At least that part of California. It's a gigantic state and some areas see fairly significant seasonal rain. This storm, however, will impact a region that includes the Mojave Desert - the dryest place in North America.
IIRC, The excellent book Dreamt Land says 2/3 of California's precipitation falls in the northern 1/3 of the state. But it's the southern part with the ideal climate for agriculture. Hence the largest water movement system in history.