Area Forecast Discussion
Issued by NWS Los Angeles, CA

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332 FXUS66 KLOX 191811 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 1111 AM PDT Sun May 19 2024 .SYNOPSIS...19/856 AM. Low clouds will continue to be a staple of the forecast for coast and valleys through Monday, and struggling to clear each afternoon. Breezy onshore winds will occur across the interior valleys and adjacent foothill areas each afternoon and evening. More sunshine with slight warming is expected Tuesday and Wednesday as onshore flow weakens. Then cooler with increasing marine layer clouds again the latter half of next week. && .SHORT TERM (TDY-TUE)...19/903 AM. ***UPDATE*** Our deep marine pattern continues as a long wave upper level trough remains in place along the West Coast of North America. Low clouds will again be slow to clear today and temperatures will be 4-8 degrees below normal. Strong onshore flow remains as well so it will be another breezy day in the Antelope Valley. ***From Previous Discussion*** Monday looks to be the coolest day of an already cool week. Look for a weak and dry upper low to pass over Srn CA. Look for an even deeper marine pushing well into the mtn passes (possible moving through the Soledad canyon and into Palmdale). Areas of morning drizzle are likely. While there is likely going to be another round of slow to no clearing, there is a chance the marine layer will deepen to the point of collapse and there will be decent clearing. While the csts/vlys will cool by 1 to 3 degrees the interior will drop 4 to 8 degrees. Max temps across the csts/vlys will only be in the 60s with just a couple 70 degree readings. Max temps will end up 6 to 12 locally 15 degrees blo normal. Short range deterministic and ensemble forecasts all area that there will be 3 to 4 mbs of offshore trends (weaker onshore flow) on Tuesday. Look for much quicker and better clearing across the board along with 4 to 8 degrees of warming due to weaker seabreezes and higher hgts. .LONG TERM (WED-SAT)...19/317 AM. Relentless long wave troffing will dominate the long term forecast. At the same time the east pac will reassert itself while thermal low will also be present in the afternoon. This will lead to a steady day by day increase in the onshore flow with a double digit push to the east next Friday and Saturday afternoons. Look for a steady increase in marine layer coverage with slow to no clearing rearing its head later in the week and heading into the weekend. The gusty afternoon winds will also return with low end advisory level gusts likely in the western Antelope Vly. Max temps will cool a little on Wednesday and then drop 3 to 6 degrees on Thursday with little change on tap for Friday and Saturday. Look for another round of max temps mostly in the 60s for the csts and vlys or 5 to 10 degrees blo normal. && .AVIATION...
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19/1810Z. At 17Z at KLAX, the marine layer was 2700 ft deep. The top of the inversion was at 4200 feet with a temperature of 16 C. Good confidence in desert TAFs. Moderate confidence in the remainder of TAFs. There is a 20 percent chc that sites with afternoon clearing will remain cloudy. Flight Cat transitions may be off by 2 hours and cig hgts off by 300 ft. There is a 40 percent chance KPRB remains VFR after clearing early this afternoon. KLAX...Moderate confidence in TAF. There is a 30 percent chc of BKN035 conds through the afternoon. No significant E wind component expected. KBUR...Moderate confidence in TAF. There is a 10 percent chc of BKN025 conds through the afternoon.
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&& .MARINE...
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19/924 AM. High confidence in Small Craft Advisory (SCA) seas and/or northwest winds forming tonight over the offshore waters from the Central Coast to San Nicolas Island. There is a 30 percent chance of SCA for the western Santa Barbara Channel each evening. These conditions will continue through Monday and likely beyond. Seas will be building everywhere as a result, with short period dominant seas over most nearshore waters by Sunday Night or Monday. SCA conditions are unlikely elsewhere. Southeast winds will form each morning over the nearshore waters from Santa Barbara to Orange County starting Monday or Tuesday. These winds can enhance to near 15 knots through passages and channels. A long period south to southwest swell will peak Sunday and Monday with heights of 2 to 4 feet. This will create larger than usual breaking waves nearshore as well as some stronger currents near most harbor entrances.
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&& .LOX WATCHES/WARNINGS/ADVISORIES...
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CA...Beach Hazards Statement in effect through Monday evening for zones 87-362-366. (See LAXCFWLOX). PZ...Small Craft Advisory in effect until 3 AM PDT Tuesday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect from 9 PM this evening to 3 AM PDT Tuesday for zones 673-676. (See LAXMWWLOX).
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&& $$ PUBLIC...MW/Rorke AVIATION...Munroe MARINE...Kittell/RM SYNOPSIS...MW weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox