A Cold and Dry December

It’s pretty obvious that we won’t get much rain in the next 5 days.  A few showers are possible tomorrow afternoon and/or Monday/Tuesday.  But that’s it.  As of now, we’re running in 2nd place for December precipitation here in Portland.  1976-’77 was drier.  A chilly month too!  As of now it’s the coldest month in 4 years (Dec 2009 was slightly colder), and those two are the coldest since 1990.  I was surprised some other months in the past 10-15 years haven’t been colder, but all those other years we saw a warmer spell at some point during the month.  This year it was the arctic blast, then lots of inversion weather with very few days at/above 50 degrees to balance out the temps.MarkRain_DecemberFactsToday was a classic winter inversion day in our region…50s and 60s in the mountains  and mainly 30s in the western valleys under the fog and clouds.


The weak system tomorrow probably won’t do much to change our weather.  Without significant offshore flow (easterly Gorge wind), it’s tough to keep the fog and low clouds away here in the metro area.  Still, we had just enough easterly drift (overhead, not at the surface) to clear out most of Multnomah County for a 2nd day.  Here’s a sat pic at 1pm:


Notice everyone else below 1,000′ or so is stuck in the muck between the Coast and Cascade Ranges.

Long range maps don’t show any dramatic changes to our weather through at least 10 days.  The GFS has hinted (for all of 2 runs) the ridge might try to push farther offshore, possibly setting us up for colder weather and/or better chance for mountain snow.  But it also did that about two weeks ago, showing a cold and wintry pattern between Christmas and New Year’s.  We see now how that turned out…

So please continue to enjoy the fog, sun, and even a few sprinkles!

Chief Meteorologist Mark Nelsen


99 Responses to A Cold and Dry December

  1. NRCS Hydrologist says:

    FYI, NRCS stands for Natural Resrouces Conservation Service. They are part of the USDA (US Department of Agriculture) and maintain the SNOTEL network which consists of over 800 high elevation climate stations that monitor snowpack in the Western US and Alaska.

  2. Wooly Bully says:

    I have to admit, 12z looks good. And, yet, “A Ridge Runs Through It”, which makes me think the precip model is wacked.

  3. Kenny says:

    SCORE, SCORE, SCORE, SCORE! The new 00z GFS brings the arctic air with tons of moisture! SCORE!!!!!!!!!!

  4. Lurkyloo says:

    Honestly, at this point I would rather take all the la-la land forecasts, wishcasting, and even JJ’s jealousy-inducing reports from San Antone, as opposed to a set-in-stone forecast of eternal air stagnation, inversion and overall gloom …

  5. Sapo says:

    18z GFS shows some pretty heavy snowfall amounts in the valley January 7-9th. At least it’s looking like we could get some cold weather and the mountains some snow.

  6. Timmy_Supercell (Klamath Falls @ 4200') says:

    GFS shows some moisture arriving 2nd week of Jan, some of which looks like snow but mostly rain. Still not good for the cascades down here. Of course it being this many days out, those low temperature may all go down to below freezing.

  7. StormKingesque scenario depicted in fantasyland by the 18z GFS. That’s OK, all will be forgiven this winter if that verified:)

  8. Model Rider says:

    Its pretty obvious well get a major change next week per gfs even after 18z run. How much and what who knows. Come on Euro 00z. Hope its another run like last nights.

  9. Wooly Bully says:

    I don’t see a whole lot of precip out of the 12gfs and I don’t see the death ridge going anywhere — well, besides shifting in her seat perhaps. We’ll probably get some new snow in the next 7-14 days, but I don’t see any indication of a game changer out there. If that thing stays around, there is no winter this year.

  10. Rob - Southeast Portland says:

    12z EURO full run
    This is exactly why we don’t get too excited too soon. Not a very good run. Ridge pops up favorably initially, but slides well to the east. It could be just a bad run in the mix which we always see a few of them when we’re 7 days out before things are nailed down. Or?…. 00z in 11 hours 52 minutes

  11. Rob - Southeast Portland says:

    Still a long ways to go… The ridge could just as easily pop up initially very favorably near 150 W, but slide east too soon leading to a glancing blow.

  12. paulbeugene says:

    Looking at model runs this morning, am cautiously optimistic that we will have change toward a cool to cold weather pattern as we head past the first weekend in January.
    Models want to build 500mb heights over Alaska to set up trough over NW USA.
    I don’t see this as A) a heavy precip producer or B) an arctic blast.
    The Euro did show a pretty hefty block with heights over 564dm over AK..so maybe things will turn colder than it looks to me now.
    Seems more like a climatologically normal pattern for early January with snow down to Gov Camp, Welches, even Sandy.
    Don’t get me started on schools closing during “severe” weather. We might be headed to another period of “severe” weather as school starts up again.

    • Rob - Southeast Portland says:

      12z GFS great 500mb pattern. I think if the 500mb pattern sets up as the GFS/EURO shows we will be quite a bit colder and will see future runs turn colder yet. I would say that is a guarantee in fact.

      12z GFS Ensembles. A bit of improvement with the mean. A lot of members clustered around -5c to -7c.

      Still a ways to go, but encouraging at this point.

    • MasterNate says:

      I don’t really start getting excited until the both of you chime in. Good to see you again. Lets get this party started! 🙂

  13. SW says:

    I’m also glad your back Rob, I appreciate your input and enjoy the reading!

  14. JohnD says:

    Thanks Rob. You rock. PLEASE keep it up!

  15. Kirk(Sandpoint Idaho) says:

    Glad your back Rob!

  16. schmit44 says:

    12/27/2013 Oregon (All) Temperature Summary

    High:59 at VILLAGE CREEK(1565 ft)
    Low: 45 at CW8449 Charlesto(322 ft)

    High:14 at NYSSA(2172 ft)
    Low: 1 at NPOWDR (3212 ft )

    Largest Diurnal Change: 37 degrees
    COLGATE (58/21 ) (3231 ft )
    CW1010 Sisters (56/19) (3189 ft)

    Heaviest Rainfall:
    0.08″ at DW9126 Brightwoo(1336ft)
    0.08″ at LOG CREEK(2800ft)

  17. Rob - Southeast Portland says:

    00z NCEP/NWS Pacific Surface Analysis & 28km Water Vapor Imagery

    Me thinks that massive 952mb low heading up towards Kamchatka Peninsula is the major game changer we need to set the ridge/block up near 150-155 W and deliver the goods shortly thereafter.

  18. Marcustheweathernut says:

    00z euro looking real nice !!!! 🙂

    • Rob - Southeast Portland says:

      00z EURO 500mb pattern develops favorably after day 6. Very similar to 00z GFS op, hmmm maybe the Ensemble is the outlier just like it was initially during our last Arctic blast in early December…. Sound familiar? I like how the PV is shifting southwest towards us too. COULD be a major prolonged event. COULD be that is.

    • boydo3 N Albany says:

      Snow in the mtns. As per my earlier (8 ball outlook) …
      “The GFS is locked into a pattern change in a week or so. I’m thinking the euro will begin to as well. Not convinced about a snowy pattern down low but definitely wetter with snow in the mtns.”
      Lets kick this ugly ridge the hell outta here!

  19. Rob - Southeast Portland says:

    Merry Christmas

    00z GFS wasn’t bad, fairly promising in fact. 500mb pattern sets up after day 7. Rex Block H/L axis 160 W is always nice. Then around day 9-10 with the ridge amplifying well up through western Alaska positive tilt looks real encouraging and the Great Lakes/Eastern US ridge helps too. There is nothing to complain about with this run. If we see the 500mb pattern setup like this the cold air will come.

    Onto 00z EURO in 1 hour 53 minutes

    • Rob - Southeast Portland says:

      Actually things set up after Day 6. Let’s see what the Ensemble shows, and 00z EURO later…. Hard to tell what kind of trend we’re seeing now. Is it for an arctic blast? or for more ridging at 130-140 W?….

  20. Marcustheweathernut says:

    00z gfs Arctic blast jan 8-13!!!

    • Model Rider says:

      I see a little bit of hope off the 00z. Looking good. Several runs in a row now. But this is the best setup on the models so far. Deep trough from the arctic with maybe westerlies undercutting which would produce snow this time around. We shall see if this comes to fruition. Timing has moved up as well with this run I might add too.

    • Marcustheweathernut says:

      Choo-choo chug chug chug chug!!!!!

    • pappoose in scappoose says:

  21. Jason Hougak says:

    Doldrums… HELP!!!

  22. Marcustheweathernut says:

    18z = snow storm for Pdx!!!!!!!! Only 10 + days out!!!!! :} Come and ride the train and ride it!!!!!!

  23. W7ENK says:


  24. Timmy_Supercell (Klamath Falls @ 4200') says:

    Much of SW Oregon including this area, is seeing the all time record driest year. Klamath Falls has seen 5.36″ of precipitation since Jan 1, beating previous record by nearly an inch.

    • Dave in South Salem (500') says:

      Do you get sunshine there during the day in this pattern? I’m thinking of going that way towards California. I’ve heard Shasta is bone dry…

    • Timmy_Supercell (Klamath Falls @ 4200') says:

      Miraculously its been overcast here last few days. Typically it is 100% clear if its not snowing. They say there’s 300 days of sunshine per year! 😉

  25. poolsidemike says:

    i’m hoping that maybe we can squeeze out a tiny little flake or two of “snog” (snow flurry out of the fog bank!) if any moisture makes it in!

    • David B. says:

      There’s been some light rain up here in western Washington today. Not much to write home about. Fog and inversion should return for the weekend.

    • pappoose in scappoose says:

      I really like snizzle!

      Posted by Wanda J under Family, Knitting | Tags: Handknit Sweater, Ocean, Snizzle |

      Snizzle. The fog had been thick from our place through the valley to Salem where suddenly everything looked snow covered. We were truly puzzled, a micro-climate of snow in a small three-four block area near the heart of Salem?
      The evening weather report talked about Snizzle – yes, there is such a word, as well as snizzling. It happens when the fog is so thick with moisture that it has to release it and it becomes a dense drizzle (oh, so common in Oregon!). When the temperature is low enough the drizzle actually turns to a form of snow: snizzle.

    • pappoose in scappoose says:

      What I really mean to say is lets see how much snizzle we can gather! Hahaah!

    • pappoose in scappoose says:

      Right there with you poolsidemike, I’ll be counting/naming!

  26. Wooly Bully says:

    It’s Groundhog Day, yet again.
    So darn depressing out there. .
    Wonder what the weather is like in French Polynesia right now.

    • Wooly Bully says:

      To Ms. Death Ridge of hades:

      “Set me free, why don’t you babe?
      get out my life, why don’t you babe?
      ’cause you don’t really love me
      you just keep me hanging on

      Why do you keep a-comin’ around
      playing with my heart
      why don’t you get out of my life
      and let me make a brand new start
      let me get over you
      the way you’ve gotten over me, yeah

      Set me free, why don’t you babe?
      get out my life, why don’t you babe?
      ’cause you don’t really love me
      you just keep me hanging on
      now you don’t really need me
      you just keep me hanging on”

    • clyde says:

      Just curious, why do you think it’s depressing if it’s not raining? This weather pattern allows for all kinds of outdoor activity.

    • Wooly Bully says:

      I wouldn’t recommend a whole lot of outdoor activity under current air quality conditions. (Unless you’re training for the Beijing Olympics).

    • Wooly Bully says:

      BTW, just curious why you live in the Pacific Northwest if you don’t like storms in December?!?!?

  27. Marcustheweathernut says:

    12z euro not in agreement with gfs!!!!! Shows death ridge hanging on!!!!!

  28. Sapo says:

    12z GFS Ensembles looking chilly for January 8-9th. It’s pretty spread out, but lots of members are below -2c. A few are even showing -8c, -9c, -10c temps. It’s pretty far out but the trend has been there, so hopefully it will develop into something as we approach those days.

  29. David B. says:

    Last night was just odd up here. The fog actually burned off for us so we got a nice sunset followed by the stars coming out. Then… Wham! Super thick fog develops in less than an hour. Visibilities must have been 1/16th a mile or less at times. Then a few hours BEFORE sunrise, the fog dissipates.

    Probably an advection fog: first, the island underwent radiational cooling after the Sun went down, then a light breeze came up and transported some warmer moister air from Puget Sound over the cold land causing the sudden dense fog. Then the breeze got a bit stronger and dissipated the fog.

  30. JJ78259 says:

    55 degrees and raining here in San Antonio. 68 and Sunny for the week end though. Light rain nothing heavy feels like a spring day in Milwaukie. I could use some Texas heat soon it has been cool this winter. We should be getting a blast of humid warmth here shortly can’t wait!

  31. DCZ (Hillsboro) says:

    Intel effect in Hillsboro this morning. Along Brookwood Parkway at 6 a.m. there is about 1/4″ of white stuff on the grass and trees. At one point near the library it looked like we had experienced a real snow event with so much clinging to all the branches. ‘Twas beautiful really.

  32. I hiked Devil’s Rest yesterday in the gorge. You can start at either Multnomah or Wahkeena Falls. Either way, it was cold and icy on parts of the trail below about 1,500′. Above that it was warm and calm Felt like the mid 50s. I was in shorts in a t-shirt until reaching that same level on the way down where the coat went on.

  33. paulbeugene says:

    I love the GFS 6z. Nice way to get mind off of daughter’s vomit I just cleaned up 30 min ago. Lysol works great. Too bad can’t spray it on computer screens when horrible runs pop up

  34. Wooly Bully says:

    Don’t believe that GFS for a minute. It’s been close to useless ever since that high ridge showed up. The long term trend is waxing drought — just have one look at the 90 day precip. anomaly. http://water.weather.gov/precip/

    Also, sudden spike in equilateral ocean temps off Peru have me thinking about ole El Nino.

  35. schmit44 says:

    12/26/2013 Oregon (All) Temperature Summary

    High:72 at BALD KNOB(3630 ft) & SIGNAL TREE(3294 ft)
    Low: 55 at SILVER BUTTE(3973 ft)

    High:18 at NYSSA(2172 ft)
    Low: 2 at HEREFORD (3599 ft )

    Largest Diurnal Change: 45 degrees
    COFFEE POT FLAT (65/20 ) (5206 ft )

  36. Ben T says:

    At least there’s something to maybe keep an eye on 🙂

  37. BoringOregon says:

    Maybe time to issue another BoringWeatherAlert!!!!

  38. boydo3 N Albany says:

    Ride with the GFS! Ride baby ride!!

  39. Heatblizzard says:

    Or perhaps The Drop where it plunges and stays cold from March thru June just in time for July where it gets unusually humid all points south of Portland.

  40. Heatblizzard says:

    At least Mark’s updates answers my question. No easterlies anytime in the near future. Dagnammit. Wanna bet we are going to have a roller coaster spring temp wise?

    How about The Screamer?

  41. Dave in SW PDX (235') says:

    Thanks for the update, Mark. Only 1.15″ of precip so far this month at my place, very dry.

  42. MasterNate says:

    GFS looking better 2nd week of January.

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