Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
840 FXUS66 KSGX 150455 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 930 PM PDT Sun Jul 14 2024 .SYNOPSIS... Monsoonal moisture will bring scattered thunderstorms with locally heavy rain again over the mountains and deserts Monday, then some drying will occur Tuesday through Thursday. Monsoonal moisture could increase again late in the week and bring scattered thunderstorms again mainly this weekend. Temperatures will be near or just slightly above seasonal normals early this week, but hotter weather will return the second half of the week, possibly reaching excessive levels in some inland areas. Night and morning low clouds will continue in the coastal areas most of this week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Thunderstorms ended by a little after 6 PM in all areas with some debris clouds continuing, plus stratus along parts of the coast at mid-evening. Southerly flow aloft will continue Monday with high RH values in the thunderstorm-favorable 700-500 MB layer as well as total precip water values of around 1.4-1.5 inches at lower elevations again Monday, both west and east of the mountains. There will be a slight decrease in near-surface moisture so thunderstorms might be a little less widespread Monday, though scattered thunderstorms will still prevail. Beyond Monday, high pressure aloft will continue over the Four Corners through midweek, though shifting west gradually towards Nevada/NW Arizona and maybe SoCal the second half of the week. Southerly flow will continue, and moisture decreases rather modestly, so even though chances of thunderstorms are not currently in the forecast Tuesday through Friday, there is still a small risk of a thunderstorm, with chances increasing Friday based on the ensembles. With the upper high moving west, we could have extreme heat again over inland areas starting around Wed/Thu and continuing through the weekend, though any kinds of moisture surges from the southeast in the deserts could lower temperatures there, but heat index values may not necessarily drop. Moisture does increase around Friday, continuing over the weekend, though there are questions about if subsidence from the upper high could have an inhibiting factor. && .AVIATION... 150400Z...Coast/Valleys...Marine layer moves back in this evening with CIGs at coastal sites beginning 15/07z to 15/10z with bases 800- 1200ft MSL and tops to 1500-1800ft MSL. Scattering out will occur at a similar time to Sunday, around 15/16z-15/19z for the coast. VFR expected to prevail for the valleys with SCT-BKN100 Monday afternoon. Confidence is low for any impacts from TSRA for the valley/coastal sites on Monday. Mountains/Deserts...TSRA expected late Monday morning through Monday evening in the vicinity of the mountains with SCT-BKN100. Brief, heavy rainfall and gusty and erratic winds likely with any storm and strong up/downdrafts possible near the mountains. Confidence for impacts from TSRA to TAF sites is too low to mention at this time, but strong outflow gusts and lightning from nearby storms will be a threat through the late afternoon. Gusty west winds possible up to 35kts around San Gorgonio Pass through Monday evening. && .MARINE... No hazardous marine conditions are expected through Friday. && .BEACHES... Long period SSW swell of 3ft/18-19sec will bring elevated surf of 6- 7 feet for Orange County and San Diego County for south and southwest facing beaches with a high risk of dangerous rip currents. A Beach Hazard Statement is in effect for Tuesday morning through Thursday evening. The period will gradually decrease to around 15 seconds by Thursday. && .FIRE WEATHER... Red flag warning ended at 9 PM as thunderstorms along with the dry lightning threat have ended. While thunderstorms are expected again Monday, they will be likely be accompanied by moderate to locally heavy rainfall, even though isolated dry lightning is always a potential threat with thunderstorms. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions && .MARINE... No hazardous marine conditions are expected through Friday. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Beach Hazards Statement from Tuesday morning through Thursday evening for Orange County Coastal Areas-San Diego County Coastal Areas. PZ...None. && $$ PUBLIC/FIRE WEATHER...Maxwell AVIATION/MARINE...Zuber