199 FXUS66 KLOX 211804 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 1104 AM PDT Thu Mar 21 2019 Updated Aviation Section .SYNOPSIS...21/752 AM. Shower activity will end today through most of the region, with lingering showers possible in the mountains tonight. Clouds increase Friday as another storm system brings a chance of rain north of Point Conception Friday night. Rain and snow are possible in the mountains Saturday. Below normal temperatures are expected through the rest of the week. && .SHORT TERM (TDY-SAT)...21/948 AM. Another low pressure system coming through the negatively tilted trough over California today. Visible satellite imagery is nicely capturing the low level circulation drifting south about 60 miles west of Santa Maria this morning. The rain bands ahead of it were a little more energetic than expected and generated rain rates up to .2-.3"/hr as they moved through SB County this morning and now moving into Ventura County. This activity will continue moving southeast and into LA County shortly and into the afternoon. Hi res models indicate some additional enhancement over LA County this afternoon as the showers pick up some additional lift from the mountains and colder air aloft that could lead to slightly higher rates there, but still below critical levels and not expecting thunderstorms locally. Showers expected to rapidly decrease this evening and be pretty much done by midnight with clearing skies and northwest flow developing. Exception being the Grapevine area which likely will see some low clouds and fog through early Friday as moisture banks up from the southern San Joaquin Valley. ***From previous discussion*** A little ridge moves into the state on Friday. It is not that warm a ridge and hgts only rise to 566 DM. Skies will be partly cloudy as the ridge is not strong enough to prevent some mid and high level clouds to sneak through. Max temps will jump about 5 degrees but will still come in blo normal. The barest of trofs moves over the state on Saturday it does little more than to knock down the trof. It will bring a chc of showers to the Central Coast and the mtns. At this time it looks too weak to bring any showers to the rest of the area. Max temps will cool 2 or 3 degrees and will end up 4 to 8 degrees blo normals. .LONG TERM (SUN-WED)...21/326 AM. Another weak ridge moves into the state on Sunday. More importantly some offshore flow develops. Skies will clear out and max temps will rise about 5 degrees and most cst and vly locations will have max temps a degree or two either side of 70. Still 2 to 3 degrees blo normal. An upper low will move into the north of the state on Monday and will push the ridge off to the east. Clouds will increase esp over SLO and SBA counties, but it will remain dry over almost of the area with the only chc of rain over the NW corner of SLO county. Despite the ridge moving off hgts will continue to rise up from the south by a broad ridge that is also responsible for the north track of the upper low. These higher hgts will lead to a few degrees of warming esp over the less cloudy VTA and LA counties. The upper low pulls more to the north and its associated front does not make much in the way of eastward progress and the chc of rain will be confined to SLO and SBA counties. The rest of the area will see mostly cloudy skies. Max temps will cool north of Pt Conception but will not change much to the south. The front finally makes its eastward push Tuesday night and Wednesday. A chance of rain will develop over all over the 4 county area and persist into Wednesday afternoon. This really looks like a late March system with minimal rainfall amounts and rates. Hgts do collapse and along with overcast skies max temps will roundly fall to 6 to 8 degrees blo normals. && .AVIATION...21/1759Z. At 17Z, there was no marine layer or inversion at KLAX. Moderate confidence in VFR SCT-BKN050 common through 02Z, with MVFR BKN025 common under -SHRA. After 03Z, moderate confidence in VFR conditions common. There is a small chance of IFR/LIFR post- rain FG/BR around 12Z Friday in random locations, with the highest chance at KPRB. KLAX...Moderate confidence in -SHRA at times, and VFR CIGS common, except for MVFR CIGS under some showers. Moderate confidence in timing +/- 2 hours. Moderate confidence in VFR conditions tonight. KBUR...Moderate confidence in -SHRA at times, and VFR CIGS common, except for MVFR CIGS under some showers. Moderate confidence in timing +/- 2 hours. Moderate confidence in VFR conditions tonight, but there is a 10 percent chance if IFR/LIFR post-rain FG/BR around 12Z Friday. && .MARINE...21/949 AM. Moderate confidence in NO thunderstorms today, but showers will persist through the day. Gusty west to northwest winds will increase this afternoon and evening south of Point Conception, with a 60 percent chance of reaching Small Craft Advisory (SCA) strength. These winds will also generate choppy seas on top of the long period west swell. Similar conditions are likely on Friday. Northwest winds will increase some on Saturday with SCA likely off the Central Coast. && .BEACHES...21/414 AM. A relatively large, long period west-northwest swell will slowly subside today and surf should decrease below High Surf Advisory levels by late afternoon. Another long period west-northwest swell could bring high surf to area beaches again late Sat and Sun. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...High Surf Advisory in effect until 3 PM PDT this afternoon for zones 40-41-87. (See LAXCFWLOX). PZ...Small Craft Advisory in effect from 3 PM this afternoon to 9 PM PDT this evening for zones 650-655-676. (See LAXMWWLOX). && .HAZARD POTENTIAL OUTLOOK (SAT-WED). High surf and dangerous rip currents are expected over the weekend. && $$ PUBLIC...MW/Rorke AVIATION...Kittell MARINE...Kittell BEACHES...DB SYNOPSIS...Phillips weather.gov/losangeles