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January 2015


Posted: January 8th, 2015



Not much activity to discuss at the moment. A somewhat persistent ridge of high pressure is, if not outright blocking, then significantly weakening low pressure systems as they approach the region. Said regime is, of course, providing us with this fog and a little bit of, uh, olfactic dissonance.


SPU participated in an investigation yesterday to determine the source of particularly pungent perfumes reported regionally. Given that we provide drainage and waste water services for Seattle, and that complaints seemed more densely clustered around the NW corner of the City, questions arrived early. But thanks in part to last weekend’s rain shadow, and in part to the diligence of SPU (and King County) crews and monitoring staff, it was quickly determined that the source was not local sewage.


KOMO meteorologist Scott Sistek was on the case from the start and has a detailed analysis on his Weather Blog. UW’s Cliff Mass followed last evening, favoring the hypothesis that inversion-trapped vapors from recently flooded Snoqualmie valley pastures were gently transported westward. (Typically after floods westerly mixing is strong; this week’s post-warm-frontal regime is a bit odd for January.)


While the airborne idea does seem “reasonable,” let’s not rule out waterborne hypotheses. A notably low -1′ MLLW tide occurred late on Tuesday night. Inland odor reports seem to be sparse. Estuaries often smell. Perhaps after this weekend’s heavy rain, highly turbid freshets, which likely made their way down through the Ship Canal, Duwamish Waterway and other Sound deltas on Tuesday, adversely added to the perihelion influenced, larger than normal mud flat mixes?


Enough though, right? As Puget Sound Clean Air Agency meteorologist, Erik Saganić insinuated on KING, maybe it’s just the smell of all of the above and then some simply made worse by this relatively warm, foggy weather. We probably won’t get many more chances to figure it out, and we probably won’t need to either.



Fogginess will stick around through tomorrow before a dying cold front passes through early on Saturday. A few sprinkles are possible but it’ll mostly just thicken the gray. Later on Sunday a stronger system will approach the region, but it’s expected to more affect Oregon and leave us with only slightly more organized sprinkles again. Early next week looks to be warm, dry and hopefully unfragrant.


NWS Area Forecast Discussion
NWS Forecast Table Interface—Seattle
NWS Forecast Table Interface—Tolt Reservoir
NWS Forecast Table Interface—Chester Morse Lake
SPU Water Supply Outlook