Saturday Forecast Looks Drier Here: But Heavy Rain Up North

9pm Thursday…

An interesting turn of events for this weekend; all models are keeping just about all rain out of the Willamette Valley and Clark County through Saturday afternoon.  I’m REALLY glad I didn’t make a big deal out of Saturday’s rain…whew!  It will eventually rain Saturday evening, but nothing too unusual.  Here’s the rain forecast for the next 48 hours from the evening UW-WRF model:

00zwrf_48hrprecipsatpm

and the evening NAM-MM5 from the UW:

00zNAM_24hrSaturdaypm

Not much rain through Saturday afternoon here…

Why the change?  It’s somewhat related to my weekend plans; I have a long weekend planned in Southern California.  Over the last few days I’ve been watching the maps for down there pretty closely and each day models have been digging our system farther and farther south.  At one point it looked like 80 degrees where I’m heading Monday and Tuesday.  Not it looks to be around 65.  The point is the southern part of this system is showing more and more energy and now we see that stalls the northern portion late Friday-Saturday.  The weak split can be seen in the 500mb chart for Saturday afternoon:

gfs_500mb

This may (or may not) be the beginning of a splitty winter pattern we would expect in a strong El Nino year.  We’ve seen this happen a few times in the past few weeks (the splitting) and it really shows up again on tonight’s GFS run.  That said, it IS the GFS…

A surface low even develops off the southern Oregon coast with this splitting.  As a result, rain totals by Sunday afternoon look very heavy from around the mouth of the Columbia River up into SW Washington north of Longview.  Watch out on the Chehalis River!  The Portland NWS has just issued a Flood Watch for that area in yellow.

RPM_RAIN_NWOREGON (1)

Note nothing too excessive south of the Columbia inland…maybe an inch or so in Portland.

For skiers, the good news is the snow changing to rain right now will let up and it’ll be mainly dry up there through Saturday.  Then a decent dump Saturday night and Sunday.  I’m thinking 6-10″ is likely at Government Camp by Monday morning.  Higher up additional snow will fall Monday before snow levels take a huge jump Tuesday.

Looking farther ahead models are a bit of a mess.  ECMWF and earlier runs of the GFS were very wet Tuesday-Wednesday with a ton of snow in the Cascades Wednesday.  This evening’s GFS has much more ridging and casts doubt on that snow forecast…we’ll see.

And a sure sign winter is almost here!

The 18z GFS gave us the first model forecast of an arctic blast.  There will be many more teases like this through February.  It showed a massive plunge of cold air (some snow to sea level too) the day before Thanksgiving.  Temps probably 25 degrees in the metro area on Thanksgiving Day for a high.  But, the next run has nothing of the sort…easy come, easy go!  Time to get your tickets and board the WishCast Express…

WishcastingExpress

40 Responses to Saturday Forecast Looks Drier Here: But Heavy Rain Up North

  1. schmit44 says:

    11/13/2015 Oregon (All) Temperature Summary

    Warmest:
    High:68 at DW7237 Pendleton(1188 ft) & ECHO(758 ft)
    Low: 57 at K7FU Warrenton(33 ft)

    Coldest:
    High:33 at Mt Hood Meadows(7300 ft)
    Low: 18 at Lorella (4160 ft )

    Largest Diurnal Change: 40 degrees
    Lorella (58/18 ) (4160 ft )

    Heaviest Rainfall:
    3.97″ at HEBOWX Mt. Hebo(3160ft)
    3.34″ at CEDAR(2220ft)
    2.95″ at Timberline Lodge(5880ft)
    2.83″ at TIDEWATER(2035ft)
    2.74″ at SOUTH FORK(2257ft)
    2.58″ at MEARES Cape Mear(1421ft)
    2.56″ at Mt Hood Meadows(5380ft)
    2.53″ at Astoria Regional(10ft)

  2. WEATHERDAN says:

    Most of the leaves that were covering my front lawn yesterday are now covering the yard across the street thanks to a good strong South wind. When my Grandfather was asked many years ago why he didn’t rake the leaves off of his lawn in the Autumn he replied. God put the leaves on the lawn and God will take them away. I like that attitude. 58 and cloudy and windy at 1:30 PM. .14 so far today. Triskadecaphobia anyone. Peace.

    • Triskaidekaphobia. Words of Greek origin typically use a ‘k’ instead of a ‘c’. OK, enough spelling lessons, back to weather: rain has slacked off up this way. Had .72″ in the gauge this morning. Will be interesting to see how much fell today.

    • Joshua Downtown PDX says:

      So, you’re saying there’s a chance? Haha, yea right. I like the coast range has no chance, but Portland does. Meanwhile… it’s a balmy 57 degrees and bone dry out.

    • “I like the coast range has no chance, but Portland does.”

      Mostly just an artifact of the coarse model resolution. No place in the lowlands has much of a chance.

    • W7ENK says:

      Replace “much of a” with “any”, and I’d be inclined to agree with you!

  3. runrain says:

    The Dome is exerting monumental force today. It may lose the battle eventually but the radar loop clearly shows its attempt to keep the heavy rain to the north. Has to be the Dome. No one does it better!

  4. Rain has been coming down in buckets for the past hour or so in downtown Seattle. Atmospheric river is here.

    • Dave in South Salem (500') says:

      The US Drought monitor might upgrade western Washington to only moderate drought if this keeps up.

  5. () says:

    Is this really a surprise to anybody? They always overplay the big rain event and in reality nothing hardly ever pans out.

  6. Interesting ride to work this morning. Been a while since the Sound was rough enough for waves to be going WHAM! against the hull of the ferry and making it shudder.

  7. W7ENK says:

    It’s nice to see the Wishcasting Train building up a full head of steam! Like always, it’s going to be a long and bumpy ride…

  8. Chris s says:

    The setup this coming Sunday looks very interesting… Snow levels are gonna fall fairly rapidly… Maybe to quite a bit lower than what most are thinking??

  9. Joshua Downtown PDX says:

    So, our “wet and cool” start to November has actually been both drier and warmer than normal. The warmer part will be a quickly increasing anomaly over the coming days. We may get to near normal precipitation by mid next week, but that is unlikely with a defecit already and average daily totals of around .20″ this time of year.

    • Joshua Downtown PDX says:

      Mark, what’s up with the 12z RPM giving us 1″ of rain late tonight/early tomorrow morning? Are you buying that? I believe we will get maybe .50″ when the main rain band orients itself north-south later on Saturday evening.

  10. Close to 3 inches of rain have fallen here(Vancouver,BC) since 5am yesterday morning, and now it appears to be winding down. I’m going to count how much of an amount I have for the first half of the month on the 16th. It’s too early to make a prediction yet, but if these conditions continue, we could make a run for November 2006 for the wettest November on record. But we’ll see!

  11. Speaking of wishcasting….the last 2 runs of the ECMWF have brought a glancing blow of chilly air to the Pacific Northwest, even if it isn’t a full-blown arctic blast.

    • Mark Nelsen says:

      I agree, looking like we’re getting close to December weatherwise with some of those troughs. Time is flying…wasn’t it just Labor Day? Must be an age thing.

  12. schmit44 says:

    11/12/2015 Oregon (All) Temperature Summary

    Warmest:
    High:59 at Gold Beach (US 1( 60 ft)
    Low: 45 at BROOKINGS(79 ft) & OCNSID Oceanside(22 ft) & ROCKWY Rockaway(450 ft)

    Coldest:
    High:26 at HARL BUTTE(6071 ft) & ALAKES Haines(7979 ft)
    Low: 12 at DIMLKE (4726 ft )

    Largest Diurnal Change: 39 degrees
    Horse Ridge (US (52/13 ) (4160 ft )

    Heaviest Rainfall:
    1.02″ at SOUTH FORK(2257ft)
    0.85″ at HEBOWX Mt. Hebo(3160ft)
    0.81″ at Timberline Lodge(5880ft)
    0.75″ at RYE MOUNTAIN(2000ft)
    0.74″ at LOG CREEK(2800ft)
    0.71″ at CEDAR(2220ft)

  13. Dave in SW PDX (235') says:

    Hey save me a seat on that there WishCast Express – I have some frequent rider miles to use up before they expire.

  14. Paul D says:

    Does it go as fast as the Bullet Train? Count me in!

  15. pappoose in scappoose says:

    Ya, time to buckle up.
    Reach up there and pull them belts tight one more time!

  16. Mark bergal says:

    Who knows? Maybe the next run will be more confident on that arctic plunge. At least its getting interesting

  17. Sifton says:

    I’ll take 1 round trip in coach please for a repeat of winter 2014-15!! But of course with more snow above 4,500 ft or so.
    (Also ANY snow in the valley would be great too)

  18. timbers15 says:

    I like your train! Very futuristic.

  19. Big Nel says:

    Headed for Reno tomorrow 11/13/15, then phoenix by Monday via Vegas. Gonna run ahead of the storm I hope !

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