091 FXUS66 KLOX 121146 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 446 AM PDT Sun May 12 2019 .SYNOPSIS...12/335 AM. Except for a slight chance of thunderstorms in the mountains this afternoon and evening, dry weather is expected through Tuesday, and temperatures will be near to slightly above normal. An approaching upper trough will bring cooler weather to the region Wednesday, then a chance of showers Thursday as it moves across the region. Lingering showers are possible Friday, then dry weather is expected Saturday. && .SHORT TERM (TDY-TUE)...12/446 AM. Low clouds were widespread on the Central Coast and in the Santa Ynez and Salinas Valleys early this morning. Some clouds have pushed into immediate coastal sections of L.A./VTU Counties, and these should become more widespread by daybreak. At least patchy low clouds will likely spread into the San Gabriel Valley, the valleys of VTU County, and the south coast of SBA County as well. Some gusty northwest to north winds were affecting western portions of the SBA County south coast near Gaviota, but were too localized to require advisories. Last night's WRF did not have a handle on the low clouds field this morning, but it did seem to be doing a decent job this morning. Clouds should clear out in most areas by mid to late morning, though the WRF suggests some clouds could linger at the beaches into the afternoon. Max temps today should be similar to those on Sat, except they will likely be down several degrees on the Central Coast, where low level northeast flow generated quite a bit of warming on Sat. Overall, temps should be fairly close to normal for mid May in most areas. The WRF shows some fairly good instability in the mountains of VTU County and eastern L.A. County this afternoon, but moisture will be lacking. There will likely be some buildups, and there may be just enough lingering moisture behind the departing upper low for a couple of showers/tstorms this afternoon and evening. Will keep the slight chance pops in the forecast, but most likely there will be nothing more than some buildups. A positively tilted upper ridge will build into the region tonight and Mon, then it will drift slowly eastward late Mon thru Tue. As it begins to move away from the region, it will amplify. Therefore, heights will remain about the same on Tue, and could even rise a bit across the southern and eastern parts of the region. Expect areas of night through morning low clouds and fog in coastal and lower valley areas tonight through Tue. Max temps on Mon should be similar to those today. On Tue, temps may edge upward in coastal and valley areas south of Pt Conception as onshore gradients weaken. North of Point Conception, expect little change in temps of slight cooling due to an increase in high clouds in the afternoon as the flow aloft turns southwesterly ahead of an approaching trough. .LONG TERM (WED-SAT)...12/443 AM. An upper trough will approach the West Coast on Wed. The marine layer will likely deepen Tue night and Wed morning, with low clouds likely in all coastal and valley areas. High clouds will overspread the region during the day. Wed should end up being a mostly cloudy day, though there may be some sun across southern and eastern portions of the forecast area. There will be several degrees of cooling in all areas on Wed. Operational runs of the GFS and the EC continue to exhibit significant difference with the respect to rain from the trough moving into the West Coast. The GFS has been quite inconsistent from run to run, but generally has been much drier than the EC. The 06Z run of the GFS has trended wetter, but was still not as wet as the 00Z EC which actually shows over 1 inch of rain across parts of L.A. County. The latest EC is also somewhat faster with this system than its previous runs, with rain spreading into the Central Coast Wed evening, and the bulk of the rain late Wed night and Thu morning. The GFS holds the rain off until Thu morning, with the bulk of the rain Thu afternoon into Thu night, and showers lingering through Fri afternoon. Have bumped pops up in most areas for Thu, and for areas north of Point Conception Wed night. Will keep the slight chance pops for Fri as is. This has the potential to be a fairly decent rain produced for so late in the season. There will be significant cooling across the area Thu, with temps well below normal. There may be some warming on Fri, but temps should still be below normal. A broad ridge building into the region on Sat should bring dry weather to the area and will likely lead to some warming. && .AVIATION...12/1121Z. At 1015Z, the marine inversion at KLAX was based at 1100 feet. The top of the inversion was 3700 feet with a temperature of 17 degrees Celsius. Overall, moderate to high confidence in 12Z TAF package. High confidence in Central Coast TAFs as well as valley and desert TAFs south of Point Conception. However only moderate confidence in coastal TAFs south of Point Conception as MVFR/IFR CIGs will be chaotic this morning. KLAX...Moderate confidence in 12Z TAF. There is a 30% chance that IFR CIGs will not develop around 13Z. For tonight, high confidence in return of stratus, but only moderate confidence in timing (could be +/- 3 hours of current 04Z forecast) and flight category (40% chance that CIGs will be at MVFR levels). KBUR...High confidence in 12Z TAF. There is a 10% chance of IFR CIGs after 08Z. && .MARINE...12/317 AM. For the Outer Waters, moderate to high confidence in current forecast. For PZZ670/673, high confidence in Small Craft Advisory (SCA) level winds this afternoon through Monday night with a 50% chance of SCA level winds on Tuesday. For PZZ676, there is a 30% chance of SCA level winds this afternoon through Tuesday northwest of San Nicolas Island. For the Inner Waters north of Point Sal, moderate confidence in current forecast. There is a 40% chance of SCA level winds each afternoon and evening today through Tuesday. For the Inner Waters south of Point Conception, high confidence in winds and seas remaining below SCA levels through Wednesday. On Thursday, there is a 50% chance of SCA level winds across western sections. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...Small Craft Advisory in effect from 3 PM this afternoon to 3 AM PDT Monday for zones 670-673. (See LAXMWWLOX). && .HAZARD POTENTIAL OUTLOOK (TUE-SAT). Strong rip currents are possible at area beaches Monday through Thursday. Another low pressure system will bring rain again on Thursday. && $$ PUBLIC...DB AVIATION...RAT MARINE...RAT SYNOPSIS...DB weather.gov/losangeles