Bay Area, Central Coast bracing for several days of heavy rain, strong winds, possible thunderstorms

The Bay Area and Central Coast are facing multiple rounds of powerful, atmospheric river-fed winter storms this week, bringing heavy rain, damaging winds, and a slight risk of severe thunderstorms, forecasters said Tuesday.

The National Weather Service said in its daily forecast discussion that light rain from Monday's system would continue across the North Bay on Tuesday, along with scattered showers for the rest of the region. 

Brief flooding in low-lying or poorly drained areas remained possible Tuesday. A flood watch remained in effect for the North Bay through Friday evening, expanding to include all of the Bay Area and Central Coast starting Tuesday morning. 

Heavier showers are expected to return late Tuesday night into Wednesday morning as two more storm systems move through. The heaviest rain is expected over the coastal mountains of the North Bay, Santa Cruz and Big Sur regions.  

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In addition, the first storm system is expected to drive fierce winds along the coast and higher elevations, with gusts up to 65 mph likely near the coast, and isolated gusts of 75 mph possible, the Weather Service said. Inland areas could see gusts between 25 and 55 mph. 

A high wind warning was issued for exposed coastal and mountainous zones, including the Coastal North Bay, the Marin Hills and western Sonoma County Hills, the Peninsula Coast, Southern Monterey Bay and Big Sur coast, and the interior Monterey County mountains. The warning was in effect from 4 p.m. Tuesday to 4 a.m. Wednesday. The Weather Service said damaging winds will blow down trees and power lines, and widespread outages were expected.

Meanwhile, the Weather Service also issued a wind advisory for other parts of the Bay Area and Central Coast, including San Francisco and the Bay shoreline, the North Bay interior valleys and mountains, the Santa Clara Valley and eastern hills. the Northern Monterey Bay and Santa Cruz Mountains, the Salinas and Carmel valleys, the Hollister area, and most of San Benito County. The advisory was also in effect from 4 p.m. Tuesday to 4 a.m. Wednesday, indicating winds of 25 to 35 mph with gusts up to 55 mph and higher along the ridgelines.

The Weather Service said that thunderstorms could also develop late Tuesday into early Wednesday. The service's Storm Prediction Center noted a low but increasing risk for severe thunderstorms capable of producing small tornadoes or waterspouts along the coast.

The second, potentially stronger storm system was forecast to arrive late Wednesday and persist through Friday, following a similar coastal track. Forecasters said this next system may bring more widespread moderate to heavy rainfall, with increased chances of flooding in urban areas and smaller rivers such as the Russian and Napa.

Wind gusts with the second storm may be slightly weaker than the first but still capable of causing additional power outages and tree damage. The risk of severe weather will also persist, though with a marginal risk of severe thunderstorms and a 2% chance of tornadoes or waterspouts along the entire California coast through Friday.

It's expected that the rain will taper off gradually Friday night into Saturday, bringing some relief before another potential series of storms arrives before New Year's Day.

Despite the threat of disruptions, meteorologists emphasized that the storms will help replenish regional reservoirs and snowpack. However, residents are urged to stay alert and have multiple ways to receive weather warnings over the next several days.

• Atmospheric River