699 FXUS66 KLOX 040541 AFDLOXArea Forecast Discussion...UPDATED National Weather Service Los Angeles/Oxnard CA 1041 PM PDT Fri Oct 3 2025
UPDATED AVIATION SECTION
.SYNOPSIS...03/621 PM.
An upper-level trough of low pressure will continue to exit the region through Saturday. Skies will continue to clear with gusty northerly winds expected in portions of Santa Barbara, Ventura, and Los Angeles Counties into early Saturday. Cooler than normal conditions will linger into late next week as broad troughing remains over the West. A warming trend is possible for late next week.
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.SHORT TERM (FRI-MON)...03/808 PM.
The latest water vapor imagery shows an upper-level trough of low pressure exiting the region this evening. Some light rain or night through morning drizzle was recorded overnight last night and into this morning as the trough`s dynamics moved over the region. Clouds are clearing this evening and any low clouds should rather broken up. The best chances for any low clouds will be for the immediate Central Coast, southern Los Angeles County, the interior portions of San Luis Obispo, and the interior slopes of the mountains. The developing northerly gradient and cold air advection will continue to scour out the low clouds and weaken the marine inversion making for a less chance of clouds across the coastal and valley areas.
The tightening northerly gradient will bring an increase in northerly winds across southern Santa Barbara County and through the Interstate 5 Corridor. The winds at Gaviota Hills RAWS are already hitting advisory criteria this evening as the KSBA-KSMX tightened to around -4.5 mb earlier. Northerly winds should start to develop through Interstate 5 Corridor as NAM-WRF boundary layer and 850 mb winds increase, while 850 mb thermal gradients tighten to near 6 degrees Celsius over the Interstate 5 Corridor. A wind advisory is in effect until 5 am Saturday for southern Santa Barbara County, through the Interstate 5 Corridor, and down into the far western portion of the Antelope Valley.
As the trough vacates, a slight amount of warming will develop through the weekend, but temperatures will largely remain on the cool side of normal through the weekend.
***From Previous Discussion***
With the upper low moving into the Great Basin Saturday onshore flow reverses to a light offshore push in the morning and forecast soundings indicate much drier conditions in the boundary layer. This should lead to a sunny start to the day in most areas and at least 3-6 degrees of warming. Models continue to show another shot of northerly winds Saturday evening but not as strong or widespread as today. Sunday will be similar to Saturday in most areas with a slight warning trend, mainly inland areas. Highs will still be a few degrees below normal in most areas.
A few degrees of cooling expected Monday as the next upper low dropping out of Canada carves a trough across the Great Basin and California. May start to see a return of marine layer stratus by that time, but otherwise minimal impacts locally.
.LONG TERM (TUE-FRI)...03/154 PM.
The trough will remain in place into next weekend keeping temperatures cooler than normal, and likely with a steady dose of marine layer stratus that may reach the valleys, but otherwise very low impact weather across the area at least through Thursday.
The forecast gets significantly more complicated at the end of next week as that trough continues to deepen along the West Coast, while at the same time some of model solutions are showing another tropical system moving up the coast from Mexico. A few of those solutions actually bring some rain to southern California as early as next Friday. It will likely take well into next week to get some clarity on this pattern but for now there are some slight chances for rain in the forecast late next week.
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.AVIATION...04/0540Z.
At 0526Z at KLAX, the marine layer was 800 ft deep, with a weak inversion up to around 1300 ft with a maximum temperature of 19 C.
High confidence in VFR TAFs for KSMX, KSBP, KSBA, KOXR, KCMA, KPMD, and KWJF.
Low confidence in TAF for KPRB. There is a 50% chance of MVFR cigs from 10Z through 17Z.
Moderate confidence in remaining TAFs. 10-20% chance of brief MVFR cigs developing between 10Z-17Z for LA County sites, highest at KLGB. There is a 40% chance no north winds impact KVNY tonight, and a 20% chance they do surface at KBUR through 10Z.
KLAX...Moderate confidence in TAF. There is a 15% chance of BKN008-BKN018 cigs from 12Z-17Z Sat. Between 08Z and 17Z, there is a 30% chance of an east wind component reaching 8 kts.
KBUR...Moderate confidence in TAF. 20% chance for north winds up to 10 kts through 10Z. There is a 10% chance of BKN010-BKN025 cigs from 10Z-17Z.
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.MARINE...03/804 PM.
A Gale Warning is in effect for the waters around Point Conception and south to San Nicolas Island as well as across the entirety of the Santa Barbara Channel through late tonight. Small Craft Advisory (SCA) level winds will linger following Gale force winds for the outer waters and portions of the inner waters thru Saturday night. After Saturday night, conditions generally look to remain below SCA criteria through mid-week.
For the waters adjacent to Los Angeles and Orange counties, moderate confidence in widespread SCA seas and NW to W winds through this evening, including nearshore (specifically Long Beach & northward). Thereafter, conditions generally look to remain below SCA criteria through mid-week.
Seas will be large and very choppy through late tonight, peaking between 8 and 12 feet for the Outer Waters and nearshore Central Coast waters, and 5 to 8 feet for the inner waters south of Point Conception, highest in the Santa Barbara Channel. Seas may reach 10 feet in the southern portion of the Santa Barbara Channel.
These strong NW to W winds and large, choppy seas will create dangerous boating conditions for many of the nearshore waters around the islands and at the coasts. These conditions will be especially dangerous for small vessels. Remain in safe harbor through tonight until conditions improve.
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.LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory remains in effect until 5 AM PDT Saturday for zones 349-351-352-378-381-383. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 3 AM PDT Saturday for zone 645. (See LAXMWWLOX). Gale Warning in effect until 3 AM PDT Saturday for zones 650-673-676. (See LAXMWWLOX). Small Craft Advisory in effect until 11 PM PDT this evening for zone 655. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Sunday for zone 670. (See LAXMWWLOX).
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PUBLIC...Hall/MW AVIATION...Lewis MARINE...Black/Schoenfeld SYNOPSIS...Hall
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox
NWS LOX Office Area Forecast Discussion