The second front of a drenching three-bout storm made landfall Thursday and was expected to saturate the North Coast with 3 to 6 inches of rain overnight and through Friday.
In advance of the soaking, the National Weather Service issued a flash flood watch for a large portion of Northern California, including the North Coast, saying small stream and creek flooding is possible Friday, and urban flooding likely in Petaluma and elsewhere with the arrival of a fresh storm.
More rain is expected to start Saturday. That third storm front could push the upper Russian River as much as 3 feet over flood stage in one spot of Mendocino County — Hopland — by Sunday afternoon, according to projections by the California-Nevada River Forecast Center. In Sonoma County, the lower river was not predicted to flood, but it could reach about 3 feet below flood stage by Monday.
Like the respite in rainfall late Wednesday and early Thursday, a pause in rain was predicted for tonight. But with the ground already saturated and runoff building, trouble was expected.
“We're very concerned actually,” Petaluma Fire Chief Phil Sutsos said Thursday, shortly after arranging for the city community center to be put to use as an emergency shelter, if needed.
An even wetter storm was forecast for Saturday night, with total rainfall by Sunday exceeding a foot in the wettest locations — places like Cazadero, Venado and other coastal hill locations that typically see the heaviest rainfall, National Weather Service Meteorologist Diana Henderson said.
The weather service stopped short of issuing a flash flood warning, which would suggest a more immediate and likely breach of creek banks.