2026 ENSO Updates

[Ntxw]

MJO forecasts is looping back to the Pacific, and may loop back yet again. 200mb CHI charts show sinking motion returning to the MC region while re-igniting over the Pacific. Pretty good indicator background low frequency is shifting closer to El Nino mode.

[AJC3]

The first shoe has dropped and is from the BoM of Australia.

https://i.imgur.com/SNR3rQQ.jpeg

https://www.bom.gov.au/climate/ocean/outlooks/archive/20260328//plumes/sstOutlooks.rnino34.hr.png

https://www.bom.gov.au/climate/enso/?ni ... s=Overview

I'm not gonna lie to you, even though strong El Nino is looking more likely, I have a hard time believing we will get as as strong as the BoM forecasts, especially by September. What especially makes me want to partially throw this run out is a HUGE jump in the index from March to April. I'm sorry but I do not see that happening.

Since there's a dash between FEB-MAR, that makes me think that their MAR value (about -0.55C) is a hindcast/nowcast that was used to initialize that run of the ACCESS-S2, rather than an actual analyzed data point. That point on the graph doesn't even match their own NINO 3.4 value (-0.42C) shown in the text, and moreover, CPC's latest update from 30 MAR had that value as -0.3C. I know BoM/CPC have different ENSO thresholds, but is there also a fundamental difference in how actual ENSO values are calculated? In any event, if you plot the CPC value on the chart, then the BOM model change from MAR-APR doesn't look nearly as odd. Just some food for thought.



Caveat: There might be something I'm not taking into account about how the indices are calculated.

[DorkyMcDorkface]

I've learned a lot about ENSO over the past 5 years but I have a question: when was the last time we've had a strong Niño event so suddenly after another? Seems like they occur once every decade or so, but this time around we're getting two in rather quick succession. I also wonder because the last time it was understandable with a triple-dip moderate Niña event the first half of the 2020s but this time around we've had two weaker Niña events (according to RONI, ONI was nearly merely cool-neutral for 2024-25). What's the case this time around?

[Ntxw]

I've learned a lot about ENSO over the past 5 years but I have a question: when was the last time we've had a strong Niño event so suddenly after another? Seems like they occur once every decade or so, but this time around we're getting two in rather quick succession. I also wonder because the last time it was understandable with a triple-dip moderate Niña event the first half of the 2020s but this time around we've had two weaker Niña events (according to RONI, ONI was nearly merely cool-neutral for 2024-25). What's the case this time around?

One aspect we have to think about is that the warm pool over the western Pacific has been prolific in the 2020s. The warm water expanse has been incredible El Nino or La Nina. 2023-2024 did not fully disperse this warm pool. It's physics, if the bathwater is continuously hot, any shift will allow it to move despite what ENSO was. This is something we don't fully understand with global oceans warming rapidly. A theoretical idea one could ask, since 2023-24 did not fully behave like a traditional Nino, could it be reason why we're seeing a more traditional one form so close?

1963-64, and then 1965-66 had a moderate and strong Nino pretty quickly.