Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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619 FXUS66 KLOX 081118 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 418 AM PDT Wed May 8 2024 .SYNOPSIS...08/331 AM. Gusty northeast winds will affect portions of Los Angeles and Ventura Counties this morning and some warming is expected today. Otherwise, a quiet weather pattern is expected through early next week, with dry conditions. Night through morning low clouds should become more extensive late in the weekend and early next week. Mostly minor day to day changes in temperatures are expected through Sunday, with some cooling possible Monday and Tuesday. && .SHORT TERM (TDY-FRI)...08/418 AM. Gusty northwest to north winds have dropped below advisory levels in most areas, so the Wind Advisory was allowed to expire. Low level flow has begun to turn northeasterly, and some gusty NE winds will develop in the mountains of Ventura and L.A. County, the northern/western valleys of L.A. County and VTU County, and coastal sections of VTU County. There could be a few advisory level gusts in the more wind-prone locations, but in general, expect winds to remain below advisory levels this m morning. A pronounced eddy circulation has developed across the inner coastal waters. This has caused low clouds to spread northward form the L.A. County coast into the San Gabriel Valley and eastern portions of the San Fernando Valley, and clouds may become a bit more widespread in the San Fernando Valley by daybreak. Patchy low clouds and fog have also developed across southern portions of the Central Coast. Skies are expected to clear by mid morning. While heights and thicknesses will be a bit lower across the region than they were on Tue, there should actually be some warming, especially west of the mountains, thank to offshore flow and warming at 950 mb. The upper pattern featured a large upper low in the Great Plains extending southwestward into Utah early this morning. A strong rotating around the western periphery of this upper low is cause a new upper low to form over Utah late tonight and Thu, with troughing, and broad cyclonic flow aloft extending into the forecast area. The high resolution models have really keyed in on a good eddy circulation tonight, with rather strong SE flow spreading thru the Santa Barbara Channel tonight. By Thu morning, this will evolve into a full blown southerly surge as southerly winds at the surface round Pt. Conception and spread northward into and off the Central Coast. Expect more widespread low clouds/fog in coastal areas and in the the lower valleys tonight/Thu morning. The question is whether or not the eddy circulation tonight shifts westward too much, and actually pulls clouds off the coast of L.A. County. But in general, clouds should be more widespread tonight/Thu morning, with clearing expected in most areas by late Thu morning. There will be a fair amount of cooling at 950 mb due to the southeasterly flow, so expect several degrees of cooling in most areas west of the mountains. The exception may be across the Santa Ynez Valley and southern portions of the Central Coast, where southerly flow will downslope, producing some warming. The upper low will drift southwestward into southern Nevada Thu night/Fri, but it will weaken, and heights will actually rise across the area. Expect night thru morning low clouds in coastal and some valley areas Thu night/Fri morning. Max temps should be up a few degrees in most areas Fri, at least away from the coast. .LONG TERM (SAT-TUE)...07/208 PM. Ensemble models have a range of outcomes over the weekend, concerning where the wobbling upper level low wants to go. The most likely outcome is for steady increase of onshore flow bringing more cool coastal clouds and gusty onshore winds over the interior. To what magnitude however is still on the table. The first half of next week, looks fairly benign, except for likely continued strengthening of the onshore flow over the mountains and interior, with further expansion of low clouds on the coastal side. There are some indications of some warming for the second half of next week with high pressure building in. && .AVIATION...08/0031Z. At 2300Z at KLAX, the marine layer was 1500 ft deep, with an inversion top at 4300 ft and a temperature of 16 C. Moderate confidence in the 00Z TAF package. There is a 30% chance of no CIGs developing at KPRB, and a 30% of no CIGs for sites KLAX/KLGB/KSMO. There is also a 20% chance of CIGs forming at KBUR and KVNY, most likely in the IFR to low MVFR category if they do form. The timing of flight cat changes could be off by +/- 2 hours. For KPMD and KWJF, there is a 40% chance of MVFR VSBYs in blowing dust through 04Z. KLAX...Moderate confidence in the 00Z TAF. Timing of cig changes may be off by +/- 2 hours, and there is a 20-30% chance of no cigs developing at all. An easterly wind component up to 8 knots is expected between 09Z to 16Z, with just a 10% chance of the east wind component reaching 10 kts during this time. KBUR...Moderate to high confidence in the 00Z TAF. There is a 20% chance of IFR to low MVFR CIGs forming between 12Z to 16Z. && .MARINE...08/104 AM. For the Outer Waters, high confidence in the current forecast. Today through tonight, a combination of Small Craft Advisory (SCA0 level winds and seas are expected. For Thursday through Sunday, winds and seas will remain below SCA levels. For the Inner Waters north of Point Sal, moderate to high confidence in the current forecast. For today, there is a 30% chance of SCA level winds this afternoon and evening. For tonight through Sunday, high confidence in winds and seas remaining below SCA levels. For the Inner Waters south of Point Conception, high confidence in the current forecast. Today through Sunday, winds and seas will remain below SCA levels. For tonight and Thursday morning, southeasterly wind gusts of 10 to 15 knots will be possible. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...High Surf Advisory in effect until 9 AM PDT Thursday for zones 340-346. (See LAXCFWLOX). Beach Hazards Statement in effect through this evening for zone 354. (See LAXCFWLOX). PZ...Small Craft Advisory in effect until 3 AM PDT Thursday for zones 670-673-676. (See LAXMWWLOX). && $$ PUBLIC...DB/Kittell AVIATION...Smith MARINE...RAT SYNOPSIS...DB weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox