2024-2025 La Nina

[Stormchaserchuck1]

1 hour ago, GaWx said:

Thank you. But I don’t recall folks thinking that winter was cooked BEFORE it started.

These seasonal models do pretty good, as bluewave has been pointing out. They aren't perfect, but do generally get near the area right. Last Winter, for example, they had strong H5 warmth over NE Canada and the Davis Strait. It ended up being record warm in eastern Canada. Another example, Sometimes they will show warm over California, then it ends up being Arizona, etc.. 

The Euro currently is showing well below average snowfall to the Canadian border. For the Mid Atlantic and Southeast to have a below average temperature Winter with above average snowfall, the model would need to be near 180 degrees wrong. Because of just that, I would say it's probably 80% that the Mid Atlantic and Southeast have generally above average temperatures and below average snowfall. Obviously, temps are easier to nail then snowfall because 1 big storm or a few storms could make the difference. It's probably 85% temps, and 70% snowfall. 

[Stormchaserchuck1]

On 10/26/2024 at 8:01 AM, bluewave said:

If these preliminary daily AO values hold, then this will be the first 7+ sigma AO swing outside of the December to April period in around a month or less. The lowest reading back on 10-7-24 was -2.445 rising to +4.795 on 10-23 for a +7.240 sigma swing. 4 out of the top 5 greatest AO swings occurred since 2005. So this goes to how amplified  and volatile the AO index has become in recent years. 

Greatest AO swings on record in around a month or less since 1950 and the date on which the maximum difference from low to high or high to low occurred with the numerical value of the swing

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.daily.ao.nao.pna.aao.gdas.120days.csv

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

#1……+10.790……3-11-21

#2…...+9.401…….1-16-16

#3……+9.256……3-2-56

#4……+9.039……4-21-13

#5……+8.522……1-25-05
#6…...+8.462…..1-15-77

#7…….+8.268….3-16-68

#8…….+7.793….2-25-01

#9…….+7.731….3-23-86

#10……+7.720…2-4-11

#11……+7.641…..3-5-70

#12…..+7.502…..1-19-85

#13……+7.387….3-20-78

#14……+7.240….10-23-24

#15……+7117……1-23-52

#16…..+7.066…1-24-08

#17……+7.043…3-19-15

#18……+7.038…2-10-76

Previous occurrences: March, Jan, March, April, Jan, Jan, March, Feb, March, Feb, March, Jan, March, Jan, Jan, March, Feb

Mostly negative as the extreme reading. 

October 2024 - Positive

Could it have something to do with this? (photo I took)

Before the solar flares hit, the AO was not forecasted to go that positive. Just an interesting correlation. 

I would think if there would be an effect, it would be the Pole (AO). 

[GaWx]

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.

[Stormchaserchuck1]

Natural Gas December contract dropped 7% today, making its spread with Crude Oil/Gasoline the 2nd lowest on record, behind only last year (big +NAO or +EPO signal). 

[bluewave]

1 hour ago, Stormchaserchuck1 said:

Previous occurrences: March, Jan, March, April, Jan, Jan, March, Feb, March, Feb, March, Jan, March, Jan, Jan, March, Feb

Mostly negative as the extreme reading. 

October 2024 - Positive

Could it have something to do with this? (photo I took)

Before the solar flares hit, the AO was not forecasted to go that positive. Just an interesting correlation. 

I would think if there would be an effect, it would be the Pole (AO). 

I was looking more at the big burst of IO forcing which preceded the record breaking AO rise.

https://www.nature.com/articles/s41612-022-00279-x#:~:text=Arctic oscillation (AO)%2C which,the positive trend of AO.

Arctic oscillation (AO), which is the most dominant atmospheric variability in the Northern Hemisphere (NH) during the boreal winter, significantly affects the weather and climate at mid-to-high latitudes in the NH. Although a climate community has focused on a negative trend of AO in recent decades, the significant positive trend of AO over the last 60 years has not yet been thoroughly discussed. By analyzing reanalysis and Atmospheric Model Inter-comparison Project (AMIP) datasets with pacemaker experiments, we found that sea surface temperature warming in the Indian Ocean is conducive to the positive trend of AO from the late 1950s. The momentum flux convergence by stationary waves due to the Indian Ocean warming plays an important role in the positive trend of AO, which is characterized by a poleward shift of zonal-mean zonal winds. In addition, the reduced upward propagating wave activity flux over the North Pacific due to Indian Ocean warming also plays a role to strengthen the polar vortex, subsequently, it contributes to the positive trend of AO

[donsutherland1]

14 minutes ago, Stormchaserchuck1 said:

Natural Gas December contract dropped 7% today, making its spread with Crude Oil/Gasoline the 2nd lowest on record, behind only last year (big +NAO or +EPO signal). 

The market is reacting to the already warm guidance that has been growing even warmer for December.

[michsnowfreak]

On 10/27/2024 at 11:18 AM, GaWx said:

 Is it ever clearly a lost cause as of late Oct? I can’t remember a single late Oct when the winter was already determined to be a lost cause at this BB and any others. I don’t mean by any particular individual but rather based on the general consensus/discussion.

I've been on weather forums 22 years and my recollection is very different. 

Is it ever a lost cause in October? No.

Are there some who act like/say/imply it's a lost cause in October? Every single year. Without fail. Every single year.

[GaWx]

4 hours ago, michsnowfreak said:

I've been on weather forums 22 years and my recollection is very different. 

Is it ever a lost cause in October? No.

Are there some who act like/say/imply it's a lost cause in October? Every single year. Without fail. Every single year.

 I agree there are some individuals who say that every year, but I’m talking about the general tone amongst the active posters during October. There are certain posters who are pessimistic on a semi-regular to regular basis. They are often doing that for trolling purposes though not all.

 I’ve found the general tone to be more optimistic than the models would suggest quite often. But that makes sense because in advance of winter many wx enthusiasts have had tendencies to be optimistic/hopeful. It is natural.

 I’m still not recalling a single autumn with a dominant pessimistic tone for winter. But if anyone can point to one, I’d like to know about it. It wasn’t 2001-2 for the reasons I stated. I’d say this autumn is the closest but even it has had some level of hope/optimism just like I’m claiming is the case every October, which is what got me talking about this.

 You said: “Is it ever a lost cause in October? No.”

 That is my main point. So I think we actually agree.

[michsnowfreak]

15 minutes ago, GaWx said:

 I agree there are some individuals who say that every year, but I’m talking about the general tone amongst the active posters during October. There are certain posters who are pessimistic on a semi-regular to regular basis. They are often doing that for trolling purposes though not all.

 I’ve found the general tone to be more optimistic than the models would suggest quite often. But that makes sense because in advance of winter many wx enthusiasts have had tendencies to be optimistic/hopeful. It is natural.

 I’m still not recalling a single autumn with a dominant pessimistic tone for winter. But it anyone can point to one, I’d like to know about it. It wasn’t 2001-2 for the reasons I stated. I’d say this autumn is the closest but even it has had some level of hope/optimism just like I’m claiming is the case every October, which is what got me talking about this.

 You said: “Is it ever a lost cause in October? No.”

 That is my main point. So I think we actually agree.

Ah that explains it. We do agree then. It comes from certain individuals on a yearly basis. As for overall tone, I really wouldn't say the overall tone is full dread. Maybe a bit jaded, but the true dreaded tone is from a few of the usual individuals. As has been said many times by me and others, the upper midwest, Great Lakes and northern New England will probably have a good snow season. South of NYC doesn't look so good, but even there you can absolutely get a few good storms. And they never should expect sustained winter anyway. So really, no reason for doom in October. 

[roardog]

2 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.

Verbatim it has a varying depth of trough west/ridge east pattern but it also has ridging into Alaska for most of the run. So regardless of what the useless 2M temp anomalies show, there would be arctic air in Canada in that situation which could at least make things interesting for northerners like me. It actually has some very cold 850 anomalies in the western half of the US. 

[GaWx]

2 hours ago, roardog said:

Verbatim it has a varying depth of trough west/ridge east pattern but it also has ridging into Alaska for most of the run. So regardless of what the useless 2M temp anomalies show, there would be arctic air in Canada in that situation which could at least make things interesting for northerners like me. It actually has some very cold 850 anomalies in the western half of the US. 

Yeah, you being where you are could help at times more than those to your SE (assuming these are accurate of course).

 During weeks 3-6 the mean shows AN H5 hts dominating in/near the Aleutians, which typically teleconnects to AN H5 dominating in much of the E US (-PNA), especially Mid-Atlantic S. I like to see the opposite,  BN/troughing dominating in the Aleutians, which is common during El Niño, since it typically teleconnects to BN hts dominating as +PNA is favored. Week 3 is below:

[Typhoon Tip]

4 hours ago, bluewave said:

I was looking more at the big burst of IO forcing which preceded the record breaking AO rise.

https://www.nature.com/articles/s41612-022-00279-x#:~:text=Arctic oscillation (AO)%2C which,the positive trend of AO.

Arctic oscillation (AO), which is the most dominant atmospheric variability in the Northern Hemisphere (NH) during the boreal winter, significantly affects the weather and climate at mid-to-high latitudes in the NH. Although a climate community has focused on a negative trend of AO in recent decades, the significant positive trend of AO over the last 60 years has not yet been thoroughly discussed. By analyzing reanalysis and Atmospheric Model Inter-comparison Project (AMIP) datasets with pacemaker experiments, we found that sea surface temperature warming in the Indian Ocean is conducive to the positive trend of AO from the late 1950s. The momentum flux convergence by stationary waves due to the Indian Ocean warming plays an important role in the positive trend of AO, which is characterized by a poleward shift of zonal-mean zonal winds. In addition, the reduced upward propagating wave activity flux over the North Pacific due to Indian Ocean warming also plays a role to strengthen the polar vortex, subsequently, it contributes to the positive trend of AO

I think the science would find that the polarward shift in the zonal-mean zonal wind is occurring in both hemispheres everywhere …

[Typhoon Tip]

impressively persistent -pnap extending through the 1st 2 weeks of nov in guidance 

pure experience … novies tend to be low amplitude +pnap. interesting 

[George001]

5 hours ago, michsnowfreak said:

I've been on weather forums 22 years and my recollection is very different. 

Is it ever a lost cause in October? No.

Are there some who act like/say/imply it's a lost cause in October? Every single year. Without fail. Every single year.

The only exception to this would be when an extremely potent Nino is imminent. I know what the seasonal guidance is saying, but I’ll take my chances with the way things look now any day over how they looked last year in mid to late fall.

[George001]

5 hours ago, michsnowfreak said:

Ah that explains it. We do agree then. It comes from certain individuals on a yearly basis. As for overall tone, I really wouldn't say the overall tone is full dread. Maybe a bit jaded, but the true dreaded tone is from a few of the usual individuals. As has been said many times by me and others, the upper midwest, Great Lakes and northern New England will probably have a good snow season. South of NYC doesn't look so good, but even there you can absolutely get a few good storms. And they never should expect sustained winter anyway. So really, no reason for doom in October. 

I’m feeling pretty good about things where I’m at near Boston

[michsnowfreak]

4 hours ago, roardog said:

Verbatim it has a varying depth of trough west/ridge east pattern but it also has ridging into Alaska for most of the run. So regardless of what the useless 2M temp anomalies show, there would be arctic air in Canada in that situation which could at least make things interesting for northerners like me. It actually has some very cold 850 anomalies in the western half of the US. 

Great point! The cold in Canada, which is pretty much agreed upon on seasonal models, is very important as we go through winter. I say this every year for us (and anyone else north of 40N), don't let the reds and orange departures on longrange maps get too in your head without thinking about the overall pattern. It's a cold climate, precip SHOULD be plentiful, so no reason to think it won't be a serviceable winter. Is this 2007-15? Absolutely not. But it's no 2023-24 either.

[michsnowfreak]

31 minutes ago, George001 said:

I’m feeling pretty good about things where I’m at near Boston

I think you are good too. If a gradient pattern develops, Massachusetts may do very well. Sometimes you have to sniff the rain to get the best snows. 

[snowman19]

13 hours ago, Stormchaserchuck1 said:

Natural Gas December contract dropped 7% today, making its spread with Crude Oil/Gasoline the 2nd lowest on record, behind only last year (big +NAO or +EPO signal). 

November is starting to look more and more like a torch and not only a torch, continued very dry/drought as well. Also on a side note, just eyeballing the QBO anomalies, it’s definitely still strengthening positive

[bluewave]

On 10/27/2024 at 11:18 AM, GaWx said:

 Is it ever clearly a lost cause as of late Oct? I can’t remember a single late Oct when the winter was already determined to be a lost cause at this BB and any others. I don’t mean by any particular individual but rather based on the general consensus/discussion.

I will take it a step further than that and say whether for positive or negative the winter outcomes can be traced back as early as the previous spring or summer. The record breaking warmth and ridging last winter in Canada was becoming evident in May 2023 which carried right through last winter. The 22-23 winter deep trough in the West pattern became established in November. The very strong SPV pattern in 19-20 began with the near record IOD and IO forcing in the fall. The cold and snowy 13-14 and 14-15 winter patterns first began to set up with the record TNH during the summer of 2013. The great backloaded 12-13 progression followed the early peaking El Niño around Labor Day even though no official Nino was declared. The amazing 09-10 and 10-11 blocking patterns first became evident in the summer of 2009 with one of the coolest June and July periods around NYC and record summer blocking.

[40/70 Benchmark]

1 hour ago, bluewave said:

I will take it a step further than that and say whether for positive or negative the winter outcomes can be traced back as early as the previous spring or summer. The record breaking warmth and ridging last winter in Canada was becoming evident in May 2023 which carried right through last winter. The 22-23 winter deep trough in the West pattern became established in November. The very strong SPV pattern in 19-20 began with the near record IOD and IO forcing in the fall. The cold and snowy 13-14 and 14-15 winter patterns first began to set up with the record TNH during the summer of 2013. The great backloaded 12-13 progression followed the early peaking El Niño around Labor Day even though no official Nino was declared. The amazing 09-10 and 10-11 blocking patterns first became evident in the summer of 2009 with one of the coolest June and July periods around NYC and record summer blocking.

Its easy to say that in hindsight, but those largescale patterns don't always lock into place. The key is knowing when they will and which ones to key in on.

[bluewave]

23 minutes ago, 40/70 Benchmark said:

It’s easy to say that in hindsight, but those largescale patterns don't always lock into place. The key is knowing when they will and which ones to key in on.

The key is figuring out where the mean ridge and trough locations will play out. Then adjusting the mean ridge locations warmer than the seasonal guidance since they have had a cold bias where the strongest ridges actually have set up in recent years. I was pointing out last year in the El Niño thread early on how the models were probably overdoing that Nino trough in the East due to the La Niña background through the record WPAC warm pool which serves to enhance the Southeast Ridge. Then the discussions about the record warmth in Canada since May 2023 as a precursor to the winter. So last winter was one of the easier to see how the model cold biases would play out. While I agree we could see the risk of a warmer scenario last winter early on, the exact magnitude of the departures took until those +10 to +15 Canadian departures showed up for December during the first week of month. 

[40/70 Benchmark]

21 minutes ago, bluewave said:

The key is figuring out where the mean ridge and trough locations will play out. Then adjusting the mean ridge locations warmer than the seasonal guidance since they have had a cold bias where the strongest ridges actually have set up in recent years. I was pointing out last year in the El Niño thread early on how the models were probably overdoing that Nino trough in the East due to the La Niña background through the record WPAC warm pool which serves to enhance the Southeast Ridge. Then the discussions about the record warmth in Canada since May 2023 as a precursor to the winter. So last winter was one of the easier to see how the model cold biases would play out. While I agree we could see the risk of a warmer scenario last winter early on, the exact magnitude of the departures took until those +10 to +15 Canadian departures showed up for December during the first week of month. 

O

[40/70 Benchmark]

I guess the hope this year is that the mean ridge location is actually a bit WSW of us this year....have seen some hints of that in seasonal guidance.

[PhiEaglesfan712]

25 minutes ago, bluewave said:

Then the discussions about the record warmth in Canada since May 2023 as a precursor to the winter. So last winter was one of the easier to see how the model cold biases would play out. While I agree we could see the risk of a warmer scenario last winter early on, the exact magnitude of the departures took until those +10 to +15 Canadian departures showed up for December during the first week of month. 

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.

[bluewave]

20 minutes ago, 40/70 Benchmark said:

O

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. 

[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.