Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
007 FXUS66 KSGX 060417 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 917 PM PDT Sun May 5 2024 .SYNOPSIS... Chilly overnight temperatures tonight into Monday morning, with lows 5 to 10 degrees, locally up to 15 degrees in the deserts, below normal. Gradually warming conditions expected through mid-week. Periods of breezy westerly winds expected in the afternoons and evenings in the mountains and deserts early this week, with the potential for offshore winds Wednesday. Warmer and dry conditions are expected into next weekend. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Satellite imagery at 9 PM is showing mostly clear skies, with some clouds against the coastal slopes of the mountains. Winds have died down, with only a few gusts 35-40 mph below the San Gorgonio Pass and in the High Desert. Winds will continue to weaken through midnight into early Monday. A peak wind gust summary and rainfall totals have been headlined on our weather.gov/sandiego homepage. Chilly conditions expected overnight by May`s standards. Lows Monday morning could be up to 15 degrees below average for this time of year in the deserts. There is a 20% chance lows in portions of the High Desert will fall to the mid-30s. Winds are expected to weaken but not completely diminish in the High Desert which will be a limiting factor in how cold it gets there overnight. Daytime temperatures will rebound under mostly sunny skies Monday. Highs temperatures are expected to be 3 to 10 degrees warmer than Sunday for the coast and valleys; 15 to 20 degrees warmer than Sunday in the mountains and High Desert; and 4 to 12 degrees warmer than Sunday in the lower deserts. That translates to highs in the mid to upper 60s along the coast, low to mid-70s for the valleys and High Desert, mid-80s for the low desert, and mid-50s to 60s for the mountains. From the previous discussion issued at 2 PM May 5... 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. 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... 060400Z...Coasts/Valleys/Foothills...Patchy low clouds will occur through 16Z Mon with bases 2500-4000 ft MSL and most prevalent near the foothills. Most vis will remain above 5 miles. Mostly clear skies will prevail after 16Z Mon, continuing through Mon evening with unrestricted VIS. Mountains/Deserts...Areas of gradually decreasing W/NW winds with gusts 25-40 knots will continue through 11Z Mon with MOD UDDFS. Local terrain obscurations will occur below 5500 ft MSL on the coastal mountain slopes through 09Z Mon in decreasing clouds. Otherwise, mostly clear skies with unrestricted VIS will prevail through Mon evening. && .MARINE... West to northwest winds will gradually diminish overnight, with some gusts to 25 knots in the outer coastal waters (30-60 NM from the coast) until around or shortly after midnight. West to northwest winds will gust to around 20 knots Monday and Tuesday afternoon and evening. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...None. 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...CO/EA AVIATION/MARINE...Maxwell