564 FXUS66 KLOX 140011 AFDLOX Area Forecast Discussion...UPDATED National Weather Service Los Angeles/Oxnard CA 511 PM PDT Sat Jul 13 2019 .SYNOPSIS...13/1149 AM. Strong high pressure remains in control through Monday, continuing the heat wave away from the coast. Night through morning clouds and fog will be confined to coastal areas. An upper level trough will bring a cooling trend Tuesday through Thursday, with an increase in night through morning low clouds and fog. && .SHORT TERM (TDY-TUE)...13/245 PM. There was a shallow marine inversion early this afternoon around 800 ft at LAX. Low clouds persisted along many of the beaches this afternoon, otherwise sunny skies covered the forecast area which will continue through sunset. Temps early this afternoon have climbed into the 90s to low 100s for the vlys, lower mtns and deserts, and will peak later this afternoon into the mid 90s to 105 or more. A large upper level high pressure system will persist over the srn Rockies into AZ thru Mon, with srn CA on the western periphery of the upper high. H5 heights over swrn CA will be generally in the 589 to 592 dm range thru the period, with southerly flow aloft today turning more SW to W Sun thru Mon. An upper level trough will approach the area from the e Pac Mon night then move inland on Tue. The marine inversion will remain shallow and strong thru Mon and should remain below 1000 ft deep before increasing slightly for Mon night into Tue. Varying amounts of night and morning low clouds and fog can be expected along the coastal plain thru Tue, except northerly flow will keep the SBA County S coast free of the low clouds Sun night through Tue. Otherwise, the mostly clear skies will continue thru the period. Temps will remain much above normal away from the immediate coast on Sun. Highs should reach the mid 90s to 102 for the vlys and lower mtns, with 102 to 105 in the Antelope Vly. Temps should lower slightly for Mon but remain several degrees above normal for most areas. The vlys and lower mtns on Mon should reach the 90s to around 100, with low 100s in the Antelope Vly. it will turn cooler on Tue to near to slightly above normal with the warmest vlys and lower mtns reaching the upper 80s to mid 90s, except 95 to 100 in the Antelope Vly. A Heat Advisory remains in effect for lower mountain elevations, for the valleys of L.A. County, the Interior Valleys of SLO County and the Cuyama Valley through Sunday evening, and these may need to be extended into Mon as well. Heat advisories are not issued for the Antelope Valley, but max temps should approach excessive heat warning levels this afternoon and again on Sun. Moderate onshore gradients will help to bring locally gusty S to W winds to the foothills, mtns and deserts each afternoon and evening thru Mon, but turn slightly stronger on Tue thanks to increasing onshore gradients. There will also be an increase in the northerly gradients across SBA County by Sun evening and more so Mon evening, with the potential for hot sundowner conditions for the SBA County S coast and Santa Ynez Range. The strongest winds Sun evening should be mainly W of Goleta, but then spread across much this area Mon evening, with gusts up to 30 mph possible in the typically windy locations late Monday afternoon and evening, and gusts over 50 mph will be possible in places such as Refugio and Gaviota. Wind advisories will likely be needed for the SBA County S coast and mtns Mon evening. Gusty NW winds can also be expected for the mtns around the I-5 corridor Mon evening. With the hot northerly flow expected for SBA County Sun and Mon, temps should increase well into the 90s below the windy passes and canyons Sun evening, with temps into the 90s to around 100 possible Mon evening all the way down to the immediate coast. Low temps could even be only in the lower 80s in the warmest foothill areas Sun night, and mid to upper 80s in these areas Mon night. The high temperatures combined with low humidities (including poor recoveries in the foothills and mountains), and locally gusty winds will bring an extended period of elevated fire weather concerns across interior sections through Mon night. This will increase across SBA County Monday night as winds increase. This situation will be monitored closely. .LONG TERM (WED-SAT)...13/246 PM. The EC and GFS both have a broad upper level trough over CA Wed. This trof will weaken Thu then weak upper level troffiness will persist along and off the central and SW CA coast Fri and Sat. Little change in the overall weather pattern can be expected during the extended period. The marine inversion should increase to around 1500 ft or perhaps slightly higher at times. Night and morning low clouds and fog will prevail for the coast and adjacent vlys thru the period. Otherwise, mostly clear skies can be expected. Temps will be near normal to slightly below normal overall each day. The warmest vlys and lower mtns should reach mainly into the mid 80s to lower 90s Wed thru Sat. && .AVIATION...14/0008Z. At 23Z at KLAX...The marine layer was 800 ft deep. The top of the inversion was around 2000 feet with a temperature 27 C. Good confidence in non coastal TAFs. Low confidence in coastal TAFs. Arrival and Dissipation time of low clouds could be off by as much as three hours. There is 30 percent chc 1/2SM VV002 at all sites 09Z-15Z. KLAX... Low confidence in TAF. Low clouds could arrive as early as 03Z or as late as 08Z. There is 30 percent chc 1/2SM VV002 at all sites 09Z-15Z. Good confidence in no east wind component greater than 4kt. KBUR...Very good confidence in TAF. && .MARINE...13/154 PM. For the Outer Waters... There is a seventy percent chance of Small Craft Advisory (SCA) level winds through Tuesday with a forty percent chance of SCA winds on Wednesday. Winds may decrease to below SCA level during the morning and early afternoon periods. For the Inner Waters north of Point Sal... There is a sixty percent chance of SCA level winds each afternoon and evening on Sunday and Monday and a forty percent chance on Tuesday. Otherwise conditions will remain below SCA levels. For the Inner Waters south of Point Conception... There is a forty percent chance of SCA level winds across the western half of the Santa Barbara Channel Sunday through Tuesday during the late afternoon and evening hours. Otherwise conditions will remain below SCA levels through the forecast period. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Heat Advisory in effect until 8 PM PDT Sunday for zones 37-38-51>54-88-547. (See LAXNPWLOX). PZ...Small Craft Advisory in effect from 3 PM Sunday to 3 AM PDT Tuesday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Wednesday for zones 670-673-676. (See LAXMWWLOX). && .HAZARD POTENTIAL OUTLOOK (TUE-SAT). No significant hazards expected. && $$ PUBLIC...Sirard AVIATION...Rorke MARINE...Kj SYNOPSIS...DB/Stewart weather.gov/losangeles