Snow Chance For Friday Increasing

10:30pm Wednesday…

Models have speeded up the timing of the return of moisture Friday morning.  What does that mean?



Our RPM model has actually backed off a bit on possible snowfall at that time, showing just about everything north and east of the metro area.  However the UW-WRFGFS model has painted a larger area of snowfall over us sometime after 2am Friday:


Notice the 2″ forecast for Scappoose, St. Helens, and most of central/north Clark County…more moisture available in those areas.  And if the faster timing continues in the next 2 model runs, just about all of it happens before the sun rises.  As a result it could be snowy morning commute across the far northern part of the metro area.

All models show a rapid warmup several thousand feet up after 7am now.  Snow can’t keep falling after that time for just about all areas.

We’ll be watching closely to see what tomorrow morning’s runs show.

Chief Meteorologist Mark Nelsen


65 Responses to Snow Chance For Friday Increasing

  1. Seahawks Fan - NE Vancouver says:

    100% snow and sticking to everything except the roads

  2. Slavic S. says:

    Living in portland for 25 years i believe this overnight event will be messier then we think

  3. boydo3 N Albany says:

    Don’t look at the 18Z new years day run (drool)

  4. Brandan says:

    37 degrees for an official high at PDX. Already down to 34 there.

  5. Sapo says:

    Temperature dropping like a rock in Tigard. We have gone from 39.9 to 34.7 in just 2 hours, and the temperature dropping speed is increasing.

    • Andrew (Beaverton, OR) says:

      Dropping fast here in Beaverton as well, down to 35 now. Snow is looking very likely in the early morning hours, maybe around an inch for PDX.

    • Sapo says:

      This is crazy, down from 34.7 to 33.4 in 10 minutes. We’ll probably make it down to 26 tonight because of cloud cover, but still. The rate of the dropping temperature is jaw-dropping. Any precipitation before 8 AM should be in the form of snow, so I’d say it’s a close call. We’ll wait for the new runs to come out tonight for more details on the specifics.

  6. Johnd says:

    As our emotions struggle to see even a wet snow
    shower that is gone in a hour I can’t help feeling
    lament about how close we came 2 weeks ago. Like
    Eugene: A FULL BLOWN winter event including nearly a
    foot of snow that lasted a week along with two nights
    below zero! Are you kidding?!We’d all STILL be jumping–probably like Paul still is! I haven’t
    given up hope yet though!

  7. Katrina says:

    Mark,please forgive me for mentioning this small thing, but just in case those graphics will be going on the broadcast later: “Affect” should be “effect.” (Will it affect the commute/ will it have an effect) 😉

    • marinersfan85 says:

      There should be a space. You wrote “Mark,please…” It should be Mark, (space) Please…. It would look like this. “Mark, please…” 😉

    • Model Rider says:

      Wow are you bored mariners fan. Wish we were all as smart as you. But I guess if I was a mariners fan I’d be bored all the time too.

    • marinersfan85 says:

      Oh so certain people can correct things but others can’t. Got it Mat. Yes, the Mariners suck, it’s no secret. I’m aware of it.

    • prairiedog says:

      Good grief Marinerfan, really? Her point was that the Affect/Effect was possibly going to be going on the air. Her point was valid and was just trying to be helpful. No real need for grammar cops for just blogging. Amazing. Tis the season I guess, people are easily irritated. Spread joy not discord.

    • marinersfan85 says:

      Oh, so we can only correct certain things. Got it. It’s good to know you guys have the rule book down pat.

  8. GoDucks says:

    Much about nothing. Now Seattle might see 3 snowflakes.

  9. WEATHERDAN says:

    Tis the season for model folly, la la la la, la la la la. Yes fellow bloggers it’s la la time again. Why because the latest GFS meteogram has a huge Arctic outbreak hitting the PNW about January 3rd 2014. Thickness at Vancouver B.C is down to 490. PDX is around 507. Soon we will hear the pitter patter of the little model rider feet and shouting it’s going it’s going to snow. Bah humbug. I wish it would come true I really do. I just don’t believe it. You know the old saying 1,472 time burned twice shy. If this trend is still there next week then we shall see. Also for those riders out there in blogger land the 12z GFS paints a picture of mainly N to NW flow out to hour 384. Sometimes even backing off to the NE at times. And from reading the posts today there is a chance of some cold weather around Christmas. What I don’t see is a strong Westerly flow with a lot of mountain snow. If we go another 6 weeks in this pattern we are in big trouble for next summer. In the meantime enjoy the sunshine. Peace.

  10. Aloha Rainshadow says:

    I would actually take Mark’s graphic and cut those percentages in half…put the “snow day” to 1%

  11. Rob - Southeast Portland says:

    Yeah, 12z WRF was definitely a step in the wrong direction if you want Snow in PDX. The 4km Sounding was very telling. It featured a large dry layer aloft from 950-850mb and takes too long to saturate the air mass while the column is below freezing. Another issue is there is no aid in east wind, in fact, there is none. The gradient is light westerly through the Gorge ahead of the moisture, that’s NEVER a good thing. Another problem is it appears clouds will thicken up early evening not allowing for little if any appreciable cooling overnight. IR Loop verifies this too. I think maybe Wet Snow briefly in PDX or Sleet. Best Snow chances are north of the Columbia River into Clark County where they might see a dusting to 1″. Pretty much a non-story. Let’s move on and focus on the 500mb pattern after day 8. I see some very slight glimmers of hope.

  12. Garron near Washington Square says:

    I’ll be taking a trip tomorrow morning! Want to see the falls, might swing across the bridge to see what accumulating snow looks like if this thing comes in @ the right time. Incidentally. I’ve noticed quite a bit of ponds, HIO slough still frozen from the week before. Hoping the falls still got some ice to ’em.

  13. Heatblizzard says:

    Even though it doesn’t effect me fro the first time of the winter season Silver Falls School District is on a *late start* due to icy streets.

    Not once during the entire cold spell earlier in the month did the schools run late except for Victor Point Elementary which is like almost 1,000 feet on a hill.

  14. Aloha Rainshadow says:

    12z WRF poops on PDX snow chances.

    • Sapo says:

      Yeah, the 12z WRF is absolutely horrible. Hopefully it’s an outlier run.

    • runtmc says:

      I wish you wouldn’t have used the term “outlier.” It’s just an invitation for W7 to chime in, chest all puffed out, with some condescending retort about how delusional you are to think such a thing. Remember, he’s seen this all before.

    • Aloha Rainshadow says:

      Technically the soundings show no snow for PDX. Leads me to believe that if anything white falls from the sky it will be very brief and won’t amount to much. Soundings say the warm air works in above the surface before the moisture even makes it to the ground in PDX.

    • Benjamin (West Salem) says:

      Unfortunately it isn’t looking very likely at all for snow chances in Portland this time around. Looks like in general a Seattle northward event.

    • marinersfan85 says:

      I’d like to know how runtmc’s comment isn’t a trolling attempt? I thought there were rules against it and yet it’s OK for people to make a trolling comment like that? Erik doesn’t troll FYI. Share’s his opinion. You alljust don’t like it, that’s why you all think he trolls.

    • Aloha Rainshadow says:

      Mariner, unfortunately Erik’s reputation precedes him, even though he may not be trolling, obviously there is an impression that is what he does. He adds flavor to the comments even though I don’t always agree with what he says and how he says them. I find him entertaining. He is knowledgable about the weather. It’s just in the way he says things or conveys his message…that can appear trollish…and he does come off as negative a lot of the time.
      Run’s comment is not necessarily trolling, he’s sharing his opinion…can’t judge one way and not the other 🙂

    • runtmc says:

      My apologies. Strike that from the record. I really love this blog, particularly reading Mark’s insight and the exploration of all the possibilities–no matter how outlandish (Kenny) they might be–that the models suggest. The “facepalming”, the grammar policing, the tirades about “1st” comments, the belittling of people who are simply saying, “Hey, it’s a longshot, but let’s still talk about it.”–it’s all a little off-putting to me. But, hey, he’s got some weather knowledge and I don’t. So I need to just enjoy from the sidelines without comment, carefully avert my eyes whenever I see “W7ENK”, and continue to enjoy all of the unique insight on this great forum.

    • Sifton says:

      Hey run, every blog needs a self appointed moderator (aka: W7) & I LOVE me some Kenny too, even more now than JJ’s run on sentences from various other time zones!!

    • W7ENK says:

      Really, why you gotta play me like this all the time McRunt? The subject of the vast majority of my comments here has always been, and will continue to be the weather. Yours, on the other hand, always seem to be, well, me. Obsess much? Flattering, but also awkward.

      I don’t belittle people. I don’t go out of my way to call people out. My red pen rarely ever leaves my pocket, and never once have I puffed my chest and declared “I told you so!” That just ain’t my jam. But I joke, A LOT. I’m a freaking clown! (not really, clowns are creepy) Learn to deal with it. It’s the internet for God’s sake, why so serious?

      :mrgreen: 😆 😉 😛 😀 ❗ ❗ ❗ 😕

    • GTS1K' says:

      …said the Eddie Haskell of the Blog.

  15. gidrons says:

    We had one really brief snow shower last evening and that was it, in the hills above Scappoose. The kid’s snowman is looking anorexic. The snow tonight will come just in time to save him.

  16. JohnD says:

    Would someone care to comment on a compelling segment
    from this mornings Portland NOAA AFD “LONG TERM”

    • gidrons says:

      It shows a weak storm riding over the ridge coming in from the NW. 850mb temps around -4 to -6c. It would give light snow in the hills. Anything lower would depend on timing. Still too many variables to get excited.

  17. Andrew (Beaverton, OR) says:

    Down to 23 at the Hillsboro airport now, impressive.

    • David B. says:

      Not nearly so cold here in the Puget Sound region, but dew points are nice and low now, mostly in the low 20s.

  18. W7ENK says:

    You’re just bound and determined to prove me wrong, Mark!

    I still think this will be an exclusively North of the Columbia River kind of deal, like so many other these past 5 years. Snowflakes in the air, sure, but nothing of consequence this side of the creek. Of course the airport/NWS office will record a solid inch just to skew the official records, but this is primarily going to be a 37 degree rain only event South of Foster Road. The Dome is strong with this one!!

    BTW, with all the reports of icy roads this morning, Milwaukie has 34 degrees and wet roads. No ice whatsoever.

  19. Andrew (Beaverton, OR) says:

    Side streets off of Murray near highway 26 were a mess this morning, murray was icy on the sides but not bad overall. HIghway 26 was clear along with downtown.

  20. marinersfan85 says:

    It’s been icy on roads and everything else since 9pm here. 26.8

  21. well i didnt see them fall but there are snowflakes on the frozen cars. you can count em, haha

  22. schmit44 says:

    12/18/2013 Oregon (All) Temperature Summary

    High:54 at RED MOUND(1753 ft) & Yaquina Bridge W(120 ft)
    Low: 41 at CW5925 Coos Bay(49 ft)

    High:18 at NYSSA(2172 ft)
    Low: 3 at Lakeview, Lake C (4734 ft )

    Largest Diurnal Change: 36 degrees
    RED BUTTE (43/7 ) (4460 ft )
    Lakeview, Lake C (39/3) (4734 ft)

    Heaviest Rainfall:
    0.21″ at WH6KO St Helens(79ft)

  23. David B. says:

    Bellingham is 35 with a dew point of 20 and N/NE winds. Northerly breeze is picking up here. Looks like the Fraser outflow is underway. Let’s get those dew points niiiice and low to maximize evaporative cooling tomorrow night.

  24. Ben T says:

    GOLU model will be put to use tomorrow night!

  25. pappoose in scappoose says:

    2″ works for me!

  26. Tyler Mode in Battle Ground says:

    I’ll take a brief snow! Better than nothing!

  27. pappoose in scappoose says:

    Who’s on first?

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