Many county offices of emergency services from Del Norte to Placer are urging people to prepare for rising rivers and streams. That may occur if six to eight inches of rain fall over the next four days as expected.
John McEldowney with the Placer County Office of Emergency Services says flooding along the county's creek systems is common. But, he worries this type of storm could hit some areas with a lot of rain in a short time.
"It's a very large storm. It's going to hit most of northern California. But if it were to stall out or if it veers a little farther south, we'll get more rain than that. A lot of northern California farther north than us is looking at eight-to-ten inches of rain."
Brad Alexander is with the California Governor's Office of Emergency Services. He says Humboldt, Mendocino and Santa Cruz counties may have high winds and flooding similar to what they had during storms in December.
"We are coordinating with coastal counties and inland counties. Our coastal regional is currently active on a monitoring status and supporting any of those last-minute requests for sand-baggers or mutual-aid requests from surrounding counties."
The National Weather Service has issued a flash flood watch for the Pacific coast from San Francisco to southern Oregon.