134
FXUS66 KLOX 171621
AFDLOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
921 AM PDT FRI OCT 17 2025
SYNOPSIS
17/909 AM.
OFFSHORE FLOW WILL CONTINUE THROUGH SATURDAY AND KEEP A WARMER
AND DRIER PATTERN IN PLACE. BREEZY OFFSHORE WINDS WILL CONTINUE
THIS MORNING, ESPECIALLY THROUGH AND BELOW PASSES AND CANYONS. A
COOLING TREND WILL BEGIN SUNDAY AND CONTINUE MOST OF NEXT WEEK
WITH A RETURN OF LOW CLOUDS AND FOG TO THE COASTAL AREAS.
SHORT TERM (TDY-SUN)
17/920 AM.
***UPDATE***
OFFSHORE FLOW ENDED UP BEING ABOUT 30% WEAKER THAN FORECAST BUT
THERE ARE STILL SOME BREEZY NORTHEAST WINDS ACROSS PARTS OF
LA/VENTURA COUNTIES THIS MORNING. WINDS ARE MOSTLY UNDER 30 MPH
AND GENERALLY CONFINED TO THE VALLEYS AND MOUNTAINS. MAY STILL SEE
SOME LIGHT OFFSHORE BREEZES REACH THE VENTURA COUNTY COAST BUT AT
MOST AROUND 20MPH. THE BIGGEST IMPACT FROM THIS WEAK SANTA ANA
WILL BE THE WARMING TEMPERATURES. AT 9AM TEMPS ARE 5-15 DEGREES
WARMER THAN THURSDAY, WITH HIGHS PROJECTED TO BE IN THE UPPER 70S
AND 80S EXCEPT A LITTLE COOLER AT THE BEACHES. VERY LITTLE CHANGE
IN HIGHS SATURDAY.
***FROM PREVIOUS DISCUSSION***
IN WIND-SHELTERED AREAS, CLEARER SKIES AND DRY CONDITIONS WILL
PERMIT RADIATIVE COOLING PROCESSES TO BE MUCH MORE EFFICIENT
TONIGHT AND INTO SATURDAY MORNING. AS A RESULT, SATURDAY MORNING
COULD START OUT A LITTLE CHILLIER IN WIND-SHELTERED LOCATIONS,
SUCH AS THE OJAI AND SANTA YNEZ VALLEYS, AND ACROSS THE INTERIOR
PORTIONS OF THE AREA, SUCH AS THE ANTELOPE AND CUYAMA VALLEYS.
A COOLING TREND WILL START TO TAKE SHAPE ON SUNDAY AS OFFSHORE
FLOW STARTS TO BREAK DOWN AND BE REPLACED BY AN ONSHORE FLOW
REGIME. A RETURN OF NIGHT THROUGH MORNING LOW CLOUDS AND FOG COULD
RETURN AS SOON AS SUNDAY MORNING BUT MORE LIKELY FOR SUNDAY NIGHT
AND INTO MONDAY MORNING. WITH THE MARINE LAYER DEPTH RETURNING IN
A SHALLOW LAYER, DENSE FOG COULD BECOME A HAZARD TO START THE
WEEK FOR THE COASTAL AREAS.
LONG TERM (MON-THU)
17/252 AM.
ONSHORE FLOW WILL CONTINUE TO ESTABLISH THROUGH EARLY NEXT WEEK AS
A WEAK UPPER-LEVEL TROUGH TO THE SOUTHWEST OF THE REGION NEAR 30N
AND 125W WILL GRADUALLY LIFT OUT ACROSS THE REGION THROUGH
WEDNESDAY. WHILE THE DETERMINISTIC SOLUTIONS MOSTLY KEEP THE
REGION DRY WITH THIS TROUGH, ABOUT A FIFTH OF THE LATEST EPS
ENSEMBLE MEMBERS HAVE LIGHT PRECIPITATION DEVELOPING OVER THE AREA
BETWEEN TUESDAY AND WEDNESDAY. DESPITE THE OUTLIER NATURE OF THE
WETTER SOLUTIONS, IT SHOULD BE NOTED THAT TROUGHS TO THE SOUTHWEST
OF THE REGION ARE TYPICALLY NOT MODELED CORRECTLY. DUE TO THE
DATA-SPARSE REGION, LOW PRESSURE AREAS TO THE SOUTHWEST OF THE
REGION ARE A PROBLEMATIC FEATURE TO MODEL. IT IS NOT SURPRISING
TO SEE THE AI SOLUTIONS OF THE EPS TO HAVE EVEN MORE MEMBERS WITH
PRECIPITATION. CONFIDENCE IS HIGH IN A DEEP MARINE LAYER WITH
COOLER TEMPERATURES, BUT CAUTION SHOULD USED IN THE PRECIPITATION
FORECAST. FOR NOW, NBM VALUES REMAIN IN THE FORECAST, BUT THIS
WRINKLE IN THE FORECAST WILL LIKELY NEED SOME TIME TO GET IRONED
OUT.
AVIATION
17/1530Z.
AT 1500Z AT KLAX, 1Z, THE MARINE LAYER WAS 400 FT DEEP. THE TOP
OF THE INVERSION WAS AT 1900 FT WITH A TEMPERATURE OF 20 DEGREES
CELSIUS.
OVERALL FOR THE 18Z TAF PACKAGE, HIGH CONFIDENCE IN FORECASTS FOR
MOST SITES AS CAVU CONDITIONS ARE EXPECTED. THE ONLY EXCEPTION
WILL BE KPRB WHERE THERE IS MODERATE CONFIDENCE IN THE DEVELOPMENT
OF CIG AND/OR VSBY RESTRICTIONS AFTER 12Z.
WEAK OFFSHORE WINDS THIS MORNING MAY GENERATE SOME LIGHT
TURBULENCE AND LLWS THROUGH THE PASSES AND CANYONS.
KLAX...OVERALL, HIGH CONFIDENCE IN CURRENT FORECAST AS CAVU
CONDITIONS ARE EXPECTED THROUGH THE PERIOD. THERE IS A 5-10%
CHANCE OF LIFR/VLIFR CONDITIONS 11Z-16Z. NO SIGNIFICANT EASTERLY
WIND COMPONENT IS EXPECTED.
KBUR...HIGH CONFIDENCE IN 18Z TAF AS CAVU CONDITIONS ARE EXPECTED
THROUGH THE PERIOD.
MARINE
17/830 AM.
OVERALL, HIGH CONFIDENCE IN CURRENT FORECAST FOR ALL THE COASTAL
WATERS. TODAY THROUGH TUESDAY, WINDS AND SEAS ARE EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY (SCA) LEVELS. THERE WILL BE A
GOOD CHANCE OF SOME PATCHES OF DENSE FOG THIS WEEKEND INTO EARLY
NEXT WEEK.
LOX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...MW/HALL
AVIATION...RAT
MARINE...RAT
SYNOPSIS...MW/HALL
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
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