A Bit More Weather Action Ahead

Whew…it has been a SLOW December for weather geeks like me.  Different weatherwise than last December, but just as slow.  Last year at this time we had an upper level ridge overhead through much of the month, giving us cold valleys with nights well down into the 20s.  This time a ridge is farther offshore, letting weak systems move in from the northwest.  I made these two graphics today, since so many people ask me whether they should put the snow tires or studs on yet.  Wayne Garcia says he never bothered last year and was just fine.  It probably helped that he doesn’t have to drive in the mornings.  In fact I never once had to drive on snow on the way TO work last winter (once I was down to the freeway).  We haven’t had a daytime snow event in the metro area almost 3 years!  This is what I showed on TV tonight:



By the way, I’m sure not endorsing the use of studs considering all the damage they cause.  But you sure can’t beat the traction they provide.  And as long as they are legal some of you/us are going to use them and that’s reality.

Long range maps don’t show much change the next few days, but the ridge then appears to break down this weekend and beyond.  Models are in some disagreement as to what pattern evolves.  In general, it appears to be a bit cooler than average Friday through the middle of next week; note the 12z ECMWF and 00z GFS ensemble charts both showing 850mb temps a bit below average through that time:



I notice that neither model shows any sort of cold arctic air, even among the ensembles.  But they both show -5 to -7 850mb temps possible this weekend or early next week.  When we get down to -7 is when we get excited about hilltop snow (1,000′ or below) behind cold fronts.  There appears to be quite a bit of mountain snow Friday through the middle of next week too; possibly the best of the season so far.

Chief Meteorologist Mark Nelsen

128 Responses to A Bit More Weather Action Ahead

  1. paulbeugene says:

    Took a little post-dinner break at the computer to look at the Euro and GFS models…trend is for polar jet to be far the north…over Alaska, far N Canada while two mid latitude upper lows develop, one over the eastern USA…and one off the west coast…with some sort of spine of a ridge just E of rockies. I read on some other blog that this is the Pam Andersen pattern…she must have been some meteorologist at ? Penn St or Florida St that discovered this pattern.

    Regardless of whom this pattern is named after…looking back at CPC super analog years….it does not appear that we will be prone to arctic blasts for 2-3 weeks…the soonest occurred in 1968…that resulted in all time low temp record for Washington State of ? -48F at Winthrop.

    What I foresee happening is that the eastern low/trough will become dominant (still cut off from cold arctic air far to the N)…while ridging amplifies and retrogrades to the west coast…could be one of those fake cold regimes as cold continental (not arctic) fills the intermountain region. This type of scenario was what we saw for much of January 1993 (not the first week when there was colder air around)

    Ridge then would likely retrograde further west into Pacific..possibly to allow arctic air to move into region around New Years or first week of Jan.

    Will see what the models think…maybe the Dr. P. Andersen pattern won’t happen and will have to start from scratch.

  2. W7ENK says:

    Freezing temperatures and icy streets overnight tonight??

    One TV met says yes!

    I say, not so much.

    • alohabb says:

      Which one said that?

    • W7ENK says:

      All I can say is that it was NOT Mark Nelsen.

    • pappoose in scappoose says:

      I think black ice is possible out here. Showers this afternoon/eve, then some clearing…ya.

    • Mark Nelsen says:

      Haha! It was me too. But probably out in Washington and Clark counties away from the urban area.

    • pappoose in scappoose says:

      Probably. Hahaah!

    • W7ENK says:

      I stand corrected. Though I should clarify, said other met TEASED that it might apply to all of the Portland Metro area, only to say later “outlying areas”. I guess I jumped the gun in my BS call, however I still think 34 is too low for PDX tonight.

      Just had another shower here, rain only of course, but the street is wet… again.

      We’ll see what happens.

    • Dave in Sherwood says:

      36.7 here already, I think it could happen tonight.

    • pappoose in scappoose says:

      Think it hinges on clearing, still cloudy here.

    • Punxsutawney aka HIOPHIL in Hillsboro says:


      Will be interesting to see if I’ll be able to ride my bike to work tomorrow. Temp is 40 here right now and dp is 38, so fog is most likely if the clouds overhead clear off.

      But temp and dp’s are dropping, the roads are wet out here, so if it does freeze there could be some good spots of ice especially out toward Banks and Forest Grove, or “Frosty Grave” as my brother used to call it when he attended Pacific University.

  3. 240 on the euro 12z suggest to me inside slider digging trough into PNW, could pull some cold air into PNW, and build ridge to the east. Maybe some snow for Xmas after all?

  4. W7ENK says:

    12/12/12 12:12:12

    The last time ever in our lifetimes.

  5. swift says:

    Models all over the place even in the intermediate range. The ECMWF insist on warm air invading west/central USA while the GEM says no way. The GFS has some warm air coming but it hits the west coast. GEM is too much zonal flow while GFS is best is best for arctic air as -10C temps slide down the border into Idaho. The ECMWF has some potential but as I said before is too aggressive with the warm air coming.

    12z ECMWF:

    12z GEM: http://meteocentre.com/models/gemglb_amer_12/PNM_panel.gif

    12z GFS:

  6. 12z models… No changes…. Colder air mass arrives with cold pool developing over the Columbia Basin leading to lots of east wind and “Fake cold” for PDX. It’s going to be real cold with that wind especially east of I-205 into western Gorge. Still no improvements regarding overall 500mb pattern and ridge placement/configuration to deliver arctic air west of the Cascades, but it looks like modified continental arctic air pushes into eastern Washington and the Columbia Basin.

  7. pappoose in scappoose says:

    Let’s see…what area is lower than the foothills and Coast Range? The land of gravelly plains! Hahaah!

    National Weather Service Portland or
    907 am PST Wednesday Dec 12 2012

    Snow should initially be confined to the Cascade passes and above. However significantly colder air behind the front will drop snow levels into the foothills and Coast Range…and potentially even lower…as Post frontal showers continue Sat night into sun.

    • runrain says:

      I like that potentially lower stuff. And some heavier rain and a bit of wind too. Not just Sat but early again next week. At least some non-boring weather for a change.

    • W7ENK says:

      Unfortunately, that sounds like the perfect setup for a big let down. W to NW post cold frontal flow with plenty of cold enough air in the valley, but the Coast Range gobbles up all the moisture before it gets here, leaving us all looking up at a partly cloudy/partly starry sky wondering WTF happened to all our “lingering snow showers” that never came?

    • pappoose in scappoose says:

      The “potentially even lower” is just a CYA statement, W7.
      Love the CYA lines!

    • W7ENK says:

      True, but the vast majority of the time they do nothing but provide false hope, only to increase the severity of the let down to follow.

    • Light box Erik, light box 🙂

    • pappoose in scappoose says:

      Ya, they really shouldn’t toy with us like that. Hahaah!

    • W7ENK says:

      Haha! Fortunately or unfortunately, all ye fellow weather geeks understand all too well the truth in what I say. Let’s call it “The Coast Range Curse”!

    • runrain says:

      Ah yes. The Pacman Coast Range Gobble Routine. I still think some evil non-weather geek guy is sitting up on Saddle Mtn in the Coast Range blasting those showers with anti precipitation laser rays!

    • pappoose in scappoose says:

      There are times when I don’t want to know the truth. Hahaah!

  8. paulbeugene says:

    The model solutions for the next 1-2 weeks, particularly in week two, are just painful to look at. What I mean by this is that there looks to be a jet suppressed farther south than usual over the lower 48, with this being more or less a split flow pattern, with polar jet displaced far to the N. It just looks too chaotic to make quick sense of the maps.
    That being said…winter precipitation events could sneak up on us…moderately cool to cold continental air (the -4C to -8C 850mb) being overrun by moisture coming up from the SW….without arctic air being involved at all.
    At this point I do not see an snow situation for PDX popping up from the maps. The Euro solution I think is 16km (look in post below) and so it may look like it paints snow for PDX when it is artifact of model “pixelation”

    • gidrons says:

      Not necessarily…
      You’re right on the model resolution and pixelation of course.
      However when a low approaches from the NW or W and tracks south of PDX, it pulls cool, dry air through the gorge. The evaporative cooling will turn the chilly rain to snow on the east side and also potentially around Forest Grove/North Plains area, where the dry air banks up against the coast range. I’m not predicting it will happen, just saying its a possibility with what I see in the Euro.

      None of that does you any good in Eugene, unless you like watching car crashes on the news.

    • pappoose in scappoose says:

      I really like watching car crashes on the news!

    • pappoose in scappoose says:


  9. W7ENK says:

    It’s snowing at my house! Which is weird, because it’s also sunny and looks really warm. I’ll bet it’s doing the same at your house, too! But look quick, because it doesn’t last for long. :mrgreen:



    • W7ENK says:

      That’s because the terrain resolution doesn’t see the Willamette Valley as being 200 feet, it sees it as roughly 2,000 feet, averaged mostly flat between the crest lines of both the Coast Range and the Cascades.

      I thought we all knew this by now…? :facepalm:

      • Mark Nelsen says:

        This is correct, I can take our 36km version of our model and it’ll show snow right over the Valley, but only because the resolution of the output is so low. Go to 12km or 4km and then the snow is in the right place.

    • Pippin says:

      This isn’t the 36km run, its much higher resolution than that. It does spillover the coast range, usually this means 1,000ft or higher for the snow its displaying. Look again there isn’t anything over alot of the valley.

    • Mark Nelsen says:

      Okay, that was the first time I actually spent time on that page. This morning’s run (12z) that’s displayed on there now doesn’t show valley snow. The area that’s all snowy up around Longview is just because the model elevation is higher than reality. Also the “spillover” into the western Valley looks like just a contouring issue to me since it doesn’t show up anywhere else in the valley.

  10. 6z GFS looks just as chilly to me. In fact the colder air arrives a bit sooner arriving in 5 to 5 1/2 days. 850mb temps out around -7c, so nothing too impressive. However, it appears a nice cold pool develops over the Columbia Basin with lots of cold, dry east winds for many days. Looking at 925/850mb and surface temps in the Columbia Basin showed modified arctic air pours into eastern Washington with high temps in the low to mid 20’s and lows in the 10’s. My thoughts are progressively the east wind cools delivering lowered dewpoints and thus high temps in PDX especially east of I-205 fall every day perhaps struggling to reach 32-36F. The east wind may be very strong perhaps a wind event or storm too. I think the chances of this playing out are growing and this is the 5th or 6th model run in a row showing the same thing with things moving up in timing. What I didn’t see yet was a true arctic blast, but don’t rule it out somewhere before/after Christmas.

    • By Xmas we will be buried in snow at least to our ankles record cold with sub zero day time temps below zero at night strong winds blizzard warning from bellingham down to portland area. Now this is only my dream and have no data to back it up.

  11. 6z NAM is really interesting…
    North Pacific view FCST HR 84 – 500mb

    Compare this to last night’s 00z GFS

    Look how much sharper the trough is on the NAM, also the ridge axis is slightly further east and configuration with the strong energy digging across the date line may allow the trough to dig very near the Coast or right down over us with more southward momentum than on previous runs. We’ll see, but I am encouraged by this for a possible colder trough than is currently advertised for next weekend. I wonder if 6z GFS this morning handles things similarly.

  12. you know, i have a friend that lives in anchorage. told me i can come visit whenever. if tickets werent so dang expensive id take up the offer in a heartbeat. id quit my job on good terms, go up there for a year or so? and come back when i was good and frozen.

  13. braniff1 says:

    If you look quick you’ll see that PDX (according to Accuweather) gets a white Christmas with STRONG T-STORMS! How could a weather model even come up with something like that? Let’s hope they’re at least half right. Snow anyone?

  14. 300game says:

    12/11/2012 Oregon (All) Temperature Summary

    High:55 at FLYNN PRAIRIE(1543 ft) & RED MOUND(1753 ft) & MCDERMITT 26N(4464 ft) & Rome(4049 ft)
    Low: 46 at DW1265 Newport(164 ft) & BANDON(79 ft)

    High:25 at Timberline Lodge(7001 ft)
    Low: 16 at KLAMATH NWR (4531 ft ) & Baker Valley (3420 ft )

    Largest Diurnal Change: 34 degrees
    CHRISTMAS VALLEY (53/19 ) (4360 ft )

    Heaviest Rainfall:
    1.04″ at RED MOUND(1753ft)
    0.96″ at PACCTY Pacific C(253ft)
    0.85″ at BROOKINGS(79ft)
    0.82″ at CANNIBAL MOUNTAI(1939ft)

  15. Yes, some serious cold up in AK. But forgive me if I don’t see the pattern as anything but crap. Nice trough @ 240. Maybe some breezy systems. But I don’t see any cold in the PNW in the euro

  16. ***********************************************************
    (and other furry, or um tundra creatures)

    00z ECMWF
    Chilly troughs and SO CLOSE to a major blast. Also, it looks sort of cold over Nunavut moving down into northern Alaska/Yukon/NW Territories. Seriously, has anyone ever see that much Vodka? I have not.

  17. I’ve been mentioning constantly how I believe the 18-20th timeframe is going to deliver, and tonight’s 00z GFS did NOT disappoint. The cold deep trough had been there throughout previous runs in the extended (past 180) and I’d been hoping to see it move up past the resolute change within that same 18-20 timeframe. Hours 156-180 in which a quick hitting trough drops 850mb temps as low as -7c at KTTD with 520 thickness values. While this pattern by itself may not deliver, it should develop the aforementioned cold pool east of the cascades setting up “fake cold” as well. Pretty good pattern.

  18. It’s coming… I think first we’ll see several days of “fake cold” so to speak…. cold east winds, then the onslaught arrives near/after Christmas.

  19. Not really feeling great right now, so I don’t feel like a long post, but 00z GFS is nice…

  20. Jerry says:

    Hot damn 00z gfs la la land is fantastic. Christmas snow storm followed by an arctic outbreak.

    • Now now, you should by now that the GFS model is manipulated by a frustrated guy from Oregon who works for NCEP. They keep him locked up most of the time but every now and then he sneaks into the big room with all those super computers and does this to us. Just jerking our chains. Like nurse Ratched……

  21. Alan says:

    Well, since no weather blog news is usually bad weather blog news, I take it the 0Z GFS was..well..you know?

  22. EY (Oak Grove) says:

    Is Mike (from this blog) safe?

  23. alohabb says:

    Weather takes backseat to unreal tragedy at Clackamas Town Center. Prayers to all involved.

    • W7ENK says:

      My mother was on her way to Clackamas Town Center (less than two miles from my house!) at 3:15 when she turned around to head back home, having forgotten to make a phone call to her insurance about her roof repair. She would have entered at the Food Court and been right in the middle of things when all this happened.

      Someone was looking out for her.

      Thank God for Guardian Angels!!

    • Ron says:

      Frightening time. My wife teaches at La Salle HS and left minutes before it was locked down. She was on her way to Town Center and always goes in through Macy’s Home Furnishings down by the parking lot. She go to the intersection by Toys ‘R US when an unmarked van flew up along side of her. The man jumped out of his van, pulled on his SHERIFF vest, gun bared, yelled to anyone who could hear to not to to the mall and sped threw the intersection. She didn’t go there today! Five or tenminutes more and she could have been in Macy’s.
      There will be many many stories over the next few days for many to tell. It will be a good time to be good listeners to those who have such stories and far more harrowing ones to tell than this one. It is part of a healing process for those who will always think, “what if I. . . . .” to retell their stories albeit 100 times. Weather becomes such a small thing in times like this.

    • ocpaul says:

      My wife and I were shopping at Cost Plus at the Clackamas Promenade as the whole thing unfolded. Unreal.

  24. chris says:

    i need some snow now!

  25. WEATHERDAN says:

    I’M just biding my time until March. Then we will see sunsets after 7PM. And likely our first day over 70 degrees. Until then if we get some cold and snow then good. If not well daylight saving time is just 89 days away.I can see the cliff from here, and no it’s not fiscal.

  26. W7ENK says:

    Looking out the window, today is just… gross.

    Dark, dreary, cold, wet. The sky is the same color as the street is the same color as the river is the same color as the trees are the same color as the buildings are the same color as the air itself. Everything is just a flat shade of gray. It truly is, in a word, gross! 😦

    I really dislike this time of year, this weather is the worst! At least it’s not 35 degrees, that would just be plain obnoxious.

    • Dave in SW PDX (235') says:

      You’re starting to sound like tt-sea, Erik!

    • W7ENK says:

      But somehow, the hilarious dumbassery in this video makes it all better!


    • W7ENK says:

      @Dave, it’s called Seasonal Affected Disorder (SAD), tied to a deficiency of Serotonin due to the lack of sun exposure. Today is the first day I’ve really felt it this season. Even with the sun lamp on over my desk, one glance outside gives me this sinking feeling, almost like dread. I just really don’t appreciate days like today, sorry.

    • EY (Oak Grove) says:

      SAD isn’t a fun problem in the least. I go through that at least once or twice a year, though for me it usually hits at the end of winter and hits even harder if it’s a cold, winter-like spring (read: like the last couple years -_- ).

      Just take the time to enjoy being inside… Stay warm, take a nice shower, sit back and geek out. If it really keeps bringing you down to look outside… Well… At least the sun’s gonna set in like, an hour.

    • gidrons says:

      I make big bonfires and drink…its the only cure I know.

    • W7ENK says:

      Bonfires and drinking, I’m down with that! :mrgreen:

    • germantownsummit1000' says:

      It’s only 38 degrees up here and I’ve been out in it for three hours putting up Christmas (NOT holiday) lights.

      Some of us never learn…

      At least, at the end of the day, I don’t have to go home to the dreaded dome.

      That’s probably worse than normal if you’re affected by Seasonal Affective Disorder.

    • JJ97222 says:

      I am in Memphis working with my new company that will take me to Texas this summer, after living through the last 52 years of Milwaukie weather it is time to celebrate light. I too have been totally brought down by our weather. I have been in Memphis 2 out of the last 3 weeks and the sun keeps on shining I catch myself almost in disbelief of the nice weather here. I try to explain our winters to my new coworkers they just say wow how can you handle that. I truly understand W7ENK the gray does impact how a person feels.

    • Dave in SW PDX (235') says:

      My company used to paint portable “light therapy boxes” that were marketed (by others) as an antidote for SAD. The idea was that, upon waking in the morning, a SAD sufferer would sit in front of the bright light emitted from one of these boxes for approx. 15 minutes as a way to increase their seratonin levels. Sorta like that episode of “Northern Exposure” where one of the characters wore a pair of eyeglasses with a bright light mounted on the inside to ward off his SAD during the long Alaskan winter…

  27. paulbeugene says:

    Going from seasonably dull to seasonably variable but not extreme weather. Ski areas to get snow this weekend. NWS forecast has snow level pegged at 2500-3000′. I think 3000-4500′ more likely.
    Long range. Deep freeze returns to Alaska this weekend. May see -50s to -60s by day 10. Maritime variably cool weather for rain in valleys and snow in mts.
    Ensemble runs: GFS says no arctic air for Xmas, Canadian says slight possibility.

  28. gidrons says:

    The last frame on the Euro 12z is paydirt for pdx. Too bad that its 10 days out.

  29. Call me crazy, but I liked 12z GFS.It looks like a cold pool for the Columbia Basin and lots of chilly to cold east winds. High temps cool off slowly progressively each day and could struggle to reach low to mid 30’s east of I-205….

    • SnowedIn - North Plains says:

      You’re crazy! (jk)

    • rogue says:

      Thanks for posting these updates — they’re always appreciated. Keep them coming, please! 🙂

    • 925/850mb temps reflect cold pool and enough to really cool down PDX with strong east winds. We might be looking at a classic overrunning situation down the road…..

    • SnowedIn - North Plains says:


      Your updates are definitely much appreciated around here, Rob. Thanks for all the time you put into it!

    • Josh says:

      What about up here in Seattle, anything down the road here?

    • W7ENK says:

      I’ve been saying it for months… ice (not snow) is going to be the big weather story for PDX when all is said and done this winter! Things have been lining up that way for a while now, we just need the cold. Looks like that cold will be falling into place here in the near future, or at least the beginnings of cold.

      I’d like to see daytime temps stay below freezing — preferably mid to upper 20s — for a few days, maybe a week, saturate the ground with a good, deep freeze first, then overrun with a wet system from the SW. Not strong enough to bring Southerly winds up the valley, ’cause that will scour out the cold, but sufficiently wet enough for the moisture to actually reach the ground before evaporating completely. Treacherous? Absolutely! So don’t plan on going anywhere for a couple of days. As is always the case, it will all go away soon enough.

      Freezing rain, glaze ice, silver thaw, not quite as good as snow, but it’ll work for me.

    • 12z Euro holds on to some very interesting possibilities with lows off the coast, sliding down from the north on the backside of the high, hmmmmm, maybe the start of a trend?

    • pappoose in scappoose says:

      I really like chilly to cold, strong east winds!
      And I really like it when you like the 12z GFS…you crazy!

    • EY (Oak Grove) says:

      This might be heresy, but I would rather just have bitter cold than have ice. It’s just too dangerous and I’ve known people who have been injured on ice.

      That said, if we had a very short ice day, maybe a south wind scouring event, I might be fine with that.

      Ice is no substitute for snow.

  30. ocpaul says:

    Accuweather is a guilty pleasure for me. It ALWAYS has snow in the extended. But I am really hopeful for this Christmas day forecast. Wow! What a combo:

    • Seattle better times 200 Strong thunderstorms with snow. Now i wish it come true and really happen. http://www.accuweather.com/en/us/seattle-wa/98104/december-weather/351409

    • Mark says:

      A. I believe AccuWeather simply takes a model (the coldest run of the bunch) and makes that their long-range – at least during the winter months. If their long range ever panned out to be 50% accurate, Portland would be buried in 50″ of snow each year. I believe it’s what could be called “weather trolling” for web hits.

      B. Many runs for the long-range (EMCWF, GFS, etc.. as Mark points out) are certainly not coming into agreement for the long-range. I’m an optimist, so I consider that a good sign/opportunity for cold weather…

    • W7ENK says:

      There’s a reason why we lovingly refer to them as InAccuweather. You’re seeing that reason first hand, right here, in these ludicrous forecasts. I have a better chance of pulling a more accurate weather forecast at random out of my … … … hat. o_O

  31. Jake says:

    When is our next 80 degree day?

  32. 12z GFS 2 hours
    12z ECMWF 4 hours 19 minutes

  33. Good Morning,

    00z GFS Ensembles
    6-10 Day 500mb Height Anomalies

    11-15 Day 500mb Height Anomalies

    00z ECMWF Ensembles
    6-10 Day 500mb Height Anomalies

  34. swift says:

    The new 00z GEM that just came out is the first to bite at a possible arctic outbreak. -10C temps at the Canadian border, just need it to move down a little further and we are in business. This is at hr 228.

  35. http://meteocentre.com/models/gemglb_amer_00/TT_GZ_UU_VV_228_0850.gif says:

    00z GEM that just came out looks to be the first to bite at a possible outbreak. -10C temps at the Canadian border at hr 228.

  36. EY (Oak Grove) says:



    Mark’s saying 32 for the low Thursday and Friday…

    I’ll TAKE IT!

  37. eugene in vancouver says:

    We get snow in the mountains every year. I want snow on P street!

  38. bgb41 says:

    12/10/2012 Oregon (All) Temperature Summary

    High:66 at RED MOUND(1753 ft)
    Low: 51 at RED MOUND(1753 ft)

    High:25 at HOWARD Mt Howard(8150 ft)
    Low: 15 at CHLOQN (4231 ft )

    Largest Diurnal Change: 30 degrees
    KLAMATH NWR (49/19 ) (4531 ft )
    Sand Creek (US 9 (48/18) (4525 ft)

    Heaviest Rainfall:
    1.12″ at WANDERER’S PEAK(4350ft)

  39. W7ENK says:

    Are you sure? Is it true?? Could it be???

%d bloggers like this: