Thursday Ice/Snow In Gorge Update

3pm Wednesday…

Here’s the note I just sent to the newsies…lots of uncertainty late tonight and tomorrow in the Gorge.


 

Easy forecast for lots of rain the next 36 hours, but Gorge forecast is very tough right now…a HUGE amount of uncertainty in what’s going to happen in the Gorge late tonight:

HIGHLIGHTS

  • For Thursday morning, heavy precipitation will be falling in the central/western Gorge, but both the NWS and we are unsure how much cold air will work into the Gorge during the night. Right now it’s in the 40s, but a wind switch should cool temps to around freezing by daybreak (didn’t mention evaporative cooling for the news people).
  • Assuming temperatures fall to freezing, precipitation type will be freezing rain in Corbett/Cape Horn/Multnomah Falls area transitioning to mainly snow from Cascade Locks to The Dalles. Amounts are very uncertain due to not knowing how cold it’s going to get.
  • Because of the uncertainty, the NWS has dropped Winter Storm Watch and converted to Winter Weather Advisory for most of the Gorge. The Hood River Valley is under a Winter Storm Warning due to a better chance for deeper/colder air there.

 

We get new model info between 7:30-9pm which should give us a better idea how cold it’ll be later tonight when the precipitation arrives.  Sorry to be so wishy-washy, but we don’t like to forecast a huge snow/ice storm when cold air hasn’t arrived and may/may not show up.

For west of the Cascades, lots of rain begins late this evening then continues all day tomorrow and into tomorrow night.  Expect 1.50-2.50” in the lowlands.  Enough for some rivers to return to flood stage and set off more mudslides.  At this time a widespread “Halloween-like” urban flooding event doesn’t seem likely since we don’t see tons of rain in just a couple hours.  More likely a steady moderate rain for 12-18 hours.

Chief Meteorologist Mark Nelsen

 

 

31 Responses to Thursday Ice/Snow In Gorge Update

  1. Mark bergal says:

    Following the latest storm, are there other juicy ones to follow or more showery colder systems? I have read Christmas could be either showery, rainy, or flirting with snow.

  2. Boring Oregon says:

    So I know Govy is supposedto get lots of snow tonight but how much of that will melt Thursday night?

  3. Already 33 here, and there’s a storm coming in. Hmmmm. Time to monitor ACARS and see what the aircraft soundings say.

    • It’s weird. There’s multiple freezing levels up there. It never gets very warm. Wind is forecast to be light easterly overnight. Surface temperatures in the region are mostly between 30 and 40 right now. I’m in one of the cooler spots but there’s spots cooler than me. Dew points are high.

      I’m wondering if I might be in for a “timing is everything” lowland snow event. That’s when a weak push of moisture (it’s going to be weak for me because the main force of the storm is going to hit you to the south in Oregon, again) comes in after a cold night without at most only gentle winds, so the cold air that formed doesn’t get blown away. Result is snow levels significantly lower than forecast.

      This doesn’t happen very often (in fact I’ve only seen it happen once in 20+ years), but it can happen and the way it’s so cold tonight as the clouds start to come in from an approaching storm does seem strangely familiar to that other time.

      This also doesn’t make for very significant snowfalls (it’s a weak push of moisture, afterall); in fact the one time it happened it was mainly just flakes in the air with a few places getting dustings on the lawns.

      But I wonder… could tonight be the night? At this stage I’ll give it a 1 out of 3 chance: probably won’t happen but still a very real chance it just might. If it happens, it will be spotty; some places will get mixed precipitation or cold rain. Time will tell.

    • froyobro says:

      What is your location?

    • flurball says:

      Fryobro good point. C’mon people. Give a location. You’re giving us football scores without the teams, George Carlin: tonights forecast……..mostly dark. Tomorrow morning…..turning a little bit lighter.

  4. Sapo says:

    We’ll see what happens tonight..current temps:
    43 at Hood River
    45 at Corbett
    44 at Cascade Locks
    41 at Bonneville
    39 in The Dalles (coldest temp I could find)

    That would be a pretty quick cooldown but it’s possible.

    • Dave in South Salem (500') says:

      Its clear and cold to the northeast from there. Hermiston and Yakima already below freezing. Pullman is in the teens.

    • Washougal 1100ft says:

      Weird 38 here west end of gorge with a east wind starting. Could get interesting?

  5. Sapo says:

    00z-18z GFS today have all been similar. GFS will probably change in two days, but since it’s around Christmas it’s worth speculating on.

    GFS says we could get a decent shot of cold air (not extremely cold, 850mb temps just about -6/-7c at best) sometime around Christmas. Doesn’t look like a ton of precip but looks like there could be some low snow levels with potential showers Christmas night or the 26th. Has some light precip/possible snow, it would only be about 1″ or so but who doesn’t want a surprise for Christmas! (or a day late)…

    It’s 9-10 days out so it will undoubtedly change but it’s fun for now!

  6. 18z GFS Ensembles definite improvement. I’d love to see the mean temp down to -8c by 00z tomorrow night.

  7. Washougal 1100ft says:

    East wind starting to blow!!

  8. marinersfan85 says:

    “We don’t like to forecast a huge snow/ice storm before the cold air arrives”.

    Hasn’t the forecast been a huge snow/ice storm for a couple/three days now?

  9. Sis Childs says:

    Mark – our elf came to my K-2 room today in Corbett just in case we miss school tomorrow. Also, my son Kevin’s house is the one on Corbett Hill Rd. The geoengineer says the house is sound but I sure am worried about more slides on Corbett Hill Rd. I don’t know how much more yard he can lose before the house isn’t fine anymore! What do you think?

    • Mark Nelsen says:

      Another week of rain sure isn’t going to be good. I wanted to buy that 10 years ago when it was for sale but my wife said she was worried about slides…so we didn’t.

  10. W7ENK says:

    SIGNIFICANT WIDESPREAD UNCERTAINTY WARNING
    NATIONAL WEATHER SERVICE PORTLAND OR
    301 PM PST WED DEC 16 2015

    ORZ001>014-WAZ019>023-039-040-202345-
    COLUMBIA RIVER GORGE- NORTH OREGON COAST- CENTRAL OREGON COAST- COAST RANGE OF NORTHWEST OREGON- CENTRAL COAST RANGE OF WESTERN OREGON- GREATER PORTLAND METRO AREA- CENTRAL WILLAMETTE VALLEY- SOUTH WILLAMETTE VALLEY- NORTHERN OREGON CASCADE FOOTHILLS- NORTHERN OREGON CASCADES- CASCADE FOOTHILLS IN LANE COUNTY- CASCADES IN LANE COUNTY- SOUTH WASHINGTON CASCADES- WILLAPA HILLS- SOUTH WASHINGTON COAST- I-5 CORRIDOR IN COWLITZ COUNTY- GREATER VANCOUVER AREA- SOUTH WASHINGTON CASCADE FOOTHILLS; INCLUDING THE CITIES OF… ASTORIA… CANNON BEACH… TILLAMOOK… LINCOLN CITY… NEWPORT… FLORENCE… VERNONIA… JEWELL… TRASK… GRANDE RONDE… TIDEWATER… SWISSHOME… ST. HELENS… CLATSKANIE… HILLSBORO… PORTLAND… TROUTDALE… GRESHAM… SALEM… MCMINNVILLE… DALLAS… EUGENE… SPRINGFIELD… CORVALLIS… ALBANY… HOOD RIVER… CORBETT… CASCADE LOCKS… MULTNOMAH FALLS… HOOD RIVER… THE DALLES… SANDY… SILVER FALLS STATE PARK… SWEET HOME… GOVERNMENT CAMP… DETROIT… SANTIAM PASS… VIDA… LOWELL… COTTAGE GROVE… MCKENZIE BRIDGE… OAKRIDGE… WILLAMETTE PASS… PARKDALE… ODELL… COLDWATER RIDGE VISITORS CENTER… MOUNT ST. HELENS… FRANCES… RYDERWOOD… RAYMOND… LONG BEACH… CATHLAMET… LONGVIEW… KELSO… CASTLE ROCK… STEVENSON… SKAMANIA… VANCOUVER… BATTLE GROUND… WASHOUGAL… TOUTLE… ARIEL… COUGAR

    https://www.dropbox.com/s/bug2bf1s47r8wd0/1%29%20NWS_SWUW.WAV?dl=0

  11. Thanks for the update. Definitely a lot of uncertainties and temps in the upper 30s to lower 40s across the Columbia Basin isn’t helping matters. Dewpoints are in the 10s and 20s though. PDX-DLS is now near -1mb which is right on par with the 12z WRF forecast, but it ramps up supposedly to -4mb by 7 PM. Maybe. Right now wet bulb cooling is going to have to work overtime assuming dewpoints/cooler air is pulled west. It just isn’t that cold 925s only -1c over Columbia Basin, 850s a bit better -5c. Tough forecast!

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