917  
FXUS66 KLOX 250654  
AFDLOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA  
1154 PM PDT SUN JUN 24 2018  
 
NEW AVIATION  
   
SYNOPSIS
 
24/256 PM.  
 
AFTERNOON TEMPERATURES WILL WARM SLIGHTLY THROUGH MID WEEK THEN  
COOL SLIGHTLY INTO THE WEEKEND. OVERNIGHT AND MORNING LOW CLOUDS  
WILL CONTINUE THROUGH THE WEEK.  
 

 
   
SHORT TERM (SUN-WED)
 
24/858 PM.  
 
RIDGING ALOFT IS FIRMLY IN PLACE ACROSS THE AREA JUDGING BY THE  
LATEST SATELLITE IMAGERY. THE LATEST AMDAR SOUNDINGS FROM KLAX  
INDICATE THE MARINE LAYER DEPTH HAS THINNED BY 500 FEET AT KLAX  
AND ONSHORE PRESSURE GRADIENTS ARE WEAKENING AS PREVIOUSLY  
SURMISED. SUBSIDING AIR ALOFT WITH THE HIGH PRESSURE SYSTEM WILL  
PRESS DOWN ON TOP OF THE MARINE LAYER AND CONTINUE TO WEAKEN  
ONSHORE PRESSURE GRADIENTS INTO MONDAY. A WARMING TREND WILL  
DEVELOP THROUGH MONDAY, WARMEST ACROSS THE VALLEYS AND INTERIOR  
SECTIONS. THE EXCEPTION COULD BE FOR MOST OF THE CENTRAL COAST AS  
THE SOUTHEAST LOW-LEVEL FLOW THAT HAS CREATED DOWNSLOPE WARMING  
WILL SUBSIDE AND ALLOW FOR COOLER MARINE AIR TO PUSH INTO THE  
CENTRAL COAST MONDAY.  
 
NO UPDATES ARE PLANNED AT THIS TIME.  
 
*** FROM PREVIOUS DISCUSSION ***  
 
SLIGHT WARMING TREND TO CONTINUE INTO TUESDAY BEFORE LEVELING OFF  
OR COOLING SLIGHTLY WED WITH INCREASING WEST/EAST GRADIENTS.  
BETTER CHANCE OF A MORE COMPLETE COASTAL CLEARING THOSE DAYS AS A  
LITTLE NORTH FLOW SETS UP IN THE AFTERNOONS, ESPECIALLY WEDNESDAY.  
   
LONG TERM (THU-SUN)
 
24/135 PM.  
 
THE RIDGE ALOFT WILL SHIFT EAST THURSDAY AS A TROUGH PUSHES  
ONSHORE ALONG THE WEST COAST. THIS WILL BRING COOLING TO MOST  
AREAS. FRIDAY WILL BE A MIXED BAG OF TEMPERATURE TRENDS WITH  
SLO/SB COUNTIES WARMING WHILE LA/VENTURA COUNTIES COOL SLIGHTLY  
WITH THE TROUGH AXIS JUST PASSING THROUGH THERE BY EVENING.  
POSSIBLY SOME LOW GRADE SUNDOWNER WINDS THURSDAY AND FRIDAY  
NIGHTS. NOT AS MUCH CONFIDENCE IN THE WEEKEND FORECAST AS THE  
ECMWF IS FASTER BUILDING THE RIDGE IN FROM THE WEST AND WARMER.  
PROBABLY NOT A HUGE DIFFERENCE EITHER WAY THOUGH AND OF MINIMAL  
IMPACT.  
 

 
   
AVIATION
 
25/0653Z.  
 
AT 22Z, THE MARINE LAYER DEPTH WAS AROUND 1700 FEET DEEP AT KLAX.  
THE TOP OF THE INVERSION WAS AROUND 4000 FEET WITH A TEMPERATURE  
AROUND 22 DEGREES CELSIUS.  
 
HIGH CONFIDENCE IN 06Z TAFS FOR KPMD AND KWJF WITH MODERATE  
CONFIDENCE ELSEWHERE DUE TO UNCERTAINTY IN TIMING AND FLIGHT  
CATEGORY OF LOW CIGS/VSBYS. FLIGHT CATEGORY MAY BE ONE LOWER AT  
TIMES THROUGH 20Z. TIMING OF FLIGHT CATEGORY CHANGES SHOULD BE  
GENERALLY WITHIN TWO HOURS. THERE IS A 20 PERCENT CHANCE THAT VFR  
CONDS PREVAIL AT KPRB.  
 
KLAX...MODERATE CONFIDENCE IN 06Z TAF. THERE IS A 20 PERCENT  
CHANCE OF IFR CIGS/VSBYS THROUGH 14Z. VFR CIGS/VSBYS EXPECTED TO  
RETURN BETWEEN 16Z AND 19Z.  
 
KBUR...MODERATE CONFIDENCE IN 06Z TAF. THERE IS A 40 PERCENT  
CHANCE OF IFR CIGS/VSBYS THROUGH 14Z. VFR CIGS/VSBYS EXPECTED TO  
RETURN BETWEEN 16Z AND 18Z.  
 

 
   
MARINE
 
24/753 PM.  
 
FOR THE OUTER WATERS...CONDITIONS WILL REMAIN BELOW SCA LEVEL  
THROUGH MONDAY NIGHT. THERE IS A 40% CHANCE OF SCA CONDITIONS  
DEVELOPING TUESDAY AFTERNOON AND NIGHT, AND A 60% CHANCE BY  
WEDNESDAY NIGHT THROUGH FRIDAY, WITH A 30% CHANCE OF GALE FORCE  
GUSTS THURSDAY INTO FRIDAY.  
 
FOR THE INNER WATERS NORTH OF POINT SAL... CONDITIONS WILL REMAIN  
BELOW SCA LEVELS THROUGH WEDNESDAY THEN A 40% CHANCE OF SCA  
CONDITIONS THURSDAY INTO FRIDAY.  
 
FOR THE INNER WATERS SOUTH OF POINT CONCEPTION...THERE WILL BE A  
40% CHANCE OF SCA CONDITIONS THURSDAY AND FRIDAY ACROSS THE  
WESTERN SANTA BARBARA CHANNEL, OTHERWISE CONDITIONS WILL REMAIN  
BELOW SCA CRITERIA.  
 

 
   
LOX WATCHES/WARNINGS/ADVISORIES
 
 
CA...NONE.  
PZ...NONE.  
 

 
 
.HAZARD POTENTIAL OUTLOOK (WED-SUN).  
 
NO SIGNIFICANT HAZARDS EXPECTED.  
 

 
 

 
 
PUBLIC...HALL/MW  
AVIATION...MUNROE  
MARINE...SMITH  
SYNOPSIS...KJ  
 
WEATHER.GOV/LOSANGELES  
 
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