187
FXUS66 KLOX 140342
AFDLOX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
842 PM PDT SAT SEP 13 2025
SYNOPSIS
13/828 PM.
A WARMING TREND WILL CONTINUE WITH TEMPERATURES INCREASING A
COUPLE DEGREES EACH DAY THROUGH THURSDAY NEXT WEEK. NIGHT THROUGH
MORNING LOW CLOUDS AND FOG WILL COVER MANY COASTS AND COASTAL
VALLEYS THROUGH AT LEAST TUESDAY, AND SOME OF THE FOG COULD BECOME
DENSE. THE HEAT WILL PEAK DURING THE MIDDLE OF NEXT WEEK, AND
WILL BE REPLACED BY A SLOW COOLING TREND AS WELL AS CHANCES FOR
SHOWERS AND THUNDERSTORMS STARTING WEDNESDAY AND LASTING THROUGH
THE FOLLOWING WEEKEND.
SHORT TERM (SAT-TUE)
13/842 PM.
***UPDATE***
HIGH TEMPERATURES TODAY RANGED IN THE 60S TO 70S ACROSS THE
BEACHES, 70S TO 80S ACROSS THE VALLEYS, AND UP TO THE LOW 90S
ACROSS SOME OF THE INTERIOR LOCATIONS SUCH AS THE ANTELOPE VALLEY.
CURRENT SATELLITE IMAGERY SHOWS SPLOTCHES OF CLOUDS ACROSS THE
COASTS, AND HONESTLY LOOKS RANDOMLY PLACED. CURRENT FORECAST LEANS
TOWARDS THE CLOUDS FILLING IN MORE, EXPANDING ACROSS THE CENTRAL
COAST, AS WELL AS INTO THE OXNARD PLAINS, ACROSS THE LA COAST AND
POSSIBLE INTO THE COASTAL VALLEYS INCLUDING SAN FERNANDO. HOWEVER,
WITH HOW FAST THE CLOUDS ARE CLEARING OUT FROM THE COASTAL
WATERS, THE CENTRAL COAST MAY STRUGGLE TO SEE WIDESPREAD CLOUDS
OVERNIGHT. SUNDAY WILL CONTINUE TO HAVE BENIGN WEATHER AND HIGH
TEMPERATURES WILL INCREASE ACROSS THE REGION BY 2-5 DEGREES,
LOCALLY UP TO 10 ACROSS THE INTERIOR AND NEAR THE FOOTHILLS.
BESIDES SLIGHT ADJUSTMENT TO THE SKY COVERAGE FOR TONIGHT,
FORECAST LOOKS TO BE IN SHAPE AND NO OTHER CHANGES WERE NEEDED TO
THE EVENING UPDATE.
***FROM PREVIOUS DISCUSSION***
NO SIGNIFICANT WEATHER ISSUES EXPECTED THROUGH TUESDAY. A WEAK
TROUGH WILL MOVE THROUGH OREGON LATER TONIGHT AND SUNDAY BUT THAT
WILL HAVE LITTLE TO NO IMPACT THIS FAR SOUTH. THE MARINE LAYER WAS
STILL AROUND 3000 FEET THIS MORNING SOUTH OF PT CONCEPTION AND IT
SHOULD STILL BE SOMEWHERE BETWEEN 2000 AND 3000 FEET TONIGHT AS
WELL SO EXPECTING MOST COAST AND VALLEY AREAS TO FILL IN WITH
STRATUS OVERNIGHT. SOME LOWERING OF THE MARINE LAYER IS EXPECTED
ALONG THE CENTRAL COAST TONIGHT AND SUNDAY MORNING AS THE TROUGH
PASSAGE. IN ADDITION, A LIGHT NORTHEAST FLOW IS EXPECTED TO
DEVELOP THAT SHOULD LEAD TO SEVERAL DEGREES OF WARMING THERE,
ESPECIALLY ALONG THE COAST DUE TO THE DOWNSLOPING EFFECTS THERE.
HEIGHTS WILL START RISING FOLLOWING THE TROUGH PASSAGE MONDAY AND
TUESDAY. THIS IS EXPECTED TO BRING DOWN THE MARINE LAYER DEPTH
AND LEAD TO WARMING FOR AREAS SOUTH OF PT CONCEPTION. BY TUESDAY
SOME OF THE WARMER VALLEYS ARE EXPECTED TO REACH LOW END TRIPLE
DIGITS WHILE INLAND COASTAL AREAS WILL BE IN THE 80S TO AROUND 90.
ONE POSSIBLE CAVEAT FOR TUESDAY IS THAT THE 12Z NAM WAS MUCH MORE
AGGRESSIVE WITH THE RETURN OF MONSOON FLOW AND WAS HINTING AT AN
EARLIER START TO THE CONVECTION WITH CAPE VALUES OVER 1000J/KG,
MAINLY OVER THE COASTAL WATERS. THIS COULD BE A POTENTIAL DRY
LIGHTNING RISK SINCE THE DEEPER MONSOON MOISTURE WILL STILL BE
SOUTH OF THE AREA. WHILE A FEW OF THE ENSEMBLE SOLUTIONS SHOWED
SHOWERS AS EARLY AS TUESDAY ACROSS OUR AREA, MOST WERE WERE STILL
FAVORING WED OR THU AS THE MORE LIKELY START TO POSSIBLE
CONVECTION LOCALLY.
LONG TERM (WED-SAT)
13/218 PM.
STILL LOOKING LIKE A POTENTIALLY ACTIVE MONSOON PATTERN FOR THE
MIDDLE AND END OF NEXT WEEK. ENSEMBLES HAVE BEEN VERY CONSISTENT
WITH INCREASING PW'S NEXT WEEK, PEAKING ON THURSDAY BETWEEN 1.5
AND 2" ACROSS LA COUNTY AND AS HIGH AS AN INCH ACROSS THE CENTRAL
COAST. THE THREAT OF THUNDERSTORMS WILL COVER THE ENTIRE FORECAST
AREA AND NOT JUST THE MOUNTAINS AND DESERTS. SHOWERS AND STORMS
COULD DEVELOP AT ANY TIME OF DAY OR NIGHT GIVEN THE AMPLE MOISTURE
AND INSTABILITY. THERE WILL BE A RISK OF FLASH FLOODING,
PARTICULARLY IN THE MOUNTAINS AND DESERTS, BUT EVEN LOWER
ELEVATIONS WILL BE AT RISK FOR BRIEF PERIODS OF HEAVY RAIN.
AT THE SAME TIME THE AIR MASS WILL BE WARMING UP AND WITH
INCREASING HUMIDITY THE CONCERN WILL BE FOR INCREASING HEAT RISK
FACTORS ACROSS REGION-WIDE. CONFIDENCE REMAINS RATHER LOW RIGHT
NOW DUE TO THE UNCERTAINTY OF THE CLOUD AND POSSIBLE RAIN/STORM
COVERAGE. THE MOST LIKELY DAYS FOR HEAT HAZARDS WOULD PROBABLY BE
TUE AND WED BEFORE THE DEEPER MOISTURE AND HIGHER RAIN/STORM
CHANCES ARRIVE.
AVIATION
14/0321Z.
AT 0016Z AT KLAX, THE MARINE LAYER WAS 1400 FT DEEP. THE TOP OF
THE INVERSION WAS AT 3500 FT WITH A TEMPERATURE OF 23 C.
HIGH CONFIDENCE IN KPMD AND KWJF TAFS.
LOW TO MODERATE CONFIDENCE IN ALL COASTAL AND VALLEY TAFS DUE TO
PATCHY NATURE OF CLOUDS, ESPECIALLY FOR SITES SOUTH OF POINT
CONCEPTION.
TIMING OF CIG/VSBY RESTRICTIONS MAY BE OFF BY 2 HOURS & FLIGHT
CATEGORIES MAY BE OFF BY ONE CAT AT TIMES WHEN CIGS ARE PRESENT.
CIGS MAY ALSO FORM, SCATTER, AND REFORM MULTIPLE TIMES THROUGHOUT
THE NIGHT. THERE IS A CHC FOR NO LOW CLOUDS AT KPRB (30%), KBUR
(15%), AND KVNY (15%). THERE IS A 20% CHANCE OF NO VFR TRANSITIONS
AT KOXR, KLAX, AND KSMO THROUGH THE PERIOD.
KLAX...MODERATE CONFIDENCE IN TAF. ARRIVAL AND CLEARING TIMES MAY
BE OFF BY +/- 3 HOURS, AND MAY SCATTER AND REFORM MULTIPLE TIMES
OVERNIGHT. THERE IS A 20% CHANCE OF NO VFR TRANSITION THROUGH THE
PERIOD. THERE IS A 10% CHANCE OF A SOUTHEAST WIND COMPONENT
REACHING 8 KT 10Z-17Z SUN.
KBUR...MODERATE CONFIDENCE IN TAF. ARRIVAL AND CLEARING TIMES MAY
BE OFF BY +/- 2 HOURS. HOWEVER, THERE IS A 15% CHANCE FOR NO LOW
CLOUDS TONIGHT.
MARINE
13/207 PM.
SMALL CRAFT ADVISORY (SCA) LEVEL NW WINDS (20-30 KTS) WILL IMPACT
THE OUTER WATERS AND THE NEARSHORE WATERS ALONG THE CENTRAL COAST
THROUGH LATE SUNDAY NIGHT, PEAKING IN THE AFTERNOON AND EVENING
HOURS, WITH RELATIVE LULLS EACH MORNING. THERE IS A 50% CHANCE FOR
GALE FORCE WINDS (34-38 KTS) SUNDAY AFTERNOON THROUGH EVENING FOR
THE NORTHERN OUTER WATERS BEYOND 20 NM FROM SHORE. CHANCES FOR
GALES NEARSHORE TO 20 NM AWAY FROM SHORE ARE 25%. WILL LET THE
AFTERNOON OR OVERNIGHT SHIFT DETERMINE WHETHER OR NOT A GALE
WARNING IS NEEDED FOR PZZ670. SEAS ARE EXPECTED TO BECOME SMALL
EARLY NEXT WEEK, BEFORE BUILDING TO 6 TO 8 FEET THURSDAY INTO
FRIDAY. CONDITIONS ARE EXPECTED TO STAY BELOW ADVISORY LEVELS ON
MONDAY AND TUESDAY.
FOR THE INNER WATERS SOUTH OF POINT CONCEPTION, SCA LEVEL WIND
GUSTS ARE LIKELY ACROSS THE WESTERN PORTION OF THE SANTA BARBARA
CHANNEL THROUGH MIDNIGHT. THEREAFTER, CONDITIONS ARE GENERALLY
EXPECTED TO REMAIN SUB-ADVISORY THRU AT LEAST TUESDAY. LOCAL SCA
LEVEL WIND GUSTS CANNOT BE RULED OUT.
AN UPPER-LEVEL LOW WILL DRAW SUB-TROPICAL MOISTURE NORTHWARD
ACROSS THE COASTAL WATERS MID-WEEK, BRINGING CHANCES FOR SHOWERS
AND THUNDERSTORMS. WILL CONTINUE TO MONITOR THE SITUATION, AND
IRON OUT THE DETAILS AS WE GET CLOSER.
LOX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 PM PDT SUNDAY FOR ZONE
670. (SEE LAXMWWLOX).
GALE WATCH IN EFFECT FROM SUNDAY AFTERNOON THROUGH LATE
SUNDAY NIGHT FOR ZONE 670. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT MONDAY FOR
ZONES 673-676. (SEE LAXMWWLOX).
PUBLIC...MW/KL
AVIATION...LUND
MARINE...BLACK
SYNOPSIS...MW/KL
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
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