The National Weather Service has issued a red flag warning that's in effect until 11 p.m. Saturday.
Forecasters say Saturday night's thunderstorms will come with abundant lightning.
Some of the thunderstorms could produce erratic winds with gusts to 40 mph as well as pea- to marble-size hail.
The storms are moving northeast at 20 mph over the Lower Columbia Basin, including the Tri-Cities, Prosser and Connell, the weather service reported at 8:30 p.m. Scattered storms will move across Franklin County through 10 p.m. The storms will contain small hail and brief heavy rain.
The frequent lightning and critically dry fuels may result in numerous fire starts, the weather service said.
A red flag warning means that critical fire weather conditions are either occurring now or will shortly. A combination of strong winds, low relative humidity and nd warm temperatures can contribute to extreme fire behavior.