Wet, windy storm moves into San Francisco Bay Area; up to 10 inches expected over weekend

Rain pelted parts of the San Francisco Bay Area and gusty winds swept in Friday from a storm that's expected to unleash up to 10 inches of rain through the weekend in parts of the drought-stricken region.

North of San Francisco, businesses in Marin, Napa, Solano, and Sonoma counties stacked sandbags to prepare for possible flash flooding from swollen waterways as rain started falling in the North Bay. Winds of up to 15 mph were recorded east of the city Friday morning, and the blustery weather could knock down trees and power lines, causing isolated power outages, the National Weather Service said.

The rainfall won't make a significant dent in the state's historic drought, but it's a welcome change after six dry weeks in the area. For the first time in recorded history, there was no measurable rainfall in downtown San Francisco in January, when winter rains usually come.

It would take 150 percent of the average rainfall for California to recover from the dry period, state water resource officials say. But snow is more important than rain because snowpack supplies about a third of the water needed by residents, agriculture and industry.

The Weather Service issued a heavy rain, high wind gust, and flash flood warning for the Bay Area through Monday. The storm is expected to start slowly, push south Friday afternoon and drop rain throughout the region through Sunday.

The heaviest downpours are forecast in the North Bay, where up to 7 inches of rain is expected to overwhelm waterways and roadway drainage systems, leading to flash flooding.

Urban areas could see up to 4 inches of rain, while Marin and Sonoma counties could see 10 inches of rain through Sunday, Weather Service lead forecaster Roger Gass said.

Additionally, wind gusts across the Bay Area over the next few days could hit 20 to 40 mph, with potential gusts up to 60 mph. But it won't be cold, with temperatures in the upper 50s to low 60s.

Since Dec. 20, rain has been nearly nonexistent across much of California and Nevada, halting hopes for drought improvement.

Plus, California's second snow survey this winter found the Sierra Nevada snowpack is far below normal after a dry, unusually warm January. A higher snowpack translates to more water for California reservoirs to meet demand in summer and fall.

Water resources managers said heavy rain and cooler temperatures in the next three months would be required for the snowpack to build and give Californians hope for beginning to recover from the drought this year.