Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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142 FXUS66 KLOX 071607 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 907 AM PDT Tue May 7 2024 .SYNOPSIS...07/441 AM. Dry weather is expected through early next week. There will be areas of gusty northwest to north winds through tonight. After slight cooling today, some warming is expected Wed. Mostly benign weather is expected Thursday through early next week, with areas of night through morning low clouds, mainly in coastal areas. Expect mostly minor day to day changes in maximum temperatures Friday and Saturday, with some cooling possible Sunday and Monday. && .SHORT TERM (TDY-THU)...07/907 AM. ***UPDATE*** Generally sunny skies this morning will continue this afternoon. Northwest winds will continue through this evening, resulting in Wind Advisory gusts over the most wind-prone areas (like the northern mountains, Santa Ynez Range and the Antelope Valley). Gusts are generally in the 25 to 40 mph range in those areas, but should increase another 10 mph this afternoon and evening. The current forecast is in good shape with no updates needed. ***From Previous Discussion*** Except for patchy low clouds and fog across the southern Central Coast and Santa Ynez Valley, and portions of interior SLO County, skies were clear across the region. Any low clouds should dissipate by mid morning. Otherwise, today will be a mostly sunny day, with just some high clouds from time to time. Broad, weakly cyclonic northwesterly flow aloft will continue across the region today. Heights will actually drop a bit today as a vort drops south thru the Great Basin. The WRF shows a bit of cooling at 950 mb. Overall, changes are minimal, so do not expect too much change in max temps from those on Mon. Gusty north winds continued across the I-5 Corridor and the mtns of northern VTU County, and a Wind Advisory remains in effect thru mid morning. This looks fine, since winds will be diminishing and should remain below advisory levels much of the day. However, sharpening N-S gradients, increasing flow aloft, and subsidence support another round of gusty northwest to north winds late this afternoon/early this evening thru late tonight. Winds should reach advisory levels late this afternoon across southwestern SBA County, thru the I-5 Corridor, in the western foothills of the Antelope Valley, and in far western portions of the Antelope Valley itself. During the early evening hours. advisory level winds should also develop in the mountains of VTU County, the interior mountains of SBA County, southeastern SBA County, and the Santa Clarita Valley. This is already nicely accounted for in the current batch of wind advisories, with the only addition being the far western portion of the Antelope Vly. The low level flow should turn northeasterly late tonight and Wed morning. This should bring an end to advisory level winds in most area by late tonight. For late tonight and Wed morning, some gusty NE winds are possible in the mtns of L.A./eastern VTU County, and locally in the valleys, but expect the northeast winds to remain below advisory levels. The WRF shows some stratus moving into coastal areas of L.A. County and portions of the southern Central Coast and Santa Ynez Valley late tonight and Wed morning, but with weak offshore flow developing, any low clouds should be gone quickly Wed morning. Heights across the region will be lower on Wed, but 950 mb temps will actually rise west of the mountain due to the weak offshore flow. Therefore, expect a few degrees of warming in most areas on Wed, especially in the valleys and across interior sections of the coastal plain. A strong-"ish" vort will move south southwestward thru the Great Basin Wed night and Thu, causing a weak closed upper low to develop over southern Nevada and southwestern Utah, with a trough extending southwestward into the forecast area. There is still some uncertainty as to how much stratus will develop Wed night and Thu morning, but at this point, it does look as though there will be more extensive low cloud coverage, affecting coastal areas of L.A./VTU Counties, the Central Coast and Santa Ynez, and possibly the lower valleys of L.A./VTU Counties. With lowering heights, cooling at 850 and 950 mb, and increasing onshore flow, expect a few degrees of cooling in most areas Thu. .LONG TERM (FRI-MON)...07/506 AM. What happens with the upper low over Nevada will have implications on the resultant weather across the forecast area Fri thru Mon. The operational runs of the GFS and EC are in moderately good (but not great) agreement, showing the upper low drifting westward into southeastern CA Fri. The GFS shows the upper low farther south and west than does the EC, which would bring some cooling to most of the region Fri. The EC actually shows slight warming Fri, since it indicates low level flow turning weakly offshore. The upper low will move little Fri night, then should move to the east on Sat, with a weak ridge building into the region during the day. Expect mostly minor changes in max temps on Sat. The stratus pattern is very uncertain. With a broad trough extending into the region, would typically expect some night thru morning low clouds Thu night and Fri night, especially since we are heading into mid May, so areas of low clouds in coastal/lower valley areas looks reasonable. However confidence in the low cloud forecast is rather low. Overall, a generally benign pattern looks to be setting up for Sun and Mon. The weak ridge which will move into the area late Sat will flatten out. Heights will lower a bit and onshore flow will increase, so there should be some cooling in most area Sun and Mon. && .AVIATION...07/1118Z. At 1030Z, there was no marine layer or inversion at KLAX. Overall, moderate to high confidence in 12Z TAF package. Thru the period, high confidence in most sites being CAVU. The only exceptions will be KPRB (with a 40% chance of IFR conditions 12Z-16Z) and KLAX/KLGB/KSMO (with a 50% chance of CIG/VSBY restrictions after 09Z). With gusty winds this afternoon, there is a 50% chance of MVFR VSBYs in blowing dust for KPMD/KWJF 20Z-04Z. KLAX...Overall, moderate confidence in 12Z TAF. High confidence in CAVU conditions thru this evening. For tonight/Wednesday morning, there is a 50% chance that CIG/VSBY restrictions will not develop 10Z-17Z. No significant easterly wind component is expected. KBUR...High confidence in 12Z TAF. && .MARINE...07/837 AM. For the Outer Waters, high confidence in current forecast. Today through tonight, Gale force winds are expected and GALE WARNINGS are in effect. For Wednesday and Wednesday night, a combination of Small Craft Advisory (SCA) level winds and seas are expected. For Thursday through Saturday, winds and seas will remain below SCA levels. For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. SCA level winds are likely this afternoon and evening. For Wednesday, there is a 30% chance of SCA level winds in the afternoon/evening hours. For Thursday through Saturday, high confidence in winds and seas remaining below SCA levels. For the Inner Waters south of Point Conception, high confidence in current forecast. Across the western half of the Santa Barbara Channel, SCA level winds are expected this afternoon and tonight. Otherwise across the southern Inner Waters, winds and seas will remain below SCA levels through Saturday. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory remains in effect from 7 PM this evening to 3 AM PDT Wednesday for zones 88-350-352-353-376-377. (See LAXNPWLOX). Wind Advisory remains in effect from 4 PM this afternoon to 3 AM PDT Wednesday for zones 349-351-378-381. (See LAXNPWLOX). Wind Advisory in effect from 4 PM this afternoon to 3 AM PDT Wednesday for zone 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 from 3 PM this afternoon to 3 AM PDT Wednesday for zone 650. (See LAXMWWLOX). Gale Warning in effect until 3 AM PDT Wednesday for zones 670-673-676. (See LAXMWWLOX). && $$ PUBLIC...DB/Kittell AVIATION...RAT MARINE...RAT/Schoenfeld SYNOPSIS...DB weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox