Bye Bye Snow!

November 1, 2010

Whew…it’s pouring on Mt. Hood and it’s in the mid 40s at the Ski Areas.   Heavy rain tonight (at least 1-2 inches), plus high temps in the 40-55 degree range the next 3 days should cut down the 18″  base at Mt. Hood Meadows and 24″ or so at Timberline to near the ground.  Such a thin snowpack doesn’t survive long under those conditions.  It wouldn’t be so bad if many feet were already on the ground.  Mt. Hood Meadows probably made a wise choice to not mess with just 2-3 days of skiing before shutting down for another week or more.  But this is how it goes, often even in a La Nina year.  Keep in mind that some of our best early season conditions have been during El Nino winters…then usually in December warmer and drier weather sets in; that happened last year.  It was a huge start and then yucky conditions for the rest of the season.  La Nina winters often ramp up slowly in the mountains then are excellent December-February.  This is opposite of what one would expect, but that’s what we’ve seen in the past.

Down here in the lowlands it was a very warm day…65-70 here in the Valleys ahead of the front…now it’s pouring, but it appears the back edge of the rain has now moved past Astoria where the rain has stopped.  The band of rain should gradually dissipate overnight.

Tuesday could be just spectacular by afternoon.  I have a funny feeling (not in my toe or anything along those lines) that we could get warmer than expected tomorrow.  We get a quick change to offshore flow the 2nd half of the day, but still enough cloud cover in the morning to prevent an inversion from forming.  And the surface high won’t have settle in eastside yet to give us strong easterly wind to limit warming.  Plus a very mild night in the 50s because of cloud cover too.  So a 10 degree rise puts us in the mid 60s.  65-70 is a definitely possiblity again.

Tomorrow night and Wednesday morning should be the strongest east wind we’ve seen yet this season.  A night of strong radiational cooling, inversion, and subsidence should give us at least 7 millibars easterly gradient through the Gorge.  WRF-GFS shows 40kt. easterly wind at about 2,000′ over the exit region of the Gorge.  That should give wind gusts over 50 mph in the usual windy spots in the Gorge and 60-70 mph at that favored Crown Point location.  Not too cold too…temps in the 50’s or 60 out there.  An early season Vista House visit Wednesday morning maybe???

Such a strong easterly wind plus the overnight cooling eastside (it’s November now!) probably means cooler in the eastside windy spots Wednesday compared to tomorrow.

Beyond that…the rainy/stormy action picks up again beginning this weekend.  Now I don’t think it’s just me, but when you look at the 00z, 12z, and 18z GFS doesn’t the 500mb pattern look like the winter of 2007-2008?  I mean the entire run…troughs that drop in on us from the northwest somewhat regularly.  Or maybe it’s just “wish-modeling”?

Chief Meteorologist Mark Nelsen