Snow Tomorrow: Where and How Much

Some of you in the lower elevations will see snow in the air by this time tomorrow night, but I think anyone below 1,500′ will have to be in the Gorge to see it. 

First, the basics:

– Cold again tonight and a real chilly day tomorrow with some fog or low clouds mixed with solid incoming cloud cover by 3-4pm.  We’ll be lucky to hit 40 degrees here in Portland.

– Rain arrives during the evening commute, or slightly later here in Portland.  Sticking snow will be at/above 1,500′.  It’s possible some of you in far western Washington county or northern Clark County could see snow in the air to lower elevations, but I don’t think it’ll stick.

– It starts as snow and stays all snow anywhere east of about Multnomah Falls in the Columbia River Gorge.  A trace to 2″ (up to 2″) is possible from Multnomah Falls out to The Dalles by the middle of the night.


A couple things to note on the models this evening:

1. In the past 24 hours, models have been showing more of a split with the incoming upper-level trough.  More energy heads south of us.  As a result, we don’t get a surface low to the north.  That means no wind tomorrow except for a continuing chilly easterly flow (not too strong) out of the Columbia Gorge.  This would be a great setup for snow here in Portland; no warming south wind, but the airmass isn’t that cold over us and isn’t all that cold coming out of the Gorge either.  And then there is that pesky lack of precipitation issue…see #2

2. More split = drier as well.  Our RPM is showing a grand total of .13″!  The WRF-GFS shows .05-.15″ for the entire metro area and the Gorge too.  Okay, maybe 2″ snow maximum in the Gorge.  What a waste of chilly air eh?  This also doesn’t help with evaporative cooling here in the metro area tomorrow.  You want steady/heavy precipitation to drag the snow level down.  That’s not going to happen.

3. This is the pattern in which we sometimes get surprisingly low snow levels over western Yamhill, Washington, and Columbia counties.  I don’t see the usual “signature” on models for this.  Just not cold enough and not enough precipitation at the same time.

In the Cascades:

Sorry skiers, but this looks pathetic on Mt. Hood.  We need some snow badly;  after this event, the next decent chance is well into the first week of the Christmas Break.  It appears that the biggest two weeks of the ski season (at least in numbers of people) will begin with hard-packed icy stuff off the main runs and a thin snowpack.  Obviously lots of fun for the casual skiers, but no sign of fresh snow.

Chief Meteorologist Mark Nelsen



66 Responses to Snow Tomorrow: Where and How Much

  1. David B says:

    Despite a comment on an earlier post to the effect of taking things as they come, I must say that this lack of storms is really starting to get old.

    Maybe it’s going to be the winter where we finally go back to having cold/snow events in January, which is when it used to seem like such things typically happened (as opposed to before/during the holiday season).

    Well, I can hope at least …

  2. Cap - Hood River says:

    Lite snow falling in HR

  3. john says:

    now precip here yet but temp is dropping nice

  4. Shawn in Scappoose says:

    Thats a positive on the splat test here in Scappoose

  5. Looks to me like the center of low pressure IS coming in to the south. That should make things more interesting.

  6. SnowedIn - North Plains says:

    I believe it is currently snowing here! The flakes are wet and moving fairly fast, and are pretty small, but from what I can tell it is snow!!! I’ll let y’all know if it picks up enough to really tell.

  7. cherie in vernonia says:

    frozen precip here…all the gravel out in the Uhaul lot is white…starting to stick to the hood of my truck…just now flakes are getting bigger.

  8. muxpux (Castle Rock, WA 175') says:

    temp dropped from 40 to 36 here, no precip yet….

  9. W7ENK says:

    Sprinkles of rain just started here in Milwaukie…Game over, folks! 😦

  10. JohnD says:

    Close call particulary in certain spots–like
    E. County. It won’t be much if it happens as
    all. But it sure would be nice to see even a
    few lowland flakes! And “fake” or not, this
    has at least been a seasonably cool/cold
    December so far for sure. And more to come.
    Hopefully we WILL get the “real” deal next

  11. Jeannie says:

    I am not ever going to post again but I wanted you weather people to know I Love reading this blog! I read you and listen to Mark over any other weather stations. Not that you all do not get a little worked up but it is better then reality t.v. 😉 Keep on posting for me!

  12. W7ENK says:

    Totally non-scientific, but that sure does look like a snow sky…

    Time to start watching the GOLU model very closely, I think! 🙂

    • EmzinTigard says:

      That’s my kind of weather predicting.. I have said that many times on days just before we had snow. So I’m w/ you on that.

    • alohabb says:

      That kind of weather predicting is the same that other TV Mets use! Surely not Mark though! :}

  13. PaulB/Eugene says:

    Wed 13:00
    Not all that excited about a small risk of spotty “fake” snowfall. Hopefully the Mt. Hood ski areas can at least squeeze out a few inches of snow from this tonight.

    Pretty clear that once we get past tonight’s weak system, there is not much precip until probably after Christmas. 18 and 00Z GFS ensemble means ramped up precip for the end of Dec, but 06Z pulled back a bit, then 12Z is increased once again…it looks like there is a reasonable chance of at least a couple inches of liquid precip at valley locations before New Years’s Day, still leaving us with a pretty dry month overall though.

    Nighttime lows will be continue being below norms for the year, below freezing, well into 20s, but not as cold as earlier this week…and we may still have relatively cool days at lower elevations…Dec has a good chance of having avg temps in the mid-upper 30s when all is said and done.

    Still think that January will be a much more interesting month. I have been eyeballing the CFS runs all season, and honestly, only about a half of the runs have been showing significant arctic intrusions at some point during the winter (for the PacNW). Today’s run has arctic event around 1/19. Probably better for the economy that a significant snow event does not happen until after the holiday season anyway. If I recall…the 2008 event negatively impacted PDX businesses (other than Les Schwab)

  14. no snow today! Southerly winds and temps well above freezing below 1,500-2,000ft. Not even enough evaporative cooling. The precip it just to light. Pretty lame!

  15. pappoose in scappoose says:

    Hahaah! Rod Hill has submitted his CYA statement….says if the timing is right “there would be some cold pockets that could see a period of light snow tonight.”

  16. It is 37 here.

    Yesterday at 11 it was 35 with full sun…

  17. pappoose in scappoose says:

    Langley Hill

    Message Date: Dec 14 2011 18:34:35


  18. NR says:

    12 z gfs is terrible – split flow through 300 hr

  19. Derek Hodges says:

    I supposed the one good thing is that the cold pool in the basin won’t be displaced so we don’t have to start from scratch. It would be nice if they got some snow over there but its really quite doubtful. At any rate we can hope.

    I agree with all of you that for various reasons any snow is highly unlikely, but still not impossible per say, just close.

  20. W7ENK says:

    Okay, so here’s how I’m looking at our upcoming weather… there’s a greater than 95% chance we won’t see any snow flakes anywhere around the greater Portland area tomorrow or tomorrow night, however in the Gorge, if they can manage to squeeze out enough moisture — and that’s a big IF — then maybe we can start paving the way for colder air later on down the line. You see, if we lay down a nice blanket of snow all throughout the Gorge, and especially if we can get any of that over on the east side of the mountains, and then we switch back to a dry, clear pattern, that becomes a perfect recipe for optimal radiation a cooling on the east side! We could conceivably see low temperatures on the eastside in the single digits, or even down to 0 or below over there, and without any sort of real arctic air… I mean, if the Alaskans and Siberians don’t want to come down here and play in our yard, then Eff those guys and their stingy snow-hoarding Bee-Ess! We’ll just make our own arctic air, dammit! >_<

    Next, we start funneling that frigid, Made in Oregon pseudo-arctic air down the snow-carpeted Gorge, we here in the Western valleys start freezing our arses off, get that cold air nice and deep, then just add water!

    It's a nice story, anyway… 😆

    • Ryan (Walnut Grove) says:

      Whatever snow falls in the gorge tonight will be long gone by the time we get a shot at any real event here in Portland.

      A snow carpeted Columbia Basin would be far more helpful but that won’t happen either. A cold gorge doesn’t really do much for PDX… A cold Columbia Basin gives us the big dome of cold air to draw on.

    • W7ENK says:


      No one???

      I’s trying to get even just one person to crack a smile… 😦

    • W7ENK says:

      Oh, you snuck one in under me…

    • josh says:

      ha lets do it

  21. bgb41 says:

    12/13/2011 Oregon (All) Temperature Summary

    High:54 at DUNES( 120 ft)
    Low: 39 at RED MOUND(1753 ft) & CW3485 Port Orfo(400 ft)

    High:20 at KB7DZR Joseph(3984 ft)
    Low: -1 at CRAZYMAN FLAT (6100 ft )

    Largest Diurnal Change: 42 degrees
    CRAZYMAN FLAT (41/-1 ) (6100 ft )

  22. Juan benedicti says:

    Well this sucks i guess we have to wait even longer :/

  23. PaulB/Eugene says:

    Looking at the GFS ensemble mean once again…the 00Z run has over 2.5 inches of liquid precip at PDX in the next 15 days, most of it beyond day 7. Canadian ensembles also now indicating significant pattern change beyond day 7.

  24. This December drought can’t last much longer. Active weather will soon return, which will seem all the more impressive when compared to the unseasonably tame weather of late. I would think that a major pattern change would be expected by Christmas, certainly no later than New Years Day. Enjoy the cool dry days — they won’t last.

    • TAGinGresham says:

      I was thinking the same thing Peter, I don’t know 90% of what some of you on this board know, but doesn’t it kind of make sense that we will be “compensated” for these cool/dry days with a more active weather pattern? Of course we’re dealing with Mother Nature here, but I can’t see us going from this dead pattern to a pattern that’s just a little bit more active. Maybe it’s wishful thinking on my part, but I want to be compensated and then some, with a great snowstorm and blizzard! Then maybe a nice layer of ice followed by more snow. I can dream can’t I???

    • We thought that back in 1976, too. January 1977 was a repeat. Hope that is not the case this time…

      Up to 35° now.

    • W7ENK says:

      Unfortunately, this “compensation” you speak of TAG does come, but only when it’s too late in the season for a good snowstorm — hence the last two crappy summers. Let’s all hope this winter/spring/summer do NOT follow suit! 😕

    • Mark Nelsen says:

      1988 saw a big turnaround from mid December to mid January. That was a La Nina winter.

    • Actually the winter of 2000/2001(a La Nina winter) was very similar to this. Very low precip and lousy snow fall in the Cascades and N Rockies. I know because I booked a ski trip in Montana that winter based on the prediction that the winter was gonna be a killer snow year. FAILED! I remember riding the lift with a guy from New Hampshire. His comment was “why the hell did I come all the way out here to ski on this meager packed ice when I could have stayed home and had powder days every day?”
      So don’t count out the possibility that we could just continue to meander along with the high pressure funk. I hope it changes soon, tho. I really do!

    • Ryan (Walnut Grove) says:

      I’d have to agree with Paul’s assessment that by the end of the year we will see things ramp up again… Likely mild pacific systems to get things going then perhaps an arctic blast by mid/late-January.

    • NR says:

      I’d still say 2004 is a very close comparison to this winter, thus far, and it stayed lousy straight through February.

    • Andrew (West Hills) says:

      Maybe this is the year that January finally goes back to being a snow producing month for areas west of the Cascades.

    • Garron Beaverton says:

      We thought that ridge in the middle of the country was gonna budge last winter, it did in late September!!!!

  25. pappoose in scappoose says:

    Hahaah! Here’s the CYA statement from the NWS:

    National Weather Service Portland or
    844 PM PST Tuesday Dec 13 2011

    The chance for any snow in the metropolitan area is very low…given the dry air mass in place limiting the chance widespread fog tonight and Wednesday…so temperatures will likely approach 40 degrees for most of the valley by the afternoon. The kicker to this will be for any locations that do fog in a bit more than currently expected. This would obviously put a wrench in the forecast.

    A low chance of snow, means there is a chance!
    And I really like it when there’s a wrench in the forecast. Hahaah!

  26. W7ENK says:

    It won'[t snow tomorrow, silly! 😛

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