Southern California is facing flooding rain, isolated severe thunderstorms and low-elevation snow to end the weekend, which is common in a strong El Niño weather pattern. A storm will strengthen as it moves over Southern California and sweep across the interior Southwest into Sunday night. "While a blockbuster storm is not likely, enough rain will fall to cause minor flash and urban flooding issues and trigger a few mudslides in recent burn areas," AccuWeather Senior Meteorologist Alex Sosnowski said.