FXUS66 KLOX 310419 AFDLOX Area Forecast Discussion...UPDATED National Weather Service Los Angeles/Oxnard CA 819 PM PST Mon Jan 30 2023 .SYNOPSIS...30/244 PM. Rain and mountain snow showers will taper off this evening. Gusty Santa Ana winds will affect wind prone areas tonight through Wednesday, strongest on Tuesday. Near to below freezing temperatures expected each morning through Thursday, coldest on Wednesday. Daytime temperatures will increase through Wednesday or Thursday, but remain below normal. Light rain possible north of Santa Barbara Friday, then again Saturday night into Sunday. Gusty north winds possible Monday and Tuesday next week. && .SHORT TERM (MON-THU)...30/751 PM. The upper low responsible for all of last nights and today's weather is now just to the WSW of San Diego. The rain assoc with the low is now to the south of LA county and only a slight chc of rain remains for the far SE portion of LA county and Catalina Island. Today was a cool and wet day south of Pt Conception and just a cool day north. The rainfall down south was very showery and non homogeneous. Downtown LA was on the high end of amounts with .75 inches and Camarillo Aiport was the big winner coming in .93 inches of rain. In general due to the more southerly track of the upper low the coasts received the most rainfall. 2 to 5 inches of snow fell and snow levels were down to 3000 ft which cover some of the lower coastal ranges. Max temps today were mostly in the mid 50s to near 60 or about 10 degrees blo normal. Attention now turns to winds. Gradients are trending strongly offshore and by morning there will be about 4 mb of offshore flow from both the north and east. More importantly the flow over Srn CA between a ridge to the NW and the upper low near San Diego is from the NE and this along with some cold air will produce a moderate offshore event with 30 to 50 mph (although the Magic Mtn Truck Trail sensor will likely far exceed those values). The Central Coast will also see some NE winds but these will be well under advisory levels. Will update forecast to touch up clouds and pops (reduce both) and kill the winter weather advisory. Rest of forecast looks good esp the freeze frost advisories which will affect the wind sheltered areas. From Previous Discussion... A cold air mass will linger behind our system, and with fast drying due to the offshore flow, night-time / early morning temperatures will be downright frigid. Wednesday looks to be the coldest, with the best combination of clear skies, dry air, and less wind. Interior valleys and mountains will be the coldest, with lows commonly in the 20 to 30 degree range. This includes the Antelope Valley, which could dip below 20 degrees for several hours Tuesday morning (20% chance) or Wednesday morning (50% chance). A Hard Freeze Watch will be issued for Wednesday morning. The other interior areas should stay above 20 and since they all have already had more than 2 freeze events, will not be considered for any frost freeze hazards. On the coastal side of the mountains, several areas will be flirting with freezing temperatures. The Central Coast and area around Ojai have the best chances, and a Frost Advisory and Freeze Watch will also be issued to cover that. More areas will likely need frost advisories for Wednesday morning. Early morning temperatures will remain cold but improved on Thursday as a narrow high pressure ridge forms aloft. This should bring temperatures up to almost normal away from the beaches. .LONG TERM (FRI-MON)...30/217 PM. The majority of projections are showing a trough of low pressure pushing into northern California early Friday, with a cold front pushing down the coast. By all indications, this front will dissipate somewhere over southwest California. As such, the potential for any rain decreases drastically further to the south. Taking the hint from the various ensemble models (EPS GEFS CCMC), those chances decrease quickly from San Luis Obispo County (50 percent) to Los Angeles County (10 percent). The most likely scenario keeps any rain north of Santa Barbara. If rain materializes, it will be light, with only a 10 percent chance of reaching 0.50 inches for San Luis Obispo. Another weak system looks to impact the area in a similar way Saturday night through Sunday, with any rain likely staying north of Santa Barbara. Between those two systems, weak offshore flow is possible on Saturday with a narrow ridge aloft. As a result, Friday through Sunday looks rather mild temperature-wise. Fairly high confidence of gusty north winds forming Sunday Night through Tuesday (70 percent chance of gusts over 35 mph in the mountains). Initially, lingering moisture may bring light showers to the north mountain slopes Sunday Night through Monday morning. Otherwise it should be clear and dry. Temperatures are very uncertainly however. The ECMWF ensemble 500 millibar heights give a great picture of that, with the range of possible outcomes between 550 decameters (cold) and 575 decameters (sort of warm). We will have to see what shakes out. && .AVIATION...31/0106Z. At 0005Z at KLAX, there was no marine layer nor a sfc based inversion. Good confidence in Cig/Vis fcst (LA county sites may hold on to the VFR cigs for a few hours longer than fcst). Moderate confidence in wind fcsts. NE winds may start 2 hours earlier than fcst. KLAX and KSMO may get 5 kt NE wind 11Z-18Z. Gusty winds may create UDDFS, lgt-ocnl mdt turbc and LLWS 12Z-18Z. KLAX...Good confidence in TAF. There is a 40 percent chc of 06006kt winds 11Z-18Z. KBUR...Good confidence in Cig/Vis fcst (SCT conds may not arrive until 09Z) There is a 30 percent chc of 06025g35kt winds 13Z-18Z. && .MARINE...30/819 PM. For the Outer Waters, moderate to high confidence in current forecast. High confidence in winds and seas remaining below Small Craft Advisory (SCA) levels today through at least Thursday for the waters north of the northern Channel Islands. For the waters south of the northern Channel Islands, high confidence in winds and seas remaining below SCA levels through tonight. On Tuesday, there is a 60% chance of SCA level northeast winds, especially across the eastern portion of the zone (PZZ676). For Tuesday night through Friday, high confidence in winds and seas remaining below SCA levels. For the Inner Waters north of Point Sal, high confidence in current forecast. Winds and seas will remain below SCA levels today through Friday. For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. For tonight through Tuesday morning, there is a 70% chance of SCA level easterly winds from Ventura south to Santa Monica. Short period, hazardous seas are expected to affect the inner waters during the timing of the strongest winds. Otherwise, winds and seas are expected to remain below SCA levels through Friday. There is a 50-60% chance of gusty winds reaching the front side of Avalon Harbor between 3 am and 10 am Tuesday. 15 to 25 knots with 3 to 5 foot wind waves are possible during this time. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory in effect until 6 PM PST Tuesday for zones 53-54-88-358-359-363-547. (See LAXNPWLOX). Hard Freeze Watch in effect from late Tuesday night through Wednesday morning for zone 59. (See LAXNPWLOX). Frost Advisory in effect from 1 AM to 8 AM PST Tuesday for zones 340-341-346-347-356-357. (See LAXNPWLOX). Freeze Watch in effect from late Tuesday night through Wednesday morning for zones 340-341-346-347-356-357. (See LAXNPWLOX). Wind Advisory in effect from 3 AM to 6 PM PST Tuesday for zones 354-355-362. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 9 AM PST Tuesday for zones 650-655-676. (See LAXMWWLOX). && $$ PUBLIC...Kittell/Rorke AVIATION...Rorke MARINE...Lund/RAT SYNOPSIS...RK weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox