760 FXUS66 KLOX 260603 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 1103 PM PDT Fri Jul 25 2025 Updated Aviation Section .SYNOPSIS...25/715 PM. A persistent onshore flow pattern will continue into early next week as an upper-level trough remains anchored to the north of the area. Night through morning low clouds and fog will continue to be a staple of the forecast for most coastal and valley locations through Monday. Late night and early morning drizzle cannot be ruled out, especially Saturday morning. Below normal temperatures will linger through the weekend, then a warming trend will establish as onshore flow weakens. && .SHORT TERM (FRI-MON)...25/808 PM. The latest water vapor imagery shows an upper-level trough of low pressure over the state this evening. The trough, centered near Modesto, will slowly lift out to the northeast through the weekend while dampening. The trough will serve to keep a persistent and strong onshore flow in place that will feed a deeper marine layer depth. The latest RAOB sounding from KVBG indicates a 2400 foot deep marine layer depth north of Point Conception, sloping to about 1100 feet deep south of Point Conception at KLAX. The latest NAM BUFR time height sections indicate the marine layer depth deepening some overnight, especially south of Point Conception as an eddy circulation regenerates. Low clouds and fog will push well into the valleys tonight and into Saturday, likely reaching some of the coastal slopes by Saturday morning. The deepening marine layer depth will interact with the upper-level dynamics with the trough overnight tonight and into Saturday morning to squeeze out some drizzle. Late night through early morning drizzle cannot be ruled out across many coastal and valley locations, but the most favorable chances for heavy drizzle or light rain will likely occur for areas north of Point Conception. NAM BUFR time height sections indicate a few hundredth of precipitation for KSBP and KSMX late tonight and early Saturday morning, while multi-model high resolution ensemble members favor a slight probability of precipitation along the Central Coast. PoPs were increased above the previous and current NBM values and a mention of drizzle was added to the forecast overnight and Saturday morning. A cooler than normal weather pattern is likely to persist through the weekend with persistence being the best forecast, especially along the beaches and immediate coastal locales. Temperatures well below seasonal normals will linger through the weekend and into early next week. A tighter northwesterly surface pressure gradient across Santa Barbara County will continue, but Sundowner winds should be weaker than last night across the southwestern portion. KSBA-KSMX surface pressure gradients were running a little stronger than this time last night an hour ago but have since backed off. The latest model solutions and ensemble member gradients suggest the pattern weakening through the night. At this point, the best approach is to monitor surface pressure gradients and wind observations for further development. ***From Previous Discussion*** Overall, forecast guidance is in good synoptic agreement through the short term period. The upper-level pattern features a low over Central California that is expected to weaken Saturday. As the ridge over the eastern CONUS retrogrades/builds, the H5 flow will become more cyclonic over our area. Therefore, moderate onshore gradients will persist, meanwhile northerly offshore gradients will weaken. Forecast-wise, fairly benign weather with cooler than normal temperatures expected through the weekend. Concerning the Marine Layer, it is expected to deepen a few hundred feet overnight and will likely reach the Santa Clarita Valley. Patchy drizzle is likely. Thereafter, H5 heights will begin to increase, compressing the MABL (marine atmospheric boundary layer) and reducing coverage and extent inland. Elsewhere, skies are expected to remain mostly clear other than some high clouds. Sundowners are expected to remain sub-advisory and confined to the western half of the Santa Ynez Range, with a gradual decrease in wind speeds through the weekend. The Antelope Valley and adjacent foothills will have gusty winds each afternoon and evening but will remain sub-advisory. Overall, no wind issues are expected. Below normal temperatures with minor day-to-day temperatures fluctuations are expected through Saturday. Due to an increase in H5 heights and less MABL influence, expect a few degrees of warming each day through Monday. .LONG TERM (TUE-FRI)...25/223 PM. High confidence in calm and warmer weather in the long term, with few impacts for the general public. A warm up is expected, however daytime highs are not favored to exceed normal by more than a few degrees. There is little-to-no risk for extreme heat through at least next Saturday (August 2). Forecast models are in agreement that 500 mb heights will gradually trend upwards into late next week, as high pressure over the southern central US affects the region. However, a strong low pressure system off the coast of British Columbia and associated shortwave troughs, will dampen the westward extend of the ridge into SoCal. Thus temperatures Tuesday through Friday will be warmer than this week, but will remain near normal for much the region. Near the surface, moderate onshore gradients will continue to the east, with weak northerly offshore gradients. This will maintain cooling sea breezes, overnight to morning clouds for the coasts and some valleys (although inland extend will become less extensive). Sundowner winds across southwest Santa Barbara County and southwest onshore breezes for the interior (especially the Antelope Valley and foothills) will continue to be common in the afternoons and evenings. && .AVIATION...26/0551Z. At 05Z at KLAX, the marine layer was 1200 ft deep. The top of the inversion was 3200 feet with a temperature of 18 Celsius. High confidence in VFR TAFs for KWJF and KPMD with seasonably gusty southwest winds. Moderate confidence in persistence (similar to previous 24 hours) ceiling timing (+/- 2 hours) and heights (+/- 300 feet). MVFR categories prevalent. Some sites that did not get ceilings last night have a 30% chance of getting clouds tonight including KSBA KBUR KVNY. KLAX...High confidence in wind forecast, moderate confidence in ceiling formation and flight categories (MVFR), low confidence on timing. Moderate confidence in 18Z TAF. High confidence in any southeast winds staying below 8 knots. KBUR...30% chance of MVFR ceilings forming for 1-3 hours in the 12-16Z time window. && .MARINE...25/757 PM. For the Outer Waters, SCA winds are expected south of Point Sal through Saturday, with a 30% chance of SCA level winds north of Point Sal. Areas of SCA winds across the outer waters will continue through as least Tuesday and likely through Wednesday. For the Inner Waters north of Point Sal, there is a 30-40% chance of SCA level winds in the afternoon and evening hours each day except for a 40-50% chance Sunday afternoon and evening. For the Inner Waters south of Point Conception, Small Craft Advisory (SCA) level winds are expected across the western half of the Santa Barbara Channel during the late afternoon and evening hours, with a 20% chance of SCA level wind elsewhere across the Southern Inner Waters. Winds will likely remain below SCA level Monday and Tuesday except for a 30% across the Western Santa Barbara Channel. Winds are then expected to increase Wednesday with a 30-50% chance of SCA speeds Wednesday afternoon through Wednesday night. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...Small Craft Advisory in effect until 3 AM PDT Saturday for zones 650-673-676. (See LAXMWWLOX). && $$ PUBLIC...Hall/Black AVIATION...Kittell MARINE...Black/Schoenfeld/Ciliberti SYNOPSIS...Hall weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox