January 04, 2024

Major Mountain Snowfall Guaranteed PLUS the Potential for Lowland Snow

We are now close enough in time to be quite certain that the Pacific Northwest mountains will receive a major snow dump.

We also know that the first half of January will NOT be characterized by El Nino warmth, as had December.

And it is now clear that there is a possibility for snowflakes reaching sea level in some parts of western Washington.

So let's get to the details.....

The latest high-resolution UW forecast for total snow accumulation over the next 4 days (96-h, through 4 AM Monday) predicts 1-2 feet in the central and northern Washington Cascades and the mountains of southwest British Columbia.   Very consistent with previous forecasts.  

The freezing level is relatively high this morning (about 5000-4500 ft) and will decline to around 2000 ft this weekend.

The snow will arrive in two events, both associated with incoming Pacific fronts.  One today and the other Saturday.

A nice start for local skiers....but not enough!

It will be the second act on Tuesday and Wednesday that will really put a smile on the faces of snow lovers.

A strong upper trough/low will move into our region which will be the key feature (see the 500-hPa, roughly 18,000 ft map at 1 PM Tuesday below).


This upper level is associated with a surface low (see level pressure forecast for Tuesday morning below, as well as low-level temperatures), with the track of the low bringing it across the north-central WA coast.   Also, note the cool air (blue and purple) in the interior.


The location of the surface low is critical.  If it moved 100 miles to the south, western Washington could be snow-bound.   And this low has been moving around in recent model runs.  Thus, there is uncertainty.

The result of the approaching low/trough on Tuesday will be substantial additional snowfall in the mountains.

To see this, first look at the accumulated snow over Washington through 4 AM Monday (the closer version of what I provided above).


Compare that to the accumulated snowfall through 4 PM Thursday.  A LOT more.  More than 3 feet of new snow in the mountains in total starting today.


Not much lowland snow except for one location... in Whatcom County northeast of Bellingham. 

This area will be cold enough for snow-- from outflow through the Fraser River Valley.

To show you this, here is the wind speed forecast for 4 AM Wednesday.  You can see the strong, cold northeasterly flow hitting those poor folks in Whatcom County and on Orcas Island!


A close-up shows the Fraser River winds clearly.


There may be some occasional snowflakes mixed in to rain over the rest of the lowlands, but nothing of note IF THE ABOVE FORECAST IS CORRECT.

This far out there is still considerable uncertainty, so stay tuned.  

The European Center model is generally in agreement with the above, but does place a band of substantial convergence-zone snow over the north Sound on Thursday/early Friday.

24-h snowfall ending 4 AM Friday.



14 comments:

  1. Cliff, do you have any idea why that European model would put 9 inches in Ellensburg, while there is less than an inch to the north and south in Wenatchee and Yakima? This doesn't seem realistic to me, unless it was a snow-level issue, with both places being lower elevation than Ellensburg. But I believe there is supposed to be enough cold air in place to where that would not be a factor?

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    1. You can get features such as a cross cascades convergence zone or something based on interactions with local terrain. Would not put a lot of credence in it at such a long projection...cliff

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  2. Cliff. The KIRO weatherman on noon broadcast said some of the models had backed off on the cold and possibility of snow for Seattle. What are you seeing in the latest models.

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  3. Cliff where do you find these models especially the last one? I live north seattle and it shows 4-5 inches???? Also I hear vancovvver gonnag et lots of snow portland has a chance no one is talking about seattle if that model shows 1-2 inches lowland

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    1. Not cliff but these are good ones for models weather.us and tropicaltidbits.com

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    2. Weather.us & tropicaltidbits.com

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  4. This comment has been removed by the author.

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  5. Appreciate the detailed update, Cliff ..

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  6. The evolution of the (Weather Channel/Weather Underground) forecast over the past several days has been fun to watch and clearly indicates the uncertainty in how cold/how much snow we can expect next week - great fun for those with patience and a love of weather! At this point, it appears likely that we'll see the coldest temperatures at my location in Bellingham since February 2023 and possibly since December 2022.

    Whatcom County is most certainly the ideal location in the interior lowlands of Western Washington for those who enjoy true winter weather.

    While the forecast has been indicating the potential for substantial snowfall around these parts, having lived here for many years, I'm always fairly skeptical when it comes to snow as Fraser Outflow, while cold, is also bone-dry. This tends to limit accumulation here and increase it on the north side of the Olympic Peninsula due to orographic precipitation enhancement as those northeasterly winds are forced to rise along the Olympic Mountains.

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  7. Looking at today's Windy.com forecasts, it's going to get COLD at the end of next week. Possibly below zero Fahrenheit in the Puget Sound, and -34°F in Darrington (ECMWF model).
    This will be interesting to follow.

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    1. This is a stone cold classic example of why any given model prediction does not a forecast make.

      Cold temperatures of such extreme magnitude are all but climatologically impossible (though never say never, as we all remember June 2021) for this area. For example, Darrington has readily available weather records dating back to 1911 and during its 113-year period of record the coldest temperature ever measured was -11F on 1/11/1916. The probability that Darrington will break its all-time minimum temperature record next week(end) by an enormous 23F margin is vanishingly close to zero. In fact, such temperatures are almost certainly only possible, in Western Washington, high on the volcanoes as even Paradise, in Mount Rainier National Park at 5400', has an all-time record minimum temperature of -20F on 12/9/1932.

      If the Euro is calling for -34F at Darrington it must think Winthrop will break the minimum temperature record for the lower 48.

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    2. Near no chance darrington gets to -34, but it's been fun model riding the past couple days

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  8. If it got below zero in the Puget Sound area, you'd have lots of dead people, with the homeless population being what it is. To me, there's nothing interesting about that, that would just be a disaster. Good thing that is a ludicrous forecast that is not going to happen. -34 in Darrington is laughable.

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  9. The Low over the edge of the Baring Sea, near Unalaska, has been stuck there for several days. That's 2,000 miles from WA. Maybe it will just fill in, and go away. Watchful waiting.

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