Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
499 FXUS66 KSGX 030331 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 831 PM PDT Thu May 2 2024 .SYNOPSIS... Periods of low clouds and fog are expected each day west of the mountains, most widespread in the nights and mornings. A weather system passing to our north will increase cloud coverage for inland areas this weekend. That system will also bring gusty winds to the mountains and deserts, cooler conditions, and periods of showers to areas over and west of the mountains. Drier and warmer conditions are expected through the middle of next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .Evening Update... The marine layer stuck tight near parts of the coast today with some poor unfortunate souls trapped under the thick cloud deck for much of the day, while areas near Carlsbad and Encinitas reported some clearing, albeit only for a half hour or so. Friday looks to be a similar day across Southern California, with a bit better clearing by the afternoon for those under the sea and at the coast, per latest HREF guidance. No significant changes to the forecast are expected for the weekend. Colors of the wind will be the most significant impact with this late season system, so wind advisories have been placed for portions of the mountains into the deserts. There is a moderate to high chance in seeing winds in excess of 45 MPH for these areas by Sunday afternoon and evening, as well as winds over 20 MPH closer to the coast. Be careful if voyaging in your car (or canoe). A trough looks likely to weakly hang on into next week. Snow White will start to serenade the birds, bunnies, and deer by next week as sunnier and warmer weather returns to the region. Breezy west winds will occur each day across the mountains and deserts near 20-30 MPH at times. Overall, nice weather for outdoor activities such as apple picking... .Previous Discussion (139 PM Thursday)... As of 1 PM this afternoon, low clouds have been slow to clear. The Inland Empire is finally seeing some sunshine, but most of the coast, Orange County, and western valleys in San Diego County are still under the cloud deck. The trend is for clearing to occur in the valleys, but clouds could stick along some beaches all afternoon. Low clouds are expected to spread into much of the coastal basin overnight into Friday morning and again Friday night into Saturday morning. A low pressure system will move into the Pacific Northwest Saturday, before digging south in the Great Basin Sunday. This will increase onshore flow for Southern California this weekend and as a result cloud coverage (especially for the valleys and mountains) will be more persistent, high temperatures will take a dip, winds will increase, and areas of showers are expected. Periods of gusty southwest to west winds over the mountains, through passes, and into the deserts will be the main weather hazard. Winds will begin to increase Saturday afternoon, peak Saturday night into Sunday, before slowly tapering off Sunday night into early Monday. Peak gusts of 55 to 65 mph are expected on the desert mountain slopes, through passes, and into portions of the deserts. Periods of light precipitation are expected for places in and west of the mountains. Coverage of the precipitation will be showery, with best chances in the mountains and 15-25 percent elsewhere. This is a fast moving system and current timing has the bulk of the shower activity occurring Saturday night into Sunday morning. Rainfall totals of a 0.15 inches or less are expected for the coast and valleys with up to 0.25 inches of rain for the coastal mountain slopes. A trace of snow is possible above 7500 ft. High temperatures Friday will be near to slightly above average. Cooler conditions are expected Saturday, with further cooling expected on Sunday. On Sunday highs will be 10 to 15 degrees below average for inland areas, up to 20 degrees below average in the mountains. Monday will be dry and much warmer, around 5 degrees warmer at lower elevations to 8 to 12 degrees warmer for the mountains with not much change for Tuesday and Wednesday, generally a few to around 5 degrees below average. && .AVIATION... 030330Z...Coasts/Valleys...BKN-OVC low clouds will continue to expand this evening and cover most areas by 08Z Fri with bases 1300- 2000 ft MSL and tops to 2500 ft. Higher terrain will be obscured at times. Most VIS below the clouds will be unrestricted, but local VIS 3-5 miles in BR will occur in the valleys 06Z-18Z Fri. Clearing will be slow Fri, mostly 16Z-19Z in the valleys and 18Z-21Z near the coast, with areas of BKN clouds continuing at the beaches Fri afternoon. Stratus will spread inland again Fri evening with slightly higher bases. Mountains/Deserts...Clear skies with unrestricted VIS will continue through Fri evening. && .MARINE... No hazardous marine conditions are expected through Saturday morning. Gusty west to northwest winds late Saturday through Sunday evening are likely to generate hazardous boating conditions, especially in the outer waters (30-60 NM from the coast). Current projections for strongest winds are on Sunday when gusts could be 25- 30 knots near San Clemente Island with a few gusts 20-25 knots near the coast. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory from 3 PM Saturday to 5 PM PDT Sunday for Apple and Lucerne Valleys-Riverside County Mountains-San Bernardino County Mountains-San Diego County Deserts-San Diego County Mountains-San Gorgonio Pass Near Banning. PZ...None. && $$ PUBLIC...APR AVIATION/MARINE...Maxwell