Sunny, Chilly, and Very Dry!

November 19, 2013

The big weather story this evening should read “NON-STOP SUNSHINE AHEAD FOR 5+ DAYS!”.

But no, for weather geeks like me ,it’s more like this  “EXTREMELY LOW DEWPOINTS MEAN VERY COLD NIGHTTIME TEMPS WHILE STRONG GORGE WIND DEVELOPS TOWARDS THE WEEKEND”.

Skies are clearing this evening behind the morning cold front and temps are the coldest we’ve seen all day.

MarkTemp_SinceMidnightPDX_Bars_Hot_11pm

The well advertised dry air is coming in from Canada.  Models have been very emphatic shoving dewpoints down into the 30s, then 20s, then teens over the next 24 hours.  The airmass moving south out of Canada is the driest we’ve seen since sometime last winter.  It’s not exceptionally cold, just chilly.

But with such dry air, even daytime highs in the mid-upper 40s means low temps drop like a rock at night.  I expect widespread 20s tomorrow night as the wind calms down, and at some point between now and Sunday we should see some upper teens in the coldest outlying areas.  A similar pattern produced similar temps in November 2000.  Meteorological Pacific Northwest winter has arrived!

MarkColdTextPanel

Other than that, ridging is the big story through the short-term and long-term.  The 00z GFS had some sort of ridging over us through the entire 16 day run, with only one weak system squeezing through the ridge around Thanksgiving.  However, that IS the GFS.  The ECMWF turns a bit wetter and cooler sometime over the Thanksgiving Weekend, at least the 12z did.

With warming temps above 2,000′ late this weekend and over the weekend (50s at ski resorts), easterly wind through the Columbia River Gorge will turn very strong after Thursday, probably the strongest we’ve seen since 1 year ago when peak gusts were around 70-75 in Corbett and 85+ at the Vista House sensor.  Yes, that means some 100 mph gusts on the steps possibly over the weekend.  Nice timing…I’ll be keeping an eye on that.

Chief Meteorologist Mark Nelsen