Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
178 FXUS66 KSGX 141639 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 939 AM PDT Fri Jun 14 2024 .SYNOPSIS... Above average temperatures are expected for inland areas today and Friday. Several degrees of cooling is expected for Sunday and Monday, before another round of more gradual warming for Tuesday through Friday. Night and morning low clouds will continue along the coast, spreading into portions of the valleys at times. There will be stronger and gusty southwest to west winds for the mountains and deserts for this weekend during the late afternoon through late evening each day. Daytime relative humidity will fall to 10 to 15 percent in the same areas impacted by wind, creating elevated fire weather conditions. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Low clouds have been rapidly clearing to the coast this morning with some beaches in San Diego seeing sunshine. With increasing high pressure aloft, low cloud and fog coverage will become more confined to the coast, potentially reaching into portions of the far western valleys tonight into Saturday morning. Areas of patchy fog are possible tonight into early Saturday morning, especially near mesas and other higher coastal terrain. The marine layer is expected to begin to deepen again Sunday and Monday, with higher chances of reaching further into the valleys during that time. High temperatures today are expected to be a few degrees warmer than yesterday at the coast with 5 to 12 degrees of warming for inland areas. An additional few degrees of warming is expected for inland areas tomorrow, with 3 to 7 degrees of warming for coastal areas. High temperatures for the hottest locations in the lower deserts around 115 and in the Inland Empire around 100. Areas of moderate to locally major heat risk are expected for the low deserts today and Saturday with moderate heat risk in the Inland Empire Saturday. With these hot conditions it`s recommended to avoid strenuous outdoor activities if you can, especially between the hours of 10 am and 5 pm, and stay hydrated. Sunday will be noticeably cooler across the area as a broad troughing pattern holds over the Western United States. Widespread cooler conditions will maintain into Monday. In addition to cooler conditions and increased low cloud coverage, the increase in onshore flow will generate gusty southwest to west winds for the mountains and deserts each late afternoon through late evening for the weekend with gusts to 30 to 40 mph with isolated gusts to around 50 mph in the northern Coachella Valley below the San Gorgonio Pass. By Tuesday, guidance is indicating gradual warming will begin for areas in and west of the mountains. That warming is expected to spread to the deserts by Wednesday with continued warming for all areas into at least next Friday. By next Thursday, there is over 60% chance that above average temperatures will return to the lower deserts, with chances increasing to over 90% for next weekend. This is a good indicator that summer is finally settling in, with the potential for a longer duration heat wave for next weekend into the following week (week of June 23). && .AVIATION... 141600Z...Coast/Valleys...Rapid clearing this morning across San Diego county coast. This will expand into Orange County through 17z. Less marine layer is forecast Friday night and Saturday and more confined to the immediate coast as upper ridge warming builds overhead in the wake of the upper trough exiting Arizona. Chances for low cloud formation is 60 percent for Saturday morning at KCRQ and KSAN, and 30 percent for KSAN and ceilings will be lower near 1000 feet and 30 percent chance of IFR ceilings and MVFR visibility. Mountains/Deserts...SKC with unrestricted VIS. Gusty W-NW winds picking up after 20z Fri, with peak surface wind gusts of 25-35 knots expected. MOD UDDFS expected over and east of the mountains. && .MARINE... Northwest winds may gust to around 20 knots at times in the far outer waters near San Clemente Island each afternoon and evening Saturday through Monday. No other hazardous marine conditions expected. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Heat Advisory from noon to 8 PM PDT Saturday for San Bernardino and Riverside County Valleys-The Inland Empire. Excessive Heat Warning until 8 PM PDT Saturday for Coachella Valley-San Diego County Deserts-San Gorgonio Pass Near Banning. PZ...None. && $$ PUBLIC...CO AVIATION/MARINE...Tardy