April 27, 2019

Strong Winds Descend into Eastern Washington

A frequent springtime weather feature of eastern Washington is the tendency to get strong northeasterly winds--sometimes with blowing dust.

And such strong winds are occurring right now.    Here are the maximum gusts since midnight (click to expand).  Several locations, from near Wenatchee to Yakima, are gusting to near 50 mph from the northeast.  Strong winds in the Strait of Juan de Fuca as well.

A close up gives you a better view....59 mph just just of Lake Chelan and 61 mph near Blewett Pass...with strong winds extending out into the Columbia Basin. 50 mph at some high elevation locations, such as near Snoqualmie Pass and 80 mph at White Pass.

 The reason for all this?  The passage of an upper level trough from the Northwest, resulting a a very large pressure gradient that is consistent with northwesterly winds in the lower atmosphere.  Here is the forecast weather map at 850 hPa (about 5000 ft) showing heights and winds at that level.  Strong northwesterly winds aloft!

And when those winds interact with the Cascades they are strengthened over  the eastern slopes--something called mountain wave amplification.  To illustrate, here is the wind gust forecast of the UW WRF model for 11 AM this morning.   The blue colors are 45 kt or more....the model was certainly going for the strong winds.

Northwesterly winds are also producing a very active Puget Sound Convergence zone, as air moving off the Pacific is deflected around the Olympics and converges over the Sound.

The National Weather Service had wind warnings out for this event  even yesterday (see below)

and among the issues they warned about was raising dust...which has occurred in some locations (like a location just east of Spokane)--see below.

Things should quiet down tomorrow.... and a sunny, dry day beckons..

1 comment:

  1. FYI, we had a bit of a gust here on the west side of the Cascades. At the time the crane fell at Fairview and Mercer, my anemometer, a mile north and a bit east of there, read a gust of 24 mph.


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