Patchy clouds and fog linger near the coast with some higher level clouds for inland areas today. Warm weather will continue inland while temperatures stay near average at the coast this weekend. A trough off the Pacific will bring cooler and breezier weather by the middle of the week with a chance of light showers. Highs will generally stay near to slightly above average with dry weather by the end of the week as high pressure builds in from the southwest.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
A trough off the California coast will move ashore today. This has begun to stream in mid-level clouds across SoCal, while the marine layer stays thin with foggy conditions near the San Diego County coastline. Another day, another 1/16th of a mile visibility at San Diego Int'l. Low clouds may locally stick near the coast through the day, while higher clouds stay with us this morning and scatter a bit more this afternoon. Pressure heights will lower a bit over the weekend, so some improvements in visibility will occur along the coast, with foggiest conditions becoming more confined to the adjacent coastal valleys. Otherwise, dry weather will continue with highs remaining 5-15 degrees above normal for inland areas; temperatures will be in the 60s and 70s for areas below 5,000 feet and near 80 across the Coachella Valley and Anza- Borrego Desert.
The active pattern over the Pacific will generate another trough of low pressure moving into our area by Tuesday. Confidence is increasing on seeing clouds and a 30-50% chance of showers by Tuesday afternoon through night across our region. Most of the shower activity will occur along and west of the mountains, with minor chances for the deserts. Whatever does fall will be light. Most areas will see a few hundredths while coastal slope regions will see near one tenth of an inch. As the trough moves through, expect winds to pick up in our generally windier areas of the mountains and deserts by later in the afternoon on Tuesday into the overnight hours. Noticeably cooler conditions will occur by Wednesday for the mountains and deserts as well where temperatures will lower into the 70s for the lower deserts and 50s for the high desert. Other than this, Christmas Day will be dry and seasonal.
High pressure to the southwest will slowly regain momentum by later in the week per latest cluster ensemble guidance. This will diminish chances for precipitation as well as return temperatures to above average across the inland valleys.
211100z. Coasts, A patch of low clouds based at 200-300 feet MSL has filled in across coastal San Diego County, with VIS at or below 1/2 SM. Light offshore flow is limiting inland extent and has helped nudge the clouds westward and even offshore in spots. KCRQ has since cleared while KSAN remains solidly within the fog deck. Orange County remains free of low clouds for now with areas of VIS 3-6SM in BR but a deck of low clouds based at 200ft MSL with dense fog (VIS <1/2 SM) is approaching from the west and should arrive by 12z. Once this arrives, KSAN and KSNA could continue to see VIS <1/2 SM through at least 15z while KCRQ looks to stay just to the east of the fog, but will be uncomfortably close. Some VIS improvements and clearing may begin to occur around 15-16z but could stick around at KSAN/KSNA through 18z. Mostly clear conditions expected thereafter though some patches of low clouds/fog could linger into the afternoon along the beaches. Low clouds and fog look to make a resurgence in the evening, possibly as early as 00-01z, with much higher confidence in CIGs after 05-06z Sunday. Bases and VIS restrictions will likely be similar to this morning's but bases may be ~100ft or so higher.
.Valleys/Mountains/Deserts, VFR conditions will prevail through early Sunday morning, but with an increase in high clouds above 20000 feet MSL for Saturday morning/afternoon.
Patchy dense fog with visibility below 1 NM at times will continue through Saturday morning, especially for the nearshore waters. Rounds of overnight/morning fog remains possible through at least Tuesday.
Long period west swells of 8-11 feet are expected Sunday through Tuesday night, highest in the outer coastal waters where a Small Craft Advisory has been issued. 8-9 feet waves possible within 10-30 NM of the coast but should still be enough offshore to limit any nearshore impacts. Wind gusts of 20-25 kts are expected Tuesday night in the outer coastal waters.
Long period (16-19 second) west to northwest swells (280-290 degrees) arrive early Sunday and into next week, resulting in high surf of 6-12 feet with locally higher sets continuing through Wednesday. This will make swimming hazardous and pose a coastal flooding threat. See the High Surf Advisory for more details.
Ca, Dense Fog Advisory until 9 AM PST this morning for San Diego County Coastal Areas-San Diego County Valleys.
High Surf Advisory from 10 PM this evening to 4 AM PST Wednesday for Orange County Coastal Areas-San Diego County Coastal Areas.
Dense Fog Advisory until 9 AM PST this morning for Orange County Coastal Areas-Orange County Inland Areas.
PZ, Small Craft Advisory from 10 PM this evening to 4 AM PST Wednesday for Waters from San Mateo Point to the Mexican Border Extending 30 to 60 nm out including San Clemente Island.
