February 18, 2019

The Hills Will Be White, But Lowland Snow Lovers Will Be Disappointed

Nothing is more frustrating and difficult for local meteorologists than marginal snow events.  By that I mean marginal temperatures for snow to reach sea level.

Unfortunately, the Washington lowlands are often in this marginal temperature regime and will be so for the rest of this week.  In these situations, the upper reaches of our local hills (above say 400 ft) can have (wet) snow, while rain or a wintry mix hit near sea level.   Being near the (relatively) warm water of Puget Sound, Lake Washington, and the Strait is also a problem.

The picture below shows a typical example of this meteorological frustration, looking northward from the UW towards Capitol Hill. All white at the top.  No snow at the bottom.

During this period, it is critical to know the difference between freezing level and snow level.  Freezing level is the first elevation above the surface where the temperature drops below freezing.  Precipitation generally starts as snow aloft and then falls through the freezing level, beneath which it starts to melt.  It takes about 1000 ft for the snow to completely melt, and we call that level the snow level.  You are now experts in this snow level business.

During the last snow situation, we had the right configuration to bring the freezing level to the surface, often with a low center over SW Washington drawing frigid air through the Fraser River Gap, into NW Washington, and then down into the rest of western WA.

But this week we don't and there is onshore flow at low levels. Flow off the 50F Pacific Ocean.  At 10 AM this morning, the freezing level at Sea-Tac Airport was at 1333 ft, with a snow level around 350 ft.   If it were precipitating now, the top of our hills could be white, while downtown Seattle would be in a cold rain. Yuk.  Enough to make Amazon folks reconsider Long Island City.

Tomorrow, a wet Pacific weather system will move in from the northwest, but as shown by the surface chart for 1 PM Tuesday (colors show temperature at around 2500 ft, solid lines are pressure), the air is not that cold in BC, northwest flow is moving into the NW, and the temperatures are marginal (white to light green).  Wet rain near sea level, wet snow above 500-1000 ft.

This kind of flow can really dump snow in the mountains, since westerly flow has a large upslope wind component up the north-south oriented Cascades. To illustrate this, here is the accumulated snowfall through 4 PM Wednesday from the UW WRF model.   The Cascades above roughly 3000 ft get a foot or more, with lighter snow extending to around 1000 ft, and maybe a bit lower where precipitation is a greater.  But no snow days in Seattle.

The high-tech, high-resolution, 15 member UW ensemble system confirms this snow forecast for Sea-Tac (see below)--so we are pretty sure about this forecast.

And the vaunted European Center model has the same idea.  Great for skiers, bad for kids who don't want to go to school.

But don't give up on snow yet.  There is a much more threatening prediction for Saturday (see sea level pressure and temperature forecast below), with colder air over BC and a low center in the SW Washington sweet spot. 

But let's wait before getting excited about it and keep in mind that there is an increasing problem for low-level snow lovers:  the sun is rapidly getting stronger and days are getting longer.  We only have a week or two left in the lowland snow season before the sun makes serious snow impossible.

A sign of the upcoming warming is found at Garden stores and nurseries, which are already stocked with seeds, plants, and fertilizers.   They will be doing a great business this spring:  the heavy snow has done massive damages to trees and bushes around the region.


  1. Oh boy .. maybe, maybe not!

    It was getting awfully close to shoot the messenger time!!!

    There is still some snow around in Bow.

  2. I like being an expert in snow level business. It's fun to sort of look over your meteorologist shoulder and take in your analysis. This is especially true when you hit the sweet spot of interesting technical detail combined with a lay person friendly context. For example how it applies to readers' daily lives.

    By the way, I read my favorite high-tech bred blackberry bushes will likely be damaged this summer. Apparently, this is due to the timing of our heavy snow/cold event in their budding preparation process. I believe the damage is only to this year's production.

    It would be interesting for your readers' comments to include how the snow event did or will affect their daily activities.

    Meanwhile, I am enjoying reading your blog and know others are as well. It is noticeable that comments seem to follow the tone and content of your writing. The blog about your positive experiences during the snow certainly brought out reader comments we usually don't see. Some positive feedback was uplifting especially as most of us realize the hard, unjust circumstances many face. I am glad these situations were pointed out as well.

    My perspective is that your readers' comments are increasingly bringing something to the table that contributes interest and value which I appreciate.

