Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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879 FXUS66 KLOX 141610 AFDLOX Area Forecast Discussion...UPDATED National Weather Service Los Angeles/Oxnard CA 910 AM PDT Wed Aug 14 2024 .SYNOPSIS...14/907 AM. Daytime highs will be near normal for most areas through the weekend, followed by a warm up early next week. Patchy overnight to morning low clouds and fog will impact coastal areas at times. Tonight and tomorrow night gusty winds are likely across the Santa Barbara southwestern coast and the Antelope Valley during the evenings. && .SHORT TERM (TDY-FRI)...14/903 AM. ***UPDATE*** Marine layer stratus this morning was limited to the beaches along the Central Coast, and will likely clear completely by late morning. Today temperatures are generally expected to trend upwards by a couple degrees across the region, as a result of both an increase in 500 mb heights and weaker onshore pressure gradients. A Wind Advisory has been issued for this evening through tonight for the Santa Barbara Southwestern Coast including the western Santa Ynez Mountains, where gusts of 35 to 50 mph are expected to be fairly widespread. Even the eastern portion of the Santa Ynez range is likely to see gusts of 20 to 40 mph this evening. ***From Previous Discussion*** A 593 dam upper high currently to the SW of LA will slowly slide to the east over the next three days eventually ending up in NM. Hgts will oscillate between 592 and 594 dam. There will be weak onshore flow to the east each morning turning moderate in the afternoon. There will be weak offshore flow from the north in the morning, but weak onshore flow to the north in the afternoons. The marine layer will remain under 1000 ft due to the high hgts overhead. Due to the lack of an eddy, the offshore push from the north and only weak early morning onshore flow to the east the marine layer stratus will have a difficult time forming. Aside from the west coast of SBA county most coastal areas will be stratus free. Most areas will see slight warming each day as hgts rise slightly as the high passes to the south. The only notable exception will occur Friday along the SBA south coast and the VTA csts/vlys due to a stronger onshore push to the east in the afternoon. By Friday max temps will be a few degrees either side of normal with 70s at the beaches, 80 across the inland coastal area and 90s in the vlys. 3 to 4 mb N to S pressure gradients across SBA county tonight and Thursday night will produce Sundowner winds across the SBA South Coast. Wind advisories are likely across the western portion of the south coast with 35 to 50 mph gusts. The gusts will be weaker across the eastern portion where gusts will likely reach 25 to 35 mph. Downsloping compressional heating will keep elevated temperatures across the area through much of the evening. .LONG TERM (SAT-TUE)...14/324 AM. Good confidence in the weekend fcst. All deterministic and ensemble solutions show Srn CA stuck in between a large high pressure area centered over TX and a cool (for this time of year) upper low west of Portland OR. There will be dry SW flow over the area which will eliminate the threat of monsoon TSTMs. Hgts will lower a few dam to about 590 dam and onshore flow will increase. There may be an increase in the morning coastal stratus but this is not a for sure thing. Max temps will drop 2 to 4 degrees on Saturday and change little on Sunday. Not the best agreement in mdls for the Monday Tuesday forecast. The GFS continues the weekend pattern and indicates little day to day change. The EC on the other hand moves the upper high closer to the state kicking off a warming trend. The ensembles favor the warmer the EC solution and the forecast calls for 2 to 4 degrees of warming each day. The EC solution also opens the door for some monsoon moisture. Right now the TSTM threat is to the S and E of LA county but this could change as the forecast evolves. && .AVIATION...14/1125Z. At 10Z at KLAX, the marine layer was about 500 ft deep. The top of the inversion was at about 3100 ft with a temperature of 24 C. Very High confidence in CAVU TAFs for KPRB, KBUR, KVNY, KPMD, and KWJF. Moderate confidence in coastal TAFs. Low clouds were confined to southern portions of the Central Coast, with patchy low clouds in southern Ventura County. Most TAF sites will likely have VFR conds this morning, with the best chance of cigs with LIFR to VLIFR conds at KSMX and KOXR KLAX...Moderate confidence in TAF. There is a 25 percent chc of LIFR cigs between 13Z and 16Z this morning. There is a 25 percent chance of conds remaining clear tonight/Thu morning. No significant east wind component expected. KBUR...High confidence in CAVU TAF. && .MARINE...14/408 AM. For the outer waters, moderate confidence in current forecast. Small Craft Advisory (SCA) level winds are expected to increase to low end gale force this afternoon (60-70% chance), and continue at times through late Thu night. Winds will be strongest during the late afternoon through late evening hours. SCA level winds are expected (60% chance) from late Thu night thru late Sun night. For the inner waters N of Pt. Sal, moderate confidence in current forecast. SCA level winds and seas are likely (60% chance) much of the time this afternoon through Thursday night. When winds drop below SCA levels tonight/Thu morning, seas will likely remain at SCA levels. There is a 50-60% chance of SCA level winds and seas in the afternoon thru evening hours Fri thru Sun. For the inner waters south of Pt. Conception, moderate confidence in current forecast. SCA level winds are likely across the western Santa Barbara Channel during this afternoon thru late tonight, and again during the late afternoon thru late night hours Thu. There is a 20-30% chance of SCA level winds there during the afternoon/eve hours Fri thru Sun. Otherwise, conds will remain below SCA levels over the southern inner waters thru Sun night. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory in effect from 6 PM this evening to 6 AM PDT Thursday for zones 349-351. (See LAXNPWLOX). PZ...Small Craft Advisory in effect from 3 PM this afternoon to 5 AM PDT Friday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect from 3 PM this afternoon to 3 AM PDT Thursday for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 3 PM PDT this afternoon for zones 670-673-676. (See LAXMWWLOX). Gale Warning in effect from 3 PM this afternoon to 3 AM PDT Friday for zones 670-673-676. (See LAXMWWLOX). && $$ PUBLIC...Rorke AVIATION...DB MARINE...DB SYNOPSIS...RS weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox