Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
957 FXUS66 KSGX 052045 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 145 PM PDT Sun May 5 2024 .SYNOPSIS... Cool temperatures and passing clouds are expected today. Strong winds over the mountains and deserts will continue through this evening. Dry weather with slow warming will prevail through midweek, with little day-to-day change Thursday into next weekend. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... A 543 DM low is progressing into the Great Basin today and a shortwave is rounding the base of the trough over the Mojave Desert. Showers have diminished and pockets of shallow cumulus clouds are left in the wake of a cold front that moved through the region early this morning. Strong west to northwest winds will continue this afternoon over the mountains and along the desert slopes, with peak wind gusts up to 55 mph. Winds will diminish tonight as the parent low moves quickly eastward. Today will be the coolest day of the week for most areas, with highs topping out 3-6 degrees below normal across the coast and western valleys, and 10-20 degrees below for the foothills, mountains and deserts. Highs will reach the 60s for the coastal areas and valleys, 40s in the mountains, upper-50s to low-60s in the High Desert, and mid to upper-70s in the lower deserts. Southern California will remain under weak cyclonic flow through at least Wednesday as a ridge builds near the Pacific Northwest and a strong upper low is centered over the central US. Much warmer temperatures are expected on Monday, with more gradual warming occurring on Tuesday and Wednesday. Breezy onshore west to northwest winds will develop each afternoon and evening over the mountains and deserts, with peak gusts approaching 40 mph. For the second half of the week, ensemble guidance is pointing towards a positively-tilted shortwave breaking off from the parent low over the central US, and retrograding towards the Desert Southwest. A period of offshore winds are expected on Wednesday as this low strengthens, but will turn predominantly back onshore for Thursday and Friday as the low becomes centered near the Four Corners region. Otherwise, little day-to-day change is expected temperature wise Wednesday through Friday, with highs remaining within a few degrees of seasonal averages. Marine layer low clouds will continue for the coastal areas and portions of the valleys each night and morning, potentially deepening and spreading further inland by next weekend. && .AVIATION... 051930Z...Coasts/Valleys/Foothills...FEW-SCT clouds, locally BKN-OVC with bases 3000-4000 FT MSL continue through this afternoon and early evening. Skies clearing generally between 06-09z tonight. Some patchy low clouds possible overnight but CIGs are unlikely. W-NW winds remain elevated this afternoon, with peak wind gusts of 25-30 kts possible along the immediate coast. Mountains/Deserts...Expect another round of strong W-SW winds 20-35 kt with gusts of 45-60 kt this afternoon. Areas of MOD-STG up/downdrafts and LLWS over/east of mtns. SCT-BKN clouds at/abv 10000 ft MSL through this evening. && .MARINE... Northwest winds gusting 25 to 30 knots will continue through this evening, which will generate hazardous boating conditions, especially in the outer waters. Northwest winds gusting up to 20 knots will be possible over the outer waters each afternoon and evening for Monday through the middle of next week. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory until 8 PM PDT this evening for Apple and Lucerne Valleys-Coachella Valley-Riverside County Mountains-San Bernardino County Mountains-San Diego County Deserts-San Diego County Mountains-San Gorgonio Pass Near Banning. PZ...Small Craft Advisory until 10 PM PDT this evening for Coastal Waters from San Mateo Point to the Mexican Border and out to 30 nm. Small Craft Advisory until 3 AM PDT Monday for Waters from San Mateo Point to the Mexican Border Extending 30 to 60 nm out including San Clemente Island. && $$ PUBLIC...EA AVIATION/MARINE...Adams