Weather Blog

Odds of an El Niño this winter drop by 15%

Odds of an El Niño this winter drop by 15%

Maybe El Niño isn't such the slam dunk it seemed a few months ago?

Forecasters with NOAA's Climate Prediction Center – the people in charge of watching for El Niño and La Nina, among many other things – have dropped their chances of El Niño developing this fall and winter to 65 percent from 80 percent.

Granted, that's like saying a football team that was a 14 point favorite to win is now just an 11 point favorite – still a pretty good chance it'll happen. Just not as much as before.

But if nothing else, the trend is interesting.

Emily Becker with NOAA says while ocean temperatures warmed up this spring and gave signals of a budding El Niño, the atmosphere hasn't really responded in kind. And since then in recent weeks, the ocean in the central-eastern Pacific region have cooled a bit.

So, why still a 65% chance then? Becker says the forecast models used to predict these long range trends for El Niño/La Nina are still pretty adamant an El Niño will form:



And the models did pick up on the current tick downward in ocean temperatures, so forecasters feel the models have a good read on the situation.

But it was enough to at least bring the odds down a bit.

It would be an important development if it did fizzle. El Niño winters are typically warmer and drier than usual and at least for Western Washington, typically mean a lower-than-normal mountain snowpack, so in that sense, it'd be nice not to have that kind of potential drag on mountain snowfall. On the other hand, it'd also be less likely that California would have a wet winter and they could sure some rain right now (as long as it's not in big bunches).

We've been down this El Niño-teasing road before, and actually it wasn't even that long ago. The spring/summer of 2012 was also screaming that El Niño was going to form in the autumn – the oceans were warming and all signs pointed to yes. Then... everything stopped, El Niño fizzled, and the winter ended up neutral instead.

Could it happen again? Sure. As Becker wrote on the NOAA blog:

"While the forecast chance has decreased, there is always plenty of uncertainty on just what will happen. As we’ve said, even a forecast of 80% for an event means there’s a 1-in-5 chance that the event won’t happen; now, while we’re estimating a 65% chance that El Niño will happen, that means a roughly 1-in-3 chance that it won't."

Becker's blog is a great read and I'd highly recommend giving it a read if you want to get in to the gory meteorological details behind the drop in El Nino odds.