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January 2015

Mighty, Mighty Rain Shadow

Posted: January 5th, 2015


Mighty O?

Mighty O?


The warm front has passed and we’ve begun to dry out. Not that Seattle got that wet in the first place. While the region experienced one of its biggest events in a while, perhaps years, an incredible Olympic rain shadow centered right over Elliott Bay sheltered the City from rainfall amounts that would have otherwise caused widespread drainage impacts. (It should be noted that, despite a brief freak out when models disagreed on Saturday, the UW WRF-GFS nicely predicted the event on Friday.)


Preliminary “storm” totals across the City ranged from 0.46″ at Woodland Park to 0.31″ in SODO. Those amounts only generated 26 drainage calls from SPU customers over the past 48 hours. Also might as well reiterate that it was a warm front and we came within a degree of tying the high temperature record today.


Regionally, rainfall ranged from less than a quarter of an inch over Central Puget Sound to over a foot in the Southwest Olympic foothills near Lake Quinault. Sites around SPU’s Cascade Mountain reservoirs picked up 5-10 inches, prompting a flood warning to be issued for the Tolt River.


Save for the lack of snow in the mountains, the forecast is relaxing. No rain at all until at least Friday, according to this afternoon’s NWS update. A few systems will approach the region starting on Friday, but they do not look to be strong. (The latest ECMWF run keeps us rain-free all the way through next week, for what it’s worth.) Temperatures will remain above normal, climbing into the 50s each day, and by the time the threat of precipitation arrives this weekend snow levels will likely still be above 4000 feet.


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