Get ready for some stormy weather, San Diego

San Diego will get three storms by late next week.
(Howard Lipin / The San Diego Union-Tribune)

San Diego’s 3.5-inch rain deficit could cut by more than half over the next week by a series of winter storms, the largest which will drop a foot of snow in the mountains and possibly that much in Julian, says the National Weather Service.

The first system will arrive before dawn on Saturday and will produce about 0.40 inches of precipitation by the time it fades away. The mountains could get 0.75 inches. San Diego’s daytime high will only reach 58 degrees, which is seven degrees below average.

The second system, now taking shape in British Columbia, is much bigger and far colder. It will begin to move ashore late Sunday night and will slam the county on Monday, generating nearly an inch of rain in San Diego and higher amounts inland. The rain will turn to snow as cold air floods into Southern California.

“The snow level could get down to 3,000 feet, and there will be snow on Interstate 8,” said Miguel Miller, a weather service forecaster. “If you don’t need to drive in that area on Monday, you shouldn’t.”

Forecaster models suggest that Mount Laguna and Palomar Mountain will get 1 foot of snow, and a similar amount will hit Julian, which rarely receives that much from a single storm. The daytime high in San Diego Monday will be 55.

The skies should clear by late Tuesday or early Wednesday. But a potentially large storm out of the northwest will swirl into the county late Thursday and produce about an inch of rain into Friday along the coast.

“This will be a very wet system for Northern California and could be for Southern California as well,” Miller said. “We could end up getting an atmospheric river.”

In this region of the world, an atmospheric river generally refers to plumes of moisture from the west-northwest that draw additional moisture from the sub-tropics, making many storms much bigger.

San Diego is in need of rain. The city has recorded only 0.99 inches of precipitation since October 1 — which is roughly 3.5 inches below normal. Miller says the three storms could collectively produce 2.5 inches of rain.