More Overnight Snow?

That was a fun little 1/2 hour snowstorm that moved through the metro area between 7-8pm.  Proves that precipitation intensity is often more important than the actual freezing level.  We watched the Sylvan ODOT camera (at 700′) for about 15 minutes and it went from bare to at least 1/2 inch with a snow-covered road in just that time.  Once the showers moved off to the north the roadway melted nicely.  Now it’s going to be dry until sometime late tonight.  With any clearing there will be quite a bit of ice on the roadways.
Quite a tricky forecast for the next 18 hours or so.  Beautiful wrapped up surface low has suddenly deepended west of Newport and at 8:30pm is out around 128W.  I noticed earlier today as the low passed near Buoy 46005, temperatures on the buoy dropped to the 36-38 degree range.  That is very cold for sitting on a little floating buoy in the middle of a 50 degree ocean. 
Both versions of the MM5 model now move the low a bit farther north as it moves inland tomorrow morning/midday.  They move it directly over Portland!  They also agree on a pretty good slug of precipitation beginning by 5-6 am at the latest, maybe by 3am.  If so, this could easily be snow since we have cool easterly flow moving out of the Gorge as the low approaches.  IF everything was perfect, we could get a 3-5" wet/heavy snowfall out of this for the morning commute down to the valley floor.  BUT, it looks slightly too warm for that.  So two thoughts stick out in my mind.
1.  With the low track farther north, sea-level or valley-floor snow is unlikely south of Portland and south of Tillamook.  Looks like Astoria-Tillamook and Longview-Portland is the most likely spot for significant snow down to the lowest elevations. Apparently this is the winter for coastal snowfall.
2.  That said, it is a bit warmer than I would like to see at the lowest levels to call for a snow storm in Portland.  And by that I mean by maybe only 2-3 degrees too warm.  It’s going to be close!

So….
Trace-2" possible at the lowest elevations from Chehalis to Wilsonville AND Tillamook north to Long Beach Peninsula
2-3" on the hills above 500′ and possibly at the coastline if the precip is heavy enough.
3-5" up around 1000′ or higher.
It’s quite possible that we have a messy morning commute coming.  A few inches at/above 500′ affects quite a few people.

Once the precip lets up around midday tomorrow, temps should rise up to the lower 40’s.  Then with stronger onshore flow Wednesday and Thursday AM, it’s unlikely that we’ll see significant snow to such a low elevation.  I think it’s possible this will be our last good threat for snow this season, since next week should be quite a bit milder…Mark

115 Responses to More Overnight Snow?

  1. winterhawk says:

    Great points Jerry!!!
    Actually, I think you’d made a backhanded comment at me last night in reference to me downplaying a previous event. Short term memory loss I guess. 🙂 You’re quickly becoming one of my favorites here!!! Lots of good scientific analysis, just minus the scientific analysis.

  2. timmy says:

    snowed here at pcc rock creek for a good 20 mins, now as it lightened up, its a light mix.

  3. kelly-clackamas says:

    Mom in law in Happy Valley reports that snow is falling, big flakes but not sticking to the ground so far. Here, I saw ONE flake fall here amoungst all the rain. Maybe 2. Getting windy here though.

  4. Weatherer says:

    I agree Rick…bring on spring and summer! Wonder what La Nina (if that does indeed pan out) has in store for us the rest of the year…should be interesting!

  5. Rick says:

    I am one of the ‘it’s going to snow’ guys here on the blog. Last night when it was snowing in Felida, I told my two sons, ‘if this were only happening a month ago…it’s just going to be too warm for it to stick this time around.’ The south wind never let up last night, in addition to it being March, you can’t have a south wind roaring at 20+ knots. Maybe in Chicago, not in Portland.
    I really appreciate everyone’s input and forecasts,YOU all do an excellent job, but the calendar won this time. Once the NWS posted the snow advisory, we were doomed:) Even our supreme leader, Mark, took a whack at it. The forecasts from all were a complete bust- even Winterhawk got into the melee, usually he is the cool head around here:) Put a fork in it, the fat lady is singing, turn out the lights….bring on spring. Who wants mixed snow and rain and 39 degrees?

  6. IceKeeg - Beaverton says:

    oh and that “700” is of course supposed to be the time 7:00am. I did not wake up 500 feet higher than my house’s elevation. ;o)

  7. IceKeeg - Beaverton says:

    Interesting borderline event so far. Looks like lots of moisture still and if that sustained precip keeps up, perhaps snow levels can make their way down yet. Happened last night.
    When I woke up at 700 it was mostly just rain as far as I could see – it’s been mixing here now at the 200 foot elevation of central Beav for the last hour or so and at times we get a good burst of mostly big flakes. Curious to see how this goes.
    Driving over the Sylvan to work should be great!

  8. Jerry says:

    Winterhawk- Whats funny is you werent speaking up last night… Mark seemed to think differently… This event isnt over, I never thought it was gonna be huge either, but when mark made that post it sure got me thinking. The models did do ok with this one.

  9. Weatherer says:

    Heavy rain/snow mix right now in NoPo (mostly huge flakes though).

  10. Tornado Aly says:

    Spoke too soon, a lot more mixing now. East wind may be helping!

  11. Tornady Aly says:

    Woohoo, I just counted 10 flakes mixed in with the rain!!!! Ha Ha Ha…

  12. kelly-clackamas says:

    😦
    dare I say, I’m a little bummed, not a flake to be found anywhere around here.

  13. winterhawk says:

    The models were actually right. I had seen this yesterday, but got ran out of town about mentioning it. The GFS staved the moisture off until later in the AM (just about now). The models also showed the clear jog to the north. The thing the models didn’t indicate was the amount of mixing which was going to occur. Winds are howling nicely here in the downslope areas of Clark County. Like I said last night, this was going to be one of those events that was just going to have to play out. Should still see some flakes, but this is a dud.

  14. ChuckyD81 says:

    Camas…
    Any accumulation out of that?
    Also…when did it start snowing most recently.
    Just trying to get a handle on the snowfall rates.

  15. timmy - scappoose says:

    mix here now

  16. Camas Mom says:

    STILL snowing! That band coming in looks SAWEET!

  17. Ryan (Da Couve) says:

    Well it appears the timing was off by mere hours for Vancouver. At least near the mall. I got some big flakes last night that covered the cars. Other than tha it was slushy-rain on the way in this morning.
    Looking at the current models it still seems to be calling for snow Thursday night (-9C with moisture). Me thinks after Thursday Night/Friday morning we begin our treck towards Spring.

  18. Weatherer says:

    LOL, gotcha. Well anyhow you’d be hard-pressed to find anyone in the immediate metro area with anything more than a flurry or two (below 500 feet of course).

  19. Ryan (Da Couve) says:

    Chucky – You can post on that thread as long as it is in regard to snow totals for your area.

  20. ChuckyD81 says:

    Weatherer…
    True…but you’re not allowed to chat there. I’m looking for more generalized information than what is supposed to be provided in that thread.
    Thus the reason I posted here.

  21. Weatherer says:

    Chucky, there is a seperate post for snow totals…you might want to check there.

  22. ChuckyD81 says:

    All…
    Wondering if everyone could chime in with their snowfall totals…if there are any.
    Total snowfall
    Snow on the ground
    etc..etc…
    Also if you have any significant MEASURED wind gusts…please let me know those as well!

  23. Austin Ridgefield says:

    It is all snow here in ridgefield I thought nothing was going to happen but know it, is the problem is I still have school see you all later guys.

  24. Camas Mom says:

    It’s getting pretty folks!

  25. Weatherer says:

    What a total bummer!

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