Expires:No;;870014 FXUS66 KSGX 061613 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 913 AM PDT Sun Apr 6 2025 .SYNOPSIS... Warm and fair weather will prevail through the week. Areas of low clouds and fog may return to the coastal areas by Monday morning. Inland highs will be 10 to locally 20 degrees above normal Wednesday through Friday. Cooler next weekend, though it is uncertain how much cooling will occur. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... This morning...Under sunny skies, temperatures are mostly a few degrees higher than at this time yesterday. Today's high temperatures will be 5-10 degrees warmer than yesterday as a transient ridge moves over the region from the west. Sfc pressure gradients are still weakly offshore but are trending onshore. The sea breeze will likely be stronger than yesterday and high- resolution ensemble models show a 40-60 percent chance of low clouds and fog in the coastal areas between 5 am and 10 am Monday as the marine layer returns. For Monday and Tuesday...Inland temperatures continue the upward trend while the upper level ridge weakens in response a low pressure trough moving inland to the north. The resulting onshore flow and the return of the marine layer will moderate temperatures in the coastal areas and western portions of the inland valleys. Daytime temperatures will range from the upper 60s at the beaches to the low 80s in the inland valleys. The upper deserts will be in the upper 70s to lower 80s and the lower deserts will be in the low to mid 90s. For Wednesday through Friday...A large-amplitude ridge of high pressure builds over the western states. This will bring significantly warmer conditions and a reduction in the marine layer presence, limiting the nocturnal low clouds and fog to the immediate coastal areas. Thursday will likely be the warmest day, with daytime high temperatures in the low 90s for portions of the inland valleys and upper deserts. High temperatures in the lower deserts will be near 100 degrees at some locations. The national Blend of Models shows a 55-85 percent chance of 100 degrees or more on Thursday in the lower deserts. It also shows a 70-90 percent chance of 90 degrees or higher in the IE and upper deserts. Friday will not be quite as warm as the upper level ridge begins to shift eastward and heights/thicknesses begin to lower as a trough of low pressure approaches from the northwest. The trough will take control of SoCal weather for next weekend, bringing stronger onshore flow with more clouds and lower temperatures. By next Sunday, temperatures west of the mountains will be back down to the 60s and 70s. In the high deserts, temperatures will be back down to the 70s and in the lower deserts the upper 80s to near 90. There is still significant uncertainty in the forecast details for the weekend due to the spread in the ensemble member solutions. && .AVIATION... 061530Z...VFR and clear skies prevail today with typical afternoon seabreeze. Patchy low clouds redevelop tonight after 08-10z with slightly more coverage than has been seen the past several days. Bases around 500-1000ft MSL with tops to 1000-1500ft MSL. There is a 40-60% chance for a CIG for at least an hour at KSAN between 12z- 16z, with a 30-40% chance for KCRQ and a 40-55% chance at KSNA for the same time period. Localized areas of FG with VIS down to 2-3SM possible. Any low clouds/FG that do develop will generally clear to the beaches by 16z Monday, with full clearing by 18-20z. && .MARINE... No hazardous marine conditions are expected through Friday. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ PUBLIC...PG AVIATION/MARINE...Zuber