840  
FXUS66 KLOX 270409  
AFDLOX  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA  
909 PM PDT WED JUL 26 2017  
   
SYNOPSIS
 
 
NIGHT AND MORNING LOW CLOUDS AND FOG WILL AFFECT COASTAL AREAS  
THROUGH EARLY NEXT WEEK. OTHERWISE, UPPER LEVEL HIGH PRESSURE  
WILL KEEP MOSTLY CLEAR SKIES AND SEASONABLY WARM TEMPERATURES OVER  
SOUTHWESTERN CALIFORNIA THROUGH SATURDAY, THEN MONSOONAL MOISTURE  
WILL MOVE IN FOR PARTLY CLOUDY SKIES SUNDAY THROUGH EARLY NEXT  
WEEK. THERE WILL ALSO BE A SLIGHT CHANCE OF MOUNTAIN AND DESERT  
THUNDERSTORMS EACH DAY SUNDAY THROUGH WEDNESDAY.  
 

 
   
SHORT TERM
 
(WED-SAT)  
 
THE LATEST VISIBLE IMAGERY SHOWS CLOUD BUILD UPS OVER THE  
MOUNTAINS AND DESERT THIS AFTERNOON AS SOME MONSOONAL MOISTURE  
CLINGS ONTO THE AREA. PRIMARILY PARTLY CLOUDY SKIES WILL DEVELOP  
THIS AFTERNOON AND EVENING. AN ISOLATED SHOWER CANNOT BE RULED  
OUT LATER TODAY, BUT ANY SHOWER THAT DEVELOP WOULD LIKELY BE  
SHORT-LIVED AND RAIN AMOUNT WOULD NOT AMOUNT TO MUCH.  
 
OTHERWISE, HIGH PRESSURE ALOFT CENTERED OVER EASTERN NEW MEXICO  
THIS AFTERNOON WILL GRADUALLY BUILD WEST INTO THE FOUR CORNERS  
REGION THROUGH FRIDAY. 500 MB HEIGHTS CLIMB AND 1000-500 MB  
THICKNESS VALUES INCREASE THROUGH LATE WEEK. A WARMING TREND WILL  
OCCUR THROUGH AT LEAST THURSDAY, AND POSSIBLY INTO FRIDAY. THE  
LATEST 18Z NAM-WRF MODEL SOLUTIONS ARE STARTING TO BACK OFF ON  
FRIDAY BEING THE WARMEST DAY AS AN EDDY CIRCULATION DEVELOPS OVER  
THE COASTAL WATERS, WHICH SHOULD STRENGTHEN ONSHORE PRESSURE  
GRADIENTS. REGARDLESS, TEMPERATURES WILL LIKELY REMAIN ON THE HIGH  
SIDE OF NORMAL FOR FRIDAY. LESS STRATUS COVERAGE WILL LIKELY  
DEVELOP OVER THE NEXT SEVERAL DAYS. THE BEST CONFIDENCE IN STRATUS  
COVERAGE IS FOR THE CENTRAL COAST PORTION, WHILE LESS CONFIDENCE  
EXISTS FOR THE SOUTH COAST PORTION.  
   
LONG TERM
 
(SUN-WED)  
 
THE FORECAST GETS A BIT MORE UNCLEAR FOR EARLY NEXT WEEK. GFS AND  
ECMWF MODEL SOLUTIONS DIVERGE IN THE TIMING OF THE REMNANTS  
HURRICANE HILARY AND MAYBE THE COMBO OF THE REMNANTS OF HURRICANE  
HILARY AND IRWIN FOR EARLY NEXT WEEK. GFS SOLUTIONS ARE MORE  
AGGRESSIVE RELATIVE TO THE ECMWF MODEL SOLUTIONS IN BRINGING  
REMNANTS INTO SOUTHERN CALIFORNIA. UNFORTUNATELY, GFS ENSEMBLE  
MEMBERS OFFER LITTLE HELP IN THE FINER DETAILS AND PERTURBATIONS  
OF THE MODEL DIVERGE AS WELL. HIGH CONFIDENCE EXISTS IN A WARM AIR  
MASS REMAINING, POSSIBLY HUMID AT TIMES. LESS CONFIDENCE EXISTS  
IN THE TIMING OF THE RAIN CHANCES NEXT WEEK, A BLANKET OF SLIGHT  
CHANCE POPS IS IN THE FORECAST FOR NOW UNTIL BETTER CONFIDENCE  
EXISTS.  
 

 
   
AVIATION
 
27/0030Z.  
 
AT 00Z, THE MARINE LAYER DEPTH WAS AROUND 1250 FEET. THE TOP OF  
THE MARINE INVERSION WAS AROUND 2000 FEET WITH A TEMPERATURE NEAR  
22 DEGREES CELSIUS. THERE WAS ANOTHER INVERSION ABOVE UP TO AROUND  
4000 FEET.  
 
LIFR TO IFR CONDITIONS WILL LIKELY SPREAD INTO COASTAL TERMINALS  
THROUGH 13Z, THEN CONTINUE THROUGH AT LEAST 16Z. VFR CONDITIONS  
SHOULD REDEVELOP BETWEEN 16Z AND 18Z. THERE IS A CHANCE OF VLIFR  
CONDITIONS AT TERMINALS NORTH OF KSBA BETWEEN 08Z AND 14Z.  
 
KLAX...THERE IS A 70 PERCENT CHANCE OF IFR CONDITIONS DEVELOPING  
BETWEEN 07Z AND 13Z, THEN CONTINUING THROUGH AT LEAST 16Z OR 17Z.  
 
KBUR...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD. THERE IS  
A 20 PERCENT CHANCE OF MVFR VISIBILITIES BETWEEN 10Z AND 16Z.  
 

 
   
MARINE
 
26/800 PM.  
 
FOR THE OUTER WATERS, MODERATE CONFIDENCE IN CURRENT FORECAST.  
GUSTY WINDS AROUND POINT CONCEPTION INDICATED TO BECOME MORE  
WIDESPREAD AND PERSIST THROUGH LATE TONIGHT SO A SCA HAS BEEN  
ISSUED TO PZZ673. OTHERWISE, WINDS AND SEAS EXPECTED TO REMAIN  
BELOW SMALL CRAFT ADVISORY (SCA) LEVELS THROUGH THURSDAY. THURSDAY  
NIGHT THROUGH SATURDAY THERE IS A CHANCE OF SCA LEVEL WINDS  
ACROSS PZZ670/673. WINDS SHOULD DECREASE BELOW SCA LEVELS ACROSS  
ALL THE OUTER WATERS ON SUNDAY.  
 
FOR THE INNER WATERS, GOOD CONFIDENCE IN CURRENT FORECAST. FOR ALL  
THE WATERS, WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA LEVELS  
THROUGH SUNDAY. CHOPPY SEAS BELOW SCA LEVELS WILL PERSIST THROUGH  
LATE TONIGHT.  
 

 
   
LOX WATCHES/WARNINGS/ADVISORIES
 
 
CA...BEACH HAZARDS STATEMENT IN EFFECT FROM FRIDAY MORNING THROUGH  
TUESDAY EVENING FOR ZONES 40-41-87. (SEE LAXCFWLOX).  
PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT THURSDAY FOR  
ZONE 673. (SEE LAXMWWLOX).  
 

 
   
HAZARD POTENTIAL OUTLOOK
 
(SAT-WED)  
 
A HIGH SURF EVENT SHOULD PEAK OVER THE WEEKEND AS A LONG-PERIOD  
SOUTHERLY SWELL ARRIVES AT THE SOUTHERN CALIFORNIA BEACHES. HIGH  
SURF AND STRONG RIP CURRENTS WILL OCCUR THROUGH THE WEEKEND AND  
PROBABLY INTO LATE NEXT WEEK.  
 

 
 

 
 
PUBLIC...HALL  
AVIATION...HALL  
MARINE...SMITH  
BEACHES...SMITH  
SYNOPSIS...SIRARD  
 
WEATHER.GOV/LOSANGELES  
 
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