  3. Nice blog and interesting tidbit!

  4. i'd be really interested in what you have to say about the issues covered by canadian Paul Beckwith in this video....

    climate disruption's effects on food growing etc is a major concern:

    "Climate Disruption is Ubiquitous. Tropics have expanded by 0.5 degrees in latitude per decade since 1970s. Sahara Desert enlarged 10% since 1910. US 100th Meridian has shifted 140 miles to East since 1980. Tornado Alley moved 500 miles East since 1990. Plant Hardiness Zones in US move North 13 miles per decade. Permafrost Line in Canada moved 80 miles North in last 50 years. Wheat Belt pushed poleward 160 miles per decade, and is rapidly moving out of Australia. Thousands of Northern Hemisphere lakes are losing ice cover. Climate of Cities is shifting up to 500 miles within one generation. Arctic has lost 80% of coldest air in 6 decades."

    sadly, i cant remember how to embed live links so readers will have to copy and paste into a new window to watch this...


  5. @Sharon I live by the Sakuma berry fields and they have lots of blackberries and they may be like yours. They have a long season of blooming and producing and the berries are big. In the past there was a winter where the budding process was impacted and they produced little, if at all, as I recall. Things were fine the next season. It will be interesting to see if that happened here this time .. it will no doubt be well reported locally if so.

  6. I can't remember whether Professor Harold Wirtele (sp?) attempted to teach me the freezing level vs snow level thing at MIT in "Elementary Meteorology" or not. Perhaps that time was used up when we computed that MIT's then old weather radar almost certainly couldn't see Sputnik (we went to the top floor of building 20 anyhow, and sure enough could not see Sputnik).

  7. 16-day mean temp in NW Bellingham: 28F; mean hi: 35F, mean low: 21F; range: 44F - 15F. Average February hi: 48F, low: 33F. -13F anomaly!

  8. Any long-time residents of north Whatcom County know that snow in March is by no means an impossibility ~ unfortunately!

  9. Paul Beckwith being interviewed last year....

    his major concern is arctic sea ice.... and he has concerns about how the models are deficient in projecting future scenarios...

    "Paul speaks with Beyond Crisis in Ottawa on abrupt climate change; the earth's warming creating dramatic loss of sea ice in the Arctic; and the urgent need to act NOW to reduce emissions, cool the Arctic and slow the warming trend. This piece gives a detailed analysis on the risks we face from Arctic warming to the overall climate system.

    "We're an innovative, intelligent species but we're total idiots on the climate change issue."

    "I think we're in trouble NOW... The world will wake up one morning and there'll be no sea ice in the Arctic - the weather will be unrecognizable. Will that wake people up? Do we have to reach that point?"

    Paul is a climate science educator, and part-time Geography professor in climatology, oceanography, and environmental issues at the University of Ottawa."


  10. been an extraordinary winter season...what caused the flip from dec/ jan to lock in feb? mjo perhaps? the long range was way off...now nws is trumpeting ocean/ atmosphere finally coupling to insure their forecast of el nino...hmmmm...1951 had a bunch of snow in march...climate variability has its moments for sure.

  11. I wonder... anyone ever thought of outfitting and of the Seattle skyscrapers with observation capabilities? I guess it would not really work (the building itself would mess with the observations). That said, would be interesting to see temperature data every 10m up the side of the building.

  12. Sahila said...

    "Paul Beckwith being interviewed last year....his major concern is arctic sea ice.... and he has concerns about how the models are deficient in projecting future scenarios"

    Thank you for this link. There are also some good Tedx Talks on this subject as well:


    Another excellent source of information on this topic is NOAA's 2108 update of its annual Arctic report card:


    The report describes the continuing substantial warming of the arctic air and ocean to the highest levels over the last five years since record keeping began in 1900. The rate of warming is twice that of the rest of the planet. This warming is believed to be the Arctic’s largest change in human history. The 12 lowest Arctic sea ice measurements in the satellite record have occurred in the last 12 years.

  13. "Paul [Beckwith] is a climate science educator, and part-time Geography professor in climatology, oceanography, and environmental issues at the University of Ottawa."

    I am sorry to hear that Mr. Beckwith is still purveying his "selective science" to receptive minds.

    Beckwith is a PhD student (since 2011) with zero peer reviewed literature. He is a self-described climate change expert who produces scary videos. He predicted the Arctic would be ice-free in 2013. In 2016 he claimed an "unprecedented" crossing of the equator by the jet stream indicated "climate system mayhem" that required immediate declaration of a "global climate emergency."

    Michael Mann called Beckwith's "sensationalist" claim "wrong." Stefen Rahmstorf called it "utter nonsense."

    Regarding Beckwith's claim of an expanding Sahara, does a 100-year average decrease in rainfall at the north and south boundaries of the Sahara desert prove an impending CO2-induced climatic disaster? Does it not matter that the trend reversed after the mid 1980s, when the Sahel began a steady trend to more rainfall?

    The extent of the Sahara was greater during the last glaciation 18,000 years ago, when so much water was trapped in 2 mile thick ice sheets the surface of the oceans was >400 feet lower than today. During that period tropical forests retreated and there were no glaciers on Kilimanjaro. Does Beckwith ever mention this? Does he tell his followers the Sahara has cyclically greened and desertified as the Earth's obliquity cycled every 41,000 years?

    Thankfully, Beckwith doesn't appear to be teaching anymore, but he's still speaking to a credulous choir.

  14. To those who persist in scaremongering on this blog on a daily basis, tell us what you're doing on a personal level to ameliorate your concerns. I've lived in multi - family housing for my entire adult life after college, lived close enough to work that I could take public transportation, and was recycling since my days in the Boy Scouts when it was considered fairly nutty. If you haven't been practicing what you preach then it's time to stop talking and start taking personal responsibility for your actions. I don't tell people how to live their lives, but if do then get to work.

  15. and for those of us who are willing to stare reality in the face, Jem Bendell has interesting things to say...

    Professor Jem Bendell is author of Deep Adaptation, which summarizes climate science and trends to suggest that humanity faces inevitable societal collapse, probably within 10 years.

    Please watch the video all the way through as the mental, emotional and psychological support comes after the 'bad news' is presented and discussed.

    The presentation, to 300 people in Bristol, UK, was his first recorded lecture on Deep Adaptation. Using a more informal format than a University lecture Bendell, who is Professor of Sustainability Leadership at the University of Cumbria, invites the audience to explore forms of action additional to cutting and drawing down carbon from the atmosphere - actions associated with personal and collective preparedness for coming disruption. Accompanying him was Toni Spencer, a facilitator who works on Deep Adaptation and Transition.

    After Jem's talk, Toni led the audience in a reflective process to explore feelings and ideas emerging. She also offered some poems and reflections during the process. Members of the Climate Psychology Alliance spoke from the floor, explaining their new initiative to provide therapeutic support to people working on or affected by this agenda.


  16. So let me get this straight. For the last 5+ years in this comment section (from Nov-Mar) the common theme has been that Seattle does not get major snow events anymore due to AGW.

    Now we have one and... it's blamed on AGW.

    It has been refreshing to see the positive posts and new comments here that don't say a word about it, just are enjoying the moment or sharing a story. Can we maybe give the AGW stuff a rest until Cliff does a post on it?

  17. Regarding Mr. Beckwith: Attention is a powerful motivator. The urge to be heard and to be seen and to be admired is a powerful force that easily turns the good judgment of otherwise intelligent people, Paul Krugman being a fine example.

  18. Picture should read, "looking south from the UW toward Capital Hill".

  19. Paul Beckwith has been caught numerous times claiming things of no substantive merit, only the excitable imaginations of his own not particularly expert mind


  20. Shed A Light: Rupert Read – This civilisation is finished: so what is to be done?

    The Paris Agreement explicitly commits us to use non-existent, utterly reckless, unaffordable and ineffective 'Negative Emissions Technologies' which will almost certainly fail to be realised. Barring a multifaceted miracle, within a generation, we will be facing an exponentially rising tide of climate disasters that will bring this civilization down. We, therefore, need to engage with climate realism. This means an epic struggle to mitigate and adapt, an epic struggle to take on the climate-criminals and, notably, to start planning seriously for civilizational collapse.

    Dr Rupert Read is a Reader in Philosophy at the University of East Anglia. Rupert is a specialist in Wittgenstein, environmental philosophy, critiques of Rawlsian liberalism, and philosophy of film. His research in environmental ethics and economics has included publications on problems of ‘natural capital’ valuations of nature, as well as pioneering work on the Precautionary Principle. Recently, his work was cited by the Supreme Court of the Philippines in their landmark decision to ban the cultivation of GM aubergine. Rupert is also chair of the UK-based post-growth think tank, Green House

  21. Sahilia - Ye gads! If you think humanity is incapable of mitigation, what makes you think adaptation is the holy grail?

    Incidentally, this is the foundational attitude of right wing politics: Forget about climate change mitigation, we will adapt. What they conveniently never articulate is that if zero mitigation occurs, climate change will eventually result in ecological instability. The "change" we see right now is not remotely an instability. We can adapt to what is happening now. It won't be adaptable later.

    instability by its very definition is not adaptable. While the "immediate catastrophe" hysteria of Paul Beckwith has exactly no substantive merit (and if it did, it is far too late for action) we do know with decent confidence that the end of the century does have significant risk of ecological instability.

    Another decade or two will tell about this loopy jet stream hypothesis. Relax and let the experts figure it out, which they surely will. What we need to focus on is what we can still mitigate, which is the risk that exists in the last half of the century to those who have no option but to live with our decisions. Then jet stream behaviour will be anybodies guess under conditions of escalating instability.


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

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