January 13, 2010

El Nino, Snow, and the Olympics

There have been a number of calls today about the influence of the recent warm weather on the snowpack, and many were about the upcoming winter games in British Columbia. Big news today: Cypress Mountain near Vancouver, the future venue for freestyle skiing and snowboarding, was closed to protect its rapidly thinning snowpack. An observing site on the mountain at 3100 ft went from 43 inches of snow on 1 January down to 27 inches today. Not good. But I suspect they will be ok, due to the aggressive snow mining and snow making operations, and the inevitability that there will be some cooler periods when they can build up the snow pack both naturally and artificially. Those Canadians are determined to pull this off and they probably will. And they have a very experienced team of weather forecasters and lots of additional weather gear.

The problem of course is El Nino. As shown in the figure below, the tropical Pacific is much warmer than normal, and the second figure shows the variation of central Pacific surface temperature ( the famous Nino 3.4 zone) is roughly 1.5C above normal. Both of these figures suggest a moderate El Nino right now and this is NOT going to change during the next few months.
As I have explained before El Ninos are associated with above normal temperatures and below normal precip after January 1. And substantially lower than normal spring snowpacks. Now, lets be careful...this is a correlation, not an exact prediction. El Nino winters tend to have less snow, but some have had more than normal. Now the problem we have is that we are starting the El Nino season with a below normal snowpack (see the latest values in graphic below). Lots of the NW is 65-80% of normal. And the latest long-term prediction of the Climate Prediction Center reflects the El Nino correlation (see graphics below). Warmer than normal from Washington to the upper Plains. Wetter and cooler than normal along the southern tier of states.

So let me be blunt: I wouldn't run out and buy a season pass at Snoqualmie Summit right now...but you probably suspected that.

We are in a break right now, but tomorrow (Thursday) strong SW flow will redevelop and heavy rain will again hit the SW sides of the Olympics, the mountains of Vancouver Island, and the N. Cascades. Snow level will rise. Winds will pick up again over NW Washington and along the coast. AGAIN! And the current model runs showing this repeated several times during the next week. The general pattern is pretty locked down, so get used to it.

Here is a marvelous graphic of the integrated moisture content of the atmosphere tomorrow at 4 PM. A narrow plume of moisture headed towards us...a.k.a. an atmospheric river. But more on that some other time.


  1. I'm going to trademark and coin the phrase Santa Clause Express. Its when that moisture plume originates beyond the Hawaiian Islands, but more where Christmas Is. is located.

    PS. Finally the inversion is broken. First chinook westward wind in months. 46 degrees, warmest since early December.

  2. Very interesting column Dr Mass, thanks. Will you be presenting at Sand Point in March?

  3. Seems like SoCAL will finally get in on the el nino express next week. That has been one of the missing ingredients to make us feel secure that we got climate figured out. Except one might argue by looking at the Climate Impacts group historical El Nino maps


    Precipitation in % and soil moisture doesn't match up here in the NW corner as of today. I wonder on the snowpack anomalies for el nino years if the deficient snow water equivalents are due to lack of falling precipitation or when the snow survey is done it has been disintegrated from to much warm precipitation?

  4. Putting the snow (or lack thereof) issues aside for the moment, I note that Cliff says "El Ninos are associated with above normal temperatures and below normal precip after January 1," whereas I had assumed that such conditions would usually happen in El Nino Decembers as well. But we're well above normal this January for precip in any case, so the J-F-M CPC forecast graphic (made nearly a month ago) Cliff shows has NOT (yet) been borne out with respect to the precipitation element for western WA. I don't know -- maybe this beats fog and air stagnation advisories; but I do hope the hose does get turned off soon, or at least aimed in another direction (as perhaps Josh is suggesting) for awhile.

  5. Thought I'd also point out that the CPC forecast ONLY for the month of January (and made two weeks after the 3-month one that Cliff shows) is even more striking in its prediction of above normal temps and below normal precip for western WA. Above normal temps so far? Yes. Below normal precip? No.

    Hey Cliff (or anyone who knows): I note that we seem to be on a 15-day streak of high temps (and lows, for that matter) above that date's average at Seatac. Are we near any consecutive day record for above average maximums for this time of year?

  6. As someone who has sat through countless Powerpoint technical presentations over the years (some --maybe most -- of them real yawners and far too long), I have a great appreciation for a single information graphic that can explain much of the subject in one glance. From that point forward, the reader or listener can then focus on what the writer or presenter has to say to fill in the blanks. Instead of trying to read a list of bullet points or paragraphs of text while the presenter is talking.

    The 'atmospheric river' graphic and the accompanying title is such a strong graphic. They work in tandem - the title puts the subject in terms of a terrific and familiar analogy. One not necessarily obvious if it wasn't mentioned. The graphic tells the rest of the story - what, where, why and when.

    Nice work. Thanks for showing. I like to collect these sorts of examples to think about how to improve my own work.


  7. This is what they are predicting south of us. I'll be down there next week. Oh boy......:

    This is what the emergency response community is saying:

    Currently, the strong El Nino is reaching its peak in the Eastern Pacific,
    and now finally appears to be exerting an influence on our weather. The
    strong jet has been apparent for quite some time out over the open water,
    but the persistent block had prevented it from reaching the coast. Now that
    the block has dissolved completely, a 200+ kt jet is barreling towards us.
    Multiple large and powerful storm systems are expected to slam into CA from
    the west and northwest over the coming two weeks, all riding this extremely
    powerful jet stream directly into the state. The jet will itself provide
    tremendous dynamic lift, in addition to directing numerous disturbances
    right at the state and supplying them with an ample oceanic moisture source.
    The jet will be at quite a low latitude over much of the Pacific, so these
    storms will be quite cold, at least initially. Very heavy rainfall and
    strong to potentially very strong winds will impact the lower elevations
    beginning late Sunday and continuing through at least the following Sunday.
    This will be the case for the entire state, from (and south of) the Mexican
    border all the way up to Oregon. Above 3000-4000 feet, precipitation will be
    all snow, and since temperatures will be unusually cold for a precipitation
    event of this magnitude, a truly prodigious amount of snowfall is likely to
    occur in the mountains, possibly measured in the tens of feet in the Sierra
    after it's all said and done. But there's a big and rather threatening
    caveat to that (discussed below).Individual storm events are going to be
    hard to time for at least few more days, since this jet is just about as
    powerful as they come (on this planet, anyway). Between this Sunday and the
    following Sunday, I expect categorical statewide rainfall totals in excess
    of 3-4 inches. That is likely to be a huge underestimate for most areas.
    Much of NorCal is likely to see 5-10 inches in the lowlands, with 10-20
    inches in orographically-favored areas. Most of SoCal will see 3-6 inches at
    lower elevations, with perhaps triple that amount in favored areas.

    This is where things get even more interesting, though. The models are
    virtually unanimous in "reloading" the powerful jet stream and forming an
    additional persistent kink 2000-3000 miles to our southwest after next
    Sunday. This is a truly ominous pattern, because it implies the potential
    for a strong Pineapple-type connection to develop. Indeed, the 12z GFS now
    shows copious warm rains falling between days 12 and 16 across the entire
    state. Normally, such as scenario out beyond day seven would be dubious at
    best. Since the models are in such truly remarkable agreement, however, and
    because of the extremely high potential impact of such an event, it's worth
    mentioning now. Since there will be a massive volume of freshly-fallen snow
    (even at relatively low elevations between 3000-5000 feet), even a
    moderately warm storm event would cause very serious flooding. This
    situation will have to monitored closely. Even if the tropical connection
    does not develop, expected rains in the coming 7-10 days will likely be
    sufficient to cause flooding in and of themselves (even in spite of dry
    antecedent conditions).

  8. A couple of El Nino questions

    Most of the discussion of El Nino is about winter/spring effects. How long does El Nino last? Are their late spring / summer effects? If so what are they?

    Is there any information on year to year cycles between normal, El Nino and La Nina years? Is there a pattern or cycle?


  9. Not even a mention of climate change? Not saying this event is correlated, but seems odd to ignore the question.

    (I am not making this up: the comment form's word verification is "sking". High blogging comedy.)


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