057 FXUS66 KLOX 151751 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 951 AM PST Thu Dec 15 2022 .SYNOPSIS...15/231 AM. Temperatures will warm slightly over the next few days but will remain below normal. Dry weather is expected into next week. Gusty Santa Ana winds are expected Friday into Saturday across Ventura and Los Angeles Counties. && .SHORT TERM (TDY-SAT)...15/950 AM. ***UPDATE*** Increasing high clouds from a system well offshore will clutter the skies over the next few days but otherwise our dry pattern will continue. Even drier the next couple days as a low grade Santa Ana wind event develops. This will bring gusty (up to around 45 mph) winds through the usual Santa Ana wind corridor in Ventura/LA Counties. Will be issuing wind advisories for these areas this afternoon, with onset of winds expected sometime this evening and peaking between sunrise and noon Friday. Not expecting to need any frost advisories tonight with the developing Santa Ana winds and increasing high clouds that will provide some insulation. ***From Previous Discussion*** A Santa Ana wind event will set up early Friday as a weak trof pushes through NV and sfc high pressure builds into the Great Basin the NAM (which tends to over forecast) has a 6 mb offshore push from the east. The GFS and EC are 1 to 2 MB weaker. There will be a little less push from the north only about 2 MB. Not much upper support, but enough cold air advection to produce low end wind advisories 10 or so miles either side of the VTA/LA county line. The winds will quickly diminish by early afternoon. Otherwise the day will start out with a fair amount of high clouds but these should diminish later in the morning. Max temps will warm with the offshore flow but the Antelope Vly and VTA/LA mtns will cool due to the cold air advection. The areas will warming will approach normals but still come in below. Saturday's gradients remain just as offshore as Friday morning's. There is, however, little or no thermal or upper support. So while there will be gusty canyon winds in the morning they will not be close to advisory levels. Falling hgts and the reduction in offshore flow will cool almost all areas 2 to 3 degrees. .LONG TERM (SUN-WED)...15/308 AM. GFS and EC deterministic runs as well as their respective ensembles are in good agreement for Sunday. Things go sideways on Monday and beyond as the deterministic quickly fall out of phase and the ensemble spreads widen noticeably. Weak ridging will move in on Sunday. Gradients will be weakly offshore from both the north and the east. Skies will be partly cloudy. Max temps will bump up 2 to 4 degrees except across the Antelope Vly and inner mtn areas were the absence of cool air advection will bring 4 to 8 degrees of warming. It will be dry Monday through Wednesday. The mdl disagreement greatly reduces confidence in the smaller details. The two deterministic mdls are 180 degrees out of phase and the ensembles are not showing much in the way of agreement. So lower confidence in the cloud and temp forecast. It does seem like the offshore flow will increase in strength each day and this will bring a rise in temps with some above normal max temps fcst next Wednesday. But the confidence in the forecast is low and may well change. && .AVIATION...15/1640Z. At 1545Z, there was no marine inversion or marine layer at KLAX. Overall, high confidence in 18Z TAF package as developing offshore flow will keep most sites VFR through the period. The only exception will be KPRB where there is a 40% chance of MVFR VSBYs 12Z-16Z. Late tonight and Friday morning, offshore flow will bring some gusty northeast winds to KOXR/KCMA/KVNY with turbulence/LLWS likely across the foothills and mountains. KLAX...High confidence in 18Z TAF as VFR conditions are anticipated through the period. There is a 10% chance of easterly winds greater than 8 knots 15Z-20Z. KBUR...High confidence in 18Z TAF as VFR conditions are anticipated through the period. && .MARINE...15/840 AM. For the Outer Waters, high confidence in the current forecast. Today through Monday, winds and seas will remain below Small Craft Advisory (SCA). For the Inner Waters north of Point Sal, high confidence in the current forecast. Today through Monday, winds and seas will remain below SCA levels. For the Inner Waters south of Point Conception, moderate to high confidence in the current forecast. Late tonight through Friday morning, there is a 40% chance of SCA level northeast winds from Ventura south to Santa Monica then a 20% chance of SCA level northeast winds in the same area Saturday morning. Otherwise, high confidence in winds and seas remaining below SCA levels through Monday. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...MW/Rorke AVIATION...RAT MARINE...RAT SYNOPSIS...30 weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox