Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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578 FXUS66 KLOX 282321 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 421 PM PDT Sun Apr 28 2024 .SYNOPSIS...28/200 PM. Mostly clear skies and warmer temperatures will prevail across the region through this week, with just some coastal low clouds and fog possible at times night and morning hours early in the week and again late in the week. Gusty west to north winds will prevail over the mountains and deserts at least through Tuesday. && .SHORT TERM (TDY-WED)...28/153 PM. Mostly sunny skies covered the forecast area early this afternoon with little change expected thru the rest of the day. Gusty W to N winds to Advisory levels will affect portions of the forecast area at times this afternoon, including the SW SBA County mtns and coast, VTU County mtns, L.A. County mtns along the I-5 Corridor, and the western Antelope Vly foothills into the Antelope Vly. A Wind Advisory is in effect for these areas, where winds could gust to 45 to 50 mph. Breezy to gusty W-NW winds will also affect much of the coast and adjacent vlys thru this afternoon, strongest on the Central Coast where winds could approach Advisory levels at times. Some upper level ridging with H5 heights increasing to around 576 dam will help temps to warm up a few more degrees over yesterday and be near normal to a few degrees above normal for many areas away from the immediate coast this afternoon. Highs for the inland coast to the vlys and lower mtns should reach the 70s to around 80. Flat upper level ridging with H5 heights around 576 dam will persist over the area tonight thru Tue, then very weak upper level troffiness should move in by Wed with H5 heights falling slightly to around 573-574 dam. Marine layer low clouds and fog are expected to develop over the coastal waters tonight and move into the L.A. coast and portions of the Central Coast later tonight into Mon morning. Low clouds are expected to form in the Salinas River Vly in SLO County later tonight into Mon morning as well. Low clouds should affect the L.A. County coast night and morning hours Mon night thru Wed morning as offshore pressure gradients gradually increase and keep the low clouds away from other coastal areas. There should also be more low clouds late night and morning for the Salinas River Vly on Tue. Otherwise and elsewhere across SW CA, mostly clear skies will prevail tonight thru Wed. Strong and gusty NW to N winds are expected to continue tonight thru early Tue afternoon for the northern VTU County mtns, L.A. county mtns around the I-5 corridor as well as the western Antelope Vly foothills into the Antelope Vly, where gusts 45 to 55 mph will be possible at times. Gusty NW to N winds should also persist at times for the SBA County mtns and SW SBA County coast. Wind Advisories will be in effect for many of these areas during the period. Please see the latest Non-Precipitation Weather Message (LAXNPWLOX) for further details on the Wind Advisories. For the coast and vlys, breezy to gusty sub-Advisory level W to NW winds can be expected each afternoon, strongest along the Central Coast. Temps are forecast to be near normal to a few degrees above normal thru Wed, altho Tue should be the warmest day overall. Highs for the inland coast, vlys and lower mtns should reach the 70s to lower 80s each day. .LONG TERM (THU-SUN)...28/157 PM. The EC and GFS mean ensembles and deterministic are in generally good agreement Thu thru Sat with broad but generally weak upper level troffiness over the forecast area. By Sun, the deterministic models diverge quite a bit with the GFS forecasting a significant for early May storm system affecting the region with rain and high elevation mtn snow, while the EC has dry weather with rising H5 heights over the region. The GFS mean ensembles bring a 10%-20% chance of measurable rain to the area Sun, as only 4 out of 30 ensemble members show rain moving into the area at that time. For now we will go with a dry forecast for day 7. High pressure is fcst to move into NV on Thu morning and will set up offshore flow from both the N and E. A low end Santa Ana wind event will develop and keep any low clouds well offshore. Mostly clear skies are then expected to continue across the forecast area Thu night thru Sat, except for some night and morning low clouds and fog along the Central Coast Fri night into Sat morning. Increasing clouds are possible by Sun, and there may be some low clouds and fog along the coast into the adjacent vlys Sat night into Sun morning. With the offshore flow Thu and even some into Fri, temps are expected to be warmest for the week, with inland coast, vlys and lower mtns expected to top out in the mid 70s to mid 80s. A smattering of upper 80s is possible on Thu for the warmest vlys. It will turn cooler next weekend, with highs 2-6 deg below normal for many areas by Sun. && .AVIATION...28/2321Z. At 2215Z, the marine inversion at KLAX was based at 900 feet. The top of the inversion was 2300 feet with a temperature of 15 degrees Celsius. Overall, moderate to high confidence in 00Z TAF package. For KLAX and KLGB, only moderate confidence as there is a 50% chance that CIG/VSBY restrictions do not develop overnight. For KSMX, there is a 30% chance of IFR/LIFR conditions 09Z-17z. KLAX...Moderate confidence in 00Z TAF. There is a 50% chance that CIG/VSBY restrictions do not develop overnight. No significant easterly wind component is expected. KBUR...High confidence in 00Z TAF. && .MARINE...28/207 PM. A very long period of gale force winds is expected to continue thru at least Tue night for the outer waters. SCA conds are expected Wed thru Thu, with a 30% chance of gales persisting into Wed evening. In the inner waters N of Pt. Sal, SCA level winds are likely thru Tue night, especially in the afternoon/eve hours. There is a 50% chance of SCA conds during the afternoon/eve hours Wed/Thu. Seas are expected to be near SCA levels during the periods of weaker winds. There is a 25% chance of gale force winds during the afternoon/eve hours today thru Tue. In the SBA Channel, SCA level W-NW winds are expected across western portions during the afternoon thru late night hours today thru Wed. There is a 50% chance of SCA conds across the eastern portions late this afternoon and evening, and a 40% chance during the afternoon and evening hours Mon thru Tue. In the southern inner waters, there is a 40% chance of SCA level W to NW winds across northwestern portions, mainly from Anacapa Island to Malibu during the late afternoon thru late evening hours thru Tue. Widespread strong to gale force winds will keep dangerous sea conditions across much of the coastal waters (particularly the outer waters) thru the middle of the week, with short-period, steep, and choppy waves. There may be dangerous breaking waves near west-facing harbors. Mariners should plan accordingly. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory remains in effect until 3 PM PDT Monday for zones 349-351. (See LAXNPWLOX). Wind Advisory now in effect until 3 PM PDT Tuesday for zones 377-378-381-383. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Monday for zone 650. (See LAXMWWLOX). Gale Warning in effect until 3 AM PDT Wednesday for zones 670-673-676. (See LAXMWWLOX). && $$ PUBLIC...Sirard AVIATION...RAT MARINE...DB/RM SYNOPSIS...Sirard weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox