December 26, 2015

The Pacific Northwest: Snow Capital of the U.S.

The U.S. snow depth analysis shows a dramatic picture this morning:  huge amounts of snow over the Northwest U.S., but virtually nothing over the Northeast U.S. (see below).  Washington State has greater depths than any other state (mainly in the Cascades), with amounts exceeded only by British Columbia, the Saudi Arabia of water resources.  British Columbia snow is a big positive for us, of course, since the Columbia drains southward and many of us head to Whistler or other south BC ski areas.

Serious folks in the snow business like to look at snow water equivalent (SWE) instead of snow depth.  SWE tells us the liquid water equivalent (the depth of water if the snowpack was melted) of the frozen water in the snowpack and is a better measure of the water availability when the snowpack melts during the spring.  The SWE for this AM (see below) shows massive amounts in our area, with substantial SWE in the northern and central Rockies.  Bad news over the eastern U.S., where preternatural warmth--reaching the lower 70s was enjoyed during Christmas Eve and Christmas Day.

The temperatures back east were simply startling and opposite of the severe cold they experienced the  last two winters.  Take a look at the max temperatures on Christmas Eve Day.   72F in New York City and Albany.   69F in Boston.

Eastern U.S temperatures have been much warmer than normal all fall.   Here is the anomaly (difference from normal) of max temperature for the past 90 days.  Western WA has actually been a bit below normal.

Why?   The proximate reason is unusually persistent high pressure over the eastern U.S..  Here is the anomaly (in tens of meters)  of the heights at a mid-level of the atmosphere (500hPa) for the past 90 days. . Red means higher heights (pressure) than normal.  High heights are associated with warmer temperatures below.

This is probably the result of natural variability, no reason to expect it is connected with global warming.  What about El Nino?   Probably not at this point.   We have yet to see the normal El Nino circulation changes, which generally are most profound after January 1st and certainly our recent weather in the Northwest is not El Nino-like.  

Finally, some folks in the lowlands may enjoy some snow tomorrow:  those on the Kitsap and SE of the Olympics.  Here is the 24 snowfall ending 4 AM Monday.   Some snow extending over the the Hood Canal area and over parts of Kitsap.  Light snow in the Cascades (few inches).  None over Seattle, so our mayor can relax.

Most of the Kitsap snow will fall tomorrow morning as a modest front crosses our region.


  1. Cliff, is it true that it appears we're heading toward a drier period in Western WA?

  2. Part of this brief counter El Nino feel was due to the active MJO activity in octants 4 and 5.

    This area more commonly sees tropical forcing whilst in La Nina (or La Nada years). Perhaps a coincidence as up-welling kelvin wave in the central equatorial Pacific was observed recently which also seem to assist in cooling of SSTs...and mildly correlate with PACNW winter weather.

    Now it appears a more El Nino tropical forcing state is set to resume for the next few weeks at minimum. Glad we were able to get that snowy period before the cold and dry doldrums set in for January...until we get a more favorable spot in the MJO...which could take until February to be honest.

    Thankfully many dynamical models are showing ENSO neutral to negative beginning summer 2016 - because El Nino can sometimes be 'El Boring-o' for mid and late winter thru spring for weather (and snow) enthusiasts around our neck of the woods.

  3. "British Columbia, the Saudi Arabia of water resources"

    LOL, never heard it put that way..... so true.

  4. Cliff, I'm ready for my snow. The GFS has been fairly consistent overall with the Hood Canal snow so I'm fairly confident. Asked the weather service yesterday and they said it would be too warm- today they have changed their tune a bit.
    Snowed two inches on Monday and they said it would just be rain then as well..

  5. Because the Northeast had such a cold and snowy winter last year people forget that most recent years have had very warm temperatures right up into January, even if not 70s on Christmas Day. My point is that it isn't just a one year aberration, it has been unusually warm in the late fall and winter in the NE for many of the last 20 years.

    We left the NE for Bellingham in 1998, and the one thing we really missed was cross-country skiing from our door. But the truth is that there has been a radical drop in the number of days one can cross-county ski in upstate NY over the last 20 years.

    I would love to see long-term analysis of late fall and early winter temperatures over the last 50 years in NY and New England. Whether natural variability or climate change, I bet you will find quite a strong trend towards warmer Novembers and Decembers.

  6. Cliff,

    My Range Rover won't start. Is it going to warm above 40 degrees Fahrenheit anytime soon? I need to get it in the Range Rover shop...


  7. The United States is not alone with record rains in Texas and South Carolina. The heavy December rains/snow of western Washington are welcome but other portions of the world from India to Paraguay to England to Texas/Oklahoma are severely flooded.

    Army called in as floods continue to devastate northern England

    The army and emergency services were deployed in towns and cities across the north of England on Sunday to lead recovery efforts as devastating floods continued to bring chaos to thousands of homes and businesses. Three major cities were hit, as well as scores of towns and villages, forcing the evacuation of thousands in what David Cameron described as an unprecedented situation.

    The environment secretary, Liz Truss, admitted that flood defences had been overwhelmed and said they would be reviewed. “Every single river [in Lancashire] was at a record high,” she said, adding that in Yorkshire, some rivers are a metre higher than ever before. “Clearly, in the light of that, we will be reviewing our flood defences.”

    In Sowerby Bridge, West Yorkshire, hundreds of homes and businesses were flooded, with residents piling sodden furniture, Christmas presents and other belongings in the street. A few miles down the valley in Hebden Bridge, residents were coming to terms with their third devastating flood in the past four years.

    Forecasters say another band of heavy rain is likely to sweep in from the west on Wednesday and is likely to hit southern Scotland and parts of northern England.

  8. It's snowing in Burien today! A wintry mix at lest with big flakes.

  9. In response to John Bower: it is true that there have been aberrations of warm winter weather in the Northeast, but NEVER sustained to this length. This year has provided 2 solid months of not simply "mild" weather, but record-breaking warmth.

    I was born and raised in the NE. am a weather enthusiast, and take close note of the weather's aberrations. The closest comparison I can draw is the winter of 2011-2012; that is the only winter that remained mild all the way from November until the end of March. November did feature some days in the 60s and 70s, December was mild, but NOTHING like this year. There were no days that had 70s for highs with 60+ dewpoints; such readings border on needing air conditionin! Jan and Feb were slightly above normal, although March was the month that stunned us all. From the beginning of the month, it was in the upper 70s-lower 80s every day. The cherry blossoms opened around mid-March and had fallen well before the month was out, making the festival a non-event.

    I remember taking my niece to see the new MLK memorial in mid-March; we were dressed in summer clothes and even after dark it was sufficiently warm.

    March of 2012 is on a par with what they are experiencing now, but March was only one month. This is two months, uninterrupted. My father told me today that Boston has yet to see its first snowflake this year.

    My question is, are we in Seattle going to break out of this very cold, wet pattern at all? It has been struggling to teach 40 every day and the rain has been nearly incessant.

    Let me make this clear: I am not wishing get for 50s and 60s to melt everyone's much-deserved snow. Just a return to mid to upper 40s; you all have to admit, it's pretty miserable put yhete, even by Seattle standards! Is there any break in sight? Even in the mid 40s?

    What is unbelievable is how dead wrong all those El NiƱo forecasters were. They stated repeatedly and with certainty that we were going to have a warm, dry winter, "aggravating the drought". The exact opposite happened. How could everyone have been so inaccurate?

  10. tracksdc89 - I hear what your are saying about the NE but as far as El Nino is concerned - it is a winter pattern for us - winter just started a week ago so stay tuned - from one who has 50 years of watching El Nino unfold in the PNW.

  11. We got some "Hood Canal effect" spillover on Bainbridge Island yesterday. Several hours of wet snow, melting as it hit the ground where I am (100 feet elevation) but whitening the grass a little bit higher up.

  12. Spending the last few days here in Leavenworth and by far the most snow I have seen here at this same time in several years at least. The snow on the trees and roofs looks more like the snow belts in the Great Lakes! The snow banks are impressive as well. Plain, just North of here had a solid 24" on the ground with even more at Lake Wenatchee. On top of that, we picked up a fluffy 3" yesterday to make for a picture perfect Christmas vacation.

  13. tracksdc89, as a native Western Washingtonian (lived almost 40 of my 46 years here), I echo Michael DeMarco. You're making proclamations about a winter that just started. Also can't admit that it's been pretty miserable by our standards. First couple weeks of December were unquestionably wetter than normal, but those of us who have been here for decades aren't awestruck. Past week or so hasn't been unduly rainy and dry days are forecast. Nothing noteworthy for the time being, and not miserable by any means.

  14. I remember one winter back when I used to drive out to the coast to surf, by way of Lake Crescent. There were huge, ski-resort-sized snow drifts around the middle of the lake. It was back before cell phone cameras existed, and I did not have a film camera with me, but the drifts were at least 10 feet high along the roadside. Does anyone else recall seeing this? I would guess it was the mid to late 1990's. As I recall, we had significant lowland snowfall that year, but I was unprepared for the extent of the snowpack. I believe less than a hundred yards of the road were affected, so it must have been a wind pattern effect. I wonder if anybody on the road crew took photos--most likely it was even worse than when I saw it.

  15. Global Warming induced polar vortex brings warm rain to start washing away snow beginning in approximately two weeks. The south will get our cold, and the blob will begin its resurrection.

    Don't forget this will likely be the warmest year in history, and 2017 will likely be even warmer.


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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