Snow/Ice Possible Later This Week

4pm Monday…

Late Evening Edit:  A few new thoughts at 10pm with all evening models in nowupdates in red

It’s been a very gloomy day out there with low clouds hanging over most of the metro area.  The good news is Tuesday will be a much brighter day; I expect clouds to break up to partly to mostly sunny skies in the wake of a cold front passing through the region.  The air coming in tomorrow is cooler and drier, thus the increasing sunshine.

Of course what we all care about is that Wednesday-Friday time period I mentioned in the posting Sunday night:

THE BIG PICTURE

The 2nd half of this week we’ll be in a “conflict zone” in the Pacific Northwest where the colder air from the north moves down under milder/moist air above.  That “zone” seems to want to hang out somewhere near the Oregon/Washington border Wednesday through Friday according to most models.  But details are very uncertain through that whole 3 day period and I don’t have a lot more info to give you this afternoon…we’re just going to have to wait until we get closer (Tuesday) to see if we can get some better forecast agreement among the models.  But I can give you a few more tidbits this afternoon that might help with you late week decision-making…

HIGH CONFIDENCE ON THESE DETAILS:

  1. A cold east wind arrives in the Gorge tomorrow and tomorrow night.  It’ll blow quite hard Wednesday-Friday in the Gorge and east metro
  2. Expect high temperatures mainly 32-38 in the metro area Wednesday-Friday
  3. Temperatures remain at/below freezing Wednesday-Friday in the Gorge.
  4. At some point we’re going to see sticking snow and/or freezing rain in at least portions of the metro area during this period.
  5. The Gorge turns snowy/icy again with a little snow late tonight/Tuesday AM, then quite a bit likely Thursday/Friday.

LOW CONFIDENCE:

  1. Will we actually see snow sticking in the metro area Wednesday?  Possibly, but as of now most models are mainly dry for that day.  This could change. (10pm update)  All models except our RPM are pretty much dry Wednesday.  I’ve taken the chance of anything other than flurries out of the Wednesday/Wednesday night forecast.
  2. How much moisture Thursday/Friday?  Some models are mainly dry through at least midday Thursday and then light freezing rain Thursday night/Friday AM.  Others have more widespread snow Thursday before a changeover.  I’m sticking with a later arrival (sometime Thursday) for now. (10pm update)  Definitely a later Thursday & Friday event showing up now.  Thursday might even be dry to start.
  3. The cold air mass over us Wednesday-Friday isn’t nearly as cold as what we saw in the first half of January.  That means it’s possible even IF we get a bunch of precipitation Thursday/Friday, some areas could be above freezing west of the Cascades = less frozen precip.  Another reason the forecast is very tricky.

Will there be school closures?  Not through Wednesday, but we’ll see about Thursday & Friday.  (10pm update)  It’s possible no road issues until later Thursday

Note the preferred ECMWF model is quite dry and/or not quite cold enough all the way through Friday for most areas west of the Cascades:

ecmwf_snow_fridaymidday

While the 18z GFS has a dusting to an inch or so.  gfs_18zsnow

The 12z WRF-GFS is slightly snowier.

wrf_snow_12z

Our RPM is similar with very light snow totals.  But it also thinks it’s above freezing even in the metro area all the way through Thursday midday.  That’s unlikely:

rpm_snowaccum

The big message here is that as of this moment no models are showing a huge snowstorm or major ice storm in the western valleys.  But we all remember the January 10th snowstorm though when all that moisture appeared out of nowhere!  A good reason to keep an eye on trends in modeling and satellite imagery of course.

Stay Tuned!

Chief Meteorologist Mark Nelsen

38 Responses to Snow/Ice Possible Later This Week

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

    Perhaps the most interesting dynamic of this setup is the majority of the arctic air coming into play into the PNW. Comes by spilling over the mountain range of British Columbia out over the ocean. Usually, the ocean water moderates this air leaving us with just cold rain. This is intriguing indeed and will be exceptionally tough to forecast day by day (IMHO):

    GFS(850mb):
    http://www.pivotalweather.com/model.php?m=gfs&p=850th_nb&rh=2017013118&fh=108&r=na&dpdt=

    Equally almost as interesting. We have a low pressure system that’s not forecasted to make landfall. It just goes South to North along the coast and slams into the high pressure and cold air in British Columbia – gnarly and unique as well:

    http://www.pivotalweather.com/model.php?m=ecmwf&p=sfcmslp&rh=2017013112&fh=72&r=na&dpdt=

  2. Jason Hougak says:

    Back from Maui just as the weather action picks back up!!! GFS showing another round early next week after Thursday-Fridays winter event.

  3. Diana F says:

    Wowza, snow through next week??

    https://www.wunderground.com/us/wa/vancouver

  4. WEATHERDAN says:

    Looks like a lot of cold and snow headed our way over the next 10 days.

    • JJ78259 says:

      That 7 day weather for Portland dropped from 51 to still dropping that sure changed in hurry!!! We have a 86 degree temp coming up next week!

  5. Mokihana says:

    We’ve been getting rain in Damascus and Gresham.

  6. Roland Derksen says:

    Perfect day here to finish off January: Clear skies, gentle NE breeze, but it’s going to get cold tonight.

  7. runrain says:

    North winds ramping up in Bellingham. Here we go!

  8. Josh "The Snowman" from gladstone, OR says:

    Just remember. And this is for you as well, Mark. Models were very dry last time and look what happened!! So hard to forecast the convective nature these scenarios can have with such colliding air masses. And models always underestimate this setup. I’m calling for at least 3-4 widespread inches with some areas west and south of downtown probably getting another 6-8.

  9. W7ENK says:

    So, it sounds like another one of these is in order?

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

    Monday, January 30, 2017
    Another Cold, Snowy, and Icy Period Will Portland AGAIN:

    http://cliffmass.blogspot.com/2017/01/another-cold-snowy-and-icy-period-will.html

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

    Very good snow coverage going into this.

    NOAA:

    Intellicast:
    http://www.intellicast.com/Travel/Weather/Snow/Cover.aspx

    Weather Channel:
    https://dsx.weather.com/util/image/map/WEB_Snow_Cover_1280x720.jpg?v=ap&w=1280&h=720&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0

    What do you guys think? Winter for the record books for most living folks in the PNW? I think the WWII vets I care for would scoff and could jog up their memory to bring something we’ve had more significant than this Winter. But I certainly haven’t seen such an active Winter overall.

    • JJ78259 says:

      Pretty impressive winter not to long ago bloggers were speaking of Global Warming was going to kill anything other than cool wet winters with California Temperatures all spring long into summer. I guess there needs to be a reboot here. Winters of the past can still happen could we be heading into a cooler scenario for the PNW??? We will be pulling out of the Paris Global Warming Treaty so we may be heading in a new Direction.

    • Anonymous says:

      1968-1969 and 1978-1979 were both colder and snowier than this Winter. I would put us 3rd so far. I f the snow and cold forecaster for the first 10 days of February pans out I would move us up to 2nd and maybe even 1st. But 3rd so far. Peace.

    • Jake-(Gresham near Nadaka Nature Park) says:

      Yeah I mean WWII vets can bring up this from their childhood but anything after is probably beaten? We’ve got some interesting data to compare once this Winter is over IMO!

      Historic Hood River (Feb 9th, 1929):
      http://historichoodriver.com/index.php?showimage=548

      The frozen Willamette, 1924:

    • Jake-(Gresham near Nadaka Nature Park) says:

      Of course that is assuming this bellow average Winter trend in temperature continues. We are approaching some interesting territory.

  12. Tonight’s EURO says don’t put away the chains, ski’s, snowmobiles, etc. just yet

  13. marinersfan85 says:

    0Z Gfs gives ya a whiplash after this weekend.

  14. Scooter says:

    Hey you guys and gals on the blog are just a hoot! But I mostly tune in to see what Mark has to say, and that’s why I watch kptv 12, you folks can mine the data and just maybe give us a little more heads up than those other broadcasters that report just the NWS weather.

  15. Diana F says:

    <<—–Binge Watching “Life Below Zero”, Seasons 1 thru 8, in preparation of impending weather 😂

  16. Paul D says:

    Let’s set some February records for cold/snow/ice/store stampedes!!!!

  17. Josh "The Snowman" from Gladstone, OR says:

    Uncertainty forecast warning.

    Let’s just call it what it is. Mark knows more because of the tools at his disposal but it doesn’t give him any certainty. Prepare for pretty much anything at this point.

    • Paul D says:

      I’m glad Mark tells it like it is. If he can’t be sure, that’s fine. I know we’ll hear from him when he has more information.

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

    The most important question to ask here is. Do all the grocery stores have enough toilet paper for the ensuing stampede?

    Puts out hate for donations on anyone that wants me to wait in line first thing at the grocery store for this vital supply tomorrow morning.

    Insurance policy:

    I’m 210lbs and can out run just about anyone. Mileage may vary depending on the requirement to dodge children, strollers, wet aisle floors, and the occasional toy in the store due to my height becoming an impediment on my ninjaness.

    If you would like to hire me as your personal ninja please do understand the encroaching panic may limit my response indefinitely due to the improbability of making it out with all supplies intact. Without the use of a helicopter supplies may be otherwise out of stock to and from the store.

    To reach me please call:

    503-we really need-salt on our roads badly badly.

    Thank you.

  19. JohnD says:

    The waiting game…as is the case for virtually all Portland winter weather events. Partly in a wishcasting mode, and given the predominance of the season so far, my instincts say that we get an accumulation–greater or lesser–at some point during the period.

  20. Aspiring Windowlicker says:

    Looks like Central Valley will miss all the frozen excitement once again.

    • boydo3 N Albany says:

      Let’s hope so. My wife works at Albany schools and will be making up 5 snow days. Enough already!!

  21. JERAT416 says:

    Hmmmmm….. well maybe winter has one more event left to throw at us. Thanks for the update Mark!

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