849  
FXUS66 KLOX 011731  
AFDLOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA  
1031 AM PDT SAT OCT 1 2016  
   
SYNOPSIS
 
 
TWO UPPER LEVEL TROUGHS WILL BRING INCREASINGLY COOL AND BREEZY  
CONDITIONS TO THE REGION EARLY THIS WEEK, WITH TEMPERATURES DOWN  
TO BELOW NORMAL LEVELS TODAY. IT WILL REMAIN COOL ON MONDAY, THEN  
UPPER LEVEL RIDGING WILL PRODUCE A WARMING TREND THROUGH MID WEEK,  
WITH ABOVE NORMAL TEMPERATURES IN MOST AREAS WEDNESDAY THROUGH  
FRIDAY.  
 

 
   
SHORT TERM
 
(TDY-MON)  
 
SKIES ARE MOSTLY CLEAR ACROSS THE REGION THIS MORNING. GUSTY  
WINDS ACROSS SOUTHERN SANTA BARBARA COUNTY HAVE DIMINISHED TO LESS  
THAN 20 MPH IN MOST AREAS. BY AND LARGE TEMPERATURES ARE DOWN 3 TO  
5 DEGREES THIS MORNING EXCEPT FOR THOSE AREAS OF THE CENTRAL COAST  
WHICH WERE COOLED BY FOG AND LOW STRATUS YESTERDAY MORNING. PISMO  
BEACH IS UP 14 DEGREES FROM ITS FOGGY START YESTERDAY.  
 
*** FROM PREVIOUS DISCUSSION ***  
 
HEIGHTS WILL CONTINUE TO FALL ACROSS THE REGION TODAY AS THE  
UPPER TROUGH EXTENDING SOUTHWARD FROM AN UPPER LOW OFF THE OREGON  
COAST PUSHES TOWARD THE REGION. WITH FALLING HEIGHTS, COOLING AT  
850 MB AND 950 MB AND INCREASING W-E ONSHORE GRADIENTS, EXPECT  
SEVERAL DEGREES OF COOLING IN MOST AREAS TODAY. STILL, THE WARMEST  
LOCATIONS IN THE VALLEYS OF L.A. AND VTU COUNTIES COULD HAVE HIGHS  
CLOSE TO 90 DEGREES TODAY, BUT MOST VALLEY LOCATIONS WILL HAVE  
HIGHS IN THE 80S. GOOD N-S GRADIENTS WILL LIKELY PRODUCE SOME  
WARMING IN COASTAL AREAS OF SLO AND SBA COUNTIES TODAY. ALSO,  
EXPECT SOME GUSTY NORTHWEST WINDS THIS AFTERNOON ON THE CENTRAL  
COAST, IN THE SLO COUNTY VALLEYS, AND ACROSS THE SOUTH COAST OF  
SBA COUNTY FROM REFUGIO WESTWARD. AT THIS POINT, EXPECT WINDS TO  
REMAIN JUST BELOW ADVISORY LEVELS, BUT THEY WILL BE CLOSE, AND IT  
WOULD NOT BE A SURPRISE IF ADVISORIES ARE NEEDED IN SOME AREAS.  
 
GUSTY NORTHWEST TO NORTH WINDS WILL AFFECT THE SANTA YNEZ RANGE  
AND THE ADJACENT SOUTH COAST OF SBA COUNTY BELOW PASSES AND  
CANYONS THIS EVENING AND EARLY TONIGHT. IT COULD BE A MARGINAL  
WIND ADVISORY EVENT TONIGHT.  
 
THE UPPER LOW OFF THE COAST OF OREGON WILL BE REPLACED BY A STRONGER  
ELONGATED UPPER LOW DROPPING SOUTHWARD THROUGH THE EASTERN PACIFIC.  
THIS UPPER LOW WILL BE LOCATED JUST OFF THE OREGON COAST EARLY  
SUNDAY MORNING, WITH A RATHER SHARP TROUGH EXTENDING SOUTHWARD.  
THE WRF SUGGESTS THAT LOW CLOUDS MAY BE PATCHY IN NATURE NORTH OF  
PT CONCEPTION, BUT IT DOES SHOW AN EDDY CIRCULATION DEVELOPING  
TONIGHT ACROSS THE SANTA MONICA BASIN, WITH LOW CLOUDS IN COASTAL  
SECTIONS OF L.A. COUNTY, SPREADING INTO COASTAL SECTIONS OF VTU  
COUNTY LATE TONIGHT. ALSO, WITH THE MARINE LAYER DEEPENING, SOME  
CLOUDS WILL PROBABLY PUSH INTO AT LEAST THE SAN GABRIEL VALLEY  
LATE TONIGHT. INCREASINGLY MOIST AND CYCLONIC LOW LEVEL FLOW  
ACROSS L.A. AND VTU COUNTIES COULD ALLOW FOR SOME DRIZZLE LATE  
TONIGHT/SUNDAY MORNING.  
 
THE TROUGH AXIS WILL SWING ACROSS CA DURING THE DAY SUNDAY. THE  
SOUTHERN END OF RAIN ASSOCIATED WITH A FRONTAL SYSTEM COULD GET  
RATHER CLOSE TO SLO COUNTY ON SUNDAY. THE WRF SHOWS CLOUDS  
LINGERING AT THE BEACHES OF L.A. AND VTU COUNTIES WELL INTO THE  
AFTERNOON ON SUNDAY. IT WILL BE MUCH COOLER ACROSS THE ENTIRE  
REGION ON SUNDAY, WITH MAX TEMPS WELL BELOW NORMAL IN MOST AREAS.  
 
INCREASING W TO NW FLOW ALOFT AND DECENT SUBSIDENCE SPREADING OVER  
THE REGION LATE SUNDAY SHOULD BRING GUSTY TO POSSIBLY ADVISORY  
LEVELS WEST WINDS TO THE ANTELOPE VALLEY AND NORTHWEST WINDS TO  
THE CENTRAL COAST SUNDAY AFTERNOON AND EVENING. EXPECT A RATHER  
STRONG NORTHWEST TO NORTH WIND EVENT ACROSS THE SANTA YNEZ RANGE  
AND THE ADJACENT SOUTH COAST OF SBA COUNTY SUNDAY EVENING, AND  
WIND ADVISORIES WILL LIKELY BE NEEDED. GUSTY NW TO N WINDS WILL  
DEVELOP ACROSS THE INTERSTATE 5 CORRIDOR SUNDAY NIGHT, AND THEY  
MAY ALSO REACH ADVISORY LEVELS. THE NORTH WINDS WILL SPREAD INTO  
THE WESTERN AND NORTHERN PORTIONS OF THE L.A. COUNTY VALLEYS, THE  
SANTA MONICAS, AND COASTAL SECTIONS OF L.A. COUNTY BELOW PASSES  
AND CANYONS FROM MALIBU TO THE HOLLYWOOD HILLS LATE SUNDAY NIGHT  
INTO MON MORNING. MOIST UPSLOPE NORTHERLY FLOW COULD BRING A FEW  
SHOWERS TO THE NORTHERN SLOPES OF THE VTU AND POSSIBLY FAR  
NORTHWESTERN L.A. COUNTY MOUNTAINS SUNDAY NIGHT/MON MORNING, WITH  
SNOW SHOWERS ABOVE 6500 FEET OR SO. THE STRATUS PATTERN WILL  
LIKELY BE PATCHY IN NATURE AS THE MARINE INVERSION WEAKENS. MONDAY  
WILL BE A RATHER CHILLS DAY ACROSS MOST OF THE REGION, WITH MAX  
TEMPS WELL BELOW NORMAL.  
 
   
LONG TERM
 
(TUE-FRI)  
 
THE UPPER TROUGH WILL MOVE EASTWARD TUE AND WED AND AN UPPER HIGH  
WILL BUILD INTO THE REGION. WEAK OFFSHORE FLOW SHOULD KEEP SKIES  
CLEAR. THERE WILL A SIGNIFICANT WARMING TREND TUE AND WED, WITH  
TEMPS BACK TO ABOVE NORMAL LEVELS BY WED, THEN SIMILAR TEMPS ARE  
EXPECTED ON THU AND FRI.  
 

 
   
AVIATION...01/1800Z
 
 
A MID/UPPER LEVEL TROUGH OF LOW PRESSURE UPSTREAM WILL MOVE OVER  
THE AREA. UPPER LEVEL STRONG SOUTHWEST WINDS WILL BECOME MODERATE  
TO STRONG WEST-SOUTHWEST BY 02/00Z WHILE MID LEVEL LIGHT TO  
MODERATE SOUTHWEST WINDS BECOME MODERATE WEST AFTER 02/20Z OVER  
THE AREA. WEAK ONSHORE PRESSURE GRADIENT THROUGH 02/02Z AND  
MODERATE AFTER 02/20Z OTHERWISE WEAK TO MODERATE NORTHERLY  
GRADIENT. BASE OF A WEAK CAPPING MARINE INVERSION WAS  
APPROXIMATELY .8KFT THIS MORNING WITH ISOLATED CLOUD FIELD OVER  
THE SAN PEDRO BASIN THIS MORNING. THE INVERSION BASE WILL DIFFER  
LITTLE AND CLOUD FIELD MAY BECOME SCATTERED TO BROKEN OVER THE  
BIGHT SUNDAY MORNING.  
 
MARINE LAYER AT LAX AT 1500Z IS 810 FEET DEEP AND THE INVERSION  
TOP IS AT 1533 FEET WITH A TEMP OF 21.2 DEGREES C.  
 
KLAX...CHANCE CIGS 006 AND VSBY 4SM BR BETWEEN 02/12-02/16Z.  
 
