Columbia River Gorge Snow & Freezing Rain Wednesday Night

8pm Tuesday…

A chilly airmass is still sitting over Eastern Oregon below about 4,000′.  That cold pool of air continues to feed a gusty east wind through the Gorge.  You can see it in the cool colors on the 925mb WRF-GFS map:

s_slp.03.0000

The pressure gradient from The Dalles to Portland was up around 10 millibars earlier yesterday, but it’s down to around 7 right now.  The pressure difference directly impacts the wind speed out there.  This chart reads from right to left

pressure

Temperatures are within a few degrees of freezing from the Corbett & Mt. Pleasant areas in the western Gorge all the way to The Dalles.  So right now we are maybe 5 degrees colder than last week when we saw a dusting of snow above 500′ or so east of Cascade Locks.

Tonight and most of the daylight hours Wednesday we’ll be dry as a dying system moves overhead.  Sure, a few sprinkles west of the Cascades and a few flurries in the central/eastern Gorge, but that will be about it.

Tomorrow evening and night a wet system moves overhead.  The flow of cold air will actually INCREASE as a deep low pressure area moves towards the coastline; the strongest east wind of this event will be the result in and near the western Gorge.  At the same time precipitation arrives around sunset or just beyond and falls through that cold airmass.  It appears now that it’ll be mainly snow from around Bonneville Dam eastward.  A thinner layer of cold air from there to Corbett/Cape Horn areas means freezing rain & ice pellets are likely in the western Gorge.

There is not a huge amount of moisture available for a big snow/ice storm, but the best we’ve seen so far this season.  That doesn’t say much this year!  Here’s what I expect:

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SUMMARY

  • Roads may turn icy in these areas anytime after sunset Wednesday, soon after steady precipitation arrives.
  • I-84 will likely remain bare through this event up to at least Multnomah Falls.  Expect snow on the freeway (or at least slush) for the Thursday morning commute east of there to The Dalles.  By midday Thursday and beyond, the freeway should be clear since temperatures are not starting out as cold as they could be.
  • Expect some school closures/delays in the Columbia River Gorge Thursday morning
  • Additional precipitation later Thursday may fall as freezing rain in the Hood River and White Salmon valleys, but I doubt it’ll be cold enough for river-level highways (I-84 and SR14) to freeze up again.
  • Expect a cold and windy night in central/east metro Wednesday night, but temperatures remain in the upper 30s, no freezing rain or snow.

Chief Meteorologist Mark Nelsen

8 Responses to Columbia River Gorge Snow & Freezing Rain Wednesday Night

  1. Jason Hougak says:

    36.3F in Cascade Locks… hmmm???

  2. W7ENK says:

    Cool!!

  3. Low of 31˚F overnight. Yet another frosty night for me.

    • Roland Derksen says:

      A low of 29F here overnight- we had some high cloudiness through the late evening to just after midnight. Looking at the first half of January 2019, I see my precipitation total is 4.37 inches- just 0.03 inches less than the same period of January 2018. But I think we’ll see a lot less rain in the second half of the month this year.

  4. Kyle says:

    Charts? We don’t need no stinking charts! 🙂

  5. Ken in Wood Village says:

    Question to everyone. I was wondering if anyone has looked at ECMWF Deterministic East Pacific Oscillation? It’s been awhile but I thought we use to look at these charts? Also, I’m not sure if I’m looking at the right one to begin with…lol. Let me know what you think. Thank you

    • Kyle says:

      Charts? Who uses charts when models rule! The GFS is God! All must bow without question. LOL. Good question though. We also need to take in account PDO/PNA.etc

      Unless you have those kinds of indexes included in your East Pacific Oscillation already.

  6. Jason Hougak says:

    Epic Sierra snowstorm about to occur. Winter Storm Warning and Blizzard Warning posted. West slope Sierras 42-46” with possibility of 96” in local areas.

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