287  
FXUS66 KLOX 231152  
AFDLOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA  
452 AM PDT SAT SEP 23 2017  
   
..AVIATION DISCUSSION UPDATED
 
 
   
SYNOPSIS
 
 
GRADUALLY STRENGTHENING OFFSHORE FLOW WILL BRING A WARMING AND  
DRYING TREND TO THE AREA THROUGH NEXT WEEK. AT TIMES, THERE WILL  
BE SOME GUSTY NORTH TO NORTHEAST WINDS ACROSS THE AREA. MOSTLY  
CLEAR SKIES ARE EXPECTED AS THE NORTH TO NORTHEAST WINDS LIMIT THE  
DEVELOPMENT OF THE NIGHT AND MORNING LOW CLOUDS AND FOG.  
 

 
   
SHORT TERM
 
(TDY-MON)  
 
OVERALL, 00Z MODELS IN VERY GOOD SYNOPTIC AGREEMENT THROUGH THE  
PERIOD. AT UPPER LEVELS, LOW WILL MEANDER OVER THE GREAT BASIN  
TODAY THROUGH SUNDAY THEN MOVE EASTWARD ON MONDAY. NEAR THE  
SURFACE, OFFSHORE GRADIENTS WILL GRADUALLY INCREASE THROUGH THE  
PERIOD.  
 
FORECAST-WISE, MAIN CONCERNS IN THE SHORT TERM WILL BE OFFSHORE  
WINDS AND TEMPERATURES. WITH RESPECT TO WINDS, THE GRADUAL  
INCREASE IN OFFSHORE GRADIENTS WILL RESULT IN AN INCREASE IN NORTH  
TO NORTHEAST WINDS ACROSS THE AREA. AT THIS TIME, THE UPPER LEVEL  
SUPPORT IS NOT OVERLY IMPRESSIVE, SO DO NOT ANTICIPATE ANY  
WIDESPREAD ADVISORY-LEVEL WINDS THROUGH MONDAY. HOWEVER, THERE  
WILL BE SOME LOCALLY GUSTY OFFSHORE WINDS IN THE USUAL SPOTS  
(ACROSS SOUTHERN SBA COUNTY EARLY THIS MORNING THEN SHIFTING TO  
VENTURA AND LOS ANGELES COUNTIES TODAY AND CONTINUING THROUGH  
MONDAY).  
 
OTHERWISE, THE OVERALL SYNOPTIC PATTERN (INCREASING OFFSHORE  
SURFACE GRADIENTS AND INCREASING THICKNESSES/H5 HEIGHTS) WILL  
RESULT IN A WARMING TREND ACROSS THE AREA THROUGH MONDAY. IN FACT  
BY MONDAY, MOST COASTAL AND VALLEY AREAS WILL BE A FEW DEGREES  
ABOVE SEASONAL NORMALS. ADDITIONALLY, OVERNIGHT LOWS WILL BE  
GRADUALLY INCREASING THROUGH THE PERIOD.  
 
AS FOR CLOUDS, GENERALLY MOSTLY CLEAR SKIES WILL PREVAIL THROUGH  
THE PERIOD. THERE WILL BE SOME PATCHY STRATUS/FOG THIS MORNING  
ALONG THE CENTRAL COAST, BUT OTHERWISE COASTAL AND VALLEY AREAS  
ARE EXPECTED TO REMAIN STRATUS-FREE THROUGH THE PERIOD.  
   
LONG TERM
 
(TUE-FRI)  
 
OVERALL, 00Z MODELS EXHIBIT DECENT SYNOPTIC AGREEMENT THROUGH THE  
PERIOD. AT UPPER LEVELS, LOW DEVELOPS OVER THE EASTERN DESERTS ON  
TUESDAY AND MEANDERS ACROSS THE EASTERN DESERTS AND GREAT BASIN  
THROUGH THE PERIOD. NEAR THE SURFACE, OFFSHORE FLOW WILL CONTINUE  
ALTHOUGH THE FLOW SHOULD WEAKEN BY THE END OF NEXT WEEK.  
 
FORECAST-WISE, MAIN CONCERNS WILL CONTINUE TO BE OFFSHORE WINDS  
AND TEMPERATURES. NORTHEASTERLY WINDS WILL CONTINUE THROUGH THE  
PERIOD WITH THE STRONGEST WINDS LIKELY TUESDAY/WEDNESDAY.  
DEPENDING ON EXACTLY WHERE THE UPPER LOW MEANDERS, THE UPPER LEVEL  
SUPPORT COULD INCREASE OR DECREASE. AT THIS TIME, STILL DO NOT  
ANTICIPATE ANY WIDESPREAD ADVISORY-LEVEL WINDS ACROSS THE AREA,  
BUT THIS POSSIBILITY WILL NEED TO BE CLOSELY MONITORED THE NEXT  
FEW DAYS. AS THE OFFSHORE WINDS CONTINUES, SKIES SHOULD REMAIN  
MOSTLY CLEAR FOR ALL AREAS AS STRATUS DEVELOPMENT SHOULD BE NIL.  
 
WITH THE CONTINUED OFFSHORE FLOW, TEMPERATURES WILL REMAIN WELL  
ABOVE SEASONAL NORMALS THROUGH THE PERIOD WITH NEXT FRIDAY  
POTENTIALLY THE WARMEST DAY. OVERNIGHT LOWS WILL ALSO REMAIN WARM  
THROUGH THE PERIOD.  
 

 
   
AVIATION
 
23/12Z.  
 
AT 11Z AT KLAX... THERE WAS NO NOTABLE INVERSION.  
 
OVERALL... MODERATE TO HIGH CONFIDENCE IN THE CURRENT TAFS. THERE  
IS A THIRTY PERCENT CHANCE OF LIFR/IFR CONDITIONS THROUGH 20Z AT  
CENTRAL COAST TERMINALS AND A TWENTY PERCENT CHANCE OF MVFR  
CONDITIONS THROUGH 20Z AT COASTAL LOS ANGELES COUNTY TERMINALS.  
THERE IS A LESS THAN TEN PERCENT CHANCE OF MVFR CONDITIONS THROUGH  
18Z AT KBUR AND KVNY. OTHERWISE AND ELSEWHERE VFR CONDITIONS WILL  
PREVAIL.  
 
KLAX... MODERATE TO HIGH CONFIDENCE IN THE CURRENT TAF. THERE  
IS A TWENTY PERCENT CHANCE OF MVFR CONDITIONS THROUGH 20Z.  
OTHERWISE VFR CONDITIONS WILL PREVAIL. THERE IS A FIFTEEN PERCENT  
CHANCE OF EAST WINDS UP TO TEN KNOTS THROUGH 16Z.  
 
KBUR... HIGH CONFIDENCE IN THE CURRENT TAF. THERE IS A LESS THAN  
TEN PERCENT CHANCE OF MVFR CONDITIONS THROUGH 18Z. OTHERWISE VFR  
CONDITIONS WILL PREVAIL.  
 

 
   
MARINE
 
23/200 AM.  
 
SMALL CRAFT ADVISORY (SCA) LEVEL WINDS WILL PERSIST ACROSS THE  
OUTER WATERS THROUGH TONIGHT THEN DIMINISH TO BELOW SCA LEVELS  
SUNDAY THROUGH WEDNESDAY. PORTIONS OF THE INNER WATERS...  
PARTICULARLY IN THE SANTA BARBARA CHANNEL... WILL HAVE LOCALLY  
GUSTY WINDS REACH SCA LEVELS TODAY. OTHERWISE CONDITIONS ACROSS  
THE INNER WATERS WILL REMAIN BELOW ADVISORY LEVELS THROUGH  
WEDNESDAY.  
 
SHORT PERIOD CHOPPY SEA CONDITIONS WILL PERSIST ACROSS THE COASTAL  
WATERS TODAY.  
 

 
   
LOX WATCHES/WARNINGS/ADVISORIES
 
 
CA...NONE.  
PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT SUNDAY FOR  
ZONES 670-673-676. (SEE LAXMWWLOX).  
 

 
   
HAZARD POTENTIAL OUTLOOK
 
(MON-FRI)  
IT WILL BE HOT THROUGH NEXT WEEK, ESPECIALLY AWAY FROM THE COAST.  
THERE WILL BE GUSTY NORTHEAST WINDS AT TIMES, ESPECIALLY ACROSS  
LOS ANGELES AND VENTURA COUNTIES TUESDAY AND WEDNESDAY. THE  
COMBINATION OF HEAT, GUSTY WINDS AND LOW RELATIVE HUMIDITY VALUES  
WILL BRING HEIGHTENED FIRE DANGER, ESPECIALLY TO THE MOUNTAINS AND  
VALLEYS THROUGH THE WEEK.  
 

 

 
 
PUBLIC...THOMPSON  
AVIATION...KJ  
MARINE...KJ  
SYNOPSIS...THOMPSON  
 
WEATHER.GOV/LOSANGELES  
 
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