The summer's first major heat wave could also produce a round of wildland fires.
UPDATED at NOON, SUNDAY, JUNE 28: The Red Flag Warning issued by weather forecasters for a broad swath of Southern Oregon and Northern California, remains in effect.
The only forecast zones served by JPR not included in the warning are Mount Shasta, Redding/Red Bluff, and the Northern California Coast.
The Red Flag Warning means three conditions are present, and a fourth could be: high heat, high wind, and low humidity. And lightning could strike, as thunderstorms move into the area.
These are prime conditions for fires to start and spread rapidly.
The National Weather Service rated the chance of thunderstorms no higher than 30% through the weekend, but any storms are unlikely to carry much--if any--precipitation.
The heat wave is expected to last through at least the July 4th holiday weekend.
