Scattered showers over the coastal waters will spread into coastal areas early this morning. The next low pressure system from the northwest will bring more widespread showers late this afternoon into Friday. With snow levels lowering to around 6000 feet late tonight, there could be moderate to heavy snowfall in the mountains above 6500 feet. For Friday night into Saturday, the most widespread showers are expected for the mountains with snow levels rising to around 7000 feet by late Saturday afternoon. Then dry with warming for Sunday through Thanksgiving with Thanksgiving high temperatures a few degrees above average to 4 to 8 degrees above average for the inland valleys and portions of the mountains.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
(today through Saturday), Early this morning, scattered showers will develop over the coastal waters and spread into coastal areas with rainfall of one-tenth inch or less. For this afternoon, scattered mostly light showers could develop in advance of a colder low pressure system moving southward just off the California coast.
The most widespread and heaviest precipitation is expected with the cold front this evening with showers continuing overnight. There is also a slight chance of thunderstorms for tonight. The snow level will rise to around 7000 feet for late this afternoon, then fall to around 5500 to 6000 feet for early Friday morning. The snow level will then gradually rise to around 7000 feet for late Saturday afternoon. South to southeast winds will develop and strengthen ahead of the cold front for late this afternoon and evening across the coastal waters and adjacent coastal areas with gusts to 25 to 30 mph.
Through Saturday, rainfall and liquid-equivalent above the snow level could range from around 1 inch at the coast to 1.5 to 2 inches for the mountains with locally greater amounts. Chances for one inch or more of rainfall or liquid-equivalent above the snow level through Friday night ranges from around 30 percent near the coast to 50 to 70 percent in the mountains. Through Friday afternoon, snowfall of 3 to 6 inches is expected from 6000 to 7000 feet, 6 to 10 inches from 7000 to 7500 feet, and 10 to 14 inches above 7500 feet. Scattered snow showers will continue for Friday night into Saturday with additional snowfall of 2 to 5 inches.
(Sunday through Wednesday), There will be high pressure off the West Coast with generally northwest flow aloft across California. There will be dry weather with a warming trend for Sunday through Thanksgiving. High temperatures on Sunday of a few to around 5 degrees above average will warm through Thanksgiving with Thanksgiving high temperatures a few degrees above average to 4 to 8 degrees above average for the inland valleys and San Diego County mountains.
High temperatures on Sunday will range from the lower to mid 60s near the coast to the mid 60s to around 70 for the valleys with the lower to mid 70s for the lower deserts. High temperatures on Thanksgiving will range from around 70 near the coast to the 70 for the valleys with the mid to upper 70s for the lower deserts.
201030z, Increasing low clouds mainly between 2500-3500 feet MSL along with SCT -SHRA in coastal areas through 14Z. SCT-BKN low clouds 2500-3500 feet MSL continue into afternoon, with increasing -SHRA. Cloud bases will lower to 2500 feet MSL, then 1500 feet as a band of -RA moves southeast through the region starting at 22Z vcnty KSNA and ending around 09Z vcnty KSAN, but with SHRA following the band. +RA and any TSRA (15% chance) would briefly drop cigs below 1000 feet MSL and vis 1-5SM. Widespread mountain obscuration during the band's passage.
Strengthening southerly winds gusting to 25 knots this afternoon will turn westerly tonight, generating choppy seas. Check the Small Craft Advisory for details. There is also a slight chance of thunderstorms late this afternoon through Friday afternoon. Any thunderstorm could bring lightning, gusty winds, choppy seas, and a waterspout.
Ca, Winter Storm Warning from 4 PM this afternoon to 4 PM PST Friday for Riverside County Mountains-San Bernardino County Mountains above 6500 feet.
PZ, Small Craft Advisory from 4 PM this afternoon to 1 AM PST Saturday for Coastal Waters from San Mateo Point to the Mexican Border and out to 10 nm-Waters from San Mateo Point to the Mexican Border Extending 10 to 60 nm out including San Clemente Island.
