October 22, 2012

A Faltering El Nino

The difference between a strong El Nino winter and a neutral winter (neither El Nino nor La Nina) can be a large one.

Strong El Nino winters are generally warmer and drier than normal. Less big storms.  Considerably less snowpack in the Cascades and little, if any, snow in the lowlands.

Neutral winters bring "normal" weather and have a bit of a twist:  the biggest storms--the greatest floods, windstorms, snowstorms--when they happen (which is rare), tend to occur in neutral years.  Years that Seattle mayors need to worry about, as should the keepers of the 520 bridge.  Buckle your meteorological seatbelts--its looks like a neutral winter is coming our way.

As many of you know, the signs late last summer were for an El Nino, albeit a modest one.  But after a period of intensification, this El Nino has run out of steam and the current model forecasts (which are more accurate now because we are so close in time) suggest a neutral year.

Here is the latest record of the sea surface temperature anomaly (the difference from normal) for a region in the tropical Pacific (the Nino 3.4 area shown in the map below).   The official definition of a neutral year is when the anomaly is within .5C of normal.   Currently is it about .3C warm.  And the real El Nino effects aren't significant until the anomalies are much larger (at least 1C warmer or cooler than normal).   You notice that the warm anomaly increased significantly in June-early September and then plummeted.

Unusual sea surface temperatures cause changes in the atmospheric circulation and particularly the trade winds (the easterly tropical trades weaken during El Nino years).  Right now they are near normal.  What about the warmth of the upper portion of the oceans?   As shown here, it has dropped recently.

So what about our fancy computer models?   Well, the National Weather Service key tool is its coupled ocean atmosphere global model (CFS 2) ensemble.   Here is the output.  Predicting neutral conditions and no El Nino (temperature anomalies of the Pacific ocean 3.4 area are small).

And there are a variety of U.S. and international models that indicate either a weak El Nino or neutral conditions:

Folks...the cards are stack AGAINST our friend El Nino, with wily gamblers going for that wild kid, El Neutral (or La Nada).

So I told you earlier that although it is no sure thing, the biggest of the biggest storms of all kinds like neutral years.  Here is an example for windstorms (this is from a figure in my Northwest Weather book.  The red squares indicate a major windstorm year (like the 1962 Columbus Day Storm or the 1993 Inauguration Day Storm).  All of them are associated with temperature anomalies in the tropical Pacific between plus or minus one.  This year will be in that range!

I could show you a similar figure for floods or snowstorms, but that would only scare you.  And bring chills to the spine of Seattle mayors past and present.  Importantly, it is ok to get that season lift ticket pass for Stevens, Snoqualmie, or Crystal.

We might well escape a big storm, but in light of the above information it would pay to be ready.  Flashlights, extra supplies, etc.  I would have recommended getting a Subaru Outback (and was thinking of getting one myself), but they have run a series of insulting advertisements about weathermen. 

P.S.  I would like to thank those that contributed to my fund recently (upper right column or here).  I used the funds to pay for the room charges of the recent Columbus Day Storm gathering in Kane Hall and purchase a replacement disk server for our real-time weather predictions.  I also hope to give another undergraduate scholarship this year.


  1. Oh, I hope you are correct! Wasn't 08-09 a neutral winter? Lots of snow in Hazel Dell, WA that year. Loved it.
    One of our local weather dudes, Rod Hill, says it will be mild. I wonder when he will change his tune?

  2. Let it snow, let it snow, let it snow!

  3. The CPC is still hedging towrds a much drier winter. They've been very consistant for months about it. I think theyre stubborn about an El Nino but maybe they know of other factors? They did backoff on the warming though.

    Snowflakes below 2000 ft today near Yakima. It was sticking at 2000ft. Rained all morning, changed to snow the last couple hrs at 2pm. It was a very interesting process because it was the afternoon and no cold air was present. Had to be an example of dynamical cooling.

  4. Yessssss!!!!! Love, love, love stormy weather! Bring it on!

  5. Weather.com experts still saying much colder this winter in the PNW becuase of the Aleutian Ridge.


  6. I have always loved weather, but known very little about how it worked.
    I love your blog. I've been reading it daily for several months now and find it to be incredibly informative.
    Thank you.

  7. "our friend El Nino"? As a powder skier, El Nino is very much my enemy. Die you hideous monster! I say RIP and don't return. I'm rooting for the cool phase of the PDO to dominate our weather. Any thoughts on that?

  8. You may think this is crazy, but I got my first inkling for a stormy winter from my dogs. They have grown in the thickest winter coats they have ever had.

  9. Cliff, can you comment on NOAA's prediction (from October 19th)of the northwest having a cooler and drier winter and how that would effect or relate to the idea of neutral winters being stormier?


    Is your blog post and NOAA's report slightly conflicting each other? I'm trying to understand the reasoning behind both predictions and how they overlap.

    Thank you!

  10. Cliff, I'm really curious how neutral winters affect the Kittitas Valley, specifically Ellensburg. We bought property there and are building (also live there) and commute into Seattle. Just curious what to expect?!?

  11. I heard a remark this morning about our having a "Pineapple Express" winter. Now, I'm really confused.

  12. Interesting post as always Cliff! Thanks!

    Our last big storm here on Vancouver Island were the events of November (9th I believe?), early December 2006 and January 2007. One-two-three punch that didn't it every area every time on the Lower Mainland of BC but did major damage in every case.

    Looking at the ENSO table here:

    2006 and 2012 are nearly identical though if the ENSO forecasts hold, they should diverge as 2006 went into a mild El Nino where 2012 is heading back down towards neutral.

  13. Oh but I want to see graphs of the snowstorms on neutral years.

  14. 'A bit off topic, but today's contrast between the LGX data and the ATX data is greater than the images in a recent post on how "blind" ATX is to big time weather on our coast. I will take it upon myself to see to it that Maria Cantwell sees the images being served up at 8:15 this morning, Oct. 24th. What a great difference! And thanks again to Cliff for his part in making this happen.

  15. Another question on Kittitas Valley Cliff....are we in a fuzzy radar area? It's been snowing in Ellensburg pretty good for a few hours and was snowing really good in Taneum curves as well since around 7am, yet radar looks like there is no precipitation in the area, only to the east of us. I've only been able to keep up by spotter reports from my kiddos and watching the wsdot cams. Manashtash Ridge seems like it is getting hammered...much worse there than in Snoqualmie Pass today and yesterday.

  16. Oh no...please no. Sitting in the dark with no heat for 3 days after last winter's snow and ice storm...please no. Rain..fine with me. But the wind and snow...please please nooooo!


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