Is a Strong El Nino FINALLY coming?

Last year about this time, the media was abuzz about a Super El Nino that would hit over the past winter (2014-2015).  Dramatic predictions were made for drought in the Pacific Northwest and heavy rains over southern California.

Unfortunately for the prognosticators, an official El Nino didn't occur although the waters in the tropical Pacific were slightly above normal.   Perhaps, we should have called it El Tepid.

But during the last few months the situation has altered substantially with temperatures in the central and eastern tropical Pacific surging upwards.   NOAA and Australian forecasters are now saying we are in an official El Nino and it appears it will become moderate or strong this year.

Let me show the details.  Here are plots of the sea surface temperature (SST) anomalies (differences from normal) for four critical zones in the topical Pacific. They are warming, with many of them being the warmest over the past year.  The usual definition for El Nino calls for a warm anomaly in the Nino 3.4 area of at least .5C for three consecutive months.  We got that now.

Here is a map of the SST anomalies for the past month.  Warm water (dark orange and red) stretching from the central Pacific to the coast of S. America.   You can also see the crazy warm water off our coast.

 NOAA has placed a series of buoys along the equatorial Pacific to keep track of the ocean temperatures below the surface.  These buoys show quite warm water extending 100-200 meters beneath the surface.  This figure shows an east-west cross section across the central Pacific of the underwater temperatures.  Red is much warmer than normal.

Bottom line:  we have now entered El Nino territory.  Based on a collection of models, NOAA's Climate Prediction Center (CPC) is going for El Nino conditions the remainder of this year (see their probabilistic forecast below).   Roughly 70% chance  this summer and about 60% chance next winter.  But this time of the year you have to be careful, with the quality of the winter forecasts improves radically by July and August.

The National Weather Service's primary seasonal prediction system, CFSv2, is based on running  weather/ocean forecast models out 9 months.    Its forecast is emphatic and confident (see below):  a strong El Nino will develop this summer and extend into next winter.

So what are the implications for the Northwest if a strong El Nino is in place next winter?  

We tend to be warmer than normal with less snow in the mountains (and much less snow in the lowlands).  Less stormy.  The good thing is that a typical strong El Nino year generally has more snow than the freaky year we just finished.  But this is not good news for ski areas.   On the positive side, El Nino years tend to bring more precipitation than normal to central and southern California.   And guess what?  The latest NOAA CFS model is showing exactly that for next October through December (see below).

Let me stress that there is a lot of uncertainty with this forecast and the models were not good last year.  But this year's warm water is more extensive than last and the models are more in agreement.  If the forecasts hold into mid-summer, our confidence in the strong El Nino prediction will be substantially enhanced.  So hold on but you decide on buying that ski pass at your favorite resort.