A Very Wet Weekend Ahead

7pm Thursday

It’s been a classic wet Pacific Northwest day.  It’s not like we’ve seen massive downpours, but it rained just about every hour of the day.  Expect the same tomorrow as waves of showers move inland behind today’s cold front.  One difference tomorrow is that we’ll see sunbreaks between the showers; it won’t be such a gloomy day.

But this weekend is a bit different.  All models forecast an “atmospheric river” (another name for a Pineapple Express) aimed somewhere near the Oregon/Washington border from Saturday through midday Sunday.

GFS Water Vapor

GFS Water Vapor2

I’m very confident it’ll be aimed somewhere within 100 miles north or south of that spot, but exact location of the deepest subtropical moisture is critical in determining how much rain any one part of our region gets.  As always the heaviest rain will be in the Coast Range and Cascades.  Models are in pretty good agreement that this is going to be a very wet event.  They have consistently been forecasting 8-10″ (or a little more) in the usual wettest mountain locations.  Here is the morning ECMWF rain forecast:

ECMWF Precipitation Accumulation

Once again (for maybe the 4th-5th day) it’s showing a maximum of 10″ or more in those usual extremely wet spots.  That would include a few of the western Coast Range slopes and SW Washington Cascades.

If we indeed do see 3″ of rain from Saturday morning through Sunday midday, I think we could get some urban & creek flooding.  Especially Saturday night and Sunday morning since precipitation intensity appears to be highest during that time.  So keep a close eye on the forecast this weekend!

By the way, I just noticed snow has begun sticking at 5,000′ on our Skibowl camera.  The snow level drops to Government Camp by morning and stays there through Saturday morning.  By the time the snow has changed to heavy rain late Saturday morning we will have seen another nice dumping on the mountain

Snow MtHood Outlook

Much of that will be washed away later Saturday and Sunday of course so this sure won’t mean an October start to the ski season.  But it’s always nice to see early snow.

Chief Meteorologist Mark Nelsen

15 Responses to A Very Wet Weekend Ahead

  1. ocpaul says:

    All of this rain and wind sounds bad for the gorge.

    • Nahtalkin says:

      Actually it is neither good nor bad……weather has been happening since time immemorial, or as my good friend Heraclitus of Ephesus once said “the only thing constant is change”. Someday soon folks will be laughing at the quaint little phones we now adore and the infernal combustion engine we all love to hear purring in our escapades.

  2. W7ENK says:

    INCOMING!!

    Hard to tell, but I think I’m hearing some thunder… 🤔

  3. WEATHERDAN says:

    1-2 inches of rain in Central Valley this weekend. Maybe 3 or 4 in SW WA. Next week sounding dryer and warmer. Now sunny and 50. Peace.

  4. W7ENK says:

    Wind gusts to 45 mph, Portland metro, Saturday afternoon through Saturday night.

    https://inws.ncep.noaa.gov/a/a.php?i=16553825

  5. JERAT416 says:

    If only the snow level was at 3,000ft the whole time…..

  6. Roland Derksen says:

    Reminds me somewhat of mid-october 2003, though I doubt I’ll see anywhere as much rain here as we had that time.

  7. W7ENK says:

    So, upwards of 4-1/2+ inches of rainfall in roughly 36 hours?

    Good Lord!! 😱

    Not to mention the heavier rain amounts in the mountains, AFTER they receive a foot or two of new snow. All that snow (and then some) will be quickly melting and washing down into the lowlands. So yeah, there’ll be some flooding for sure, no kidding! Sandy River, White River, Hood River, Clackamas River, etc… could be a rough go by Sunday night.

    • Jason Hougak says:

      There is only a decent amount of snow at 5K and above. Only spots of concern would be drainages of Mt. Hood and other Cascade Peaks.

  8. Jason Hougak says:

    Too bad this event over the weekend is subtropical and we are getting a nice dumping of snow before the event instead of after.

  9. Paul D says:

    Time to attach the pontoons to my car 🙂

  10. Joshua Downtown PDX says:

    Bring it!!! Although, I will be in North-Central Cali. Shame I am going to miss the deluge. Enjoy, fellow weather lovers.

  11. JohnD says:

    1st? Awesome early season stuff! Couldn’t help but notice the early NOAA expectation for the season here too. Could be another interesting winter!(?)

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