December 20, 2023

What is the snow forecast for the holiday season?

 I have gotten several emails from readers asking about the snow situation.

What are the chances for a white Christmas in the lowlands?    What about more snow for the mountains and ski areas?

I will do my best to answer these questions in this blog.

What is the snow situation right now?

The short answer is that current snow coverage and depth are below normal, with barely enough to run the regional ski facilities in Washington.

Let's begin with the latest USDA Snotel maps (below).  Most of the mountainous areas are 55-65% of normal, with the Olympics (29%) being a low outlier (due to a warm, atmospheric river a week ago).


To get a total view of the regional snowpack, consider the latest snow depth graphic from the National Snow and Ice Center.  Nothing over the lowlands (no surprise) and only modest amounts in the mountains.  Oregon is not in good shape regarding snow.

A year ago, when La Nina was in place, there was a lot more snow, which extended down to lower elevations.  

Looking to Christmas Day and beyond
 
Over the next 96 hr (through 4 AM Sunday), there will be only modest snow in the mountains, as suggested by the high-resolution UW modeling system (see below).   Enough to make up for melt and sublimation, but now enough to meaningfully improve the situation.  The European Center forecast forecast is similar.


Then it dries out for a while.   So no white Christmas for western Washington and Oregon.

But the mountains have a chance for more significant snowfall later next week.  An upper-level trough will approach our coast on Wednesday, as shown by the 500-hPa map (about 18,000 ft) on Wednesday (below).


This feature will bring significant snowfall to the mountains.  To illustrate, the map below shows the accumulated snowfall through 10 AM Thursday.   British Columbia gets many feet from this event (great for Whistler) and Mt. Baker will get a significant snow dump.   Not much for Oregon.


Finally, any good forecast should provide the uncertainty of the prediction. Here is the snow predicted at Stampede Pass from the NOAA/NWS GEFS ensemble system of many forecasts.  All the models agree on some light snow before Christmas, but there is a lot of uncertainty regarding the major snow event next week.   Be warned!   Will have to keep an eye on this forecast.








11 comments:

  1. Any sign in the longer-range model predictions that the Western Washington lowlands will see any wintry conditions (Fraser outflow?)/that this persistent ridging will break down or (preferably) retrograde, allowing for the possibility of an intrusion of arctic air? The weather this month has been achingly boring especially compared with the past couple of Decembers.

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    1. Because the last couple of December's were ruled by la Nina. This one a very strong la nino.is in place and is beginning to take effect. Warmer drier winter .less chance of snow and arctic air making a visit. Not zero just lower than you'd see in the opposite .

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  2. As most of us know, the Yakima and Kittitas valley irrigators rely upon mountain snow melt for their crops. What is the prognosis for adequate irrigation water for summer of 2024?

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  3. and right on cue, the local MSM here in Portland has already begun the wringing of hands regarding the low snowpack levels here near the end of the year. They rarely mention the effect of what is now widely considered to be a strong El Nino winter, they'd much rather focus on AGW, as always. You can tell that their days are truly numbered, since so many are calling for the government to step in and save their collective hides. No self - reflection on why they're in such dire straits, no introspection on ways to improve and thus restore the public's trust.

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  4. I'm expecting a early spring this this year thanks to El Nino, I'll be getting my garden ready by the end of February at the latest.

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    1. My garden thinks it's spring already - snowdrops and monkshood sprouting, iceland poppies still blooming, foxgloves huge and looking ready to bloom at the drop of a hat.

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  5. BPA has shown almost Zero wind power for a week. Next Wednesday might change this.

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    1. John, what we have seen this past week is fairly typical for December and January. Many days are well below ten percent of total wind/solar nameplate capacity with a few short periods here and there of 30-40% of total nameplate. In the meantime, Columbia Generating Station chugs along at a steady 1,100 MW output all day, every day. I'll post an enlarged version of the BPA's 5-minute load balance graphic for the period December 14th -- December 20th before today is out.

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    2. The Biden Administration has now signed an agreement with the Indian Tribes and with several environmental groups to begin the planning work needed for removal of four dams on the lower Snake River in Washington state.

      The proposed replacement for the power now being produced by these four dams, which together have a total of approximately 3,000 MW of real-time generation capacity, is a combination of wind, solar, and energy conservation.

      The four dams generate a total of 9.8 Terawatt-hours of electricity annually. For comparison, the 1,100 MW Columbia Generating Station in Richland produces 8.5 Terawatt-hours annually.

      In theory, a combination of wind and solar backed by grid-scale batteries could replace the 9.8 Terawatt-hours generated from the four Snake River dams. (In theory.)

      But there is this big problem, as is demonstrated in this snapshot graphic adapted from the BPA technical operations group 5-minute real-time energy generation report:

      BPA Load and Generation: 14 December 2023 - 20 December 2023

      Currently installed wind and solar nameplate capacity within the scope of BPA's load balancing authority is approximately 2,800 MW -- about as much nameplate capacity as the total of the four Snake River dams, roughly 3,000 MW.

      A normally-accepted capacity factor for wind & solar is 35% of nameplate or less. If you have 3,000 MW of wind & solar nameplate on the books, your actual capacity over a period of a year's time is roughly 1,000 MW equivalent, or less. (Most of the time, it is less.)

      Looking at the graphic, less than five percent of the BPA's installed wind & solar nameplate capacity was available during the period of 12/14/2023 through 12/20/2023, simply because the wind wasn't blowing and the sun wasn't shining -- as is typical of the winter months in our region.

      Some days are higher of course, but the fraction of nameplate usually runs at about 7% during December and January. Far less than the 35% optimum capacity factor when the wind is blowing hard in the spring and fall and when the sun is shining bright overhead.

      What this means is that if wind & solar are to fully replace the lost capacity of the four Snake River dams during the winter months, then somewhere between 6,000 MW and 9,000 MW of new wind & solar capacity must be installed, the actual total depending upon how much grid-scale storage battery capacity is being included.

      If the four dams are breached, getting that much new wind & solar constructed in the time frame which must be covered is next to impossible. The only practical means for dealing with the power generation shortfall is to impose a series of strictly-enforced energy conservation measures on all of BPA's power consuming customers.

      And to do so at a time when America's reliance on electricity will be growing at a rapid pace.

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  6. Currently in BC it's shaping up to be worse than 2014/2015 . I was at Whitewater that year and it was rough start that never got better. That being said, Red Mountain had opened by now that year. This year they have yet to open. A few mountains on the coast have either shut down or have yet to open. I've been living in Revelstoke for 8 years and for late December this is by far the least amount of snow I've seen in town or on the mountain. From my understanding El Nino vs La Nina vs neutral, the impacts are not as big as the hype; even in the last strong El Nino year 2015-2016. This year Nov/Dec have been much drier and much warmer. Is there an additional factor at play?

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  7. The weak frontal system passing by today just pulled in the driest air at my location in Bellingham since 11/24. The relative humidity fell, briefly, to 65%.

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