First Snow & Rain Moving Through At Midday

11am Wednesday…

So far things are going about as planned weatherwise.  Temps dropped to below freezing for most of us last night.  As of 11am all parts of the Willamette Valley up into Kelso/Longview are above freezing, a gusty east (cold) wind is blowing out of the Gorge, and a bit of “downsloping” southeasterly wind has arrived in the Cascade foothills, central Willamette Valley, and Clark county.

Now the first band of snow and rain is passing overhead.  I’ve seen reports of snow in St. Johns, McMinnville, but just rain in central Portland.  A mix in Beaverton too.  Looks like McMinnville was able to get a dusting as that passed overhead:

mcminnville

WHAT’S HAPPENING AS OF MIDDAY?

At 4am the balloon sounding over Salem said “all snow”; the air was below freezing all the way up through the atmosphere.  But that has changed; there is a huge storm that has developed off the coastline.

satellite

We are on the east side of that storm, which means strong south and southeast wind developing in the lowest few thousand feet of the atmosphere.  The air just above the surface up to around 3,000′ is warming quickly.  That continues until a cold front passes overhead around sunset (the sharp back edge to the cloud cover).  So for the next couple of hours it’ll be a rain/snow mix until temps get a bit warmer overhead.  As you can see the temperatures down here at ground level are too warm to allow snow to stick and we’ll remain above freezing through tonight.

web_metrotemps (1)

All the mesoscale models (with better terrain and resolution) say no sticking snow in metro area tonight, including Clark county.   The WRF-GFS model was perfect showing temperatures rising up to around 40 or higher in a weird sort of southeasterly “downslope” wind flow up there.  Here’s the snow forecast through 4am

wrf_snow4am

and the NAM-NEST model is similar, this is ending at 1am

namnest_1amsnow

The mixed precipitation should change to all rain as the main cold front band passes overhead 3-7pm.  After that it’s frequent showers tonight.

SUMMARY FOR LOWLANDS WEST OF THE CASCADES

  • Mixed rain/snow continues at times through early afternoon, changing to mainly rain.  Although a mix likely continues up in northern Clark County and maybe Columbia County around Scappoose and St. Helens.
  • Mainly rain showers tonight, although mixing with snow on hills.
  • Could see a trace to 1″ eastern metro hills up around 1,000′ and above.  1-3″ above 1,000′ possible any of the Cascade foothills (east of Battle Ground, Camas, Sandy, Silverton etc…)
  • Freezing is unlikely in metro area tonight.  But just like the last few nights, there could be spots where breaks in clouds allow some local freezing.  If it happens most likely it’ll be west metro areas.
  • Scattered light showers Thursday, still mixing with snow at/above 1,000′

 

COLUMBIA RIVER GORGE

A bit more complicated here because a shallow layer of cold air isn’t going anywhere.  This isn’t quite the typical situation since the real cold air is only about 2,000′ thick.  But since it’s not a real warm atmosphere overhead there should be no problem keeping precipitation type as snow from Bonneville Dam eastward.  There’s a very narrow area at the west end of Gorge that will see freezing rain late this afternoon/evening.  That’s from near Corbett/Cape Horn east to about Multnomah Falls.  Then back to a snow/rain mix later tonight in those areas.  So east of Multnomah Falls or Bonneville, expect a Trace to 4″ in the Gorge.  The trace would be out near The Dalles…just not that much precip to work with.

 

 

47 Responses to First Snow & Rain Moving Through At Midday

  1. JERAT416 says:

    I remember seeing someone say recently “Portland has seen measurable snowfall the last 3 winters”. Well, the problem is like last winter, it can miss south and west suburbs altogether. I generally only count region wide events. In which case the last one was January 2017. I wish we could create an official definition of a “pdx snowstorm”. Maybe take a dozen random cities that represent the suburbs from all directions, along with Portland. Then say if (for example) 2/3 of the cities have measurable snowfall, we all agree it counts. But if it misses a huge area, such as west of I-5, south of the Columbia, west of the willamette, etc then we all agree it didnt count.

    • lurkingsince’14 says:

      I second this, last year we had no appreciable snow in West Portland. That 7” ‘official’ total is a farce!

    • Tanis Leach says:

      I second 2019. 2018 I count as a snowy winter as everyone in the metro for the Feb snowstorms got in on the action and got 4 inches (average). When I originally made that point to the OSU AMS chapter (yes they have one), I was met with criticism.

      • W7ENK says:

        Nope, not everyone. Out of 7 separate shots at accumulating snowfall last winter, Milwaukie saw a measly 1/4 inch of slush, total. They all missed us, stopped short by mere miles. So believe me, saying “everyone in the metro … got in on the action” is a wholly inaccurate statement.

  2. JohnD says:

    39.7’ currently here @ 200’ in inner SWPDX. 37.0’ when I came home @ 4:30 p.m. Remarkable what a southerly will do to a perfectly good East Wind flow!
    Thinking back to 2008-09. We were still living in E County (Troutdale). A residual winter weather conducive pattern lingered into Jan. that season—even after the huge events of Dec.
    (Photos of our buried car and 3 foot drifts in the backyard alive and well in the family photo album—like a lot of us.)
    I recall one Jan. Sun. evening that year with the East Wind in play—3” of fluffy snow fell quickly. And just as quickly the southerlies kicked in and it was gone seemingly in an instant!
    Like all of us, I sure wish for another period of winter weather this year. Even though nothing much materialized here locally this round, it was at least intriguing having the potential. It would be great if another pattern ensues. Still time!

  3. WhateverTheWeather says:

    Made the move this fall from Orchards area of Vancouver to Washougal and it’s paying off. 420′ near the Washougal River and I have 2.5 inches that has fallen this evening. Still coming down good. 29.7 degrees here.

  4. boydo3 says:

    Crazy weather day down here today. High winds, heavy rains and a t-storm thrown into the mix.
    https://www.wrh.noaa.gov/mesowest/timeseries.php?sid=K92S&num=72&banner=gmap&raw=0&w=325

  5. W7ENK says:

    Quite the active little lightning storm just a few miles offshore from Newport, tracking straight toward Portland Metro.

  6. ocpaul says:

    First 2020 snow in Portland metro, December 8.

  7. W7ENK says:

    Southerly wind suddenly gusting above 30mph in Milwaukie. Several gusts “WHOOOOO”-ing through the chimney, and the Dougies in the neighborhood are roaring.

  8. Andrew says:

    The irony is that I wouldn’t be surprised at all if Friday morning generates the most “conversational” snow we’ve seen all week, long after us weather geeks have already moved on now that chance for a legit east wind event has come and gone. Nothing will stick below 500-1000 feet but all models, even the more conservative Euro, seem to give us a cool enough upper atmosphere to produce flakes in air. I could be wrong and i know Mark and team aren’t dropping icons on the 7 day, but it definitely wouldn’t surprise me. Still an absolute dud of a week weather wise. I’m moving on to long term trends hoping for another miracle dip of that cold Canadian air. So far, nothing positive to report.

  9. rmlounsbury says:

    Well, the last little bit of snow has left my area. I was up on Prune Hill in Camas (as high as one can get w/o going into the Cascade Foothills in SW Washington) and it was mostly rain with a snowflake or two.

  10. Evan -- Cedar Mill says:

    Feels like spring outside!!!!!!!!!!

  11. rmlounsbury says:

    The Mesonet reporting for the Glen Jackson Bridge is amazing. Right now it shows -38 for current temp and -81 degrees for DP.

  12. runrain says:

    Friend in Friday Harbor San Juans reporting a foot of snow.

  13. Tanis Leach says:

    https://forecast.weather.gov/wwamap/wwatxtget.php?cwa=pqr&wwa=severe%20thunderstorm%20warning

    Severe thunderstorm warning for Coos county. I did not see that coming.

  14. rmlounsbury says:

    Well, out towards Lacamas Lake we are still hanging onto snow for now. The east winds are howling.

  15. Grizzly Bear says:

    I sure noticed that the blog got a lot of bickering and “told you so” after the big snow storm fizzled….Makes for an interesting read…just observing.

    • MasterNate says:

      Happens every time when tantalizing models don’t perform as desired and mother nature doesn’t deliver the goods.

    • rmlounsbury says:

      We are fickle creatures. 🙂

    • Tanis Leach says:

      It would’ve happened the other way around if the snowstorm happened. That’s just humans.

      • Larry says:

        We were destined for another snowless winter here in Portland. We usually get those once every 5 years (Think 07-08 and 12-13), with the rare occasion of 14-15 where we saw another 0 winter following a big snow year.

        Now, if we didn’t see anything the rest of winter, it’s safe to say we can throw in analog years like 92-93, 97-98, and 13-14 as solutions to what may happen NEXT winter.

        As for arctic blasts, I would throw in it as a wildcard. It is certainly possible we see an arctic blast and a big snowfall all in the same year (2013 flashbacks). I’m getting a little ahead of myself now, best to wait until October to start talking future winter. I bet the conversations will be great!

  16. Registered Nerd says:

    Conversational snow in SW Pdx!!! All my snow fantasies are realized!!!!!!! :(…..

  17. Roland Derksen says:

    Well, what a morning we’ve had here: Everything white under a 6 inch dump of snow overnight. It’s not a record- but it’s at least the most snow I’ve seen come down here from a system in the month of January since 2007. And- there’s more to come tonight!

    • Got 5″ of squeaky-cold powder overnight in Bellingham. It was supposed to be above freezing by now here, but the Fraser outflow is holding its own so far. The Chuckanut Mountains just to the south of me got quite a bit more, and you don’t have to go up in elevation very much to see the change.

  18. runrain says:

    Crown Point gusted to 70 mph within the past hour.

  19. Andrew says:

    How is WRF-GFS different than GFS and where does one find it?

  20. Hansen Paul says:

    Snowing up on Livingston Mountain, north of Camas at about 1000’

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