2026 ENSO Updates

[cycloneye]

Remains a potent WWB on the models. Looks like it'll start this week and likely continue until the end of the month.

[cycloneye]

This upcomming WWB means business.


Eric Webb
@webberweather
Good lord.

This Westerly Wind Burst in the Tropical West Pacific late month is so strong on the Euro weeklies it's wrapping the scale

If there was any doubt we weren't getting an El Niño later this year, this just about does it.

 https://x.com/webberweather/status/2010446761731764416

[cycloneye]

Andy Hazelton with the C35 multi-model.

@AndyHazelton
A solid majority of ensemble members from the C3S multi-model forecasts have a solid El Niño developing by early summer. The forecast looks comparable to or maybe even slightly warmer than the forecast from January 2023, and in reality ENSO verified on the warm side that time. The atmospheric coupling also appears to be well-established by then, with enhanced rising over the Pacific and enhanced shear/TUTT activity across the Atlantic.

 https://x.com/AndyHazelton/status/2010355273441890480

[cycloneye]

There are still mixed signals on ENSO today as the weekly CPC update is released. Niño 3.4 is more colder than last week at -0.8C and the 30 day SOI index continues very positive.

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






On the other hand, the 300 meter depth is warming at a faster pace meaning the WWB is already having an effect on that.

[cycloneye]

Boom!!

 https://x.com/AndyHazelton/status/2010733244585505068

[Kingarabian]

Interesting enough this MJO pulse won't be as strong as the ones we saw in 2014 and 2015 that superceded those strong WWBs. So there must be an additional precursor involved.

[Kingarabian]

There are still mixed signals on ENSO today as the weekly CPC update is released. Niño 3.4 is more colder than last week at -0.8C and the 30 day SOI index continues very positive.

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


https://i.imgur.com/g6uUWyF.jpeg

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

On the other hand, the 300 meter depth is warming at a faster pace meaning the WWB is already having an effect on that.

https://i.imgur.com/5Hvg2v7.jpeg

It'll start tanking in about a week or so but until the extra tropics lock in to +ENSO, expect some volatility.

[Yellow Evan]

SOI isn't the best ENSO indicator with how off equatorial the index is based off of and not sure why this forum talks about it so much in the year of our lord 2026. The fundamentals of ENSO haven't really changed over the last week with a WPAC WWB still modeled, budding +PMM, classic pre-Nino sub-surface, and fairly cool Atlantic and Indian Ocean.

[cycloneye]

The blues keep shrinking.

[Kingarabian]

SOI isn't the best ENSO indicator with how off equatorial the index is based off of and not sure why this forum talks about it so much in the year of our lord 2026. The fundamentals of ENSO haven't really changed over the last week with a WPAC WWB still modeled, budding +PMM, classic pre-Nino sub-surface, and fairly cool Atlantic and Indian Ocean.

I disagree that it isn't one of the best ENSO indicators. I agree it needs to be used or understood better. As long as its used correctly, It's probably the most consistent indicator thus making it the best present and near term indicator IMO. It's the SO part of ENSO.

In this case the 30/90 day SOI is spot on. The MJO has just finished up moving through the Indian Ocean and La Nina has transitioned to cool neutral.

Daily SOI is extremely noisy and shouldn't be used at all. But a string of daily values can give you hints in where the 30 day SOI will end up. 30 day SOI will basically tell you how the MJO is affecting things and where. 90 day SOI will tell you where ENSO stands.

[cycloneye]

@WorldClimateSvc
Comparing the latest
@CopernicusECMWF
Niño3.4 forecast to 3 years ago (leading into the 2023-24 major El Niño)

The Feb-June rate of warming is nearly the same, but we have a slightly warmer starting point this time.

Skill at this time of year is modest, so uncertainty lingers.

 https://x.com/WorldClimateSvc/status/2011210319897772500

[Dean_175]

SOI isn't the best ENSO indicator with how off equatorial the index is based off of and not sure why this forum talks about it so much in the year of our lord 2026. The fundamentals of ENSO haven't really changed over the last week with a WPAC WWB still modeled, budding +PMM, classic pre-Nino sub-surface, and fairly cool Atlantic and Indian Ocean.

