Dry Outlook

October 20, 2008

Snapshot  The big story as I return from some vacation time this evening is the dry and mild looking weather maps over the next 7+ days.  Hard to find much of any rainfall as we head towards the end of October.  Yet this is the time of year that rainfall really starts to pickup.  The last week of October and 1st week of November generally sees a tremendous increase in rainfall most years as we plunge quickly in the rainy season.  November is only slightly drier than December, making it the 2nd wettest month of the year here in Portland.  But basically November, December, and January are the 3 "big" months for rainfall.  By February the heavy rains of late Fall through early winter are fading a bit, interspersed with a few dry spells, making it somewhat drier than the other 3 months.

Not this year though…some sort of upper level ridging should sit near the West Coast over the next week or so.  This will add to the very nice (boring for the wx geeks) Fall we've had so far.  I didn't do too much last week on my time off, but there was plenty of sunshine for hikes yard/garden work.  Couldn't ask for much more in mid October!

Surface high pressure develops overhead tonight and tomorrow, then shifts east of the Cascades quickly late tomorrow afternoon.  The easterly gradient across the Cascades (and through the Gorge) builds up dramatically by late evening.  We're into that time of year where an easterly wind can begin anytime of the day, not just in the late night and early morning hours.  So I think the wind will blow all night tomorrow night east of I-205 within a few miles of the Columbia River.  WRF-GFS peaks out around 8 millibars by Wednesday morning PDX-DLS.  That should give us the first 50-55 mph gusts of the season at the west end of the Gorge.  That'll take a few more leaves off the trees out there.  You'll gain a few leaves in you live in Beaverton!  Mark Nelsen