Cold, wet weather and mountain snow could be possible when a storm from the Gulf of Alaska reaches San Diego County Wednesday afternoon, according to the National Weather Service.
The cold Pacific storm was expected move inland across Southern California and to stick around San Diego County through Friday morning, forecasters said.
"A cold low pressure system dropping southward down the California coast will bring an abrupt change in the weather pattern over Southern California by mid-week,'' according to a NWS advisory.
Daytime temperatures were expected to fall to as much as 10 to 20 degrees lower than seasonal averages Thursday afternoon.
High temperatures on Thursday were expected to be between 52 and 57 along the coast and in the western valleys, 48 to 53 near the foothills, 58 to 63 in the deserts and just 38 to 48 in the mountains.
The storm system could bring light to moderate showers west as the mountains as early as Wednesday afternoon, although most of the showers should hold off until late Wednesday then continue throughout Thursday, forecasters said.
Thunderstorms could be possible Thursday afternoon as cold and unstable air moves into the area.
Rainfall amounts could range from less than a quarter-inch in the mountains, one- to three-quarters of an inch along the coast and in the valleys and from three-quarters of an inch to one-and-a-half inches in the mountains.
Several inches of mountain snow could accumulate in altitudes higher than 5,000 feet. The snow level was expected to drop to between 4,000 and 4,500 feet by Thursday and down to 3,500 feet in some mountain areas.
Forecasters said the freezing temperatures coupled with slick roads may make travel in the mountains hazardous.
Gusty, west to southwest winds were also expected to blow through the county's mountain and desert areas, according to the NWS.
