Sunday, January 18, 2015

A Moderate Blow

 Announcement

The Northwest Weather Workshop is the major local meeting to discuss the meteorology of the Pacific Northwest.  If you would like to give a talk during this year's gathering (Seattle NOAA facility, February 27-28), please send me an abstract during the next few days.  More information is found here:
http://www.atmos.washington.edu/pnww/

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There was a well forecast minor windstorm last night associated with a Pacific cyclone that crossed Vancouver Island during the morning hours. Here is a infrared satellite image around 1 AM Sunday...you can see the swirl of clouds associated with the storm offshore.


The maximum winds during the 24h ending 8 AM tells the story.  A number of locations in Puget Sound hit 40 mph, and winds exceeding 50 mph were found on the coast and over portions of NW Washington.  At least 50,000 customers have lost power in the City Light and Puget Sound Energy networks.


The UW WRF model forecasts starting at 4 PM yesterday captured the event well.  Here is the 6-h forecast for 10 PM Saturday... a 989 hPa low offshore with large pressure differences to its south (the solid lines are isobars, lines of constant pressure)

 By 4 AM, the low had moved to Vancouver Island and there was a large pressure gradient (and winds) over western WA.  Wind are still strong at 8 AM, but will decline during the day (although it will still be breezy during the game).
 Yesterday, the storm tapped warm, tropical air, producing a lot of rain.  And there were amazing temperature contrasts across the state.  It hit 60F in Seattle (unnerving to the arctic-dwelling Green Bay Packers) but only in the 30s in eastern Washington, where cold air is trapped in the Columbia Basin bowl.   This cool air was a godsend for Stevens Pass---the cold air moved westward in the pass (pulled by the approaching low) and helped to maintain snow, while higher elevation locations (e.g., Paradise on Mt. Rainier) turned to rain.   They got 16 inches there before it turned to rain.  Good snow over NE Washington as well, such as in Mazama.



1 comment:

email Mr. Reinholtz said...

The Mt Baker weather station clocked a max blow of 100 mph at 3am. Not sure how accurate it is but it seemed to build up to that point which was consistent to what happened in Bellingham