373  
FXUS66 KLOX 021732  
AFDLOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA  
932 AM PST FRI DEC 2 2016  
   
SYNOPSIS
 
 
MODERATE TO STRONG SANTA ANA WINDS WILL FLOW THROUGH PORTIONS OF  
VENTURA AND LOS ANGELES COUNTIES THROUGH SATURDAY. PORTIONS OF  
SANTA BARBARA COUNTY WILL HAVE BREEZY WINDS. TEMPERATURES WILL BE  
BELOW NORMAL FOR AT LEAST THE NEXT WEEK BUT WILL WARM SLIGHTLY  
DURING THE NEXT FEW DAYS WITH SUNDAY AS THE WARMEST DAY.  
 

 
   
SHORT TERM
 
(TDY-SUN)  
 
THE MAIN STORY FOR THE NEXT COUPLE DAYS WILL BE THE STRONG WINDS  
EXPECTED ACROSS MUCH OF LOS ANGELES AND VENTURA COUNTIES. A 1035  
MB SURFACE HIGH WILL DEVELOP OVER NORTHERN NEVADA BEHIND AN  
INSIDE SLIDER THAT MOVED OVER THE FORECAST AREA YESTERDAY. WHAT  
WILL DRIVE THIS STRONGER AND COLDER EVENT WILL BE THE UPPER LEVEL  
PATTERN SET UP. A COLD UPPER LEVEL TROUGH WILL DROP SOUTH FROM  
THE GREAT BASIN INTO NORTHERN BAJA THIS MORNING. THE POSITION OF  
THE UPPER LOW WILL BE CONDUCIVE FOR BRINGING GOOD UPPER LVL SUPPORT  
FROM 850 MB TO 500 MB OF NORTH TO NORTHEAST FLOW. ALSO, THE COLDER  
DENSE AIR FROM THE LOW WILL BRING ADDITIONAL SUBSIDENCE OVER THE  
AREA. THEREFORE BESIDES BEING A COOLER SANTA ANA IT SHOULD BE MORE  
WIDESPREAD AFFECTING MORE AREAS. HIGH WIND WARNINGS ARE IN EFFECT  
FOR THE LA/VTU COUNTY MOUNTAINS AND SANTA CLARITA VALLEY, AND ALSO  
ADDED THE VENTURA COUNTY VALLEYS WHERE GUSTS TO 60 MPH AND OR  
SUSTAINED WINDS OF 40 MPH WILL BE STRONGEST ACROSS THE EASTERN  
PORTION. THE NW PORTION OF THE SAN FERNANDO VALLEY INCLUDING  
NORTHRIDGE TO CHATSWORTH COULD SEE LOCAL GUSTS TO 60 MPH AS WELL  
LATE THIS MORNING INTO THIS AFTERNOON. WILL BE ADDING A WIND  
ADVISORY FOR CATALINA ISLAND AS WELL. AVALON HARBOR COULD BE  
AFFECTED WITH CHOPPY SEAS FROM THE OFFSHORE WINDS MAKING IT  
DIFFICULT FOR BOATS IN THE HARBOR. UNLIKE MOST SANTA ANA WINDS,  
THIS ONE WILL ACTUALLY STRENGTHEN AS WE GO THROUGH THIS  
AFTERNOON...BEFORE WINDS DIMINISH SOME LATE THIS AFTERNOON OR  
EARLY EVENING. WINDS WILL THEN RESTRENGTHEN AGAIN TONIGHT INTO  
SATURDAY MORNING. THERE WILL CONTINUE TO BE GOOD COLD AIR  
ADVECTION TONIGHT TO HELP WINDS REMAIN FAIRLY STRONG, WHILE THE  
UPPER LEVEL PATTERN WEAKENS SLIGHTLY AS THE LOW MOVES FURTHER SE  
OVER MEXICO. OFFSHORE WINDS WILL CONTINUE INTO SUNDAY MORNING, BUT  
WILL BE MUCH WEAKER AND LESS WIDESPREAD. THE UPPER LEVEL SUPPORT  
WILL NOT BE A FACTOR. THERE IS STILL A CHANCE THAT A FEW LOW END  
WIND ADVISORIES MIGHT BE NEEDED FOR THE USUAL WIND PRONE AREAS OF  
LA/VTU COUNTIES.  
 
GUSTY OFFSHORE WINDS WILL ALSO CONTINUE ACROSS THE CENTRAL COAST  
FROM THE SAN LUCIA MTNS THROUGH THE SUNDAY. WINDS WILL BE MUCH  
WEAKER COMPARED TO LA/VTU COUNTIES.  
 
RED FLAG WARNINGS ARE ALSO IN PLACE DURING THE HIGH WIND EVENT.  
READ THE FIRE WEATHER DISCUSSION BELOW FOR MORE DETAILS.  
 
