Wintry Precip Sunday? Maybe

Whew…it’s really cold out there.  The airmass pouring out of the Columbia River Gorge and into the metro area has cooled down quite a bit the past 48 hours.  We were 44 Wednesday, 39 yesterday, and 37 today.  Add in a peak easterly gust of 45 mph and that’s cold!  You can sure see the effect the Gorge wind has on the metro area.


All areas west of the Cascades were in the 40s except Portland.  Brrr…

This time the wind has definitely been a “downslope” wind as opposed to a pure “gap” wind through the Gorge.  Check out the peak gusts…lots of locations were in the 30-40 mph range:


The cold low-level airmass will not modify at all through Sunday, which brings up a possible issue.  Models are all pushing a dying band of moisture up over us either:  Early Sunday, Midday Sunday, or Late Sunday.  You get to choose.  And we get either: Trace, .05″, or .30″.  Hmmm, what a pain to forecast.  The deal is that over this upcoming week we have a classic El Nino pattern with most rain heading into California. We just get the weak leftovers as what’s left moves north over the Pacific Northwest.  So there is no setup for a big snow/ice storm.  But as we all know, it only takes a few minutes of freezing rain to make a mess.

So to summarize…


Obviously very non-committal for now.    But I’m working this weekend…again.  So I’ll update tomorrow afternoon/evening.

Chief Meteorologist Mark Nelsen


47 Responses to Wintry Precip Sunday? Maybe

  1. '225 Tigard says:

    00z gfs looks quite interesting to me…

  2. Brian McMillan just tweeted trace to 2″ of snow on Sunday. Waaahhhhh?

  3. Farmer Ted says:

    I don’t usually share these gut feelings, but just once for the fun of it: Sunday in the metro area will be a overcast blustery day with light to moderate snow all day with about 2-3 inches! Enjoy!!

  4. paulbeugene says:

    Quick thoughts:
    Looking at NAM and HRRR, onset of precip in Eugene at 6am, PDX 10am, likely a bit later east metro.

    NAM mm5 12 km sounding shows warm nose overhead of Eugene by the time precip arrives. I have not seen 00z SLE balloon sounding yet so would be nice to see that to compare to model. If model soundings are too warm then we may get snow.

    • paulbeugene says:

      00z SLE sounding (balloon) had 850mb temp of -3.7C with dewpoint -14.7C, whereas the NAM model sounding for 00z was -0.7C and -6C respectively .
      There is hope that things may start as snow, but as Mark said, no more than an inch or two. I agree with idea that east side of Coast Range may do relatively well.

      Drive Safely

    • Andrew says:

      I bet moisture won’t even make it to the metro area until early to late afternoon, considering the past events. Also there is no moisture on current radars anywhere near us so hard to think it would come that quick in about 12 hrs. Maybe I’m wrong?

    • It’s still more than 12 hours off. The radars wouldn’t be lighting up yet.

  5. Snow Maniac says:

    It’s weird that the National Weather Service has a winter weather advisory for Woodburn and Salem, but not in the Portland metro area. According to NWS, they seem to be saying pretty much the same thing for Salem and Portland.

    • Dave in South Salem (500') says:

      Actually they did an unusually detailed job of explaining why they expect less snow to fall north of Salem. Sounds reasonable with these kinds of systems where the cold air mass in place is super dry.

  6. Tyler Mode in Battle Ground says:

    I’m running 4 degrees colder (30 right now) than last night at this time, but the wind is still blowing 25-30 mph.

    • Boring Oregon says:

      It’s already down to 24.6 now.

    • JackFrost says:

      Right at freezing and likely to get a lot colder IF high clouds don’t sneak in before midnight and warm things up to 32F again and the temps get stuck between 32F and 33F.

      Worse yet would be overcast and not a drop of moisture though at least the PNA and AO are poised to crash by day 8.

  7. Boring Oregon says:

    If it snows would it be one of those times when it’s falling from the sky but blowing across surfaces and drifting?

    • JackFrost says:

      Rural schools in the Midwest often close from just 3-4 inches of that drifting snow because the plows have 1,000 miles of country roads to plow that get covered a minute later where a steady calm 12 inch snowfall will likely only net a 1 or 2 hr delay.

      The plows do a lot better in that calm but steady snowfall.

  8. Marc (East Vancouver) says:

    At about 4:10pm, Mark posted an update on the FOX 12 Blog Discussions Facebook Page. He shared his email to the staff at FOX 12. Let me just say, it’s good.

  9. Things just got real. REAL real

    PDX NWS Forecast Discussion just issued mentions the cold pool may not go anywhere anytime soon and that east wind may persist all week although it shouldn’t be as strong. Also perhaps a chance of frozen precip all week in PDX, especially east of I-205 and the Gorge.

  10. WEATHERDAN says:

    Looks like a little snow or fz. The bonus is that it should happen on Sunday and not a morning commute. Not quite a white Christmas but close enough for me. Peace.

  11. 18z GFS still has just enough moisture to raise attention, but not enough for any kind of juicy snow event. I was hoping the models would have slanted either way (significant precip or almost none at all), but nuuuuu – they have to keep us in limbo until the very end!

  12. JackFrost says:

    I feel as if I’m reading the Capital Weather Gang (back when it was independent and free before it merged and became Premium)

    and the reactions DC gets everytime something like this happens.

    We’re really not that different.

    • Dave in South Salem (500') says:

      Even in Denver when it snows people freak out and crashes occur all over. But it has to be more than a couple inches as that occurs about every third night. There’s a slight difference but not as much as some pretend it is.

  13. marinersfan85 says:

    Government Camp is at 27 right now. There really is no warm layer. Get the cloud cover right at sunrise. If anything falls it will be in the form of snow IMO.

  14. Sapo says:

    12z GFS came in pretty dry, it basically forecast nothing to a trace of precip..interesting.

    18z NAM came in wetter than previous runs with quite a bit of precip, enough for a big ice/snow (probably ice) storm if it happened. GFS and NAM both agree on precip timing which would be about 5 PM Sunday. 850mb temps would be above freezing.

    I still think it looks suspiciously like a 33 degree rain scenario (or warmer). If the precipitation arrived at midnight Sunday it might be a different situation.

    • Sapo says:

      But if we have a high of 34 on Sunday like the NOAA is forecasting, freezing rain may pose a threat.

    • Boring Oregon says:

      33° rain in Milwaukee and ZR/snow elsewhere, got it.

    • JackFrost says:

      Actually a high of 34.1F and a low of 32.9F for most areas and light drizzle with a spit of ZR.

    • Sapo says:

      Yeah, light drizzle of freezing rain still poses a threat though haha, but 32.9 isn’t really cold enough for freezing rain so we’ll see

    • Garron (1/3 of a mile from Hillsboro airport) says:

      I think wet bulb and dew points in the 20’s will negate temps being briefly above freezing tomorrow.

  15. Dan says:

    Gorge waterfalls are looking beautiful with all the ice building up!

  16. John Liu says:

    Hmmm. I have to drive my daughter from Portland back to Eugene on Monday morning. For once, I would not welcome freezing precipitation. Well, I’ve got Blizzaks on the wife’s car so we can take that.

  17. Sapo says:

    We’ll see..Yeah models are kinda spread out on the precip arrival, NAM and GFS say it arrives Sunday around 4-5 PM, GFS is really light with the precip but NAM brings more and for longer.

    WRF brings in the precip on Sunday morning around 10 AM..Doesn’t look like it would fall as snow as the 850mb temps are above freezing..we may not be cold enough for freezing rain either. Looks like a 33-degree rain situation..we’ll see.

  18. pappoose in scappoose says:

    Hang on to your hat/car door/friend/railing/ground!

  19. Sassafrass on SE MT. Tabor says:

    28 degrees here and windy / bright enough to make your eyes water on a morning stroll. Really hoping for a few of those flakes as the precip passes by us. It’s definitely cold enough – even with the full sunshine.

  20. A repeat of yesterday morning: calm, clear, 25 ˚F, and very frosty. Trees are frosted, streets are white again. It’s been a treat to have this episode be as sunny and bright as it has been; I had been expecting to be gunked in by now. The outflow from the east has been stronger and more widespread than initially forecast, and that has made all the difference.

    Reports indicate the fogginess is beginning for some in the region, but at this stage it looks like the process is starting too late in the game for a full-blown fogversion to evolve before the current pattern ends.

  21. Andy says:

    Jefferson, OR…17 deg…7:30 am.

  22. We were forecasted to get snowflurries here starting on Monday, but now it’s been changed to rainshowers. It would be nice to get some snow for the start of the year. Sure don’t want this to be another dull, drab January! 😦

    • Reading the forecast discussion it’s clear the models aren’t doing a very good job and are flip-flopping between different solutions. Most moisture will go well to our south (typical El Niño) but it’s uncertain if and how much leftover bits of moisture will come our way for light precipitation.

  23. Diana F. says:

    Hot Diggity Dog with Mustard and Sauerkraut, IT’S A MAYBE!!!

    I totally love it when there’s EVEN just a HINT of a POSSIBILITY of Winter Weather, I really do!! “This is AWESOME”, is what Lola, the 7 y/o and therefore youngest Weather Geek in the Family, is going to say as soon as she sees this forecast on her app–which is to say, she’ll say it as soon as she wakes up because she grabs for the iPhone before she physically gets out of bed, JUST to check the FORECAST around the World!!!!

    You’ll probably hear her squeals 20 miles away!

    HA! But here I am the one, the ___ y/o and therefore oldest Weather Geek in the Family, up at 2:18 am to turn the heat on (long story based on our Electric Bill this month), and of course, I grabbed my iPhone to check the Weather ……and spotted the Awesome Forecast first!!

    It’s going to be a rousing breakfast discussion, lemme tell ya!
    Back to bed for now, although I am so excited, I’d love to wake Lola up and we can stare out the window together…..hhmmmm……

  24. Aleta- West Gresham says:

    Hey! I’m learning! 🙂 I was thinking yesterday driving home from Wilsonville that this seemed more of a downslope wind event instead of a gap wind event.

    • Paul D says:

      My thoughts exactly. When I was outside briefly yesterday, I could tell that the downslope was blowing through my neighborhood 🙂

  25. Marc (East Vancouver) says:


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