The National Weather Service upgraded its fire weather watch to a red flag warning Tuesday as a cold front approached central Oregon and was expected to move to the northwest across the Mid-Columbia.
The cold front will bring a chance of thunderstorms and gusty winds, according to the weather service forecast.
In the Tri-Cities a 50 percent chance of scattered thunderstorms is forecast for overnight Tuesday, mostly before 11 p.m. Winds could gust as high as 29 mph through the night.
There could be some small hail in parts of the Mid-Columbia, according to the weather service.
Lightning already has started fires in the region this week.
Monday morning a storm moved quickly over Benton County and lightning strikes may have set two small wildland fires south of Kennewick, according to Benton County Fire District 2.
One was on the ridge west of Interstate 82 south of Locust Grove. The second was at Interstate 82 and Dallas Road.
The U.S. Forest Service reported responding to 11 smoke reports in Chelan, Kittitas and Yakima counties from more than 520 lightning strikes recorded since noon Monday in Central Washington.
Lightning also is being blamed for fires spotted Monday in the Umatilla National Forest. The largest were four or five acres.
In Idaho a lightning-sparked fire that started Monday was burning on the Department of Energy’s Idaho National Laboratory’s 890-square-mile site Tuesday,
The Sheep Fire had grown to 85,000 acres by early afternoon Tuesday.
Non-essential employees were being evacuated at key lab facilities Tuesday.