475 FXUS66 KSGX 122022 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 122 PM PDT Sat Jul 12 2025 .SYNOPSIS... Slightly cooler conditions today followed by a slight rebound in temperatures for Sunday and Monday. Gradual cooling back to near average for mid July expected for the middle to the end of next week. While chances are still low and uncertainty remains, some confidence is increasing for the potential of monsoonal thunderstorms over the mountains late next week. Night and morning low clouds will spread across the coastal areas and into the western valleys late each night. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... The dominant upper ridge in control of the region`s weather is currently displaced just off the California and is also a tad weaker than it was earlier in the week. This and a modestly deep marine layer to ~2000ft is limiting high temperatures to 5 to locally 10 degrees below average west of the mountains, while the deserts stay ~5 degrees above average. Coasts today top out in the 70s with inland valleys generally in the mid to upper 80s, while the Inland Empire will reach the low 90s. Deserts staying hot with high temperatures 105 to 110 degrees. The ridge restrengthens and spreads back overhead Sunday and Monday, leading to a rebound in temperatures up about 5 degrees warmer than today. The marine layer depth decreases some with the building ridge, but will still be around 1500-2000ft deep. By mid-late Monday, a shortwave trough rounding the upper ridge will be on the southern periphery, which looks to place it across northern Baja. While some monsoonal moisture will likely accompany this shortwave, any convection will likely be limited to the mountains in northern Mexico. While unlikely, a stray storm over the extreme southern San Diego County mountains cannot be ruled out. By Tuesday/Wednesday, this disturbance will have passed but should leave the ridge weakened and displaced back to the eastern Four Corners Region. This opens the door for a series of disturbances Thursday through the end of the week. While model guidance continues to show a fairly vast range of solutions in the exact placement of the ridge and corresponding tracks of the aforementioned disturbances, more ensemble members (notably out of the higher- resolution ECMWF which were previously more dry in the last several runs) are starting to coalesce around the chance of diurnal monsoonal thunderstorms in the mountains possible each afternoon Thursday-Saturday. Significant uncertainty in timing is muddling the view here and a few more days of seeing how the pattern evolves is necessary to say with much confidence who will see, or even if, thunderstorms occur. There is still good agreement in a gradual cooldown as a result of this pattern, which has many locations 5 to 10 degrees cooler on Wednesday compared to Monday. && .AVIATION... 122010Z....Coast/Valleys...Skies have mostly cleared this afternoon, with the exception of areas near Point Loma in San Diego. Intermittent SCT-BKN clouds near 1,500 ft MSL expected VCTY KSAN through the afternoon hours. BKN-OVC low clouds will surge inland again this evening around 00-02Z. Bases starting near 1,500-1,800 ft MSL will lower closer to 1,000-1,300 ft MSL after 04Z Sun with similar inland extent of this morning. Confidence increasing VCTY KONT seeing BKN cigs 700-900 ft MSL after 10Z Sun. Similar clearing pattern expected on Sunday. Mountains/Deserts...VFR conditions and unrestricted VIS through this weekend. && .MARINE... No hazardous marine conditions expected through the middle of next week. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ PUBLIC...Munyan AVIATION/MARINE...APR