Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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593 FXUS66 KLOX 151133 AFDLOX Area Forecast Discussion...UPDATED National Weather Service Los Angeles/Oxnard CA 433 AM PDT Thu Aug 15 2024 .SYNOPSIS...14/800 PM. Daytime highs will be near normal for most areas through the weekend, followed by a warm up early next week. Patchy overnight into morning low clouds and fog will impact coastal areas at times. Gusty winds are likely across Southwest Santa Barbara County and the Antelope Valley during the evening into overnight hours through Thursday night. && .SHORT TERM (TDY-SAT)...15/237 AM. Three days of uneventful weather on tap for Srn CA. At the upper levels a very warm upper high will slide over the CA/Mexico border and into New Mexico today and Friday. On Saturday a cool (at least for mid August) will approach the CA/OR border and this will push hgts down. At the sfc there will be weak to moderate onshore flow to the east and weak occasionally offshore flow in the N/S direction. Today and Friday will be very similar days. The lack of an eddy or any other source of low level lift will really suppress marine layer cloud formation and skies will be mostly clear over the next 48 hours. The only exception will be the western portion of SBA county where there will be some morning low clouds. The SW tip of LA county has a chc of some low clouds as well. Almost all areas will see 3 to 5 degrees of warming today with the only the LA/VTA county coasts excluded. Most of the vlys will be a few degrees above normal today while the coasts and the interior will be a few degrees blo normal. One notable exception will be the SBA south coast where a N to S offshore push across the county will boost temps 5 to 10 degrees above normal. Look for another 2 to 4 degrees of warming on Friday everywhere except the SBA county south coast and the VTA county cst/vlys where a little better W to E onshore push will bring a few degrees of cooling. It will be noticeably cooler on Saturday. The approaching upper low will lower hgts. In addition the lower hgts and better onshore flow will bring more marine stratus to the coasts in the morning. The lower hgts, deeper marine layer and stronger onshore flow will all conspire to lower max temps 2 to 5 degrees. Most max temps will come in 2 to 4 degrees blo normal. The N to S offshore push across SBA county produced low end advisory level gusts last evening and will likely produce another round of advisory level Sundowner gusts tonight into early Friday morning. The strongest gusts will occur near Gaviota. The upper level flow pattern is not conducive to monsoonal flow and the threat of afternoon convection is low - well under 10 percent. .LONG TERM (SUN-WED)...15/312 AM. Mdls and ensembles have come into better agreement for the xtnd fcst. During the period big 598 dam upper high will slow push to the west moving from the TX panhandle to western NM. Hgts over Srn CA will climb from 590 dam to 594 dam. The sfc pressure pattern will not change much during the period with weak to moderate onshore flow to the east and weak onshore flow to the N in the afternoon followed by weak offshore flow to the S in the early mornings. There will be little in the way of marine layer clouds as the extra high hgts will keep the marine layer smooshed to under 800 ft. In addition there will be not be any low level lifting mechanisms that would help to generate clouds. Max temps will be the main talking point of the xtnd fcst with a 4 day warming trend on tap. Max temps will climb 1 to 3 degrees per day Sun through Tue with perhaps a degree or two of additional warming on Wed. By Wed the only 70s will be right at the beaches with 80s and lower 90s across the rest of the coasts. The vlys will see max temps in the 90s to 102 degrees. There will be plenty of triple digit heat across the far interior and lower mtn elevations as well. These max temps are 3 to 6 degrees above normal. While rather warm these temps are a few degrees below critical heat advisory thresholds. The flow pattern on Tue and Wed is mildly conducive to monsoon flow. Only a few ensembles pick up on any flow and right now the chc of afternoon convection remains less than 10 percent. Still days 6 and 7 are a ways off and this fcst could change. && .AVIATION...15/1132Z. At 1034Z at KLAX, the marine layer was 400 ft deep. The top of the inversion was 3000 ft with a temperature of 24 Celsius. Very high confidence in VFR conds for KPRB, KBUR, KVNY, KPMD, KWJF. Moderate to high confidence in all other TAFs, except KLGB and KSMX where there is low confidence through 16Z. There is a 50% chance that VFR conds at KSMX prevail through the period, and a 40% of VFR conds at KLGB. There is a 30% chance of cigs at KSBP through 16Z. Moderate confidence in any ceilings being LIFR- IFR at KSBP and KSMX, and IFR- MVFR at KLGB. Good confidence in cigs clearing by 16Z. KLAX...Moderate to high confidence in TAF. There is a 20% chance of OVC008-012 cigs through 16Z Thurs, and 09Z-16Z Fri. Good confidence that any east wind component will remain under 5 kt. KBUR...High confidence in VFR TAF. && .MARINE...15/314 AM. For the offshore waters from the Central Coast to San Nicolas Island (the outer waters), Gale force wind gusts are expected through late tonight, with the strongest winds occuring during the late afternoon through late evening hours. High confidence of SCA level winds following the gales through at least the weekend. For the nearshore waters of the Central Coast, moderate confidence in SCA level winds and/or steep seas through today, strongest in the afternoon and evening hours. Chances of SCA lower Friday through the weekend. For the Santa Barbara Channel, high confidence in SCA levels winds over the far western portion this afternoon and evening, with a 50% chance of SCA winds extending across the entire western half of the channel. Moderate confidence that the eastern portion will stay under SCA levels. Over the weekend, there is a 40% chance of SCA level winds over the western half of the channel during the afternoon and evening hours. For the waters off of Los Angeles and Orange Counties, other than local gusts to 20 to 25 knots in the San Pedro Channel, high confidence in conditions staying under SCA levels. High confidence in building short period seas through Friday morning nearly everywhere, including the nearshore waters. With a shallow marine layer, high confidence in dense fog with visibilities under 1 mile effecting the Central Coast waters through the week. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...Small Craft Advisory in effect until 5 AM PDT Friday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect from noon today to 3 AM PDT Friday for zone 650. (See LAXMWWLOX). Gale Warning in effect until 3 AM PDT Friday for zones 670-673-676. (See LAXMWWLOX). && $$ PUBLIC...Rorke AVIATION...Lund MARINE...RK/Lewis/Lund SYNOPSIS...RS/KL weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox