Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
158 FXUS66 KSGX 140330 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 830 PM PDT Tue Aug 13 2024 .SYNOPSIS... Fair and seasonal weather will continue through the weekend. Areas of coastal low clouds will continue nights and mornings, extending into western valleys. Temperatures will remain around normal, followed by a warming trend next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .Evening Update... Ribbons of low clouds are beginning to form over the sea and near some of our beaches this evening. Latest NBM/HRRR model output depicts increasing coverage of these clouds, mainly after midnight. Dry conditions will prevail through at least Friday as drier air has come into the picture. Precipitable water levels have gone down from 1.30 inches to 0.80 inches, when comparing yesterday and today`s upper air soundings from Miramar in San Diego. There will be minimal changes in temperatures from day to day through the weekend as we stay sandwiched in between a trough to the north and west and a ridge to the south and east. The ridge looks to slowly nudge back westward by the weekend, which may prompt more monsoonal activity. Some ensemble models show hints of this occurring. Otherwise, no forecast changes this evening. .Previous Discussion (134 PM Tuesday)... Coastal low clouds and fog have fled, but will eventually have very similar coverage tonight into Wednesday as they did this morning. But coastal low clouds should not be as prevalent or uniform for early Thursday. What you see now is what you get: lots of sunshine. Gusty westerly winds will blow through parts of the mountains and deserts through tonight. Top gusts in the windiest places, the usual spots through passes into adjacent deserts, will exceed 40 mph. A weaker version of these westerly winds will manifest itself late Wednesday. Temperatures will be within a few degrees of normal through the rest of the week, with only minor variations day to day. Very slightly warmer Thursday, slightly cooler Friday and Saturday. A weak trough of low pressure over the Pacific Northwest will continue to press against a stubborn high pressure ridge over Texas for what looks like forever. This weekend, a trickle of monsoonal moisture begins to flow into SoCal. For several days, the moisture is insufficient for thunderstorms through at least the weekend, but eventually there might be enough moisture and instability for storms in the mountains and deserts by Tuesday or Wednesday. Early next week, the ridge imposes itself just a little more to bring a modest warming trend. && .AVIATION... 140330Z...Coast/Valleys...Low clouds with bases 700-1000 feet MSL and tops to 1200 feet beginning to gather at the coast this hour. Low clouds will increase in coverage and spread up to 10 miles inland by 14Z. 40-60 percent chance of CIGs at KSAN and KCRQ at 09Z becoming 60-80 percent by 14Z. About a 30 percent chance for CIGs at KSNA at 09Z becoming about 75 percent by 14Z. Local VIS 3-5 miles on higher coastal terrain. Expect clearing to the beaches 15Z-16Z. Mountains/Deserts...Mostly clear with unrestricted VIS through Wednesday morning. && .MARINE... No hazardous marine conditions are expected through Sunday. && .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...APR/MM AVIATION/MARINE...PG