FXUS66 KLOX 040525 AFDLOX Area Forecast Discussion...UPDATED National Weather Service Los Angeles/Oxnard CA 925 PM PST Tue Dec 3 2024 .SYNOPSIS...03/144 PM. Above normal temperatures are expected through the week, peaking Friday and Saturday with highs in the 70s and 80s. Locally gusty Santa Ana winds are possible Friday into early next week. Skies will be partly cloudy at times with areas of morning fog. No rain expected through the end of next week. && .SHORT TERM (TDY-FRI)...03/921 PM. ***UPDATE*** A dense fog advisory has been issued for the coastal areas of SLO and Santa Barbara Counties through Wednesday morning. Shallow marine layer coupled with light flow regime will allow dense fog to spread across the coastal areas. For now our confidence is very low that dense fog will infiltrate Ventura and LA County coastal areas, but may be needed later in the overnight period if the dense fog develops further south. No other changes were needed to the forecast this evening. ***From Previous Discussion*** Very low impact weather expected through the end of the week as high pressure over the eastern Pacific deflects all incoming systems well north and east of the area. As these systems pass us by there will be periods of light to moderate offshore flow, the next occurrence being this coming Friday when the NAM is projecting a -4.5mb LAX-DAG gradient. Not a ton of upper support with that but enough to likely generate wind gusts up to around 35 mph in the favored areas of LA/Ventura Counties and the Santa Lucias in SLO County. Most areas will get a boost in temperatures with that as well with coastal valley highs in the 80s and most other areas in the 70s. In the meantime, a little cooling today and Wednesday with a return to light onshore flow before trending back up Thursday. Some night and morning low clouds and locally dense fog expected as well. .LONG TERM (SAT-TUE)...03/142 PM. Another warm early December day on Saturday as light offshore continues. Then 4-8 degrees of cooling most areas Sunday as gradients shift back onshore. Sunday night into Monday an upper low will drop south out of Canada and into the Great Basin. Models gradients have been bouncing around quite a bit, at one point showing almost a -9mb LAX-DAG gradient Monday morning. More recent deterministic runs have settled in the -4 to -6 range (peaking Tuesday) with 850mb winds between 35 and 45kt. The deterministic runs do show some decent cold air advection with thicknesses ranging from 549dam at the coast to 538 across the deserts. However, most of the EPS wind forecasts are only in the 30-40 mph range, suggesting that the deterministic models are on the higher end in terms of offshore strength. So the most likely outcome at this point is a moderate Santa Ana with peak gusts in the 35-45 mph range, but with maybe a 10-20 percent chance of a strong event with gusts up to 60 mph. Given the cold air advection and moderate upper support Santa Ana winds should have no trouble reaching the coast and well out through the coastal waters. High temperatures will drop at least 6-12 degrees starting Monday, more so inland than at the coast and remain on the cooler side. If the upper low makes a closer pass, temperatures may be even cooler. Offshore flow expected to linger into mid week. && .AVIATION...04/0034Z. At 2357Z at KLAX, the marine layer was 700 feet deep, with an inversion top at 2100 ft and a maximum temperature of 16 C. High confidence in desert sites, moderate confidence in coasts and valleys sites. Timing of cig development and flight category chances may be off by +/- 3 hours tonight. Additionally during cigs, period of dense fog with VSBY as low as 1/4SM, will be possible for all coasts and valleys. The greatest chances for dense fog are at KSBP and KSMX. There is a 40% chance of no cigs developing at KBUR and KVNY tonight. KLAX...Moderate confidence in TAF. Timing of cig development and flight category chances may be off by +/- 3 hours tonight. There is a 20% chance of dense fog with VSBY as low as 1/4SM-1/2SM during cigs. No significant easterly wind component is expected. KBUR...Moderate confidence in TAF. There is a 40% chance of no cigs developing through the period. && .MARINE...03/756 PM. For the Outer Waters, moderate to high confidence in current forecast. Through Wednesday morning, high confidence in winds and seas remaining below Small Craft Advisory (SCA) levels. From Wednesday afternoon through Saturday evening, there is a 30-50% chance of SCA level winds (with the best chances Thursday afternoon and evening). For Sunday, there is a 20-30% chance of SCA level winds, but a 50-70% chance of SCA level seas. For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Through Wednesday night, high confidence in winds and seas remaining below SCA level. For Thursday, there is 30% chance of SCA level winds in the afternoon and evening hours. For Friday through Sunday, high confidence in winds remaining below SCA levels, but a 30-40% chance of SCA level seas on Sunday. For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. From Point Mugu to Santa Monica, there is a 20% chance of SCA level northeast winds late Wednesday night/Thursday morning then a 30-40% chance of SCA level northeast winds late Thursday night/Friday morning. Otherwise for the rest of the southern Inner Waters, high confidence in winds and seas remaining below SCA levels through Sunday. Patchy dense fog may affect the coastal waters tonight and Wednesday morning with visibility of one nautical mile or less. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Dense Fog Advisory in effect until 9 AM PST Wednesday for zones 340-341-346>350. (See LAXNPWLOX). PZ...NONE. && $$ PUBLIC...MW/JMB AVIATION...Schoenfeld MARINE...RAT/Schoenfeld SYNOPSIS...MW weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox