Thursday, June 8, 2017

El Nino Next Winter?

Now that we are in June, our ability to forecast El Nino/La Nina is substantially improved.

There is, in fact, a "spring forecast barrier" for this phenomenon, with very little skill during the late winter and spring, but greatly increasing skill from June forward in predicting the character of the next winter.

El Nino and its opposite sibling, La Nina, have a substantial impact on the nature of our winter weather, with El Nino "weighting the dice" for warmer conditions with less snow.

The key parameter used to keep track of El Nino/La Nina is the sea surface temperature anomaly (difference from normal) in the central tropical Pacific (the Nino 3.4 region, see map).  When sea surface temperatures are .5C or more warmer than normal in that region, we term it an El Nino, between .5C and -.5C Neutral, and when more the .5C colder than normal, La Nina.


As you can see in the next figure, there were below-normal temperatures last fall (La Nina), which switched to warmer than normal conditions during the spring leaving us in marginal El Nino conditions.


The latest NOAA Climate Prediction Center forecast for this winter (see below) is for equal chances of El Nino and Neutral conditions.


And the recent ensemble forecasts of the NOAA CFSv2 seasonal ocean/atmosphere model projects that conditions will cool towards Neutral conditions this fall.


A collection of many forecast center projects, using a variety of models, predicts very modest warming on average.


So what is the bottom line?   We are unlikely to have La Nina next year.  Similarly a strong El Nino is not in the cards.  A weak El Nino or warm Neutral conditions is most likely.  

For the Pacific Northwest, this suggests we might expect a normal snowpack next winter, but not as bountiful as this year.   But keep in mind, the El Nino/La Nina connection only explains about a third of the year to year variability in our weather.

4 comments:

TheWildLine said...

La Nina is already in the loop, warm with barely snow. I've been studying sun spots and wind patterns and it's all lining up soon.

windlover said...

Maybe if it's a neutral winter one of those big wind storms will actually happen, instead of fizzling out. Plus, haven't we had some pretty good cold snaps and arctic blasts during neutral years, or even weak el ninos? It was nice to have a real winter this past year with cold and snow. I love stormy, snowy fall and winters!!!

Thecatguy93 said...

What's with rooting for big windstorms? I don't get it. People inevitably are killed in these storms and millions of dollars in damage occurs. Nothing quite like rooting for death and destruction..

Gordon said...

IF the ENSO explains about 1/3 of the influence, what are the other factors that we need to take into account?