Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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086 FXUS66 KLOX 051315 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 615 AM PDT Sun May 5 2024 .SYNOPSIS...05/511 AM. A cold storm system will continue to exit the region today, leaving cooler temperatures across the region, isolated to scattered showers in the mountains, and gusty west to northwest across portions of the area. Zonal flow aloft will establish Monday and persist over the region into late week as an upper- level ridge builds into the eastern Pacific Ocean and an upper- level trough aloft digs into the Intermountain West and Great Basin. A warming trend will develop into late week. && .SHORT TERM (TDY-TUE)...05/511 AM. The latest radar mosaic shows light precipitation continuing to fall over Los Angeles County early this morning as a cold front moves over the region. Steady precipitation will exit the area towards dawn, and only isolated to scattered showers will become confined to the mountains late this morning. Skies should clear through the day, but a cold day for May is shaping up. There is a low to moderate chance of record cool high temperatures being set today, highest at a 40 percent chance for KPMD. The record daily cold maximum temperatures for KPMD is 61 degrees set on this calendar day in 1998. While coastal areas will be only about 3-8 degrees below normal for this time of year due to the typically persistent marine influence in May, the valleys, mountains, and desert are forecast to be 10-20 degrees below normal for today. The exception to this will be across southern Santa Barbara County where KSBA and the Santa Barbara area could be the warmest spot in the area due to compressional heating taking place with the northerly winds. A northwest surface pressure gradient will develop through today and gusty winds will increase across the area. The gradient will tighten through this afternoon and evening and increase the winds across the area. An ample west to northwest push will bring advisory levels winds to the coastal sections, portions of the coastal valleys, across the mountains, and down into the Antelope Valley. Wind advisories remain in effect for much of the Transverse Range and down into the southern Santa Barbara County through late tonight. A wind advisory for the remaining coastal sections and into the Santa Ynez Valley will go into effect at 10 am this morning. The wind advisory for the San Gabriel Mountains and eastern Antelope Valley foothills was just allowed to expire, but the advisory for the Antelope Valley and the adjacent western foothills was extended into this evening. If traveling across the area, be prepared for gusty cross winds, especially if driving along Highway 1 and 101, through the San Marcos Pass on Highway 154 and Tejon Pass on Interstate 5, and out across the high desert on Highway 14. Blowing dust may be a particular hazard at times west of Highway 14. Winds will start to diminish on Monday as the gradient relaxes. Generally, clearing skies are expected tonight through Monday, but there is a moderate chance of low clouds and fog returning to the Los Angeles County coastal area and southern Salinas Valley early Monday morning. A zonal flow pattern will develop aloft between Monday and Tuesday as ridging aloft will build into the eastern Pacific Ocean and an upper-level trough digs into Intermountain West. .LONG TERM (WED-SAT)...05/502 AM. A warming trend continues into at least Wednesday and possibly into late week. Forecast ensemble temperature means climbs throughout the week, but there is quite a bit of spread across the solutions with some uncertainties later in the week and next weekend. The spread becomes much more significant as forecast gets into Friday through next Sunday. The model solutions are struggling with how to handle the ridge to the west and the trough over the West, which could retrograde back as a cutoff low. The spread gets as large as 20-30 degrees for all locations across the region. For now, the forecast goes with NBM values. Gusty northerly winds are likely to persist through the Interstate 5 Corridor and across southern Santa Barbara County during the week. && .AVIATION...05/1312Z. At 12Z at KLAX, there was no marine layer nor inversion. Lingering moisture will keep skies partly to mostly cloudy this morning, especially away from the coast. Cigs will be mostly MVFR in coastal areas, and IFR or lower in the foothills/mtns. Expect skies to clear by afternoon, though some IFR-VLIFR cigs may linger in the foothills. Skies should be mostly clear tonight, except for possible stratus in the Salinas Vly and on the Central Coast with IFR-VLIFR conds, and possible MVFR cigs in coastal L.A. County. Gusty W to NW winds will affect much of the region thru this evening with areas of LLWS, turbulence and mdt UDDF. KLAX...Moderate confidence in TAF. There is a 20-30% chance of MVFR cigs thru 17Z and again 10Z-16Z Mon. Gusty west winds are expected later this morning thru this evening. There is a 20% chance of northerly cross winds to 12-18 kt from 02Z-07Z, and a a 20% chance of an E wind component of 7-8 kt 10Z-17Z Mon. KBUR...Moderate confidence in TAF. There is a 20-30% chance of MVFR cigs thru 17Z and again 10Z-16Z Mon. There is a 30% chance of NW wind gusts to 25 kt from 16Z-02Z Mon. && .MARINE...05/600 AM. In the Outer Waters, moderate to high confidence in the forecast. In the southern two zones (PZZ673/676), expect winds to increase to gales (80% chance) this afternoon, then continue thru late tonight. Otherwise and elsewhere, SCA level winds (and seas at times) are expected thru Wed night, with a 40% chance of SCA conds Thu. There is a 50% chance of gales Tue afternoon into Tue night. For the Inner Waters N of Pt. Sal, moderate to high confidence in the forecast. Thru Wed night, winds are expected to reach SCA levels during the afternoon/eve hours. Seas may remain at or above SCA levels Mon night thru Wed morning, even when the winds decrease. In the Inner Waters S of Pt. Conception, moderate confidence in the forecast. Expect SCA level winds to increase to gales this afternoon into tonight across the SBA Channel, (70-80% chance), and from Anacapa Island to Malibu (60% chance). Elsewhere, SCA conds are expected thru late tonight. SCA conds are likely (70% chance) during the late afternoon thru late night hours Mon and Tue, with a 30-40% chance of SCA conds during these times in the eastern portion of the SBA Channel and western portions of the southern inner waters. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory remains in effect from 10 AM this morning to 9 PM PDT this evening for zones 87-340-341-346>348-354-355-362-366. (See LAXNPWLOX). Wind Advisory remains in effect until 3 AM PDT Monday for zones 349>353-376>378. (See LAXNPWLOX). Wind Advisory remains in effect until 9 PM PDT this evening for zones 381-383. (See LAXNPWLOX). PZ...Small Craft Advisory in effect from 3 PM this afternoon to 9 PM PDT this evening for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 3 PM PDT this afternoon for zones 650-655-673-676. (See LAXMWWLOX). Gale Warning in effect from 3 PM this afternoon to 3 AM PDT Monday for zones 650-655-673-676. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Monday for zone 670. (See LAXMWWLOX). && $$ PUBLIC...Hall AVIATION...DB MARINE...DB SYNOPSIS...Hall weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox