Thoughts on Lower Elevation Snow

A few intriguing changes in the meteorological models this afternoon, so here are my updated thoughts on the possibility of low elevation snow the next few days.  First, for those that want the basics:

  • We can pretty much rule out snow in the lowest elevations through at least Friday afternoon now.
  • IF we get some sort of sticking white stuff down below 1,000′, it’ll happen sometime between the Friday evening commute and Saturday morning.
  • Right now I’d say a dusting is looking a bit more likely on the hilltops around 1,000′ maybe Friday evening and/or Saturday morning.
  • Quick warmup Sunday and beyond…very wet and windy at times next week
  • A hard freeze doesn’t look likely, maybe upper 20s here in the city either Saturday or Sunday morning.

Forecast for tomorrow is easy, strong and colder westerly flow coming in off the Pacific spells heavy snow in the mountains.  Our RPM shows 20-25″ by the time we get to late Friday, most of that falls late tonight through tomorrow night.  Snow levels drop suddenly with a secondary cold front coming through NW Oregon in the middle of the night, probably hanging right around 2,000′ through tomorrow afternoon.

Tomorrow night the snow level drops a bit further, down to around 1,500.  But then moisture appears to shift mainly to our south by daybreak on Friday.  Or 18z RPM shows just a few hundredths precipitation from late tomorrow night through Friday afternoon.   The other mesoscale model I rely heavily on, the WRF-GFS from UW, shows the same thing.  In fact they would both imply a partly cloudy day with just a few sprinkles Friday.  That combined with a continuing light southerly surface wind gives me more confidence that nothing interesting is going to happen Friday morning. 

During the day Friday and Friday night, a surface low moves from NW to SE from off Vancouver Island down to around Coos Bay, then pivots across Central Oregon.  This CAN sure be a good snow pattern for us as surface flow turns easterly.  So here’s the new wrinkle:  Some showers are shown on our RPM and WRF-GFS as the backside of the low moves by.  Our model implies a burst of showers as the sun sets Friday night.  The WRF-GFS just shows a smattering of showers around.  Something to watch closely.  And I think this increases the chance for at least a dusting of snow down to around 1,000′.  I should point out that in general models have warmed slightly.  The 12z GFS and ECMWF don’t show 850mb temps below -6.  And the 18z NAM is slightly warmer with temps staying above -6 now.  A minor detail, but significant that they don’t show it getting any colder.  I like to see a -7 or -8 with onshore flow to see sticking snow down to lower elevations.

On Saturday there is no significant change as a 2nd stronger surface low dives SE and offshore heading for Northern California.  Our RPM shows some of the stratiform precipitation making it all the way up over us by 10am Saturday; I think that may be overdone, the WRF-GFS keeps it farther south.  Once again though…something to watch closely. 

Another trend is for a quicker warmup Sunday and beyond.  850mb temps are already warmer by Sunday morning and southerly low-level flow is here by late Sunday already.  Due to that I bumped up overnight temps a bit over the weekend, and raised high temps slightly too.

Chief Meteorologist Mark Nelsen

77 Responses to Thoughts on Lower Elevation Snow

  1. Harlequin says:

    Lost power last night for a couple hours due to gusty winds and rain. I live on the border of Battle Ground and Venersborg.

  2. Hey Robby old buddy?

    You know why you got banned?

    You tried to take over my group like you also did on a few others and they can speak for themselves. I have been told by one of those other owners that you try to take control of the whole situation and I have also been told you make a problem here on Mark’s blog. My sources are also highly credible.

    You were banned because you started lipping off to one of my admins when all he did was tell you to quit posting and talking about foul language. You bud did NOT head the warning and decided to backlash on there bud so yes you did receive a warning and therefore since you decided not to listen you were immediately banned. I honestly don’t like to ban people because it is the last thing I want to do on the group. I hate being a policeman on there but I will protect my group because I do have high caliber members on there. You decided not to be one once you started giving one of my admins lip and started using foul language on there. Why would you even bring that city up on there? You had no other intention than to make a mockery of my group by putting it on there for all to see and embarrasing your own self.

    Mark, I came on here to defend myself an not use foul language in doing so. If you see it fit to ban me then fine. I can live with that. I have heard a lot about Rob and how him and a few of those other people out there that you have noted have made a mockery of your blog here and you and no one on Earth deserves that. I would have let Rob stay if he apologized simply to my admim but he did not. I have 5 other admins that will back me up on my group about how Rob has been here on your blog and in other groups. If you choose to keep him here that is fine with me since it is your blog.

    My invitation stands open on my end to you. I would post here again but I don’t think I will because I do not have time to post to only be mocked at in return. Time here on Earth is to short for ALL of us to have to have to do that.

    Odios Rob

    Thanks for listening Mark and everyone else who took the time to read this.

    Greg Carstens
    Manager and Chief Editor
    Pacific Northwest Weather on Facebook

    • Ben (Beaverton 775 ft.) says:

      Take it somewhere else, “BUD”. Nobody cares about why Rob was banned from your little geeky Internet weather group. See ya!

    • W7ENK says:

      Wow, what a warm welcome! 😦

      Welcome to the blog, Greg. I think you’ll find you’ll end up defending yourself more often than not in this crowd. The dynamic has changed dramatically over the last year, and a lot more people have sand in their craws now! It used to be just one.

    • pappoose in scappoose says:

      Best news with all this rambling, is the statement that you probably won’t bother us with more of it.

    • W7ENK says:

      Jeezuz, you people are terrible! 😯

  3. Strongest wind are likely occurring now or will before 11 PM. It seems the triple point location is the culprit for the gusty winds.

  4. Uh oh I think Crown Point just went down. Looks like a database error.

  5. austin (cornelius) says:

    I have noticed my houses’ shutters are getting stronger as I lay here in bed. (warning:DO NOT TAKE THAT THE WRONG WAY!) everytime I here it start raining the wind picks up like an uproar in a stadium…atleast that’s what it sounds like.

  6. KATX radar shows heavy band precip pushing onto puget sound basin, I expect some wind with that feature. Peak gust earlier on my home station was 36mph. 48F currently wind SW 20, presfr.

  7. Cold front has passed Astoria.

  8. Max in Fairview says:

    Very windy and gusty here in Fairview. Wasn’t expecting this much wind.

    • Danny in Troutdale says:

      Yeah me to. I used to blog from my High School but I really live in Fairview as well. I’m by Blue Lake.

  9. Runrain says:

    Wouldn’t be surprised to hear of a power outage here and there tonight.

  10. PDX-EUG is now -5.7mb, so peak gusts may not yet have occurred. PDX just reported a 40mph gust. Not bad.

  11. Mark Nelsen says:

    Check out the west end of the Gorge…SW 13 and 53 degrees at Corbett, but 2 miles east at Crown Point it’s 37 and E 20g30 mph. They are at almost exactly the same elevation. The warm layer can’t be more than 200′ straight up from Vista House.

  12. NR says:

    very gusty in hillsboro and 50.

  13. 0.51″ here and 52 degrees. Peak wind now 25 mph at 8:28.

    Here is a velocity view of the cold front coming in. Green is coming toward the radar, red is away. You can see the shift coming onto the coast very rapidly (in the loop)

  14. I just had a 34.5mph gust which is also my peak for the evening.

  15. Greg C. says:


    I keep getting asked to look at your blog and here I am with some of the others on the Facebook group Fox 12 Discussions as well as my own group Pacific Northwest Weather. I hope you decide to join me at my group, it would be great to have you there.

    Myself here I have been running the models each day to share with the others my thoughts on the coming snowpocolypse that will probably not happen in the Tacoma-Seattle area (I am in Tacoma) because the 850mb temps and 500mb thicknesses do not suggest it on the surface precip totals along with the surface temperatures especially in the afternoon hours. More than anything on Friday I see mixed precipitation in places rather than snow. If anyone gets anything below 1,000 feet in PDX and SEA I will be really amazed.

    I ran the 300mb jet forecast on the NCEP pages out 24 hours and it appears the associated upper level low never makes it far enough south for any of us. In the longer range it appear the jet sags further south all the way out to 96 hrs today on the latest 300mb jet run on the GFS. The models closer to the surface were suggesting a warmer pattern though with moderate to heavy rain in places but that has backed off now somewhat. What is new huh? When doesn’t the GFS model ever decide to jump back and forth? This is why I tend to like the Canadian GEM and the ECMWF so much more because they quite simply are more consistent in the longer portion of their forecasts. I will stick with my thoughts here and stay with decreasing moisture starting tomorrow into Friday and then dry on Saturday with an increasing chance of rain by Sunday especially late and then more then likely wet on Monday and Tuesday.

    That’s it for now. Hope to hear from you here or over on Facebook and hope this mail finds you having a great day 🙂

    Greg Carstens
    Manager and Chief Editor
    Pacific Northwest Weather on Facebook

    • Oh geez another shameless promotion of another blog/weather chat.

    • Just make sure if you’re not from Washington to make it VERY clear when you post what location you’re commenting about or else you will be warned and spoken to like a child like you just did to Larry Cloud from Gresham.

    • They banned me because I thought it would be amusing to on my post for the location to select ‘$hit, Iran’ yes, it is a real City, but not pronounced as such. I didn’t even get a warning or said anything to me, was just banned. Never mind that 3-4 people replied to it laughing even saying “$hit” as well, So you may want to think twice about joining that place it’s kind of ran way too tightly.

    • This post will backfire, just like SP last year and his shameless promotions. I’m sure they’re nice people but using another blog to promote yours is pretty lame just because they want instant success.

    • pappoose in scappoose says:

      I am a child/youngster, but I don’t like to be treated as such…I’d be banned pronto.

    • I have to agree with you there. I mean, I do understand because obviously you want to promote it somewhere, and you do want to add more people to the weather discussions, but yeah I’ve never used Mark’s Blog for any groups I am in, or run. I’ve ran a Severe Weather group for 4-5 years and never once promoted it here. I have spoke of it on a few occasions though. Also, never had to ban anyone either in that time and I have 137 members.

  16. Jethro (Molalla ~320') says:

    My max gust may have only been 32 mph, but the sound of the wind is calling me back to the blog… time to hop back on the model riding express.

  17. Check out the squall line on radar

  18. Bit gusty out there…..

    PDX-EUG: -5.4mb
    OLM-EUG: -10.7mb
    … Nice to see southerly gradients in a more respectable range.

  19. pappoose in scappoose says:

    Tower temps look like they’ve leveled off. Now we can watch em take a dive. Or not, let me go ask the Magic 8-Ball. Can you say roller coaster?

  20. Muxpux (Longview) says:

    I’m on my phone, NWS site isn’t workin well on here. Can someone (a) link me to the forecast for the 3k line by mt st helens on spirit lake highway, or just tell me how much snow they’re Lookin to get??

  21. Neba says:

    Is it possible to have micro bursts of strong wind. Over here in Milwaukie by Clackamas TC. We just had a gust which picked up my Barbq which is easy over 100lbs and threw it over on its side. I notice my neighbors fence is over too. It is not that old maybe 2-3 years. My house shuttered for a few seconds when we heard the barbq flop. Granted I know they are top heavy but not that wobbly.

    • flurball says:

      winds to 30 mph in clackamas for me as well. A bit surprising as we are usually a bit sheltered compared to other south wind sites around town. Hoping the bar-b-que was not lit when it went over:)

    • W7ENK says:

      Yeah, I’m in Milwaukie right now too, and we’ve been getting some pretty strong gusts, but they’re short lived, and few and far between. Several minutes of near calm between, actually. I’m not at my house right now, so I have no idea how strong they actually are, but I’m guessing a couple times approaching 30+? Certainly nothing capable of blowing over my mother’s BBQ, but it’s big, square, and made of brick!

      My BBQ at my house is under cover… or should be.

    • Mike near Clackamas Town Center says:

      I observed the same wind gusts around 7 PM….startled me enough to look out the window 🙂

  22. Austin (Cornelius) says:

    i am now officially reporting sideways rain and 51F

  23. I’m not sure this is a bust regarding rain totals and potential wind just yet. We’re at 0.47″ so far.. Looks like additional enhancement on the satellite as the front approaches. Rain and wind will likely increase throughout the night. Still prob get close to an inch by midnight.

  24. Triforce says:

    Does anyone know what happened to the *South Wind* and *No Snow* user that came on here a few winters ago?

  25. Punxsutawney aka HIOPHIL says:

    As of 5:30pm, .28″ since midnight in my station’s gauge here in Hillsboro, about 2.5 miles from the airport.

    .30″ in my CoCoRa’s guage.

    The ASOS sensor is definitely not working correctly at KHIO. My opinion is that it has been reading low for quite some time now, but this takes it to a whole new level.

  26. EmzinTigard says:

    Wind is definitely picking up..

  27. PaulB/Eugene says:

    As long as polar vortex is parked over AK…there is no point in getting overly excited about low elevation snow, etc in the near future…raging + EPO with lots of rain/onshore flow with variable snow levels…good for ski areas ultimately….

    Looking at odds:

    Went back to around 1930 since records in Fairbanks kept at College Obs Station….
    cold Novembers (avg temp zero or below which is at least 5 deg below normal for Nov)…22 years…only 2 had arctic events in December following…one was in Dec 90 the other was Dec 32….however 10 of those years had arctic events in Jan or Feb here in the PacNW.

    Keep the snow measuring ruler in the drawer for now before dog chews on it…will need it in Jan.

  28. Longview - 400 ft says:

    Currently 47.3 which is also the high for the day.

    The low this morning was 34.3.

    Mists now and then with low hanging clouds if you will.
    An occasional gusts of wind from time to time.
    That will wrap it up here in Longview.

    I knew something was up this morning when I saw only green and blue on the radar this morning.

  29. Up to 47.2 F
    peak gust 12.4 mph
    Total rain 0.32 in

  30. Josh (Gresham) says:

    Thursday Night: Showers. Low around 33. South southwest wind around 14 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch possible.

    Friday: Showers. High near 38. South wind between 10 and 14 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch possible.

    Friday Night: A 50 percent chance of showers. Mostly cloudy, with a low around 31.

    NWS forecast for Gresham, looks borderline on Friday after seeing 18z GFS and NAM, I bet I see some quick accumulation before midnight Friday. Just my guess

  31. PDX Weather Nut says:

    I hope the weather forecasters get rid of the “200′-500′ rain/snow, 500′ + feet snow” type language this winter…

    • Marc (East Vancouver) says:

      What do you want them to say?

    • k5mitch says:

      How about wintery mix to valley floor.

    • Chris s says:

      Agreed, it is pointless forecasting a 200ft snow level or whatever it is all the other stations do. Really once you get to the lowest 1000ft it becomes more dependent on how heavy the precip us, local micro climates, etc. They are much better off saying snow level 1000ft, but that anyone below that could see snow.

    • Jake-(Gresham) says:

      I’d have to say considering the average person in the metro area doesn’t know what elevation their house is at unless they live somewhere abnormal which would be at 1000ft+ anyways. Most just know they live in the valley and that they’re roughly at sea level.

      Give a forecast that says tells them the snow will still or not stick to the valley floor and that’s all really people pay attention to when it comes to the potential for snow.

    • Mark Nelsen says:

      I stopped that either last winter or the year before. Absolutely useless as we saw a few times last winter. Like when 1,000′ elevation in one spot got no snow yet someone at 300′ had an inch?

  32. Guess I shoulda gone to class in Hillsboro tonite. Cancelled it cuz I was not liking driving to V-Town in heavy rain & wind 😦

  33. The jet is in a good position for a wind storm next week, but as of now the models don’t show anything.

  34. W7ENK says:

    I still don’t think it’s going to happen below 1,00 feet..
    I wish it would, but I just don’t feel it.

  35. All of that sounds good to me!

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