The National Weather Service is forecasting thunderstorms for the Sierra starting Tuesday through Thursday.
Meteorologists say a low-pressure area off the coast will bring mountain thunderstorm activity each afternoon and evening this week.
The greatest threat will take place over the next few days. Heavy rain is in the forecast -- particularly for the east side of the mountain crest.
There's a chance of some rain in the Valley toward the Redding and Red Bluff areas Wednesday.