A brief but powerful storm is expected to hit the Bay Area this afternoon, prompting the National Weather Service to issue two separate flood warnings for the North Bay, which is expected to be hit the hardest.
The storm, which was expected to arrive by about 4 p.m., could drop as much as 4 inches of rain in some North Bay locations and bring wind gusts as strong as 55 mph in some coastal areas and at higher elevations, meteorologist Austin Cross said.
Because of the heavy rain, which could come down at a rate of one inch per hour, the weather service has issued a flash flood watch and urban and small stream advisory for Marin, Sonoma and Napa counties.
"The North Bay will get the brunt of the rain," Cross said, but, "The heaviest rains will only last a matter of hours."
The flood warnings both begin at 6 p.m. and are not expected to last past 4 a.m. Wednesday, when the most severe part of the storm will have moved out of the region, according to the weather service.
Southerly winds of 20 to 30 mph are expected tonight, with gusts of 45 to 55 mph possible on the coast and at elevations above 1,000 feet. The strongest winds are expected to subside by early Wednesday, weather officials said.
To help residents prevent flood damage, government agencies in the North Bay today provided free sandbags and sand.
A sandbag station is located in the city of Napa in the parking lot on the west side of Freeway Drive at First Street, city officials said.
There are also two stations set up in unincorporated Napa County, one at 3535 N. St. Helena Highway and another at 1501 Milton Road.
Petaluma city officials are also offering free sandbags. Residents can go to Hopper Street just west of Lakeville Street.
People in need of sandbags should bring their own shovels and gloves and be prepared to fill and transport the bags.