651  
FXUS66 KLOX 251201  
AFDLOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA  
501 AM PDT WED MAY 25 2016  
   
SYNOPSIS
 
 
LOW PRESSURE WILL MOVE ACROSS THE AREA TODAY AND WILL RESULT IN  
COOL WEATHER AND A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS,  
MAINLY FOR THE MOUNTAINS AND SOME INTERIOR AREAS. WARMING IS  
EXPECTED LATE THIS WEEK AS THE MAIN UPPER LOW MOVES EAST, BUT  
TEMPERATURES WILL REMAIN NEAR OR SLIGHTLY BELOW NORMAL THROUGH  
EARLY NEXT WEEK AS A WEAK TROUGH LINGERS OVER THE AREA.  
 

 
   
SHORT TERM
 
(TDY-FRI)  
 
ACARS SOUNDINGS OUT OF KLAX SHOW A 6000 FOOT DEEP MOIST LAYER WITH  
LITTLE OR NO INVERSION ON TOP. GRADIENTS ARE COMFORTABLY ONSHORE  
AND MOST IMPORTANTLY AN UPPER LOW SITS OVER PT. CONCEPTION. A  
DECENT MARINE LAYER STRATUS DECK HAS MANAGED TO FORM MOSTLY DUE TO  
THE LIFT FORM THE UPPER LOW...BUT THERE ARE STILL PLENTY OF BREAKS  
IN THE CLOUDS. REALLY SCALED BACK ON THE RAIN CHCS THIS MORNING  
AND THEY ARE NOW CONFINED TO THE VLYS AND MTNS SOUTH OF PT  
CONCEPTION AND EVEN HERE ITS PROBABLY BEST TO THINK OF THE 20  
PERCENT CHC OF SHOWERS AS AN 80 PERCENT CHC OF NO SHOWERS. THE  
DEEP MOIST LAYER WILL LIKELY RESULT IN ANOTHER DAY WITH REVERSE  
CLEARING SO THE COASTS WILL SEE MORE SUNSHINE THAN THE VLYS. THE  
UPPER LOW IS MOVING A LITTLE QUICKER TO THE EAST AND SOUTH THAN  
WAS FCST YDY AND THIS WILL SHIFT THE AFTERNOON CONVECTIVE FOCUS TO  
THE L.A. MTNS...BUT PVA EMBEDDED IN THE WRAP AROUND FLOW WILL  
ALLOW FOR A SLIGHT CHC OF TSTMS OVER THE REST OF THE MTNS AS WELL  
AS THE INTERIOR SLO VLYS AND THE CUYAMA VLY. THERE IS NOT MUCH  
MOISTURE TO WORK WITH AND THE FLASH FLOOD POTENTIAL IS RATHER LOW. H5  
HGTS WILL BE NEAR 560DM AND MAX TEMPS WILL AGAIN BE BLO NORMAL.  
 
THE UPPER LOW EXITS THE AREA QUICKLY LATER IN THE AFTERNOON AND  
SHOULD TAKE THE CONVECTIVE THREAT ALONG WITH IT LEAVING THE  
EVENING RAIN FREE. CLOUDS WILL DIMINISH OVERNIGHT EXCEPT FOR THE  
CENTRAL COAST WHERE THE MARINE INVERSION WILL REFORM AND LEAD TO A  
WELL DEVELOPED STRATUS LAYER.  
 
PARTLY CLOUDY AT WORST ON THURSDAY. HGTS RISE THROUGH THE DAY AND  
MAX TEMPS WILL BUMP UP A FEW DEGREES BUT MAX TEMPS WILL STILL  
REMAIN BLO NORMALS.  
 
RIDGING MOVES INTO THE AREA THURSDAY NIGHT AND THIS WILL  
REESTABLISH THE MARINE INVERSION. SMALL CRAFT ADVISORY WINDS  
ACROSS THE OUTER WATERS WILL SPIN UP AN EDDY AND LOW CLOUDS WILL  
COVER MOST OF THE COASTS AND VLYS BY SUNRISE.  
 
NEITHER THE EDDY OR THE ONSHORE FLOW WILL BE STRONG ENOUGH TO KEEP  
THE LOW CLOUDS IN AND SKIES WILL BE MOSTLY CLEAR BY THE AFTERNOON.  
THE MARINE LAYER WILL KEEP THE COASTS COOL AND THE VLY TO A LESS  
DEGREE...INLAND TEMPS HOWEVER WILL JUMP NICELY.  
   
LONG TERM
 
(SAT-TUE)  
 
EXTENDED MODELS SHOWING WEAK UPPER LEVEL TROUGH ACROSS CALIFORNIA  
OVER THE WEEKEND, WITH CONTINUED STRONG ONSHORE FLOW NEAR THE  
SURFACE. THIS WILL MAINTAIN MILD TEMPERATURES, ALONG WITH NIGHT  
AND MORNING MARINE LAYER CLOUDS, AND GUSTY ONSHORE WINDS IN THE  
MOUNTAINS AND DESERTS. SOME WEAK UPPER LEVEL RIDGING EXPECTED TO  
FOLLOW MONDAY INTO TUESDAY, LEADING TO A FEW DEGREES OF WARMING  
ACROSS INTERIOR AREAS.  
 

 
   
AVIATION
 
 
25/1200Z  
 
AT 1145Z AT KLAX...THERE WAS A 6500 FOOT DEEP MARINE LAYER. THERE  
WAS A WEAK INVERSION ABOVE THE MARINE LAYER OR MOIST LAYER WITH A  
TOP OF 7500 FEET AND A TEMPERATURE OF 3 DEGREES CELSIUS,  
 
THERE WILL CONTINUE TO BE LOW CONFIDENCE WITH THE 12Z TAFS. THE  
COMBINATION OF A DEEP MOIST LAYER, WEAK INVERSION AND AN UPPER LOW  
MOVING OVERHEAD TODAY, MAKES IT DIFFICULT TO PIN POINT HOW MANY  
CLOUD LAYERS THERE WILL BE. THERE WILL BE HIGHER CONFIDENCE THAT  
THERE WILL NOT BE LOWER THAN MVFR CIGS OVER THE NEXT 24 HOURS.  
THERE IS A 30 PERCENT CHANCE THAT COASTAL CIGS COULD CLEAR OUT  
LATER TODAY. SOME LLWS AND UDDF WILL BE POSSIBLE AROUND KSBA FROM  
21Z-8Z THIS EVENING INTO THU MORNING.  
 
KLAX...LOW CONFIDENCE IN 12Z TAF. THERE IS A GOOD CHANCE THERE  
WILL BE AN EQUAL POSSIBILITY THROUGH THE NEXT 24 HOURS THAT THERE  
WILL BE NO CIGS UNDER MVFR BUT IT WILL VARY FROM LOW MVFR TO VFR.  
THERE IS A 20 % CHANCE FOR NO CIGS AFTER 18Z.  
 
KBUR...LOW CONFIDENCE IN 12Z TAF. CIGS OF 015 025 AND 035 ARE EQUALLY  
POSSIBLE OVER THE NEXT 24 HOURS. OR A 30 PERCENT CHANCE THAT NO  
CIGS WILL DEVELOP AFTER 02Z THIS EVENING THROUGH THE OVERNIGHT  
HOURS. THERE IS A 30 PERCENT CHC OF BKN025 AFT 18Z.  
 

 
   
MARINE
 
25/3:45AM  
 
MAINLY LIGHT WINDS AND SMALL SEAS ARE EXPECTED THROUGH WEDNESDAY  
MORNING, WITH NO SCA CONCERNS. SMALL CRAFT ADVISORIES HAVE BEEN  
ISSUED FOR ALL COASTAL WATERS BEGINNING THIS AFTERNOON. THE OUTER  
WATERS SCA WILL CONTINUE THROUGH AT LEAST MID MORNING ON FRIDAY,  
WHILE THE INNER WATERS WILL EXPIRE OVERNIGHT. CONFIDENCE IS 70%  
THAT ANOTHER SCA WILL BE NEEDED FOR THE NORTHERN AND WESTERN  
PORTION OF THE OUTER WATERS FRIDAY AFTERNOON THROUGH THE WEEKEND.  
LESS CONFIDENCE ON SUNDAY.  
 

 
   
LOX WATCHES/WARNINGS/ADVISORIES
 
 
CA...NONE.  
PZ...SMALL CRAFT ADVISORY IN EFFECT FROM 3 PM THIS AFTERNOON TO 3  
AM PDT THURSDAY FOR ZONES 645-650. (SEE LAXMWWLOX).  
SMALL CRAFT ADVISORY IN EFFECT FROM 3 PM THIS AFTERNOON TO 9  
PM PDT THIS EVENING FOR ZONE 655. (SEE LAXMWWLOX).  
SMALL CRAFT ADVISORY IN EFFECT FROM 3 PM THIS AFTERNOON TO 9  
AM PDT FRIDAY FOR ZONES 670-673-676. (SEE LAXMWWLOX).  
 

 
 

 
 
PUBLIC...RORKE  
AVIATION...CK  
MARINE...CK  
SYNOPSIS...MUNROE  
 
WEATHER.GOV/LOSANGELES  
 
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