602 FXUS66 KLOX 270942 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 242 AM PDT Sun Jul 27 2025 .SYNOPSIS...27/226 AM. An upper-level trough anchored along the West Coast will keep a persistent onshore flow pattern in place through Tuesday. Night through morning low clouds and fog will remain in the forecast for most coastal and valley locations. A slow warming trend will take shape through the week, especially outside the marine layer depth as high pressure aloft over the southeastern United States meanders west. Closer to the coast, onshore flow will keep the warming trend moderated with temperatures remaining below normal through much of the week. && .SHORT TERM (TDY-TUE)...27/224 AM. The latest water vapor imagery shows an upper-level trough anchored over the West Coast this morning with a broad upper-level ridge of high pressure over the southeastern United States. A few high clouds are developing over the area this morning as a vort max with the weak trough is moving over the region. Fog product imagery indicates low clouds and fog well-entrenched along the Central Coast early this morning, while an eddy circulation over the southern California is a little slower to regenerate. With the vorticity maximum moving over the region, drizzle cannot be ruled out across the coastal and valley areas this morning, but if the eddy circulation begins to push clouds back into the Southland, this portion of the area would be in a little more favorable areas for drizzle to develop. Low clouds and fog will remain a staple of the forecast for the next several nights and mornings across most coastal and valley areas, but 500 mb heights will climb over the next several days. This will very likely thin the marine layer depth through the short term period. The troughto the northwest of the area will serve to keep the marine influence and strong onshore flow in place. A pattern reminiscent of June will set up with a strong onshore push and a tight marine inversion developing. Clouds will likely struggle to clear from the land mass each day, especially along the Central Coast where the region is much closer to the trough`s influence. EPS ensemble cloud cover means indicate minimal clearing each day at K87Q, KVBG, and KLPC, and clouds should be expected to hug the Central Coast each day. Outside of the marine influence in the higher valleys, foothills, mountains, and desert, a gradual warming trend will develop with a few degrees of warming each day. Temperatures will inch closer to normal by Tuesday across the interior portions of the area, but within the marine intrusion, a cooler than normal air mass will likely remain. The warming trend will be much more muted along the coast and at the beaches. A northwesterly surface gradient will keep enhanced diurnal winds across southern Santa Barbara County for the next several nights, but gusty Sundowner winds are not expected through the short- term period at this time. .LONG TERM (WED-SAT)...27/226 AM. The northwest surface gradient will tighten a bit more on Wednesday as a weak upper-level trough moves over central California. A much cooler air mass to the northwest of the area and a warmer air mass remaining over southeastern California will likely set up a tighter northwesterly gradient across the region. KSBA-KSMX surface pressure gradients tighten for Wednesday evening and this could be the first evening of advisory level Sundowner winds. EPS ensemble members suggest some cooling taking place along the coast and valley areas as 500 mb heights decline between Wednesday and Thursday. Onshore flow is likely to increase across the region and some deepening of the marine layer seems plausible between Wednesday and Thursday. After Thursday, 500 mb heights will start to climb again and bring additional warming away from the coast and into the interior portions of the area. These areas will likely pop above normal for late week with temperatures possibly closing in on the 100 degrees out in the Antelope Valley on Friday. Despite the rising heights, cluster analysis reveals the persist trough remaining over the West Coast. This will likely keep onshore flow in place and keep night through morning low clouds and fog a staple of the forecast for most coastal and valley areas. && .AVIATION...27/0543Z. At 0454Z at KLAX, the marine layer was around 1200 ft deep. The top of the inversion was around 3000 feet with a max temperature of 19 C. High confidence in VFR TAFs for KWJF and KPMD. Low confidence in TAF for KSBA, where there is a 40% chance for VFR conds to prevail. If cigs arrive, minimum cig height may be off +/- 500 feet and timing may be off by 2 hours. Moderate confidence in remaining TAFs. High confidence in cigs arriving at all sites, except moderate confidence for KPRB, KCMA, and KBUR, KVNY. For the previous sites, there is a 10-20% chance VFR conds prevail. Timing of flight cat change may be off by +/- 2 hours. Moderate confidence in minimum cig height (+/- 300 feet). KLAX...Moderate confidence in TAF. High confidence in winds, moderate confidence in timing of flight category changes (cigs may arrive tonight as early as 07Z and as late as 10Z Sun) and cig heights may be off by +/- 300 ft, but are likely to remain between OVC010-OVC020 from 07Z-17Z. Timing of dissipation may be off by +/- 90 minutes). No significant east wind component expected. KBUR...Cigs may arrive tonight as early as 09Z and as late as 13Z Sun) and cig heights may be off by +/- 300 ft, but are likely to remain between OVC010-OVC020. There is a 15% chance of no cigs developing tonight. && .MARINE...27/237 AM. High confidence in unseasonably small (but choppy) seas into Monday morning, then seas are likely to build to 6-8 feet across the Outer Waters Monday evening through the period. Moderate confidence in Small Craft Advisory (SCA) winds from Point Sal to San Nicolas Island (with local SCA level gusts in the northern Outer Waters) this afternoon and evening, becoming more likely Monday afternoon through evening and expanding northward through at least Thursday. The western portion of the Santa Barbara Channel will reach SCA during the evenings though at least Wednesday, with a moderate chance for winds to become widespread enough to warrant Small Craft Advisories through Monday, then higher chances Tuesday and Wednesday. For Wednesday night, there is a a 30% chance of low- end Gales for the waters beyond 20 miles from shore, with best chances from around Point Conception south to San Nicolas Island. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...Small Craft Advisory in effect until 3 AM PDT early this morning for zones 650-673-676. (See LAXMWWLOX). Small Craft Advisory in effect from 3 PM this afternoon to midnight PDT tonight for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect from 3 PM this afternoon to 3 AM PDT Monday for zone 673. (See LAXMWWLOX). Small Craft Advisory in effect from 6 PM this evening to 3 AM PDT Monday for zone 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