Mild & Dry November; A Big Change Possible For Thanksgiving Week

7pm Monday…

What a November it has been, plenty of sunshine and warm temperatures at times.  The entire western USA has been VERY dry since late October; most areas west of the Rockies are under 50% of average.

anomimage

Of course temperatures have been mild/warm too.

conus_mtd_t2max_anom_2019

The only part of the Pacific Northwest a bit cooler than average is the Columbia Basin.  This November is tracking similar to one year ago.

Mark November Rain

Although last year the mild/dryish conditions continued through the end of January!  We’ll hope that’s not the case again this year.

A weak weather system is moving through tonight, we’ll probably end up with a quarter inch of rain or so.  A few inches snow fall up at the ski resorts too.  But this is a one-shot deal.  It’s back to dry tomorrow midday all the way through Saturday.  Expect a gusty east wind to return Wednesday PM and Thursday as well, but nothing crazy strong.

To summarize:  Not much happening weather-wise through at least Saturday.

Why so dry & mild?  Again we have persistent upper-level ridging in the atmosphere.  It’s either shredding storms apart as they move toward the West Coast, or shunting them to the north.  The result is mild temps and not much rain.  Here’s Thursday’s forecast from the ECMWF, showing the warm colors (above normal heights) again over our area.

ecm_thurs

Same thing Saturday, although the ridging is flattening quite a bit.  Something appears to be changing

ecm_sat

The upper-level ridging wants to push westward out over the eastern Pacific.  By Monday a chilly upper-level trough has dropped over us and into the central USA.  We should see a bit more mountain snow either Sunday or Monday.  Each model and model run is a bit different since we’re talking 7 days out.

ecm_mon_25th

Looking ahead to Day #9 (Thanksgiving Day!), all three main models show there has been a change to cool upper-level troughing over the Pacific Northwest.  That’s quite a change!  The ECMWF ensembles (images below are all ensemble averages, not a single model run) seem to be a bit hesitant making a big change.  Notice it wants to hang onto the ridging a bit more.  Not sure what to think about that.

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What does this mean?

  1. There may be a significant change in our weather beginning Sunday.  We may actually go back to normal!
  2. That would mean snow levels down below the passes, significant mountain snow, and valley rain at times
  3. Thanksgiving skiing is a possibility in this setup.  As I mentioned, each model run is different.  Check out snow forecast graphics from the Canadian, Euro, & American models.  They show total snow now through Thanksgiving Day.  All show at least a foot of snow, some much more.  Ignore the little bit of snow over the metro area.  That’s a graphical contouring issue.

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I did have a brief panic last night when the ECMWF showed a snowstorm over the Portland Metro area the day before Thanksgiving.  That’s another reason to stick to “ensemble forecasting”.  It was one of only a handful of the 51 members bringing snow showers into the lowlands.  It is gone in today’s run.  But it IS time to think about winter storms/snow/ice/wind/flooding. These three months from mid-November to mid-February are “action time” west of the Cascades.

Winter Months Explainer 2017

Here’s your Mt. Hood ski area forecast.  Expect some snow tomorrow, it’ll melt, but then a few more inches around Sunday/Monday.

7 Day Forecast GOVT CAMP

Chief Meteorologist Mark Nelsen

64 Responses to Mild & Dry November; A Big Change Possible For Thanksgiving Week

  1. JohnD says:

    Soooo great you’re in here Rob!

  2. Jake in Gresham says:

    East side of Oregon is going transition quick based off of current forecasts.

    It’s saying 50’s for Bend and 20’s at night, Monday then goes to 40’s for a high and then Tuesday they go to 30’s with a forecast of 3 inches of snow. Teens for nights and another inch Wednesday,Thursday another inch and more Friday.

    So regarding snow cover down to mid-East Oregon to keep the Columbia River Basin cool it looks very solid.

  3. Jason Hougak says:

    Exciting to say the least especially with Thanksgiving next week.

  4. Solid improvements on the 18z GEFS. PDX mean temp down to -5c with a cluster of members -5c to -9c. Yakima ensembles shows good support for backdoor cold possibly a modified blast. Think Cold and SNOW!!!! C’MON!!!!

    00z GFS in 1 hours 55 minutes

  5. Winter Enthusiast says:

    It sure feels like the weather is changing. Cold NE breeze. Hope next week gets interesting!

  6. Winter Enthusiasts says:

    It sure feels like the weather is changing. Cold NE breeze. Hope next week gets interesting!

  7. Mr Realist says:

    I bet the 18Z GFS is giving a few people in here a true forgasam😂😂

  8. Jake in Gresham says:

    Welp, hunting didn’t yield any elk in the southern coast range and was overall a rough trip for only my third time out there (I hit a deer on the way back).

    Lots of plant life taking advantage of the weather (it was mild and very wet). Tons of fungi, lots of deer, quail and one turkey. Also spooked a bear (sure spooked us!).

    Glad to see things flipped here in enthusiasm.

  9. Roland Derksen says:

    Beautiful sunny day here, and we’ll likely see the temperature dip just below freezing tonight.

  10. Tanis Leach says:

    18z GFS is looking FUN. Snowstorm on Black friday. Wednsday storm is now in Cali though.

  11. Donn in Deer Island says:

    What time it gonna snow, Boss?

  12. I just reviewed all 12z Operational Runs, GEFS, CMCE and EPS. Main take away. Blocking regime becoming more likely and seems models are also trending to want to build a southeast ridge around Day 7-8. Bitter air seems readily available on our side of the pole with a huge reservoir of arctic air nearly vodka cold over the arctic regions down into Yukon, Northwest Territories, British Columbia, Alberta. 12z GFS was a dream. Very cold PDX/GORGE with modified arctic air entrenched for seemingly forever with brutal east winds. GEFS a bit colder, some colder members, but 500mb not quite there with a lack of a ridge merger. 12z GEM similar, but the ridge merger and ultimate block placement is a touch further west than we want it. The CMCE unlike the GEFS now shows a full ridge merger and when that occurs a lot of possibilities for a cold or perhaps very cold pattern is now on the table.

    EURO operational was cold nearly delivering an arctic blast and the pattern Day 8-10 shows persistent blocking. 12z EPS Day Improvement noted again. Now showing full ridge merger a touch too far west, but not there yet in terms of amplification/orientation of tilt. Block, positive anomaly in the sweet spot and signs of a southeast ridge. We have a long, long ways to go, but this is looking quite promising. The main key and ultimate most important piece of the puzzle is the Offshore ridge/Aleutian ridge merger at Day 4 to 4.5 must take place or else we end up chilly somewhat, but no amplification and thus not able to tap into the arctic air to our north. Day 4 to 5 is everything right now. Onto 18z and of course the more vital 00z runs this evening. Think Cold and SNOW!!!! C’MON!!!!

  13. rmlounsbury says:

    I suppose we have finally reached model riding season. The GFS 06Z Op is fun.

  14. Jason Hougak says:

    Remember back in Sept. and Oct. when the roof came crashing down… it’s about to happen again. Patterns repeat themselves.

  15. On tonight’s 00z GFS, EURO Day 3-7 I haven’t seen that solid of agreement since the amazing December 2008 Model Performance where they agreed a staggering 8 days out and every run after showed rock solid consistency. 00z EPS BIG improvements. Not arctic cold. Not yet. Overall 500mb drastically better with a stronger block and positive anomaly persisting around the 150-160 W sweet spot with also a bit of a southeast ridge trying to build. We need better amplification and we’ll turn cold to possibly major league cold. I want to pull the trigger with my “Colder runs ahead! MBG Money Back Guarantee!” but not just yet….

    • Mr Realist says:

      Not happening, one run that is way out to lunch. Maybe push refresh and think cold and snow?????? Enjoy the boring winter.

    • Andy says:

      I agree…we are definitely trending toward a more active or exciting weather trend. Some models are showing well below temps trending at the end of the month and early December. If this trend continues “Lets pull the trigger”….

      • Larry says:

        I’m gonna wait on pulling the trigger until at least tomorrow. Last winter has hurt my trust in weather models showing cold and snow.
        Mark is right, stick to ensemble forecasting!!

        • Mr Realist says:

          Ensemble is not in agreement on cold lol.

        • Larry says:

          Exactly

        • I’m going to wait until it gets within 5 days and the models are still basically sticking to the same story. Been disappointed too many times in the past. What is encouraging is that there is no longer any model consistency to a death ridge with no end in sight (and actually the general overall pattern is pretty good).

        • Actually last February proved the point I just made. I remember surprisingly good model consistency showing the Seattle area getting buried (to the point that it was surreal, given the amounts forecast), and not so much consistency showing Portland getting much snow.

          A few model outliers that show your area getting buried don’t count for much; such things happen every winter.

    • Ken in Wood Village says:

      I don’t think I have ever seen a complete 180 on how the models switched to having a strong Low-with heavy rain and wind-to having a modified arctic outbreak. The GFS (00Z, 06Z and now the 12Z) is showing cold and snowy weather.

      The 00Z Euro did the same thing the GFS did. I’m now waiting on the 12Z Euro to see if it’s going to keep what it showed last night or change back to what it was a day ago.

      All I know is this pattern is what we kept seeing during the summer and early fall season.

      We shall see if this will be a trend and if so….we could be seeing snow early in the Portland area.

  16. 00z euro ensemble trending colder w 🦃 winter potential

  17. Kyleb_b says:

    New euro shows snow in Eugene next week

  18. Tanis Leach says:

    GFS 0z has a nice 988 mb low coming in, but coming south into Eugene, around the day before Thanksgiving. Hope it holds (kind of, don’t want my walking boot to get wet). Also snow level is 2000 feet at that time by the looks of things with that.

    • Tanis Leach says:

      Add an dry arctic blast to follow. Again, if it holds. Hope that does.

    • Ken in Wood Village says:

      I’m not going with the GFS. It’s been going back and forth for the past day on were to put the Low. The GEM and the Euro have been very consistent on a Low going to the North which would bring strong winds and a lot of rain. At this point, I’m going with those two models. We’ll know more by Friday or Saturday.

  19. JohnD says:

    Every single year there is a buzz kill, piece of…whatever…who somehow enjoys infusing negativism on what most of us just are trying to have fun with–e.g. Interesting and exciting weather.
    He/she reinvents their name. Same person. Pretty sure.
    Whatever I guess, if that’s all they have to do in their miserable life.
    Most of us are just doing it for the hobby passion.

    • Mr Realist says:

      I totally agree with you, we just want people in here to be responsible and realize we don’t like in the NE. Its not going to snow or be another ice age, fact is we are trending warmer. Happy Holidays!!!!!!

  20. W7ENK says:

    Was surprised to wake up to a half an inch of rain in my gauge since last night. Yesterday’s evening forecast consensus across most all mets was that it would be clearing off and drying out overnight, but that obviously didn’t happen.

  21. Mr Realist says:

    It is amazing how we are talking about how exciting it is that it rained in mid November lol. I can’t wait for everyone to be giddy about a lie of 32 in mid January 😉😉

  22. MasterNate says:

    First time in a long time the intense rain awoke me. Now lets get on with winter.

  23. Joshua Lake Oswego says:

    This narrow rain band is what we needed! First soaking in about a month.

  24. Larry says:

    Ive been watching that possible Thanksgiving snow set up for a few days (we’ll just call it cold rain for now).

    My question is whether the ECMWF current forecast stays consistent moving closer to Thanksgiving, or if it trends closer to the GFS and GEM models.

    Thanks Mark!

  25. Mr Realist says:

    Here comes winter rain for everyone!!

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