048 FXUS66 KLOX 290037 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 537 PM PDT Sun Oct 28 2018 .SYNOPSIS...28/152 PM. Patchy overnight and morning low clouds and fog through Tuesday morning. Winds will be gusty across portions of the region tonight through Monday night with slightly cooler temperatures. The winds will then strengthen and turn offshore Tuesday through Thursday and temperatures will warm again. && .SHORT TERM (TDY-WED)...28/152 PM. Latest visible satellite imagery indicated most all of the stratus has scoured out to just off the coast. There were plenty of high clouds streaming across the southern half of the forecast area with just variable high clouds to the north. The upper ridge across the region will begin to weaken and shift southeast of the area. A broad upper trough will move in over the region, and become more amplified as a strong area of high pressure sets across the Eastern Pac through at least Wed. The combination of lower H5 heights and boundary layer temps indicate some cooling, as well as the onshore flow will allow for widespread cooling today except a few degrees of warming across the Antelope Valley. Expect 2 to 5 degrees of cooling today. For this evening, a N to S gradient will increase over the area. This will cause sub-advisory level Sundowner winds to develop tonight around 25 to 30 mph then strengthen Monday night into Tuesday evening. The strongest gusts are expected to occur through the passes and canyons of the Santa Ynez Mountain Range and below passes and canyons west of Refugio ranging between 35 and 45 mph, except local gusts up to 50 mph near Montecito Hills late evening through the overnight hours. A wind advisory will likely be needed for this area tomorrow night and possibly Tuesday night. Expect gusty NW winds to affect the Central Coast Monday afternoon and evening, possibly needing a wind advisory at that time. The northerly winds will also affect the I-5 Corridor as well this evening and again tomorrow evening. Some winds are expected to spread south into the Santa Clarita Valley and could reach the San Fernando Valley. Once again, only expecting sub- advisory winds for these areas. Due to the increased N-S gradients, expect low clouds tonight to be confined to coastal sections and could sneak into the San Gabriel Valley as models are hinting at an eddy developing due to the strong NW Gale winds off the Central Coast. With less confidence, some low clouds could develop across portions of the Central Coast, but NE flow could abate that from occurring, or could scour out before Monday's sunrise. Some low clouds may also affect interior sections of SLO county thru the interior and northern slopes of the mtns of SBA and VTU Counties. As far as high temps, there is some cooler air advection moving in across the SLO/SBA interior areas tonight, but especially for Monday night into Tue. Normally, with just the offshore flow expected, would expect high temps to soar across the Central Coast Mon and Tue, but the cool air advection will moderate the air only slightly warmer across the Central Coast. but not expecting to reach into the 80s Monday, but a slightly better chance on Tue. Overall, the coolest day looks to be Monday with only a slight increase trend on Tuesday except for some modest cooling across the interior areas of L.A. and Ventura Counties due to northerly gradients. By Tuesday evening into Wednesday, the northerly surface gradient turns northeasterly and sets up a moderate Santa Ana wind event. The upper ridge over the Eastern Pac will begin to nudge eastward into California allowing for additional warming aloft. Low clouds will not be in the picture and high temps will rise significantly across coast and coastal valley locations due to the building ridge aloft and offshore flow. Highs will reach the lower to mid 80s for these areas and will be cooler for interior areas. .LONG TERM (THU-SUN)...28/205 PM. An upper ridge will continue to amplify from just off the West Coast Thursday then shift slowly eastward thru Fri. Offshore flow will weaken gradually Thu and Fri. Still expect some locally gusty NE winds both days, but probably below advisory levels. Although the offshore winds will weaken, the upper ridge will continue to hang around the area, and continue to bring very warm temperatures to the area. Better warming across the valleys an inland areas Thu/Fri while models continue to show weak offshore flow across the Central Coast as well. Highs for the Central Coast might be a tad overdone along the immediate coast, especially of the seabreeze picks up earlier than models suggest. The upper ridge will begin to break down Sat, but H5 heights and thickness lvls only lower slightly. However onshore gradients finally turn onshore weakly for the weekend and should allow a modest cooling trend for inland areas with better cooling along the coast, especially the Central Coast. Night thru morning low clouds are not expected to be much of an issue, until possibly the weekend with potential dense fog along coastal areas. Not expecting low clouds to reach the valleys. && .AVIATION...29/0036Z. At 0035Z, the marine layer depth was 500 feet or less. The top of the inversion was 2300 feet with a temperature of 26 degrees Celsius. Overall, low to moderate confidence with 00Z coastal TAFs and high confidence in valley/desert TAFs. Shallow inversion may produce patchy LIFR/VLIFR conditions at LA coastal sites and KSMX. KLAX...low confidence in 00Z TAF. There is a 30 percent chance IFR/LIFR conditions don't develop as there are considerable high clouds overhead and weak offshore flow. KBUR...high confidence in 00Z TAF. VFR conditions will prevail through the TAF period. && .MARINE...28/131 PM. For the Outer Waters, very low confidence in current forecast. The latest model run shows stronger winds for the outer waters with winds in the western portions much stronger than near the coast. It is a very tough call, but for purposes of erring on the side of caution, a Gale warning has been posted for late this afternoon through Tue night for the outer waters. It may be true that most Gale force gusts will be confined to extreme western portions and the late afternoon through evening time periods, but the models have been a little inconsistent lately, and caution is needed at this time. For the Inner Waters north of Point Sal, high confidence in current forecast. SCA level winds will develop this afternoon and evening with a 70% chance of SCA level winds Monday afternoon and evening. For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. For the western half of the Santa Barbara Channel, there is a 60% chance of SCA level winds late this afternoon and tonight as well as late Monday afternoon and night. Otherwise, winds and seas are anticipated to remain below SCA levels through Thursday. && .FIRE WEATHER...28/1244 PM. Sundowner winds are expected to develop tonight then strengthen Monday night into Tuesday evening, when gusts are generally expected to range between 35 and 45 mph across the passes and canyons of southern Santa Barbara county, except local gusts up to 50 mph near Montecito Hills. Initially humidities will be elevated tonight, but are expected to lower late Monday into Tuesday evening across southern Santa Barbara county when there will be elevated to brief critical fire weather conditions. From Tuesday night through Friday, periods of gusty offshore winds are expected to bring warm and dry conditions to the region, resulting in elevated to brief critical fire weather conditions, especially in Los Angeles and Ventura counties Tuesday night into Wednesday morning. The strongest offshore winds this week are expected to occur Tuesday night into Wednesday morning, when gusts up to 45 mph will be possible across the mountains of Los Angeles and Ventura counties, with gusts up to 35 mph across coastal and valley areas. Minimum humidities are generally expected to lower to between 8 and 15 percent on Wednesday. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...Small Craft Advisory in effect until 9 PM PDT this evening for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect from 9 PM this evening to 3 AM PDT Monday for zone 650. (See LAXMWWLOX). Gale Warning in effect until 3 AM PDT Tuesday for zones 670-673-676. (See LAXMWWLOX). && .HAZARD POTENTIAL OUTLOOK (WED-SUN). Gusty offshore winds will increase fire risk Wednesday. && $$ PUBLIC...Kaplan AVIATION...MW MARINE...Sweet FIRE...Gomberg SYNOPSIS...Kj weather.gov/losangeles