Evening Earthquake, East Wind, & The Next 10 Days

December 13, 2017

10pm Wednesday

Did you feel the quake last night?  The largest earthquake in our area in the past 2 years hit just a mile or so east of Scotts Mills.  That’s near Silverton.

A 4.0 sure doesn’t generally cause damage, except we did get one photo of a Christmas ornament fallen off a tree, and a tree fell off a bookshelf.  For some of us it was the first quake we’ve felt since that Spring Break Quake in March 1993.  This quake was centered within a mile of that one!  Check out all the 4.0 or larger quakes (over land) in our area since 1990

Let’s talk weather…

The easterly wind has spread back across more of the metro area this evening and gusts within the Gorge increased a bit too after a lull yesterday afternoon/evening.  Check out the past 9 days…ridiculous and the longest/windiest period we’ve seen since January 2009.

The very good news is that the airmass coming in with Friday’s cold front is MUCH colder overhead which will kill the inversion and kill the high pressure in Eastern OR/WA.  In fact by Friday afternoon I expect a breezy WEST wind through the other end of the Gorge.  Yes, Friday afternoon it should be calm at Vista House for the first time in 11 days!

The upper-level ridge over us will weaken a bit over the weekend, then strengthen again, but a bit farther west as we go through the next 7-10 days.  You can see the change from tonight’s 500mb map…

to 10 days out…Saturday of Christmas Weekend

During this time one or two cool systems will drop in over us from the north or northwest.  First will be Tuesday/Wednesday and possibly a 2nd late next week.   Neither will be all that wet, but bring showers and some mountain snow.  This setup will likely turn us a bit cooler as we head toward/into Christmas Weekend.  But models are in disagreement on exact placement of the ridge.  If it’s close to us we’ll just have sunshine and easterly wind again.  If it sets up farther offshore we’ll be significantly colder (arctic air) and that brings up the possibility of snow.  I’m leaning toward the first option for now.  It’s still a mainly dry pattern as I pointed out on my 12 Day Trend graphic this evening:

This is bad for ski resorts; we need new snow, and no significant snow is in sight for the next 6 days.  Christmas Break skiing/snowboarding will be limited, at least to start.  Hopefully that midweek system will produce at least a foot of snow.  We’ll see.

Chief Meteorologist Mark Nelsen