2025-2026 ENSO

[jconsor]

Top 10 cold period past two and a half weeks for eastern US:

https://x.com/wxjerdman/status/2019729810914992195

[michsnowfreak]

24 minutes ago, jconsor said:

Top 10 cold period past two and a half weeks for eastern US:

https://x.com/wxjerdman/status/2019729810914992195

Wow thanks for posting this. I knew it was cold but didn't realize the impressive nature of it.

@bluewave frequently mentions that cold anamolies are short in duration. This is the opposite. January 15 - February 4 is the coldest 3 weeks of the year on avg to begin with. 2026 now ranks 3rd coldest for that 3 week stretch at Detroit in 153 years of record. Only 1918 & 1963 were colder.

Pittsburgh also ranks 3rd in 152 years of record. Cleveland 4th in 156 years. Toledo 6th in 153 years. And even NYC 17th in 158 years.

 @FPizz @mitchnick @MJO812

[EastonSN+]

2 hours ago, snowman19 said:

 

Great - another cold and rainy spring

[EastonSN+]

12 hours ago, GaWx said:

Anthony,

 It’s important to be aware that the WxBell Euro EW 2m maps have a notable 2m temp cold bias as I’ve posted about repeatedly. I have an easy way to show this by posting the in-house Euro weeklies maps covering the same period and comparing to this WB map.

Examples:

 -The Rockies and west coast are a very cold -3F to -10F for 2/21-3/22 on your map. What?!?
 
 -Chicago/OH Valley are -2F, Asheville is -3F, Detroit is -4F, DC/Richmond are -3F, ATL/CLT are -1F.

 -Now check out ECMWF’s in-house maps for the truth: no BN on any maps covering the same period for the locations I listed

2/23-3/1:

 

3/2-8:

 

3/9-15:

 

3/16-22:

 So based on the truth, the Rockies and much of the West should be a bit AN instead of well BN. So, that means they’re mainly 5F to 10F too cold on WB!

 The E cities I listed should be NN in Chic, Det, Ohio Valley, DC, Richmond, and +1F in ATL/CLT/ASH. So, that means these locations are 2-4F too cold on WB.

 WxBell has NYC at -4F. The truth is that they should be -1F. So, NYC is 3F too cold on WB.

@donsutherland1this remains a problem

Just for the northern MA and Northeast, thats a decent look for BN temps, albeit slightly.

[EastonSN+]

6 hours ago, so_whats_happening said:

Unfortunately those 10 or so days were not all that fun for here. Eastern NC though I'm sure was just in love with this pattern lol.

From the looks of the Nina phase 1 passage is taking place this weekend. Large cold dump with warming through much of the plains showing up. Going forward it does show cold building back up into Canada to be unleashed again at some point maybe the last week or so of February into early March as we move into Phase 2/3?

Hopefully phase 3 occurrs by 1st week of March (considering lag).

[Violentweatherfan]

6 hours ago, nycwinter said:

dt says next couple of weeks going to be bad if you want snow in the east

 

He also pointed out how off the forecast was for the MJO. It’s definitely going in the wrong direction so here is to hoping if is off about that.

[George001]

22 hours ago, MJO812 said:

February doesnt look warm at all for the east. Same thing has been happening all winter. Looks warm in the east in the long range only to correct colder.

I agree it will end up being a cold and possibly snowy month overall, but I do agree with the idea of a mid month relaxation period.

[TheClimateChanger]

3 hours ago, donsutherland1 said:

Yes. That's correct. The ECMWF is actually using a potentially somewhat warmer period than 1991-2020 for calculating its subseasonal anomalies. The site mentions:

The mean anomalies are derived from the ECMWF Sub-seasonal range ensemble consisting of 100 ensemble members plus a control member and averaged over a seven day period. Anomalies are calculated with respect to the Model Climate, which is derived from re-running an 11-member ensemble over the last 20 years, giving 220 realisations in total.

See bottom of: https://charts.ecmwf.int/products/opencharts_extended_meteogram?base_time=202602050000&lat=51.4333&lon=-1.0&station_name=Reading

A fuller discussion, which also notes 20 years of values, is here: https://confluence.ecmwf.int/display/FUG/Section+5.3.2+SUBS-M-climate%2C+the+sub-seasonal+model+climatehttps://confluence.ecmwf.int/display/FUG/Section+5.3.2+SUBS-M-climate%2C+the+sub-seasonal+model+climate

Below is a quick comparison of the 1991-2020 period with the last 20 years for 10 select cities to provide an idea of how things have changed.

