on the EPS/GEFS starting this weekend. IF there were to be one ~Feb 13th, look out for the potential of a colder E US pattern starting ~Feb 27th and lasting through at least ~Mar 15th and quite possibly the entire month or further. Anything to keep the bugs quiet would be a winning pattern for me!

 

Sorry for the late response I will have to take a look at the paper when I get a free chance then.

[Stormchaserchuck1]

34 minutes ago, so_whats_happening said:

I still do not understand why everyone is so hellbent on this being a SPV split or not. 

The actual anomalies is what matters.  Everything I've seen looks pretty neutral..