AS FAR AS TEMPS...TODAY WILL BE MUCH COOLER ACROSS INTERIOR AREAS  
WHILE COAST AND COASTAL VALLEYS WILL BE 2-4 DEGREES COOLER WITH  
HIGHS ONLY REACHING THE MID 60S, WHILE INLAND VALLEYS AND THE  
ANTELOPE VALLEY REMAIN COOL IN THE UPPER 40S TO MID 50S. MUCH  
COOLER IN THE MOUNTAINS. FOR SATURDAY, THE AIR MASS WILL MODIFY A  
BIT WARMER AND THAT WILL TRANSLATE TO HIGHS 3-7 DEGREES WARMER,  
YET WILL STILL ONLY REACH THE MID TO UPPER 60S WITH A FEW 70S FOR  
WARMEST LA/VTU VALLEYS. STILL MUCH COOLER INLAND. HIGHS WILL EVEN  
WARMER ON SUNDAY AS HIGH PRESSURE ALOFT NUDGES IN FROM THE WEST  
AND WEAKER OFFSHORE FLOW EXPECTED. HIGHS WILL BUMP UP AN  
ADDITIONAL 3-6 DEGREES IN MOST AREAS WITH INLAND AREAS SEEING THE  
BEST WARMUP. HIGHS WILL BE WARMEST VALLEYS WILL BE IN THE LOWER TO  
MID 70S WITH 60S IN MOST ALL OTHER AREAS...EXCEPT FOR THE  
MOUNTAINS WHICH TO NO SURPRISE WILL BE MUCH COOLER.  
   
LONG TERM
 
(MON-THU)  
 
THE UPPER RIDGE THAT IS EXPECTED OVER THE REGION ON SUNDAY WILL BE  
SHORT LIVED AS ANOTHER TROUGH WITH AN INSIDE SLIDER DROPS INTO  
THE GREAT BASIN EARLY NEXT WEEK. MODELS HAVE BACKED OFF ANY CHANCE  
OF PRECIP TO THE NORTHERN PORTION OF THE FORECAST AREA. THE TROUGH  
WILL BRING COOLER TEMPS RANGING 4-10 DEGREES COOLER WITH ONSHORE  
FLOW ACROSS COAST AND VALLEYS. MORE NORTHERLY WINDS WILL DEVELOP  
ACROSS SBA MTNS, I-5 CORRIDOR AND ANTELOPE VALLEY WILL DEVELOP AS  
THE TROUGH PASSES TO OUR EAST MONDAY NIGHT INTO TUE BOTH MODELS  
SHOW AN UPPER LEVEL RIDGE BUILDING OVER THE STATE AROUND MID WEEK  
FOR A WARMING TREND WITH PROLONGED WEAK/MODERATE OFFSHORE FLOW.  
 

 
   
AVIATION...02/1600Z
 
 
AT 1550Z, THERE WAS NO MARINE INVERSION AT KLAX.  
 
THROUGH THE TAF PERIOD, VFR CONDITIONS WILL CONTINUE FOR ALL TAF  
SITES. STRONG NORTHEAST FLOW THROUGH THE PERIOD WILL CREATE GUSTY  
SURFACE WINDS (ESPECIALLY ACROSS VENTURA AND LOS ANGELES  
COUNTIES). ADDITIONALLY, THERE WILL BE AREAS OF MODERATE LLWS AND  
TURBULENCE.  
 
KLAX...HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE PERIOD.  
MODERATE CONFIDENCE IN WIND FORECAST AS THERE IS A 40% CHANCE OF  
NORTH TO NORTHEAST WINDS EXCEEDING 10 KNOTS THROUGH THIS  
AFTERNOON AND AGAIN SATURDAY MORNING. LLWS WILL BE LIKELY THROUGH  
TONIGHT.  
 
KBUR...HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE PERIOD.  
MODERATE CONFIDENCE IN WIND FORECAST AS GUSTY NORTHERLY WINDS WILL  
ERRATICALLY SURFACE THROUGH THIS EVENING. LLWS AND TURBULENCE WILL  
BE ISSUES THROUGH THE TAF PERIOD.  
 

 
   
MARINE...02/800 AM
 
 
FOR THE OUTER WATERS, MODERATE TO HIGH CONFIDENCE IN CURRENT  
FORECAST. HIGH CONFIDENCE IN SMALL CRAFT ADVISORY (SCA) LEVEL  
WINDS CONTINUING THROUGH TONIGHT, EXCEPT THROUGH SATURDAY  
AFTERNOON ACROSS EASTERN SECTIONS OF THE SOUTHERN OUTER WATERS.  
WINDS WILL FLIRT WITH SCA LEVELS THROUGH SUNDAY THEN LIKELY  
INCREASE TO SCA LEVELS SUNDAY NIGHT THROUGH TUESDAY.  
 
FOR THE INNER WATERS, MODERATE TO HIGH CONFIDENCE IN CURRENT  
FORECAST. FOR THE WATERS NORTH OF POINT SAL, WINDS AND SEAS ARE  
EXPECTED TO REMAIN BELOW SCA LEVELS THROUGH TUESDAY. FOR THE  
WATERS SOUTH OF POINT CONCEPTION, HIGH CONFIDENCE IN GALE FORCE  
WINDS THROUGH THIS EVENING WITH SCA LEVEL WINDS EXPECTED TONIGHT  
AND SATURDAY. THE STRONGEST WINDS WILL OCCUR FROM VENTURA TO SANTA  
MONICA (OUT TO ANACAPA AND SANTA CRUZ ISLANDS) AND THROUGH THE SAN  
PEDRO CHANNEL (OUT TO CATALINA ISLAND).  
 

 
   
FIRE WEATHER
 
02/900 AM.  
 
STRONG UPPER LEVEL FLOW COUPLED WITH HIGH PRESSURE OVER THE GREAT  
BASIN WILL CONTINUE TO PRODUCE A STRONG SANTA ANA WIND EVENT TO  
LOS ANGELES AND VENTURA COUNTIES THROUGH SATURDAY. THOUGH MUCH OF  
THE AREA HAS RECEIVED AROUND 1 INCH OF RAIN OVER THE LAST TWO  
WEEKS, THE VEGETATION (FUELS) REMAIN RECEPTIVE TO LARGE FIRE  
GROWTH UNDER RED FLAG WEATHER CONDITIONS.  
 
OVER THE COASTAL AND VALLEY AREAS (INCLUDING THE SANTA MONICA  
MOUNTAINS), HUMIDITIES WILL GENERALLY LOWER INTO THE 10 TO 15  
PERCENT RANGE TODAY AND 8 TO 12 PERCENT RANGE ON SATURDAY.  
RED FLAG CONDITIONS ARE EXPECTED THIS AFTERNOON THROUGH SATURDAY  
AFTERNOON AS A RESULT. RED FLAG WARNINGS ARE IN EFFECT FOR  
COASTAL AND VALLEY AREAS OF VTU AND L.A. COUNTIES THROUGH SAT  
EVENING.  
 
OVER THE MOUNTAINS, THE COLD TEMPERATURES WILL KEEP RELATIVE  
HUMIDITIES GENERALLY ABOVE 20 PERCENT TODAY, BUT SHOULD LOWER  
INTO THE 10 TO 20 PERCENT RANGE ON SATURDAY. AS A RESULT, THE  
MOUNTAINS WILL NOT HAVE A RED FLAG WARNING TODAY (THOUGH THERE IS  
AN ELEVATED RISK WITH THE STRONG WINDS) BUT THE LOS ANGELES COUNTY  
MOUNTAINS WILL BE UNDER A WARNING ON SATURDAY. WITH WEAKER WINDS  
AND THE SAME HUMIDITY ISSUES, THE VENTURA COUNTY MOUNTAINS WILL  
REMAIN OUT OF THE RED FLAG WARNING.  
 
THOSE HANDLING POTENTIAL FIRE IGNITION SOURCES MUST EXERCISE  
EXTRA CAUTION AS EXTREME FIRE BEHAVIOR AND RAPID FIRE GROWTH IS  
EXPECTED IF ANY FIRE WERE TO BE STARTED. THIS INCLUDES THOSE  
LIGHTING FIRES FOR WARMTH CONSIDERING THE COLD CONDITIONS.  
 

 
   
LOX WATCHES/WARNINGS/ADVISORIES
 
 
CA...FREEZE WATCH IN EFFECT FROM LATE TONIGHT THROUGH SATURDAY  
MORNING FOR ZONE 37. (SEE LAXNPWLOX).  
WIND ADVISORY IN EFFECT UNTIL 2 PM PST SATURDAY FOR ZONES  
40-41-87-547. (SEE LAXNPWLOX).  
HIGH WIND WARNING IN EFFECT UNTIL 2 PM PST SATURDAY FOR ZONES  
44>46-53-54-88. (SEE LAXNPWLOX).  
WIND ADVISORY IN EFFECT UNTIL 6 PM PST THIS EVENING FOR ZONE  
59. (SEE LAXNPWLOX).  
RED FLAG WARNING IN EFFECT UNTIL 6 PM PST SATURDAY FOR ZONES  
240-241-244>246-288-547-548. (SEE LAXRFWLOX).  
RED FLAG WARNING IN EFFECT FROM 6 AM TO 6 PM PST SATURDAY FOR  
ZONE 254. (SEE LAXRFWLOX).  
PZ...GALE WARNING IN EFFECT UNTIL 9 PM PST THIS EVENING FOR ZONES  
650-655. (SEE LAXMWWLOX).  
SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PST SATURDAY FOR  
ZONES 670-673. (SEE LAXMWWLOX).  
SMALL CRAFT ADVISORY IN EFFECT UNTIL 2 PM PST SATURDAY FOR  
ZONE 676. (SEE LAXMWWLOX).  
 

 
   
HAZARD POTENTIAL OUTLOOK
 
(SUN-THU)  
NO SIGNIFICANT HAZARDS EXPECTED.  
 

 
 

 
 
PUBLIC...KAPLAN  
AVIATION...RAT  
MARINE...RAT  
FIRE...KITTELL  
SYNOPSIS...KJ  
 
WEATHER.GOV/LOSANGELES  
 
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