Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
051 FXUS66 KSGX 222100 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 100 PM PST Fri Nov 22 2024 .SYNOPSIS... Warm and dry weather prevails today with generally clear skies and mostly light winds. An atmospheric river currently over Northern California shifts southward on Saturday, increasing moisture and cooling temperatures. Very light precipitation is expected as early as Saturday night/Sunday morning, with slightly better chances for rain Monday through Wednesday. Any rain will move out by late Wednesday, with warmer and drier conditions returning for the end of next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Warm weather and sunny skies prevail this afternoon and early evening before a deepening and more widespread marine layer develops tonight. While cloud bases will be slightly higher than the previous night, inland spread will be up to 10 miles before clearing occurs late Saturday morning. As the marine clouds clear out, a surge of moisture and clouds will move southward into Southern California ahead of a weakening atmospheric river which has been slamming much of the West Coast the past several days. By the time the AR pushes down on Saturday, the moisture and energy within this system will begin to lessen, and only meager rainfall is expected for the weekend. Areas further north, including some of the mountains, will be the big winners with this next event, seeing up to 0.50" of rainfall between Saturday and Sunday, and locally higher amounts up to 0.75". Snow levels will remain high through the weekend, primarily above 7000-7500ft, limiting what precipitation may be seen as snow. The 10th percentile NBM puts a bullseye over the San Bernardino Mountains with rain totals nearing an inch Saturday night into Sunday morning. While rain will exist outside of the mountains this weekend, only very light amounts are expected, with totals generally less than 0.10". Other than the rain, periods of strong gusts out of the west to southwest will peak around 35-40 mph for the mountain peaks and mountain passes, with some stronger gusts along the desert slopes as well. These stronger winds will be short lived, generally dissolving by early Sunday morning. The ample cloud cover and increasing moisture will cool afternoon highs this weekend and into early next week, with temperatures generally 5-10 degrees below normal. Another surge of moisture looks to arrive on Monday which may hang around through Wednesday, potentially bringing additional precipitation chances to Southern California. This next push looks better in terms of moisture amounts and energy, but models differ on exact location and how far south any rain will develop. If trends push some of the better moisture down into the area, precipitation amounts may eclipse weekend totals with the higher terrain receiving up to an inch of rain. However, if the models maintain the current look of a moisture cut off around LA county, the region may end up seeing nothing. Have gone ahead with a drier solution on the rain amounts for early next week until better alignment is observed between the global models. Regardless of how the precipitation shakes out, the cooler weather will prevail until mid week with lowering heights and cloud cover. By the end of the week, weak riding should return to the area and temperatures will slowly recover back to near normal. && .AVIATION... 222030Z...Coast/Valleys...Mostly clear skies through late this afternoon. Widespread low clouds should push ashore around 00Z-03Z Sat, bases 1000-1400 ft MSL, spreading inland 15-25 miles overnight. There is a 30% chance for CIGs at KONT 10-17Z Saturday. Clouds will scatter out 16-18Z Sat. Low clouds with higher bases and isolated, light showers of rain will then move into the region late Saturday afternoon from the northwest to the southeast as a weak weather system moves in. Mountains/Deserts...FEW-SCT clouds at or abv 20000 ft MSL and unrestricted VIS through Saturday morning. && .MARINE... No hazardous marine weather conditions expected through Wednesday. && .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...Zuber AVIATION/MARINE...CSP