


Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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516 FXUS66 KLOX 102103 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 203 PM PDT Thu Jul 10 2025 .SYNOPSIS...10/1250 PM. Above normal temperatures will linger into the weekend, but a cooling trend will establish into early next week. The best cooling will occur across the coast and valleys. Night through morning low clouds and fog will become a staple of the forecast, expanding in coverage over the weekend. Monsoon moisture could spread into the region during the middle to later half of next week. && .SHORT TERM (TDY-SUN)...10/152 PM. Another hot day is occurring across the valleys, mountains, and desert as strong high pressure aloft remains in place today. Several sites away from the coast are closing in on the 100 degree mark in the Southland. A heat advisory (issued earlier this morning) remains in effect until 8 pm PDT this evening due to air mass approaching critically hot criteria for people sensitive to the heat. Onshore flow, keeping temperatures moderated along the coast the past several days, will strengthen through early next week. The marine layer depth will deepen over the coming days and through the weekend as strong onshore flow establishes. With 500 mb heights not changing by much and model solutions continuing to suggest KLAX-KDAG surface pressure gradients exceeding 9 mb, there is some concern that low clouds and fog may sock in the beaches similar to a May Gray or June Gloom day. Outside the marine layer depth, the air mass will remain and above normal for this time of year. The latest NAM BUFR time height sections suggest the marine layer depth deepening to near 1500 feet deep at KLAX by Saturday, so it is same to assume the foothills, mountains and desert will remain above seasonal normals. Despite strong onshore flow exceeding 5 to 6 mb along the Central Coast, dense fog issues should linger over the next several nights and mornings. With the strong onshore flow developing and surface pressure gradient above the 97th percentile for this time of year, gusty onshore winds are likely to develop across the interior valleys, such as the San Luis Obispo County interior valleys and the Antelope Valley. While confidence higher for advisory level winds each afternoon and evening in the adjacent foothills of the Antelope Valley, advisory level winds cannot be ruled out in the Shandon and Cholame Valleys and the Antelope Valley floor. Wind advisory headlines could be needed as soon as Friday afternoon and evening, but there is always some uncertainty with the actual surface pressure gradient values as the transition takes place. Confidence is a bit higher for stronger gradient values over the weekend as the onshore flow will likely strengthen into the forecast range. With the gusty winds across the interior and warmer than normal conditions lingering, elevated to brief critical fire weather conditions are likely to persist. .LONG TERM (MON-THU)...10/201 PM. Strong onshore flow will remain in place through at least Monday, and possibly into Tuesday. EPS solutions suggest a brief pop-up in the 500 mb heights on Sunday, which will likely thin the marine layer slightly, but strong onshore flow in place will likely drive the forecast for most coastal and valley areas. Night through morning low clouds and fog will continue to be a staple of the forecast, struggling to clear from the beaches and immediate coast each afternoon. Gusty onshore winds will continue to flirt with advisory levels across the interior portions of the area. Currently, the latest forecast ensembles suggest a weakening of the onshore flow pattern on Wednesday, then hint at the possibilty of the window opening up for monsoonal moisture to slip into the region. && .AVIATION...10/1805Z. At 1730Z, there was a 700 foot marine layer at KLAX. The top of the inversion was near 3900 feet with a max temperature of 27 C. High confidence in VFR TAF for KPMD, KWJF, KBUR, and KVNY. Lower confidence in winds for KVNY, where there is a 40% chance of a W wind 8-12 kts surfacing from 22Z to 04Z. High confidence in return of cigs at KSMX tonight and moderate confidence in KSBP (+/- 2 hours timing). Moderate confidence in vsbys. There is a chance for less than 1/2SM at KSBP (20%) and KSMX (30%). Low confidence in remaining TAFs. There is a 40% chance for brief cigs 004-010 at KLAX and KSMO through 21Z, but low confidence in minimum cig height and there is a 15% chance VFR conds prevail through the period after that. There is a 30% chance for IFR cigs after 08Z at KCMA (30%) and KSBA (20%). For KOXR there is a 30% chance for no cigs. If cigs arrive, timing may be off +/- 3 hours and minimum flight cat may be off by one cat. KLAX...Moderate confidence in TAF. A patch of low clouds developed off the west coast of the LA Basin. There is a 40% chance for brief cigs 004-010 through 21Z, but low confidence in minimum cig height. Vsbys may be as low as 1SM if clouds make it to KLAX. For tonight, arrival of low clouds may be off +/- 3 hours and minimum cig height may be off +/- 400 feet. There is a 15% chance for VFR conds to prevail tonight. Moderate confidence in any east wind component remaining under 8 kts. KBUR...High confidence in VFR TAF. && .MARINE...10/133 PM. Small Craft Advisory (SCA) level winds will continue across the outer waters south of Point Conception through late tonight and into early Friday morning. Local Gale Force wind gust are possible through this evening from Point Conception south to San Nicolas Island. SCA level winds will continue across the inner waters north of Point Sal and the Santa Barbara Channel this afternoon and evening. Local gusts to 21 kts may occur nearshore along the Ventura coast and off the coast of Los Angeles and Orange Counties, particularly across the San Pedro Channel and near Point Dume through this evening. Steep and choppy seas are likely across most of the inner waters through late tonight. Patchy dense fog focused across the waters adjacent to the central coast and west of the Channel Island will likely occur tonight and into morning hours tomorrow. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Heat Advisory in effect until 8 PM PDT this evening for zones 88-342>345-369>372-374-375-379-380. (See LAXNPWLOX). Wind Advisory remains in effect until 3 AM PDT Friday for zones 349-351. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 9 PM PDT this evening for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Friday for zones 650-670. (See LAXMWWLOX). Small Craft Advisory in effect until 9 AM PDT Friday for zones 673-676. (See LAXMWWLOX). && $$ PUBLIC...Hall AVIATION...Lewis MARINE...Lewis SYNOPSIS...Hall weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox