Mark 1/31 Wx Graphic

January 31, 2019

1pm Thursday…

We’ve had all of ONE significant weather event this whole cool season.  That’s 3 months of boring weather since Halloween!  Now as we approach the end of “West of the Cascades Winter” it looks like we finally have something to talk about!  Yes, in our climate west of the Cascades almost all interesting weather happens (in most years) before Valentine’s Day.  This has also been one of our warmest “cool seasons” on record in the Portland metro too.  But beginning Monday we’ll be feeling some much overdue cool temps and crisp days.

I’ll just skip past the snow hype; here are the details…

THE FIRST HALF OF FEBRUARY LOOKS CHILLY!

  1. At this point I don’t see a setup for a snow/ice storm west of the Cascades; not one of those events where cold air pours out of the Gorge and we get a solid/frozen day in the lowlands and the metro area grinds to a halt.  Please don’t abandon your car on the freeway tonight in anticipation
  2. No sign of freezing rain
  3. No sign of a big freeze at this point either
  4. What I DO see is a few “flirtations” with low elevation snow next week, first chance is late Sunday night/Monday AM and again maybe Monday night/Tuesday AM.  Possibly late next week.
  5. If you live near/above 1,000′ you’re almost guaranteed at least some snow at some point Sunday night through Tuesday AM.
  6. NOTHING INTERESTING HAPPENS THROUGH THE WEEKEND, INCLUDING THROUGH SUNDAY EVENING.  YOUR PARTY PLANS AND DRIVE-HOME-AFTER-PARTY PLANS ARE GOOD TO GO.

For now this is all about one of those sloppy wet snow shower events where some of us get it and some don’t.  Some get a dusting overnight and during the daytime most roads are just fine in the lowlands.

LET’S CALL THIS THE ITTY-BITTY POLAR VORTEX 

That’s because there is a small little upper level trough that swings through the Pacific Northwest early next week.  It is a “break-off” of the polar vortex always in place in wintertime across the arctic.  See it on the slide show…use the arrows if you are in a hurry.  See the little cold pool swing down over us?  The timing is Saturday through Monday night with these graphics

That pool of air swings out over the ocean.  Then the cold Canadian air picks up moisture at the surface, and moves inland as cold showers.  Of course that very cold air is moving over 50 degree ocean water first which warms up the airmass.  That’s why this weather pattern typically does not bring us snowstorms in the lower elevations west of the Cascades; or even in the Gorge.

Of course this is still 3+ days away so I don’t have any more details for you with respect to how much might fall (if any!) in YOUR neighborhood.  If you’ve seen any snow forecast maps on the internet, don’t get too excited.  Each model is slightly different and I looked at ALL of them this morning.  A few things I notice so far…

  1. Over the past two days models have pushed that cold trough farther west, going out over the ocean as I just mentioned.  This may be due to our general winter pattern (which continues through early February) of weak and “splitty” systems.  Any farther west and we could end up mainly/all dry Sunday through Tuesday.
  2. Models have turned warmer the past 48 hours as well.  The GFS bottoms us out at a “marginal for snow” -7 degrees at 850mb.  ECMWF is now only a -7 to -8 Monday-Wednesday.  They were down around -10 to -12 at one point (mainly ECMWF).  If they back off much further we can say goodbye to snow chances for many of us in the lowlands.
  3. The GFS and GEM, due to the orientation of the upper-level pattern, allow dry and colder modified arctic air to drift into Eastern Washington, come through the Gorge, and into the metro area.  If that occurs, we’ll be REAL cold Tuesday and beyond.  For now I’m discounting that in our 7 Day forecast.
  4. Cold arctic air will be sitting close by (just north/east) for most/all of next week.  Any surface low that develops west of us or comes down the coastline?  We would be in the snowstorm business like late February 2018 or early February 2014.  At this moment I don’t see that on any models.

This next 10-14 days should be real interesting for weather geeks like me; apparently an “end of season” payoff, or at least an attempt at some weather fun.  Take a look at those chilly EURO Portland temps

kpdx_2019013112_eps_min_max_15

The chance for getting SOME snow at SOME point in the next two weeks is the best we’ve seen the entire season.  15 of 21 GFS ensemble members are producing at least 2″ snow (total) in the next 15 days.  At Salem, 40 of 51 ECMWF ensemble members produce at least 2″ snow (total) in the next 15 days.  Odds are definitely looking up

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