Petaluma and Penngrove are two of the places the National Weather Service says are vulnerable.
The warning is in effect until 5:15 p.m. Wednesday.
LIVE RADAR: Track storms as they move through the Bay Area with Live Doppler 7
Sebastopol, Forestville, and Graton are under a Flash Flood Warning until 5:45 p.m., partly because Green Valley Creek is overflowing its banks.
Residents are advised to move to higher ground and avoid walking or driving through flood waters.
RELATED: Storm triggering early problems on North Bay roadways
Flash Flood Warning including Petaluma CA, Penngrove CA until 5:15 PM PST pic.twitter.com/ddisXsGIkA— NWS Bay Area (@NWSBayArea) January 16, 2019
Flash Flood Warning including Sebastopol CA, Forestville CA, Graton CA until 5:45 PM PST pic.twitter.com/WM1kw3coT3— NWS Bay Area (@NWSBayArea) January 16, 2019
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