2024-2025 La Nina

[BuffaloWeather]

The pattern coming up looks incredible, so many wintry chances. The lakes are going to be firing the first week of December.

[GaWx]

0Z GEFS and EPS at least appear to be the coldest runs yet for the E US! NG is once again at new highs (up 3%), highest since Jan.

[snowman19]

4 hours ago, GaWx said:

0Z GEFS and EPS at least appear to be the coldest runs yet for the E US! NG is once again at new highs (up 3%), highest since Jan.

It’s becoming clear that the massive WWB no one expected, which turned ENSO region 1+2 into an El Niño had huge effects on the Rossby wave train, spiked the AAM positive and completely altered the long wave synoptic pattern. It changed the entire 500mb in the North Pacific (-WPO, -EPO, +PNA). The retrograding -NAO was happening regardless, totally different forcing mechanism with that. Now the million dollar question is did this start the beginning of a legit long term big shift North Pacific pattern for this winter or is this a temporary flux? No one is going to have the answer until we are into December. The models still show a big trade wind burst in region 3.4 in December, but will it actually matter at that point? Once the -NAO block dissipates, it’s going to be a purely PAC driven cold pattern, i.e. 13-14….does it continue??

[bluewave]

It’s been a long time since we saw a 15 day swing in this direction for an early December forecast. But I will give the models credit for seeing the Aleutian Ridge shift north of the Aleutians. If the forecasts are still showing this type of shift from the recent years in early December, then the December 5th Euro seasonal update should look different from what it had on November 5th. 
 

New run

Old run

Dominant 500 mb pattern in December since 2015 with ridge south of Aleutians rather than north

 

 

[PhiEaglesfan712]

The MEI has been updated. AS was -0.6 and SO was -0.5

I certainly wasn't expecting that, but the la nina is cooked. (Although we got an offical weak la nina on the MEI.)

[bluewave]

23 minutes ago, snowman19 said:

It’s becoming clear that the massive WWB no one expected, which turned ENSO region 1+2 into an El Niño had huge effects on the Rossby wave train, spiked the AAM positive and completely altered the long wave synoptic pattern. It changed the entire 500mb in the North Pacific (-WPO, -EPO, +PNA). The retrograding -NAO was happening regardless, totally different forcing mechanism with that. Now the million dollar question is did this start the beginning of a legit long term big shift North Pacific pattern for this winter or is this a temporary flux? No one is going to have the answer until we are into December. The models still show a big trade wind burst in region 3.4 in December, but will it actually matter at that point? Once the -NAO block dissipates, it’s going to be a purely PAC driven cold pattern, i.e. 13-14….does it continue??

The even bigger question is are we a least starting to see a small shift in the PCC? Remember how the El Niño last year began with the record 1+2 warming so early on with that record late winter 2023 WWB which was so east based. This most recent WWB was shifted over to the EPAC also. Maybe this means that at least for shorter intervals the EPAC can have more influence at times than the WPAC warm pool and MJO 4-7 has had since December 2015. It’s also possible that the big jump in global temperatures since 2023 is related to changes in the EPAC near South America. But it’s probably too early to speculate on that until we get more data.

 

https://www.nature.com/articles/s41467-024-52731-6

The eastern tropical Pacific has defied the global warming trend. There has been a debate about whether this observed trend is forced or natural (i.e., the Interdecadal Pacific Oscillation; IPO) and this study shows that there are two patterns, one that oscillates along with the IPO, and one that is emerging since the mid-1950s, herein called the Pacific Climate Change (PCC) pattern. 

 

As the tropical Pacific is known to be a climatic pacemaker, for (at least) the near-future this would mitigate global warming via ocean heat uptake and low-level cloud feedbacks. Instead, if the cyclic IPO dominates the recent cooling, we may expect a strong warming when it reverses.

 

[mitchnick]

48 minutes ago, bluewave said:

It’s been a long time since we saw a 15 day swing in this direction for an early December forecast. But I will give the models credit for seeing the Aleutian Ridge shift north of the Aleutians. If the forecasts are still showing this type of shift from the recent years in early December, then the December 5th Euro seasonal update should look different from what it had on November 5th. 
 

New run

Old run

Dominant 500 mb pattern in December since 2015 with ridge south of Aleutians rather than north

 

 

Interesting. Maybe the next question, assuming we see the same look in early December, is whether we should bother caring what the seasonal models say. Idk. Both the Euro and Cfs2 weeklies just caught on to the cold pattern yesterday. 

[40/70 Benchmark]

49 minutes ago, PhiEaglesfan712 said:

The MEI has been updated. AS was -0.6 and SO was -0.5

I certainly wasn't expecting that, but the la nina is cooked. (Although we got an offical weak la nina on the MEI.)

I thought it would be like 0.9...wow.

[40/70 Benchmark]

10 hours ago, BuffaloWeather said:

Euro is still the king based on recent data.

Operational runs

Ensembles

 

Other guidance has simply closed the gap, which is causing some overreactions.

[40/70 Benchmark]

17 hours ago, 40/70 Benchmark said:

I appreciate the objectivity in the flavor of your posts.....whereas the knock on some of the guys in here is that they only report data that caters to perceived bias.

 

13 hours ago, bluewave said:

It’s possible that we are seeing the early stages of some type of 500 mb regime shift in the North Pacific. The ridge today in the Bering Sea has exceeded a +500 meter anomaly which is one of the strongest on record for this time of year. SST indices like the PDO are usually lagging indicators after the 500mb pattern gets stuck in place for a long enough period of time. For the 2020s so far the North Pacific Ridge has been anchored to the south of the Aleutians. So if the pattern can persist past the first week of December it’s possible that something significant shifted with this +AAM rise and WWB which caused the Nino 1+2s to warm off of South America. 

Near record 500 MB heights today Bering Sea 

 

2020s mean ridge south of Aleutians

 

 

12 hours ago, bluewave said:

This will probably be the first time in the last few years that a week 2 forecast trended colder instead of warmer.

New run

 

Old run

 

 

 

 

[40/70 Benchmark]

36 minutes ago, bluewave said:

The even bigger question is are we a least starting to see a small shift in the PCC? Remember how the El Niño last year began with the record 1+2 warming so early on with that record late winter 2023 WWB which was so east based. This most recent WWB was shifted over to the EPAC also. Maybe this means that at least for shorter intervals the EPAC can have more influence at times than the WPAC warm pool and MJO 4-7 has had since December 2015. It’s also possible that the big jump in global temperatures since 2023 is related to changes in the EPAC near South America. But it’s probably too early to speculate on that until we get more data.

 

https://www.nature.com/articles/s41467-024-52731-6

The eastern tropical Pacific has defied the global warming trend. There has been a debate about whether this observed trend is forced or natural (i.e., the Interdecadal Pacific Oscillation; IPO) and this study shows that there are two patterns, one that oscillates along with the IPO, and one that is emerging since the mid-1950s, herein called the Pacific Climate Change (PCC) pattern. 

 

As the tropical Pacific is known to be a climatic pacemaker, for (at least) the near-future this would mitigate global warming via ocean heat uptake and low-level cloud feedbacks. Instead, if the cyclic IPO dominates the recent cooling, we may expect a strong warming when it reverses.

 

I have always maintained that the globe will ultimately find a means of achieving some semblance of balance.

[40/70 Benchmark]

1 hour ago, snowman19 said:

It’s becoming clear that the massive WWB no one expected, which turned ENSO region 1+2 into an El Niño had huge effects on the Rossby wave train, spiked the AAM positive and completely altered the long wave synoptic pattern. It changed the entire 500mb in the North Pacific (-WPO, -EPO, +PNA). The retrograding -NAO was happening regardless, totally different forcing mechanism with that. Now the million dollar question is did this start the beginning of a legit long term big shift North Pacific pattern for this winter or is this a temporary flux? No one is going to have the answer until we are into December. The models still show a big trade wind burst in region 3.4 in December, but will it actually matter at that point? Once the -NAO block dissipates, it’s going to be a purely PAC driven cold pattern, i.e. 13-14….does it continue??

If it does continue, then my December forecast is cooked every bit as much as the past couple of winters.

[bluewave]

25 minutes ago, mitchnick said:

Interesting. Maybe the next question, assuming we see the same look in early December, is whether we should bother caring what the seasonal models say. Idk. Both the Euro and Cfs2 weeklies just caught on to the cold pattern yesterday. 

The seasonal models like the Euro can be pretty good during the first month they are initialized in. But the 2nd and 3rd months can be very different from the forecasts. This is why the Euro December 5th update for the month of December is usually more reliable than the one issued on November 5th. Go back and look at how much variation there has been from the seasonal model forecasts issued in November. 

[mitchnick]

11 hours ago, BuffaloWeather said:

Euro is still the king based on recent data.

Operational runs

Ensembles

 

Those comparisons are from 1 point in time, 120 hours out. A lot can go wrong with a forecast 5 days out with any or all of them. I  "think" I recall seeing a comparison less than 120 hours out and there was a marked unification of all the model forecasts as would be expected.  

Personally, with all the things that can and do go wrong with forecasts, I think this is one of those things (best model) that rests with anecdotal evidence as flawed as that may often be. I  mean we all can probably agree that the Euro used to be the best model based on our experience, but can likewise all agree now that it is not as good as it was based on experience. Jmho

[bluewave]

8 minutes ago, mitchnick said:

Those comparisons are from 1 point in time, 120 hours out. A lot can go wrong with a forecast 5 days out with any or all of them. I  "think" I recall seeing a comparison less than 120 hours out and there was a marked unification of all the model forecasts as would be expected.  

Personally, with all the things that can and do go wrong with forecasts, I think this is one of those things (best model) that rests with anecdotal evidence as flawed as that may often be. I  mean we all can probably agree that the Euro used to be the best model based on our experience, but can likewise all agree now that it is not as good as it was based on experience. Jmho

The metric we all want to see from one of those skill charts is how the models rank with storm system forecasts in the Eastern US. But they don’t keep track of that data as far as I can tell. So while the broad skill scores have value, they may not translate very well into which model has the most accurate storm tracks in our area. It could just be that the interaction of continental air masses with the multiple mountain ranges and the Gulf Stream causes long range storm track skill to vary from the those average 500 mb charts.

[PhiEaglesfan712]

12 hours ago, Stormchaserchuck1 said:

Now the 1st week of December looks cold. -WPO develops tonight, and holds through the next 15 days on 18z GFS ensembles.. -WPO patterns don't look that cold in the H5 means, but on the surface they are solidly below average.  If we are going to have a decent -WPO, I would actually watch for a snowstorm threat when the -NAO is coming up to near 0. A lot of research has been done correlating the rising-out-of-strong-negative NAO state with East Coast snowstorms, and if the Pacific pattern is favorable, there could really be a snowstorm threat, at least north of DC. Watch for around Thanksgiving, or a few days after. 

I'm particularly looking at December 2-4 here in the Philly area.

[bluewave]

13 hours ago, Stormchaserchuck1 said:

Now the 1st week of December looks cold. -WPO develops tonight, and holds through the next 15 days on 18z GFS ensembles.. -WPO patterns don't look that cold in the H5 means, but on the surface they are solidly below average.  If we are going to have a decent -WPO, I would actually watch for a snowstorm threat when the -NAO is coming up to near 0. A lot of research has been done correlating the rising-out-of-strong-negative NAO state with East Coast snowstorms, and if the Pacific pattern is favorable, there could really be a snowstorm threat, at least north of DC. Watch for around Thanksgiving, or a few days after. 

The thing to watch is where the storm track sets up. While the models ave been correcting stronger with the ridge over the Bering Sea into the first week of December, they still have a robust MJO wave running through 4-6. So even if it’s not the dominant factor it can still influence the storm tracks. If it’s strong enough the lows could run close to or just inland from I-95. Then the cold we see on the week 2 means could come in behind any lows rather than in front of them. If the storm tracks are still too warm for the coast, then will know the MJO is still exerting some influence. Should the storm tracks slide east then we’ll know the block near Alaska won out. It will be interesting to see how things go.

[40/70 Benchmark]

6 minutes ago, bluewave said:

The thing to watch is where the storm track sets up. While the models ave been correcting stronger with the ridge over the Bering Sea into the first week of December, they still have a robust MJO wave running through 4-6. So even if it’s not the dominant factor it can still influence the storm tracks. If it’s strong enough the lows could run close to or just inland from I-95. Then the cold we see on the week 2 means could come in behind any lows rather than in front of them .If the storm tracks are still too warm for the coast, then will know the MJO is still exerting some influence. Should the storm tracks slide east then we’ll know the block near Alaska won out. It will be interesting to see how things go.

Modern day 1980s....2018-2019 was like that.

[PhiEaglesfan712]

8 minutes ago, 40/70 Benchmark said:

Modern day 1980s....2018-2019 was like that.

In retrospect, 2018-19 wasn't that bad of a winter, considering the one that followed it. 18-19 was a nickels and dimes winter in the mid-Atlantic, but it was probably the one that provided the most consistent cold shots/snow of all the winters post-2015. Yes, 2017-18 and 2020-21 had more snow, but both of them either had an extended warm period (February for 17-18) or snow shutoff (late December-end of January 20-21). 18-19 is still the coldest Nov-Mar period in PHL post-2015. 1/31/2019 was the last time I really had to layer up.

If you want to see an all-around disaster winter, there's 2019-20.

[40/70 Benchmark]

43 minutes ago, PhiEaglesfan712 said:

In retrospect, 2018-19 wasn't that bad of a winter, considering the one that followed it. 18-19 was a nickels and dimes winter in the mid-Atlantic, but it was probably the one that provided the most consistent cold shots/snow of all the winters post-2015. Yes, 2017-18 and 2020-21 had more snow, but both of them either had an extended warm period (February for 17-18) or snow shutoff (late December-end of January 20-21). 18-19 is still the coldest Nov-Mar period in PHL post-2015. 1/31/2019 was the last time I really had to layer up.

If you want to see an all-around disaster winter, there's 2019-20.

If you want to convince me to take 2018 over 2021, I could probably buy it...but not even close on 2017 for me....hands down superior winter, I couldn't care less about February skewing the season warm.

