Thursday, November 21, 2019

The Northwest Will Go Cold Turkey, But What About Snow?

It is now becoming clear that a major cold period will occur next week, cold enough that if you lack enough refrigeration foryou holiday meal, you can simply put the food  outside.


Highs will only rise to the upper 30sF on the western side of Cascades and there will be substantial snow in the mountains.  But will there be lowland snow?  That I will explore later.

The models are now consistent in bringing cold air southward, as illustrated by the WRF model forecasts shown below, which present sea level pressure (solid lines) and temperature about 3000 ft above the surface (color shading).    Next Tuesday at 1 PM, cold air (blue colors) is entering the region, pushed southward by high pressure in Canada and a low pressure area off the northern Oregon coast).


By 10 AM on Wednesday, cold air is entrenched over the Northwest, with a very strong north-south pressure gradient that will create strong northerly and northeasterly winds. 

The cold is "in the bag", based on lnsemble predictions in which the models are run many times.  The forecast temperatures at Sea Tac, based on the European model, indicates highs in he low 50s this weekend (pretty typical), but then the "cold turkey" comes in Wednesday and Thursday.


The cold wave will be initiated by the movement southward of an upper trough (see below for 7 PM Tuesday), but it is too broad and offshore to provide western WA with lowland show--perhaps a few flurries.   There is a bigger risk for Portland


The WRF snow accumulation forecast though 4 AM Thursday shows snow on the slopes of the Cascades, but very little over the Puget Sound lowlands....Portland has a better chance.


I know some of you love lowland snow (or fear it), but November is early for the lowlands.  We need colder air, with an upper level shortwave and its surface reflection that would result in easterly flow over the Cascades, which tends to cause drying over the lowlands.     But the situation is still well out in time and things can change.  Stay tuned.

28 comments:

  1. Some nice YWL-BLI gradients for Fraser River outflow on some of the ECMWF ensemble members. Only a couple wind storm solutions, and like you said, most of them are chilly. Im kind of amazed at how deep some of the ECMWF runs are with the initial low pressure that moves into OR/CA. Interesting track.

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  2. Did anyone look for the Aurora last night? I looked out around 11:30, but didn't see anything. The forecast was somewhat dubious. Cliff, you want to comment?

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  3. i agrre but also disagreee the cold temps will stay low were i live ill get snow i live near granite falls

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  4. I looked for the aurora and didn't see it either but I also looked at the forecast on Space Weather and didn't see anything there that would indicate that it would be visible here. The forecast looked pretty tame.

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  5. The only reason I worry about snow events here is the utter freakout among the populace and road crews. It's been only a few years since the last time there was real snow and ice, but I fear they've learned nothing since then regarding pre and post - treatment of roads and driving behavior.

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    1. It always surprises me that a lot of people in the Northwest spend extra thousands of dollars for super-equipped AWD vehicles but won't invest $100 in a set of chains. Then, they slide all over the place on all-season tires.

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    2. There was a major snow event February, 2019 here...

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    3. Recent news article showed that more than half the population in western washington is from out of state, majority of them from california. It's no wonder so many people don't know how to drive in the rain or snow. Living here my whole life I've gotten very very use to driving in adverse weather. More than half the drivers are from sunny dry areas, meaning the roads are dangerous due to high amounts of unskilled (in this weather) drivers.

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    4. not just that its cali they tires are different and laws too they need to have tires that change shape or snow terrain like a tank i think they have them but they would make so much more money only if they sold them cheap

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    5. I'm from CA, I know my limits and stay off of icy/snowy roads. Wish Employers were more understanding of people who can't drive in those conditions. They don't happen too often, why not tell drivers to not risk lives just to come in to work?

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    6. Even if you are wise enough to not drive in icy/snowy conditions, it does not hurt to have a set of chains in the trunk. There will always be that one time where you have an emergency, or you absolutely have to be somewhere, or you are caught by surprise while traveling. I think some places in Canada and Europe have the requirement to always carry chains between fall and spring.

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  6. the reason i want it to snow is because it gives kids time to be with there parents ha i go to cav and people are freaking out over the extended forcast cliff the forecast looks promising

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  7. Eric Blair it's only been a couple of months since the last major snow event(s) in Western Washington. Remember last February? https://cliffmass.blogspot.com/2019/02/a-major-snowstorm-will-hit-region.html

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    1. FYI - I live in Portland, which was mentioned in Cliff's forecast as possibly being in line for a snow event.

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    2. man i agree with you on that blog> i have no clue if you know were lake roesiger is but i live up near there and while lake stevens got 1 in a half feet i got 4 feet on the ground i'm only up 900 ft above sea level then if you drive down the road about to 600 feet they hd2 feet elevation matters

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    3. youre gonna get 1 inch to bad lol

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  8. It's only been 9 months since our last major snow event, but you are right, nothing has likely been learned. As far as driving behavior, it's not just our region that struggles. The first major snow event of the year in places like Detroit and Minneapolis usually bring headlines about major pileups on the highways.

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  9. Eric, where is "here" for you? We got a major snowstorm in Seattle in February of this year, and we seemed to handle it a bit better than previous "snowmageddons," although it was funny to see the grocery store shelves being stripped bare as if it was the end of the world.

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  10. Snow here is great. It shuts down the incessant tech obsessed maddness and for a day or two we get to enjoy living in simpler times and witness the better side of humanity.

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  11. my dad said 1985 snow storm broke temps in seattle 0 degrees and my dad said if a pocket of air in alaska stays there we could get a lot of the because it will feed us the weather seattle in 1985 got 16.4 inches in 24 hours

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    1. The November '85 storm was one for the books.(I remember it well) But Seattle temps were nowhere near zero, although we did have about a week of subfreezing temps. The 17 or so inches of snow in Seattle was two separate storms days apart, not in 24 hours.

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  12. Whistler/Blackcomb no way is opening when they planned to in a week; 10cm alpine base. Looks like some snow for BC over the weekend, but beyond that it's looking cold and dry for the next two weeks along the south coast and interior. We had more precip in Sept alone then October and Nov combined... same with July. Been drought conditions in southern BC for over a month and a half with no end in site. Jet stream just ain't interested in us.

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    1. Ya you're right. Aside from one wet week in October and last weekend's rain storm it has been incredibly dry. This is clearly another year of the west coast ridge (like Fall/winter 00/01, and Fall 2002, 2005 and 2013). We better get used to it. If climate change means weaker more wobbly jet stream patterns than this is the new normal I think.

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  13. Throw this forecast out the window. We're going dry again for a few weeks.

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  14. Max temp in NW Bellingham today of 44.9F. Coolest daily maximum of the season, so far.

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  15. I'm having flashbacks to the PNW of 2014/2015 where the jet stream would flip flop on a dime between too warm and moist with high freezing levels. The snow pack is in similar shape currently if not worse near the coast. There were statements saying that the blob was dissipating but looking at this paints a very different story.

    https://weather.gc.ca/data/saisons/images/2019112300_054_G6_global_I_SEASON_tm@lg@sd_000.png

    14 day forecast shows snow today/tonight then nothing but cold and dry. If a more seasonal pattern doesn't establish into the 2nd week of Dec the holidays are going to be looking very dire. I anticipate whistler blackcomb opening will be delayed by at least 2 weeks.

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  16. In reference to where the residents of Washington were born: cannot narrow it to just western Washington but here are the 2017 numbers for the entire state. I am listing just the top 6 states:
    Washington: 6,962,450
    California 1,240,138
    Oregon 562,468
    Texas 230, 068
    New York 211,366 (Including one Cliff Mass--Welcome to Washington!)
    Illinois 208, 196
    Here is my source: http://depts.washington.edu/moving1/Washington.shtml

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  17. Seems like it going to be real easy to write this rainy season off already but perhaps the transition from "winter" to spring might be more eventful, similar to last year. Although last year if memory serves started off promising, it then proceeded to fall flat on its face for most of December/January (ridge) only to go on a weather rampage in Feb/March.

    Or the region could just have the same never ending ridge carry through all of winter, spring and roll right into summer. Track from due west to east means weak systems that mostly get blocked by mountains. Indeed throw the forecast out the window, and the odds. Hopefully what rain we get is quality over quantity in that it doesn't just run off.

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