Winter isn’t finished yet; colder days return in final days of January

3pm Monday…

We all know January as been very mild. Temperatures are running several degrees above average; the official climate station at PDX hasn’t even dropped below 32 degrees! That mild weather continues through Friday and probably Saturday too, but then we see a change in the last 4 days of the month.

For those with short attention spans…also known as TL;DR (too long, didn’t read):

Quick Summary

  • Mild weather continues through Saturday (the 28th). Weather likely won’t affect your life much the next 5 days. Continue with your normal daily lives
  • Cold air will likely arrive in the Portland metro area, and all parts of the region, Saturday night or Sunday.
  • That means high temperatures fall into the 30s in Portland for Sunday and probably stay that way next Monday. At this point we don’t see the REALLY cold stuff that appeared in December. Remember the afternoon high of 23 just 3 days before Christmas??? 35-39 would be much more reasonable, but still cold.
  • As the cold air arrives, will there be enough moisture around for snowfall? That IS a possibility Saturday night or Sunday morning and several of our models are producing that right over the metro area and points north (not so much south of Portland). Others say it’ll be too dry.
  • So the question “Will it snow at my house Saturday night?” is answered at this point by “that’s possible”.
  • NEXT week could be a busy weather week with cold air interacting with moisture to possibly produce snow. But models are all over the place that far out in time.
  • We will be in a cool period Sunday through at least the first few days of February, keep a close eye on the forecast. It’s time to pay attention again!

The Change Ahead

The pattern setting up is a classic one for cold & snow fanatics (yes, there really are people like that!). It doesn’t always produce snow, nor does it always send a really cold modified arctic airmass into the region. But when Pacific Northwest meteorologists see this setup, we watch closely!

A strong upper-level ridge is sitting over the far Eastern Pacific, just off the west coast of North America. It’ll be there through Thursday, blocking storms and keeping us dry; a nice change after almost 3 weeks of continuous rain. Here’s the view Wednesday; uneventful weather


But then a strong upper-level “shortwave” trough crosses over the top of the ridge and digs down the eastern side. By Friday, that first trough is over us. Showers, cloudy, but mild since flow is onshore


See #2 up above? That’s a 2nd and much colder trough digging down the back side of the ridge. So the ridge “retrogrades” or backs up to the west. And THAT opens up the door to the north. Cold air comes pouring south. By Sunday morning, that system is directly overhead (and heading south).


What you don’t see at the surface (this is up at 18,000 ft.) is cold/dry arctic air has surged south as well. It’s banked up against the east side of the Cascades at this point and pouring through the Columbia River Gorge. All models look about like this at 5,000′ Sunday morning; temperatures are in Celsius. BTW, everything is in Celsius on most weather maps. This means it’s about 10 degrees Fahrenheit up at Government Camp Sunday morning…brrr!


This setup is THE SETUP you want to get cold/snow into the region. Some moisture gets picked up by the cold air heading out over the ocean. Then a little extra lifting as that surface wedge of cold air pushes into the region. Sometimes we get NOTHING snow-wise out of this pattern as cold air arrives, other times maybe up to 2″. It depends on how that upper level trough digs south too. If it just moves by quickly and slightly east of where the Euro model shows it (above), we are typically just dry and a chilly east wind begins to blow. Since we’re still 5+ days out, it’s a real guess exactly how this turns out.

Models are in very good agreement on at least a short period of cold weather. GFS ensemble temperatures seem reasonable


The WRF-GFS meteogram shows enough moisture for snow sticking late Saturday evening and cold days Sunday through Tuesday. Saturday 4pm is highlighted with the yellow line. This model has been notoriously cold in the extended time range the past 2-3 winters. Maybe some sort of feedback from snow-covered ground. So let’s just assume it’ll be 5+ degrees warmer than what it shows.


And then notice about 1/2 of GFS ensemble members produce noticeable snow in Portland on the chart below. That’s a decent indicator that SOMETHING is up for this weekend. But what we aren’t seeing yet? MOST of those members producing snow; this situation is very much still evolving.


My final point is that we’ve probably got some sort of weather action on the way sometime between Saturday night and next week and it could involve more than one chance for snow. The two extreme possibilities I see right now:

1) We pick up 1-3″ of snow Saturday night, Portland is frozen all day Sunday and Monday, then a little more snow falls around Tuesday or Wednesday next week. 3-4 days of icy/cold stuff.

2) A chilly east wind arrives Saturday night, a few flurries fall, but doesn’t affect any of us. Temperatures only reach around 38-42 for a few days, then it’s back to milder/wetter the middle of next week and beyond. No real snow falls in Portland and it’s just a bit cold for a few days. Your life continues the same Sunday and into next week.

My gut feeling is it’ll be somewhere in between. But I’ll be at work all week; no scheduled time off until the end of February!

47 Responses to Winter isn’t finished yet; colder days return in final days of January

  1. tim says:

    18z gfs would be great for the Mt snowpack if it verifies but not likely.

  2. X (Aumsville OR) says:

    btw: Nov 1st (Or somewhere’s around there) was our only snowfall this winter up to this point. 1/2 inch from a cold front which it’s sad we didn’t get anymore.

  3. X (Aumsville OR) says:

    I know it sounds strange but you have to have artic air to actually have artic air. Just cause the models say it’s true doesn’t make it so.

  4. Ken in Wood Village says:

    I thought I would share this 🤗❄️

    • Andrew says:

      Thanks for sharing, Ken. Saturday evening is definitely worth watching though it seems likely it won’t be more than a light dusting for most of us. Discouraged to see the setup erode a bit in longterm with ridge moving back in over area. Hopefully we’ll see that retrograde again.

  5. tim says:

    Local news media in Seattle is really hypeing up the cold and snow nextweek people here are running around like chickens with there heads cut off here at the local hardware store freaking out.

  6. pgiorgio says:

    Cold air ☆☆☆☆
    Moisture ☆☆
    Wind ☆☆
    Fun ☆☆
    Future event fun potential (Mon-Fri) ☆☆☆

  7. Evan -- Cedar Mill says:

    Euro OP continues to trend warmer and drier. Typical.

  8. Evan -- Cedar Mill says:

    Looks like a quick-hitting dry blast at the moment.

    • Andrew says:

      I agree. There is clearly no undercutting pacific storm to produce a meaningful snow event. The set up to generate snow without such a system requires a very specific trajectory of arctic air intrusion out over the pacific to pick up enough moisture without generating too much warming. And even then such systems usually only produce an inch or two of snow. In our case it seems flurries are most likely scenario.

      If there is a silver lining, the general blocking pattern appears to persist for a while. while temps will moderate considering by end of next week, this isn’t like December when the arctic air was displaced by a warm system and a rapid transition to zonal flow. We may have another shot or two at an east wind event over next couple weeks if enough cold air can stay proximal to region. Nothing crazy compelling in models so far but that’s not the kind of thing that would show up this far out.

      • JohnD says:

        Like most of us, still hoping that temp/precip timing/trajectory will line up favorably come Sat. for an inch or so.
        I’m definitely not discounting that at this point in time.
        And—as you allude—the overall pattern worthy of daily monitoring for the foreseeable.

    • Scott Reeves says:

      Pray for some BC clippers

  9. Grizzly Bear says:

    Very cold weather predicted for here in North Central Idaho, the forecast for early next week in Kamiah, ID is down near 0 degrees at night. This forecast is from NWS:

    Sunday Partly sunny, with a high near 24.
    Sunday Night Partly cloudy, with a low around 0.
    Monday Mostly sunny, with a high near 19.
    Monday Night Mostly cloudy, with a low around 0

    We might get a couple of inches of snow as the Arctic front passes.

  10. Ken in Wood Village says:

    We should always look at the Ensembles 😉 the Euro really wants to give us the cold air. There is a little moisture when we actually have the cold air in place. It’s not a lot but we’ll see.

  11. Andrew says:

    Michael Snyder on his Pac NW Weather Watch really doesn’t seem to like the setup for snow. He did however note that the pattern wants to persist for a while so we may have other opportunities. I’m not suggesting that there is no chance for snow over next 7-10 days, but Snyder really knows his stuff and his lack of bullishness on snow potential is telling. Of course, a lot can change in models over next few days, and he does his video updates daily so much more to come.

    • Doinko - Bethany says:

      Euro gives a few inches to PDX before going very cold, 850s down to -15c. GEM is even colder. I’m liking the trends for cold so far

  12. Doinko - Bethany says:

    00z GEM is extremely cold, 850s down to -18c over PDX. 12z Euro was very cold too (-15c 850s) so I wonder if it’ll stay cold like that. GFS is easily the warmest

  13. Ken in Wood Village says:

    After the problems with the Euro models. The EPS model has come out. The Ensembles look really good for cold air but not sure if we will get moisture with the cold. If we do, it will be snow 🤗❄️

  14. WEATHERDAN says:

    Sunny and 39 in Salem at 2:00PM. Had dense fog this morning but glorious sunshine this afternoon. It’s looking better and better that we will get some cold and snow in here next week. Maybe 1-3 inches if we’re lucky, <1 if we are not. Even cold sunshine is better than day after day of cloudy drippy 48 degree weather. Sunset tonight is 5:09PM. Baseball season isn’t far off. Go Dodgers. Peace.

  15. Andrew says:

    Ensembles seem to be trending colder but not seeing particularly promising snow signals across the member range as a whole. I personally would welcome a lighter snow event via a northerly flow with modified arctic air pulling in moisture from ocean, than a potentially bigger event that involves an over run of warm air and brings ice and/or a quick warm up into play.

  16. Ken in Wood Village says:

    Looks like there is something wrong with the 12Z Euro. There isn’t any data coming out 😞

  17. Roland Derksen says:

    I’m looking forward to the cold (or fairly cold anyway) and dry conditions forecasted for the coming weekend. In the meantime, however, we have to put up with this dreary, drizzly weather today, and the next few days.

  18. j nelson nails says:

    Is agriculture looking at varieties with lower water needs and/or higher temp toleranc? Our glaciers are melting and water abundance is going to be a concern.

  19. Ken in Wood Village says:

    The operational run may look a little different for the Euro last night, the ensembles still look good for colder air to come into our area by the weekend.

    Not sure about snow tho. This situation maybe where we will see it the day of the event. It also could be where the models show it and we get the goods. It’s still a little to far out to really pin point what’s going to happen regarding the snow and how much we get.

    I wouldn’t mind what the GFS showed last night…lol 🤗❄️

    • Ken in Wood Village says:

      Not sure why my reply didn’t post.

      This is the picture I wanted to post instead of the one you see above.

  20. Ken in Wood Village says:

    Well, it was nice while it lasted 😭😭😭😭😭

  21. Tanis Leach says:

    To calm everyone down from the GFS down. Remember, its the GFS. I’m not on the train yet myself. There is definitely bust potential since we’re still beyond 3 days out.

    • Doinko - Bethany says:

      GFS was pretty ridiculous. Huge snow event with the arctic front, then some more light snow, then another huge snowstorm and then a temp of -17 degrees in Salem.

      The better models look nicer tonight which is nice to see. GEM looks very cold

      • Ken in Wood Village says:

        I will admit, the 00Z GFS is amazing but we need to see what the Euro shows 🤗❄️

    • portblazerfan22 says:

      The cold is looking better than even yesterday. Models having problems figuring out what to do with the sliders.

  22. Evan -- Cedar Mill says:

    00z GFS at face value is absolutely incredible. Won’t happen though.

  23. ocpaul says:

    Call me a ‘cold and snow maniac’. I wear it as a badge of honor.

  24. Doinko - Bethany says:

    Check out the Euro ensembles, a good cluster of really cold members

  25. Ken in Wood Village says:

    Thanks for the update Mark 😀 February has been a great month for snow too. I remember living in Tigard in 2014 and having about a foot of snow. Winter is far from over 🤗❄️

  26. tim says:

    Winters last gasp.

    • Jim says:

      Hey Tim tell us how freaking hot it’s gonna be this summer. That’s your specialty

      • tim says:

        Extreme heat is very likely it’s been the trend now for nearly ten years and there’s no reason to believe that trend will end anytime soon years, climate change is real and unfortunately mets like cliff mass and others are in denial. At least weatherdan is on board he also believes were in for another hot summer so I’m not the only one, how come you don’t pick him as well?.

        • tim says:

          Heat related deaths will be more common unfortunately in western Wa and Oregon especially with more the half of the population without AC units in theses cities something needs to be done soon.

        • Jim says:

          Weatherdan doesn’t seem obsessed with hot weather like you. Can’t we just discuss current weather while it’s happening? That’s what I look for on here

        • tim says:


        • Tanis Leach says:

          9 summers in a row at or above the climate change exponential trendcurve is not usual, a cold summer is going to happen at some point, but it won’t be 1950s cold.

        • Roland Derksen says:

          I don’t know much about 1950’s summers. I grew up in the decades following the 1950’s and we had some cool summers in the 70’s and 80’s here. I don’t predict summers like those decades, but perhaps a summer like 2011 or some other fairly similar summer could( and that’s only a small possibility) happen. However, I’m not thinking about it much yet.

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