A fresh dousing of much-needed rain is expected to begin falling Sunday night across the Bay Area, offering the region its most meaningful helping of moisture this year after a record run of dry weather.

A storm system dipping down from the Gulf of Alaska slowed slightly over the weekend as it approached the coast, promising .25 inches of rain in San Jose and .4 inches for the East Bay from late Sunday night through Monday, according to Brayden Murdock, a National Weather Service meteorologist.

The coastal mountains and the Central Coast are expected to receive much more precipitation, with 2.5 inches of rain expected to fall over the Santa Cruz Mountains and up to 4 inches over the Big Sur coast. Meanwhile, up to a foot of snow could fall over the Sierra Nevada — particularly the highest peaks south of Highway 50.

The rain and snow are a welcome reprieve after the driest January and February in the Bay Area’s recorded history. But Murdock cautioned that much more rain is needed to alleviate drought conditions across Northern California.

Rainfall totals since Jan. 1 have been downright paltry compared with previous years. On average, San Jose usually receives 7.28 inches of rain by this time of the year. San Francisco normally gets 11.49 inches of precipitation and Oakland usually gets 9.24 inches of rain by now. But those cities have yet to crack an inch of precipitation since the New Year, Murdock said. San Jose has received .11 inches of rain, San Francisco has received. 95 inches and Oakland has recorded. 51 inches.

As the storm approached, almost the entire state remained mired in severe drought, and about a third of it experienced extreme drought, according to the U.S. Drought Monitor.

“This is a step forward after taking five steps back,” Murdock said. “It does help, but we would need a few more of these to really gain some ground over what we’ve been missing over the last few years.”

Strong, gusty winds are expected to precede the upcoming rain, with gusts reaching 45 mph across parts of the East Bay foothills, as well as the Santa Cruz and Big Sur mountains, Murdock said.

Of growing concern are the possibility of debris flows through burn scars along the Big Sur coast. The National Weather Service issued a flash flood watch through 6 p.m. Monday for the Big Sur coast, including the Colorado and Dolan fire burn scars.

To the east, a winter weather advisory was issued for much of the Sierra south of Interstate 80. Donner Pass could receive 2-6 inches of snow, though heavier amounts are expected south of Highway 50, Eric Kurth, another National Weather Service meteorologist, said.

Any snowfall is direly needed for the Sierra, were snowpack sat at 46% of average for this time of year, according to the California Department of Water Resources. That’s because hardly any snow fell since the New Year, after a record-breaking dumping of snow in December.

“Any contribution is good,” Kurth said. “But this isn’t really a super wet storm, so it’s not going to make a huge difference.”

Source: www.mercurynews.com