2026 ENSO Updates

[Dean_175]

Historic data of RONI since 1952 has 26 El NIño events and 28 La NIñas.

https://ggweather.com/enso/roni.htm

The table at the top that lists each year by strength seems to follow the old ONI and should be updated as it does not follow the table on the bottom with the indices.

Anyways, some of the most notable changes are: 2023-24 is down to a moderate El Niño, 1991-1992 is now a super/very strong El Niño according to RONI, 1982-1983 is the strongest El Niño measured by RONI (above 97 and 15), and 1972 should be classified as a very strong El Niño now.

1991-1992 stood out to me as the most surprising difference vs regular ONI. An increase from 1.7C in ONI to 2.3C in RONI is quite the jump. Perhaps the global cooling due to Mount Pinatubo gave RONI a significant boost as such cooling may be expected to have a larger effect on tropical surface water temperature than on the equatorial subsurface waters relevant for ENSO dynamics. This would also explain the boost that 1982 got from 3rd strongest to 1st, as volcanic cooling (from El Chichon) was also present during that event.

That 2023 fell so much compared to other El Niño events strongly suggests/confirms that globally warm tropics were indeed the mechanism behind the discrepancy between the very high raw ONI observed that year and the lack of robustness of atmospheric coupling observed.

[cycloneye]

Is a matter of time when the flip to neutral and eventually to El Niño comes but the only question is how strong it will be.

[jconsor]

Machine learning models like LIM are much less enthusiastic on a strong El Nino this summer-fall than dynamical ones.

 https://x.com/yconsor/status/2016239157664792672

[Yellow Evan]

For the members who know about this, have a question. The Southern Hemisphere has been very active so far with ACE well above average. https://tropical.atmos.colostate.edu/Realtime/

Being very active has an effect on ENSO?

SIO activity is correlated with a cold Indian and Atlantic Ocean and a +PDO/PMM and -ENSO conditions. The SIO has 5 majors already. All but the +PDO exist as of this typing.

[cycloneye]

The CFSv2 model has been going up in a steady way in the past few weeks and now proyects moderate El Niño for ASO.

[cycloneye]

That is Interesting.

 https://x.com/WorldClimateSvc/status/2016959747472183335

[Kingarabian]

A trade burst in the next 30 days wouldn't be detrimental to a possible El Nino.

[Ntxw]

A trade burst in the next 30 days wouldn't be detrimental to a possible El Nino.

ENSO usually has one last gasp in February historically. This is probably that for La Nina, what will matter is come spring and WWBs. The warm pool is already east of where it was.

[DorkyMcDorkface]

A trade burst in the next 30 days wouldn't be detrimental to a possible El Nino.

Frequent pauses/interruptions in westerlies could still slow development in the short term (especially if they're relatively strong in magnitude) but I don't think that drastically alters the direction we're headed when it comes to Niño formation this year, and if early guidance is correct it could very well be on the stronger side of things (although this is not a guarantee pre-SPB obviously)

[Ntxw]

I believe an aspect that we will need to watch is forcing over the MC. The recent El niños and warm Enso events have been interfered by this feature of consistent warm anomalies over Indonesia that has created destructive interference with El Nino events. Should the warm pool be further east and able to overpower then we could look at a more traditional El Nino like prior to 2015. This will have implications both on the roni and tropical activity across the globe. Should we have interference by the MC then the Atlantic will likely be more active than usual as it has been since that tends to keep rising motion out of the Pacific, if not then we will look at a more typical El Nino progress atmospherically that will interfere with the basin. Just food for thought.

[cycloneye]

I believe an aspect that we will need to watch is forcing over the MC. The recent El niños and warm Enso events have been interfered by this feature of consistent warm anomalies over Indonesia that has created destructive interference with El Nino events. Should the warm pool be further east and able to overpower then we could look at a more traditional El Nino like prior to 2015. This will have implications both on the RONI and tropical activity across the globe. Should we have interference by the MC then the Atlantic will likely be more active than usual as it has been since that tends to keep rising motion out of the Pacific, if not then we will look at a more typical El Nino progress atmospherically that will interfere with the basin. Just food for thought.

When you say it may have implications on the RONI, what do you mean?

[Ntxw]

I believe an aspect that we will need to watch is forcing over the MC. The recent El niños and warm Enso events have been interfered by this feature of consistent warm anomalies over Indonesia that has created destructive interference with El Nino events. Should the warm pool be further east and able to overpower then we could look at a more traditional El Nino like prior to 2015. This will have implications both on the RONI and tropical activity across the globe. Should we have interference by the MC then the Atlantic will likely be more active than usual as it has been since that tends to keep rising motion out of the Pacific, if not then we will look at a more typical El Nino progress atmospherically that will interfere with the basin. Just food for thought.

When you say it may have implications on the RONI, what do you mean?

RONI takes into consideration warming sustained in other regions, while this helps, doesn't guarantee the other areas across the tropics will be more anomalous in this (or any other events.) It's also possible an eventual Nino event will be warmer than other regions, we can't just assume the rest of the globe warms while ENSO is stagnant.

[cycloneye]

The recent update from the graphic and animation shows how the warm waters keep advancing to the east and reach the surface, while the cold waters keep shrinking.





 https://x.com/akshaydeoras/status/2017933524502806731

[cycloneye]

CPC in the 2/2/26 weekly update has niño 3.4 at -0.8C, however the warmer waters continue to expand and to warm in depth.

https://www.cpc.ncep.noaa.gov/products/ ... ts-web.pdf

[Kingarabian]

Should see the SOI rise and enhanced dateline trades. MJO going into the IO soon. Question is if we'll see an IO WWB or not.

[cycloneye]

Should see the SOI rise and enhanced dateline trades. MJO going into the IO soon. Question is if we'll see an IO WWB or not.

If there is no WWB, then the transition to neutral and later to El Niño is going to be delayed.

[zzzh]

GFS going crazy again with another extreme WWB

Boom.

https://i.imgur.com/Y3xWldX.jpeg

Classic long range gfs bias

[Kingarabian]

Should see the SOI rise and enhanced dateline trades. MJO going into the IO soon. Question is if we'll see an IO WWB or not.

If there is no WWB, then the transition to neutral and later to El Niño is going to be delayed.

Actually if there's an IO WWB and then there's no March dateline WWB then that's a telling sign that the atmosphere is still favoring La Nina which could drastically change El Nino chances.

[cycloneye]

Should see the SOI rise and enhanced dateline trades. MJO going into the IO soon. Question is if we'll see an IO WWB or not.

30 day SOI index very positive right now.

[cycloneye]

Added the RONI data to the first post of thread.

https://www.cpc.ncep.noaa.gov/products/ ... enso/roni/