I disagree that it isn't one of the best ENSO indicators. I agree it needs to be used or understood better. As long as its used correctly, It's probably the most consistent indicator thus making it the best present and near term indicator IMO. It's the SO part of ENSO.

In this case the 30/90 day SOI is spot on. The MJO has just finished up moving through the Indian Ocean and La Nina has transitioned to cool neutral.

Daily SOI is extremely noisy and shouldn't be used at all. But a string of daily values can give you hints in where the 30 day SOI will end up. 30 day SOI will basically tell you how the MJO is affecting things and where. 90 day SOI will tell you where ENSO stands.

ESOI is a better indicator and is more strongly correlated to nino3.4. It is not exactly a leading indicator though. SOI/ESOI should still be expected to be positive as we transition out of the semi-La Nina. WWB events and favorable MJO do help charge the subsurface and generate downwelling Kelvin waves (leading indicators) and are often associated with short periods of change in the daily SOI values. However, I would not expect SOI or ESOI to reflect +ENSO until nino3.4 warms (or perhaps immediately before if there is a strong enough favorable MJO phase in the spring) The lack of negative ESOI likely was one reason that the borderline 2014 event was not declared by NOAA until the fifth consecutive ONI trimonthly had been achieved as the ESOI is one of the indices that is reflective of the state of the atmosphere. SOI is quicker to measure and describe than ESOI, however. Currently, I would not describe the atmosphere as being in a +ENSO state regardless of the WWB. It is in more of a transitional state, with stronger than normal trades to the east while the WWB is helping charge the warm pool and send some of that heat eastward below the surface. The full shift will happen when the SSTs stop having a Nina-esque signature.

To get an El Niño by late spring, we should start to see a lessening of Nina related dynamics- and that would include an decrease in SOI(though not necessarily to negative levels yet) and of course a warming below the surface (as is being observed). To get a strong El Nino later in the year, a strong MJO related pulse moving eastward from the west Pacific in spring to reinforce the current warm pool would be ideal.

[cycloneye]

The 7 day change from Coral Reef and OISST begin to show warming anomalies.

[Ntxw]

No doubt this WWB/MJO couplet is the terminus for La Nina. We'll likely need to see another significant WWB in the spring (March or April) to further get the base state to El Nino mode. Then an early summer WWB will determine future strength, but having this first (imo) increases the odds for a second the next round of MJO activity ~45-60 days as the WPAC warm pool has shifted eastward. Essentially constructively interfering with El Nino growth each pass.

[cycloneye]

I know the 30 day SOI is not a leading indicator but it continues to be very positive around +10. https://www.longpaddock.qld.gov.au/soi/ and I wonder about it being too positive if it has an effect.

[cycloneye]

@BenNollWeather
Upper-ocean heat content data for December showed that the West Pacific Warm Pool remained fifth warmest on record, despite some of its heat already being discharged eastward.

This warmth raises the ceiling on the potential strength of El Niño later in 2026.

 https://x.com/BenNollWeather/status/2012177773280870899



Interesting this reply.

@andrearomeo74
Very relevant data. The key point isn’t just elevated upper-ocean heat content, but how and when that energy is released.
If the eastward discharge remains fragmented or out of sync with the atmosphere, the impact on El Niño could be limited.
If it becomes dynamically coherent (winds, Kelvin waves, air–sea feedbacks), then the ceiling for a 2026 event truly rises.
For now, this is a signal of potential, not yet an outcome.


 https://x.com/andrearomeo74/status/2012216980170747951

[cycloneye]

@blizzardof96
This progression aligns with a mixed (i.e., basin-wide) La Niña termination, as depicted in Li et al. (2015), which shows SST warming first emerging in the eastern Pacific.

 https://x.com/blizzardof96/status/2012642481410838923

[cycloneye]

Why OISST and Coral Reef are very different?

[Kingarabian]

They're always different when there's cooling or warming of the SST anomalies. I believe its due to the method of reading the SSTs.

[Kingarabian]

WWB is ongoing... with arguably less amplitude than previously forecast. Still significant. Comes down to the next MJO pass during mid February to trigger a March WWB. That will be key.