A Change in Sight

December 7, 2006

I suppose a change will be nice for those exposed to the strong Columbia Gorge outflow this evening.  Troutdale Airport gusted to 41 mph earlier and Corbett School had a gust to at least 68 mph again this evening.  That makes for about 48 hours of gusts over 50 mph now.  Even after all these years of living on the east side of the metro area (since 1991), I still find it amazing that the wind can gust to 70 mph at the west end of the Gorge yet be calm only 15 air miles to the west.  All that fast-moving air fans out across the metro area.  And I had a gust to 16 mph at my home while it was gusting up around 70 just a mile & a half away.  I get blocked by hills about 1,500′ just to my northeast and only get gusty easterly wind when it comes down off the Cascades too.  Gradient from PDX-DLS peaked at around 9 millibars earlier today, dropped to around 7 early afternoon, and is now back to 8.5 or so.  It should peak again sometime tomorrow, then drop off dramatically tomorrow night as this east wind episode ends.  Someone earlier on the comments asked if there was any damage with these windspeeds.  Generally since 65-70 mph gusts occur at times during the winter, it takes gusts higher than that to cause lots of trouble. I think it has to get up around 80-90 mph or so to bring down lots of trees or damage roofs.  That hasn’t happened at the west end of the Gorge since the cold spell just before the Feb. 1996 flood.  I know several anemometers recorded 90-100 mph gusts then.

Now, on to the rainy season resumption.  Weak system tomorrow night and another Sunday still get torn apart a bit by the split offshore.   Then much more active fronts Monday through the rest of next week as strong westerly flow of one sort or another resumes.  It’s going to get wet again!

As for cold or snow? I too noticed the 00z GFS yesterday had significant cold air dropping in with a trough about next Friday-Saturday (15th-17th timeframe), not really an arctic blast but cold and showery behind Thursday’s front.  New 00z GFS and 00z Canadian just out show a chilly 1000′ snow level or a bit less, but definitely no arctic air and just a brief cooldown before more rain follows.  How surprising that the GFS would back off on cold air!!!  Of course I meant that sarcastically…enjoy one last dry day tomorrow and head up to Crown Pt. in the morning (or afternoon) if you want to feel some wind…Mark