Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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588 FXUS66 KLOX 061113 AFDLOX Area Forecast Discussion...UPDATED National Weather Service Los Angeles/Oxnard CA 413 AM PDT Sun Oct 6 2024 Updated aviation section .SYNOPSIS...05/125 PM. An extended period of hot conditions will continue over the valleys and mountains into Tuesday, hottest today through Monday. Widespread cooling is expected Tuesday through Friday. Low clouds will continue to moderate the coastal areas, with dense fog and low visibilities at times. && .SHORT TERM (TDY-TUE)...06/329 AM. Today will be the warmest day of this three day (Sat to Mon) heat wave. 591 dam hgts will persist overhead, while at the sfc there will be 1 mb offshore trends from both the north and east. Look for about a degree of warming inland and 2 to 3 degrees in the vlys and the coasts. Max temps away from the coasts will be 10 to 20 degrees above normal and excessive heat warnings and advisories are in effect for much of the inland area. The offshore trends will not make much of an impact on the marine layer which will be slow to clear and will hug or cover many beaches. The marine layer appears to have deepened some and this has reduced the amount of dense fog to only a some patches. Monday will be fairly similar to today, but just a little cooler. The upper high will weaken and there will be about a mb of onshore trends both to the north and east. Look for 2 to 3 degrees of cooling everywhere save for the beaches which should warm a degree or two as the marine layer stratus deck will clear better and faster. Look for 4 to 8 degrees of cooling on Tuesday. A weak, saggy and dry trof will move over the area and will lower hgts to between 582 and 584 dam. The onshore flow in the afternoon will also increase a little bit. The coastal marine layer clouds will persist in the morning but with the capping inversion weakened by the cooler air aloft there should be good clearing in the afternoon. .LONG TERM (WED-SAT)...06/325 AM. Not too much excitement on tap for Wed and Thu next week. The area will be under a weak ridge with hgts only 588 dam. There will be near neutral flow in the N/S direction and lgt in the morning moderate in the afternoon onshore flow in the W/E direction. There will be a decent night through morning low cloud pattern that will cover the coasts and lower vlys, but there will be good clearing in the afternoon as the onshore flow is not too great and the inversion will not be too strong. Partly cloudy (mostly cloudy for SLO county) will develop Thursday as some mid level clouds advect in from the west. Max temps will fall 2 to 5 degrees on Wed and then another 1 or 2 degrees on Thu. Despite this cooling max temps away from the coasts will be 5 to 10 degrees above normal. A better trof will move into the area on Friday. It will bring 3 to 6 degrees of cooling to most of the area and this will finally bring most cst/vly temperatures to slightly below normal. Although there is a decent amount of disagreement between the deterministic and ensembles for the Saturday forecast it looks like there will be some ridging and offshore flow from the north. Skies should be clearer. The consensus max temp forecast brings 2 to 4 degrees of warming to the area which may be a little low if some of the higher hgt ridgier solutions come to fruition. && .AVIATION...06/1112Z. Due to a data outage, current marine layer depth and inversion height data is not available for KLAX. Moderate confidence in the current forecast for coastal terminals. High confidence in the current forecast for valley and desert terminals. Higher confidence exists in flight categories versus timing. LIFR conditions are likely at coastal terminals through at least 16Z, then conditions will likely improve at least one flight category between 16Z and 18Z. There is a low-to-moderate chance of VLIFR conditions through 15Z. There is a chance of scattering out as late as 23Z. An early return of LIFR conditions should be expected at coastal terminals. At valley and deserts, VFR conditions are expected through the period, except for a high chance of sub-VFR conditions at Los Angeles County valley terminals. KLAX...LIFR conditions will continue through at least 16Z. There is a 40 percent chance of VLIFR conditions through 15Z. Conditions could improve to the IFR category as soon as 16Z, or as late as 19Z. VFR conditions could develop as soon as 20Z or as late 22Z. LIFR to IFR conditions could spread in as early as 23Z or as late as 04Z. KBUR...There is a 50 percent of sub-VFR conditions through 15Z, otherwise VFR conditions are expected. && .MARINE...06/301 AM. Moderate-to-high confidence in the current forecast. Higher confidence exists in the forecast for seas. Less confidence in the current forecast for winds. Winds and seas will very likely remain below Small Craft Advisory (SCA) levels through Monday afternoon, except for a low-to- moderate (20-30 percent) chance of SCA level winds this afternoon and evening near Point Dume and Point Conception. For the waters southwest through northwest of the Channel Islands and the nearshore waters along the Central Coast, there is a high-to-likely (50-70 percent) chance of SCA level winds developing after Monday afternoon, especially during the afternoon and evening hours. The highest chances will be for the waters beyond 10 NM offshore and for the waters between Point Sal south to San Nicolas Island. There is a low-to-moderate (20-30 percent) chance of low end Gale Force winds Tuesday evening through Wednesday night. Inside the southern California bight, there is a low-to-moderate (20-40 percent) chance of SCA winds for the western portion of the Santa Barbara Channel each afternoon and evening from Tuesday through Friday. A shallow marine layer will continue to generate patchy dense fog across portions of the coastal waters through at least Monday morning, especially in the overnight through morning hours. Visibilities of one nautical mile or less can be expected. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Excessive Heat Warning remains in effect until 8 PM PDT Monday for zones 38-88-342>345-351>353-356>358-369>376-378>380-548. (See LAXNPWLOX). Heat Advisory remains in effect until 8 PM PDT Monday for zones 341-348. (See LAXNPWLOX). PZ...NONE. && $$ PUBLIC...Rorke AVIATION...Hall MARINE...Hall SYNOPSIS...RK/RS weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox