Big Snow Weekend in Cascades

SnapshotIt’s looking as if this last cold storm of the 2 week string will be the biggest for the Cascades.  Not such a big deal in the lowlands with less than 1" of rain though.  The 00z NAM shows 850mb westerly wind (around 4,500′) at or above 45 mph from 4pm Saturday to 4pm Sunday.  At times it averages over 55 mph!  This is very strong for the mountains and will probably squeeze out incredible amounts of moisture.  Our RPM model seems to agree.  It says 25-30" of snow accumulation in the Cascades by 7pm Sunday!  This is the most I’ve seen it forecast for any of these storms.  Sunday and Monday are going to be big powder days!  And you get sun with the powder on Monday as high pressure settles in.  I know thicknesses and 850mb temps support snow to 1,000′ or slightly below Sunday, but it’s a heck of an onshore southwest flow all the way through the evening.  Way too much mixing to get low level snow if you ask me…but at/above 1,000′ it’s more likely, especially in the orographic areas against the Coast and Cascade range foothills.  That’s why I downplayed the chance of snow in the metro area Sunday.  Moisture probably disappears soon after sunset Sunday too.

Speaking of high pressure, it quickly builds over the Intermountain Region later Monday and is quite strong by New Year’s Morning.  Looks like 10-12 millibars are likely through the Gorge on Tuesday and Wednesday with a very chilly airmass trapped in east of the mountains.  This will be the first time we see gusts over 70 mph in the Gorge this winter.  This is probably not the pattern that gives us downslope wind off the Cascades.  So not much east wind west of I-5…strictly a Gorge/East Metro event.

Now you’ll notice I put a 38 for a high Wednesday.   Assuming a system moves in from the west as forecast, the airmass east of the Cascades should be cold enough to produce freezing rain or snow in the Gorge.  It’s a bit too early for details, but some freezing rain is likely at the west end of the Gorge and POSSIBLY the portion of the metro area near the Gorge…definitely not a snow setup with warm air above.

The brief break in the weather sure isn’t going to last long!  Long range models throw us right back under the "storm train" beginning Thursday.  As always each model is different, but they all have powerful areas of low pressure moving quite close or over the West Coast.  Lots more fun on the way in this La Nina winter!  Next post on Monday…Mark Nelsen

535 Responses to Big Snow Weekend in Cascades

  1. Rob aka Gradient Keeper -Far S.E. Portland- says:

    A real shame… Portland’s 13 game win streak snapped largely in part due to the refs… I’m not sure how many of you watched the game, but the officiating was ridiculous, especially during the 3rd quarter and the first half of the 4th quarter. It is very difficult to win on the road, but it’s even worse when you are playing 8 on 5. It was literally as if David Stern said tonight, “I think Portland’s streak is too long.” Honestly if you watched the entire game you would agree.
    Back to weather…
    TTD-DLS -5.4
    Partly-Mostly cloudy.
    Temp: 39.2F
    Dew point: 25F
    Highest Gust: 32.2mph

  2. S.D. (North Portland) says:

    East winds have finally made an appearance at PDX; temp has bumped up from 32 to 36 there.
    Happy New Year everyone!

  3. Anonymous says:

    Hey Josh….where did that info come from??

  4. seamles_transition says:

    Hey I had a question for all you weather geeks out there. All or any of these questions being answered would be so appreciated.
    I got one of those altimiter/barometer/compass/weather forecasting watches for christmas, and as I wear it, I have more questions than I do answers it seems.
    1. Are there any areas in the Portland Metro area below sea level? It shows where I work on airport way and holman to be -10 to -15 feet.
    2. How can I tell what the altitude REALLY is when the barometer falling increases the altitude reading, and rising barometer lowers the altitude reading?
    3. What is the most accurate place or way to set my barometer so it stays accurate (I use the “right now” weather forecast for now, it seems to be right on or very close).
    4. Does barometer change place to place like just a few miles or less?
    Sorry for how long this is, but you all of you know more about weather than me. I am researching as we speak about this. Thanks for your time.

  5. Happy New Year, ya’ll…if your heading up the mountain, everything off of 26 in the shade is a skating rink already tonight…

  6. josh says:

    Oh, that would be the cascade forecast :).

  7. josh"fromEverett,WA" THE SNOWMAN says:

    Snow levels will be hitting the deck by the end of next weekend. No worries all :).
    LEVEL 1500 FEET.
    500 FEET.

  8. Anonymous says:

    when do the e winds arrive for you folks out east? Hope the lights stay on out there :0)
    Happy New Year everyone!!!

  9. josh"fromEverett,WA" THE SNOWMAN says:

    Happy New Years all. About time to get the drinking going!!
    Don’t worry I’m not going anywhere tonight, just going to hang out and get blitzed with the wife…ha ha ha.
    Here’s a good song to get us going:

  10. Anonymous says:

    di you get my email address Heat?

  11. IceKeeg - Beaverton 'bout 200 foot elevation says:

    Breezier than I thought it would be on the westside. Keeping temps from doing a free-fall at the moment – 37.2, ’bout the same as earlier this afternoon.

  12. Now foggy
    31.5°, DP 29.9°
    Very light winds from WNW

  13. Anonymous says:

    same here T.A, & very foggy now. Glad I am not driving tonite. Jes sparkling cider fer me LOL

  14. Heatblizzard silverton Or near the gardens elevation 360 ft says:

    Hey did you know this lanina is still singing? I’ve heard on western forums that it is forcasted to peak in late winter which is an odd time. I think our “goods” will come in spring with sudden temp drops like a few days ago but more often.

  15. T.A. (Foothills NE of Woodland) says:

    All white here still…can’t see the grass in the yard. Not much of a melt-off today.

  16. josh"fromEverett,WA" THE SNOWMAN says:

    A good widespread snowstorm/deep freeze would be nice. I know we will get one this year, why not next week??
    BTW, looks like Roper is the leading candidate to replace Dixon next year. As was the case with Dixon, he needs to beef up some….Or that dude is going to get hurt!! Kempt ain’t bad either though.

  17. Heatblizzard silverton Or near the gardens elevation 360 ft says:

    We have a friend there. It’s a nice mountain town look it up on microsfot maps or somethin. I don’t think we are goin to get cold anytime soon. The jet is going to cause East of the mississip to be Butt cold like Chicago with a high of 20 and Snow north of NYC like 6-10 inches for Buffalo NY and Mild and a ridge for the entire West. I wonder what that will bring us?

  18. gratefulduck (weather blog lurker) says:

    uh.. Josh… a big snow storm in portland…that is the only other thing that can make winter now….
    Ducks looked like the Ducks of old!!!!!!!

  19. J.R. on cell (sidekick LX) at work says:

    I know what we could ask for.
    The blazers getting 14 without coach nate tonight

  20. S.D. (North Portland) says:

    Wow…saw the Sun for a whopping 3 minutes before more thick fog came back with a vengeance. Temp has been 34-36F all day here.

  21. josh"fromEverett,WA" THE SNOWMAN says:

    Ducks kickin butt. Models and trends looking good towards the end of the week. What more could we ask for??
    This is the first time this year that I’ve genuinely gotten excited for a cold snap. But based on everything I’m seeing next week should be the real deal. I would expect some sort of Special Message from the NWS by Fri/Sat.

  22. Ryan (Swan Island) says:

    Willow Creek Apartments out in Hazel Dell (Vancouver). I didn’t even know there was a Willow Creek, CA. 🙂

  23. Heatblizzard silverton Or near the gardens elevation 360 ft says:

    It was jacobs not justin

  24. Heatblizzard silverton Or near the gardens elevation 360 ft says:

    Okay I am ready to respond to Justins mail and Cheries can someone post the link. I am up for now.

  25. Heatblizzard silverton Or near the gardens elevation 360 ft says:

    Ryan Do you mean Willow Creek CA? That is in the mountains. I am pretty sure they get snow.

  26. Professor Gregg formerly known as Gregg-Troutdale says:

    Getting chilly now with the E winds picking up. Currently 37.8, E winds 15-20, and a gust to 30.9. Great bowl win by the Ducks today, and very impressive. Stewart was phenominal, shattering the Sun Bowl record with 253 yards. Lot of records broken by the Ducks today.

  27. SnowFlake (Tigard/Bull Mtn) says:

    DITTO Rob.
    Happy New Year everyone!!

  28. J.R. on cell (sidekick LX) at work says:

    A week is so long time from now weather wise. It can change so much

  29. Rob aka Gradient Keeper -Far S.E. Portland- says:

    Corbett gusting over 40mph with only a -3.5 to -4.0 TTD-DLS gradient now… Not bad…
    Well need to rest the neck.. Happy New Year everyone! Have a very safe and great night if you are going to be out celebrating.
    (Absolutely NO drinking and driving in case anyone is going to be consuming their favorite alcoholic beverages.)
    I hope the New Year brings you want you wanted or need and happiness and good memories to last a life time.
    Be back later.

  30. SnowFlake (Tigard/Bull Mtn) says:

    And for some reason, this pic just makes me smile…

  31. SnowFlake (Tigard/Bull Mtn) says:

    Well, if I can’t have snow at my house, at least looking at this picture tides me over…. 😉

  32. Rob aka Gradient Keeper -Far S.E. Portland- says:

    Yeah just in the knick of time…. Let me tell you if you do not have an existing pole or chimney, etc to put the wind sensor on your roof it is a PAIN in the butt to setup…. Yeah I’m just hoping I crack 40-45mph or so.. Wishful thinking for 50mph, but never know.

  33. Cherie_in_Vernonia says:

    I know….I can hardly wait to hear! I’ll bet you are anxiously awaiting. Great timing for you to have E wind coming so soon after you got it working :0)

  34. Rob aka Gradient Keeper -Far S.E. Portland- says:

    Thanks…. Yeah I’m happy with it…. Thinking I’ll be 45-50mph or so later as the E wind cranks up.. Well that’s the plan Lol

  35. Rob aka Gradient Keeper -Far S.E. Portland- says:

    As of 3:00 PM
    TTD-DLS -3.5

  36. Cherie_in_Vernonia says:

    congrats Rob on the weather station! I am sure it will be a joy to you this winter!!

  37. Made it up to 43.9° today, cooling quickly now.
    I see fog starting to roll in from northwest.
    Temp 36.5°, DP 32.4°
    Very light NNW wind

  38. J.R. on cell (sidekick LX) at work says:

    Nice rob that is awesome. I got to get me one of those weather stations here soon

  39. Cherie_in_Vernonia says:

    no moisture around til Tues PM right??

  40. Rob aka Gradient Keeper -Far S.E. Portland- says:

    As of 2:00 PM
    TTD-DLS -3.2
    Latest 18z GFS from NCEP looks like the E wind may get a bit stronger than previously thought. As always things are subject to change.
    Oh btw I finally have my wind sensor/station up, so now I can report winds speeds/gusts OFFICIALLY. Sure is nice to be able to say that!

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