Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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902 FXUS66 KLOX 252048 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 148 PM PDT Wed Sep 25 2024 .SYNOPSIS...25/112 PM. Low clouds and fog will continue across coastal and valley areas through the weekend with clearing to the beaches and below normal temperatures. Far interior areas will remain above normal. Otherwise, the quiet weather pattern will continue. && .SHORT TERM (TDY-SAT)...25/129 PM. Cooler than normal temperatures are expected to continue through the weekend for coast and valleys as a trough lingers along the West Coast. Latest ensemble based guidance indicates an 80-90% probability of valley temperatures under 95 through Sunday and lower than 85 for Downtown LA. Deterministic models do indicate some weakening of the onshore flow the next couple days which may lead to slightly earlier clearing of low clouds in the valleys but overall the cooler pattern will continue. Farther inland from the mountains to the Kern County line temperatures will remain above normal by 4 to 8 degrees. Winds will be generally on the lighter side with those weakening gradients. Otherwise, the very quiet and June-like conditions will continue. .LONG TERM (SUN-WED)...25/141 PM. Looks like a return to above normal temperatures is likely starting Monday as the weak upper low shifts west in response to building high pressure from the east. Although there are still some cooler ensemble solutions, the vast majority are showing the warmer pattern and weakening onshore flow. In fact, roughly 10% of the solutions show a low grade Santa Ana event with some northeast winds across the interior. The deterministic GFS shows significant warming at lower levels starting Monday with 950mb temps jumping above 30c both Monday and Tuesday and 500mb heights close to 595dam. 90th percentile temperatures, considered a reasonable worst case scenario, get close to 110 in the warmer valleys Tuesday and mid to high 90s for Downtown LA and other inland coastal areas, including the Central Coast. Some cooling is expected Wednesday but above normal temperatures will likely last through next Thursday. && .AVIATION...25/1818Z. At 17Z over KLAX, the marine layer was 2000 ft deep. The top of the inversion was 2800 ft with a temperature of 23 Celsius. Moderate confidence in similar to slightly low ceilings and visibility for the next 24 hours as the previous. Slow or no clearing likely again for KSBA KOXR KSMO KLAX, with a 60-80% percent chance of 2 hours or less of VFR conditions. Lower chances of ceilings at KVNY KBUR KPRB tonight compared to last night, but still a 60% chance of forming. High confidence in VFR at KWJF KPMD through at least Thursday. Otherwise, high confidence in ceilings at all other sites, likely dropping to LIFR for at least a few hours. KLAX...70% chance of 2 hours or less of VFR conditions today (best chance for VFR in 20-24Z window), and a 50% chance of no clear at all. Moderate confidence in similar ceilings and vis tonight as last night, with IFR most common and a few hours of LIFR 06-14Z. High confidence in no significant east wind component. KBUR...60% chance of IFR/LIFR ceilings returning tonight in the 05-09Z window. There is a 30% chance of VLIFR fog 11-15Z. && .MARINE...25/1256 PM. Moderate confidence in low-end Small Craft Advisory (SCA) conditions forming over the waters south of Point Sal this afternoon and evening, including the nearshore waters from Ventura to Orange County. High confidence that these SCA winds will return to their traditional areas (offshore waters from the Central Coast to San Nicolas Island) for Thursday afternoon and Night. High confidence in fairly light winds staying below SCA levels Friday morning through Saturday morning. Moderate confidence in SCA winds returning Saturday or Sunday and persisting through Monday before another weakening period returns Tuesday and Wednesday. Dense fog with visibilities under 1 mile will continue to be a concern through at least Friday, with the highest chances each night and morning and along the Central Coast. Please refer to the marine weather statement for more information. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...Small Craft Advisory in effect until midnight PDT tonight for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 9 PM PDT this evening for zone 655. (See LAXMWWLOX). Small Craft Advisory in effect from 5 PM this afternoon to 3 AM PDT Thursday for zones 673-676. (See LAXMWWLOX). && $$ PUBLIC...MW AVIATION...RK MARINE...RK SYNOPSIS...MW weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox