Heavy Cascade Snow Finally Arrives Tonight

November 27, 2016

8pm Sunday…

The long Thanksgiving Weekend is pretty much finished.  If you are STILL at your relative’s home?  Time to go home, they are most likely tired of you by now.  Plus they wanted to make more turkey sandwiches and you are gobbling up those precious leftovers.

The weather in the lowlands turned out about as expected with the big soaker on Thursday. Almost 2″ fell (in case you were out of town and didn’t get to experience it).

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Note how much wetter the past 6 days have been compared to the week leading up to it.  November’s rain total is now well above average…it has been a wet fall.  I missed it all since I drove with the family to the Reno area and back Wednesday through Saturday.  But oh that sunshine was nice!  Cold nights and comfortable afternoons.  Good enough for a Black Friday bike ride with nobody around

bike

We also drove through a brief dust storm in progress between Lakeview and Summer Lake, plus it’s so cool to see the huge clouds of alkali dust blowing off that lake too.

Now let’s talk about that snow forecast.  Early last week we were REALLY excited as models showed several systems coming in Wednesday-Sunday to bring 3-6 feet of snow in the Cascades.  By Tuesday evening, models were slowing down the Thursday system and digging more energy south into California later Thursday and Friday.  As a result, at 10pm that night I had this forecast for Mt. Hood:

marktuesdayforecast

You can see I lowered the numbers…thinking 2-3′ by late Monday when everything was done.  Marja lowered the numbers even further Wednesday night.  On the forecast I made Tuesday PM, for the Thanksgiving Weekend you get a forecast of 20″ at Government Camp (lowest number) to a 33″ for higher up at Timberline and Meadows.  Ooops…that’s not what happened.

Instead THIS is what we have seen…as of midday Sunday.  Only 3″ at Govy!

marksnow_mthood_totals

It was a GREAT weekend for travelling in the mountains since very little snow fell, totally different than what we were warning about Monday and Tuesday.  But for ski areas, it was an epic forecast fail.

What Happened?  It’s relatively simple…the upper-level trough moving into the Pacific Northwest slowed down Thursday-Saturday, keeping us in warm air longer.  It also stalled the surface front Thursday over the Coast/Coast Range/Western Willamette Valley.  Very little of ANYTHING fell on Thursday in the Cascades.  To the south they had more action than expected (as of Monday/Tuesday) in California.  Instead of several waves of moisture moving in from the west Thursday-Saturday, half the time the moisture was coming up from the south or southwest…hardly good for Cascade snow.  This illustrates why it is important to “stay on top of the latest forecast”.  I know it’s a cliche, but it’s true.  If you saw the forecast on Monday for many feet of snow, then didn’t pay attention to the gradually evolving forecast in the days following, you missed out.  I think by 10pm Wednesday our forecast was down to 1-3 feet of snow…a bit closer to reality in the end.

What you really want for big snow in the Cascades is strong westerly or northwesterly wind to ram into the mountains.  That is happening tonight.  So tonight is the big snow dump.

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I will be surprised if 10-12″ fresh snow is not on the ground at Government Camp by Tuesday morning.  15-20″ is more likely at Timberline and Mt. Hood Meadows.

Looking ahead…the weather this week looks quite benign.  Another weak system, but with that perfect northwest flow behind it, arrives Tuesday night.  That will bring another nice round of snow to the Cascades.  I expect mainly dry conditions Thursday and Friday as an upper-level ridge develops over the West Coast.

Temperatures remain near or just a bit above normal for the next 7 days.  December begins uneventfully.  But so did 2008, then we had our biggest snowstorm in 30 years just 2 weeks later!

Chief Meteorologist Mark Nelsen