115 FXUS66 KLOX 121810 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 1010 AM PST Wed Dec 12 2018 .SYNOPSIS...12/804 AM. Partly cloudy skies today with the passing of a low pressure system. A ridge of high pressure will warm temperatures Thursday to several degrees above normal. Another low pressure to the north will pass through Friday to bring cloudy skies and cooler temperatures to most areas. && .SHORT TERM (TDY-FRI)...12/1008 AM. Strong northerly flow aloft continues along with decent northerly surface gradients. Localized advisory level winds finally developed across the Santa Ynez range, albeit late, and same with the I5 corridor though only Sandberg is reporting winds in excess of 40 mph so it's still very isolated there and likely at least partly due to mountain wave activity. Getting a few more high clouds spilling over the top of the eastern Pacific ridge than expected so a partly cloudy forecast looks appropriate. The stratus that developed over srn LA County this morning is starting to drift northwest as the NAM suggested yesterday and could reach the Ventura and even southeastern SB coast by this afternoon. Either way the increase in onshore flow and boundary layer moisture will cool temps at lower elevations, especially south of Pt Conception. Temps farther inland will warm up as the ridge expands into California. Rest of the forecast looks on track. 12z models still suggesting a low end advisory level Santa Ana event at best tomorrow with little if any upper support. Will see how the higher res models handle the winds and decide whether an advisory is warranted. ***From previous discussion*** Another weak trof will scoot down over the ridge this afternoon. More importantly a strong cold sfc high will develop over the great basin and will push the KDAG grad all the way to -7.5 MB by Thu morning. There is no upper of thermal support but that much of a sfc push will likely bring low end advisory wind gusts to some mtn and vly locations. Max temps across the coasts and vly will jump up 3 to 6 degree and will be above normal. Hgts do not change much and the interior will see little change in temperatures. The ridge will shift east Friday as the next trough pushes closer to the coast. clouds will increase through the day as plenty of mid and high level clouds move in ahead of the trof. What was once a weak front with just enough oomph to bring some rain to northern SLO county is now a faded memory and the day will be dry. Hgts will lower through the day as the trof approaches and the offshore flow will relax. Both of these will bring a couple of degrees of cooling to the entire forecast area. .LONG TERM (SAT-TUE)...12/314 AM. Skies will clear on Saturday as the trof pushes off to the east. Hgts will remain about the same as west flow establishes itself over southern CA. There will still be some offshore flow but it will be light. Max temps will war a degree or two due to the additional sunshine and will be above normal. A larger trof will approach the area on Sunday. It will likely bring clouds and lowering hgts which will in turn lower max temps some. Despite the cooling max temps should remain a few degrees above normal. Both the GFS and EC have been slowing the approach of the trof and front and its doubtful that any rain will fall during the day. Both the GFS and EC agree that the trof passage will be both weaker and slower than previously forecast. Still quite a bit of uncertainty in the exact timing of the rain but right now it looks like most areas (esp areas north of Pt Conception) will see a little rain either late Sunday night or sometime Monday. Rainfall amounts will be on the light side. Skies will clear Monday night in the wake of the trof and a little sub advisory offshore wind event will set up. Both the GFS and EC are in excellent agreement for mid to late next week showing a strong high pressure ridge over California with a 590dm center just southwest of Pt Conception. This combined with light to moderate offshore flow should lead to a significant warm up for the remainder of next week. Could be some fire weather concerns across LA/Ventura counties with low humidities, gusty northeast winds, and well above normal temperatures. && .AVIATION...12/1143Z. At 1051Z at KLAX, the marine layer was 1000 feet deep. The top of the inversion was at 1700 ft with a temperature of 18 C. Overall high confidence in the 00Z TAF package with VFR conds, except for low to moderate confidence in KPRB, KLAX, KSMO and KLGB. There is a 50 percent that IFR/MVFR cigs occur through 17z. Except KPRB has a 40% chance for VLIFR to IFR cigs through 16z KLAX...Moderate confidence in 12z TAF through 17Z with IFR/MVFR Cigs...otherwise high confidence after that. There is a 20 percent chc of an east wind component greater of 8 kt through 16Z. KBUR...high confidence in CAVU TAF. 20$ chance for MVFR cigs from 13z-17z. && .MARINE...12/925 AM. For the Outer Waters, high confidence in current forecast. Small Craft Advisory (SCA) level winds will continue through this evening. For Thursday through the weekend, SCA level seas are possible as a long-period swell moves into the coastal waters. For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. There is a 20% chance of SCA level northwest winds this afternoon and evening. For Thursday through the weekend, SCA level seas are possible. For the Inner Waters south of Point Conception, moderate confidence in current forecast. There is a 30% chance of SCA level northeast winds on Thursday nearshore from Ventura south to Santa Monica. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory in effect until noon PST today for zones 39-52. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 9 PM PST this evening for zones 670-673-676. (See LAXMWWLOX). && .HAZARD POTENTIAL OUTLOOK (FRI-TUE). Very high surf and dangerous rip currents are expected Monday and Tuesday. && $$ PUBLIC...MW/Rorke AVIATION...Kaplan MARINE...Sweet SYNOPSIS...B/KS weather.gov/losangeles