A cold storm system will arrive in San Diego County Tuesday, bringing widespread rain and thunderstorms throughout the region along with low-elevation snow in the mountains, according to the National Weather Service.
The low-pressure trough sweeping in from the northwest is expected to drop high temperatures to roughly 20 degrees below normal on Wednesday and Thursday, forecasters said.
Light rain will develop Tuesday night, then become widespread Wednesday morning.
Rainfall totals through Friday are expected to be 1 to 1.5 inches in coastal areas and the western valleys, up to 2 inches in the mountains and between one-tenth of an inch and three-tenths of an inch in the deserts, according to the NWS.
A wind advisory will be in effect from 10 a.m. to 10 p.m. Tuesday in the deserts. Winds out of the west will be between 25-35 mph, with gusts possibly reaching 60 mph.
Thunderstorms will be possible Wednesday and Thursday throughout the county.
Snow levels will drop to about 4,500 feet Tuesday night, then plunge to 4,000 feet on Wednesday and 3,500 feet on Thursday and Friday.
Areas near the peak of Palomar Mountain are forecast to get between 18 and 24 inches of snow, while 8-12 inches of white powder is forecast for Mt. Laguna and 4-6 inches is expected to fall in Julian.
A winter storm warning will be in effect from 10 p.m. Tuesday through 10 p.m. Thursday in mountain locales above 3,500 feet.
NWS officials warn that the falling snow could reduce visibility and make travel difficult on major mountain passes, including Interstate 8. Strong winds could also impact mountains areas and blow down tree limbs.
"If you must travel, keep an extra flashlight, food and water in your vehicle in case of emergency," the NWS said in a statement.
Highs temperatures on Tuesday are expected to be in the low-60s in coastal areas, the low-50s to low-60s in the western valleys, the mid-40s to low-50s in the mountains and the mid-60s to low-70s in the deserts.
Scattered showers are expected on Thursday and Friday before the storm exits by Saturday morning, forecasters said.
