Officials upgraded a heat advisory for the region to a red flag warning for most of the state.
Forecasters say the hot weather across Oregon and Southern Washington created a large region of low pressure, making for unstable wind conditions which could cause rapid growth in existing wildfires.
An upper-level system moving north from California is expected to bring thunderstorms into the region through Tuesday, weather service officials said.
The Oregon Department of Forestry is standing by to help put out fires, as lightning strikes are expected to spark new wildfires across the dry Oregon landscape.
Fire officials ask people to immediately report smoke from lightning strikes to 9-1-1.