2024-2025 La Nina

[FPizz]

16 hours ago, GaWx said:

Euro Weeklies means are mainly mild in the E US through the entire run (goes through Dec 9th) fwiw. Consistent with that, the mean SPV (thick blue line) (climo is thick red line) is very strong through Dec 12th. If this verifies, JB is going to have a very hard time getting the cold Dec he keeps mentioning.

Roll this back a 45 days and compare to now, how did it do? 

[40/70 Benchmark]

38 minutes ago, bluewave said:

Like we were discussing the other day, we are really going to need a mismatch this winter in order to push back against so many early warm signals. On one hand we have the divergence that we haven’t seen since 2010 with the Niña strength and early MJO. If the weaker La Niña past winter patterns win out than the main ridge axis spot has a shot a more very high temperature departures since the weaker La Ninas have been warmest since 2010. The early hints are that it will be further south than last winter. But the early MJO indicator is following the stronger path like 20-21. Due to the divergence I don’t know yet whether it will continue to work. My guess is when we get to the early December modeling timeframe one or the other scenarios should be obvious at that time. So like many times we have to wait until the first week of December to see which way the pattern moves. 

Canada def. won't be as warm as last season because that "El Nina" configuration was a perfect storm for that, so by default much of the nothern US should be a bit cooler...even NE.

[BlizzardWx]

Like some others noted, I have also seen a loose correlation between warm season patterns and the eventual winter outcome. It's never in the exact same place and the amplitudes change (etc.) but usually there are hints of what will eventually occur. Here is what we had for April to August. Obviously the pattern that developed since then has been very different but maybe this map will still have some seasonal forecasting utility. 

[bluewave]

48 minutes ago, PhiEaglesfan712 said:

Which part of Canada? Was it the West? Because I'm pretty sure it wasn't anywhere in Eastern Canada because here in the mid-Atlantic, we got one of our coolest May-June periods ever, and an overall cool summer. May/June was dominated by a blocking pattern that caused the smoky orange skies in NYC/mid-Atlantic in June 2023.

Canada had their strongest May 500mb ridge on record in 2023. Then the ridge axis shifted a bit ESE for the winter. The La Niña background combined with the El Niño allowing more ridging than we typically see in the East during El Niños. I was pointing out the potential error that the Euro seasonal forecast was showing last fall in the East. 
 

[40/70 Benchmark]

On 8/14/2024 at 10:49 PM, Stormchaserchuck1 said:

So.. we had a record N. American ridge December 2023 through August 3rd. 

I went through the entire dataset, and found 20 top analog, which matched the signal general:

Here's what they look like rolled-forward...

November:

December:

January:

February:
 

Nov-Feb Total:

The February map having +5-6F temps for 20 analogs (+ and -), 20/75 of the whole dataset is pretty strong. You can see the progression into a SE ridge historically. 

 

On 10/24/2024 at 5:09 PM, donsutherland1 said:

The latest CFSv2 forecast for November indicates that most of the CONUS will be warmer than normal.

Thus, the question becomes what kind of winter would be likely to follow such a November. With the December 2024-February 2025 Relative ENSO Region 3.4 Index (RONI) likely to average -0.500 or below, it makes some sense to examine how CONUS  winters have fared in the past with winter values of -0.500 or below following widespread November warmth in the CONUS (1951-2010 baseline) since 1949-50.

The Composite Temperature Anomalies for North America (1991-2020 baseline, as the larger period was not available) were as follows:

November:

December-February:

The most recent C3S Multi-Ensemble Forecast for December 2024-2025:

It should be noted that even warm winters have often seen periods of cold. In cases, there have been some periods of severe cold.

Overall, the forecast winter anomalies are reasonably in line with those that have followed the kind of November that is forecast when the winter RONI averaged -0.500 or below.

 

 

Some similarities with respect to winter in these analog packages.

[40/70 Benchmark]

On 8/4/2024 at 5:29 PM, Typhoon Tip said:

I know what's your getting at and don't disagree at a granular level but there are ways in which -PNA/+NAO becomes a problem from the Great Lakes to the upper mid Atlantic and New E regions.   

The simplest way to describe that model is an episodic retrograde of a NW-SE Canadian deep layer conveyor, one that sets up around a big eastern Canadian SPV, which becomes a positive NAO derivative.   But importantly, that sets stage with presage cold loading, prior to RNA sending impulses E ... Storms are flat wave over-runners.  

+EPO ... yeah, that's a tougher sell.

Kind of like Dec 2007 and 2008...

[Typhoon Tip]

I wonder if Fuji snow is correlating with the wpac warm anomaly 

“Japan’s iconic Mount Fuji has yet to see snow this season, breaking a 130-year record” -cnn

[Maestrobjwa]

1 minute ago, Typhoon Tip said:

I wonder if Fuji snow is correlating with the wpac warm anomaly 

“Japan’s iconic Mount Fuji has yet to see snow this season, breaking a 130-year record” -cnn

Hasn't there been a warm anomaly there the last few winters? Seems like I've seen "wpac warm pool" a lot...

[Typhoon Tip]

5 minutes ago, Maestrobjwa said:

Hasn't there been a warm anomaly there the last few winters? Seems like I've seen "wpac warm pool" a lot...

yeah .. kinda why i was careful to use ‘correlating’   as in ongoing. implicitly, maybe since the warm anomaly showed up there’s also a surrounding atmospheric echo 

[snowman19]

@GaWx 

Just looking at the anomalies, the QBO is clearly still strengthening. Last month’s number was +12 and I believe the strongest westerly/positive QBO on record at 30mb was over +15. Wondering if we may rival or top that?

[bluewave]

The record breaking 500mb ridge which was up in Canada since last year dropped south in October with the La Niña and shut off the rainfall for much of the U.S.

 

 

[snowman19]

The record breaking 500mb ridge which was up in Canada since last year dropped south in October with the La Niña and shut off the rainfall for much of the U.S.




 
 

[FPizz]

13 hours ago, Typhoon Tip said:

I wonder if Fuji snow is correlating with the wpac warm anomaly 

“Japan’s iconic Mount Fuji has yet to see snow this season, breaking a 130-year record” -cnn

But Hawaii has gotten snow, so it evens out lol

[bluewave]

1 hour ago, snowman19 said:

 

 

Yeah, the PAC Jet shift  to the north has really dried things out across the U.S. this month.

 

[Typhoon Tip]

partially agree. 

not sure the exact physical/causal root of the current distribution of anomalies of the hemispheric-scaled atmosphere can be 'directly' attributable to the pac sst observation like that.  

as i've mentioned before, and most credible sources know this to be true ... there is a longer termed, quasi coupled relationship between the ss stressing wind patterns, and sst anomaly distribution in the top most layer.   it's an emergent state due to persistence in that relationship.

it may in fact be more useful (indirect) as a means to expose where those stressing tendencies have been ...and from that, work backward ( so to speak) in determining the basal pattern construct(s).  so that's the partial agreeing for me.

i think there may be a slight and/or growing kind of misconception that these so called 'marine heat waves' have a spontaneity to their arrival, that the atmosphere is then motivated by their occurrence.  it's plausibly imaginative to suspect there may be feed-backs later on, as the thermal sources perhap breach some thermodynamic (bulk) threshold.

 

[bluewave]

6 minutes ago, Typhoon Tip said:

partially agree. 

not sure the exact physical/causal root of the current distribution of anomalies of the hemispheric-scaled atmosphere can be 'directly' attributable to the pac sst observation like that.  

as i've mentioned before, and most credible sources know this to be true ... there is a longer termed, quasi coupled relationship between the ss stressing wind patterns, and sst anomaly distribution in the top most layer.   it's an emergent state due to persistence in that relationship.

it may in fact be more useful (indirect) as a means to expose where those stressing tendencies have been ...and from that, work backward ( so to speak) in determining the basal pattern construct(s).  so that's the partial agreeing for me.

 

The composites this month matched a much stronger MJO 6 in the means than we have seen in any other past October. So my guess is that we are getting enhanced SST feedback east of Japan. When this combined with the background Maritime Continent forcing it resulted in an unusually strong standing wave pattern for October.

[Typhoon Tip]

4 hours ago, bluewave said:

The composites this month matched a much stronger MJO 6 in the means than we have seen in any other past October. So my guess is that we are getting enhanced SST feedback east of Japan. When this combined with the background Maritime Continent forcing it resulted in an unusually strong standing wave pattern for October.

yeah, i added a late edit to that op ed there...

not you or any one in particular, but i do suspect there is a growing kind of misconception related to so called 'marine heat waves' forcing patterns.  almost like they have a spontaneity to their arrival, ...then the atmosphere is motivated by their occurrence.  mm not really.  but in fairness, i may be assigning that fallacy - it just comes off/"seems" like the former notion is lurking when these tweets or x's or whatever are re-posting about target causes like that.

it's plausibly imaginative to suspect there may be feed-backs later on, as the thermal sources perhap breach some thermodynamic (bulk) threshold.  but the ocean, particularly at middle latitude mixing circumstance ... isn't realistically going to just burst a thermal resonance out of nowhere, whereby we can conveniently find a silver bullet there. 

[bluewave]

23 minutes ago, Typhoon Tip said:

yeah, i added a late edit to that op ed there...

not you or any one in particular, but i do suspect there is a growing kind of misconception related to so called 'marine heat waves' forcing patterns.  almost like they have a spontaneity to their arrival, ...then the atmosphere is motivated by their occurrence.  mm not really.  but in fairness, i may be assigning that fallacy - it "seems" like the former notion is lurking when these tweets or x's or whatever are re-posting about target causes like that.

it's plausibly imaginative to suspect there may be feed-backs later on, as the thermal sources perhap breach some thermodynamic (bulk) threshold.  but the ocean, particularly at middle latitude mixing circumstance ... isn't realistically going to just burst a thermal resonance out of nowhere, whereby we can conveniently find a silver bullet there. 

Yeah, the magnitude of the 500mb anomalies are off the charts for what would have been past occasions of forcing lining up over the WPAC.

 

 

[40/70 Benchmark]

5 hours ago, bluewave said:

The record breaking 500mb ridge which was up in Canada since last year dropped south in October with the La Niña and shut off the rainfall for much of the U.S.

 

 

It now aligns with where a lot of the seasonals have the warmth centered this winter....in the N plains.....wonder if cold from Canada may be abit more accessible to the NE relative to last year.

[LakeEffectOH]

5 hours ago, snowman19 said:

 

 

Does anyone have some idea as to what's causing this marine heatwave?

[40/70 Benchmark]

7 minutes ago, LakeEffectOH said:

Does anyone have some idea as to what's causing this marine heatwave?

Combo of powerful Pacific cold phase and CC.

[George001]

8 hours ago, bluewave said:

The record breaking 500mb ridge which was up in Canada since last year dropped south in October with the La Niña and shut off the rainfall for much of the U.S.

 

 

What are your thoughts on the plains centered warmth? It has been warm and dry everywhere but the real torch has been plains centered. The seasonal guidance is warm in November but with a similar theme to the past 90 day temp profile. Based on the fall temp profile and weak ENSO, I’m actually inclined to think that the risk is colder/snowier rather than warmer than the seasonal guidance based on this, especially if we do get periods of -EPO. Getting enough -EPO to result in a BN temp winter with a -3 PDO is an extremely tough ask especially with CC so I wouldn’t outright forecast it, but it’s something in the back of my mind. I’m thinking +2 to +3 AN temps for my area, but I do think there is say a ~20% chance that cold bleeds into the east and just about everyone busts way too warm. I am nowhere near as confident as I was last fall in a torch winter.

[bluewave]

59 minutes ago, George001 said:

What are your thoughts on the plains centered warmth? It has been warm and dry everywhere but the real torch has been plains centered. The seasonal guidance is warm in November but with a similar theme to the past 90 day temp profile. Based on the fall temp profile and weak ENSO, I’m actually inclined to think that the risk is colder/snowier rather than warmer than the seasonal guidance based on this, especially if we do get periods of -EPO. Getting enough -EPO to result in a BN temp winter with a -3 PDO is an extremely tough ask especially with CC so I wouldn’t outright forecast it, but it’s something in the back of my mind. I’m thinking +2 to +3 AN temps for my area, but I do think there is say a ~20% chance that cold bleeds into the east and just about everyone busts way too warm. I am nowhere near as confident as I was last fall in a torch winter.

I am thinking we are going to have to wait until the first week of December to know since the forcing leading to these standing wave patterns can result in the main 500mb height anomaly shifting locations depending on the month. 

[roardog]

I'd be stunned if the northern plains were the center of warmth this winter. If the northern plains is the center of warmth this winter during a Nina, then we're probably all screwed.

[SethToast]

Are any seasonal models even showing warm N plains beyond mid-December? 

[michsnowfreak]

1 hour ago, roardog said:

I'd be stunned if the northern plains were the center of warmth this winter. If the northern plains is the center of warmth this winter during a Nina, then we're probably all screwed.

 

1 hour ago, SethToast said:

Are any seasonal models even showing warm N plains beyond mid-December? 

I'm assuming George misspoke. The northern plains are the center of late october/early November warmth, but will quite likely be some of the colder anomalies this winter. Nearly all models show this to one extent or another, and it's definitely nina climo to boot.

[snowman19]

[George001]

2 hours ago, michsnowfreak said:

 

I'm assuming George misspoke. The northern plains are the center of late october/early November warmth, but will quite likely be some of the colder anomalies this winter. Nearly all models show this to one extent or another, and it's definitely nina climo to boot.

Yeah my post was kind of misleading, my bad on that. From what I have seen the guidance does have the warmth in the northern plains continuing into December, but yeah it should be much colder there in the winter. The main point I was making is that the fall pattern is completely different than the last 2 years, and when looking at winters with a similar temp/precip profile in the fall, there are some colder/snowier years in the mix. I mean a lot colder and snowier, like 13-14 and 10-11. I did not mean to imply that the northern plains would roast all winter with a strong +PNA, that would be a 14-15 type pattern. November was frigid in the east from what I remember and it was a warm ENSO pattern, so not a good analog at all. In 13-14 and 10-11, the plains was cold. In 13-14 in particular the plains was downright frigid, though the cold did bleed into the east as well. Of course, there were some really bad winters like 01-02 in there as well which is also a possibility. 

[SnoSki14]

1 hour ago, snowman19 said:

 

 

 

 

 

What a disaster. Dust bowl 2.0

[CheeselandSkies]

Quote

This will also probably extend into winter, though the jet intensity may increase over the northern U.S., leading to a more unsettled regime for much of the northern tier of states.

(From the earlier linked tweet Xpost by Ben Noll)

I wonder if that could lead to more December central U.S. outbreaks a la 2021 (12/10, 12/15). Although interestingly we also had some in 2015 (12/23, 12/26) which was during the powerhouse El Nino. James Spann referred to the mild conditions across the southeast US during that period as the "El Nino Blowtorch," although it seems to me that pattern is also associated with La Nina.