860 FXUS66 KLOX 121513 AFDLOXArea Forecast Discussion National Weather Service Los Angeles/Oxnard CA 813 AM PDT Sun Oct 12 2025
.SYNOPSIS...12/329 AM.
Gusty northeast will weaken through today with mostly clear skies expected today. A winter like storm system will move across the area late Monday through Wednesday, with most of the rainfall likely Monday night through Tuesday afternoon. Expect widespread light to moderate rain with potential for locally heavy showers and thunderstorms, and gusty southerly winds.
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.SHORT TERM (TDY-TUE)...12/812 AM.
***UPDATE***
Latest satellite and surface observations clear skies across the area except for some patchy stratus/fog across the LAX coastal plain and Catalina Island. Current sounding data indicates marine inversion around 600 feet deep. As for winds, north to northeast winds, gusting 25-40 MPH, are currently observed.
Forecast-wise for the immediate short term, no significant issues are expected. Offshore winds will likely bump up a bit around sunrise, but should begin the downward trend by late morning. So, will let current slate of WIND ADVISORIES continue until 1000 AM then likely let it expire. As for stratus/fog, they should dissipate by late morning with sunny skies for all areas this afternoon. As for temperatures, most areas should be a few degrees warmer than Saturday, but expect little change along the coast.
Overall, current forecast has good handle on the immediate short term. So, other than the likely expiration of the WIND ADVISORIES at 1000 AM, no updates are anticipated. For the afternoon forecast suite, attention will be focus on Monday night through Tuesday night storm.
***From Previous Discussion***
This morning, as yesterday`s trough travels to the east, surface pressure gradients that were predominantly north- to-south will take on a slight east-to-west offshore component. This will result in north to northeast winds through this morning. Gusts of 35-45 mph will be common for the Santa Babara South Coast, the I-5 corridor, the Santa Clarita Valley, and favored mountains and foothills. WIND ADVISORIES remain in effect for these areas until mid-morning, though they may be canceled earlier based on observations.
Monday an unseasonably strong low pressure system will travel south along the west coast, cutting east across California just south of the Bay Area late Tuesday. Widespread rain is expected, with around 5 to 10 hours of light to moderate rain occuring between Monday night and Tuesday afternoon, and scattered showers thereafter. Rain will start as early as Monday afternoon for San Luis Obispo County, reaching Santa Barbara County late in the evening Monday, Ventura County by midnight, and Los Angeles County early Tuesday morning. For San Luis Obispo and Santa Barbara Counties, storm total rain is forecasted to be 1.5 to 2.5 inches for the lowlands and 2.0 to 4.0 inches for foothills and mountains. Latest high resolution forecast models have trended upwards for Ventura and Los Angeles Counties, especially the orographically enhanced rainfall component. Totals for LA/Ventura Counties are forecasted to be 0.75 to 1.25 inches for the lowlands (except 0.25 to 1.0 inches for the Antelope Valley) and 2.0 to 3.5 inches for the San Gabriel Mountains and foothills.
Weather models are now in rather good agreement for the path of the storm, thus allowing the range of possibilities and impacts to converge. The source of most uncertainty at this point lies with the convective potential. This system is very dynamic with parameters that indicate there is a chance for a line of strong storms to develop as the cold front passes (Monday night through Tuesday afternoon), some of which may be rotating. This would result in higher rain rates (up to around 0.8 inches/hour possible) embedded within the widespread light to moderate rain, as well as small hail, brief damaging winds, lighting, and a remote chance of a waterspout or weak tornado. Overall thunderstorm chances are around 25-35% for San Luis Obispo and Santa Barbara Counties, and 15-25% Ventura and Los Angeles Counties. Latest high resolution models indicate increased chances for thunderstorms across much of Los Angeles County. There is a small risk of local areas of flash flooding and debris flow issues (especially for recent burn scars). Overall, the most common impacts are likely to include travel delays due to slick roads, ponding of water, and canceled outdoor events.
Winds will also accompany this event, thanks to a vigorous jet associated with the trough and cold air advection. South to southwesterly winds are expected across the area late Monday through Tuesday afternoon. The strongest winds will likely be ahead of the frontal passage, preceding the main core of the rainfall, though strong winds are also possible during the heaviest rain especially with rotating thunderstorms. Widespread Wind Advisories are likely, with a chance for local High Wind Warnings.
Snow levels are likely to fall to 6000-7000 feet Tuesday, thus some (few inches) accumulations are possible at resort levels. Additionally, during a convective storm cell, locally lower snow level may drop snow levels briefly even lower. There is however a high amount of uncertainty with this element of the forecast.
.LONG TERM (WED-SAT)...12/341 AM.
As the low exits the region Wednesay, no precipitation is expected but the troughing pattern will persist. Temperatures will again be cool, only slightly warmer than Tuesday (60-70 degrees common) with mostly clear skies as the marine layer will remain disturbed. Thursday through the weekend, dry conditions and a warming trend are likely with a chance for offshore flow. The next chance for any precipitation appears to be early next week (Oct 20-21), though at this point only a handful of ensemble members favor any rain.
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.AVIATION...12/1303Z.
At 1227Z at KLAX, the marine layer was 600 ft deep. The top of the inversion was at 1100 ft with a temperature of 17 C.
Overall, good confidence in 12Z TAF Package.
Generally expecting VFR conditions through the period. The exception is at KLGB, KSMO, & KLAX where LIFR conditions are possible at times through 17Z Sun, and MVFR CIGs are possible towards end of fcst period.
Moderate confidence in wind forecasts.
KLAX...Moderate confidence in 12Z TAF. Through 17Z Sunday, expect fluctuations between FEW/SCT 003-005 & BKN/OVC 003-005. Highest chance for persistent LIFR CIGs likely to fall between 14Z to 16Z Sun. Good confidence in clearing by 17Z (+/- 1 hr). MVFR Cigs ~015 likely (60%) to arrive sometime after 08Z Mon. There is a 60-70% chance of east wind component reaching 7-8 knots from 08Z Mon thru 18Z Mon.
KBUR...High confidence in 12Z TAF. VFR conditions expected thru forecast period.
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.MARINE...12/738 AM.
For the outer waters southwest through northwest of the Channel Islands, including the nearshore waters along the Central Coast, winds have subsided below GALE force across the northern waters and thus the GALE Warning has been replaced with a Small Craft Advisory (SCA) (PZZ670/645). Winds will remain strong from Point Conception south to San Nicolas Island, thus GALE Warning remains in effect across this area through late tonight (PZZ673/676). SCA conditions are likely to linger in some fashion through Monday morning.
For the inner waters south of Point Conception, winds are expected to increase to SCA levels this afternoon across western & southern portions of the Santa Barbara Channel. Likely reaching the Anacapa Passage by early evening. Good confidence that winds calm to below SCA levels by early Monday morning.
Monday evening through Tuesday night, a storm system and associated cold front will move across the region. This will bring a 20-40% chance of thunderstorms to the Santa Barbara Channel, west past the Channel Islands, and northward to the San Luis Obispo County Line. For the waters south of the Santa Barbara Channel, including the waters nearshore LA and Orange Counties, there is a 10-20% chance of thunderstorms.
Any thunderstorm that forms may be capable of frequent cloud to surface lightning, gusty and erratic winds, small hail, and even a waterspout. Additionally, widespread SCA level SW winds and seas, with a moderate chance of GALES between Monday night and Tuesday night due to the aforementioned storm.
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.LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory remains in effect until 10 AM PDT this morning for zones 88-352-353-375>379. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 9 AM PDT Monday for zones 645-670. (See LAXMWWLOX). Small Craft Advisory in effect from 3 PM this afternoon to 3 AM PDT Monday for zone 650. (See LAXMWWLOX). Gale Warning in effect until 3 AM PDT Monday for zones 673-676. (See LAXMWWLOX).
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PUBLIC...Schoenfeld/Thompson AVIATION...Black MARINE...Black/Lund SYNOPSIS...Schoenfeld
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox
NWS LOX Office Area Forecast Discussion