A storm that delivered a body blow to Northern California, endangering homes and leaving 40,000 customers without electricity, rolled through the Central Coast Friday toward Los Angeles. The weather system dumped fractions of an inch of rain in San Luis Obispo County but Rocky Butte, a summit near San Simeon, received nearly 5 inches over 24 hours. Rain was expected to continue shifting slowly southward before the system finally tapers off late Saturday.