Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000 FXUS66 KLOX 251236 AFDLOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 536 AM PDT Tue Apr 25 2017 .SYNOPSIS... Gusty northwest to north winds will likely continue through the work week for portions of Southwest California with weak to moderate offshore winds possible by this weekend. A gradual warming trend is expected for most areas through this weekend. && .SHORT TERM...(TDY-THU) There were plenty of low clouds on northern and interior mountain slopes, interior sections of SLO and SBA Counties, the Santa Ynez Valley and southern portions of the Central Coast. There could be a few light showers embedded in these clouds which could affect northern slopes this morning. Otherwise, areas of high clouds were drifting across the region early this morning. Any low clouds should clear by late morning, with partly cloudy skies this afternoon. Gusty nw to n winds continue across the Interstate-5 Corridor, southern Santa Barbara County through and below passes and canyons, the Santa Clarita Valley, and the Antelope Valley this morning, and wind advisories in all those areas look good. Expect advisory level northwest winds once again on the Central Coast this afternoon and evening. Locally gusty north winds will affect the San Fernando Valley, the valleys of VTU County and the Santa Monica mountains. An upper low was located in Wyoming with a trough extending southwestward into the Great Basin. There was broad cyclonic northwesterly flow across the forecast areas. Max temps should edge upward a few degrees today as heights and thicknesses rise slightly. Expect areas of low clouds on northern slopes and across interior sections of SLO and SBA County, and possibly across the Santa Ynez Valley and portions of the Central Coast tonight/Wed morning, with mostly clear skies elsewhere. Winds should decrease below advisory levels on the Central Coast this evening, across the Antelope Valley late tonight, and across southern SBA County and the Santa Clarita Valley Wed morning. However good N-S grads and decent nw winds aloft should make for windy conditions again Wed afternoon or evening into Thu morning. Wind advisories will likely be needed again on the Central Coast Wed afternoon, and southern SBA County and the Santa Clarita Valley Wed evening into Thu morning. Rising heights and thicknesses should lead to several degrees of warming in most areas on Wed. An upper low will drop into Montana Wed night and Thu. This will cause northwesterly flow aloft to increase across the region Thu, and any lull in the winds Thu morning should be brief. Additional wind advisories will likely be needed Thu. Max temps should be down a few degrees in most areas Thu. There may be a bit more in the way of stratus Wed night/Thu morning north of Pt Conception, and plenty of clouds are expected on northern slopes with a slight chance of showers there late Wed night into Thu morning .LONG TERM...(FRI-MON) The upper low will drop into Utah on Fri, with fairly strong nw flow aloft over the forecast area and continued steep N-S gradients. Gusty nw to n winds will continue to affect similar portions of the region on Fri. Do not expect too much in the way of stratus Thu night into Fri morning, especially south of Pt Conception. Max temps on Fri should be up a few degrees in most areas, mainly west of the mountains. Height and thicknesses will rise over the weekend as an upper ridge amplifies along the West Coast. Low level flow will turn more northeasterly by Sat, and though low level flow will weaken on Sunday, it will remain offshore, at least in the morning. Expect max temps to jump Sat on, especially west of the mountains, with highs likely in the lower 90s in the warmer valley locations. There may be a few degrees of cooling across the coastal plain on Sunday, especially near the coast, but it will be very warm elsewhere. As the upper high begins to break down on Monday, and flow turns onshore, expect cooling in coastal and valley areas, with little change in temps in the mtns and deserts. && .AVIATION...25/1200Z... At 1130Z, there was no marine layer inversion to speak of around KLAX early this morning. Overall, VFR conditions are expected for most areas away from the interior locations including the northern mountain slopes. There will be MVFR patchy cigs in the vicinity of KSBP and KSMX through 17z this morning as well as KPRB. Northerly winds should keep MVFR Cigs away from LA/VTU County Coastal and valley location over the next 24 hours. There is a 50% chance that MVFR cigs could develop around the Central Coast and interior areas later today through tonight. Bands of ACSL were streaming across the leeward side of the Tehachapi Mtns and could continue through this morning. There will be some UDDF across the mountains and LLWS is expected around KSBA later this afternoon, and KVNY through today. KLAX...moderate confidence in 12Z TAF. There is a 20% chance of MVFR CIGs 10z-15z Wed morning. High confidence in VFR conditions tonight. KBUR...high confidence in 12Z TAF. There is a 30% chance of LLWS/turbulence through 18z. && .MARINE...25/300 AM... For the Outer Waters, high confidence in current forecast. Strong northwest winds are anticipated to continue through the week. Currently, a Gale Warning is in effect through late Wednesday night. There is a 70% chance that Gale force winds will continue through Friday. For the Inner Waters, moderate confidence in current forecast. A Gale Warning has been issued once again valid for this afternoon for the inner waters south of Point Conception. Mainly affecting the western portions. Otherwise, Strong Small Craft Advisory (SCA) level winds are expected each afternoon/evening through Friday with a 30% chance of Gale force wind gusts developing.Due to strong winds throughout the waters, seas will be very choppy this week, making for hazardous boating conditions through the week. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...High Surf Advisory in effect until 9 AM PDT this morning for zones 34-35-40-41-87. (See LAXCFWLOX). Wind Advisory in effect from noon today to 9 PM PDT this evening for zones 34-35. (See LAXNPWLOX). Wind Advisory in effect until 9 AM PDT Wednesday for zones 39-52-88. (See LAXNPWLOX). Wind Advisory in effect until 9 AM PDT Thursday for zones 53-54. (See LAXNPWLOX). Wind Advisory in effect until 3 AM PDT Wednesday for zones 59-87. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday for zone 645. (See LAXMWWLOX). Gale Warning in effect from 3 PM this afternoon to 3 AM PDT Wednesday for zones 650-655. (See LAXMWWLOX). Gale Warning in effect until 3 AM PDT Thursday for zones 670-673-676. (See LAXMWWLOX). && .HAZARD POTENTIAL OUTLOOK...(THU-MON) Gusty north to northwest winds are expected across southern Santa Barbara County, the Central Coast, the I-5 corridor, and the Antelope Valley. Advisory level winds expected at times in these areas Thursday through early Friday, with local warning level gusts. Elevated surf is possible on the beaches Thursday night and Friday. Gusty northeast winds are possible across portions of Los Angeles and Ventura Counties Saturday, with well above normal temperatures expected. && $$ PUBLIC...DB AVIATION...CK MARINE...Kaplan SYNOPSIS...Munroe is the U.S. government's official web portal to all federal, state and local government web resources and services.