Cooler conditions expected for much of this week, with temperatures fluctuating between below average and near average. Increased winds and periods of precipitation expected through Wednesday. Dry conditions and a little warmer Friday and Saturday. Potential for more widespread precipitation, gusty winds, and a return to cooler conditions for early to mid-next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Dry conditions will continue through are expected through much of today. A few light pre-frontal showers may develop after sunset but the main band of rainfall is still on track to move through Wednesday morning through mid-afternoon. Light to moderate rain is expected with rainfall rates mainly 0.20-0.40" per hour, with a 10 percent chance of local rainfall rates exceeding 0.50" per hour. Forecast rainfall totals for the San Bernardino County mountains and Orange County are mainly 0.30-0.75", locally over an inch for the eastern San Gabriel mountains. For San Diego county and Inland Empire, rainfall totals are still expected to be 0.25" or less, except for northern San Diego county and near the LA county line where rainfall totals could be locally closer to 0.50". The rain band associated with the passing front is expected to move quickly from northwest to southeast. There is a 10-15% chance of thunderstorms with the main rain band, with those higher rainfall totals most likely where any thunderstorms or convective showers develop. After the passage of the main front isolated light showers are expected mid-Wednesday morning for Orange County and Wednesday afternoon for San Diego County.
Snow levels during the highest chance of precipitation are expected to be 6500-7000 ft. Latest forecast has 1-3" of snow from Tuesday night through Wednesday, for most locations. Portions of the eastern San Gabriel mountains are now expected to exceed 3 inches of snow, but those higher accumulations will be above 7000 feet. Additionally, gusty southwest to west winds are expected in the mountains and deserts. Winds have already begun to increase this afternoon and are expected to peak Wednesday morning, diminishing into Wednesday afternoon. Strongest winds are likely to occur on the desert mountain slopes and below passes. Current forecast has peak wind gusts of 40 to 60 mph.
Latest high resolution model guidance is indicating dry conditions for Thursday so chances of precipitation have been removed from the forecast. Weak transitory ridging is expected to develop Friday afternoon into Saturday, bringing a brief period of dry and slightly warmer weather. A more robust trough dropping out of the Gulf of Alaska will bring additional chances of precipitation and gusty winds beginning as early as Sunday evening. Wet and cool weather looks like it will continue through the middle of next week with the potential for much higher rain and snow amounts.
102115z. A mix of ceilings will continue to persist today. A low bottom layer 2500-4000 ft MSL will continue to fluctuate between SCT- BKN through late this evening, and BKN-OVC clouds 10-18k ft will continue to stream in. Low level clouds will gradually lower to 1500- 2500 ft MSL and move to cover the entire coastal basin overnight. A band of -RA will move through the region 08-18Z Wed, followed by more SCT/ISO -SHRA and gradually improving conditions through Wed evening, with CIGs/VIS briefly lowered in RA/SHRA and areas of mountains obscured.
Breezy southwest winds continue along the northern slopes of the San Bernardino Mountains into the High Desert through Wed afternoon. Winds gusting 35-45 kts with isolated gusts to 55 kts along wind prone mountain slopes and passes will produce MOD up/downdrafts in lee of ridges along with patchy reduced vis 3-5SM in BLDU in the desert.
Marine conditions will be hazardous to small craft this evening through early Wednesday morning as southerly wind gusts increase, with gusts to 25 knots throughout the coastal waters. See the Small Craft Advisory for more details. Winds diminish gradually over the day Wednesday. Following that, no hazardous marine conditions are expected through Saturday.
Increasing westerly swell will lead to elevated surf of 4-6 feet for San Diego County beaches Wednesday, with localized sets to 7-8 feet. Surf peaks Wednesday evening/night then gradually diminishes Thursday.
Ca, Wind Advisory until 1 PM PST Wednesday for Apple and Lucerne Valleys-San Bernardino County Mountains.
PZ, Small Craft Advisory from 7 PM this evening to 5 AM PST Wednesday 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.
