004 FXUS66 KLOX 140712 AFDLOX Area Forecast Discussion...UPDATED National Weather Service Los Angeles/Oxnard CA 1212 AM PDT Mon Oct 14 2019 .SYNOPSIS...13/712 PM. Most locations across the region will start the week generally cool, become warm and dry mid week, then turn cool again by the end of the week. Gusty north winds will develop late in the week and continue into the weekend. && .SHORT TERM (MON-THU)...13/920 PM. The latest infrared satellite imagery shows a weak upper-level trough of low pressure centered near the San Francisco Bay Area this evening. Onshore flow continues to strengthen tonight across southern and central California ahead of the trough. A patchy stratus pattern on the fog product imagery this evening should become more entrenched later tonight as the trough continues to push south and east into central California. The marine layer depth near 1200 feet deep earlier this evening should continue to deepen into Monday morning. A cooling trend will continue into Monday. The upper-level trough of low pressure axis will move over the area Monday, exiting the area on Monday evening. Ridging aloft will build in behind it from the west and develop weak offshore flow. ***From Previous Discussion*** Then Tuesday and Wednesday light offshore flow will be in place confining the low clouds mainly to coastal LA/Ventura Counties. At the same time a ridge will develop along the west coast. Santa Ana winds are expected to return but this will be a much weaker event than we just experienced and wind speeds aren't even expected to reach advisory levels. Temps will warm up several degrees, pushing 90 in the warmer valleys and in the lower 80s for inland coastal locations. .LONG TERM (FRI-MON)...13/1053 AM. Onshore flow quickly returns Thursday as a trough replaces the mid week ridge, bringing temps down several degrees to near or slightly below normal levels in most areas. However, this too will be short-lived as increasing north to northwest flow is expected following the Thursday trough that will bring gusty winds to areas that are susceptible to northerly flow such as srn SB County, the Central Coast, and the I5 corridor. This trend will continue into the weekend as both the GFS and ECMWF show the LAX-BFL gradient increasing to as high as 7mb by Sunday morning. This will likely wipe out most of the marine layer with the possible exception of srn LA County. Daytime highs in areas that are downslope from the winds (basically everything south of Pt Conception) will warm up to a few degrees above normal with the northerly flow. Other locations will be near to slightly below normal. Models have been consistent showing this northerly event evolving into a Santa Ana event early the following week and there are several ensemble members from both models suggesting it could be similar in strength to the event that just ended. && .AVIATION...14/0711Z. At 06Z at KLAX, the marine layer was 1400 ft deep. The top of the inversion was near 2200 ft with a temperature of 17 C. Moderate confidence in TAFs. Higher confidence in flight cats and less confidence in timing which could be off by as much as 2 hours...especially with arrival time. KLAX...Moderate confidence in TAF through 18Z. Cigs could arrive as early as 08Z. VFR transition could occur anytime between 16Z- 18Z. Good confidence in TAF from 18Z-03Z the lower confidence due to timing of return of low clouds which could occur as early as 03Z. Good confidence in no east wind component great that 3 kt. KBUR....Moderate confidence in TAF through 17Z. There is a 20 percent chc of no cigs. Cigs could arrive as early as 11Z. There is a 30 percent chc of OVC conds. Good confidence in TAF after 17Z. && .MARINE...13/802 PM. Moderate to high confidence that winds and seas will remain below SCA criteria over all of the coastal waters through Wednesday. Whereas earlier model runs had winds increasing Tuesday night, now winds will remain weak through Wednesday afternoon before beginning to increase Wednesday night. Fairly good confidence in strong SCA winds Thursday and Friday across the outer waters, and the nearshore waters south of Point Sal. It is likely that the western SBA Channel would also see SCA winds during this time. Increasing confidence in a long-period, large NW swell arriving Thursday and lasting through at least the weekend. Patchy fog is possible across the southern waters tonight into Monday morning, with patchy dense fog north of Point Conception. && .FIRE WEATHER...13/224 PM. There is increasing onshore flow this afternoon which is bringing cooler temperatures and some humidity recovery to coastal and coastal valley locations. However, dry air remains in place across the interior valleys, mountains, and deserts, where minimum humidities between 7 and 15 percent have been common today. The combination of onshore winds gusting between 20 and 25 mph and the continued dry air will bring elevated fire weather conditions this afternoon and evening across the mountains, interior valleys, and deserts. Increased marine layer influence will continue to bring further cooling and humidity recovery to coastal and valley areas on Monday, with dry air remaining across the interior. A warming and drying trend is then expected across inland areas Tuesday into Wednesday as light offshore winds develop across the mountains, deserts, and portions of the valleys. During this time, we could see elevated fire weather conditions return across the mountains, deserts, and valleys where offshore winds will gust between 20 and 30 mph, and humidities will fall to between 8 and 20 percent. There is the potential for gusty northwest to north winds across southern Santa Barbara county and the I-5 corridor Thursday night through Saturday night. There is also the potential for another round of Santa Ana winds with significant drying by next Sunday and Monday. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && .HAZARD POTENTIAL OUTLOOK (THU-MON). Gusty Sundowner winds are expected for southern Santa Barbara County Thursday through Sunday. Gusty northerly winds also possible for the Interstate 5 corridor region Friday through Sunday. && $$ PUBLIC...Hall/MW AVIATION...Rorke MARINE...Smith FIRE...Gomberg SYNOPSIS...Kj weather.gov/losangeles