Snow & Freezing Rain In Gorge This Evening

10am Thursday…

As we say in the business, it looks like a “wintry mix” in the Columbia River Gorge this evening and overnight tonight.  But it’ll be a bit too warm for freezing rain here in the metro area and other areas west of the Cascades.

Here are the highlights:

  • A dry day today, even filtered sunshine through mid-afternoon.  Cold east wind continues pouring out of the Gorge.  Highs near 40.
  • Light rain should arrive during the evening commute, the big question is how light?  It might only be sprinkles, but more likely actual steady light rain.
  • Temperatures remain 35-38 degrees in the metro area while it’s raining, so no freezing rain for most of us here.  It might drop to just around 32 on the hills in Troutdale or Gresham, so you might get ice on trees and objects, but slightly too warm for roads.  It’ll be very close temp-wise in those areas.  We’re talking only a degree or two from freezing.  Above freezing higher up, so no snow either.
  • It’ll be cold enough just east of Troutdale (Corbett, eastern Washougal hills, Bridal Veil, Mult. Falls) for this to fall as freezing rain.  That’s glaze ice; liquid rain freezes on contact.  Could even be ice pellets mixed in east of Bridal Veil.  Watch your driving!
  • Whatever does fall, light or not, will be snow from Bonneville Dam eastward in the Gorge.  Possibly 1-3″ in that area. Drier east of Hood River for just a trace to 1″ at The Dalles.  To avoid confusion, I mean all the way down to freeway level too.
  • The east wind will back off dramatically (just gusts 20-40 mph)  in the Gorge by late evening.
  • Mainly or all dry after midnight or so.

I just checked all the soundings, maps, models, observations etc…

East wind didn’t pick up much overnight, on that list of peak gusts from yesterday I notice only Vista House exceeded yesterday’s gusts.

A very deep and cold air mass is banked up against the Cascades, notice Meadows and Timberline even have the cold air “sloshing” up against the east side of the Cascades?  Timberline is 16 at 9am, it was 33 at the same time yesterday!  And in the Gorge is plenty cold up to around 4,000′, so between that and model soundings, it’s obvious it’ll be snow this evening in the central/eastern Gorge.  The air mass flowing through the Gorge won’t change today as a result, so it’s somewhat simple to figure out how far west the freezing rain could go.  Troutdale is running almost exactly the same temp/dewpoint as yesterday at this time.  Yesterday it was 35/21 during the evening commute.  Add precipitation to that and it’s a real borderline freezing rain event for them, more likely anywhere up in elevation or just to the east.  Once you get to Corbett or Mt. Zion areas, it’s an easy call.  Temps remain at or below freezing all day so any precipitation that falls will be freezing rain.  I’ll be driving the 4Runner to work this afternoon.

One big issues is moisture availability.  Our RPM (not always a stellar performer) is very dry with just a few hundredths of precipitation this evening. 

web_RPM_12z_Text_PDX_4km

If that’s the case, hardly anything interesting happens tonight.  The other models are a little wetter and I’ve based the forecast above on them.  We’ll see how that turns out; satellite imagery is definitely not very impressive.

Updates later in the day…

Chief Meteorologist Mark Nelsen

129 Responses to Snow & Freezing Rain In Gorge This Evening

  1. temp 37 here and were about to get slammed with a very heavy shower (showing red on radar) dew points in 23 already what looks to be a snow rain mix ahead of the heavy shower about to hit.

  2. Marcus says:

    I think it will be lower than that based on model runs they are not pulling the plug yet:)

  3. *BoringOregon* says:

    Go Ducks !! Kgw was saying 1000′ snow lev by the end of the 7 day?

  4. Ben T says:

    Does anyone else here use woeurope.eu for weather models?

  5. W7ENK says:

    Very light liquid water rain falling in Milwaukie, not freezing on contact, 37 degrees.

  6. KPTV Tower Temps
    http://www.wrh.noaa.gov/pqr/tower_temps/tower_temps.php?&units=F
    As of 4 PM (1 hour lag. Updates every :15 after the hour)
    Upper Sensor(1818′) 38.7 (33.6 at 3:00 PM)
    Middle Sensor(1473′) 31.5 (30.2 at 3:00 PM)
    Lower Sensor(1043′) 32.0 (32.2 at 3:00 PM)
    Uh oh….. :o. Enjoy your 9% chance of sleet or light sprinkles

    01z(5 PM) Upper Air Analysis(Observed over PDX)
    http://www.spc.noaa.gov/exper/mesoanalysis/new/viewsector.php?sector=11
    925mb: +2.3c
    850mb: +0.5c
    700mb: -7.2c
    500mb: -23.2c

    As of 5 PM
    PDX-DLS: -8.5mb | 4 PM: -8.3mb | Hourly Change: 0.1mb Increase
    TTD-DLS: -7.8mb | 4 PM: -8.4mb | Hourly Change: 0.6mb Decrease

    12z ECMWF Ensembles 500mb Height Anomalies
    6-10 day
    http://raleighwx.americanwx.com/models/ecmwfens/12zECMWFENS6-10day500mbHeightAnomalyNA.gif
    SCORE!

    My last post for awhile. Go DUCKS!

    • Ben T says:

      Wait, before you go. Were you talking about the Ducks scoring on a kickoff return? Or SCORE the chances of an Arctic Blast are looking better? I equal your sentiments, GO DUCKS! WTD!

    • Ben T says:

      -164 L! That’s cold lol.

  7. Brad says:

    Freezing ran/sleet in woodland

  8. alohabb says:

    Rob, might I suggest WPA for your habits?

    Weather Posters Annomous may cure your habit?!

  9. Marcus says:

    18z thoughts anyone!

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