751 FXUS66 KLOX 132221 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 221 PM PST Fri Jan 13 2023 .SYNOPSIS...13/208 PM. A series of storms will bring periods of rain and mountain snow to the area through Monday. High surf will continue across the beaches through at least Saturday evening and again next week. && .SHORT TERM (TDY-MON)...13/206 PM. A somewhat complicated pattern over the next 3-4 days as a series of storms move through the area. A weak system moved through earlier today and brought light rain to western SLO and Santa Barbara Counties. Models at one time indicated that this area of showers would progress through the remainder of the area overnight tonight but more recent HRRR runs have scaled back on this. Radars do show some light showers moving into Central Santa Barbara County this afternoon but it's looking less likely that it will survive much farther east as the core of the storm lifts northeast. At best probably just some sprinkles or very light showers tonight. The next system still on tap for Saturday and Saturday night and looks more or less on track in terms of timing and amounts. Lighter warm-frontal showers expected to develop at some point in the morning or early afternoon as south to southwest flow increases. In these cases showers often develop sooner than models expect, but in any case the primary focus will be on the main frontal band which is expected to come through between late afternoon for SLO and Santa Barbara Counties and evening for LA/Ventura Counties. It's during this period when rain rates will be at their highest. There have been a few hi res models today that have shown one hour rates as high as 0.80"/hr, though most of them have been closer to a half inch and that seems to be the most likely scenario. With these rates impacts will be slightly greater than what would normally occur with a storm of this magnitude since the ground is still fairly saturated from previous rain, but still just on the minor side, including small mud slides in the foothills and mountains, and typical minor road flooding. Amounts still projected to be around an inch for coast/valleys and 1.5-3 in the mountains. Snow levels will be at or above 7000' for most of this event so accumulations will be confined to higher elevations. For this reason have opted to go with a winter weather advisory rather than a winter storm warning as impacts for most of the mountain areas will be at elevations with very few people. The mountain resorts on the LA/San Bernardino County should do well with accumulations, especially at 8000' and above where a foot or more could fall. Rain and snow expected to taper off Saturday night as the flow quickly shifts to northwest. During this short period into Sunday morning snow levels will fall to around 5000' as the colder air moves in, however accumulations down to that level are expected to be minimal at best. There will be typical gusty southerly winds ahead of the front through Saturday night. The winter weather advisory will cover the winds in the LA/Ventura mountains. The Antelope Valley and interior SLO County will also see advisory level winds at times. A break in the weather most of Sunday until later in the afternoon and evening when the next storm arrives. This one has less moisture to work with but is a little colder and has the potential for convection at the end of it. Ensembles have been consistently producing about half the amount of rainfall, though if thunderstorms do develop (best chances later Monday into Monday night) rainfall totals could end being similar in those locations. The colder storm will bring accumulating snow to lower elevations (mainly 5000' and higher), but overall snow amounts will be lower than the with the Saturday system. There's a 10-20% chance that lingering moisture and northwest flow following the system could cause some light snow accumulations down to around 4000' late Monday night into early Tuesday. .LONG TERM (TUE-FRI)...13/221 PM. Models now trending dryer for Tuesday as the Monday system exits to the east and northwest flow takes over. Most ensemble solutions show a dry pattern the rest of the week with periods of gusty north to northwest winds. Then shifting to Santa Ana's later in the week into next weekend. && .AVIATION...13/1755Z. At 17Z at KLAX, there was a weak inversion at 400 ft with the top at 700 ft and a temp of 16 deg C. Moderate confidence overall in the 18Z TAFs. A mix of MVFR and VFR cigs/vsbys will prevail at all the coast and vly airfields thru the period. Changes between flight cats will vary as well and any changes may be off +/- an hour or two. For KWJF and KPMD, there is generally hi confidence in VFR TAFs thru the fcst period. KLAX...Moderate confidence overall in the 18Z TAF. Conds will be VFR for most of the fcst pd then MVFR conds are expected aft about 17Z Sat. The change in flight cats may be off +/- an hour or two. KBUR...Moderate confidence overall in the 18Z TAF. Conds will be VFR for most of the fcst pd then MVFR vsbys are expected aft about 17Z Sat, with a 30%-40% chance of MVFR cigs as well. The change in flight cats may be off +/- an hour or two. && .MARINE...13/116 PM. For the Outer Waters, moderate to high confidence in the current forecast. Small Craft Advisory (SCA) conds are expected at least through late Sunday night due to SCA level seas and/or winds as more Pacific storms move into the area. There will then be a 40%-50% chance of SCA levels winds and seas Monday through Wednesday. There is also a 40%-50% chance of gale force gusts for the northern zone (PZZ670) Sunday night and Monday. Peak seas during the forecast period are expected Monday night with seas up to 15-20 feet. For the Inner Waters north of Point Sal, moderate to high confidence in the current forecast. SCA conds are expected at least through late Sunday night due to SCA level seas and/or winds. There will then be a 40%-50% chance of SCA levels winds and/or seas Monday through Wednesday. Peak seas during the forecast period are expected Monday night with seas up to 16 to 19 feet possible. Large, breaking waves will be possible at harbor entrances through Saturday, and again Monday afternoon through Tuesday. For the Inner Waters south of Point Conception, moderate to high confidence in the current forecast. SCA conds are expected at least through late Sunday night due to SCA level seas and/or winds. There will then be a 40%-50% chance of SCA levels winds and/or seas Monday through Wednesday. Peak seas during the forecast period are expected Monday night with seas up to 9 to 12 feet possible. && .BEACHES...13/128 PM. A couple of storm system moving into the area will bring a 15-18 foot west swell with a 17-19 second period into the coastal waters through this evening then slowly subside through Saturday night. Therefore, a HIGH SURF ADVISORY is in effect for San Luis Obispo, Santa Barbara, and LA County Beaches through Saturday evening. A HIGH SURF WARNING is in effect for Ventura County Beaches due to the westerly component of this long period, large swell. There is less confidence in the LA County beaches reaching 15 feet and Central Coast beaches reaching 20 feet, so Advisories will continue. With another storm system coming in Monday into Tuesday, there is a likelihood that the advisories/warnings will be needed again by early next week. Warning level surf can cause beach erosion along with a threat of minor coastal flooding at the time of high tides, and damage to coastal structures and piers. For more details about the High Surf Advisories and Warnings, please refer to the Coastal Flood Advisory product (LAXCFWLOX). && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Winter Weather Advisory in effect from noon Saturday to 3 AM PST Tuesday for zones 53-54. (See LAXWSWLOX). Wind Advisory in effect from noon Saturday to midnight PST Saturday night for zone 59. (See LAXNPWLOX). High Surf Advisory in effect until 10 PM PST Sunday for zones 87-340-346-362-364. (See LAXCFWLOX). Wind Advisory in effect from noon to 9 PM PST Saturday for zones 345-353. (See LAXNPWLOX). High Wind Watch in effect from Saturday afternoon through Saturday evening for zones 345-353. (See LAXNPWLOX). High Surf Advisory in effect until 10 PM PST Saturday for zones 349-350. (See LAXCFWLOX). High Surf Warning in effect until 3 PM PST Saturday for zone 354. (See LAXCFWLOX). PZ...Small Craft Advisory in effect until 3 AM PST Monday for zones 645-650-655-673-676. (See LAXMWWLOX). Small Craft Advisory in effect until 3 PM PST Sunday for zone 670. (See LAXMWWLOX). && $$ PUBLIC...MW AVIATION...Sirard MARINE...Sirard BEACHES...Sirard SYNOPSIS...MW weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox