A Pacific storm spread needed rain to much of California on Friday, causing traffic snarls but no immediate trouble for communities near slopes left barren by wildfires. Northern and central sections of the state felt the brunt of the storm’s impacts but the threat of heavy rain rapidly diminished as it spread into Los Angeles and flash flood watches in local mountains were canceled. Rainfall rates were highly variable from the coast to the Sierra Nevada, but all of it was needed in a state that has seen only modest improvement in its drought situation.