Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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653 FXUS66 KLOX 251019 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 319 AM PDT Wed Sep 25 2024 .SYNOPSIS...24/633 PM. Low clouds and fog will continue across coastal areas through the week with some afternoon clearing and below normal temperatures. Valley temperatures are expected to be at or below normal for the remainder of the week, while the far interior areas will remain above normal. Otherwise, a quiet weather pattern will continue. && .SHORT TERM (TDY-FRI)...25/301 AM. Quiet early July like weather will continue through the short term. The area will be in between a upper level high to the east and a large east pac trof to the west with weak SW flow over Srn CA. On Friday the upper high exerts itself and pushes into the state from the east. 584 dams hgts today will rise to 590 dam by Friday. At the sfc gradients will slowly trend offshore as the high pressure moves closer. Currently the marine layer is 1600 ft deep and marine layer stratus covers all of the coasts and most of the vlys including the Santa Clarita. It will be another day of slow clearing with no clearing likely at more than a few beaches. Today`s temps will not change much across the coasts (the SBA south cst will be the exception as a N to S offshore push will bring some warming). The Vlys and interior will cool noticeably with 3 to 6 degrees of cooling like and up to 10 degrees in the Paso Robles area. The increasing hgts and offshore trends will decrease the marine layer stratus coverage a little each morning Thu and Fri. Clearing will be quicker and more complete each day as well. Max temps will raise a degree or two on Thu and 1 to 3 degrees on Friday. As mentioned at the top of the discussion this pattern will produce a temperature distribution that resembles July with the max temps across the coasts and lower vlys 3 to 6 degrees blo normal and the interior running 3 to 6 degrees above normal. .LONG TERM (SAT-TUE)...25/318 AM. Decent mdl agreement for the weekend. A weak trof is fcst to swing into the state and knock the upper high down to the SE. Hgts will fall to 584 or 585 dam. More importantly onshore flow to the east will increase to 7 or 8 mb. This surge in onshore flow coupled with the lowering hgts will bring 2 to 4 degrees of cooling to the area. The increased onshore flow will also great gusty conditions across the LA mtns and the Antelope Vly. Not much change on Sunday. Morning stratus will cover most of the coasts, otherwise skies will be sunny. Max temps will change little from Saturday and will be 3 to 6 degrees blo normals across the csts/vlys and 4 to 8 degrees above normal inland. The mdls diverge and the ensemble spread increases for the forecast early next week. Despite the lower confidence in the exact forecast there is good confidence that the benign weather will continue. Most likely scenario calls for an upper high and increasing hgts leading to a two day warming trend. Max temps on Tuesday could reach into the upper 90s in the warmer vlys. && .AVIATION...25/0048Z. At 0030Z at KLAX, the marine layer was 1500 ft deep. The top of the inversion was near 2200 ft with a temperature of 28 deg C. High confidence in IFR or lower cigs/vsbys for coastal TAFs with low confidence in timing of return to VFR with a 10-30% (highest nearest the coast) chance that of brief or no return to VFR conds occur. Moderate confidence in valley TAFS (KBUR/KVNY/KPRB) with a 10-20% chance VFR conds prevail for KBUR/KVNY and a 20% chance of IFR conds KPRB (10-18Z). High confidence in KPMD and KWJF TAFs. KLAX...Moderate confidence in TAF. There is a 10% chance for VV002 cigs and/or vsbys 1/2SM or lower between 04Z and 15Z. However, there is also a 20% chance for cigs to remain OVC005 or higher thru the period. High confidence in no significant east wind component. KBUR...Moderate confidence in TAF. There is 10% chance VFR conds prevail thru the period. && .MARINE...24/858 PM. A low end Small Craft Advisory has been issued for the southern Inner Waters and southern Outer Waters and is in effect late Wednesday afternoon through early evening. For the Outer Waters (Central Coast south to San Nicolas Island), moderate to high confidence in the forceast. High confidence in the northern zone (10 to 60 NM off the Central Coast) remaining below Small Craft Advisory (SCA) level thru Thursday, then there is a 40-60% chance of SCA winds Thurs afternoon thru evening. In the two Southern Zones (Pt Sal to San Nicolas Islands), moderate confidence in conditions remaining sub advisory thru Wednesday afternoon. Then there is a 40-60% chance of SCA level winds form Pt Conception to San Nicolas Island in the afternoon thru evening Wednesday and Thurs. Then, moderate confidence in the Outer Waters remaining sub advisory Friday thru late Saturday, then increasing to SCA level thru late Sunday. For the Inner Waters along the Central Coast, moderate to high confidence in conditions remaining sub advisory thru the period, with highest chances (20-40%) of SCA conditions Thurs afternoon thru evening and late Sat thru late Sun. For the Inner Waters south of Pt Conception, moderate confidence in winds and seas remaining below SCA level thru Wednesday morning. Moderate confidence (50-70% chance) in SCA level winds in Santa Barbara Channel and from Anacapa Island to Pt Dume and the San Pedro Channel Wednesday late afternoon thru early evening. Then, moderate confidence in winds remaining sub advisory thru Sunday, and increasing Sunday afternoon thru evening in the Western Portion of the Santa Barbara Channel. A shallow marine layer will bring at least patchy dense fog thru Wednesday, especially in the afternoon thru evening hours. Please refer to our marine weather statement for more information. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...Small Craft Advisory in effect from 2 PM this afternoon to 9 PM PDT this evening for zones 650-655-676. (See LAXMWWLOX). && $$ PUBLIC...Rorke AVIATION...Munroe/Lewis MARINE...Lewis/Munroe SYNOPSIS...MW/Smith weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox