* WHAT...Southwest winds 20 to 30 mph with gusts up to 60 mph expected. Wind gusts in the mountains up to 75 mph. * WHERE...Nespelem, Okanogan, Cashmere, Tonasket, Entiat, Leavenworth, Number 2 Canyon, Wenatchee, Omak, Number 1 Canyon, Chelan, Disautel Pass, Brewster, Plain, Oroville, Bridgeport, and Pangborn Airport. * WHEN...From 8 PM Wednesday to 11 AM PDT Thursday. * IMPACTS...Damaging winds will blow down trees and power lines. Widespread power outages are expected. Travel will be difficult, especially for high profile vehicles. * ADDITIONAL DETAILS...Strongest wind gusts for the Okanogan Valley are expected south of Omak. Gusts 40 to 50 mph expected between Omak and Oroville.