Weather action is picking up! Stormy tonight, snow in Gorge, & lowland snow possibilities

NOTE: Nowadays I post to our station website, then when I have time I copy the post to this site. It will have formatting errors and images you can’t enlarge. Unfortunately there is no way to get a notification when I post over there, but for the “full experience” check out posts there.

8pm Tuesday…

We had 2 weeks of high pressure and dry weather in mid-November, but now it’s payback time. I’ve got 3 weather items to cover this evening: stormy night tonight, heavy snow in Cascades/Gorge, & could we see snow in the lowlands later this week.

(kptv)

First, we’ve got a soaker headed into the PACNW right now. It’s a cold front and that’s the leading edge of another “maritime polar” or “maritime arctic” airmass. That means cold/dry arctic air has dumped out over the ocean and is moving toward us. That cold front has a lot of rain associated with it. I expect about an inch of rain (or a bit more) overnight in the western valleys of Oregon and SW Washington. Then the wind; southerly gusts will likely reach the 35-45 mph range around 11pm-2am just ahead of the cold front. Expect a few scattered power outages during the night

(kptv)

Tomorrow will be uneventful in the lower elevations with light wind and scattered showers

GORGE SNOW

For the first time this season we’ve got a (very shallow) cold airmass streaming westward through this sea-level gap in the Cascades. Add in abundant moisture moving in overhead and it’s the perfect recipe for a snow or ice storm. It appears this time it’ll be mainly snow, with a little freezing rain mixed in toward sunrise when the cold airmass thins out. Almost all the action will be east of Multnomah Falls. The cold air is so thin at the west end of the Gorge that it’s barely streaming over the top of Crown Point! Up around 1,500′ nearby it’s well above freezing. The cold air is thick enough on the Washington side to support snow a few more hours of snow NORTH of the Columbia River.

Weather Blog Images
Weather Blog Images(kptv)

Temperatures will warm tomorrow midday/afternoon and I-84 should be fine the rest of tomorrow.

CASCADE SNOW

There is plenty of snow on the ground in the Cascades and we’ll add 1-2′ additional tonight through Thursday morning. This will be the best December 1st snowpack in about 15 years!

(kptv)

Worst travel conditions in the Cascades will be tomorrow morning with lighter snow in the afternoon.

LOWLAND SNOW POSSIBILITIES

This is probably what many of you want to know…Will we get snow in the I-5 corridor between Longview and Eugene? Possibly, but I still don’t see a setup for widespread snow in the cities. The first two “close calls” this week have ended with nothing. That was Monday morning’s snow in the hills, then a brief “flurry storm” in a few spots this morning before the airmass warmed up. Models handled both well, although precipitation arrived a bit early today.

For the next 2 days, I think our commutes are clear except for Thursday morning. On that day we’ll be in a chilly airmass with scattered showers roaming about including during that morning commute. Typically this isn’t a significant snow producer west of the Cascades in the lowlands. BUT, if it snows a Trace to 1″ Thursday morning where YOU live, it’s a big deal to YOU!

The cold airmass behind tonight’s cold front will bring sticking snow down to around 2,000′ late tomorrow and around 1,000′ Thursday morning. Considering it’s just scattered showers, that usually means a few spots in the hills get a dusting and we don’t see anything other than a rain/snow mix in the valleys. BUT, if we get any sort of steady/heavy showers, that sticking snow can come right down into the lowest elevations. For the geeks, we’re bottoming out around 520dm thickness and 850mb temps -6 to -7 Thursday and Friday…that’s cold, but not “guaranteed” category for snow in the lowlands. Some models have been hinting an organized band of showers could develop tomorrow night or Thursday morning. The Canadian HDRPS model, HRRR, & NAM-3km imply this could happen and all 3 are producing measurable snow across at least part of the Portland metro area during that time. So…we will see what the evening GRAF model shows in an hour or so. Right now it thinks a few spots could get “stickage” early Thursday morning…stay tuned!

(kptv)

A repeat is possible Thursday night into Friday morning, but in general I’m thinking the vast majority of us in the I-5 corridor from Longview to Eugene will not see “sleddable” snow through Friday.

