Another winter storm is setting up to deliver a powerful punch to San Diego and Southern California.
The weather system will bring heavy periods of rain and high winds as well. For the daytime on Wednesday, county, scattered, isolated showers are possible. Shower activity should pick up during the late afternoon or early evening, then continue with heavy rain at times, through the night.
A second, lighter storm should hit on Thursday by midday, bringing showers through Christmas Day and into Friday morning.
Expect about 1 inch of rain at the coast by Friday, with 2-3 inches of rain in the mountains. The snow level will be quite high with this storm, so expect a lot of melting snow to add to the runoff caused by the heavy rain. This will likely cause localized flooding and debris flow, especially in the recent burn areas.
Snow will accumulate above 6,000 feet overnight, in heavy amounts at the highest elevations to our north. As colder air moves in, the snow level should drop, first to about 5,000 feet on Christmas day, then down to 4,000 feet on Friday. In all, we could get as much as 1-2 feet of new snow at Big Bear and Wrightwood, and up to 6 inches on Mount Laguna and Palomar Mountain.
Strong, gusty winds will accompany the snow and rain in the mountains through Thursday, adding to the hazardous driving conditions. Chains will likely be required by Wednesday night on the highest mountain roads. There could also be closures or long delays by Wednesday night on Interstates 5 and 15 around Los Angeles.
A flash-flood watch has been issued for Wednesday night through Thursday for all of Southern California and a wind advisory will be in effect for in all mountainous areas.