I would also take 2019 over 2018 because I got the one big dog in December 2019. I would rather one big dog in a sea of warmth then a slew of 2-3" front enders with cold that rushes into freeze the puddles.

[PhiEaglesfan712]

Pretty funny how both 2017-18 and 2018-19 ended with the same DJF temperature for PHL. I'll take the highs of 2017-18 over the consistency of 2018-19.

But no way am I ever going to take 2019-20 over 2018-19. 19-20 is just another 11-12. I'm taking a winter with consistent cold shots and small snowstorms like 18-19 (and running) any day over a wall-to-wall torch, snowless winter like 11-12 or 19-20. At least we got some of the big October 2011 snowstorm. We were shut out in December 2019.

[40/70 Benchmark]

9 minutes ago, PhiEaglesfan712 said:

Pretty funny how both 2017-18 and 2018-19 ended with the same DJF temperature for PHL. I'll take the highs of 2017-18 over the consistency of 2018-19.

But no way am I ever going to take 2019-20 over 2018-19. 19-20 is just another 11-12. I'm taking a winter with consistent cold shots and small snowstorms like 18-19 (and running) any day over a wall-to-wall torch, snowless winter like 11-12 or 19-20. At least we got some of the big October 2011 snowstorm. We were shut out in December 2019.

They were comparable snow totals for me.

[michsnowfreak]

34 minutes ago, 40/70 Benchmark said:

They were comparable snow totals for me.

2018-19 and 2019-20 are actually good examples for when I mention how I worry more about pattern than temps. Certainly doesnt always or even usually work out like that, but it happens.

2018-19: DJF temp 28.9F, snowfall 31.3"

2019-20: DJF temp 32.6F, snowfall 43.7"

 

Other than last winter, 2018-19 was the only real dud snow season in this post-2015 mild era, yet the winter itself was barely warmer than avg, certainly an average-ish temp winter overall. But 2019-20, an average snow season, was the 11th warmest winter on record.

 

[FPizz]

41 minutes ago, 40/70 Benchmark said:

They were comparable snow totals for me.

Down this way 18-19 had 27", 19-20 had 7"

[michsnowfreak]

10 hours ago, BuffaloWeather said:

The pattern coming up looks incredible, so many wintry chances. The lakes are going to be firing the first week of December.

It really looks like a great pattern. Per OHWeather, it looks panhandle hook/cutter-ish initially the end of November and looks more clipper-ish by a week into December. 

First dusting of snow this morning, my sister told me my nephews were so excited. I never turn down a flake of snow, whether its January of April, but theres nothing like the excitement/anticipation at the beginning of the snow season/winter. And its even better when the weather cooperates during the holidays.

[michsnowfreak]

1 minute ago, FPizz said:

Down this way 18-19 had 27", 19-20 had 7"

2018-19 wasnt all bad, just a forgettable snow season here. We also had 3 ice storms and the insane arctic blast in late January. I still remember walking in the park in the bitter cold. The snow was so crunchy and the trees would not stop that eerie creak sound you only get when its SOO cold.

I think for most the clear winner in the post-2015 era is 2017-18. I also think many of us would kill to do a repeat of 2007-2015 or so.

[PhiEaglesfan712]

35 minutes ago, FPizz said:

Down this way 18-19 had 27", 19-20 had 7"

A little more south and a lot of locations had less than an inch of snow in 19-20.

PHL had 17.1" of snow in 18-19 and 0.3" in 19-20, while ACY had 17.8" in 18-19 and 0.5" in 19-20.

[GaWx]

 Natural gas is now up a whopping 7% for the day and is at its highest since way back in Oct of 2023. To those who don’t know, NG price trends reflect well on the trend in EPS and GEFS forecasted E US temperatures, especially for days 10-16. When there’s a day with a significant drop (eventually it has to happen), that would tell me without looking at the ensembles that the colder ensemble E US trend very well may have stopped.

[GaWx]

Note the change for 12/2-8 on the Euro Weeklies in just 4 days:

11/17 run:

 

11/21 run: 

[Stormchaserchuck1]

4 hours ago, GaWx said:

 Natural gas is now up a whopping 7% for the day and is at its highest since way back in Oct of 2023. To those who don’t know, NG price trends reflect well on the trend in EPS and GEFS forecasted E US temperatures, especially for days 10-16. When there’s a day with a significant drop (eventually it has to happen), that would tell me without looking at the ensembles that the colder ensemble E US trend very well may have stopped.

This is because of the constant -WPO being forecasted, through Day 16.  Beware though, 2022 started off like this.  2013 did have the pattern change from -PDO in Sept-Oct as a -WPO pattern. 

This is the +NAO/-EPO correlation I have been talking so much about, as is a default pattern right now. I was saying in the Summer that I would actually prefer +NAO in the Wintertime because of this correlation.