181 FXUS66 KLOX 161042 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 242 AM PST Wed Dec 16 2020 .SYNOPSIS...15/136 PM. Light offshore flow will bring warmer and continued dry conditions to the region through Wednesday, along with locally gusty northeast winds through and below passes and canyons. A weak weather system will move over the region early Thursday with a chance of light rain north of Point Conception. A warming trend for the weekend as high pressure builds across the region with some gusty north winds at times. && .SHORT TERM (TDY-FRI)...15/757 PM. ***UPDATE*** Upper level ridging was bringing mostly clear skies to the region this evening with little change expected overnight. Offshore pressure gradients continued to the N and E, with LAX-DAG at -3.1 mb at 03Z, while the LAX-BFL was at -4.5 mb. The NAM was forecasting the LAX-DAG gradient to fall to -4.6 mb at 12Z, with the LAX-BFL remaining around 4.0 mb. These offshore pressure gradients will help to bring gusty mainly sub-advisory NE winds to a lot of the foothills and mtns overnight, with breezy NE winds for the vlys to the coast. The winds will be most prevalent over VTU/L.A. Counties, and western SLO/SBA Counties especially in the hills. ***From Previous Discussion*** Santa Ana winds across LA/Ventura Counties decreasing going into the afternoon but should hover in the 15-30 mph range, especially inland, into Wednesday morning before turning onshore prior to the arrival of the next weak cold front. Temps warmed up a few degrees today and are expected to warm up a few more tomorrow as lingering cold air from the previous upper low exits and ridging develops aloft. Thursday morning a weakening cold front will pass through the area, probably dropping some very light rain across northwest SLO County with decreasing chances to the south, and basically little to no chance south of SBA. May have just enough gas left to drop some light precip across the northern mountain slopes near the Kern Count line. Otherwise the front will wash out and kick up some gusty westerly winds behind it Thu afternoon, especially near the coast. Temps will cool down several degrees Thursday with highs mostly in the low to mid 60s at lower elevations. We'll transition to northerly flow Thursday night and northeast Friday morning but likely below advisory levels in most areas except possibly across the SB south coast and I5 corridor. Temps Friday a couple degrees warmer than Thursday but still mostly in the 60s. .LONG TERM (SAT-TUE)...15/134 PM. The weekend will be dominated by a ridge along the West Coast that will keep skies clear and highs 3-6 degrees above normal. Though overnight lows will be chilly in wind protected locations. Gusty north to northeast winds expected at times, especially srn SB County and the I5 corridor region. Northerly winds expected to decrease early next week with generally quiet weather through Tuesday. Models continue to have difficulty with the upper pattern next week but generally seem to settling on a dry pattern through Xmas. The number of ensemble members supporting even light rain is very small as it looks like the storm track will be riding well north of southern California for at least the next 10 days. The GFS has been going back and forth on a possible moderate offshore wind event on the 24th or 25th so will keep a close eye on that. && .AVIATION...16/0648Z. At 05Z, there was no marine layer at KLAX. High confidence in the current forecast. VFR conditions are expected at all terminals. There is a slight chance of moderate low-level wind shear and turbulence for Los Angeles and Ventura County terminals and Central Coast terminals. KLAX...VFR conditions are expected through the period. There is a 10 percent chance of moderate low-level wind shear and turbulence. KBUR...VFR conditions are expected through the period. There is a 20 percent chance of moderate low-level wind shear and turbulence. && .MARINE...16/241 AM. High confidence in Small Craft Advisory (SCA) hazardous seas over 10 feet across the waters along the Central Coast to San Nicolas Island through at least Thursday. The SCAs currently in effect have been extended through at least Friday evening as gusty NW winds will develop once the seas lower to below 10 feet late Thursday into Friday morning. The swell could result in breaking waves over the harbor entrances of Morro Bay and Ventura. There will be a return of gusty northwest winds across much of the waters by Thursday afternoon with a 30% chance of gales. Across the waters inside the Southern California Bight, high confidence that winds and seas will remain below SCA level through Thursday morning, with a 70% chance for small Craft advisories needed for both PZZ650-655 Thursday afternoon through the overnight hours. Otherwise, winds look below SCA thresholds this weekend, except for some local offshore winds between Oxnard and Malibu in the morning hours Fri/Sat. 30-40% chance that a SCA will be needed for these areas during the morning hours. && .BEACHES...16/207 AM. A large, long-period west to northwest swell will continue to impact the coastal areas through Thursday evening with the highest surf affecting the Central Coast and the exposed west facing beaches of the Ventura County Coast. The High Surf Advisory for the Central Coast was extended earlier last evening through Thursday evening, where breaking waves of 10 to 15 feet are expected, then lowering to 8 to 12 feet on Thursday. Latest guidance is indicating that the large swell may continue through Friday reaching minimum high surf thresholds of 10 feet. Therefore later shifts may need to consider extending the High Surf Advisory through Friday. The High Surf Advisory for the Ventura Coast has also been extended through Thursday evening. Although there will be a brief lull this morning when surf lowers to around 4 to 6 feet, the swell is expected to increase once again by this afternoon translating to surf of 6 to 9 feet through Thursday, then diminishing to below high surf thresholds late Thursday evening through the overnight hours. Along the same lines the Beach Hazards Statement for the LA Coast and west- facing beaches of the Santa Barbara South Coast have also been extended through mid- morning Thursday with surf 3 to 5 feet for exposed west facing beaches. Local sets to 6 feet will be possible. High tides will remain close to 6.5 feet this morning, so there is a chance of minor coastal flooding of beach parking lots. High tide will be lower on Thursday morning which will lower the risk of local coastal flooding. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...High Surf Advisory in effect until 9 PM PST Thursday for zones 34-35-40. (See LAXCFWLOX). Wind Advisory in effect until 9 AM PST this morning for zone 34. (See LAXNPWLOX). Beach Hazards Statement in effect through Thursday morning for zones 39-41-87. (See LAXCFWLOX). Frost Advisory in effect until 9 AM PST this morning for zone 44. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 3 AM PST Thursday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 9 PM PST Friday for zones 670-673-676. (See LAXMWWLOX). && .HAZARD POTENTIAL OUTLOOK (FRI-TUE). High surf and/or dangerous rip currents will impact most beaches through Friday. Gusty northerly winds are possible across parts of the area Friday through Sunday. && $$ PUBLIC...MW/Sirard AVIATION...Hall MARINE...Kaplan BEACHES...Kaplan SYNOPSIS...MW weather.gov/losangeles