985 FXUS66 KLOX 260303 AFDLOX SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 800 PM PDT SUN OCT 25 2015 .SYNOPSIS... HIGH PRESSURE ALOFT WILL SUPPORT WARM CONDITIONS THROUGH TUESDAY. LOW PRESSURE ALOFT WEDNESDAY INTO THURSDAY WILL INTRODUCE THE SLIGHT CHANCE OF SHOWERS AND COOLER TEMPERATURES. A RETURN TO WARMER WEATHER IS POSSIBLE NEXT WEEKEND AS POTENTIALLY GUSTY SANTA ANA WINDS DEVELOP IN THE WAKE OF THE LOW PRESSURE SYSTEM. && .UPDATE...OVERALL...A VERY QUIET EVENING ACROSS THE FORECAST DISTRICT. BASED ON SATELLITE...CIRRUS DECK HAS MOVED EASTWARD AND SKIES ARE CURRENTLY MOSTLY CLEAR. WITH WEAK OFFSHORE GRADIENTS OVERNIGHT...ANTICIPATE LITTLE STRATUS DEVELOPMENT...WITH ONLY THE CENTRAL COAST LIKELY TO SEE ANY AMOUNT OF STRATUS/FOG...AND THE PREDOMINANT SKY CONDITION WILL BE MOSTLY CLEAR. AS FOR WIND...THERE IS A LITTLE BIT OF NORTHERLY WINDS ACROSS SOUTHERN SANTA BARBARA COUNTY THIS EVENING...BUT THESE WINDS ARE EXPECTED TO REMAIN WELL BELOW ANY SORT OF ADVISORY THRESHOLDS. QUICK LOOK AT INITIAL 00Z MODEL DATA SHOWS NO MAJOR CHANGES TO PREVIOUS FORECAST THINKING. MOST SIGNIFICANT FORECAST ISSUE WILL CONTINUE TO BE THE POTENTIAL FOR SOME MODERATE NORTH TO NORTHEAST WINDS WEDNESDAY NIGHT THROUGH THE WEEKEND. OVERALL...JUST MINOR CHANGES TO THE FORECAST FOR THE IMMEDIATE SHORT TERM...BASICALLY JUST ADJUSTING SKY WORDING. REST OF THE FORECAST LOOKS IN GOOD SHAPE THIS EVENING. && *** FROM PREVIOUS DISCUSSION *** .SHORT TERM (TODAY-WED)...THE BACK EDGE OF THE HIGH LEVEL MOISTURE IS STARTING TO ENTER THE CWA FROM THE WEST AND ALL OF THE HIGH CLOUDS SHOULD BE EAST OF THE AREA BY MONDAY MORNING. CLOUDS HAD A SIGNIFICANT IMPACT ON TEMPS WITH HIGHS DOWN 5-10 DEGREES ON AVERAGE. WE SHOULD SEE A DECENT BOUNCE BACK IN HIGHS MONDAY WITH A FULL DAY OF SUNSHINE AND OTHERWISE SIMILAR PARAMETERS AS TODAY. SO LOOK FOR HIGHS MONDAY TO BE SIMILAR TO SLIGHTLY COOLER THAN SATURDAY IN MOST AREAS. ONSHORE TRENDS EXPECTED TO BEGIN TUESDAY BUT RIDGING ALOFT WILL KEEP TEMPS QUITE WARM WITH HIGHS ONLY A FEW DEGREES COOLER THAN MONDAY. SIGNIFICANT DIFFERENCES APPEAR IN THE MODELS ON WEDNESDAY, BUT MOST NOTABLY THE GFS WHICH IS THE ONLY OPERATIONAL MODEL MAINTAINING SOME TROPICAL CHARACTERISTICS OF OLAF AS IT GETS PICKED UP BY THE TROF OVER THE GULF OF ALASKA. BY WEDNESDAY MORNING THE SURFACE LOW OF WHAT'S LEFT OF OLAF IS ABOUT 300 MILES WEST OF PT CONCEPTION AND BY AFTERNOON IT'S JUST OUTSIDE OUR COASTAL MARINE BOUNDARY AS A 998 MB LOW. IT ALSO SHOWS LOW LVL SOUTHEAST WINDS 30-40 KT ACROSS THE OUTER PORTION OF ZONE PZ673. THIS A SIMILAR SOLUTION AS THE 06Z RUN BUT SLIGHTLY WEAKER AND FURTHER WEST. GIVEN THAT NONE OF THE OTHER MODELS ARE SUPPORTING THIS SCENARIO AM INCLINED TO LEAN CLOSER TO THE NAM/ECMWF SOLUTIONS WHICH BASICALLY SHOW A DRY INSIDE TROF PASSAGE WITH MINIMAL CHANCES FOR ANY PRECIPITATION. BEST CHANCES WOULD ACTUALLY COME BEHIND THE TROF WED NIGHT INTO EARLY THU WITH THE NORTH FLOW BEHIND IT POSSIBLY GENERATING SOME UPSLOPE SHOWERS ACROSS OUR BORDER WITH KERN COUNTY. WILL KEEP IN LOW POPS EVERYWHERE JUST IN CASE THE GFS IDEA PANS OUT, BUT EVEN THAT SOLUTION KEEPS THE BULK OF ANY PRECIPITATION TO OUR WEST. OVERALL A VERY LOW CONFIDENCE FORECAST WEDNESDAY. .LONG TERM (THU-SUN)...THE TROF PASSING THROUGH WEDNESDAY WILL EVOLVE INTO A CLOSED CIRCULATION EITHER OVER AZ OR NRN MEXICO BY FRIDAY MORNING. MOISTURE WILL WRAP AROUND THE LOW INTO THE EASTERN PORTION OF OUR FORECAST AREA, BUT AT THIS TIME IT LOOKS LIKE ANY PRECIP CHANCES WILL REMAIN EAST OF LOS ANGELES COUNTY. INCREASING NORTHERLY FLOW WILL BRING GUSTY WINDS TO SOME AREAS INCLUDING THE GRAPEVINE AND SRN SBA COUNTY, QUITE LIKELY ADVISORY LEVEL AND POSSIBLY WARNING LEVEL AT TIMES DEPENDING ON WHERE THE UPPER LOW SETS UP AND WHETHER THE JET WILL BE PROPERLY ALIGNED TO PROVIDE ADDITIONAL UPPER SUPPORT. TEMPS THU/FRI WILL BE COOLER THAN THEY HAVE BEEN BUT STILL ABOVE NORMAL FOR COAST/VALLEYS DUE TO THE SUBSIDENCE FROM THE NORTH WINDS. THEN WARMING UP GOING INTO THE WEEKEND AS THE LOW MOVES EAST AND RIDGING DEVELOPING ALONG WITH A SHIFT TO NORTHEAST WINDS AND POSSIBLY A MODERATE SANTA ANA EVENT. && .AVIATION...25/2250Z... AT 2212Z...THERE WAS A SURFACE-BASED INVERSION AT KLAX. THE TOP OF THE INVERSION WAS 1300 FEET WITH A TEMPERATURE OF 25 DEGREES CELSIUS. OVERALL...HIGH CONFIDENCE IN 00Z TAF PACKAGE. CIRRUS SHIELD IS PUSHING EASTWARD THIS AFTERNOON. WITH WEAK OFFSHORE FLOW EXPECTED TO PREVENT ANY STRATUS DEVELOPMENT...VFR CONDS ARE ANTICIPATED AT ALL SITES THROUGH THE PERIOD. KLAX...HIGH CONFIDENCE IN 00Z TAF. VFR CONDS WILL PREVAIL THROUGH THE PERIOD. KBUR...HIGH CONFIDENCE IN 00Z TAF. VFR CONDS WILL PREVAIL THROUGH THE PERIOD. && .MARINE...25/800 PM... MODERATE TO HIGH CONFIDENCE IN FORECAST OF SMALL CRAFT ADVISORY NORTHWEST WINDS OVER THE OUTER WATERS THROUGH LATE TONIGHT. THE STRONGER WINDS WILL BE OVER TWO NORTHERN OUTER ZONES. SCA GUSTS WILL PERSIST OVER THE NEARSHORE WATERS NORTH OF POINT SAL THROUGH LATE THIS EVENING...AND HAZARDOUS SHORT PERIOD SEAS WILL CONTINUE THROUGH LATE TONIGHT. MAINLY LIGHT WINDS ARE EXPECTED THROUGHOUT THE WATERS FROM MONDAY AFTERNOON THROUGH WEDNESDAY. NORTHWEST WINDS ARE FORECAST TO INCREASE WEDNESDAY NIGHT THROUGH FRIDAY...WITH GUSTS 30 TO 35 KNOTS. THERE IS A CHANCE THAT A GALE WARNING WILL BE NEEDED AT SOME POINT DURING THIS TIME PERIOD. MODERATE CONFIDENCE IN THIS FORECAST. STRONG GUSTS ARE EXPECTED ACROSS ALL PORTIONS OF THE WATERS. SWELLS FROM DIRECTIONS 290-300 AND FROM 230-250 WILL CREATE SCA FOR HAZARDOUS SEA CONDITIONS WEDNESDAY THROUGH THURSDAY NIGHT. && .LOX WATCHES/WARNINGS/ADVISORIES... SMALL CRAFT ADVISORY (SEE LAXMWWLOX). && $$ PUBLIC...MW/RAT AVIATION...RAT MARINE...30 SYNOPSIS...RM WWW.WEATHER.GOV/LOSANGELES