897 FXUS66 KLOX 160424 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 824 PM PST Fri Feb 15 2019 .SYNOPSIS...15/703 PM. Scattered rain and mountain snow showers are expected to continue tonight through Saturday as a cold storm system moves through. An even colder system will move through Sunday, bringing additional mountain snow. Conditions will dry out early next week but temperatures will remain below normal. && .SHORT TERM (FRI-MON)...15/823 PM. A cold storm system has brought rain and mountain snow showers to the region today. As of 8 pm, radar showing the first rain band has shifted into eastern LA county and points south and east while the next organized band of showers is pushing through SLO and SBA counties, with the leading edge moving into western Ventura county. Rainfall amounts so far today have generally ranged between 0.10 and 0.50 inches, with some foothill/coastal slopes locations ranging between 0.50 and 0.75 inches. Rainfall intensities have generally been light, but brief and localized heavy downpours have occurred, with a few automated stations reporting rates of 0.20 inches in a 30 minute time period. As the flow turns more northwesterly later tonight into Saturday, most of the shower activity is expected to be confined to the north facing mountain slopes and areas north of Point Conception. Snow levels are ranging between 3500 and 4500 feet this evening, and is expected to lower to between 3000 and 3500 feet by Saturday morning. Some light snow accumulations with icy road conditions and gusty winds are likely across Interstate 5 near the Grapevine overnight into Saturday, likely creating significant travel delays. With the lowering snow levels, will also likely see light snow accumulations in the foothills of the Antelope Valley and Cuyama Valley. Gusty west winds of 40 to 50 mph will continue across the Antelope Valley, prompting the extension of the wind advisory through Saturday. A second and colder system will move through Southwest California on Sunday. While this system will likely have a mostly over-land trajectory and limited moisture, it has the potential for significant low snow level impacts. With plenty of cold air aloft, strong jet dynamics, and a low level southwest onshore flow, most areas should see some precipitation during the day Sunday. Precipitation amounts will generally be less than 0.25 inches with this storm system, but with the previously mentioned cold air aloft and jet dynamics, cannot rule some brief and localized heavier downpours which could locally enhance precipitation totals. By Sunday night, most of the shower threat will be confined to the north facing mountain slopes, including Interstate 5 near the Grapevine. Snow levels with this second storm on Sunday are expected to range between 2000 and 3000 feet. Snow accumulations of 2 to 5 inches are likely across the mountains, with 1 to 2 inch accumulations possible in the foothills of the Antelope Valley and Cuyama Valley. NAM-12 model sounding also showing the potential for light snow accumulations down to the valley floor in both the Antelope Valley and Cuyama Valley on Sunday into Sunday evening. The low snow levels could pose significant travel impacts on Sunday into Sunday night. A larger portion of Interstate 5 from the Grapevine to Castaic could be impacted by snow showers and icy roads, as well as portions of Highways 14 and 138 through the Antelope Valley and Soledad Canyon. Winter weather advisories are in effect for the mountains of Los Angeles, Ventura, and Santa Barbara counties through Sunday night, and will potentially be extended to the Antelope Valley and Cuyama Valley for the Sunday system. *** From previous discussion *** Monday we transition to a drier, northerly flow pattern. Could still be some lingering low elevation snow showers over the Grapevine but otherwise just a cool and breezy day, continuing our long stretch of below normal temps. Morning lows could require some frost/freeze headlines in some areas. And northerly flow could generate some low end advisory level winds across srn SB County and possibly other areas as well. .LONG TERM (TUE-FRI)...15/142 PM. Another dry but cool day Tuesday and the first part of Wednesday. At that point another cold system will drop south along the West Coast. Models have trended a little wetter with this, especially by Thursday. Thicknesses drop to 527dm so this has the potential for being another very low snow level event. Precip amounts likely will be fairly light again but impacts to mountain roads due to the lower snow levels will probably be the main issue. Then dry and cool Friday. && .AVIATION...15/2356Z. At 2345Z at KLAX...there was no marine inversion present. Generally moderate confidence in the 00Z TAFs, however there is hi confidence in low clouds and lowered vsbys to MVFR with scattered showers at times through tonight for KPRB, KSBP and KSMX, and through later tonight for KSBA, KCMA, KOXR, KSMO, KLAX, KLGB, KBUR and KVNY. The timing of lowering cigs/vsby and changes between flight cats may be off +/- 1 to 3 hours. There is also a small chance (20%) that conditions could briefly deteriorate to IFR at times with any heavier showers. Otherwise, VFR conditions can be expected through Sat morning. For KWJF and KPMD, there is moderate to hi confidence in the TAFs. VFR conditions should generally prevail thru Sat except for brief MVFR conditions with scattered showers through this evening. Gusty SW-W winds will prevail thru Sat. LAX...Generally moderate confidence in the 00Z TAF, however there is hi confidence in low clouds and lowered vsbys to MVFR with scattered showers at times through this evening. The timing of lowering cigs/vsby and changes between flight cats may be off +/- 1 to 3 hours. There is also a small chance (20%) that conditions could briefly deteriorate to IFR at times with any heavier showers. Otherwise, VFR conditions can be expected through Sat evening. KBUR...Generally moderate confidence in the 00Z TAF, however there is hi confidence in low clouds and lowered vsbys to MVFR with scattered showers at times through this evening. The timing of lowering cigs/vsby and changes between flight cats may be off +/- 1 to 3 hours. There is also a small chance (20%) that conditions could briefly deteriorate to IFR at times with any heavier showers. Otherwise, VFR conditions can be expected through Sat morning. && .MARINE...15/754 PM. Moderate to high confidence in predominantly SCA level conds across the outer waters and northern inner waters through the weekend, except for a 40% chance of Gale Force wind gusts for the outer waters Saturday night through Sunday night, where a Gale Watch was issued. SCA conds are expected to continue either due to winds or seas through at least Mon night across the outer waters, and possibly through Tue. Across the northern inner waters, winds and seas should drop below SCA levels Sun night. Across the southern inner waters and the SBA Channel, winds are increasing to SCA levels, and the gusty winds will continue through late Sunday night, especially across western portions. Seas should rise to above SCA levels Sat and persist thru Sun night as well. A large long period NW swell is moving into the waters tonight, and will continue to affect the coastal waters through the weekend. The combination of large swell and large steep wind waves will create dangerous seas across much of the coastal waters over the holiday weekend. && .BEACHES...15/155 PM. An increasing northwest swell in the coastal waters will bring high surf to the Central Coast beaches by early this evening and to the west-facing beaches of Ventura and Los Angeles Counties tonight. Surf will peak later tonight and Saturday then slowly subside Saturday night into Sunday evening. Surf up to 17 feet can be expected on the Central Coast, up to 9 feet for Ventura County, and 8 feet for Los Angeles County. With increasingly high astronomical tides, there is the potential for minor coastal flooding for low-lying coastal areas in the Advisory area around the early morning high tides both Saturday and Sunday. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...High Surf Advisory in effect until 4 PM PST Sunday for zones 34-35. (See LAXCFWLOX). High Surf Advisory in effect until 9 PM PST Sunday for zones 40-41. (See LAXCFWLOX). Winter Weather Advisory in effect until 3 AM PST Monday for zones 52>54. (See LAXWSWLOX). Wind Advisory in effect until 6 PM PST Saturday for zone 59. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 3 AM PST Monday for zones 645-650-655. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PST Sunday for zone 670. (See LAXMWWLOX). Gale Watch in effect from late Saturday night through late Sunday night for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until noon PST Sunday for zones 673-676. (See LAXMWWLOX). Gale Watch in effect from Sunday afternoon through late Sunday night for zones 673-676. (See LAXMWWLOX). && .HAZARD POTENTIAL OUTLOOK (MON-FRI). Low elevation snow is possible late Wednesday and Thursday potentially creating impacts on Interstate 5 and other roads through the mountains. Near or sub-freezing overnight temperatures are possible in many areas. && $$ PUBLIC...Gomberg/MW AVIATION...Gomberg/Sirard MARINE...Sirard/Smith BEACHES...Sirard SYNOPSIS...Stewart weather.gov/losangeles