Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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120 FXUS66 KLOX 291240 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 540 AM PDT Wed May 29 2024 .SYNOPSIS...29/238 AM. Increasing northerly flow this week is expected to cause earlier and more complete clearing of the marine layer, leading to slightly warmer temperatures and more afternoon sunshine. Breezy northerly winds will develop across southern Santa Barbara County and some interior areas each afternoon and evening. && .SHORT TERM (TDY-FRI)...29/318 AM. Three very similar days on tap across Srn CA. Slightly cyclonic NW flow will prevail overhead. At the sfc there will be moderate to strong onshore flow from the W to the E. There will be weak offshore from the north this morning and Thursday morning from the N to the S. Strong NW winds have developed over the outer waters and although they will diminish some later Thursday and into Friday will remain fairly strong. The northwest flow has cleared the low clouds out from the outer waters as well as the SLO county portion of the Central Coast. Low clouds do cover the western portion of SBA county as they back build from the Santa Ynez Vly. Meanwhile south of Pt Conception a weak eddy has brought low clouds to the coasts and vlys. The strong W to E onshore flow will bring slower than normal clearing and some west facing beaches will likely not clear at all. Max temps will not chance much just a little warming across the mtns. The csts and vlys will remain about 6 degrees blo normal. The interior will remain a few degrees above normal. The strong push to the east along with some NW upper level support will bring advisory level gusts of 45 to 50 mph to the I-5 corridor and the western Antelope Vly foothills. At one time the SW corner of SBA county looked like it would also have advisory level gusts but the latest hi rez ensemble guidance only shows a brief 2 hour window of advisory level gusts. Look for even less low clouds tonight and Thursday as the N flow continues. In fact it looks like all of SBA and SLO counties will be clear. While there will be low clouds across VTA/LA counties the north push will limit vly penetration. The increased north flow and slightly higher hgts will also bring 2 to 4 degrees of warming to almost all of the area. The N/S gradient reverses on Friday and becomes onshore. A southerly stratus surge looks likely. Low clouds will also move back into most of the vlys. The strong W to E gradient will continue and clearing will be slower and some beaches will not clear at all. Max temps will fall by a few degrees. It will be breezy across the interior in the afternoon but likely below advisory levels. .LONG TERM (SAT-TUE)...29/338 AM. Look for a cooler and cloudier weekend as a sharper trof moves over the state. The trof may produce some morning drizzle as the marine layer lifts. Clearing may be limited across the coasts. Max temps will cool by 1 to 2 degrees each day over much of the area. Max temps across the csts vlys will end up 5 to 10 degrees blo normal in the upper 60s and 70s. The ensembles are not in the best of agreement for the days 6 and 7 period but the preponderance of solutions do favor some sort of ridging. The moderate to strong onshore flow will continue but the higher hgts may squeeze the marine layer down low enough to keep some vlys clear. Its likely that the stronger marine inversion coupled with the strong afternoon onshore flow will limit clearing at the beaches and a few miles inland. Max temps will war each day everywhere except the near shore area. Inland areas will warm the most with mid 90s likely in the Antelope Vly and an out side chc of the years first triple digit reading next Wednesday. && .AVIATION...29/1213Z. At 11Z at KLAX, the marine layer was 1800 ft deep. The top of the inversion was at 3200 feet with a temperature of 17 C. High confidence in desert TAFs, with clear skies and gusty winds this afternoon and evening. Low clouds were affect all coastal areas except for far southwestern SBA County and the northern SLO County coast. Low clouds have also pushed into the valleys, except for the interior valleys of SLO and SBA Counties and parts of the Santa Clarita Valley. the most valley locations will push into the Santa Ynez and San Gabriel Valleys by midnight, and the San Fernando Valley and the valleys of VTU Counties later tonight. Conditions were mostly IFR to LIFR, except locally VLIFR in the valleys/foothills and on portions of the Central Coast. Cigs have risen to low MVFR levels across coastal L.A. County. Skies should clear by mid to late morning in the valleys and by early afternoon across most of the coastal plain. However, cigs may linger at the beaches of L.A./VTU Counties thru the day. Expect clouds to return to coastal areas this evening, then into the lower valleys tonight. Conds will be mostly IFR to LIFR tonight. KLAX...Moderate confidence in TAF. There is a 20% chance that cigs will not rise into the MVFR category until 15Z-16Z. There is 20% chance that MVFR cigs will persist all day. There is a 20% chance of an east wind component of 7-8 kt thru 16Z. KBUR...Moderate confidence in TAF. There is a 20% chance that cigs will not scatter out until 19Z, but may rise into the MVFR category. There is a 20-30% chance of IFR to LIFR cigs after 09Z tonight. && .MARINE...29/539 AM. Moderate confidence in forecast. In the outer waters, winds are expected to increase to low-end gales today, mainly well off the coast, and linger into tonight. There is a 30% chance that winds will remain mostly in the Small Craft Advisory (SCA) category. SCA level winds/seas are likely (70-80% chance) Thu into Thu night. Conds are expected to be below SCA levels late Thu night/Fri, though seas may be close. SCA level conds are likely (60-70% chance) Fri night thru Sun. In the inner waters N of Pt. Sal, SCA winds are expected (80% chance) this afternoon/eve, and are likely (70% chance) Thu afternoon/eve. SCA conds are not expected late Thu evening thru early Sat. There is 40% chance of SCA level winds in the afternoon/eve hours Sat/Sun. In the inner waters S of Pt. Sal, SCA winds are likely (70% chance) in W portions of the SBA Channel this afternoon/eve, and a 40% chance Sun afternoon/eve. Otherwise, SCA conds are not expected. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory in effect from 6 PM this evening to 3 AM PDT Thursday for zones 378-381. (See LAXNPWLOX). PZ...Small Craft Advisory in effect from 3 PM this afternoon to 9 PM PDT this evening for zones 645-650. (See LAXMWWLOX). Gale Warning in effect until 3 AM PDT Thursday for zones 670-673-676. (See LAXMWWLOX). && $$ PUBLIC...Rorke AVIATION...DB MARINE...DB SYNOPSIS...MW/Smith weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox