2026-2027 Super El Nino

[bluewave]

2 hours ago, GaWx said:

Thanks, Chris.

 1. The April run comes in a bit stronger for ONI than the Mar run for the same months compared. For example, the Mar run had Sep at ~+2.1 vs the Apr run having Sep at ~+2.25. So, that’s clearly a bullish trend since the prior run for a stronger ONI.

2. RONI is still ~0.5 cooler than ONI. So, ~0.5 still needs to be subtracted off of the Euro output to approximate its implied RONI prog.

3. It’s important to still keep in mind a longterm warm bias of the Euro ONI progs based on the avg of ~20 years of progs though those that verify as El Niño have averaged a lower warm bias.

 Examples:

-the April ‘17 run progged moderate El Niño (+1.1) for ASO (see below) vs it verifying way down at -0.3 for ONI, a whopping +1.4 miss. That’s an extreme, of course, but one doesn’t find misses anywhere near that same magnitude the other way. In addition, the April ‘14 run had ASO up at +1.5 vs verification of only +0.3, another big miss of +1.2. Furthermore, the April ‘12 run had ASO up at +1.0 vs verification of only +0.4 for a +0.6 miss.

 Some recent April run ASO ONI misses have also been large to the too warm side:

-2025: ASO prog of +0.4 vs actual of -0.4 for miss of +0.8

 

-2022: ASO prog of -0.3 vs actual of -1.0 for miss of +0.7

 

-2021: ASO prog of 0 vs actual of -0.6 for a miss of +0.6

 

2020: ASO prog of -0.1 vs actual of -0.9 for a miss of +0.8

 

 So, based on the -0.5 RONI adj. and the notable Euro warm bias, the actual RONI peak could easily verify as only a moderate peak. My current wild guess is for low to middle end strong RONI peak.

Back in 2023-2024 there was a pretty big spread between ONI and RONI. The ONI peaked at +2.1 C and the RONI at +1.5 C .Yet the 500 mb pattern across the Northern Tier and Canada was similar to 1997-1998 with the CONUS setting the warmest winter on record.

Perhaps the weaker RONI was related to the lack of a robust Nino trough across Mid-Atlantic and Southeast and weaker Aleutian Low.

Plus we got a big global temperature super El Niño baseline jump even higher than 1997-1998 and 2015-2016. Also note the global temperatures hardly fell in 2025.

[Stormchaserchuck1]

Most extreme March NAO on record, +2.69. The composite is actually a cooler May, when rolled forward.

Just interesting - look at all this equilateral warmth later in the year, correlating with March +NAO

[40/70 Benchmark]

7 hours ago, bluewave said:

Back in 2023-2024 there was a pretty big spread between ONI and RONI. The ONI peaked at +2.1 C and the RONI at +1.5 C .Yet the 500 mb pattern across the Northern Tier and Canada was similar to 1997-1998 with the CONUS setting the warmest winter on record.

Perhaps the weaker RONI was related to the lack of a robust Nino trough across Mid-Atlantic and Southeast and weaker Aleutian Low.

Plus we got a big global temperature super El Niño baseline jump even higher than 1997-1998 and 2015-2016. Also note the global temperatures hardly fell in 2025.

That's my concern 2023...but then again, I'm not sure winter enthusiasts would feel any better if the RONI and ONI were in lock-step.

[Stormchaserchuck1]

1 hour ago, bluewave said:

Back in 2023-2024 there was a pretty big spread between ONI and RONI. The ONI peaked at +2.1 C and the RONI at +1.5 C .Yet the 500 mb pattern across the Northern Tier and Canada was similar to 1997-1998 with the CONUS setting the warmest winter on record.

Perhaps the weaker RONI was related to the lack of a robust Nino trough across Mid-Atlantic and Southeast and weaker Aleutian Low.

N. Pacific is ENSO's greatest correlation

East-based shifts the Canadian ridge more east

[snowman19]

Wow….

[roardog]

This is really going to be fascinating to watch. If we didn’t have that very strong Nino in 23-24, I think I would be fully on board for a super Nino this year. If we would have had a strong Nina in the last two years I might even be reluctantly on board. However, since we never get such a strong Nino so close in years, it just makes me feel like something is going to fail that the models can’t see right now. In 2022 we even had the MEI get down to something like -2.2 which made a rebound strong Nino seem likely. We have nothing like that this year. 

[brooklynwx99]

gotta pass the spring barrier. this is like a 10 day EPS forecast but for ENSO at this point in the year

[GaWx]

39 minutes ago, snowman19 said:

Wow….
 

To get the strongest Nino in 140 years, the ONI would probably need to get up to ~3.0 to allow RONI to exceed the 2.5 RONI peak of 1982-3 and thus become the strongest since 1887-8. Keep in mind the Euro longterm warm bias that could possibly be causing its April prog to be too warm.

[Stormchaserchuck1]

49 minutes ago, roardog said:

This is really going to be fascinating to watch. If we didn’t have that very strong Nino in 23-24, I think I would be fully on board for a super Nino this year. If we would have had a strong Nina in the last two years I might even be reluctantly on board. However, since we never get such a strong Nino so close in years, it just makes me feel like something is going to fail that the models can’t see right now. In 2022 we even had the MEI get down to something like -2.2 which made a rebound strong Nino seem likely. We have nothing like that this year. 

5 of the last 6 years have been Nina. The average RONI for last 6 years is -0.73c/yr

[roardog]

21 minutes ago, Stormchaserchuck1 said:

5 of the last 6 years have been Nina. The average RONI for last 6 years is -0.73c/yr

How much do the Nina years prior to 23-24 matter though? Wouldn’t that very strong Nino essentially “reset” that?

[SnowGoose69]

1 hour ago, roardog said:

This is really going to be fascinating to watch. If we didn’t have that very strong Nino in 23-24, I think I would be fully on board for a super Nino this year. If we would have had a strong Nina in the last two years I might even be reluctantly on board. However, since we never get such a strong Nino so close in years, it just makes me feel like something is going to fail that the models can’t see right now. In 2022 we even had the MEI get down to something like -2.2 which made a rebound strong Nino seem likely. We have nothing like that this year. 

This one would at least probably act like an E Nino.  23-24 really did not, at least not in the SE US and MA

[brooklynwx99]

for the record, this should be a strong Nino per ONI and even RONI, but taking those +2.5C euro forecasts in early April to heart is silly. wait a couple of months and see if it sticks. the euro has overdone many a Nino in the past

[Stormchaserchuck1]

3 hours ago, roardog said:

How much do the Nina years prior to 23-24 matter though? Wouldn’t that very strong Nino essentially “reset” that?

Last two years were -1.1 and -1.0 RONI, so average of last 3 years is -0.2c/yr.

I've found that 4/6+ same ENSO state shows strong tendency to reverse in the following +1-3 years. Likewise, +3-5 years after a Strong Nino (23-24) has El Nino tendency, so we are kind of hitting this from both angles. 

[George001]

4 hours ago, brooklynwx99 said:

gotta pass the spring barrier. this is like a 10 day EPS forecast but for ENSO at this point in the year

Yep. A super Nino is possible but we don’t know what is going to happen. A moderate or strong event is possible as well. 

[40/70 Benchmark]

7 hours ago, bluewave said:

Back in 2023-2024 there was a pretty big spread between ONI and RONI. The ONI peaked at +2.1 C and the RONI at +1.5 C .Yet the 500 mb pattern across the Northern Tier and Canada was similar to 1997-1998 with the CONUS setting the warmest winter on record.

Perhaps the weaker RONI was related to the lack of a robust Nino trough across Mid-Atlantic and Southeast and weaker Aleutian Low.

Plus we got a big global temperature super El Niño baseline jump even higher than 1997-1998 and 2015-2016. Also note the global temperatures hardly fell in 2025.

 

6 hours ago, 40/70 Benchmark said:

That's my concern 2023...but then again, I'm not sure winter enthusiasts would feel any better if the RONI and ONI were in lock-step.

 

6 hours ago, Stormchaserchuck1 said:

N. Pacific is ENSO's greatest correlation

East-based shifts the Canadian ridge more east

@Stormchaserchuck1, I agree that the correlation tools have some utility, but I do think that @bluewave is onto something with the lower RONI being reflective of a negative impact for eastern winter enthusiasts....ie cool ENSO residue. Consider several moderate to strong El Nino events that were "good".....ie 1957, 1965, 1986, 2002, and 2009...EVERY ONE OF THEM had a RONI was at least equal to, or GREATER than the ONI.

[Stormchaserchuck1]

The RONI isn't an index like the NAO or Solar cycle. It's relative ENSO index, to account for global warming. To compare differences in pattern in RONI vs ONI is just to talk about global warming trend of late. There's not a magical formula in RONI that makes it stronger than ONI a good pattern. You are basically just saying before 2010 was easier to get a cooler 500mb pattern. I'm pointing out that the area where ENSO has most impact - the N. Pacific - has correlated better to the RONI than ONI as of late, making RONI a better gauge to ENSO's impact. 

[40/70 Benchmark]

11 minutes ago, Stormchaserchuck1 said:

The RONI isn't an index like the NAO or Solar cycle. It's relative ENSO index, to account for global warming. To compare differences in pattern in RONI vs ONI is just to talk about global warming trend of late. There's not a magical formula in RONI that makes it stronger than ONI a good pattern. You are basically just saying before 2010 was easier to get a cooler 500mb pattern. I'm pointing out that the area where ENSO has most impact - the N. Pacific - has correlated better to the RONI than ONI as of late, making RONI a better gauge as to ENSO's impact. 

You are misunderstanding me....I know what RONI is...it's not the reading itself that I am concerning myself with. It's what it represents....we WANT the El Niño to correlate to the North Pacific pattern, so having the RONI lag the ONI does not mean that it's a "weaker" El Niño...it means that there is another force, likely of cool ENSO ilk, competing with the El Nino, and it's not forcing the north Pac pattern to a degree commensurate with the ONI intensity. If it were simply a weaker El Niño....it's probably more west-based and the Aleutian low is thus further west, which is favorable....but a lower RONI may mimic a west-based in the SST pattern, but actually has so much warmth in the western Pacific as to introduce more MC forcing than is typical in a potent El Niño. 

We'll see what happens have a lower RONI again in another strong El Niño.

[Stormchaserchuck1]

4 minutes ago, 40/70 Benchmark said:

You are misunderstanding me....I understand what RONI is...it's not the reading itself that I am concerning myself with. It's what it represents....we WANT the El Niño to correlate to the North Pacific pattern, so having the RONI lag the ONI does not mean that it's a "weaker" El Niño...it means that there is another force, likely of cool ENSO ilk,  competing with the El Nino, and it's not forcing the north Pac pattern to a degree commensurate with the ONI intensity. If it were simply a weaker El Niño....it's probably more west-based and the Aleutian low is thus further west, which is favorable....but a lower RONI may mimic a west-based in the SST pattern, but actually have so much warmth in the western Pacific as to introduce more MC forcing than is typical in a potent El Niño. 

We'll see what happens have a lower RONI again in another strong El Niño.

Yeah, I think it will stay around -0.5c lower for the duration of the event. 

The big cold season 500mb low has been trending less and less intense in the progression of Strong Nino's for the last 70 years. Will be interesting to see if this one stays weak like 23-24. 

[40/70 Benchmark]

Just now, Stormchaserchuck1 said:

Yeah, I think it will stay around -0.5c lower for the duration of the event. 

Probably, so I am willing to bet it will stink, aside from maybe one great storm. I  don't feel as optimistic after seeing that RONI vs ONI relationship, as I was already leery of that after 2023.. Still plenty of time to and data to consider, though. I do wonder if we see that gap begin to close, though with the changes underway in the Pacific..that maybe what we need.

[Stormchaserchuck1]

On 3/27/2026 at 8:46 AM, Stormchaserchuck1 said:

^El Nino by itself is usually cooler in the Summer in the Great Lakes, Upper Midwest, and Northeast

Before a later in the year peak is stronger

Will this be a cooler Summer??

[Stormchaserchuck1]

On 3/27/2026 at 12:21 PM, Stormchaserchuck1 said:

March +NAO.. 2026 will probably have ~+2 NAO. It precedes warm CONUS conditions the following Winter in the northern 1/2 fwiw

March monthly NAO crushed it.. +2.69 for the month. Number 2 highest March NAO on record was +1.85

It also beat the most negative month of March on record, 1962, -2.47.

[roardog]

2 minutes ago, Stormchaserchuck1 said:

Will this be a cooler Summer??

I feel like the changes in the Pacific after the mid 2010s also took away the cooler summers. 

[Stormchaserchuck1]

4 minutes ago, roardog said:

I feel like the changes in the Pacific after the mid 2010s also took away the cooler summers. 

It certainly seems like it, some places around here were in the 90s yesterday. We had mid to upper 80s in early March. Jan 26, 2024 DC hit 80 degrees. A lot of very impressive spikes in the past few years. Summer is a season where wavelengths relax so the general pattern (warming) is more prevalent. 

Not to mention 3 of the mostly anomalously warm months on record for CONUS happened this Winter

[roardog]

7 minutes ago, Stormchaserchuck1 said:

It certainly seems like it, some places around here were in the 90s yesterday. We had mid to upper 80s in early March. Jan 26, 2024 DC hit 80 degrees. A lot of very impressive spikes in the past few years. Summer is a season where wavelengths relax so the general pattern (warming) is more prevalent. 

Not to mention 3 of the mostly anomalously warm months on record for CONUS happened this Winter

I always associated El Niño with a cool summer, a cold fall that turns mild in December and then can go either way after that depending on strength, location, etc. 

2014 did that(at least over here), 2009 had the cold October after a very cool summer and 2006 seemed to follow the Nino script also. But the 15-16 Nino did not and they haven’t since. 

[Stormchaserchuck1]

El Nino/+QBO December's:

6/6 months were warm in the Great Lakes/NE

[40/70 Benchmark]

1 minute ago, Stormchaserchuck1 said:

El Nino/+QBO December's:

6/6 months were warm in the Great Lakes/NE

Yea, looks like WPO is going to be key to salvage a decent northeast snowfall season...only 1982 wasn't a disaster, which has a -WPO.

[Stormchaserchuck1]

1 minute ago, 40/70 Benchmark said:

Yea, looks like WPO is going to be key to salvage a decent northeast snowfall season...only 1982 wasn't a disaster, which has a -WPO.

Luckily we can track that way ahead of time as Global SSTAs have a huge correlation with following season WPO

[40/70 Benchmark]

27 minutes ago, Stormchaserchuck1 said:

Will this be a cooler Summer??

I hope so.

[40/70 Benchmark]

5 minutes ago, Stormchaserchuck1 said:

Luckily we can track that way ahead of time as Global SSTAs have a huge correlation with following season WPO

I'll bet we can salvage that...we just ended an incredible decade of predominately +WPO....it just flipped this past season, so probably due for continued regression there.

[Stormchaserchuck1]

Some big +NAO's lately. This is based around the day DC hit 80 mid Winter.. it had never gone 80 Dec-Feb before that. +3.5 NAO

Now we had a March +NAO that broke monthly records going back 75 years by +0.84! The end result? The most extremely anomalous ridge the US has ever seen. Big +NAO spikes are correlating with some warm extremes the last 3 years.