FXUS66 KLOX 160344 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 844 PM PDT Sat Jun 15 2024 .SYNOPSIS...15/839 PM. Warm to hot conditions are expected again Sunday, although with slightly cooler highs, and continued gradual cooling each day through Monday or Tuesday. Temperatures will then trend upwards by the end of the upcoming week. Gusty north to northwest winds will affect portions of the region, including southern Santa Barbara County, the Interstate 5 cooridor, Antelope Valley, and the Central Coast, through Monday morning. && .SHORT TERM (SAT-TUE)...15/836 PM. Long duration strong northwest to north wind event impacting many parts of Southwest California through Monday. Areas experiencing these winds will continue to see elevated to brief critical fire weather conditions (please see fire discussion for more details). The strongest winds tonight are focused across southern Santa Barbara county, the Interstate 5 corridor, Ventura County mountains, and western Antelope Valley foothills. These areas are under a High Wind Warning where damaging wind gusts of 55 to 65 mph will be likely. Potential impacts include downed trees/powerlines as well as power outages. Areas under a wind advisory tonight include the Antelope Valley, Lake Casitas, and Santa Clarita Valley where gusts of 35 to 50 mph will be common. The Post Fire which originated near Gorman this afternoon has grown quickly to around 3600 acres as of 8 pm due to the strong northwest winds and low humidities. The Post Fire will continue to be under the influence of strong northwest to north winds through Monday morning, with the strongest winds expected tonight (after 10 pm) and again Sunday night. During these times, wind gusts of 50 to 65 mph can be expected (strongest across mountain ridgetops). As far as the sundowner wind event occurring this evening, we are seeing a very strong northwest pressure gradient between Santa Maria and Santa Barbara peaking at -6 mb as of 8 pm. This in combination with some upper level wind support and thermal advection is generating a strong and widespread sundowner wind event tonight. So far, the strongest winds have been focused between Gaviota and San Marcos Pass as well as the hills above Montecito where wind gusts of 40-58 mph have been observed. In addition, we saw a late afternoon temperature spike in areas that saw the downslope winds, with Santa Barbara Airport observing an impressive high temperature of 93 degrees. The sundowner winds have already impacted the Goleta area and adjacent foothills, with high resolution WRF model data showing the likelihood of the sundowner winds surfacing across other populated areas near Santa Barbara, Montecito, and Carpinteria (especially in the hills) within the next few hours. While the sundowner event looks to be fairly strong once again across western areas on Sunday afternoon/night, there does appear to be an eddy marine influence that will likely prevent the winds from surfacing across the lower elevations from Goleta to Montecito during Sunday's event. The widespread and long duration of the Sundowner winds in southern Santa Barbara county will make this a rather rare event for this time of year. Current satellite imagery showing clear skies with the exception of the smoke from the Post Fire impacting the Antelope Valley and portions of the LA/Ventura county mountains. Not much in the way of marine layer clouds expected tonight, with the exception of the LA county coast which could see some low clouds later tonight into Sunday morning. With heights lowering across the region on Sunday, looking for most areas to see at least a few degrees of cooling. However, interior areas and areas that continue to see downslope winds will likely experience temperatures above 90 degrees. Additional cooling is then expected on Monday. *** From previous discussion *** This pattern of winds, including warning level gusts, is expected to continue through Monday mornings. In fact, latest model runs show an upward trend in wind speeds for Sunday night through Monday morning, and this period may see the strongest wind of the event. This is due to the dropping of the upper level trough over the region, which allows for better upper level support as pressure contours become more alighted through the atmosphere. .LONG TERM (WED-SAT)...15/308 PM. There is good agreement among the GFS and ECMWF that the trough will persist over the region through Thursday, and that upper level heights will trend upwards through Friday. Late Friday into the weekend there is greater uncertainty in the upper level pattern, with the potential for a weak ridge to begin to build. Daytime highs are expected to slowly trend upwards Thurday through the weekend, crossing over to above normal for much of the region on Friday. The north-to-south gradient is expected to weaken Wednesday and even flip to onshore at times. Onshore flow (both from the west and south) is generally expected to be dominant through the period, and thus morning low clouds and fog are likely. However with rising upper level heights, the marine layer depth, and thus the inland extend of stratus will be limited to the coastal planes and will at times struggle to reach the coastal valleys. Clouds may cling to some beaches all day, especially in Los Angeles and Ventura Counties. Even with less dramatic pressure gradients than in the short term, gusty northerly-to-westerly winds will continue during the evenings for some wind- prone locations (e.g., the I-5 cooridor, the Antelope Valley and foothills, the Santa Barbara Southwestern coast). At this time, wind in the extended period are likely to be much lower impact than in the short term. && .AVIATION...15/2332Z. At 2000Z at KLAX, the marine layer was 1000 ft deep. The top of the inversion was at 3200 ft with a temperature of 28 C. Overall, moderate to high confidence in TAF package. CAVU conditions are anticipated at most locations through the period. However, CIG/VSBY restrictions in a returning marine layer will likely affect coastal LA County late tonight and Sun morning (60-80% chance), including KLAX, KLGB, and KSMO. Onset timing of CIG/VSBY restrictions may vary by +/- 2 hours from current forecasts. Gusty northerly winds will continue through the TAF period, and there could be some light turbulence/LLWS across the mountains and foothills. KLAX...Moderate to high confidence in TAF. There is a 40% chance that CIG/VSBY restrictions do not develop. No significant easterly wind component is expected. KBUR...High confidence in TAF as CAVU conditions are anticipated through the period. && .MARINE...15/843 PM. For the Outer Waters, high confidence in current forecast. Winds are expected to remain at Gale force levels through Monday. So, GALE WARNINGS will remain in place during this time (with a 20% chance of Storm force winds through Sunday night). Seas will peak in the 12 to 15 foot range through Monday. For Tuesday through Wednesday, winds will subside, but remain at Small Craft Advisory (SCA) levels while seas drop below 10 feet. For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. There is a 60-80% chance of Gale force winds through Sunday and a GALE WARNING remains in effect. Seas will peak between 10 to 13 foot through Sunday. For Monday through Tuesday, there is a 60-80% chance of SCA level winds. On Wednesday, winds and seas should remain below SCA levels. For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. For the western Santa Barbara Channel, high confidence in Gale Force Winds continuing through Sunday with a GALE WARNING remaining in effect. The winds will be strongest from mid channel and westward. For Monday through Wednesday, there will be a 60-80% chance of SCA level winds across the western half of the Santa Barbara Channel. Elsewhere across the southern Inner Waters, there is a 20-30% chance of SCA level winds through Sunday with high confidence in winds and seas below SCA levels Monday through Wednesday. Across all of the coastal waters, steep and dangerous seas can be expected this weekend into at least early this coming week. && .BEACHES...15/210 PM. Short-period wind waves, due to gale force winds over the nearby coastal waters, will generate significant surf conditions along the local beaches today through Monday. High surf, 4 to 7 feet, will impact the beaches of Ventura county. For the beaches along the Central Coast as well as Los Angeles county, elevated surf conditions will continue through Monday. Along with the surf conditions, dangerous rip currents can be expected through the weekend. && .FIRE WEATHER...15/843 PM. && Gusty northwest to north winds are expected to continue through Monday, peaking in intensity tonight with a secondary peak Sunday night into early Monday. Wind gusts of 30 to 50 mph will be common at times through the period for the Central Coast, mountains of Santa Barbara, Ventura and northwest Los Angeles County as well as Antelope Valley (strongest in the mountains and deserts). Isolated gusts to 65 mph will be likely in the strongest periods of wind across the Santa Ynez Range and I-5 corridor. Meanwhile, a warm and dry air mass will remain in place, with widespread 8 to 15 percent humidities across the interior on Sunday, and 12 to 20 percent on Monday. Poor overnight recoveries in the foothills are also expected. The warm and dry air will continue to descend into some coastal foothills on Sunday, including portions of southern Santa Barbara County. The combination of gusty winds, warm temperatures, and low humidities will continue to bring elevated to brief critical fire weather conditions across southern Santa Barbara county through Sunday night, and all interior areas through Monday. There is an increased risk for fast growing grass fires over much of the area, that could transition into wildfires where the fuel beds are most abundant and dry. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Beach Hazards Statement in effect through Monday evening for zones 87-340-346-362-366. (See LAXCFWLOX). Wind Advisory remains in effect until 11 AM PDT Sunday for zone 88. (See LAXNPWLOX). High Wind Warning now in effect until 11 AM PDT Monday for zones 349-351-353-376>378-381. (See LAXNPWLOX). Heat Advisory remains in effect until 8 PM PDT Sunday for zones 349>352. (See LAXNPWLOX). High Wind Warning remains in effect until 11 AM PDT Sunday for zones 350-352. (See LAXNPWLOX). High Surf Advisory in effect until 7 PM PDT Monday for zone 354. (See LAXCFWLOX). Wind Advisory in effect until 3 AM PDT Sunday for zones 356-383. (See LAXNPWLOX). PZ...Gale Warning in effect until 2 AM PDT Monday for zones 645-650. (See LAXMWWLOX). Gale Warning in effect until 7 PM PDT Monday for zones 670-673-676. (See LAXMWWLOX). && $$ PUBLIC...Gomberg/Schoenfeld AVIATION...Gomberg/Cohen MARINE...Smith BEACHES...RAT/Cohen FIRE...Gomberg/Munroe SYNOPSIS...DB/RS/CS weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox