September 08, 2016

La Nina Watch Canceled by NOAA

Today, NOAA's Climate Prediction Center (CPC) announced its cancellation of the La Nina Watch that was in place.  Thus, they expect that we will experience Neutral or La Nada conditions during the upcoming winter.

Now this announcement is not as significant as it might seem, since the forecast La Nina was predicted to be very weak.   As most of you will remember La Nina is associated with cooler than normal water in the central tropical Pacific (the Nino 3.4 area is generally used).  Specifically,  weak La Ninas are associated with a cool temperature anomaly (difference from water) of at least .5C.  Neutral conditions occur when the Nino 3.4 temperatures are within .5C of normal.

Here is the latest forecast for a collection of global models (the NMME ensemble) for sea surface temperature anomalies in that Nino3.4 area.   Temperatures cooled rapidly in Spring and early Summer as last year's El Nino faded.   The forecasts of these models are virtually on the same page--slightly cooler than normal in the neutral temperature range.

The Climate Prediction Center/IRI updated their probabilities of El Nino, Neutral, and La  Nina (see below).    The most probable category is Neutral, followed by La Nina.

So it is probable that we will experience a Neutral-type winter, which has implications for the upcoming weather here in the NW.   Remember there is no certainty here, but rather the atmospheric "dice" are weighted toward the following weather conditions in the Northwest during La Nada years:

1.  Near normal precipitation and temperature.
2.  Greater chance of extreme weather such as heavy precipitation, windstorms, big snowstorms.
      Remember these big events are still rare, but they do have a tendency to occur in Neutral years.

We also might expect normal reservoir conditions going into next summer.

Announcement: Talk on Northwest Climate Surprises on September 28.

During the evening of September 28, I will be giving a talk in Seattle at UW's Kane Hall on Climate Surprise: Unexpected Impacts of Global Warming on the Pacific Northwest. You think global warming will simply bring warmer temperatures, drought, less snow, and more storms? Think again. The latest climate model simulations provide a far more nuanced prediction of what will happen here, with some of the results quite surprising. This talk is sponsored by CarbonWa and the Audubon Society To find out more or to secure tickets, please go here.


  1. Yay! I'm so ready for a crazy fall/winter with big wind storms, lots of cold, and lots of snow. I know this doesn't mean it's a for sure thing we'll get them, but at least there's a slightly better chance! Bring it on!!!

  2. Professor Mass,

    You wrote:

    1. "the atmospheric "dice" are weighted toward the following weather conditions in the Northwest during La Nina years"

    2. "Greater chance of extreme weather such as heavy precipitation, windstorms, big snowstorms. Remember these big events are still rare, but they do have a tendency to occur in Neutral years."

    It's the wording "but they do have a tendency to occur" that has me interested. It sounds as if the tendency (the inclination) is equal to La Nina years? I'm wondering might you expand on the "inclination" please?

  3. Is it possible to have "near normal" weather in the winter without La Nina? If our post-1976 warming is averaging 0.28C/decade (over land), then it seems every winter that wants to be "average" is already fighting against 1C.

  4. The PDO, which has a more direct impact on Northwest weather, is now negative, and has been cooling every month.

    1. There is a common misconception that the PDO actually controls atmospheric patterns. This is not the case, and is in fact, the other way around.


      Also, we're not quite into the 're-emergence period' where the previous spring's SST anomalies rise back up (which is caused by the stirring up of the North Pacific as the polar jet moves southwards in October and November).

      I can't find the original paper on this, but this blog post covers it pretty well.

      Bottom line, changes to the PDO during the summer often disappear by November, and the PDO while correlated with weather conditions in the PNW, is actually _caused_ by those conditions, not the other way around.

  5. Thinking about renewing the ski pass. What's the ruling?

  6. Hi Cliff! Very curious about what the Eastern Pacific SSTs are doing in light of you pointing out La Nada is likely. I'm sure you've seen some of Bob Tisdale's blog at some point in the climate blogosphere - he seems to think The Blob might be coming back based on SSTs in the (40N-50N, 150W-130W) region-

    What's your thought there - is his analysis flawed or missing something? Since it looks like La Nada on the way, it seems like we could expect a pretty boring average winter. But we all know what the Blob means (and I'm a skier so I hate it).

  7. Wasn't that a typo on "the atomospheric "dice" are weighted toward the following weather conditons in the Northwest during La Nina years..."?
    Shouldn't that read "La Nada" years since you said earlier that the La Nina watch was cancelled so we would be Neutral or in La Nada this coming winter?
    Just asking for clarification of your statement. Thank you.

  8. For those of us who get crossed eyed figuring out El Nino, La Nina, and La Nada perhaps a bit of coding would help at least for the NW:
    El Nino (H/D) = hotter drier
    La Nina (C/W) = cooler/wetter
    La Nada (N) = normal (i.e. same old same old)

    David E. Ortman, Seattle, WA

    1. Wait, wait--"same old same old" also means some great windstorm with power outages and possible snow in the puget sound Lowlands. More exciting than it sounds, I'd say!

  9. CLIFF,

    Noon; Looking west over Blake Island I see a cloud that is circular, yes perfectly circular, no other letters or numerals present thus I rule out that it is man made.

    Whats up Dpc??

  10. Dr. Mass, I have heard talk that the "Blob" is back. I see that there is a large pool of warm water, but it looks a bit further west than the one we had a couple of years ago, and I also see the PDO index is dropping toward neutral. I would like to know your thoughts.

  11. I am now interested to see how this winter plays out! 2008/1979 would be great, but I'll take what I can get!

  12. Robert Lewis -

    Without seeing a photo or drawing of what you describe, I would make a guess that what you saw was perhaps an aircraft contrail, most likely a military refueling tanker orbiting over the Olympics. I have seen this now and then, usually part of a training exercise for jets out of NAS Whidbey Island. Also possibly a Boeing flight test.

    Assuming you mean a circlular outline vs. a 'solid' disc - the latter could be a lenticular cloud caused by the Olympic mountains.

  13. Haven't got the reference handy, but at about the same time the Japan Met organization was declaring La Nina to be in effect.


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