It could be a different story after that time…

Another cold upper trough drops down offshore Friday and spins up another wet frontal system. Models are all over the place on this one. The normally cold GFS thinks we’ve got a snow and then ice storm Friday night into Saturday morning. The ECMWF is much drier and has the system farther offshore. But it IS cold enough with a strong easterly Gorge wind that moisture would be in the form of snow/ice. So Friday evening/night is another possible “event” I’m watching closely. There is also plenty of cold/dry arctic air lingering just north of us through early next week. That means at any time some of that could get pulled south and interact with Pacific moisture as we’re seeing this evening. Winter is here for the forecasters and it’s busy!

That’s it for now…enjoy the stormy night.

44 Responses to Weather action is picking up! Stormy tonight, snow in Gorge, & lowland snow possibilities

  1. Doinko - Bethany says:

    Hmm, all three main models give us some snow on Sunday.

    • Andrew says:

      You’re correct but models are also picking up very weak precip band that likely wouldn’t even make it to surface. With marginal temps we’d prob need heavier showers to see any real snow. This thing will be running on fumes by time it gets to Portland area. The dry air will also zap it of some energy. I sincerely hope i’m wrong but seeming like a snow event this weekend is highly unlikely. That said, enough variables at play to keep an eye on things. The offshore flow should pick up more tonight and tomorrow and lower our dew points. just don’t appear to have a lot of precip to tap into. it’s always something getting in our way! haha

      • Doinko - Bethany says:

        All models seem to be showing some sort of blowup of precip around the Portland area, maybe they’re showing some convergence here. That would be nice even if it’s really unlikely so far

      • Joshua Lake Oswego says:

        Exactly, Andrew. The reality is that there will be very little QPF to work with. If anything falls, it will be light. Temps should be in the mid-30s with decent offshore flow. 850 temps are barely below freezing. My opinion is that some flurries are the best we will muster. More likely is that we will see a little cold drizzle.

    • Joshua Lake Oswego says:

      Ha, look at the 00z GFS. Zero support from any hi-res models. Curious to see what the WRF-GFS shows at 4km. Of course, all of this is entirely dependent on where the wraparound showers even hit aside from the marginal atmospheric conditions.

  2. Evan -- Cedar Mill says:

    Non-event. Called it about a week ago.

  3. Andrew says:

    Models appear to have nailed today’s low. Precip taking dead aim at olympics leaving Portland dry. It does look like we may see some wrap around activity later in weekend, but meaningful snow threat looks minimal on account of both marginal temps and a system that will be very low in energy by time it reaches us. I’m still holding out hope that things might set up favorably for next week and beyond but no model support at moment. Alas, looking like another near miss.

    • tim says:

      Looks like a pattern change to warmer and wetter going into mid and late December, both cfs and cansip models are also showing a warmer than normal January not to be taken at face value of course, well see.

  4. Mountain Man says:

    Another 3.5 inches last night brings me to 11.5 inches on the season so far, about 30% of my average for an entire winter here which is 38 inches. Not a bad start here in the foothills considering how early it is.

  5. WEATHERDAN says:

    Light snow in South Salem with a current temperature of 36. Winds have shifted to 350 (NNW) at 7mph. Merry Christmas and Peace.

  6. Ken in Sheridan 300' or so says:

    My bad …..previous post should read “East/Northeast”

  7. Ken in Sheridan 300' or so says:

    All done …. beautiful while it lasted …. shower going west/ northwest … 35.1 and sun now …

  8. Ken in Sheridan 300' or so says:

    Heavy snow shower continues …. Temp 33.8 , no wind, sticking to everything now … half inch at least ??

  9. Ken in Sheridan 300' or so says:

    Temp 34.0

  10. Ken in Sheridan 300' or so says:

    HEAVY downpour of snow right now! Sticking a bit ….. Merry Christmas!!

  11. Zach says:

    Looks like PDX came up just shy of average rainfall for November.

  12. OC550 says:

    Had a dusting of snow in the bark dust this morning at 550 ft in Oregon City. Just conversational snow. I’ll take this over a 2 week dry spell during winter.

  13. Andrew says:

    Temp at my place in SE Portland has dropped about 3.5 degrees since midnight, for what that’s worth.

  14. Ken in Wood Village says:

    When I was going to my car this morning, I believe it started to sleet because of the sound I was hearing it hit the ground. I know it’s not hail because that would mean it would have been a thunderstorm because of the convection hail needs to form hail. Plus, I looked at my radar and it was a very small shower with light green color.

    Don’t be surprised if you see sleet or snow this morning. Oh, the NWS forecast for Friday night through Sunday shows a chance of just snow showers because there will be a east wind event bringing cold air through the Gorge. At this time, it doesn’t look like anything major but if that low pressure comes closer, maybe we could see something major in the form of a snowstorm. We need to watch this closely.

    Have a good day 😊 ❄️

  15. Anonymous says:

    I believe when he first switch things over, he made an actual comment in the comments that we can still chat here on the legacy site but that he doesn’t want to moderate comments anymore so… I’m assuming that’s why you can’t comment on the station blog site.

  16. WEATHERDAN says:

    Mark how do you add a comment on you new blog site? Please let us know how to do this please. Or is it that you no longer desire our comments. Peace.

  17. WEATHERDAN says:

    No AR but still got 1.29 inches today. So more flooded basement. Looks like several borderline chances for lowland snow over the next two weeks. Who knows. Peace.

    • X says:

      Flooded basements sound definitely La Nina like. Nothing like a good old local flood to start the winter. 🙂

  18. Ken in Wood Village says:

    NWS just posted this about tonight. The HRRR still shows rain switching over to snow or snow/rain mix tonight into tomorrow. I hope more towards snow 😉❄️

    Special Weather Statement

    SNOW SHOWERS WITH LIGHT ACCUMULATION POSSIBLE TONIGHT THROUGH
    THURSDAY MORNING COMMUTE…

    Snow showers expected tonight through the Thursday morning commute in the lowlands of the lower Columbia, Portland-Vancouver Metro area, and the Central and Southern Willamette Valley. Snow will be spotty in nature, and will be combined with rain through most locations. Some areas, especially those above 500 ft, may see minor accumulations while others will see no snow.

    While accumulation may not be heavy, be sure to travel with care as roads may still be slick in spots.

  19. lurkingsince’14 says:

    Massive thunderstorm/hail rolled thru sylvan hill area around 2pm. Starting to feel like winter – things look interesting for the next couple weeks!

  20. runrain says:

    NWS forecast for today: “steady temp around 37°”. It’s 46° right now. I don’t think they have much confidence in their forecast.

  21. OC550 says:

    The mountains are getting pummeled which is great for reservoirs and winter sports. Seems like the low snow levels 1k – 2k will continue for a while. Would love to see a couple days of snow in the valley. We’ll see how it goes. It’s not even December yet.

  22. ocpaul says:

    Big picture is interesting. Ridging near Greenland is splitting the polar vortex, sending a portion toward the west coast of Canada.
    As always in the PNW, fingers crossed.

  23. Tanis Leach says:

    12z Euro has Corvallis/Eugene scoring late weekend. We shall see.

  24. Roland Derksen says:

    Pretty good snowfall here last night- about 5 and a half inches. it stopped shortly before midnight, and temperatures stayed just above freezing, so it’s slushy this morning. However the sun is shining, and the mountains look wonderful.

  25. Joshua Lake Oswego says:

    The GFS is unfortunately caving to the Euro on the Friday night/Saturday morning low and keeping it too far off shore. There is huge potential with this one. In the most recently-modeled scenarios, extreme NW Oregon scores huge while the valley is left high and dry. Bummer.

    • Joshua Lake Oswego says:

      The 12z has a Portland bullseye early Saturday morning.

      • Andrew says:

        Yeah this could be the ultimate close call but leaning towards EURO, although I think the model is overdoing the stall out off coast.

        • Joshua Lake Oswego says:

          Yea, no chance the operational GFS verifies. It’s on its own. The WRF 4km gives maybe an inch. Resolution matters in these marginal situations.

  26. WEATHERDAN says:

    First. Peace.

  27. JohnD says:

    Wow! Thanks!
    Really fun stuff for we geeks.
    Your input so invaluable Mark.

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