Lots of Exciting Weather Ahead

The coldest night of the winter for many of us westside is in progress right now.  Yes, some places were colder earlier in the winter, but it’ll be close.  Still waiting for the north wind in the Valley and east wind in the Gorge to completely decouple from the surface.  With dewpoints around 10 many areas, it should be easy to get down into the teens.

So we’ve got moisture moving in tomorrow night, cold air in place, and a perfect setup for a brief snowfall?  That forecast above is the 72 hour period ending Monday afternoon.  Note it shows possibly a dusting (spotty) in the Valley.  Possibly, but I see two things working against it (and mesoscale models seem to agree) getting more than a dusting:

1. Moisture is very slow to move in and quite light from late Saturday evening through daybreak Sunday…just a few hundreths of an inch.  Not the best if you want really good evaporational cooling.  That moisture dropping into the cold air and evaporating, thus taking “heat” out of the airmass.  Temps cool as that occurs.

2. Onshore flow commences by sunset tomorrow, picking up, and by Sunday morning we’ll have a breezy southwest wind blowing up the Valley and THROUGH the Gorge too.  Not a real warm airmass, but should be enough to lift the snow level up to 1,000′ or so.

Once we get past that, the threat for widespread snow in the LOWEST elevations is over, but it’ll be close off/on through the next 7 Days.  If you think of a late-winter La Nina weather pattern, this would be it.  Many feet of snow in the Cascades and even down into the foothills through the first week of March.  Models show 2-3ft. of snow just from Sunday midday through Monday afternoon!  It’s unusually cool westerly flow through the whole 7-10 day period.  Looks like Monday night the snow level is back down around 1,000′ again (briefly).

Chief Meteorologist Mark Nelsen

658 Responses to Lots of Exciting Weather Ahead

  1. muxpux says:

    new post

    • Kathey Reed says:

      It has been snowing in Vernonia,Or. all day,slacked off and turned into rain for about 10 mins. then went back to snow.

  2. stevied (North Portland) says:

    WRF-GFS showing some 50-60mph gusts in the Willamette Valley on Wednesday. Something to DEFINITELY keep an eye on!

    • Rob "Wrath" S.E. Portland says:

      PDX-EUG of 12-14mb. Low deepening even as it passes north of PDX inland into Washington. Tight, compact low, no double barrel structure. I would estimate gusts 55-70mph. If there is good mixing possibly stronger. We need to closely watch future runs(Primarily the 12Z/00Z WRF) to see how it handles this low especially if it deepens it further. It could do so, but just the same the low could be weakened or track differently in the days to come.

  3. TAGinGresham says:

    So the radar is showing blue, but who thinks we will actually see snow tonight, and if so how much?

  4. Kyle says:

    Thanks for the replies on the situation folks!

    I love how you are all so knowledgeable while I am just trying to figure out what all the lines on a wind chart mean.

  5. Brandon (Damascus 650ft) says:

    PDX reporting light snow at 10pm?

  6. Wendy-Silverlake,WA says:

    WooHoo, it’s finally warming up. I’m at 27.9. That’s the warmest it’s been today. I want my driveway to thaw out so I can go somewhere!!!!!

  7. W7ENK says:

    My high temperature today is 34 degrees, which is the temperature right now. I hope it goes back down soon.

    • pappoose in scappoose says:

      The chances of that happening are between 0 and none W7. Obviously with moisture approaching, the dome will maintain your temp at 33 or above. Should the dome fail at this, we know frozen precip will not penetrate anyway. Hahaah!

    • W7ENK says:

      I hope not… I really don’t want to spend the next three days complaining again. 😆

    • Boydo3 500' North Albany says:

      Had a high of 38 today. 32 now with a light S wind. Erik, I think you might have a super volcano under you. Call Kyle NOW!

    • Kyle says:

      Who is Erik?

    • W7ENK says:

      Up to 35.6 here now. Every 0.1 degree increase is a new High at this point. How high will it go over the next 97 minutes, I wonder?

      @Boydo: I just thought it was all the heat radiating from my deep-seeded hatred for this pathetic life I claim as my own…

      Okay, maybe that was a little emo? My bad. Had a rough afternoon, and now I’m drowning it in alcohol. Maybe I should just close my blog tab… o_O

  8. nsbfdarlene@aol.com says:

    I just went outside…I can’t figure out what it is doing out there. In the light, it looks like rain but sounds like freezing raining when it hits…but isn’t coating like freezing rain. Tiny granular’s on surfaces but it definitely looks like rain as it falls. Temp is 30F…any idea’s?

    • Rob "Wrath" S.E. Portland says:

      Kind of reminds me of sleet.

    • nsbfdarlene@aol.com says:

      Yes, to look at it on surfaces, I would say you are right. But what is falling doesn’t look like sleet.I actually expected to find a glaze on things because I thought it was freezing rain. Hmmm…maybe it is what others have been calling snizzle today.

  9. muxpux says:

    sounds like this is gonna be a fun one….

    FRONTAL PASSAGE EXPECTED AROUND 15Z MONDAY AT PORTLAND. THIS IS A
    VERY IMPRESSIVE COLD FRONT WITH A SHARP FRONTAL TROUGH SEEN IN THE
    NAM WHICH SHOWS A 6 DEGREE TEMPERATURE DROP IN ONE HOUR AS THE FRONT
    PASSES. I AM ALSO CONCERNED THAT THE NAM IS SHOWING A LOT OF
    PRECIPITATION BEHIND THE SLOPING FRONTAL SURFACE WHERE WARM
    ADVECTION IS CUT OFF AND CAN NO LONGER COUNTERACT THE COOLING
    EFFECTS OF SNOW FALLING INTO THE WARMER SHALLOW BOUNDARY LAYER. THIS
    SITUATION DOESNT HAPPEN HERE VERY OFTEN…BUT IF THE PRECIPITATION
    RATES ARE HIGH ENOUGH THIS HAS THE POTENTIAL TO DRIVE THE SNOW LEVEL
    DOWN TO NEAR THE VALLEY FLOOR IN THE NORTH MONDAY MORNING WHICH
    WOULD BE RIGHT DURING THE MORNING COMMUTE. WE WILL HAVE TO WATCH FOR
    THIS AND SEE IF THE MODELS CONTINUE TO INDICATE THIS POSSIBILITY
    OVER THE NEXT 36 HOURS.

    • Laura (West Gresham) says:

      yea, i just read the discussion.. sounds like could be an interesting few days for us here.. 😮

    • Rob "Wrath" S.E. Portland says:

      My folks are supposed to go to Lincoln City Monday Morning…. Ugh. Ah well it’s only 750′ over highway 18 I believe.

  10. Can you say windstorm? GFS is SICK

  11. Thee Lazy Cat says:

    Snowing in manzanita Oregon

  12. Benjamin (West Salem) says:

    Do you guys see a chance for snow here in Salem on Monday? It looks like a cold rain, but that is just my thought.

  13. Andrew Johnson says:

    I’m hoping that low trends south and comes onshore around Waldport and tracks NE.

    • Rob "Wrath" S.E. Portland says:

      O…


      A lot of potential.

    • Copper says:

      What would that mean? Another snow event?

    • Rob "Wrath" S.E. Portland says:

      I would doubt it I don’t think there would be enough cold/modified arctic air even if a good east wind were to develop. The thing you have to watch for with a strengthening low coming up from the south like this is a south wind event/storm.

    • Andrew Johnson says:

      By potential I hope you mean to take the track I mentioned leaving us on the cold side of the low with heavy precip dragging snow levels to the surface!

    • Rob "Wrath" S.E. Portland says:

      1 AM Wednesday

      Already 988mb. Let’s see how much further it deepens over the next 4-6 frames and if the low becomes a bit more compact.

    • Copper says:

      I’d rather not have a windstorm unless it’s not too strong. 50 mph is my max lol!

    • Rob "Wrath" S.E. Portland says:

      4 AM Wednesday

      985mb. Gradient packing to the south of the low isn’t overly tight just yet.

    • Rob "Wrath" S.E. Portland says:

      Unfortunately on this path, trajectory, and due to the low still deepening there is no chance it would track inland south of PDX.

    • Rob "Wrath" S.E. Portland says:

      OH BOY!

      10 AM Wednesday

      Now down to 980mb moving northeast. Much sharper gradient packing now seen. Low is about to take a more northerly course. This gradient packing may swing right over the Willamette Valley.

    • Rob "Wrath" S.E. Portland says:

      1 PM Wednesday

      979mb due west of Astoria. Dangerous gradient packing has moved onto the Coast and is progressing into the Willamette Valley.

    • Rob "Wrath" S.E. Portland says:

      50kt gusts Willamette Valley. High winds imminent ON this particular model run.

    • Rob "Wrath" S.E. Portland says:

      Looking at the frames between 1-4 PM Wednesday and extrapolating the gradient packing I estimate a peak PDX-EUG of 12-14mb. Extremely dangerous.

    • Copper says:

      How high of winds would that be in the valley? I really don’t want this to materialize…

    • Rob "Wrath" S.E. Portland says:

      I would estimate gusts 55-70mph. If there is good mixing possibly stronger. We need to closely watch future runs(Primarily the 12Z/00Z WRF) to see how it handles this low especially if it deepens it further. It could do so, but just the same the low could be weaken or track differently in the days to come.

  14. Copper says:

    I was just outside and I’m not sure what’s falling from the sky sound like it was “crackling” as it hit the ground reminds me of the sound freezing rain makes when hitting a surface…but this isn’t an official report by any means. 31.7 degrees and the winds seemed to have switched to the east again that’s very interesting.

  15. muxpux says:

    http://wsdot.wa.gov/traffic/swcam.aspx?cam=8069

    the washington side of the astoria megler bridge, and it looks to be snowing at KM mountain. i cant help but to think all this will be reaching longview soon.

  16. geo says:

    Will this storm produce strong east winds or south winds. I’m worried about my roof.

  17. Camas_John500 says:

    Down to 28.4 here in Camas, but the light snow seems to have already turned into light sleet. Anyone else seeing that?

  18. light dusting starting now

  19. Rob "Wrath" S.E. Portland says:


    Uh oh

  20. Tyler in Battle Ground says:

    Astoria was 36 with snow, now 33 with rain, gotta love it!

  21. Josh (Gresham) says:

    Back down to 31.7 from 33.1 and the wind has switched from south at 5mph to east at 4 mph

  22. Max in Fairview says:

    Astoria back down to 34 temp, 32 dewpoint with light snow.

  23. Runrain says:

    Snowing in Happy Valley at 5 flakes/minute.

  24. Kyle says:

    Seriously: Is this a warm front or a cold front with chilly air behind it which will lead to another hard freeze?

    • jackfrost (beaverton) says:

      It’s a weird situation, warmer air coming from the north. There will be some areas below freezing in the morning but most of us should be in the mid thirties.

    • Weather Watcher says:

      It looks to me like we have a pretty good shot at some heavy wet snow early Monday morning as that heavier precip comes in pulling down the colder air to the surface- NAM backs this up quite nicely…

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