KBUR...VIRTUALLY CERTAIN CURRENT SKY/VSBY CONDITIONS WILL  
PERSIST.  
 
VIRTUALLY CERTAIN - 95-100%  
VERY LIKELY - 80-95%  
LIKELY - 60-80%  
CHANCE - 30-60%  
VERY UNLIKELY - 20% OR LESS  
 

 
   
MARINE...01/900 AM
 
 
NORTHWEST WIND WITH SMALL CRAFT ADVISORY CONDITIONS WILL CONTINUE FROM  
PIEDRAS BLANCAS TO SAN NICOLAS ISLAND THROUGH NEXT WEEK TUESDAY. OCCASIONAL  
GALE FORCE GUSTS ARE EXPECTED EACH AFTERNOON THROUGH SUNDAY. THE  
GALES FORCE GUSTS MAY BECOME FREQUENT SOUTH OF THE NORTHERN  
CHANNEL ISLANDS SUNDAY NIGHT THROUGH MONDAY AND A GALE WATCH IS  
IN EFFECT. NORTHWEST WINDS WILL LIKELY FILL IN OVER PORTIONS OF  
THE INNER BASINS EACH AFTERNOON THROUGH MONDAY. THERE WILL LIKELY  
BE A LULL IN THE WIND FOR SEVERAL HOURS AFTER SUNRISE THROUGH  
TUESDAY BUT SMALL CRAFT ADVISORY FOR HAZARDOUS SEA CONDITIONS WILL  
LIKELY EXIST.  
 

 
   
FIRE WEATHER
 
 
01/930 AM.  
GUSTY SUNDOWNER WINDS WITH ELEVATED FIRE DANGER WILL IMPACT THE  
SANTA BARBARA SOUTH COAST AND SANTA YNEZ MOUNTAINS DURING THE LATE  
AFTERNOON AND NIGHTTIME HOURS THROUGH TUESDAY NIGHT. FOR TONIGHT,  
WIND GUSTS OF 30 TO 40 MPH WILL MOSTLY BE CONFINED TO THE COASTAL  
AND FOOTHILL AREAS WEST OF GOLETA (ESPECIALLY IN THE HILLS ABOVE  
REFUGIO). ON SUNDAY NIGHT AND MONDAY NIGHT, THE WINDS ARE  
EXPECTED TO BE STRONGER (PEAKING BETWEEN 40 AND 50 MPH IN THE  
FOOTHILLS) AND MORE WIDESPREAD DUE TO INCREASED UPPER LEVEL WIND  
AND THERMAL SUPPORT. ON SUNDAY NIGHT, THE SANTA BARBARA-SANTA  
MARIA GRADIENT IS EXPECTED TO PEAK AROUND -4.5 MB. IT APPEARS THAT  
HUMIDITIES WILL REMAIN WELL ABOVE CRITICAL LEVELS DURING THE NEXT  
FEW DAYS, SO NO RED FLAG WARNINGS ARE PLANNED AT THIS  
TIME, HOWEVER LARGE WIND DRIVEN FIRES WILL BE POSSIBLE IN MODERATE  
HUMIDITY REGIMES DUE TO THE VERY DRY FUELS.  
 
OTHER TARGET AREAS OF STRONGER WINDS AND ELEVATED FIRE DANGER ON  
SUNDAY AND MONDAY WILL BE THE ANTELOPE VALLEY AND INTERSTATE 5  
CORRIDOR, WHERE GUSTS BETWEEN 35 AND 50 MPH WILL BE COMMON. SUNDAY  
NIGHT THROUGH MONDAY NIGHT, LOCALLY GUSTY NORTHERLY WINDS ARE  
ALSO EXPECTED TO IMPACT THE SANTA CLARITA AND SAN FERNANDO  
VALLEYS, SANTA MONICA MOUNTAINS, AND HOLLYWOOD HILLS. THESE GUSTY  
NORTHERLY WINDS WITH LOWERING HUMIDITIES ON MONDAY WILL ALSO BRING  
ELEVATED FIRE DANGER TO THESE AREAS AS WELL.  
 

 
   
LOX WATCHES/WARNINGS/ADVISORIES
 
 
CA...NONE.  
PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT SUNDAY FOR ZONE  
645. (SEE LAXMWWLOX).  
SMALL CRAFT ADVISORY IN EFFECT UNTIL 6 PM PDT SUNDAY FOR  
ZONES 670-673-676. (SEE LAXMWWLOX).  
GALE WATCH IN EFFECT FROM SUNDAY EVENING THROUGH MONDAY  
EVENING FOR ZONES 673-676. (SEE LAXMWWLOX).  
 

 
 

 
 
PUBLIC...JLD  
FIRE...GOMBERG  
AVIATION...30  
MARINE...30  
SYNOPSIS...SWEET  
 
WEATHER.GOV/LOSANGELES  
 
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