It’s Christmas Eve! Silver Christmas For Parts of Metro Area

8:30am Sunday

For the first time in about 20 years I’m sitting here on Christmas Eve figuring out how a “classic” snow/ice event will proceed for the Portland metro area.

Of course in 2008 we had all the snow on the ground and expected a little more the next day, that was easy.  You have to go all the way back to 1998 to find a couple of inches of morning snow Christmas Eve; then it melted by evening as the cold east wind died.  This time it appears the cold air is here to stay THROUGH TONIGHT.  That’s a problem for many of us in the metro area and Gorge.  It’s also a change from my post 24 hours ago.

RIGHT NOW

A band of light precipitation is moving through the North Willamette Valley and into the south metro area.  It appears to be mainly rain/freezing rain with some sleet (ice pellets) mixed in.

Temperatures are near/below freezing throughout the metro, Willamette Valley, and of course in the Gorge.  A layer of cold/dry air pouring out of the Gorge is about 2,000′ thick in the metro and thinner south of us in the valley.  It’s a few degrees colder than I was expecting.  Where it is above freezing (by 1-4 degrees), the air is dry enough that when moisture falls into it, temperatures fall (evaporative cooling).  This means ANYONE could get frozen precipitation of some sort the next few hours from Longview to Salem/Albany.  This part of the forecast hasn’t changed.  We thought there would be scattered icy areas if/when that first band of precip arrives.

THE MAIN MESSAGE

Models are bringing in this afternoon/evening’s system a bit farther south, prolonging the period that at least 1/2 of the metro area will get freezing rain (and icy roads) the next 24 hours.  It appears more of the metro area will see freezing rain than I was thinking 24 hours ago.

WESTERN VALLEYS FORECAST HIGHLIGHTS

  • Oregon Coast will be too warm for frozen precipitation, all clear out there
  • After patchy areas of freezing rain this morning, some weak daytime “heating” in much of the Willamette Valley south of a Newberg-Wilsonville-Sandy line will be enough to keep roads mainly clear through tonight; temps will hover just above freezing.  AFTER late morning, most of the Willamette Valley should be done with icy roads.
  • IN the metro area the cold temps mean precipitation with this first band could ice up roads anywhere before noon.  As we go through midday and early afternoon, main roads should be fine away from the Gorge as pavement temperatures stay above freezing.  Near the Gorge and in the West Hills icy areas will stick around all day.
  • After sunset and into this evening, more solid precipitation arrives.  It should be mainly freezing rain across the entire eastern half of the metro area north of Oregon City and in the West Hills.  Expect widespread icy roads for all these areas through the night and into Christmas Morning.  A Silver Christmas for many of us tomorrow morning.
  • West of the West Hills and Clark County there may be more snow mixed in with slightly deeper cold air.  Temperatures may go a few notches above freezing.  Ice on roads should more patchy in those areas.
  • Christmas Day temperatures will gradually go above freezing and ice even near the Gorge will melt off.  High temps reach into the upper 30s.

IN THE GORGE

  • Light snow arrives midday, then picks up a bit this evening and overnight.
  • Expect 2-4″ fresh snow central/east Gorge
  • West of Multnomah Falls, it’ll be more freezing rain & sleet than snow.  Expect glaze ice on roads around Cape Horn and Corbett/Bridal Veil areas as we go into the overnight hours
  • Not much melting Christmas Day since cold easterly wind will just weaken a bit.

 

There are 2 reasons the forecast has changed back to more ice the past 24 hours.  First is that the cold air pouring through the Gorge is a few degrees colder than expected.  That gives more of us an “opportunity” to enjoy frozen precipitation.  And second, sure enough the ECMWF model is looking like the smarter one, bringing in low pressure farther south.  Check out morning WRF-GFS low position at 10pm this evening:

There it is…right around Tillamook.  This is far enough south to keep the cold easterly wind going in the metro area through the night.  But it’s also just far enough north to push mild air over the top of the cold air, that mostly eliminates the snow chances keeping our precipitation in mainly a liquid form.  Of course that liquid can refreeze into sleet (ice pellets) or freeze on contact (freezing rain).  Notice there is no southerly wind in the metro area even by 7am Christmas morning; temps will rise a couple of degrees in the valley overnight, but we’ll stay frozen through the entire night in that easterly flow out of the Gorge in the entire eastern half metro area.

Be careful on the roads today and if you live on the east side of the metro area I’d plan to stay at home this evening through Christmas morning.

Chief Meteorologist Mark Nelsen

113 Responses to It’s Christmas Eve! Silver Christmas For Parts of Metro Area

  1. Paul D says:

    So does this go down in the record books as a white Christmas for PDX?

  2. 2″ accumulation here near downtown St Helens

  3. 1.75″ accumulation so far (measured on my street in an spot that’s been shaded where the snow started sticking first). Most of that came from a snow band that tracked over me for the past 90 minutes or so. Looks like I’m in for a bit of a pause now before there will be any chances for more tonight.

  4. Ken in Wood Village says:

    What is going on with the NWS radar? it keeps going in an out all the time for the past few hours. (I roll my eyes…lol)

  5. WEATHERDAN says:

    31.7 at 6:45 PM. Mainly ZR but a little sleet mixing in at times. Temp got as high as 34 but has dropped below freezing. So much for the low coming in to the North of us. May see more snow or ZR Tuesday night. Merry Christmas.

  6. Nahtalkin says:

    Snow ended for now about a half of an inch, 31 degrees.

  7. Ken in Wood Village says:

    The city of Wood Village closed 238th going up the hill next to were I live. They normally close this road during the winter when we have either snow or FZ. Dave from Channel 2 was doing a live broadcast when I showed up…lol

  8. Anonymous says:

    snowing in Wilsonville.

  9. Rivergrove says:

    Snowing heavily in Lake Grove!

  10. slaviklungu says:

    Howling winds out here in upper Troutdale at 26°F, gets tough to amount serious steady snow accumulation in comparison to places further west with less of the east wind. But if the snow keeps falling like it is currently, I predict we should have a classic whiteout Christmas Eve by 7 or 8 PM.

    BRING THE SNOW! sips on hot cocoa

  11. Longview 400 ft says:

    Currently 32.0
    1 3/4 on the ground,
    Some snow and sleet falling

  12. Nahtalkin says:

    Been hovering around freezing all day with on and off snow showers and now the temp. has dropped to 30 degrees and a heavy snow shower is passing through.

  13. Jason Hougak says:

    Snowing good in Barton at my inlaws. Anybody check out the radar, heavier yellow precipitation is starting to head into Clackamas county.

  14. chiefWright (Marquam, 375') says:

    Just got back from what we thought for sure would be snow in our foothills above Silverton. Started out here 450′ 31 degF, low cloud. Got into fog about 800′, broke out below light stratus at 1500′, and temp jumped to almost 40 degF! Got into slushy/icy snow about 2000′, still about 40 degF.
    Now back home to 32 degF light rain 4 mph NNW. Think we’re going to have the usual Grey Christmas…

  15. Gene says:

    Snowing hard out in east Gresham — temperature at 26 and holding at my location, and the East Winds are howling. It’s a White Christmas Eve, for sure!

  16. ocpaul says:

    ZR in OC 31.6 oh well

  17. Ken in Wood Village says:

    It’s snowing so hard that a hill which is about 2 blocks away is hard to see it now 🙂

  18. cgavic says:

    sandy snow…..one to two inches. heavy snow showers have returned this evening.

  19. Snowing and sticking. Started at about 15:30 here. Was out riding my bike along a beach road and noticed I couldn’t see across the Salish Sea to Seattle. Then noticed the next point south of me on the island starting to get hazy, and could see it coming across the water to me. Decided stay and watch it come. Once it came, it wasted very little time in starting to stick. Even starting to stick to the roads in the spots that have been mostly in the shade the past few days.

    Surprisingly, it started as snow, so far as I could tell, despite my 15:00 temperature reading of 38˚F and a freezing level of 3000 feet. Shows what evaporative cooling can do when the dew point is below 20˚F.

    • The other thing I must mention is thet the models were astoundingly accurate as far as precipitation onset time for my location. Even on Friday the model consensus was 16:00. To only be off by 30 minutes is quite impressive in my book.

  20. Alohabb says:

    Temp down to 29 and sleet freezing rain im Aloha.

  21. Terri says:

    Well there is an easy way to forecast the weather…. Actually go outside and check it out, instead of sitting on your butt reading what you’ve programmed a computer to tell. Just a thought.

  22. Mid-valley has the heaviest precip. If only that blob was up in the metro.

  23. Max in Fairview says:

    Heaviest snow of the day coming down

  24. Hazel Dell Mole says:

    Stuck in a well shook up snow globe way up here in Ha-Ha-Hazel Dell

  25. Angie80 says:

    Any theories on how the morning holiday commute will look? Around cowlitz county.

  26. Ken in Wood Village says:

    LOL, the NWS just changed what I’m suppose to have for the rest of the day into tonight. They had a wintry mix with FZ but now it’s just all snow with up to 3″ of snow…LOL. Love it 🙂

  27. JohnD says:

    Getting really dark out with thickening clouds now here in inner SWPDX. Barometric pressure falling. Temp now at 29.4–coldest so far today. Yes I am pumped! What a treat for Cheistmas Eve!!

  28. Lee Wilson says:

    Merry Christmas Eve to you 🙂
    Recorded using the PS4 so not the best camera.
    But, it will do.

  29. Ken in Wood Village says:

    It’s starting to snow again, can I get a woot woot 🙂

  30. Garrison - Christian says:

    Ice pellets and 32F here in Aumsville oregon 375ft. (10 miles SE of Salem)

  31. Most importantly it is 100% snow right now.

  32. Longview 400 ft says:

    Currently 32.0
    One inch of the white stuff on the ground.
    Still snowing quite nicely!!!!

  33. Starting to snow again here in Vancouver near Van Mall & 205.

  34. Anonymouse says:

    Sleet with snow flakes mixed in starting again in SE, much earlier than expected. Forecasts are all over the place, one says it should be 35 and raining by now and another said the whole 3 o’clock hour would be dry. Definitely interesting to see this play out, wonder if we will get all snow.

  35. Alohabb says:

    Light snow falling now in Aloha

  36. Ken in Wood Village says:

    The radar is filling in nicely. Just hoping I will get more snow when it hits. Last time I checked for the Troutdale airport, it was 30F and the DP was back down to 23F from 25F. Hopefully the temp will drop some and I’ll just get snow. Don’t really like the FZ stuff…lol

    • As long as the gradient doesn’t start slacking off and we get moderate steady moisture I’d guess it would fall as a snow/sleet mix here in Vancouver.

      • Ken in Wood Village says:

        I was thinking the same thing. By what I see with the radar, there is a good amount of moisture coming. One thing that helped with the first round was it started out as snow, maybe it will do it again but I don’t think it will…lol

  37. Andy says:

    At 2:30 35 deg and slushy rain here in Albany,OR. Hoping the temp drops, but I doubt it will do anything south of Portland. Lots of winter to go.

  38. PDX to DLS pressure gradient was still increasing as of 1pm but the 2pm noted the difference is steady now. Hope that doesn’t start falling off.

  39. Snow has made it to Olympia (actually made it there a good quarter-hour ago, judging by webcams).

  40. Anonymous says:

    PDX to DLS pressure gradient is still increasing as of 1pm as well.

  41. F40 Fan says:

    This site is certainly more accurate than the TV bobbleheads… The blond weather girl on 12 and the amazon on 6 are completely worthless.

    • Nahtalkin says:

      Thanks for saying that so I didn’t have to.

      • F40 Fan says:

        The blond on 12 is much more interested in posting selfiesm her food choices and getting her ego stroked by lonely men on facebook who think they have a shot of being Mr Right….

        • Nahtalkin says:

          I think maybe she’s not really real…..maybe robotics in action….saves the company tons of moolah. Listen to the voice maybe an automaton.

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