823  
FXUS66 KLOX 241631  
AFDLOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA  
931 AM PDT SUN JUL 24 2016  
   
SYNOPSIS
 
 
HIGH PRESSURE ACROSS THE SOUTHWEST US AND ONSHORE FLOW WILL  
SUPPORT NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES THROUGH MOST OF  
THE NEXT SEVEN DAYS WITH A RETURN OF NIGHT TO MORNING LOW CLOUDS  
TO COASTAL AND VALLEY AREAS. AN INFLUX OF MONSOONAL MOISTURE MAY  
BRING THUNDERSTORMS ACROSS INTERIOR AREAS LATE NEXT WEEK.  
 

 
   
SHORT TERM
 
(TDY-TUE)  
 
NO SIGNIFICANT CHANGES MADE TO THE FORECAST THIS MORNING. JUST  
ABOUT EVERYWHERE WILL BE MUCH COOLER THAN YESTERDAY, WITH 5-15  
DEGREES OF COOLING EXPECTED IN MOST PLACES. HOWEVER, EVEN WITH THE  
COOLING, MOST AREAS WILL REMAIN SLIGHTLY ABOVE NORMAL. THE  
COOLING WILL MOSTLY BE THE RESULT OF AN INCREASE IN ONSHORE FLOW,  
WITH ONLY SMALL DECREASES IN HEIGHT/THICKNESS VALUES. LOW CLOUDS  
AND PATCHY DENSE FOG NEAR THE IMMEDIATE COAST THIS MORNING SHOULD  
CLEAR OUT BY THIS AFTERNOON, BUT WOULDN'T BE SURPRISED IF IT HUGS  
THE COAST IN A FEW PLACES FOR MUCH OF THE DAY. THE MAIN WEATHER  
CONCERN FOR TODAY WILL CONTINUE TO BE THE EXTREME FIRE DANGER IN  
THE LA COUNTY MOUNTAINS, WHERE A RED FLAG WARNING REMAINS IN PLACE  
THROUGH 10PM THIS EVENING FOR VERY LOW RH VALUES AND GUSTY SOUTH  
TO SOUTHWEST WINDS. THERE SHOULD BE MUCH LESS IN THE WAY OF SMOKE  
ACROSS LA COUNTY AND EASTERN VENTURA COUNTY TODAY, AS SOUTH TO  
SOUTHWEST WINDS ALOFT SHOULD TRANSPORT SMOKE FROM THE SAND FIRE  
NORTHWARD.  
 
***FROM PREVIOUS DISCUSSION***  
 
THERE WILL BE VERY LITTLE CHANGE TO THE WEATHER ON MONDAY. HGTS  
ARE ABOUT THE SAME AS WILL BE THE SFC GRADS. THE EDDY IS FORECAST  
TO SPIN UP AGAIN SO ALMOST ALL OF THE BEACHES AND NEAR BEACH AREAS  
WILL HAVE SOME MORNING CLOUDS.  
 
ALL OF THE SHORT RANGE MDLS SHOW SIMILAR DAYS TUE AND WED. THE BIG  
CHANGE WILL BE WITH THE DAILY STRATUS ROUTINE. IT LOOKS LIKE THE  
EDDY WILL PULL A LITTLE MORE TO THE SOUTHWEST WHICH WILL DRAG THE  
CLOUDS AWAY FROM THE VTA AND SBA COASTS. THERE WILL STILL BE SOME  
CLOUDS OVER THE LA COAST AS WELL AS THE CENTRAL COAST.  
SYNOPTICALLY AN UPPER HIGH FORMS OVER NEVADA ON TUESDAY AND THEN  
MOVES OVER THE CA/NV STATE LINE ON WEDNESDAY. THERE WILL REALLY BE  
LITTLE DAY TO DAY CHANGE IN TEMPS ACROSS THE COASTS AND VLYS...BUT  
THE MTNS AND INTERIOR SECTIONS WILL SEE SOME WARMING EACH DAY ESP  
WEDNESDAY.  
 
THE HIGHS WESTERLY POSITION WILL ELIMINATE ANY CHANCE OF A  
MONSOON FLOW PATTERN.  
   
LONG TERM
 
(WED-SAT)  
 
BOTH THE EC AND THE GFS AGREE THAT THE UPPER HIGH WILL REMAIN  
NEARLY STATIONARY OVER THE NV/CA BORDER ON THURSDAY. THE HIGH HGTS  
WILL KEEP THE MARINE LAYER STRATUS SMOOSHED DOWN ON THE BEACHES.  
WARMER THAN NORMAL TEMPS WILL CONTINUE AS WELL BUT THE COASTS AND  
VLYS WILL BE TEMPERED SOME BY THE SEA BREEZE. THE INTERIOR NOT SO  
MUCH AND THURSDAY WILL BE VERY HOT WITH TRIPLE DIGIT HEAR THE  
NORM. THE ANTELOPE VLY WILL HAVE HIGHS MOSTLY BETWEEN 105 AND 110  
DEGREES. STILL NO MONSOON FLOW.  
 
MDLS DISAGREE ON THE FRI/SAT DAY 6/7 FORECAST. THE EC MOVES THE UPPER  
HIGH WESTWARD RIGHT OVER THE STATE WHICH WOULD RESULT IN VERY  
LITTLE DAY TO DAY CHANGE IN THE WEATHER. THE GFS MOVES THE UPPER  
HIGH TO THE WEST. THIS SOLUTION WOULD RESULT IN SOME COOLING BUT  
MORE IMPORTANTLY WOULD OPEN THE DOOR TO THE MONSOON FLOW. FOLLOWED  
THE GFS FOR THE EXTENDED FORECAST AS ITS ENSEMBLES LOOK A LITTLE  
TIGHTER THAN THE EC'S. SO THERE IS A 20 PERCENT CHC OF AFTERNOON  
AND EARLY EVENING CONVECTION OVER THE LA/VTA MTNS AS WELL AS THE  
ANTELOPE VLY.  
 

 
   
AVIATION...24/12Z
 
 
AT 08Z AT KLAX, THE INVERSION WAS SURFACE BASED. THE TOP OF THE  
INVERSION WAS NEAR 2800 FEET WITH A TEMPERATURE OF 29 DEGREES  
CELSIUS.  
 
OVERALL... LOW TO MODERATE CONFIDENCE IN THE 12Z TAFS. THE  
REDUCED CONFIDENCE IS PRIMARILY DUE TO THE UNCERTAINTY IN THE  
TIMING... LOCATION... AND INTENSITY OF THE MARINE INTRUSION. A  
WEAK MARINE INTRUSION HAS BEEN DEVELOPING OVERNIGHT IN THE  
COASTAL AREAS SOUTH OF POINT CONCEPTION. STRATUS THAT DEVELOPS IN  
THIS AREA WOULD LIKELY RESULT IN LIFR/IFR CONDITIONS. PATCHY DENSE  
FOG HAS BEEN DEVELOPING ALONG THE COAST NORTH OF POINT  
CONCEPTION... AFFECTING KSMX BUT NOT KSBP. FOG THAT DEVELOPS IN  
THIS AREA WOULD LIKELY RESULT IN IFR/MVFR CONDITIONS. LOW CLOUDS  
AND FOG WILL DIMINISH BY 18Z. SMOKE WILL BE IN THE 120-150 HEIGHT  
RANGE THROUGH MUCH OF LOS ANGELES AND VENTURA COUNTIES. OTHERWISE  
AND ELSEWHERE VFR CONDITIONS WILL PREVAIL.  
 
KLAX... MODERATE CONFIDENCE IN THE 12Z TAF. THE REDUCED  
CONFIDENCE IS PRIMARILY DUE TO THE UNCERTAINTY IN THE TIMING AND  
INTENSITY OF THE MARINE INTRUSION. A WEAK MARINE INTRUSION HAS  
BEEN DEVELOPING OVERNIGHT AND SHOULD RESULT IN A SHORT PERIOD OF LIFR/IFR  
CONDITIONS. LOW CIGS WILL DIMINISH BY 17Z. SMOKE WILL BE IN THE  
120-150 HEIGHT RANGE THROUGH MUCH OF THE FORECAST PERIOD.  
OTHERWISE VFR CONDITIONS WILL PREVAIL.  
 
KBUR... MODERATE TO HIGH CONFIDENCE IN THE 12Z TAF. THE REDUCED  
CONFIDENCE IS PRIMARILY DUE TO THE UNCERTAINTY IN THE TIMING AND  
INTENSITY OF THE MARINE INTRUSION. THERE IS A TEN PERCENT CHANCE  
OF LOW CIGS THROUGH 15Z. SMOKE WILL BE IN THE 120-150 HEIGHT  
RANGE THROUGH MUCH OF THE FORECAST PERIOD. OTHERWISE VFR  
CONDITIONS WILL PREVAIL.  
 

 
   
MARINE...24/920 AM
 
 
NOT EXPECTING ANY SMALL CRAFT ADVISORIES THROUGH AT LEAST  
WEDNESDAY. THERE WILL BE SOME GUSTY NW WINDS ACROSS THE NW PORTION  
OF THE ZONE PZ670 THROUGH THIS AFTERNOON. A STRONG EDDY WILL  
DEVELOP OVERNIGHT INTO MONDAY MORNING ACROSS SOCAL BIGHT.  
SUSTAINED WINDS AS HIGH AS 12 KT WILL BE POSSIBLE. ESPECIALLY  
ACROSS THE SAN PEDRO CHANNEL BOTH EARLY SUNDAY AND MONDAY MORNING.  
 
THERE WILL PATCHY DENSE FOG WITH VISIBILITY 1 NM OR LESS THROUGH  
MID AFTERNOON OFF THE CENTRAL COAST. THE EDDY SHOULD ALLOW FOR  
BETTER VISIBILITY ACROSS THE INNER WATERS OF LOS ANGELES, VENTURA  
AND SANTA BARBARA COUNTIES THROUGH THIS AFTERNOON.  
 

 
   
LOX WATCHES/WARNINGS/ADVISORIES
 
 
CA...RED FLAG WARNING IN EFFECT UNTIL 10 PM PDT THIS EVENING FOR  
ZONE 254. (SEE LAXRFWLOX).  
PZ...NONE.  
 

 
 

 
 
PUBLIC...SUKUP  
AVIATION...KJ  
MARINE...KAPLAN  
SYNOPSIS...MUNROE  
 
WEATHER.GOV/LOSANGELES  
 
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