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January 2015

Eroding Ridge

Posted: January 12th, 2015


The ridge of high pressure that has more or less been stuck over the west coast will continue to erode away this week. That will enable a few more frontal systems to make their way inland this week, and perhaps next week. With respect to our nearly bare mountains, hopefully they will arrive and hopefully they’ll be cold.


Before the next rainy system arrives on Thursday, we’ll have to endure three more photogenic, foggy, and slightly warmer than normal mornings. But the latest NWS forecast only shows just over a half of an inch falling across Seattle late Thursday/early Friday, followed by another quarter of an inch over the weekend. The system actually is the northerly fringe of a narrow atmospheric river, and the latest UW WRF-GFS has closer to an inch in the City on both Friday and Sunday, so the forecast bears some close monitoring.


In the Cascades, the latest NWS forecast calls for 1-2″of precipitation on Thu/Fri. Snow levels at the same time climb over 5000′ and then gradually drop toward 3000′ by Sunday. Again, signs of atmospheric progression and cooling are welcome, though there appears to be little agreement among models in the long term.


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