044
FXUS66 KLOX 210528
AFDLOX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1028 PM PDT MON OCT 20 2025
UPDATED AVIATION SECTION
SYNOPSIS
20/547 PM.
THERE IS A CHANCE OF LOW CLOUDS AND DENSE FOG ALONG SOME COASTAL
SECTIONS TONIGHT INTO EARLY TUESDAY. THEN, A DEEPENING MARINE
LAYER WILL BRING LOW CLOUDS AND SOME DRIZZLE TO ALL OF THE COASTS
AND VALLEYS ON WEDNESDAY. MAX TEMPERATURES ON WEDNESDAY WILL FALL
DRAMATICALLY WITH HIGHS ONLY IN THE MID 60S TO LOWER 70S ACROSS
ALL OF THE COASTS AND VLYS. DRY AND WARMER CONDITIONS ARE SLATED
FOR THE END OF THE WEEK.
SHORT TERM (MON-THU)
20/812 PM.
***UPDATE***
A LARGE CLOSED LOW OVER THE WATERS IS CENTERED ABOUT 500 MILES
SOUTHWEST OF POINT CONCEPTION THIS EVENING. THE LOW IS FORECAST TO
GRADUALLY MOVE NEWD TOWARD THE COAST THROUGH EARLY WEDNESDAY
MORNING, THEN SHIFT DIRECTLY EAST AND OUT OF THE AREA BY EARLY
THURSDAY. SEE DETAILS BELOW FOR THUNDERSTORM CHANCES AS THE LOW
MOVES OVER THE AREA ON WEDNESDAY. HEIGHTS ALOFT WILL LOWER SLOWLY
AS THE LOW DRAWS CLOSER, ALLOWING MARINE LAYER CLOUDS TO EXPAND
AND EXTEND FURTHER INLAND EACH NIGHT. IN ADDITION, A COOLING TREND
IS EXPECTED WITH HIGHS LOWERING INTO THE 60S TO 70S BY WEDNESDAY.
FOR TONIGHT, THE MARINE LAYER IS STILL RELATIVELY SHALLOW, AND
THERE IS A CHANCE OF PATCHY DENSE FOG AGAIN ALONG THE CENTRAL
COAST. FURTHER SOUTH, COASTAL LOW CLOUDS ARE EXPECTED, ESPECIALLY
FOR THE VENTURA AND LA COASTS, BUT DENSE FOG IS UNLIKELY.
OTHERWISE, LOOKING FOR ANOTHER MOSTLY SUNNY AND PLEASANT DAY, WITH
HIGHS IN THE LOW 70S FOR MOST COASTAL AREAS, AND IN THE 80S
INLAND.
***FROM PREVIOUS DISCUSSION***
A CUT-OFF LOW PRESSURE SYSTEM THAT WAS LOCATED TO OUR SOUTHWEST
THIS AFTERNOON, IS POISED TO MOVE OVERHEAD WEDNESDAY BEFORE
DEPARTING EAST THURSDAY. WE HAVE HIGH CONFIDENCE IN COOLING AND
MOISTENING TRENDS THROUGH WEDNESDAY ASSOCIATED WITH A DEEPENING
MARINE LAYER.
THERE IS A 10-20 PERCENT CHANCE OF SHOWERS OR THUNDERSTORMS
FOCUSED ACROSS THE OCEAN TO SAN LUIS OBISPO COUNTY TUESDAY NIGHT,
BECOMING FOCUSED ACROSS THE INTERIOR MOUNTAINS OF SANTA BARBARA
AND VENTURA COUNTY WITH DRY LIGHTNING FIRE STARTS AND GUSTY WINDS
LIKELY BEING THE MAIN THREATS WITH ANY THUNDERSTORMS. ALTHOUGH WE
HIGHLIGHT SPECIFIC AREAS AND TIMES, CUT-OFF LOW PRESSURE SYSTEMS
ARE NOTORIOUSLY DIFFICULT TO FORECAST AND AS A RESULT A
THUNDERSTORM CANNOT BE RULED OUT ANYWHERE, ESPECIALLY AS THE
SYSTEM MOVES OVERHEAD ON WEDNESDAY. DRIZZLE IS ALSO LIKELY FOR
COASTAL AREAS TO COASTAL MOUNTAIN SLOPES, ESPECIALLY TUESDAY
EVENING THROUGH WEDNESDAY MORNING, ASSOCIATED WITH THE RAPIDLY
DEEPENING MARINA LAYER.
BREEZY WINDS ARE ANTICIPATED ESPECIALLY ACROSS HIGHER TERRAIN
WEDNESDAY INTO WEDNESDAY NIGHT, ALTHOUGH LIKELY REMAINING UNDER
ADVISORY LEVELS FOR MOST AREAS.
LONG TERM (FRI-MON)
20/159 PM.
A WARM UP IS EXPECTED THROUGH FRIDAY AHEAD OF OUR NEXT SYSTEM,
WHICH WILL PASS WELL TO OUR NORTH THIS WEEKEND. GUIDANCE CONTINUES
TO TREND DRIER WITH ONLY A 15-30 PERCENT CHANCE OF RAIN FOCUSED
SATURDAY NIGHT INTO SUNDAY FOR SAN LUIS OBISPO AND NORTHERN SANTA
BARBARA COUNTIES. ELSEWHERE, A DEEPENING MARINE LAYER COULD EKE
OUT SOME DRIZZLE. THE BIGGEST IMPACT MAY BE GUSTY WEST TO
NORTHWEST WINDS POTENTIALLY NEARING ADVISORY LEVELS FOCUSED ACROSS
THE HIGH TERRAIN AND SOUTHWEST SANTA BARBARA COUNTY. BEYOND THIS
SYSTEM THERE CONTINUES TO BE THE POTENTIAL FOR AT LEAST A MODERATE
NORTH TO OFFSHORE (SANTA ANA) WIND EVENT, ALTHOUGH GUIDANCE HAS
BACKED OFF OF THIS POTENTIAL A BIT. IT COULD BE A HOT ONE,
ESPECIALLY CLOSER TO THE COAST, AS A FAIRLY STOUT RIDGE FOR LATE
OCTOBER MAY BUILD OVERHEAD, FURTHER ADDING TO THE HEAT ASSOCIATED
WITH THE OFFSHORE FLOW.
AVIATION
21/0527Z.
AT 0459Z AT KLAX, THERE WAS A SURFACE INVERSION TO 1500 FEET WITH
A TEMPERATURE OF 24 DEGREES C.
HIGH CONFIDENCE IN TAFS FOR KPRB, KBUR, KVNY, KPMD, AND KWJF.
MODERATE CONFIDENCE IN TAFS FOR KSMX AND KSBP. CLEARING TIMES MAY
BE OFF +/- 1 HOUR.
LOW CONFIDENCE IN REMAINING TAFS. THERE IS A 40% CHANCE FOR LIFR
TO IFR CONDS, WITH LOCALIZED VLIFR VSBYS, AT KOXR, KCMA, KLAX,
KSMO, AND KLGB THROUGH 18Z, BUT ESPECIALLY FROM 12Z-17Z.
FOR ALL COASTAL AND COASTAL VALLEY SITES, LOWER CONFIDENCE AFTER
00Z WED DUE TO UNCERTAINTY OF CIG HEIGHT (+/-500 FEET) AND TIMING
(+/- 3 HOURS) AS A CUTOFF LOW WORKS ITS WAY INTO SOUTHERN
CALIFORNIA, WHICH SHOULD PROVIDE SIGNIFICANT LIFT TO THE MARINE
LAYER.
KLAX...LOW CONFIDENCE IN TAF. 40% CHANCE FOR VSBYS 1SM-5SM AND
OVC002-008 CIGS 10Z-18Z. AFTER 00Z WED, HIGH CONFIDENCE IN RETURN
OF LOW CLOUDS, BUT LOW CONFIDENCE IN CIG HEIGHTS (+/- 500 FEET)
AND TIMING (+/- 3 HOURS). NO SIGNIFICANT EAST WIND COMPONENT
EXPECTED.
KBUR...HIGH CONFIDENCE IN TAF.
MARINE
20/812 PM.
A LONG PERIOD NORTHWEST SWELL IS BRINGING 8-12 FOOT SEAS TO THE
OUTER WATERS AND NEARSHORE WATERS ALONG THE CENTRAL COAST, AND A
SMALL CRAFT ADVISORY (SCA) IN EFFECT THROUGH LATE TONIGHT FOR THE
HIGH SEAS IN THESE AREAS. THE ADVISORY WAS EXTENDED THROUGH
TUESDAY AFTERNOON BUT LOWER CONFIDENCE DUE TO POOR MODEL GUIDANCE.
THERE IS A CHANCE THAT THE ADVISORY WILL NEED TO BE CANCELED, BUT
SEAS LOOK TO RISE AND FALL THROUGHOUT THE WEEK, TO NEAR OR ABOVE
SCA LEVELS AT TIMES. SEAS ACROSS THE OUTER WATERS WILL THEN
INCREASE TO 11-13 FEET LATE FRIDAY THROUGH THE WEEKEND. SEAS ARE
EXPECTED TO REMAIN BELOW SCA LEVELS INSIDE THE SOUTHERN
CALIFORNIA BIGHT, ALTHOUGH STEEP AND CHOPPY WIND WAVES WILL OCCUR
WEDNESDAY.
HIGH CONFIDENCE IN WINDS REMAINING REMAINING RELATIVELY LIGHT
THROUGH WEDNESDAY MORNING, THEN NORTHWESTERLY WINDS WILL INCREASE
TO 20-30 KNOTS ACROSS THE WATERS SOUTH OF POINT CONCEPTION,
INCLUDING THE INNER WATERS (SCA LIKELY). WINDS INSIDE THE
SOUTHERN CALIFORNIA BIGHT WILL DECREASE LATE WEDNESDAY NIGHT, BUT
SCA LEVEL NORTHWESTERLY WINDS WILL CONTINUE ACROSS THE OUTER
WATERS AND EXPAND TO THE NORTH THURSDAY THROUGH FRIDAY.
PATCHY DENSE FOG IS LIKELY ACROSS PORTIONS OF THE COASTAL WATERS
TONIGHT INTO LATE TUESDAY MORNING.
LOX WATCHES/WARNINGS/ADVISORIES
CA...HIGH SURF ADVISORY IN EFFECT UNTIL 9 PM PDT WEDNESDAY FOR
ZONES 340-346. (SEE LAXCFWLOX).
PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 PM PDT TUESDAY FOR
ZONES 645-670-673-676. (SEE LAXMWWLOX).
PUBLIC...MUNROE
AVIATION...LEWIS
MARINE...LEWIS/SCHOENFELD/CC
SYNOPSIS...CILIBERTI
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
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