765 FXUS66 KLOX 171001 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 201 AM PST Fri Jan 17 2020 .SYNOPSIS...17/200 AM. Today through Sunday, high pressure will build over the area while weak northeasterly flow develops near the surface. This will result in dry and warmer conditions through Sunday with locally gusty winds. For early next week, cloudy and cooler conditions are expected with a chance of light showers. && .SHORT TERM (TDY-SUN)...17/201 AM. Overall, 00Z models in good synoptic agreement through the short-term period. At upper levels, ridge will develop over the area today and Saturday then will weaken slightly on Sunday. Near the surface, offshore flow will increase, peaking in strength by Sunday morning. Forecast-wise, cold front, and associated rain, has moved out of LA county, leaving behind some partly cloudy skies and patchy fog. Expect clouds to decrease through the day, resulting in a mostly sunny sky condition while fog dissipates by mid morning. With more sunshine today and higher thicknesses/H5 heights, temperatures will be several degrees warmer. For tonight through Sunday, models indicate a rather significant amount of high level moisture. This should translate into a decent amount of high clouds through Sunday, warranting a partly to mostly cloudy sky condition. Offshore surface gradients will be increasing, with LAX-DAG peaking between -4.0 and -5.3 mb by Sunday morning. Upper level winds and thermal support is not too impressive, so do not anticipate any widespread advisory-level northeast winds. However, there will likely be some local advisory level gusts on Sunday morning in the mountains of Ventura and Los Angeles counties. With the ridge building overhead and offshore gradients, temperatures will be warming Saturday and Sunday. If the high clouds are thinner than anticipated, high temperatures could be a few degrees higher than currently forecast. .LONG TERM (MON-THU)...17/200 AM. For extended, no major changes to previous thinking. For Monday and Tuesday, an upper level trough will move across the West Coast, entraining varying amounts of mid to high level moisture (with GFS more robust than the ECMWF). So, likely partly to mostly cloudy skies for the area. Will keep with the idea of some chance/slight chance of showers Monday and Tuesday although any precipitation that develops will be very light. With anticipated cloud cover and weak onshore flow, temperatures should cool a couple degrees both Monday and Tuesday. For Wednesday and Thursday, upper level ridge will build off the West Coast while gradients turn weakly offshore by Thursday. So, will expect high level moisture to diminish with mostly clear skies prevailing. Temperatures should exhibit a slight warming trend with building ridge and surface gradient trends. && .AVIATION...17/0602Z. At 0530Z at KLAX, there was a 9000 ft deep moist layer. Low confidence in TAFs through 18Z then good confidence. Cigs/Vis will vary frequently through 09Z as front rolls through. There is a 30 percent chance that LIFR/IFR cigs will form a few hours after the rain stops and persist through mid morning. KLAX...Low confidence in TAF through 18Z then good confidence. Cigs/Vis will vary frequently through 09Z. There is a 30 percent chance of LIFR/IFR cigs 11Z-16Z. There is a 20 percent chc of an 6 kt east wind component through 10Z. KBUR...Low confidence in TAF through 18Z then good confidence. Cigs/Vis will vary frequently through 09Z. There is a 30 percent chance of LIFR/IFR cigs 11Z-16Z. && .MARINE...16/1253 PM. A storm system will impact the area into Friday. A cold front has moved into the Central Coast this afternoon, and will push south of Point Conception by this evening, and through Orange County by around midnight. Gusty south to southwest winds will affect the area near the front, with gusty west to northwest winds after the front passes. Gale Force winds were observed off the Central Coast, but winds now should not exceed Small Craft Advisory (SCA). All other waters should see winds near SCY at times into Friday. Moderate confidence in all hazards. Expect short period seas on top of the moderately long period swell, especially around and after the frontal passage. No thunderstorms are expected with this system, but enhanced cells near the cold front could produce thunderstorm- like conditions with strong gusty. Moderate confidence if winds staying below SCA to follow through the weekend. There is a potential for a large long period northwest to west swell affecting the area Tuesday and Wednesday. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...Small Craft Advisory in effect until 3 AM PST early this morning for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 5 AM PST early this morning for zones 650-655. (See LAXMWWLOX). Small Craft Advisory in effect until 9 AM PST this morning for zones 670-673-676. (See LAXMWWLOX). && .HAZARD POTENTIAL OUTLOOK (SUN-THU). No significant hazards expected. && $$ PUBLIC...Thompson AVIATION...Rorke MARINE...Kittell SYNOPSIS...RAT weather.gov/losangeles