Overview
- Monsoonal moisture is expected to begin Saturday night into Sunday and persist into early next week, shifting storm chances across the state.
- Lightning probabilities are modest but nonzero, about 10% in the Bay Area, 10–20% in coastal mountain counties, and 20–25% in parts of the Sierra Nevada.
- A red flag warning in northeastern California for Friday reflects near‑term elevated fire danger from gusty winds and low humidity ahead of the monsoon arrival.
- Forecasters say Sierra mountain storms Monday–Tuesday may produce roughly a tenth of an inch of wetting rain that could lower local fire risk while deserts and lowlands remain exposed to dry lightning, strong outflow winds, and flash flooding.
- Dry lightning has triggered major fire outbreaks in the past, so emergency managers are monitoring the event closely because isolated strikes into dry fuels can rapidly start fires and strain response resources.