Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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628 FXUS66 KLOX 071154 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 454 AM PDT Sun Jul 7 2024 .SYNOPSIS...06/214 PM. A long-lasting and extreme heatwave will continue across the region, and especially the interior, through much of next week. There is a high risk for dangerous heat illness and fast-growing fires. High temperatures will reach 105 to 115 across interior valleys, mountains and deserts. Dense fog may develop across some beaches during the night and morning hours. && .SHORT TERM (TDY-TUE)...07/437 AM. Strong upper high level high pressure will linger across the region today. Slight height falls may result in a degree or two of cooling in the mountains and desert. Some cooling is also possible in coastal areas, due to slow clearing of marine layer clouds today. Despite slight cooling, Excessive Heat Warnings are still necessary due to temperatures of 95-105 degrees across the coastal slopes and Santa Clarita Valley, and 105-115 degrees across the far interior areas including the Antelope Valley. Expecting low clouds this morning to burn off, but there is a good chance that the clouds will hug the coast through the day and maybe not even clear at some of the beaches. Monday should again be very similar to today, if not a little bit warmer as the onshore flow starts to weaken. Tuesday will once again warm up as the gradients will weaken even more, allowing the valleys to warm up - possibly to heat advisory levels. Sundowners across the Santa Barbara South coast will start Monday night resulting in winds close to, but likely just sub- advisory levels. However, Tuesday night the offshore gradients will increase and likely result in advisory level winds across the SBA South Coast. .LONG TERM (WED-SAT)...06/213 PM. The GFS and EC are in generally good agreement in the extended period. The large and strong upper level high will slowly push into srn NV for Wed then linger in this general area into Thu. The upper level hi will then move more into the Four Corners region for Fri and Sat. Srn CA will be under the western and southwestern periphery of the upper level hi thru Fri, then a weak upper level trof will develop along the CA coast for Sat. The Central Coast is expected to have night and morning low clouds and fog thru the period, with varying amounts of low clouds and fog S of Point Conception, primarily on the L.A./VTU County coast at times as a northerly flow over the Santa Ynez range should keep the SBA County S coast free of the low clouds. Low clouds may persist at some of the Central Coast beaches each afternoon as well. Otherwise, mostly clear skies are expected for Wed thru Sat. Excessive heat is expected to continue Wed and Thu, especially for the interior vlys to the mtns and deserts, and existing Excessive heat Warnings which run thru Wed for these areas may need to be extended into Thu. It also looks like Heat Advisories or even Excessive Heat Warnings may be needed for the vlys and Santa Ynez Mtns Wed and Thu as temps heat up due to to weaker onshore flow. Temps should cool down enough for Fri and Sat due to stronger onshore flow to the N and E that the only areas that may need heat products would be the L.A. County mtns and deserts. Even with cooler temps for the coast and vlys, it will still be several degrees above normal each day. && .AVIATION...07/0653Z. At 06Z at KLAX, the marine layer was 900 feet deep. The top of the inversion was at 4200 feet with a temperature of 33 deg C. High confidence in CAVU TAFs for KPRB, KPMD, and KWJF. Low confidence in all other TAFs. Flight category changes may be off by +/- 2 hours. LIFR conditions possible starting after 08Z at KSMO (20%), KLAX (30%), KLGB (20%). VLIFR conditions possible 08Z-16Z at KSBP (20%), KSMX (40%), KSBA (40%), KOXR (40%), KCMA (30%), KBUR (10%), and KVNY (10%) due to rapid shallowiing of the marine layer. Cigs/vsbys are likely (80-90%) to improve to MVFR-VFR conditions 18-22Z. There is a chance that KOXR/KSBA/KSMX (30-50%) have limited to no clearing. Nearby fires may lead to periods of MVFR/VFR smoke at terminal, especially KSBA and north. KLAX...Moderate confidence in the 06Z TAF. Timing of flight cat changes could be off by +/- 2 hours. There is a chance (30%) of 1/2SM and BKN002-BKN004 conditions thru 14Z Sun. Good confidence in any east wind component remaining under 5 kts. KBUR...Low confidence in the 06Z TAF. Cig/vis arrivals could be off by +/- 2 hours. There is 10% chance of 1/4SM and BKN002 conds 10Z-14Z Sun. There is a 40% chance of no cig/vsby arrival. && .MARINE...06/935 PM. For the Outer Waters, expecting winds to generally remain below SCA levels tonight and Sun morning. However, cannot rule out local gusts near SCA levels along the Central Coast and near Point Conception. Winds are expected to decrease overnight tonight. There is a 30% chance for SCA level winds Sunday afternoon and evening near Point Conception. By Monday, chances for SCA winds increase to around 40%, with more widespread winds through the outer waters through Tuesday night. Could see SCA winds Wednesday through Thursday as well. In the inner waters N of Pt. Sal, there is a 30% chance of SCA level winds during the afternoon/evening hours Mon and Tue, otherwise SCA conds are not expected thru Wed night. In the inner waters south of Pt Conception, SCA conditions are not expected thru Thu. However, there is a 20% chance for SCA level winds over far western portions of the Santa Barbara Channel Sunday evening. Then there is a 30% chance of SCA winds during the afternoon/evening hours Tue thru Thu in western portions of the Santa Barbara Channel, mainly from Santa Cruz Island to the SBA County south coast from Pt. Conception to Gaviota to Refugio State Beach. Areas of dense fog will continue to affect the coastal waters through Sun morning. Please reference the Marine Weather Statement for additional information. && .BEACHES...06/958 PM. A moderate southerly swell will continue to affect the Southern California coastal waters through Sunday, with a 14-16-second period this weekend. While surf is not expected to be particularly high, surf heights of up to 4 to 6 feet are anticipated at beaches exposed to southerly swell, especially the LA and Ventura County beaches. Significant wave energy with the long-period swell will combine with the elevated surf to create dangerous conditions at area beaches, with powerful and dangerous rip currents expected. This is especially the case for the south-facing beaches of LA and Ventura Counties. A Beach Hazards Statement is in effect through Sunday evening to address these concerns. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Excessive Heat Warning remains in effect until 9 PM PDT Wednesday for zones 38-343>345-353-376>379-381>383. (See LAXNPWLOX). Excessive Heat Warning remains in effect until 9 PM PDT this evening for zones 88-351-352-375-380. (See LAXNPWLOX). Beach Hazards Statement in effect through this evening for zones 354-362-366. (See LAXCFWLOX). Red Flag Warning in effect until 6 AM PDT Monday for zones 378-381. (See LAXRFWLOX). PZ...NONE. && $$ PUBLIC...Lund/DB AVIATION...Lewis/KL MARINE...Phillips/DB BEACHES...LP/DB SYNOPSIS...Sirard weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox