2025-2026 ENSO

[GaWx]

Here’s the latest GLAAM forecast: Ninoish

[Stormchaserchuck1]

SOI data is reliable and goes back to the 1800s. Here's the top 9 positive SOI Fall/Winters minus negative SOI Fall Winters 1900-1950.. fits our post-1950 composite. In other words, this image below is the typical La Nina state 1900-1950. 

 

March included

Here's precip

[Stormchaserchuck1]

1 hour ago, GaWx said:

Here’s the latest GLAAM forecast: Ninoish

Wonder if we'll finally break this strong +AO pattern, that has been there since May..

[michsnowfreak]

6 hours ago, yoda said:

Hope this hasn't been posted yet, if so my mistake... saw this new study this morning.  Looks interesting and will be reading... but I appreciate any thoughts by our experts here

https://www.google.com/amp/s/phys.org/news/2025-07-polar-vortex-patterns-shifting-winter.amp

https://www.science.org/doi/10.1126/sciadv.adq9557

 

Interesting read, and this has actually been mentioned by @Stormchaserchuck1 and myself before. For instance, this line: "As winters in the United States continue to warm on average, extreme cold snaps still manage to grip large swaths of the country with surprising ferocity."

In discussing some of the arctic outbreaks of recent years, the usual posters are very quick to try and put out the discussion  before it gets started, citing the mean winter temp in the U.S. and/or the cold/warm ranking of the mean temp of winter for the entire U.S., as if that takes away the arctic outbreaks. 

Some years have seen outbreaks in areas that are far more severe than at any time during past winters with an overall colder mean temp in that same area.

[donsutherland1]

59 minutes ago, michsnowfreak said:

Interesting read, and this has actually been mentioned by @Stormchaserchuck1 and myself before. For instance, this line: "As winters in the United States continue to warm on average, extreme cold snaps still manage to grip large swaths of the country with surprising ferocity."

In discussing some of the arctic outbreaks of recent years, the usual posters are very quick to try and put out the discussion  before it gets started, citing the mean winter temp in the U.S. and/or the cold/warm ranking of the mean temp of winter for the entire U.S., as if that takes away the arctic outbreaks. 

Some years have seen outbreaks in areas that are far more severe than at any time during past winters with an overall colder mean temp in that same area.

Good studies. I suspect that the warming of the West Pacific is having an impact on the polar vortex. Arctic outbreaks remain possible and it is plausible that they can, at times, penetrate farther south than they had in the past.

However, because the deep cold pool is smaller than it was prior to 2000, in general, the cold shots tend not to be as expansive or as prolonged as they once were absent a "stuck pattern." That's why the overall coverage of cold anomalies is typically less than it was during earlier winters (e.g., February 1979 vs. February 2015) and the only nationwide winter among the top 30 coldest winters among the 2000s was 2009-10. 

[GaWx]

4 minutes ago, donsutherland1 said:

Good studies. I suspect that the warming of the West Pacific is having an impact on the polar vortex. Arctic outbreaks remain possible and it is plausible that they can, at times, penetrate farther south than they had in the past. However, because the deep cold pool is smaller than it was prior to 2000, in general, the cold shots tend not to be as expansive or as prolonged as they once were absent a "stuck pattern." That's why the overall coverage of cold anomalies is typically less than it was during earlier winters (think February 1979 vs. February 2015). 

Thanks Don.

 But as 30 year “normals” also rise, shouldn’t the cold anomaly coverage in cold shots at least in theory be as expansive as before?

[donsutherland1]

4 hours ago, GaWx said:

Thanks Don.

 But as 30 year “normals” also rise, shouldn’t the cold anomaly coverage in cold shots at least in theory be as expansive as before?

In theory, yes. But the Arctic is warming faster than the mid-latitudes and the deep cold pool is shrinking. That’s reducing the coverage of cold anomalies even against a warmer baseline.

[40/70 Benchmark]

I know someone posted the JJ MEI value, but any idea why it has't updated here?

https://psl.noaa.gov/enso/mei/

[bluewave]

15 hours ago, donsutherland1 said:

Good studies. I suspect that the warming of the West Pacific is having an impact on the polar vortex. Arctic outbreaks remain possible and it is plausible that they can, at times, penetrate farther south than they had in the past.

However, because the deep cold pool is smaller than it was prior to 2000, in general, the cold shots tend not to be as expansive or as prolonged as they once were absent a "stuck pattern." That's why the overall coverage of cold anomalies is typically less than it was during earlier winters (e.g., February 1979 vs. February 2015) and the only nationwide winter among the top 30 coldest winters among the 2000s was 2009-10. 

Yeah, the aerial coverage of the 850mb cold pool was among the smallest on record last winter. This is why that even though some of the coldest departures in the Northern Hemisphere were found in the CONUS, 2024-2025 was the 27th warmest winter at 34.07°. When we had much more expansive 850mb cold pools in the Northern Hemisphere back in the late 1970s, we had our coldest winter in 1978-1979 at 26.62°. The general observation has been the areas of the 500mb ridges have been expanding leaving smaller cold troughs.

The late January 2025 Arctic outbreak in Baton Rouge LA and record snow was a great example of this recent phenomenon. Although they tied their all-time January low of 7°, the Arctic outbreak only lasted 3 days. They had a record high of 81° in early January and 83° in early February. So one of the more locally focused and limited Arctic outbreaks experienced in the CONUS. Overall January finished up at only the 25th coldest with a modest -3 cold departure against the warmest climate normals. Past occurrences of record snow and cold that far south was accompanied at times by historic cold and snow all the way to the East Coast which didn’t happen this time.

[PhiEaglesfan712]

Come to think of it, we really haven't really had an arctic outbreak in the mid-Atlantic/Northeast in the 2020s decade. The last one that could qualify as one was the one in late January 2019, but that was for about a few days. Before that, late December 2017/early January 2018. But the last real sustained arctic outbreak was 2015, which lasted for the greater part of 3 months (January-March). I still can't believe the Aetna lake in Medford, NJ was frozen in late February/early March.

[FPizz]

39 minutes ago, PhiEaglesfan712 said:

Come to think of it, we really haven't really had an arctic outbreak in the mid-Atlantic/Northeast in the 2020s decade. The last one that could qualify as one was the one in late January 2019, but that was for about a few days. Before that, late December 2017/early January 2018. But the last real sustained arctic outbreak was 2015, which lasted for the greater part of 3 months (January-March). I still can't believe the Aetna lake in Medford, NJ was frozen in late February/early March.

Last year I got below zero 5x, the most I could remember, and Boonton reservoir was frozen for at least 6 weeks and is 3x larger than Aetna Lake.  

[bluewave]

1 hour ago, PhiEaglesfan712 said:

Come to think of it, we really haven't really had an arctic outbreak in the mid-Atlantic/Northeast in the 2020s decade. The last one that could qualify as one was the one in late January 2019, but that was for about a few days. Before that, late December 2017/early January 2018. But the last real sustained arctic outbreak was 2015, which lasted for the greater part of 3 months (January-March). I still can't believe the Aetna lake in Medford, NJ was frozen in late February/early March.

Steady decrease in lows under 10° across the Northeast with many locations recording some of there lowest winter numbers during the 2020s.

 

[GaWx]

3 hours ago, bluewave said:

Yeah, the aerial coverage of the 850mb cold pool was among the smallest on record last winter. This is why that even though some of the coldest departures in the Northern Hemisphere were found in the CONUS, 2024-2025 was the 27th warmest winter at 34.07°. When we had much more expansive 850mb cold pools in the Northern Hemisphere back in the late 1970s, we had our coldest winter in 1978-1979 at 26.62°. The general observation has been the areas of the 500mb ridges have been expanding leaving smaller cold troughs.

The late January 2025 Arctic outbreak in Baton Rouge LA and record snow was a great example of this recent phenomenon. Although they tied their all-time January low of 7°, the Arctic outbreak only lasted 3 days. They had a record high of 81° in early January and 83° in early February. So one of the more locally focused and limited Arctic outbreaks experienced in the CONUS. Overall January finished up at only the 25th coldest with a modest -3 cold departure against the warmest climate normals. Past occurrences of record snow and cold that far south was accompanied at times by historic cold and snow all the way to the East Coast which didn’t happen this time.

 My location in SAV, GA, had ~3” of sleet/snow/ZR Jan 21-22, 2025. Easily >2” of it was sleet at my location. That’s way more sleet than any other winter storm on record! Official records go back >150 years. The official record heaviest sleet was <1”. The liquid equivalent/melted precip at my location was ~1.15”! The last time that much liquid equiv of wintry precip fell in this area from one storm was way back with the icestorm of Jan 25-6, 1922, with its 1.36”. Due to most of the precip falling as sleet and the followup cold, it took a whopping 5 days to completely melt!

 The prior SAV frozen precip of any amount (including trace amounts) was the Jan 3, 2018 storm. This storm, similar to Jan 21-22, 2025, also had purely wintry precip (mix of ZR, sleet, and snow) with ~0.75” of liquid equiv at my location. At the time, it was also the largest amount of LE as well as heaviest ZR from one storm here since the Jan 25-6 storm of 1922! It took 4 days to melt due to most of the precip falling with temps in the mid to upper 20s and followup cold. The week Jan 1-7, 2018, was the coldest 7 day period in a number of decades!

 The 7 years of not even a T of wintry precip between the big 2018 and 2025 winter storms was the longest interval of no wintry precip in the SAV area at least back to the 1880s!

 

 

[bluewave]

30 minutes ago, GaWx said:

 My location in SAV, GA, had ~3” of sleet/snow/ZR Jan 21-22, 2025. Easily >2” of it was sleet at my location. That’s way more sleet than any other winter storm on record! Official records go back >150 years. The official record heaviest sleet was <1”. The liquid equivalent/melted precip at my location was ~1.15”! The last time that much liquid equiv of wintry precip fell in this area from one storm was way back with the icestorm of Jan 25-6, 1922, with its 1.36”. Due to most of the precip falling as sleet and the followup cold, it took a whopping 5 days to completely melt!

 The prior SAV frozen precip of any amount (including trace amounts) was the Jan 3, 2018 storm. This storm, similar to Jan 21-22, 2025, also had purely wintry precip (mix of ZR, sleet, and snow) with ~0.75” of liquid equiv at my location. At the time, it was also the largest amount of LE as well as heaviest ZR from one storm here since the Jan 25-6 storm of 1922! It took 4 days to melt due to most of the precip falling with temps in the mid to upper 20s and followup cold. The week Jan 1-7, 2018, was the coldest 7 day period in a number of decades!

 The 7 years of not even a T of wintry precip between the big 2018 and 2025 winter storms was the longest interval of no wintry precip in the SAV area at least back to the 1880s!

 

 

I am glad that you were one of the few parts of the country to get some record frozen precipitation last winter like the Gulf Coast. But it was narrowly focused over the Southeast. The January cold in your area didn’t have any lasting power as there were multiple record 80°+ highs shortly after. 

[FPizz]

1 hour ago, GaWx said:

 My location in SAV, GA, had ~3” of sleet/snow/ZR Jan 21-22, 2025. Easily >2” of it was sleet at my location. That’s way more sleet than any other winter storm on record! Official records go back >150 years. The official record heaviest sleet was <1”. The liquid equivalent/melted precip at my location was ~1.15”! The last time that much liquid equiv of wintry precip fell in this area from one storm was way back with the icestorm of Jan 25-6, 1922, with its 1.36”. Due to most of the precip falling as sleet and the followup cold, it took a whopping 5 days to completely melt!

 The prior SAV frozen precip of any amount (including trace amounts) was the Jan 3, 2018 storm. This storm, similar to Jan 21-22, 2025, also had purely wintry precip (mix of ZR, sleet, and snow) with ~0.75” of liquid equiv at my location. At the time, it was also the largest amount of LE as well as heaviest ZR from one storm here since the Jan 25-6 storm of 1922! It took 4 days to melt due to most of the precip falling with temps in the mid to upper 20s and followup cold. The week Jan 1-7, 2018, was the coldest 7 day period in a number of decades!

 The 7 years of not even a T of wintry precip between the big 2018 and 2025 winter storms was the longest interval of no wintry precip in the SAV area at least back to the 1880s!

 

 

Impressive.  Even record frozen precip up here often melts off in a few days.  Some here act like we used to live in the Arctic up until 2016.