The following is a post from the National Weather Service, Eureka Office from their Facebook page:
Heavy showers are expected from Friday through Saturday morning. Rainfall total amounts for Mendocino County will range from 3.5 to 6 inches, with higher amounts in localized areas. Rivers will rise rapidly in response. Russian River near Hopland is expected to reach 15 feet for flood stage on Saturday. At 15 feet flooding of Highway 175 is expected at the approaches to the Russian River bridge. Expect minor flooding of cropland on the west bank of the river. A Flood Watch is in place for Russian River near Hopland from late Friday night to Saturday afternoon.
Navarro River near Navarro is forecast to rise on Friday to 16 feet and peak up to near 20 feet on Saturday evening. Flooding stage for the Navarro River is 23 feet. At this moment it is not expected to reach flooding stage. Otherwise, we will continue to monitor the stage in case flooding is expected.