If the 24-hour forecast is for two (2) inches of rain or more, and the other antecedent conditions are met, flooding may occur sometime in the next 24 hours.
If you live in a flood prone area, you should have a personal evacuation plan and keep an eye on the weather and the antecedent conditions. Monitor weather agency broadcast warnings via television and radio. Your personal evacuation plan should be implemented if you sense flooding may occur.
Contra Costa County is susceptible to flash flooding.