2026-2027 Record-breaking El Nino

[KChuck]

8 hours ago, mitchnick said:

Euro seasonal latest snowfall change this run vs last courtesy Weather Will in the MA forum. No complaints from me!

 

What's with the snow hole in central North Carolina??? 

[mitchnick]

1 hour ago, michsnowfreak said:

This is the actual anomaly map.

 

25 minutes ago, KChuck said:

What's with the snow hole in central North Carolina??? 

That map I posted was the run-to-run change between September and October Euro seasonal.  The actual snowfall anomaly map is above and that shows AN in that location. 

[40/70 Benchmark]

9 hours ago, mitchnick said:

Euro seasonal latest snowfall change this run vs last courtesy Weather Will in the MA forum. No complaints from me!

 

Looks about the same for me....about 15" below average seems reasonable. No complaints.

[40/70 Benchmark]

8 hours ago, forkyfork said:

is roni going to lower the amount of latent heat that gets released into the climate system and trapped by carbon dioxide? is roni going to keep an eastward displaced north pacific low from flooding the continent with maritime airmasses all winter?

No to the first, but as far as as the second....not the RONI itself, but the disconnect that it represents may to an extent...and that doesn't necessarily mean colder in the east, either.

[40/70 Benchmark]

7 hours ago, bluewave said:

RONI is not meant to be used for the absolute intensity of this event. It’s more about gradients and storm tracks. With something this historic, it’s the absolute temperatures and water vapor increase that matter which is better reflected by ONI.

 

They why did the 2023 El Niño have a very meager GOA low presence despite a peak ONI of 2.0?

[ensonerd1233e343]

On 10/6/2026 at 6:56 PM, 40/70 Benchmark said:

I strongly disagree.

In the tropical atmospheric response or just the oni? 

Or both

[40/70 Benchmark]

16 minutes ago, ensonerd1233e343 said:

In the tropical atmospheric response or just the oni? 

Or both

That climate change isn't playing a part in this El Nino...the immense OHC that has built up in the west Pacific has absolutely played a rpole in trggiering this response. 

[ensonerd1233e343]

10 minutes ago, 40/70 Benchmark said:

That climate change isn't playing a part in this El Nino...the immense OHC that has built up in the west Pacific has absolutely played a rpole in trggiering this response. 

Yes but im asking about which part of the el nino the absolute tempature (oni) or the gradients and atmospheric response ( mei eqsoi roni)

[40/70 Benchmark]

51 minutes ago, ensonerd1233e343 said:

Yes but im asking about which part of the el nino the absolute tempature (oni) or the gradients and atmospheric response ( mei eqsoi roni)

Which part did CC contribute to? All of it....the sole purpose of ENSO is to redistribute heat, so the rapid warming of the climate is acutely relevant in that respect.

[MJO812]

DT

[OSUmetstud]

16 hours ago, LakePaste25 said:

I think it’s worth tracking, but proceed with caution given the known ECMWF weak PV bias. 

Definitely but that graph also has the ecmwf model climate and the prediction is weaker than that, too. A weaker pv and a tendency towards blocking in a very strong nino year doesnt seem too surprising to me. 

 

[bluewave]

12 hours ago, 40/70 Benchmark said:

They why did the 2023 El Niño have a very meager GOA low presence despite a peak ONI of 2.0?

Probably a secondary underlying factor overlapping with both ONI and RONI. Since we have had much stronger GOA lows in the past with similar RONI values.

1986-1987 had a much more expansive GOA-NP low than 2023-2024 with both RONI values near +1.5.

Also note the much weaker GOA low in 2015-2016 than 1997-1998 despite identical RONI values of +2.3.

My guess is this is a similar phenomenon we have been observing with all ENSO states. The 500mb ridges have become much stronger and expansive relative to the low pressure troughs.

These stronger ridges have been driving the persistent -PDO and +AMO. So the warmer SSTs in the mid-latitudes are probably helping to cause a feedback loop. This area is outside the RONI band in the tropics.

[chubbs]

The current ENSO longitude Index lines up better with other years using ONI vs RONI. A couple of possible explanations: 1) This nino is unusually east-based for its strength and/or RONI isn't a great strength indicator for this particular nino.  In any case this year is an outlier.

[bluewave]

The Euro going into late winter and spring still has ENSO values warmer than any event had during the Nov-Dec peaks in the past. 
 

 

[40/70 Benchmark]

2 hours ago, bluewave said:

Probably a secondary underlying factor overlapping with both ONI and RONI. Since we have had much stronger GOA lows in the past with similar RONI values.

1986-1987 had a much more expansive GOA-NP low than 2023-2024 with both RONI values near +1.5.

Also note the much weaker GOA low in 2015-2016 than 1997-1998 despite identical RONI values of +2.3.

My guess is this is a similar phenomenon we have been observing with all ENSO states. The 500mb ridges have become much stronger and expansive relative to the low pressure troughs.

These stronger ridges have been driving the persistent -PDO and +AMO. So the warmer SSTs in the mid-latitudes are probably helping to cause a feedback loop. This area is outside the RONI band in the tropics.

Yes, I think that it definitely part of it, but some more than others...I think it's also important to view the RONI relative to the ONI, rather than in a vacuum.

A crude, but effective way to distinguish these more recent MC oriented El Nino seasons is to utilize the delta between the RONI, which separates ENSO-related warming from general background warming attributable to climate change, and the ONI. The positive ONI/RONI ratio in the four most recent El Nino seasons, which denotes a RONI lagging the ONI, is indicative of surplus of warmth over the western Pacific relative to the eastern Pacific, which is the very essence of the mechanism that focuses the convection there.

 

Notice how the ONI and RONI are equal in 1997 and the ONI is actually higher in 1986-1987. However, in 2016, the RONI is significantly lower and the spread is even greater in 2023, with a RONI value .6 lower than than the ONI.

            ONI       RONI    RATIO 

2023:   2.1        1.5        0.6

2018    1.1         0.8       0.3

2016    2.8         2.4       0.4

2014   0.8          0.6       0.2

2009   1.6          1.6       0.0

2006   0.9          0.9       0.0

2004   0.7          0.9      -0.2

2002   1.3          1.5      -0.2

1997   2.4          2.4      0.0

1994   1.1          1.4      -0.3

1991   1.7         2.3      -0.6 

1987   1.7         1.6      -0.1

[EastonSN+]

On 10/6/2026 at 3:23 PM, EastonSN+ said:

The track of the 1992 storm can be found here. Looks like the primary tracked inland to the DelMarva, stalled, then moved out which is why it rained in the beginning in SNE. Seems very different than the recent noreaster and if 92 followed the recent noreaster's track we would have been buried down to the coast at least.

https://www.jdjweatherconsulting.com/dec-11-12-1992

 

Looking at this in more detail, the 1992 storm was never an ideal track for all snow in NYC/LI and SNE. This past event had a much more favorable track.

[40/70 Benchmark]

1 hour ago, OSUmetstud said:

Definitely but that graph also has the ecmwf model climate and the prediction is weaker than that, too. A weaker pv and a tendency towards blocking in a very strong nino year doesnt seem too surprising to me. 

 

All guidance has a weak PV....check out the UK data.  Blocking in a stronger El Nino isn't too surprising, but it is given the state of the stratosphere and solar cycle....I still feel like it's overdone in the seasonal mean, but I have no issue with a blocky second half overall.

[40/70 Benchmark]

9 hours ago, MJO812 said:

DT

I saw that...he's swinging in towards my early hedge. Usually he likes to tout a more rapid weakening of El Nino amongst data, but I don't think that is the case, so it's probably the EURO in general looking snowier.

[EastonSN+]

14 hours ago, mitchnick said:

 

That map I posted was the run-to-run change between September and October Euro seasonal.  The actual snowfall anomaly map is above and that shows AN in that location. 

Pretty cut and dry from a historical perspective. Strong El ninos are either warm and relatively snowless or have a short snowy period inclusive of a major event. If we get that period then NC can easily reach above average snowfall.

Basically an all or nothing HR hitter coming to the plate knowing 3 strikeouts are inevitable. However always that chance for a HR in the 4th AB.

[bluewave]

11 hours ago, 40/70 Benchmark said:

That climate change isn't playing a part in this El Nino...the immense OHC that has built up in the west Pacific has absolutely played a rpole in trggiering this response. 

A big question going forward is what does the future relationship look like in regard to the equatorial trade winds vs WWBs following such an enormous warm pool push from the WPAC to EPAC?

[mitchnick]

1 hour ago, EastonSN+ said:

Pretty cut and dry from a historical perspective. Strong El ninos are either warm and relatively snowless or have a short snowy period inclusive of a major event. If we get that period then NC can easily reach above average snowfall.

Basically an all or nothing HR hitter coming to the plate knowing 3 strikeouts are inevitable. However always that chance for a HR in the 4th AB.

I agree about the HR hitter coming to bat, but I  don't think we can rule out other light or moderate chances with the advertised precip anomalies on all modeling.

[LakePaste25]

1 hour ago, 40/70 Benchmark said:

Yes, I think that it definitely part of it, but some more than others...I think it's also important to view the RONI relative to the ONI, rather than in a vacuum.

A crude, but effective way to distinguish these more recent MC oriented El Nino seasons is to utilize the delta between the RONI, which separates ENSO-related warming from general background warming attributable to climate change, and the ONI. The positive ONI/RONI ratio in the four most recent El Nino seasons, which denotes a RONI lagging the ONI, is indicative of surplus of warmth over the western Pacific relative to the eastern Pacific, which is the very essence of the mechanism that focuses the convection there.

 

Notice how the ONI and RONI are equal in 1997 and the ONI is actually higher in 1986-1987. However, in 2016, the RONI is significantly lower and the spread is even greater in 2023, with a RONI value .6 lower than than the ONI.

            ONI       RONI    RATIO 

2023:   2.1        1.5        0.6

2018    1.1         0.8       0.3

2016    2.8         2.4       0.4

2014   0.8          0.6       0.2

2009   1.6          1.6       0.0

2006   0.9          0.9       0.0

2004   0.7          0.9      -0.2

2002   1.3          1.5      -0.2

1997   2.4          2.4      0.0

1994   1.1          1.4      -0.3

1991   1.7         2.3      -0.6 

1987   1.7         1.6      -0.1

Once we see that subsurface cool pool out in the W pac upwell some more (probably sometime later this winter), we could see RONI catch up to ONI.

 

[40/70 Benchmark]

3 minutes ago, LakePaste25 said:

Once we see that subsurface cool pool out in the W pac upwell some more (probably sometime later this winter), we could see RONI catch up to ONI.

 

That would make sense to me and is consistent with my forecast.....RONI should still lag in the seasonal mean by around .2 to .4, but may get closer than that late.

[40/70 Benchmark]

18 minutes ago, mitchnick said:

I agree about the HR hitter coming to bat, but I  don't think we can rule out other light or moderate chances with the advertised precip anomalies on all modeling.

It's also important not to be too dialectical in our thought process, as it's human instinct to focus on snow/rain as binary events, but the truth is that in all likelihood they often won't be this season. Several 2-5"ers followed by IP and rain still counts towards the seasonal total.

[forkyfork]

1 hour ago, EastonSN+ said:

Pretty cut and dry from a historical perspective. Strong El ninos are either warm and relatively snowless or have a short snowy period inclusive of a major event. If we get that period then NC can easily reach above average snowfall.

Basically an all or nothing HR hitter coming to the plate knowing 3 strikeouts are inevitable. However always that chance for a HR in the 4th AB.

none of the east coast storms will be cold enough for snow

[forkyfork]

1998 couldn't get a snowstorm because the pacific jet would not allow enough cold to build in canada. this event is even more unfavorable than that one

[forkyfork]

all rain

[forkyfork]

drip drop

[40/70 Benchmark]

2 minutes ago, forkyfork said:

all rain

I'm surprised, usually low pressure over SE Canada works out well on the east coast.

[40/70 Benchmark]

How did this one work out in SNE?