Fresh Mountain Snow and a Very Dry December Start

10pm Thursday

Today was a gray day but only around .10″ fell in much of the metro area…a classic “soggy” but not “soaking” Pacific Northwest day.  The month ends in just two hours;  it was a slightly wetter than average November in Portland.

Mark November Rain

The first day of December (tomorrow) looks dry as we wait for a weakening cold front to move inland during the evening.  Another chance to hang your Christmas lights and stay dry.   For you skiers/snowboarders this is the plan for tomorrow and the weekend:

Snow Report2

There is only one wet day in our 7 Day Forecast this evening and that would be Saturday.  That’s because next week a new weather pattern takes hold.  It’s a pattern we never saw last winter;  a big “blocking” ridge of high pressure parked over the west coast of North America for many days, possibly well beyond a week.  For comparison, the last time we saw 7 consecutive dry days in December was 4 years ago.  Back in December 2011 we went 9 consecutive days without rain so it’s a rare event but it DOES happen.  Take a look at the upper-level map (500 millibars) for Tuesday.


You see the big ridge developing along the West Coast and a very cold trough pushing cold air down over the Great Lakes.  Next week I’m sure the national weather story will be winter arriving in the eastern half of the country.

In this pattern we’ll see surface high pressure set up east of the Cascades.  That will push a strong easterly wind through the Columbia River Gorge.  Tuesday is the beginning of that setup and it’s possible that east wind will continue for at least week!  In December an east wind is cold as the valleys cool off and stay chilly under wintertime inversions.  The Cascades will turn quite warm next week, likely well into the 40s or even 50s at the ski resorts.  But blue sky and clear/cold nights will keep snow melt to a minimum.

That upper-level ridge sticks around on ALL models through the next two weeks.  Check out the GEM (Canadian) ensemble average for Thursday the 14th:


and the ECMWF ensembles…similar setup with a cold eastern US and mild west (above the inversions):


On a side note, are you are headed out to a tree farm this weekend?  Then Sunday is your day.  It should be mainly (or all) dry.  Saturday looks like a soaker.

Mark Christmas Tree Forecast

Chief Meteorologist Mark Nelsen

33 Responses to Fresh Mountain Snow and a Very Dry December Start

  1. Jason Hougak says:

    In the past Mark commented a lot more on this blog but it seems very rare to have him around anymore. I really hope this ridge comes crashing down!!!

  2. Acting more El Niño’ish than La Niña. If you like fog I think this will be your week especially central and south valley. Air stagnation advisories by soon I bet.

  3. Sprayandpay says:

    President DT happens to be that nasty thorn all the foreign invested corporations and leaders that literally hate the USA is trying to find ways to remove but pinch their own fingers. But if they succeed even maneuvering illegally they will get shot with arrows.

    His name is Mike Pence and is our insurance against asinine globalist leaders whom view you and I as collateral damage and need to be shoved away.

  4. Sprayandpay says:

    Anyone who pretends the climate is still normal and hasn’t been altered either naturally and/or manipulation by countries that view the USA as in the way of a global regime has the IQ of a Boboklin complete with the ? or ! marks over their heads when confronted.

  5. Nahtalkin says:

    Just watched and marveled at a large beautiful skein of Canada Geese fly overhead…..after first delighting at this wondrous sight I then began to feel sad that they have to struggle with our wanton destruction of their domain and having to survive within the confines of the detritus of Western civilization. How sad the gluttony and greed of mankind has impacted these wonders of nature. Someday soon the debt will be collected.

  6. Jason Hougak says:

    🤔3″ so far at Timberline, sure hope and pray Marks 8-16″ verifies or the NWS wins.

  7. I propose we name the upcoming weather event “Melissa”…

    Think about it, it may come to you…

    • More seriously, it looks like conditions are going to be favorable for the development of “fake cold”, because the ridge will be starting out with temperatures on the cool side. NWS forecast discussion is mentioning this possibility, too.

  8. Jason Hougak says:

    ⚠️ Warning ⚠️
    Farmer Ted Advisory Issued… use cation while blogging
    NWS will upgrade to a warning if conditions continue to deteriorate

    • Boring Rain says:

      Gusts of elitism up to 80mph are possible.

    • JohnD says:

      Yeah, ‘have to say that the same dude seems to reinvent himself year after year. Some folks get their fun in strange ways (e.g. In spoiling that of others.) in any event, when/if things unduly protract, Mark’s disposal service is part of the program.
      And btw, here’s to enjoying the sun and relative calm for the next couple of weeks. Way to early to throw in the towel yet. We’ll see what Mother Nature has in store for thereafter!

    • The old dictum from the Fidonet days applies in this comments section: don’t intentionally provoke, don’t be easily provoked.

  9. Nahtalkin says:

    I sure like the KPTV toy drive and the care you all put in to make this look so attractive, not to mention all the good that comes from your effort……Has anyone noticed the KGW toy drive….Wow what a mess, toys thrown everywhere….looks more like a bad day at the Mexico City dump….probably where all these toys will end up anyways….sad to say, just landfill.

  10. Jason Hougak says:

    The long range models just look worse for mild and dry weather. Would really like the snow for the mountains.

  11. Roland Derksen says:

    Where I am December is not getting off to a dry start : We’ve been seeing almost steady, cold rain all day, and another rainy day on tap tomorrow. So a lot of snow is piling up again on the mountains. When the “death ridge ” finally arrives on Sunday (as I’ve heard) I won’t be crying.

  12. Boring Rain says:

    I feel bad for the ski resorts, can’t even get a good early start in a la niña year.

  13. Can’t really stop it so might as well look ahead to some dry frosty (at least at lower elevations) weather. Assuming it turns out to be an inversion-ey ridge and not just a warm mild one — but the forecast models do seem to be leaning to an inversion, not a surprise in December.

    That said, hope it doesn’t last 2+ weeks. That would get old. Half a week to a week of dry frosty weather would be fine by me.

    • Joshua Downtown PDX says:

      Staring mid-next week, the PNW will have the highest heights and upper atmosphere temperatures compared to normal in the entire United States. It continues that way until the end of the model runs (16th). The EURO and GFS ensembles agree. Alaska will be toasty too. That is one stubborn ridge. I love wet, cold weather, so it pains me to look at the models right now. All indications point to this being a long-lasting pattern. It might not rain after this weekend for at least two weeks. Boo!!!!!!

  14. Joshua Downtown PDX says:

    Man, this really is looking like a death ridge. Looking out 15 days and we still have weak ridging. Meanwhile, the east coast and midwest get to enjoy a prolonged cool/cold streak. On the plus side, I can wear some sweet suede boots in all the upcoming dry weather.

  15. JohnD says:

    Well an extended mild pattern in winter is both pleasant and frustrating for most of we weather geeks. Nice to see the sun, etc. for sure. But frustrating to have no weather action otherwise–and definitely no imminent winter weather potential. Doubly so when national headlines next week will include the arctic weather that will impact the eastern third.

  16. Jason Hougak says:

    Mark I like your optimism on 8-16″ for the weekend… NWS is calling for 4-8″ in Oregon Cascades. Let the battle begin!!!

  17. Jake-(Gresham near Nadaka Nature Park) says:

    Well you know what they say. The calm is usually before the storm. Let the wishcasting commence!

    An upper ridge like this when it collapses can lead to some interesting patterns as it encourages another upper ridge to develop father East as the jet stream pushes forward.

    Anything this time of year creating a proper block of the jet stream and making it go North to South along the West coast would be a solid snowstorm this time of year. I work remotely now so I am totally up for a solid Winter. Here’s for a blizzard in what we haven’t had in 80’s years! Muhahaha!

  18. Boydo3 N. Albany says:

    Nice to see the snow flakes on the blog!

  19. Nahtalkin says:

    Oh my mistake, two things and hunt overgrown Xmas saplings to put in the gigantic pick-up trucks (I suppose this could be considered a legitimate use for buying the monster). On the lighter side of life I see winter-like speckles drifting across the monitor.

  20. Nahtalkin says:

    From what all the weather forecasters seem to all say this time of year there is only one thing for the folks in Portlandia have to do is get out there and hang ‘mucho Navidad luces’!

    • GTS1K' says:

      Hey Ted, this weekend I’ll be sure to stuff half a dozen trees in my rig and honk and roll some coal when I’m on Eaden Rd. just to help put you in the Christmas spirit. Oh, and lose the insulting fractured Spanish, your English is bad enough…

  21. EY (Oak Grove) says:

    Refreshed to read the last post, saw this one. First.

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