


Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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012 FXUS66 KLOX 130636 AFDLOX Area Forecast Discussion...RESENT National Weather Service Los Angeles/Oxnard CA 1136 PM PDT Sun Oct 12 2025 .SYNOPSIS...12/606 PM. An early season storm system will move across the area late Monday through Tuesday, with most of the rainfall likely Monday night through Tuesday. Expect widespread light to moderate rain with potential for locally heavy showers and thunderstorms, and gusty southerly winds. && .SHORT TERM (SUN-WED)...12/857 PM. ***UPDATE*** Gusty north winds are affecting Southwest Santa Barbara County this evening, between Gaviota and Refugio. At this time gusts are just below Advisory level and models indicate winds peaking around 03Z (8 pm). So will hold off on issuing a wind advisory based on the short duration and limited area of the stronger winds. Otherwise, the forecast remains on track for a storm system approaching the area from the Pacific Northwest. An upper closed low is forecast to track southward along the West Coast tonight through Tuesday morning, and then shift eastward into the Great Basin Tuesday night. This cold and dynamic system will bring increasing south winds to much of the area, unseasonably low snow levels around 6,000 feet, rainfall totals ranging from 0.75 inch to 3.50 inches, and widespread thunderstorm chances. There is a risk of strong thunderstorms developing at times, with heavy downpours, strong gusty winds and hail. By late Tuesday night into Wednesday expect clearing and much quieter weather as the low shifts east of the area. ***From Previous Discussion*** Winds: On Monday and Tuesday, expect a dramatic increase in south to southwest winds as the upper low impacts the area. Winds will first increase across the deserts and interior sections on Monday then increase west of the mountains Monday night and Tuesday. At this time, advisory-level winds are likely across the deserts and interior sections (with a chance of warning level winds across the LA Mountains and Antelope Valley foothills). For coastal and valley areas, there is a 30-50% chance of widespread advisory level winds Monday night and Tuesday. Precipitation: All systems are still a big "GO" for the storm Monday night through Tuesday night. Based on latest guidance, expected rainfall totals have adjusted from previous thinking. Right now, coastal and valley areas can expect 0.75-1.50 inches of rainfall with 1.50 to 3.50 inches across the mountains/foothills. Of course, given the southerly flow, some favored upslope areas could receive even higher amounts. As for rainfall rates, generally will be expecting hourly rates of 0.25-0.50 inches. However, high resolution models are still indicating the potential for a QLCS-type feature on Tuesday which would generate higher rates of 0.50-1.00 inches per hour or even higher. Additionally, sub-hourly rates could be quite intense. So, given the potential for rain rates to meet/exceed USGS thresholds for the burn scars, a FLOOD WATCH will be in effect for the burn areas (see LAXFFALOX for details). There will be the potential for significant mud/debris flow issues. As for thunderstorms, the risk still remains for the area. Looking at the model solutions, the setup is looking more conducive for widespread thunderstorm potential for all areas Monday night and Tuesday. Although CAPE values are not impressive, the potential diffluent flow aloft, strong jet dynamics and low level wind shear will bring the possibility of strong thunderstorms (gusty winds, hail and heavy rain) along with waterspouts/weak tornadoes. For reference, the setup is looking similar to conditions indicated by the Hales study for Southwestern California severe weather. Finally, there still looks to be the potential for some snowfall accumulations at the higher elevations. Based on thickness and Wet Bulb Zero forecasts, snow levels look to drop into the 5500-7000 foot range on Tuesday (but locally lower with any significant convection). So, several inches of snowfall accumulation will be likely above 6000 feet. Given the strong southerly winds anticipated, Winter Storm criteria conditions could develop. Will let the next couple of shifts look at the next suite of model runs to make the final determination for any winter products. .LONG TERM (THU-SUN)...12/200 PM. For the extended, 12Z models continue to exhibit good synoptic agreement. At upper levels, ridge gradually builds over the Eastern Pacific Thursday through Saturday, before weakening on Sunday as a trough moves across Northern California/Pacific Northwest. Near the surface, weak diurnal gradients will prevail. Forecast-wise, no significant issues are expected. For Thursday through Saturday, dry conditions are expected along with a warming trend. At times, there could be some offshore winds across the area, but any winds look to be weak (if they do develop). On Sunday, as the trough rolls across the West Coast, cooler conditions are anticipated along with the possibility of some additional rainfall (but confidence in that potential remains very low). && .AVIATION...13/0615Z. At 0403Z at KLAX, the marine layer was 1500 ft deep. The top of the inversion was near 2000 ft with a temperature of 19 C. Low confidence in the 06Z TAFs for the coastal and valleys sites and high confidence in the desert sites. Expecting SHRA/RA after 00Z Tue along Central Coast with MVFR conditions and periods of low-MVFR to IFR under worst conditions. Around a 30% chance of TSRA during this timeframe for KPRB, KSBP, & KSMX. Brief LIFR conditions cannot be ruled out. In addition, there is a 10% chance of TSRA for KSBA after 03Z Tuesday. LLWS and turbulence is possible as front approaches and near any thunderstorms that develops. Low to moderate confidence in wind forecasts. Wind gusts may be off 5 to 10 knots and/or direction off by 30 degrees, especially for coast and valley sites after 00Z Tuesday - as front approaches. KLAX...Low to moderate confidence in the 06Z TAF. MVFR CIGs ~015 - 025 forecast to arrive around 09Z Mon (+/- 2 hours), with a 25% chance that no CIGs occur. There is a 70% chance of an east wind component reaching 7-8 knots from 08Z Mon thru 18Z Mon. In addition, there is a 15% chc of a thunderstorm after 10Z Tue. KBUR...High confidence in the 06Z TAF. VFR conditions expected thru forecast period, but with a 10-20% chance of MVFR CIGs during the overnight period, most likely between 10Z-16Z. 30% chance of -SHRA & MVFR CIGS ~025 after 03Z Tuesday && .MARINE...12/815 PM. Monday evening through Tuesday afternoon, a storm system and associated cold front will move across the region. This will bring a 20-40% chance of thunderstorms across all the coastal waters during that timeframe. Small Craft Advisory (SCA) level winds and seas will continue across the waters north of Point Sal (PZZ670/645) through Monday morning. Winds will remain strong from Point Conception south to San Nicolas Island, thus a GALE Warning remains in effect across this area through late tonight (PZZ673/676). SCA conditions are likely to linger through Monday morning for all of the outer waters and PZZ645, and through the afternoon for PZZ676. Increasing south winds are then expected Monday night as the cold front approaches from the north. Strong SCA winds are expected along with the front, then decreasing from the west behind the front Tuesday and Tuesday night. Wednesday through Thursday increasing NW winds will likely reach SCA levels once again. For the inner waters south of Point Conception, winds are expected to remain at SCA levels across western & southern portions of the Santa Barbara Channel through late tonight, along with choppy seas. Good confidence that winds calm to below SCA levels by early Monday morning. Monday night and Tuesday increasing S to SW winds are expected across the area. 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. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Flood Watch in effect from Monday evening through Tuesday afternoon for zones 38-88-342-344-345-348-353-355-358-362-368>375-377>380-548. (See LAXFFALOX). PZ...Small Craft Advisory in effect until 9 AM PDT Monday for zones 645-670. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Monday for zone 650. (See LAXMWWLOX). Gale Warning in effect until 3 AM PDT Monday for zones 673-676. (See LAXMWWLOX). && $$ PUBLIC...Thompson/Smith AVIATION...Black MARINE...Ciliberti SYNOPSIS...Schoenfeld/Ciliberti weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox