Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
589 FXUS66 KSGX 190917 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 217 AM PDT Sun May 19 2024 .SYNOPSIS... A persistent trough over the West Coast will continue the weather pattern we have been seeing as of late. Temperatures will remain slightly below average with gusty winds across the mountains and deserts. A weak area of low pressure will move across the region on Monday, which will bring the coolest and windiest conditions overall. Low clouds will continue nights and mornings, retreating back to the coast each afternoon. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Gusty west winds continue to gust near 25-40 MPH across most mountain and desert locations early this morning. These winds will weaken through the morning before returning by the afternoon and evening hours as a trough hangs over the western part of the country. Confidence is moderate in seeing winds peak near 40 MPH across these areas, best chance through mountain passes which may see winds near 45-50 MPH. Low clouds have filled in much of the coastal basin this morning with NBM and HREF probabilities pointing to a fairly good chance in clearing again at the coast by this afternoon. The deep marine layer will maintain itself through Monday, so areas of drizzle will be possible west of the mountains today and tomorrow mornings. An area of low pressure off the coast to our southwest will combine with the mean flow and deepen the trough over our region on Monday. This will further cool the region and increase winds over mountains and deserts. Confidence increases for these areas to see wind gusts over 40 MPH and over 55 MPH in wind-prone mountain passes; the San Gorgonio Pass which has a 70-80% chance of exceeding 55 MPH winds per latest NBM. Temperatures will be near 5 degrees below average across the coastal areas with up to 10 degrees below average for inland areas. The trough over the West Coast will continue, though not as potent as Monday. Rising heights will lead to some warmer conditions with less wind over inland regions. Little day to day weather variations can be expected from Tuesday through the week, where we will see slightly below average temperatures and May Gray conditions west of the mountains in the morning with general clearing toward the coast by the afternoons. Ensemble cluster model analysis points to possible weakening of this troughing pattern as a ridge across Mexico may begin to provide a larger influence over the southwestern U.S. && .AVIATION... 190850Z...Coast/Valleys... Stratus will continue to fill in across the valleys with bases 1400-2000 ft MSL and tops to 2700 ft MSL and higher terrain obscured. Below the cloud deck vis will mostly be unrestricted. Local -DZ could occur 12Z-16Z. Clearing will occur 16Z- 19Z in the valleys and 18Z-21Z near the coast with some locations within 5 miles of the coast having BKN CIGs continuing through the afternoon. Low clouds will spread rapidly inland after 20/01Z reaching the inland by 09Z. Bases 1500-2000 ft and tops increasing to around 3000-3500 ft MSL by Monday morning. Mountains/Deserts... Mostly clear with unrestricted vis through Monday morning. Areas of W-SW winds with gusts 30-45 kt from the mountain crests east through the desert slopes and into the deserts will continue at times through tonight, accompanied by MOD UDDFS and LLWS over/E of the mtns. && .MARINE... No hazardous marine conditions are expected through Thursday. && .BEACHES... A series of southwest swells of 2-3 ft at 16-18 seconds from 200-220 degrees will build today and continue through Tuesday, producing above normal surf of 3-5 ft with locally higher sets on exposed SW facing beaches, as well as a high risk of rip currents at all beaches. A Beach Hazards Statement has been issued for today through Monday evening. Swell and surf will slowly lower Wednesday and Thursday. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Beach Hazards Statement through Monday evening for Orange County Coastal Areas-San Diego County Coastal Areas. PZ...None. && $$ PUBLIC...APR AVIATION/MARINE...SS