Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
407 FXUS66 KSGX 272045 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 145 PM PDT Sat Apr 27 2024 .SYNOPSIS... Dry and warm conditions expected into early next week. Many areas will have to near to slightly above average temperatures Sunday through early next week. The marine layer will be shallower, with night and morning low clouds and patchy fog more confined to coastal areas. There is some uncertainty in the forecast for the latter half of the week, but dry conditions are expected with a potential for widespread above average temperatures. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Dry conditions are expected through the rest of the weekend with weaker winds and sunnier skies for much of Southern California. Weak high pressure aloft is expected into early next week, which will bring temperatures near to slightly above average for Sunday through Tuesday. Highs in the upper 60s expected near the coast, with highs in the upper 70s and low 80s in the valleys, and highs in the 90s in the lower deserts. The backside of the trough is still close enough to Southern California today to enhance the onshore pressure gradient and afternoon sea breeze. West to northwest winds across mountains and deserts will have peak gusts of 25-40 MPH through this evening. Winds will be slightly higher through the San Gorgonio Pass, with local gusts up to 55 mph possible. Onshore winds will continue to weaken into Sunday and early next week as weak high pressure aloft prevails. Periods of weak offshore flow may develop Tuesday morning near mountain foothills and below passes locally into the valleys. A trough of low pressure aloft is expected to move across the Intermountain West Wednesday, further weakening the already weak high pressure over California. This will mean a few degrees of cooling for most areas on Wednesday and the potential for additional rounds of breezy westerly winds over the mountains, through passes, and into the deserts. There is still some uncertainty surrounding the wind forecast due to uncertainty in the placement and amplitude of the passing trough. If the trough digs south into the Great Basin (supported by about a quarter of the ensemble solutions) that would bring stronger winds to Southern California in addition to the few degrees of cooling. Uncertainty in the global models remains for the end of next week. For Thursday and Friday there remains some disagreement surrounding the potential for high pressure aloft to rebuild over the West Coast in the wake of the aforementioned trough. About a quarter of the global ensemble solutions have a ridge building over the West Coast for Thursday and Friday. The remaining solutions are more in favor of a prevailing troughing pattern. The majority of solutions that support troughing are indicating conditions will remain dry into next weekend. If the troughing pattern materializes, then cooler conditions with periods of enhanced westerly winds over the mountains, through passes, and into the deserts can be expected through the end of the week. If the ridging pattern materializes, then warming conditions can be expected for the end of the week, with periods of weak offshore flow. Current forecast for the end of the week closely follows the NBM. && .AVIATION... 272025Z...Coast/Valleys/Mountains..BKN-SCT 020-040 with tops 6500 feet. Mountains obscd in clouds and fog at times. Gradual clearing from the northwest through this evening. Deserts...Mostly clear with gusty northwest winds 20-40 kt decreasing this evening. Confidence in TAF forecast of mainly SCT low clouds at KSAN this evening is moderate to high. && .MARINE... Winds and seas should subside. No hazardous marine conditions are expected through Wednesday. && .BEACHES... Elevated surf from a short-period wind swell on exposed west-facing beaches. Surf and swell will gradually subside this evening. && .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...CO AVIATION/MARINE/BEACHES...Small