 

Wow, that's quite impressive IMO, considering 1991-2020 was, by far, the warmest climatological normal period in recorded history. And the last 20 years are outpacing them by 0.6-1F across the board. One would think the warmer norms would tilt the scale towards more cooler than normal years, but, in fact, one finds the opposite phenomenon. Very intriguing. 

[GaWx]

2 hours ago, jconsor said:

Top 10 cold period past two and a half weeks for eastern US:

https://x.com/wxjerdman/status/2019729810914992195

Dominant indices Jan 15-Feb 4:
- moderate to strong +PNA
- strong to very strong -AO
- moderate to very strong -EPO
- moderate to strong -WPO
- so one of the greatest 3 week long combos of +PNA, -AO, -EPO, -WPO on record
- strong to moderate MJO phases 6-7 and weak phase 8
- neutral NAO averaged out with no strong anomalies 

[donsutherland1]

Uncertainty about the February 15-28 period has increased. What is fairly certain are the following:

1) Substantial warmup in the Plains States
2) Brief cool shot to the Southwest and then a return of warmer conditions. The cool shot likely won't be sufficient to preclude Phoenix from experiencing its warmest winter on record.

Moderation is likely to occur across the Great Lakes Region, Northeast, Mid-Atlantic, and Southeast during and after February 10th. What happens beyond 7-10 days is where things become increasingly uncertain. The CFSv2 favors a continuation of above normal temperatures through the end of February. The ECMWF weeklies bring colder conditions for the February 23-28 period.

CFSv2:

ECMWF Weeklies:

Even as wave lengths are shortening, the Arctic Oscillation (AO) could hold the key. The EPS and GEFS agree on the development of a WPO-, EPO+, PNA- pattern. During such patterns, conditions in the East tend to be much colder when the AO is negative than when it is positive. 

New York City provides a good example. Since 1980, WPO-, EPO+, PNA-, AO- patterns have seen a mean February 15-28 temperature of 33.9°. In contrast, WPO-, EPO+, PNA-, AO+ patterns have seen a mean temperature of 44.5°. So, if the AO goes positive, the warmth from the Plains will likely come eastward.

WPO-, EPO+, PNA-, AO- Patterns:

WPO-, EPO+, PNA-, AO+ Patterns:

The latest AO forecast is below. 

A near neutral AO would favor near seasonable to somewhat above seasonable temperatures in the East. Historic experience following the breakdown of long-duration (25-day or longer) AO- regimes that began in February favors AO variability following the breakdown of such regimes. Only 1986 saw a prolonged and strong AO+ regime develop.

As noted previously, due to shortening wave lengths, the consensus outcome of a resumption of above normal temperatures in the Southwest to close out February is the base case.

[TheClimateChanger]

1 hour ago, donsutherland1 said:

Uncertainty about the February 15-28 period has increased. What is fairly certain are the following:

1) Substantial warmup in the Plains States
2) Brief cool shot to the Southwest and then a return of warmer conditions. The cool shot likely won't be sufficient to preclude Phoenix from experiencing its warmest winter on record.

Moderation is likely to occur across the Great Lakes Region, Northeast, Mid-Atlantic, and Southeast during and after February 10th. What happens beyond 7-10 days is where things become increasingly uncertain. The CFSv2 favors a continuation of above normal temperatures through the end of February. The ECMWF weeklies bring colder conditions for the February 23-28 period.

CFSv2:

ECMWF Weeklies:

Even as wave lengths are shortening, the Arctic Oscillation (AO) could hold the key. The EPS and GEFS agree on the development of a WPO-, EPO+, PNA- pattern. During such patterns, conditions in the East tend to be much colder when the AO is negative than when it is positive. 

New York City provides a good example. Since 1980, WPO-, EPO+, PNA-, AO- patterns have seen a mean February 15-28 temperature of 33.9°. In contrast, WPO-, EPO+, PNA-, AO+ patterns have seen a mean temperature of 44.5°. So, if the AO goes positive, the warmth from the Plains will likely come eastward.

WPO-, EPO+, PNA-, AO- Patterns:

WPO-, EPO+, PNA-, AO+ Patterns:

The latest AO forecast is below. 

A near neutral AO would favor near seasonable to somewhat above seasonable temperatures in the East. Historic experience following the breakdown of long-duration (25-day or longer) AO- regimes that began in February favors AO variability following the breakdown of such regimes. Only 1986 saw a prolonged and strong AO+ regime develop.

As noted previously, due to shortening wave lengths, the consensus outcome of a resumption of above normal temperatures in the Southwest to close out February is the base case.

Thanks for the update, Don.  Wild start to February. Almost exactly "normal" through the first 4 days, but actually 20F warmer than normal in the northern Rockies and 20F colder than normal in parts of the Eastern U.S. Very spring-like 73F in Rapid City, SD yesterday (2F shy of February monthly record high), while the deep freeze continues in the Ohio Valley and Great Lakes.

[NyWxGuy]

If we hold onto that -NAO, we should be in decent shape. If the NAO turns +NAO, the warmth that has plagued the west and plains since December will have to come east. 

[roardog]

6 hours ago, michsnowfreak said:

Wow thanks for posting this. I knew it was cold but didn't realize the impressive nature of it.

@bluewave frequently mentions that cold anamolies are short in duration. This is the opposite. January 15 - February 4 is the coldest 3 weeks of the year on avg to begin with. 2026 now ranks 3rd coldest for that 3 week stretch at Detroit in 153 years of record. Only 1918 & 1963 were colder.

Pittsburgh also ranks 3rd in 152 years of record. Cleveland 4th in 156 years. Toledo 6th in 153 years. And even NYC 17th in 158 years.

 @FPizz @mitchnick @MJO812

Some were saying the cold wasn’t impressive but that looks impressive to me. It might not match the warm anomalies out west with a warmer world but to downplay the cold the last three weeks isn’t being honest. 

[PositiveEPOEnjoyer]

On 2/5/2026 at 9:47 AM, MJO812 said:

February doesnt look warm at all for the east. Same thing has been happening all winter. Looks warm in the east in the long range only to correct colder.

This doesn’t look too promising for cold temps to stick around in the east.

[snowman19]

This doesn’t look too promising for cold temps to stick around in the east.

Don’t even bother. Not worth it. He’s going to say that the experts with Master’s and Ph.D. Degrees in Meteorology and Climatology over at the CPC are dead wrong and don’t know what they’re talking about…..

[NyWxGuy]

1 hour ago, PositiveEPOEnjoyer said:

This doesn’t look too promising for cold temps to stick around in the east.

That’s the ridging we’ve been seeing centered over the plains since December. But we’ve also had a -NAO since then to keep us colder than normal. If we lose the -NAO, we’ll get warm pretty fast. West coast troughing only works when you have cross polar flow. Otherwise with a ridge in the east, those western troughs will just cut 

[PositiveEPOEnjoyer]

3 hours ago, NyWxGuy said:

That’s the ridging we’ve been seeing centered over the plains since December. But we’ve also had a -NAO since then to keep us colder than normal. If we lose the -NAO, we’ll get warm pretty fast. West coast troughing only works when you have cross polar flow. Otherwise with a ridge in the east, those western troughs will just cut 

-NAO tends to be a stronger cold signal for the west in Feb. Of course it can still have implications in the east, but it wouldn't be as notable.

[PositiveEPOEnjoyer]

7 hours ago, roardog said:

Some were saying the cold wasn’t impressive but that looks impressive to me. It might not match the warm anomalies out west with a warmer world but to downplay the cold the last three weeks isn’t being honest. 

who's downplaying the cold? It was a notable two week stretch of cold, but there have been plenty of similarly cold (or colder) stretches in the CONUS over the years (not just past, recent as well). It's not just the anomalies, but also the duration of the warmth out west which has been more impressive than any cold in the east this season.

[LakePaste25]

1 hour ago, PositiveEPOEnjoyer said:

-NAO tends to be a stronger cold signal for the west in Feb. Of course it can still have implications in the east, but it wouldn't be as notable.

What?? 

 

[NyWxGuy]

1 hour ago, PositiveEPOEnjoyer said:

who's downplaying the cold? It was a notable two week stretch of cold, but there have been plenty of similarly cold (or colder) stretches in the CONUS over the years (not just past, recent as well). It's not just the anomalies, but also the duration of the warmth out west which has been more impressive than any cold in the east this season.

Absolutely. The warmth in the west has been astonishing and smashing records left and right. The cold in the east has been impressive; but not nearly in the same category as the winter that never even began in the west 

[roardog]

3 hours ago, PositiveEPOEnjoyer said:

there have been plenty of similarly cold (or colder) stretches in the CONUS over the years (not just past, recent as well). 

Yeah. Third coldest in 152 years happens all the time. Yes, you’re downplaying it. lol

[bluewave]

On 2/6/2026 at 7:16 AM, michsnowfreak said:

Wow thanks for posting this. I knew it was cold but didn't realize the impressive nature of it.

@bluewave frequently mentions that cold anamolies are short in duration. This is the opposite. January 15 - February 4 is the coldest 3 weeks of the year on avg to begin with. 2026 now ranks 3rd coldest for that 3 week stretch at Detroit in 153 years of record. Only 1918 & 1963 were colder.

Pittsburgh also ranks 3rd in 152 years of record. Cleveland 4th in 156 years. Toledo 6th in 153 years. And even NYC 17th in 158 years.

 @FPizz @mitchnick @MJO812

On 2/6/2026 at 7:16 AM, michsnowfreak said:

 

 @FPizz @mitchnick @MJO812

Getting a top 10 coldest for a week to a month across a region or adjacent regions is impressive cold but is considered a shorter duration and smaller geographic footprint. 

My discussions have been focused on seasonal top 10 cold which spans the 3 winter months of December to February. This hasn’t happened on a national level since the 1970s.

These shorter duration Arctic outbreaks ranking in the top 10 and over a smaller geographic region than the past have been a common feature of our climate in recent years.

Think back to the regional cold records during February 2021. In the old days these regional monthly top 10s would extend to seasonal which hasn’t happened in recent years. Plus the magnitude of the warmth across the Plains in December 2021 was greater than the cold in February 2021. 

None of the cold records so far in the East rank as cold as the warm records in the West have for geographic extent, magnitude, or duration. Since the Northern Hemisphere cold pool is so much smaller than it used to be.This winter has been among the warmest on record for the Northern Hemisphere. 
 

 

 

[mitchnick]

2 hours ago, bluewave said:

Getting a top 10 coldest for a week to a month across a region or adjacent regions is impressive cold but is considered a shorter duration and smaller geographic footprint. 

My discussions have been focused on seasonal top 10 cold which spans the 3 winter months of December to February. This hasn’t happened on a national level since the 1970s.

These shorter duration Arctic outbreaks ranking in the top 10 and over a smaller geographic region than the past have been a common feature of our climate in recent years.

Think back to the regional cold records during February 2021. In the old days these regional monthly top 10s would extend to seasonal which hasn’t happened in recent years. Plus the magnitude of the warmth across the Plains in December 2021 was greater than the cold in February 2021. 

None of the cold records so far in the East rank as cold as the warm records in the West have for geographic extent, magnitude, or duration. Since the Northern Hemisphere cold pool is so much smaller than it used to be.This winter has been among the warmest on record for the Northern Hemisphere. 
 

 

 

So??? Winter's not over.

[NyWxGuy]

2 hours ago, bluewave said:

Getting a top 10 coldest for a week to a month across a region or adjacent regions is impressive cold but is considered a shorter duration and smaller geographic footprint. 

My discussions have been focused on seasonal top 10 cold which spans the 3 winter months of December to February. This hasn’t happened on a national level since the 1970s.

These shorter duration Arctic outbreaks ranking in the top 10 and over a smaller geographic region than the past have been a common feature of our climate in recent years.

Think back to the regional cold records during February 2021. In the old days these regional monthly top 10s would extend to seasonal which hasn’t happened in recent years. Plus the magnitude of the warmth across the Plains in December 2021 was greater than the cold in February 2021. 

None of the cold records so far in the East rank as cold as the warm records in the West have for geographic extent, magnitude, or duration. Since the Northern Hemisphere cold pool is so much smaller than it used to be.This winter has been among the warmest on record for the Northern Hemisphere. 
 

 

 

The cold temperature anomalies are impressive for the Eastern US, but when you take a holistic look at the United States as a whole, the cold temperature anomalies are much less impressive. Especially when you have a snowless Rocky Mountains and spring like weather up into southern Canada. That’s the real story here.

[EastonSN+]

Phases 4 through 7 are warm in Feb. Need to get this back to 8 quick considering the lag. Moves from phase 2 to 4 in three days.

[EastonSN+]

@donsutherland1 you mentioned the importance of a negative AO. Looks like it may be dropping towards the end....

[EastonSN+]

I will be honest I do not understand the exact effects from this other than we want it to drop to get blocking. While not dropping below zero (reversal), it does drop below the Middle red line. Does this aid in blocking?

[Terpeast]

1 hour ago, EastonSN+ said:

I will be honest I do not understand the exact effects from this other than we want it to drop to get blocking. While not dropping below zero (reversal), it does drop below the Middle red line. Does this aid in blocking?

Yes, a weaker pv supports blocking. It doesn’t have to reverse for blocking to suddenly appear.