Wet New Year’s Eve, Plus Big Weather Change POSSIBLE For Early 2020

7pm Sunday…

It’s been a mainly dry weekend across the metro area, in fact officially we didn’t have measurable rain in Portland

Rain Metro Today Databound

We won’t see any rain tomorrow, and then maybe .25″ to .50″ Tuesday afternoon/evening before the rain “clock resets” for 2020 at midnight Tuesday.  This means 2019 will likely go down as the 7th driest on record in Portland.  Those records at PDX go back just under 80 years.  This is our 2nd consecutive dry year after a few wet ones.  By the way, there is no significant long-term shift in our precipitation; go back 100 years and we picked up about the same as now.  Temperature of course is a different story

Rain Year PDX

Speaking of 2020, how is it looking for your party plans weatherwise?  The good news is there won’t be snow or ice ANYWHERE over or west of the Cascades.  A very warm airmass surges in with southerly breezes Tuesday afternoon.  Sticking snow will be well above the timberline on Mt. Hood.  Here in the lowlands a strong westerly flow overhead means we’ll be somewhat “rain-shadowed” by the Coast Range.  It’ll be rainy at times Tuesday evening/night, but nothing heavy.  South wind may gust 30 mph or higher too.

New Years Eve Fcst

Up in the Cascades it’ll be a different story.  All models produce a LOT of rain from 8pm-4am New Year’s Day.  I highly recommend skiing during the daytime Tuesday when rain will be light.  It should be a downpour during the overnight hours, especially leading up to midnight.  Take a look at 24 hour rainfall from the WRF-GFS model, ending at 4am Wednesday


You can see those black areas approaching 3″ rain in the Cascades.  Yet some spots on the valley may see only one tenth that much (Hillsboro).  That’s a clear signal of strong “orographic” lifting.  A strong flow of air perpendicular to mountain ranges (westerly in this case) forces moist air to rise, releasing LOTS of rain!

So we’re wrapping up a drier/warmer than average December.  That’s after a drier/average (rain/temps) November.  The main feature of this cold season so far is a persistent split in the jet stream near the West Coast.  This is happening while I write.  Parts of the San Francisco Bay area and Monterey have been soaked today.

These last two “storm seasons” have been the most boring I can remember (for a weather geek) for this reason.  Either upper-level ridging weakening storms over/west of us or a split jet stream sending energy south.  Of course last year the action suddenly picked up in early February with cold/stormy/snowy weather.  At this point, 2019-2020 storm season looks just like last year…so far.  I think we’ve seen ONE marginal high wind warning on the coastline in two months!  No storms in the Willamette Valley, no freezing rain, snow, or stretches of days with heavy rain/wind.  Cascade snow pack as of late December is tracking similar to those rough years 2014, 2013, & 2004.   About 3/4 of the typical snow pack we’d see on the ground around Mt. Hood is missing this year.



For a quick summary, head down to the next headline…

Here’s the scoop, note the 500 millibar map for tomorrow morning.  Ridging building in over us while that disturbance soaks parts of California.


New Year’s Day:  A cool trough is passing by as the flow turns westerly overhead.  Showers and lower snow levels mean some snow in the Cascades after the New Year’s Eve soaking.


All models are showing this as the beginning of a pattern change where a strong upper-level ridge develops out around 160W longitude; a preferred spot if you want cool/cold winter weather in the Pacific Northwest.  Take a look at the 10 day forecast from the GEM/ECMWF/GFS models.  Actually these are the ensembles from each of those models.  Big ridge south of Alaska and cold upper-level troughing over us.  Each model is a bit different, but the same idea and they all get to this pattern by days 10-15 out in time.  So theoretically we’re headed into a cold weather pattern beyond Friday and of course we can get low elevation snow out of this setup if things work out right.

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BUT, models keep pushing that change out in time.  For example, this morning’s run of the ECMWF has a temporary ridge popping up over us Friday.


Just two days ago it showed a very cold trough bringing snow down at least to 1,500′ for Friday


And farther ahead, for the middle of next week, the features are shifted farther east on current model runs compared to what we were seeing 1-3 days ago.  A ridge closer to us means the lack of  normal stormy weather would continue into early January (rainy/windy storms).  It also means Cascade snow gets shunted to the east too.  Just two days ago models were showing many feet of snow in the Cascades this coming Friday-Sunday.  Now we’re down to a foot or so.

So my concern is, for some reason, models still may not be catching onto the correct future placement of these features.  They are giving up on this persistent pattern we’ve seen since October.  This happened about six weeks ago too.  Remember in mid-November it suddenly looked like a very wet and cool period was ahead and we’d be done with the weak weather systems?  Rain for six weeks on the models?  I know this is hardcore weather geek stuff so I’ll summarize


  • New Year’s Eve will be wet, but not a soaker in the lowlands
  • New Year’s Eve WILL be a soaker in the Cascades…all rain up there
  • A Pacific cold front should drop snow levels down to at least 2,000′ or a little lower next weekend.
  • We MIGHT see a change to colder weather for NEXT week (6th-12th), but at this moment there’s no sign of a lowland snow “event” in the next 9 days.  That’s through Tuesday the 7th.

And by the way, Monday looks like another very nice day for late December…just partly cloudy.

For the skiers/snowboarders, here’s the Government Camp 7 Day forecast.  Should be some good snow Wednesday and then again next weekend.  Hopefully this will be enough to get Skibowl, Hoodoo, and Willamette Pass opened for the last few days of Christmas Vacation.

7 Day Forecast GOVT CAMP


Chief Meteorologist Mark Nelsen

66 Responses to Wet New Year’s Eve, Plus Big Weather Change POSSIBLE For Early 2020

  1. Andy says:

    Just checked out the 00Z run…more eye candy. I’m not biting on the bait yet. If it continues the trend, I might hop on.

  2. Mountain Man says:

    Sorry yeah I too like day dreaming of -15 850mb temps and I know you practically grew up on this blog so please don’t feel like I want to kill your buzz, I was just letting a few peeps know that there’s free information out there.

  3. Buff Gregg says:

    Smokin hot model runs, can I get a 12z?

  4. Jason Hougak says:

    Most fun of the blog and all ya guys feed is a buzz kill, will it happens not sure, maybe not in the lowlands but there’s always hope it will. Eye candy is what I’ve been waiting for all winter to see if something actually happens. Sure let been let down before but it is encouraging.

  5. Mountain Man says:

    I’m going to just say that, as most of you know, these beautiful gfs runs are serious cold outliners and ensomble averages only give foothill snow at best like they have been doing for days, just like when we had several warm outliner runs a few days ago. The operational runs are a nice trend, but look at the ensomble charts before getting on the train. Wetterzentrale is a good one for spaghetti charts.

  6. Registered Nerd says:

    Ok I’m going to get on the train. All aboard! I’m usually a weather blog stalker most of the year but when the models start teasing us like this I crawl out of the woodwork…

    Every time we’ve had real snow/cold over the last 10 years I’ve had to go in to work (medical field), this month I am off work FMLA and looking forward to enjoying a real snow and staying home….please please please!

  7. Scott Reeves says:

    Looks like Weather channel app is showing snow

  8. Evan -- Cedar Mill says:

    Two words: Eye. Candy.

    • Andy says:

      I agree…incredible cold in Canada and that cold coming down over Oregon. I also noticed the snow totals over the Cascades were incredible and about a foot of snow in the valley for the total run. Hopefully this trend continues…time will tell.

  9. Jason Hougak says:

    12Z GFS put 33” of snow in Seattle with Portland at 9, the 18Z put Seattle at 19” and Portland just under 12”. The Cascade look amazing.

  10. Jake in Gresham says:

    Well the GFS 18z was interesting. It bring cold air over the ocean a bit much on the 8th / 9th but calls for snow here in the valley. Then on the 11th an arctic front collides with a 980’s mb storm off the Olympic Peninsula.

    We’d see breezy warm South winds and rain but Vancouver, BC on the other hand…

    • Jake in Gresham says:

      Heh, I should have watched the rest of the run. It gets even more wild. The active front practically drops in Northern California. This would be an all out arctic outbreak for us. I call crap (Rockies are always under estimated) here but who knows.

      La la land but it’s getting there considering weather models have been hinting at something from the 5th (fairly heavy Cascade snow now locked in) onward since about 2 weeks ago.

    • Ken in Wood Village says:

      Interesting indeed. I skipped down to the end because I wanted to see what their outlook is for next week. They also are thinking about low elevation snow too. The models have been hinting about more of a North to NW flow which could bring snow levels to very low elevations. We’ll just have to keep watching the models to see if they keep up what they are showing.

      Thank you for the post 🙂

  11. Ken in Wood Village says:

    Just looked at the 06Z GFS run!! Full out artic outbreak starting around the 11th. Also looking at the 12Z GFS, it still shows the artic outbreak starting around the 11th. Could we be in for some actual winter weather?? We’ll see!!

    Now if only the GFS keeps showing this and I like to see the Euro come on board.

    Everyone needs to do their artic dance!! 🙂

    • Anonymous says:

      Usually little precipitation with arctic air don’t get that excited

      • rmlounsbury says:

        Not entirely true, often times with Arctic air you get BC Sliders that spin up and run down the coast line. Those can give you considerable snow.

        On the other side of that coin even without a BC Slider you still probably get a 1-2 day transition even that at least starts as snow.

    • Tantalizing, to be sure, but at this point it’s just one model and it’s in clown range.

      • Ken in Wood Village says:

        Actually, some of the other models are showing the same pattern.

      • Ken in Wood Village says:

        All the models are showing a OVER ALL PATTERN of NW to North flow. The Euro is showing it. The GEFS is showing it. The GEM is starting to show it too. The GFS is being a little aggressive with the cold tho. I’m not sure if the temps are going to happen but temps to the North have been running really cold (from -30 to as low as -50). It’s just a waiting game to see if the models will keep showing this for the next few days.

  12. Joshua Lake Oswego says:

    Just another warm predominantly dry evening. High res models handled epic rain shadowing beautifully. GFS, ECMWF, and GEM all big-time busteroo.

  13. Reeves says:

    I think we could see some snow by mid month

  14. Mr Realist says:

    Are we supposed to see a big change after new year’s????? Models sure don’t think so.

  15. Jason Hougak says:

    18Z another nice run. I hope the Mtns get buried.

  16. Roland Derksen says:

    Oh well, there’s always February if you want cold and snow! 🙂

  17. Yawn yawn yawn….Wake me up when winter gets here….

  18. Looks like I might get a windstorm on Friday. Weather.com has snowflakes towards the end of my 10-day forecast, but that’s well into clown range.

  19. Roland Derksen says:

    If the month of December had ended yesterday, I’d be proud to say i came very close to my estimated prediction of 7 inches of precipitation for my location. Unfortunately, the month has 31 days, and with today’s downpour we’re going to end up with at least 9 inches. And January appears to be starting off wet too- sure hope that drier cool spell that’s been discussed comes soon!

  20. Ken in Wood Village says:

    The 12Z GFS was very interesting close to the end of the run. I don’t think it will happen but it’s nice eye candy. Could be a artic outbreak if it verifies.

    • Jason Hougak says:

      The 12Z GFS was a great run. I like the consistency of building mountain/ foothill/ coast range snowpack. The run did put 13.9” of snow at PDX starting January 12th followed by colder northern flow with over running out over the Pacific.

      • Ken in Wood Village says:

        I agree. All the models are showing this type of pattern but it’s still a long ways off so we should get our hopes up. Hopefully it will show this pattern when we get to the goal of 5 to 8 days out. I’m waiting for the EPS to come out. It shows all the way out to 15 days and will give me a better idea on what could happen.

  21. W7ENK says:

    Interesting weather news out of Australia.


    I watched this happen outside San Bernardino once, back in August 2002 I think. A massive fire in the mountains built up a big cloud, which started spitting lightning, which started more fire, which built up another big cloud, which started spitting more lightning, which lit more fire, another big cloud, more lightning making more fire, and the whole thing started walking itself down off the mountains and across the valley. Backlit by the sunset, it was both fascinating and terrifying to watch!!

  22. WEATHERDAN says:

    53 days (2,21) until exhibition baseball. 69 days (3,8) until DST. If this Winter is a bust after then bring on Spring. I am sick and tired of day after day of cloudy and 48. I hope for some cold and snow soon. If not I want a few early Springlike days. Haven’t given up on Winter but I’m close. Peace and Happy New Year

    • Doug in LO says:

      +1 here, Dan, on the relentlessness of these moderately cold and dry days, one after the other after the other. After the other. The kind of “”winter” I had for decades living in Sacramento and moved here to get “”real seasons”. This winter, and last, are so reminiscent of NorCal that I am beginning to fear that this is what we are becoming. 26.85”” of rain for an entire year? Beyond sad.

      Doug in LO

      • Joshua Lake Oswego says:

        Our water year (beginning October 1st) is already about 7” below normal. Almost exactly 50% of normal. Yikes. The Douglas Firs and other native vegetation will only be able to take this for so long.

    • I agree with WeatherDan. The time between New Years and the start of the Cactus and Grapefruit leagues can be so dreary, If we can’t have snow can we speed up time until catchers and pitchers report?

  23. Tanis Leach says:

    Lets look at the seasonal prediction and how they are doing. Will be doing consensus/majority predictions, NOT my own, with one exception.

    Cascade snowfall: near average: not looking good, but still 3 months to go.
    Temps: near average: too early to tell. Most do Nov-March.
    Rain: slightly below average: remove slightly. (Note: I put 39 inches or 3 inches above average, don’t know what I was thinking. Probably mistakingly thought a wet September leads to a wet winter)
    Wind: Higher than normal chance of a 60mph valley event: While a stretch I personally would count the Thanksgiving bomb cyclone as one.
    Snow: big snow year. Best shot January (Febuary for Rod). Too early to tell. Ask me again on Jan 15th.

    Conclusions: Its safe to jump to the rain conclusion but not any other ones for a few more weeks.

  24. Mr Realist says:

    Put away your mittens BITCHES winter is over.

    • Tanis Leach says:


      Note below rule:
      3. NO PROFANITY:
      This is pretty obvious, but avoid being rude or taunting others too.

      Sorry to be that guy but I am not going to open the swear words can of worms.

  25. OLIVER WATSON says:

    12z gfs is showing cooler and wetter weather than last 3 runs. The back and forth continues.

  26. Paul D says:

    Summed up with a “YAWN” 😦

  27. Joshua Lake Oswego says:

    Prepare to not watch the radar again Tuesday afternoon into Wednesday unless you enjoy watching everywhere north, west, and east of you getting soaked while you get dripped on.

  28. ocpaul says:

    “And by the way, Monday looks like another very nice day for late December…just partly cloudy.”
    For me, a nice day for late December is cooold and snoooowy No putin lipstick on this pig.

  29. Mr Realist says:

    I hate to say I told you so 🤓🤓🤓🤓

  30. JohnD says:

    Glass half/glass half empty. Not sure right now. But mostly I’m looking around for the bar lady to fill ‘er up again.
    Anyway, Happy New Year!—Mark and All!

  31. Larry says:

    Snow chances are starting to dwindle on all models, especially on the ECMWF Ensemble. Cant say I didnt expect this to happen…

  32. Andy says:

    I am hoping for the change…but like Mark said we have been burned so many times this year. If we don’t see any change this month, maybe February will bring the goods or we have a dud of a winter.

  33. W7ENK says:

    Not gonna happen, nothing to see here, please move along…

    • I wouldn’t be quite that negative, but I’m definitely in “believe it when I see it” mode for model runs that far into the future.

      • W7ENK says:

        History says: Not gonna happen.

        The chances on this one are so remote at this point, and since historically the chances are always stacked against us, it’s a safe bet.

        It’s not going to happen. It might get colder, but we (Portland) won’t see any snow out of this. This is destined to be a “goose egg” (0) winter. Despite everyone else saying we’re overdue for a big Winter blast, we’re actually more overdue for a no-snow Winter in Portland.

        It’s not going to happen.

        • Larry says:

          Historically in Portland, we have seen a common pattern of a no (0) snow winters every 5 years, running since at least the 1980s. For example, 92-96 we’ve saw 4 consecutive winters with snow; 92-93 with 14.1 inches, and 95-96 with 8.7 inches. The next winter laid a big fat 0 for the total.
          There WAS a time when this pattern didn’t happen (98 to ’07) but recently this pattern has showed up again.

          Yes, it is possible we see an arctic outbreak this winter. I did some research, and research says Portland sees an arctic blast about every 5-8 years.

          To sum it all up, we are likely to see another bad winter here in Portland. We also may get an arctic blast, but it could be a few winters before we actually get it.

        • Tanis Leach says:

          I call it a wash. Why I’ve put my money on a big snow year with best chance January (looks like mid to end if it happens), comes from solar minimums which DOES affect our weather (Kyle Ditmer). The last arctic blast from Mark’s definition was 5 years ago in Feb 2014 (I will say 6 in 2 days). The return period is 3.5 years. The last no snow winter happened in 2014-15. Return period 4.5 years. Deficit: arctic blast: 2.4 years (to be exact), no snow: .5 years. Also back to solar minimums. Out of all the solar minimum years at the NWS site, only 1 (76-77) had a trace of snow or less. Most were decent snow years (6+ inches). I don’t know for sure, but I think that was an el nino winter.

          And for the record, you CAN get arctic blasts with minimal or no snow (ex: Dec 2013).

  34. 97015 says:

    Hmm. I like the possibility

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