Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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857 FXUS66 KLOX 221043 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 343 AM PDT Sun Sep 22 2024 Updated aviation section and synopsis .SYNOPSIS...22/342 AM. A warmer and drier pattern will establish through Monday as high pressure aloft builds over the region. A warmer air mass will likely remain in place through much of the week away from the coast, with the hottest daytime temperatures forecast for Monday. Onshore flow will persist through the period, maintaining night through morning low clouds and fog for coastal areas and some of the valleys. && .SHORT TERM (TDY-TUE)...22/313 AM. 584 dam hgts will persist through Tuesday as a weak high hgt upper pinches off and retrogrades a 100 miles west of Pt Conception. The weak sfc reflection of the low will help bring offshore trends and even weak offshore flow in the morning hours to the area esp Monday. Currently the marine layer has been smooshed down to 1200 ft which is still deep enough to bring low clouds to the lower vlys (a stratus surge down the Salinas River Vly has also brought low clouds to the Paso Robles area). Low clouds also cover all of the coasts. Clearing should be quicker and more complete today due to the offshore trends. The beaches will warm a few degrees today. Away from the beaches, however, there will be about 6 degrees of warming further inland and 8 to 12 degrees in the vlys. Offshore trends will continue on Monday and there will be less marine layer clouds and an even quicker burn off. This will allow for another 3 to 6 degrees of warming. Monday will be the warmest day of the next 7 with max temps 3 to 6 degrees above normal. A slight increase in onshore flow and a slight decrease in hgts is expected Tuesday. This will cool temperatures a couple degrees across coast and valleys but either little change or slight warming across the interior. .LONG TERM (WED-SAT)...22/330 AM. Not much excitement on tap in the extended period. The faster more dynamic flow will be well to north and there will be weak flow over Srn CA. Gradients Wed to Fri to the east will increase to moderate but the N/S grads will remain weak and may even be slightly offshore in the morning hours. There will be better onshore trends on Saturday. The night through morning low clouds pattern will continue over the coasts will local penetration into the lower vlys (esp the Santa Ynez Vly). Look for 3 to 5 degrees of cooling Wednesday with the increase in onshore flow. Thursday`s temps will be very similar to Wed`s. Perhaps some barely noticeable warming Friday and then 2 to 3 degrees of cooling on Saturday as there is another noticeable increase in the onshore flow both to the north and east. In general max temps will be above normal across the interior but a few degrees blo normal across the coasts and vlys. && .AVIATION...22/1040Z. Around 0715Z, the marine layer depth was around 1200 feet deep at KLAX. The top of the marine inversion was around 2100 feet with a temperature near 18 degrees Celsius. There was another inversion above up to around 4100 feet. High confidence in the current forecast for desert terminals, otherwise moderate confidence in all other terminals. Higher confidence in flight categories. Less confidence in timing. LIFR to IFR conditions at terminals north of Point Conception and IFR to MVFR conditions will continue at terminals south of Point Conception through at least 16Z. Timing of clearing could off by up to four hours. There is a moderate chance of LIFR conditions at terminals north of Point Conception through 14Z. Farther to the south, there is a low-to-moderate chance of VFR conditions continuing at Los Angeles County valley terminals. There is a high-to-likely chance of LIFR to IFR conditions returning tonight and into Monday morning. KLAX...IFR to MVFR conditions will continue through at least 20Z, and possibly as late as 23Z. There is a 20 percent chance that KLAX may not clear at all. A return of IFR to MVFR conditions could occur as soon as 01Z or as late as 03Z. Higher confidence exists in IFR conditions after 03Z. KBUR...There is a 20 percent of VFR conditions continuing through the period, otherwise IFR to MVFR conditions will spread into KBUR as soon as 1130Z, or as late as 13Z. VFR conditions will develop between 16Z and 17Z. && .MARINE...22/259 AM. High confidence in the current forecast through Thursday, then moderate confidence thereafter. Winds and seas will remain below Small Craft Advisory (SCA) levels through at least Thursday, except for a moderate-to-high (30-50 percent) chance of SCA level winds this afternoon and evening. The highest chances of SCA levels this afternoon and evening will be for an area in the vicinity of Point Conception. On Thursday afternoon, there is a high (40-50 percent) chance of SCA levels winds for the waters beyond 10 NM offshore along the Central Coast southeast to San Nicolas Island. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...Rorke AVIATION...Hall MARINE...Hall SYNOPSIS...Smith/Hall weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox