Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
151 FXUS66 KSGX 072041 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 141 PM PDT Sun Jul 7 2024 .SYNOPSIS... Slightly cooler west of the mountains through Monday, with heat continuing in the deserts. Temperatures climb region-wide Tuesday and little day-to-day change is expected through Thursday. Increasing moisture by late week will lead to slight chances of monsoonal showers and thunderstorms. The marine layer will maintain its presence near the coast and far western valleys, with clouds in the evenings and patchy fog each morning. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... A 597 DM high is centered over California today, promoting widespread dangerous heat across most of the western United States. Skies have cleared out almost everywhere, with a few patches persisting across some beach communities. Temperatures are running slightly cooler than yesterday afternoon, likely due to higher dew points across the valleys and deserts. It will still be a hot day with highs ranging 3-8 degrees above normal and up to 12 degrees above in the High Desert. This will continue the moderate to locally high heat risk across the aforementioned areas today, and locally extreme heat risk in the deserts, even if the highs aren`t quite as hot as Saturday. Continue to take precautions to protect yourself and loved ones against heat illnesses. The ridge axis moves eastward early this week and positive height anomalies weaken, promoting slight cooling west of the mountains, but a few degrees of warming in the deserts. The ridge strengthens again by Tuesday, leading to a noticeable uptick in temperatures. Highs look to remain relatively unchanged each day Tuesday through Thursday. Forecast Highs Tuesday-Thursday: Coast: upper-70s to low-80s. Inland Orange/San Diego County Valleys: mid-80s to mid-90s, approaching 100 degrees along the foothills in San Diego County. Inland Empire: upper-90s to 108. Mountains: upper-80s to upper-90s. High Desert: 105-110. Lower Deserts: 112-120. The ridge axis slowly progresses eastward towards the Four Corners region by Thursday and Friday, allowing an increase in low and mid-level moisture as winds shift to the south-southeast. GEFS/EPS PWAT ensemble trends peak over the weekend, leading to the most favorable time to see any monsoonal activity. This will promote cooler temperatures to near normal values, but with muggier conditions, especially in the deserts. NBM storm probabilities peak on Saturday and Sunday with a 10 to 20 percent chance for higher terrain into the deserts. && .AVIATION... 072010Z...Coast/Valleys...Mostly clear for most locations, with isolated patches of clouds remaining along/near beaches through the afternoon. More low clouds with similar bases, generally 700-1000 FT MSL, moving back onshore after 02Z-03Z Mon. There is a 40% chance of CIGs at KONT overnight, most likely timing appears to be 11-15z Mon. VIS below 1 SM where low clouds and terrain intersect. Scatter out expected 16-18z Mon. Mountains/Deserts...Mostly clear skies with unrestricted VIS through Monday. West winds increasing after 19z, with peak gusts of 25-35kts occurring over and east of the mountains. Weak to moderate up/downdrafts over and east of the mountains as well. && .MARINE... No hazardous marine conditions are expected through Thursday. && .BEACHES... A long-period south swell will continue to create elevated surf even as it gradually subsides through today. Sets up to 6 feet can be expected on south and southwest-facing beaches, especially in Orange County. Risks for rip currents will remain elevated as well. Check the Beach Hazards Statement for details. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Beach Hazards Statement until 5 PM PDT this afternoon for Orange County Coastal Areas-San Diego County Coastal Areas. Excessive Heat Warning until 9 PM PDT this evening for Riverside County Mountains-San Bernardino County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire- San Diego County Mountains. Excessive Heat Warning until 9 PM PDT Thursday for Apple and Lucerne Valleys-Coachella Valley-San Diego County Deserts- San Gorgonio Pass Near Banning. PZ...None. && $$ PUBLIC...EA AVIATION/MARINE...Adams