Quick Evening Update

9:30pm Wednesday…

Not much change in 00z models tonight with most of them just skirting the Portland metro area with snow later Thursday night and Friday morning.  If there was any movement, the precipitation is slightly closer to us.  Here’s the WRF-GFS model showing accumulations of snow as close as the western suburbs and down around Woodburn and then south.

00zWRF_snowtotal

 

Still looks great for at least 1″, maybe more, in the areas mentioned in the previous blog posting.

Our 00z RPM is even more white than its earlier run, producing a swath of decent snow all down I-5 from Olympia to Medford!  I’m ignoring it…for now.

Models are now pushing even colder air than expected down out of Canada later Friday through Sunday.  I see the NAM and GFS both have 850mb temps down to the -12 to -15 range.  That would be about 10 degrees fahrenheit at 4,000!  We haven’t been below the -12 to -13 range since before 2007…I don’t know when.  The lowest in December 2009 was -12.3 at Salem, and -12.5 in November 2010.  February 2011 and December 2008 only bottomed out around -10.  The 2008 number surprised me.  Of course what models predict and what actually shows up on the sounding can be different.

Regardless, we have a true “arctic air” weekend coming up here in the Pacific Northwest.  High temps only in the upper 20s to 30 in the metro area.  Low temps in areas with bare ground and calm wind should be in the 10-15 degree range.  If we get snow cover down the valley, it’s going to be the coldest we’ve seen down there in many years…into the single digits!

Chief Meteorologist Mark Nelsen

 

 

88 Responses to Quick Evening Update

  1. Jason Hougak says:

    I believe this happened in Feb. 1993 or 94′. We had 18-20 in Boring. Low stalled and spun up a tremendous amount of moisture. I was 13-14 and we rode quads over a week. That was a snowstorm i’ll never forget. The cold air in place and colder air coming things could be getting interesting. I’m praying for snow!!!

  2. J-Kelso says:

    Some flurries here in Kelso.

    • David B. says:

      Clouds are really thickening up here. Maybe we’ll see a few? Forecast discussion does mention the possibility.

  3. JohnD says:

    Things are especially compelling because the models
    are “so close”. Even a minor wiggle would make ALL
    the difference. I won’t be throwing in the towel
    until tomorrow, if at all! ‘Gotta believe!

  4. David B. says:

    Harrumph!

    THE CANADIAN SOLUTION BRINGS UP THE POSSIBILITY OF LIGHT SNOW MONDAY NIGHT WHILE THE SLOWER ECMWF AND GFS TRANSITION TO A WARMER AIR MASS QUICKLY ON TUESDAY. WARM ENOUGH SO BY THE TIME THE PRECIPITATION STARTS IT WOULD BE IN THE FORM OF RAIN. THE EXCEPTION BEING THE POSSIBILITY OF COLD AIR BEING TRAPPED NEAR THE HOOD CANAL WITH THE SOUTHEASTERLY SURFACE GRADIENTS. WITH THE CANADIAN STILL HOLDING ON TO THE FASTER SOLUTION WILL NOT MAKE ANY CHANGES TO THE EXTENDED FORECAST THIS MORNING KEEPING THE CHANCE OF SNOW IN THE FORECAST MONDAY NIGHT. CONFIDENCE IN THIS SCENARIO IS WANING AND IF THE 12Z MODELS COME IN WITH A SIMILAR SOLUTION TO THE 00Z GFS AND ECMWF LOOK FOR THE SNOW TO BE TAKEN OUT OF THE MONDAY NIGHT FORECAST.

    One step closer to the cliff….

  5. paulbeugene says:

    FYI the 12z euro has at least trace amounts of snow for ENTIRE state of Oregon.
    3.2″ EUG
    1.7″ CVO
    0.9″ SLE
    0.2″ PDX
    2.5″ Florence
    1.5″ RBG
    4.1″ MFR

  6. Jane - Forest Grove says:

    Do I smell ‘Forest Grove Effect’ tonight?

    • Aloha Rainshadow says:

      Jane, this is a bit different than the “Forest Grove Effect,” In marginal situations with cold air flowing in from the gorge, it can get banked up against the coast range, thus when Hillsboro, Aloha, Beaverton and PDX are getting rain, the snow falls in FG because the pool of cold air is deeper there. Cold air will NOT be the issue tonight, it’s the supply of moisture that is the issue. The further west and south you go, the better chance of snow. One thing that could be good for you is once the low gets south of your location, since moisture would rotate NNW and eventually NW…possibly, the coast range could squeeze some extra moisture out for you…but it shouldn’t be a big difference. For this setup, farther south you go, the better, simple as that.

  7. Model Rider says:

    I know were still in the “event” which is mainly just bitter air, but after yesterdays and todays models, it looks like once our block in the pacific that is causing us to be cold breaks down, a new one pops up about 6-7 days later. What are thinking about that Rob?

    • David B. says:

      I’d like to see some snow between Christmas and New Year’s. Not a whole lot, just some. Going to be spending some time in a cabin in the woods on the Olympic Peninsula and a little snow would be nice, maybe 4 to 6 inches max. Any more than that might complicate getting there or back.

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