A cold low-pressure system is forecast to swing across Southern California Friday night, bringing a change of rain to San Diego and snow to local mountains, according to the National Weather Service. A winter weather advisory is in effect from 5 p.m. Friday to noon Saturday for San Diego County mountains, according to the NWS. The system will bring light rain, gusty winds and cold temperatures. The snow level is expected to fall rapidly through Friday evening, with areas of westerly winds 25 to 35 mph and gusts to around 55 mph.