308 FXUS66 KLOX 131815 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 1015 AM PST Wed Feb 13 2019 .SYNOPSIS...13/912 AM. Rain, strong winds, and mountain snow will begin today, and should continue into Thursday. Rains will be heavy at times on Thursday, but lighter winds are expected. The chance for showers lingering through Sunday along with cooler temperatures. && .SHORT TERM (TDY-FRI)...13/1014 AM. Rain has begun across the area but so far mostly on the light side as the moisture is relying almost solely on orographics to lift it and create drops large enough to survive the fall to the surface. Radar returns look more impressive than what's being felt on the ground as drops fall through a drier layer, particularly in LA/Ventura counties where surface humidities are still under 50% in many areas. Conditions are a little more favorable for periods of moderate rain this afternoon across southern SB County and in upslope parts of LA/Ventura counties but elsewhere expect rain to remain pretty light through early Thursday. The second burst coming tomorrow definitely looks more impressive than today. PW's will be highest across southeast LA County but periods of moderate to heavy rain are possible everywhere west and south of the mountain peaks. Models aren't looking quite as convective tomorrow as they did yesterday but better dynamics and more available moisture will create much higher rain rates. At this point it looks like the first year burns will be at risk for limited debris flows while rates likely won't be high enough for significant issues in other areas. There's still some colder air trapped in the lower layers keeping snow levels between 5000 and 6000 ft with minimal accumulations, but these will be rising rapidly through the day and by tonight snow levels will be above 9000' and remain that way through most of Thursday. ***From previous discussion*** An impressive south to north pressure gradient has set up today. The KLAX to KSFO pressure gradient is already an strong 9.6 mb and is forecast to reach 14 mb later this morning. This gradient will bring strong advisory level winds to all of the coasts and vlys of SLO and SBA county. This gradient will also bring warning level gusts of 60 mph to the mtns of SLO/SBA/VTA counties. These winds will persist with a few brief lulls through Thursday afternoon. There will be a slight lull in the action for the coasts and vlys later tonight as the flow turns briefly anticyclonic. The low level sfc flow remains southerly so the coastal foothills and slopes should continue to see steady light to moderate rain. Rainfall totals from tonight through Thursday evening at this time look like .75" to 1.50 inches across the coasts and vlys. The coastal slopes will see another 1 to inches of rainfall and the big winner will be the eastern San Gabriels where 2 to 4 inches will fall. All told the csts/vlys will see an inch to 2.5 inches of rain...3 to 4 inches will likely fall across the coastal slopes and if the plume does shift south the eastern San Gabriels will see 3 to 5 inches of rain. Friday once looked like it was going to be showery but more dry than wet. This no longer look like the case as moist cyclonic flow will bring a fair amount of clouds and showers. These showers will not produce much in the way of rainfall totals but everyone will need to keep their umbrellas close. .LONG TERM (SAT-TUE)...13/314 AM. Colder cyclonic flow will continue over the weekend. There is a chc of a shower anywhere at any time but the best chances will be over SLO and nrn SBA counties as well as the north facing mountain slopes. There looks like a little trof will move through the area on Sunday which will make it the wetter day of the two. It will be cool and snow levels will fall to as low as 2000' by Sunday night. There is not much moisture to work with so rainfall (and snowfall) totals will not be that impressive more in the nuisance category than anything. Two pretty cool days with max temps across the coasts and vlys near 60 on Sat and a rather chilly 55 on Sunday. Drying and clearing slated for Mon and Tue as drier air moves into the state. Still cool, however with cstl/vly highs still many degrees blo normal. && .AVIATION...13/1209Z. At 12Z at KLAX...there was a moist layer up to 10k ft. Low to moderate confidence in 12z TAFs as cigs and vis will vary frequently once the rain starts. Lower confidence beginning immediately for terminals N of Point Conception. Confidence will lower after 18z for areas S of Point Conception as rain fills in. Cigs will mostly range from 015 to 030 with some BKN008 during the heavier rain. Good confidence in winds forecast. KLAX...Good confidence in 12z TAF through 17Z and then moderate confidence. Cigs and vis will vary frequently once the rain starts. Cigs will mostly range from 015 to 030 with some BKN008 during the heavier rain. Moderate confidence in winds forecast with a 40 percent chc of 10012kt from 16Z-21Z. WInds will persist out of the east through the 30-hour TAF period. KBUR...Good confidence in 12z TAF through 17Z and then moderate confidence. Cigs and vis will vary frequently once the rain starts. Cigs will mostly range from 015 to 030 with some BKN008 during the heavier rain. && .MARINE...13/958 AM. Southeast to south winds were increasing across the coastal waters early this morning as a vigorous cold front approaches the area. High confidence for Gales across the two northern outer zones, the nearshore waters off the Central Coast, and over the western Santa Barbara Channel. There is a 40% chance of gales across the inner Santa Barbara Channel, as well as the southern inner and outer waters west of L.A. County. Gusts between 35 and 45 mph are likely across the areas under a Gale Warning during this time. SCA winds will spread across the remainder of the waters this morning. Very dangerous seas are expected as short period large south wind waves combine with a building medium period northwest swell. A secondary frontal boundary is expected on Thursday with another round of potential Gales across the outer waters, and possible the inner waters as well. Still too soon for a high confidence factor for the strength of winds, but will continue to monitor. There will be another larger swell moving into the coastal waters by this weekend. && .BEACHES...13/353 AM. Developing southerly winds across the coastal waters between today through Thursday could bring elevated surf up to 6 feet due to short period southerly wind swells piling up across some south facing beaches. There will be strong rip currents at areas beaches as well. A larger northwest swell is possible for this weekend, which could develop high surf at Central Coast beaches between Friday night and Sunday. Confidence is still low this far out with timing and the potential surf heights. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory in effect until 3 PM PST Thursday for zones 34>39-54. (See LAXNPWLOX). High Wind Warning in effect until 3 PM PST Thursday for zones 51>53. (See LAXNPWLOX). PZ...Gale Warning in effect until 3 PM PST Thursday for zones 645-670-673. (See LAXMWWLOX). Gale Warning in effect until 3 AM PST Thursday for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 9 PM PST Thursday for zones 655-676. (See LAXMWWLOX). && .HAZARD POTENTIAL OUTLOOK (FRI-TUE). Low elevation snow is possible Friday and again Sunday potentially creating impacts on Interstate 5 and other roads through the mountains. && $$ PUBLIC...MW/Rorke AVIATION...CK MARINE...Sweet BEACHES...Kaplan SYNOPSIS...Phillips weather.gov/losangeles