The National Weather Service has issued a weather warning for the Bay Area as dry, warm conditions give way to rain and thunderstorms beginning Thursday.
A weather system will move toward the coast Thursday afternoon, with the North Bay expected to see light rain by evening. Rainfall will become more widespread Friday, continuing intermittently throughout the day.
Thunderstorms are possible Thursday and Friday across the entire region, from the North Bay and San Francisco to the Peninsula, East Bay, South Bay and Santa Cruz County. The main uncertainty in the forecast is how severe the storms will be.
The weather service expects 0.25 to 0.75 inches of rain in valleys and up to 1.5 inches in coastal mountains. While the overall rainfall amounts pose no flood threat, slow-moving thunderstorm cells could produce heavy downpours that cause localized flooding, particularly in urban areas.
Bay Area roads may experience standing water and slippery conditions. US-101 and Interstate 880 warrant special attention as high-traffic routes where hydroplaning presents significant danger.
Temperatures will drop below normal levels. Rain should begin tapering off by Sunday, though forecast models disagree on conditions for next week.
