A Hazy Day Today & Seattle TV Weather Change

October 10, 2012

I was really surprised how hazy it was on the drive in to work today, especially considering we don’t have any widespread fire smoke around the Pacific Northwest.  I checked the Air Quality Index from Oregon DEQ and discovered that sure enough we were solidly in the MODERATE category yesterday and today.

I’m sure there is some fire smoke left in the air, but we are now entering the inversion season.  From now through February it’ll be common for cooler air to get stuck in the lower elevations due to the low sun angle not being able to heat the ground very effectively.  For example the high in Portland today was 66, but at Horse Creek RAWS at 3400′ SE of Molalla it hit 67.  If that warmer air mixed down, we would have been well into the 70s or even 80.  Once the temperature is the same or cooler at lower elevations, there is little to no mixing of air in the valleys up into the rest of the atmosphere; basically we’re breathing our own pollutants.

This will all change Friday of course as a cold front moves overhead.  That first wet system is real weak, so maybe just a quarter inch of rain.  The 2nd system stays a little farther north on Saturday, so we stay mostly dry here in NW Oregon.

I’m still keeping a close eye on a moist westerly jet for later Sunday and Monday.  Models have been waffling on rainfall intensity and track of a deep (or not deep) area of low pressure.    Last night’s 00z GFS was real stormy looking.  The 12z ECWMF had a deep low farther north, and the 12z GFS had a much weaker storm.

I’m confident we have a good soaking coming though.

In TV weather news…

Do you remember Rebecca Stevenson, the Chief Meteorologist of KIRO-TV we interviewed on the NW Weather Podcast last spring? 

She is no longer with KIRO-TV.

I don’t know any details other than it couldn’t have been a happy departure since all evidence of her is gone from the KIRO website.  That’s not too shocking; standard procedure in this business.  I do know she did a great job and was a genuinely friendly person off-air.  Plus she knew her meteorology and looked great too!

If you’re from that area and want to give her a few kind words, her Facebook page is here: http://www.facebook.com/#!/pages/Rebecca-Stevenson/165871293451331

Ha, I see there is even a  GET REBECCA STEVENSON BACK ON TV  Facebook page by her loyal fans.

Chief Meteorologist Mark Nelsen