Veterans Weekend Sunshine & Strong Gorge Wind Ahead

November 8, 2018

7pm Thursday…

Today was another nice early November day; fog to sunshine and comfortable temps.  Much of the metro area did see frosty conditions early.  The 37 at PDX was the coldest so far this season, but many areas dropped into the upper 20s

PDX Observed Low Today

Tonight should be similar under mainly clear skies.  The light offshore (easterly) wind flow overhead did push our afternoon temperatures into the comfortable mid 50s.  I doubt we get frost at PDX tonight, nothing unusual since the average first frost is November 15th at that location.  Each year is different with a first frost here in the city typically ranging from late October to sometime in December!

Mark First Frost Last Few Years

Today is our 3rd dry day; looks like we’ll make it to 7 or 8 days before showers return later Tuesday or Wednesday.

2017 Rainfall at PDX Last 10 Days

After a weak weather system drops by tomorrow evening and Saturday morning, a strong area of cool high pressure settles in east of the Cascades for a while at the surface.  By Saturday afternoon we’re into easterly flow which clears out skies nicely.  The result is a mainly sunny 3 day weekend!  Pretty tough to do in November.  Check out the surface map for Sunday morning at 7am:

wrf_7amSunday

Then Monday at 7am:

wrf_7amMonday

That’s a typical cold-season east wind event for our area; 6 millibars easterly flow through the Gorge Sunday ramps up to 9 millibars Monday.  We’ll be in an inversion with that cool air flowing in from Eastern OR/WA near sea level.  Up above, 850mb temps reach over +10 C.  That much gradient squished down low under the inversion will easily give us gusts 55-70 mph in the western Gorge and 75-85 mph up at Crown Point for the first time this season.  Have you been missing the wind since February?  Well, the Monday holiday should deliver perfect conditions to reconnect your nostrils/eyeballs with that stinging cold wind.

In this setup the east wind won’t make it very far into the metro area, mainly just east of I-5/I-205.  But it’ll be enough to keep fog away Sunday-Tuesday.  Easterly flow dies down later Tuesday through the end of next week as another weak system (like tomorrow’s) tries to crash the ridge party.  That won’t give us much rain or mountain snow.

To sum up the next week:  Mainly dry with lots of Gorge wind Sunday through early Tuesday.  No signficant mountain snow for at least another week either.  The 10 day snow forecast for our area from both the ECMWF/GFS models show less than a foot up there in the next 10 days

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Now beyond the 10 day period there are HINTS that we might see a change.  The ECMWF 46 day run last night shows a bit cooler/wetter conditions for Thanksgiving Week.  That’s because ridging seems to want to develop much farther offshore.  I noticed the GEM model keeps the ridging overhead though.  The result is low confidence right now beyond NEXT weekend.

500za_week2_bg_NA

Just for kicks, here’s the week 3 forecast

500za_week3_bg_NA

Interesting and definitely cool.  But not a wet pattern.  By the way, about two years ago I stopped showing these charts beyond the 2nd week.  That’s after a great talk by Cliff Mass, pointing out how poorly the weekly forecasts had been doing.  Beyond week #2 the accuracy definitely takes a nosedive!

Enjoy the sunshine this weekend, and don’t bother raking your leaves if you live near/in the western Gorge.  The wind should blow them westward and out of your yard by early next week.

Chief Meteorologist Mark Nelsen