Area Forecast Discussion
Issued by NWS Los Angeles, CA

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270 FXUS66 KLOX 042125 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 225 PM PDT Sat May 4 2024 .SYNOPSIS...
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04/222 PM. A cold storm system will move over the region through Sunday bringing periods of light rain to the area through tonight. Temperatures will be much cooler than normal through Sunday and there will be gusty winds at times. Dry and warmer weather is expected next week.
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&& .SHORT TERM (TDY-TUE)...
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04/214 PM. A cold but weakening storm is moving into the area this afternoon. The leading edge of the rain is close to the SLO/Monterey county line as of 2pm and it will continue to progress south and east across the area through the pre-dawn hours Sunday. Sprinkles/showers are expected to last no longer than 3-4 hours in any one location. Storms like this that move inland over northern California and move south along the Sierra spine typically result in lighter rainfall amounts locally, and especially from southeast Santa Barbara to western LA County due to downsloping flow off the Transverse range. Northwest SLO County still expecting to be the winner locally with amounts from a half to three quarters of an inch, but then dropping rapidly to the south. There may be a little reinforcing southwest flow over southeastern LA County that will generate slightly higher rain rates there and especially in the eastern San Gabriel Mountains, but amounts there should top off at around a half inch. Snow levels along the frontal boundary are way up above 8000 feet so only the highest peaks will see any frozen precip. All the precip will be out of the area before the sun rises Sunday, except for possibly some lingering light showers on the north facing slopes Sunday morning. Otherwise, clearing skies expected with plenty of sunshine but temperatures well below normal. The storm is generating some gusty westerly winds today and these will continue into Sunday as well, strongest in the mountains and Antelope Valley. Dry and warmer weather expected Monday and Tuesday, but with some gusty northerly winds at times, especially southern Santa Barbara County and the I5 corridor. .LONG TERM (WED-SAT)...04/221 PM. A slow warming trend is expected to continue through next week, but with some uncertainties later in the week and next weekend as some model solutions show a weak upper low developing over northern California. The only expected outcome from this would be slightly cooler temperatures than currently predicted. Otherwise, with the exception of daily north winds across the mountains and southern Santa Barbara County, weather conditions are expected to low impact with highs near to slightly above normal levels by mid week.
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&& .AVIATION...04/1701Z. At 1600Z at KLAX, the marine layer was 3800 feet deep. The top of the inversion was at 5600 feet with a temperature of 13 degrees Celsius. Overall, low to moderate confidence in 18Z TAF package. Combination of deep marine inversion with approaching weak system will bring clouds and visibilities ranging from IFR to MVFR through the period. Confidence in timing of flight category changes will be low through the period. Light showers will be possible across the area late this afternoon through tonight. KLAX...Moderate confidence in 18Z TAF. There is a 30% chance of MVFR CIGs 18Z-04Z. For tonight, high confidence in return of MVFR CIGs, but only moderate confidence in timing (could be +/- 3 hours of current 04Z forecast). High confidence in VFR conditions after 15Z. No significant easterly wind component is expected. KBUR...Moderate confidence in 18Z TAF. There is a 40% chance that VFR conditions will develop 18Z-03Z. For tonight, high confidence in return of MVFR CIGs, but only moderate confidence in timing (could be +/- 3 hours of current 03Z forecast). && .MARINE...
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04/212 PM. For the Outer Waters, moderate to high confidence in current forecast. Tonight through Wednesday, high confidence in combination of Small Craft Advisory (SCA) level winds and seas (with SCA level seas developing Tuesday/Wednesday). There is a 50% chance of Gale force winds Sunday afternoon through Sunday night then again Tuesday and Tuesday night. For Thursday, there is a 40-50% chance of SCA level winds. For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Tonight through Wednesday, high confidence in a combination of SCA level winds and seas (with the SCA level seas developing Tuesday/Wednesday). There is a 30% chance of Gale force winds Sunday afternoon/evening then again Tuesday/Wednesday. For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Tonight through Sunday night, high confidence in SCA level winds (with the strongest winds across western sections). There is a 50% chance of Gale force winds Sunday afternoon and Sunday night. For Monday through Wednesday, there is a 60-70% chance of SCA level winds across the western half of the Santa Barbara Channel and a 30% chance of SCA level winds elsewhere. For Thursday, high confidence in winds and seas remaining below SCA levels.
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&& .LOX WATCHES/WARNINGS/ADVISORIES...
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CA...Wind Advisory remains in effect from 10 AM to 9 PM PDT Sunday for zones 87-340-341-346>348-354-355-362-366. (See LAXNPWLOX). Wind Advisory remains in effect from 11 PM this evening to 3 AM PDT Monday for zones 349>353-376>378. (See LAXNPWLOX). Wind Advisory remains in effect until 5 AM PDT Sunday for zones 379>383. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 3 AM PDT Sunday for zones 645-670. (See LAXMWWLOX). Small Craft Advisory in effect from 9 PM this evening to 3 PM PDT Sunday for zones 650-655. (See LAXMWWLOX). Gale Watch in effect from Sunday afternoon through late Sunday night for zones 650-655-673-676. (See LAXMWWLOX). Small Craft Advisory in effect until 3 PM PDT Sunday for zones 673-676. (See LAXMWWLOX).
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&& $$ PUBLIC...MW AVIATION...RAT MARINE...RAT SYNOPSIS...MW weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox