This has been a very windy period over portions of eastern Washington due to a large pressure difference across the Cascades (higher pressure to the west, lower pressure to the east).
The maximum winds today since midnight (see below) reached 51 mph near Ellensburg. Winds were mainly strong near and downstream of Ellensburg and east of the eastern terminus of the Columbia River gorge.
The winds exiting these Cascade gaps strengthen during the evening after the daytime heating in eastern Washington causes the pressure to fall there (and thus increasing the pressure difference across the Cascades0. To illustrate, below are the winds forecast for this evening (in mph)...a lot more greens in eastern Washington, which means stronger winds.