Rain on car's side mirror
Rain on a San Diego freeway. Photo by Alexander Nguyen

Dramatically cooler weather will move across Southern California Thursday, with a pair of storm systems bringing “sharply” colder temperatures, rain and mountain snow.

A winter storm watch will be in effect in the San Diego and Riverside County mountains from late Thursday night through Sunday morning, with the National Weather Service warning of possible heavy snow and strong winds.

Forecasters said as much as 2 feet of snow could fall above 6,000 feet, with 1 to 5 inches possible at lower elevations down to 4,000 feet.

According to the weather service, the first system will arrive Thursday night into Friday, followed by a second round of precipitation Friday night into Sunday.

“Snowy and windy conditions with significant reductions in visibility are possible, especially during the morning commute on Friday,” according to the NWS.

A wind advisory will also be in effect for Riverside and San Diego County mountains, along with San Diego County desert areas, from noon Thursday through midnight Thursday night. Forecasters said wind gusts of up to 70 mph are possible in some areas.

Forecasters said San Diego and western Riverside counties can expect falling temperatures starting during the day Thursday, then a more dramatic drop.

“The weather will turn sharply colder Friday through Sunday as a series of shortwaves in cold northwest flow brings rain, wind and mountain snow,” according to the NWS.

Highs Thursday are forecast to be 63 near the coast, 67 inland, 67 to 72 in the valleys, 62 to 70 in the mountains and 83 to 88 in the deserts.

Weather Service officials said the San Diego County mountains will likely receive the most precipitation during the first wave of the storm, with 1 to 1.75 inches of rain possible, while coastal and valley areas could get between a quarter-inch to an inch of rain. Desert areas will see 0.1 to 0.25 inches, forecasters said.

As the second front moves into the region Saturday, more rain will fall in mountain areas, along with another quarter-inch possible in valley areas. The snow level, meanwhile, will drop to about 3,500 feet, with “several more inches” of snow likely.

City News Service contributed to this article.