A cold, low pressure system from the north will move through southern California by Tuesday. This system is expected to bring showers and a slight chance of thunderstorms. The snow level will rise to around 4500 feet tonight and around 5000 feet on Sunday, then fall to around 4000 to 4500 feet for Sunday night and Monday. Chances of receiving one inch or more of rainfall/liquid-equivalent for the weekend are generally 80 to 90 percent from the coast to the mountains with, an 80 percent or greater chance for two inches or more of rainfall/liquid-equivalent for the typically wetter mountain locations.