Overview
- Southern California faces the most volatile conditions Monday as a squall line brings rainfall rates near or above one inch per hour, a slight tornado risk, and gusts that could top 60 mph.
- Evacuation warnings are in effect for Los Angeles burn‑scar zones, and a flood watch covers Los Angeles, Ventura and Santa Barbara counties during the peak downpours.
- Sierra travel is deteriorating quickly with chain controls in place, ridgetop gusts potentially exceeding 100 mph, and 3 to 5 feet of snow forecast above 7,000 feet by Wednesday, with worst‑case totals higher in the southern Sierra.
- Two main waves are expected: heavy rain and thunderstorms Monday into early Tuesday, then a colder system late Tuesday into Wednesday that drops snow levels to roughly 3,000–4,500 feet and threatens the I‑5 Grapevine.
- The Bay Area saw up to 5.5 inches in coastal highlands on Sunday and faces another 0.5–1 inch Monday with 25–40 mph gusts, while widespread winds of 50–70 mph are forecast on Southern California mountain slopes Tuesday night into Wednesday.