Super El Niño Next Winter?

Recently a weather outlook has been making the rounds. The Washington Post meteorologists caught wind of a professor positing about the potential for a super El Niño this coming winter, possibly the strongest in 140 years. They’ve written stories about it in March and April. For the record, the meteorologists at the Capital Weather Gang as well as the professor they reference are top notch, and I’m not writing this blog to disagree with them. I just wanted to add a few additional facts. 

El Niño, as most of you probably know, is a warming of the ocean in the Pacific along the equator.  I won’t bore you with how this affects our weather in the Northwest.  But 9 times out of 10, El Niño brings mild winters to our area.  

So how is El Niño measured?  A rectangular area in the Pacific is chosen and named Nino 3.4, which is the light blue area on the map below (image from the ECMWF webpage).



Computer climate models predict ocean temperatures.  Those temperatures are averaged over that light blue box to arrive at a single number.  All of those forecasts are gathered and presented on the chart below.


Each thin colored line is a different computer forecast.  If the lines go above the dashed 0.5 line, then they are predicting an El Niño.  The higher they go, the stronger the El Niño they are predicting.  The thick reddish line is an average of the forecasts.  The average forecast is for weak El Niño conditions by the April-May-June (AMJ on the graph) timeframe.  They go on to expect a strong El Niño (1.5 value) by this coming autumn.  There are a couple of computers that predict an even stronger El Niño.  Main point: just about all of the computers are forecasting an El Niño this coming winter. But nothing we haven’t seen before. 

One forecast that’s not on that chart is the ECMWF, which actually runs 50 different forecasts.  Here’s their latest outlook.



Whoa. That is crazy. There’s no average line on that graph, but it would probably be somewhere around 2.5 by this coming autumn, with a few predictions of 3.5. This is the graph that the professor and WaPo are reacting to. And if it verifies, it would probably be the strongest El Niño since before 1950.  

The record El Niño was 2015-16 with a peak value of 2.8C. However, it’s worth noting that while today’s ocean temperatures are measured by satellites, along with some ships and moored buoys, in the 1950s and 60s (and probably 70s) no such satellite measurements existed, so the accuracy of these early ocean temperatures is more questionable. 

These computer forecasts are made each month. And they are also verified. And when I was in the field it was well known that the poorest verifying forecasts were made in the Northern Hemisphere spring. This is possibly due to the transition that the ocean is undergoing at this time of year. So keep that in mind. 

So let’s look back at how the ECMWF did last year at this time. Here’s its forecast from April 2025, and the blue line shows what really happened. 


It really wasn’t even close to accurate. While ocean temperatures cooled, just about every ECMWF forecast was for warmer conditions. 

In April of 2024, it did much better, but ocean temperatures had already been cooling for several months, so it wasn’t as difficult of a forecast. 

From April 2023, the forecast was also good. But like 2024, the ocean was already warming impressively, so the forecast was just for things to continue.



Lastly in 2022, the ocean stayed colder, but the ECMWF expected it to warm. 





So all of that just to drive home the point that these El Niño outlooks aren’t always right.  I know, big shock. But in today’s clickbait culture, we see a headline and believe it, even passing it on to our friends. 

Take aways:
  • Nearly every climate model is forecasting an El Niño for the coming winter. 
  • El Niño almost always brings mild winters to the Northwest. 
  • Some computer forecasts call for a strong El Niño this winter, possibly record breaking.  
  • Computer climate forecasts struggle more at this time of year, but usually improve their accuracy during the summer. 










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