885
FXUS66 KLOX 160647
AFDLOX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1147 PM PDT THU MAY 15 2025
UPDATED AVIATION SECTION
SYNOPSIS
15/706 PM.
A COOLING TREND IS EXPECTED FRIDAY THROUGH THE WEEKEND WITH SOME
MORNING DRIZZLE POSSIBLE SATURDAY. MUCH WARMER TEMPERATURES ARE
EXPECTED NEXT WEEK, ESPECIALLY INLAND AS HIGH PRESSURE BUILDS OVER
THE REGION.
SHORT TERM (THU-SUN)
15/819 PM.
***UPDATE***
ONSHORE GRADIENTS COMBINED WITH A COASTAL EDDY AND WEAK TROUGHING
ALOFT SHOULD HELP TO CREATE A DEEPER AND MORE WIDESPREAD MARINE
LAYER TONIGHT. LOW CLOUDS ARE EXPECTED TO DEVELOP FOR MOST COASTAL
AREAS, AGAIN MOST WIDESPREAD ACROSS THE SANTA BARBARA PORTION OF
THE CENTRAL COAST AND THE LA BASIN, EXTENDING INLAND TO THE
ADJACENT COASTAL VALLEYS. LOW CLOUD COVERAGE FOR THE VENTURA COAST
AND ESPECIALLY THE SANTA BARBARA SOUTH COAST IS LESS CERTAIN, BUT
BELIEVE THAT THE WESTERN PORTION OF THE OXNARD PLAIN AND THE
EASTERN SBA SOUTH COAST WILL SEE LOW CLOUDS LATER TONIGHT INTO
EARLY FRIDAY. GUSTY WEST TO NORTHWEST WINDS CONTINUE THIS EVENING
OVER PORTIONS OF THE AREA, BUT WEAKER THAN ON PREVIOUS DAYS AND
WELL BELOW ADVISORY LEVEL. THE WINDIEST AREAS CONTINUE TO BE SW
SANTA BARBARA COUNTY AND THE INTERIOR SECTIONS, INCLUDING THE
ANTELOPE VALLEY AND INTERIOR SAN LUIS OBISPO COUNTY.
HIGH TEMPERATURES ON FRIDAY ARE EXPECTED TO LOWER A FEW DEGREES,
ANYWHERE FROM 2 TO 6 DEGREES COOLER FOR THE VALLEYS WITH LITTLE
CHANGE FOR THE COAST AND DESERTS. COASTAL LOW CLOUDS AND FOG
SHOULD CLEAR BY LATE MORNING, WITH CLEAR TO PARTLY CLOUDY SKIES IN
THE AFTERNOON.
***FROM PREVIOUS DISCUSSION***
GRADIENTS ARE STARTING TO TREND ONSHORE TODAY AS THE LAST IN A
SERIES OF MOSTLY WEAK TROUGHS MOVES THROUGH THE WEST COAST,
PEAKING LOCALLY ON SATURDAY. TEMPERATURES TODAY ENDED UP BEING
QUITE A BIT WARMER ACROSS THE INTERIOR, BUT LITTLE CHANGED NEAR
THE COAST.
AS THAT TROUGH ADVANCES SOUTHEAST THROUGH NORTHERN AND CENTRAL
CALIFORNIA FRIDAY AND SATURDAY, ONSHORE FLOW WILL CONTINUE TO
INCREASE AND PEAK SATURDAY AFTERNOON AT AROUND 9MB WITH COOLING
TEMPERATURES EACH DAY. AT THE SAME TIME, COOLING ALOFT WILL DEEPEN
THE MARINE LAYER CONSIDERABLY. LATEST FORECAST SOUNDING ACROSS
THE LA BASIN INDICATE THE MARINE INVERSION DEPTH RISING TO AROUND
2000 FEET FRIDAY, THEN UP TO 4000 FEET SATURDAY MORNING WITH A
SOLID 5MB GRADIENT. THIS COMBINATION OF FACTORS OFTEN, THOUGH NOT
ALWAYS, RESULTS IN SOME DRIZZLE ACROSS THE COAST AND VALLEYS. THE
ONE DRAWBACK IN THIS CASE IS THE UPPER LOW IS ACTUALLY TAKING A
MORE INSIDE PATH THROUGH CALIFORNIA WITH NORTHWEST FLOW ALOFT.
MOST OF THE MODELS DO FAVOR A RAPIDLY DEEPENING MARINE LAYER BUT
GIVEN THE INTERIOR TRAJECTORY AND WINDS ALOFT THE BEST CHANCES FOR
ANY DRIZZLE WOULD LIKELY BE THE SAN GABRIEL VALLEY IN EASTERN LA
COUNTY. FURTHER WEST IT WILL BE A BATTLE BETWEEN THE NORTHWEST
FLOW ALOFT AND THE MARINE LAYER EXPANDING FROM THE SOUTHEAST. BY
SATURDAY TEMPERATURES WILL AGAIN BE 5-15 DEGREES BELOW NORMAL.
GUSTY ONSHORE WINDS WILL DEVELOP IN THE AFTERNOON, ESPECIALLY
ACROSS THE ANTELOPE VALLEY.
WITH MODELS NOW IN AGREEMENT THAT THE FIRST TROUGH WILL TAKE A
MORE INLAND TRACK AND THE NEXT UPPER LOW ALSO MOVING FARTHER
INLAND THROUGH UTAH, THERE IS INCREASING CONFIDENCE THAT A SLOW
WARMING TREND WILL BEGIN SUNDAY WITH EARLIER CLEARING OF THE
MARINE LAYER, ESPECIALLY INLAND. MODEL FORECAST GRADIENTS ARE IN
LINE WITH THAT AS WELL INDICATING A 2-3MB OFFSHORE TREND.
LONG TERM (MON-THU)
15/208 PM.
CONFIDENCE REMAINS HIGH IN MUCH WARMER TEMPERATURES NEXT WEEK,
ESPECIALLY TUESDAY AND BEYOND AS HIGH PRESSURE BUILDS AND ONSHORE
FLOW WEAKENS. HIGHS IN THE 90S ARE EXPECTED IN THE VALLEYS AND
POSSIBLY SOME ISOLATED LOWER 100S ACROSS THE WESTERN SAN FERNANDO
VALLEY. INLAND COASTAL AREAS WILL AT LEAST REACH THE MID 80S AND
POSSIBLY LOWER 90S IN DOWNTOWN LA. WARMEST DAY ARE EXPECTED TO BE
TUE-THU, BUT WELL ABOVE NORMAL TEMPERATURES WILL CONTINUE AT LEAST
THROUGH NEXT FRIDAY. THERE STILL MAY BE A SHALLOW MARINE LAYER AT
THE COAST CREATING SOME AREAS OF DENSE FOG.
AVIATION
16/0646Z.
AROUND 05Z, THE MARINE LAYER DEPTH WAS AROUND 1300 FEET DEEP AT
KLAX. THE TOP OF THE MARINE INVERSION WAS AROUND 2200 FEET WITH A
TEMPERATURE AROUND 16 DEGREES CELSIUS.
MODERATE CONFIDENCE IN THE CURRENT FORECAST FOR COASTAL AND VALLEY
TERMINALS. HIGH CONFIDENCE IN THE CURRENT FORECAST FOR DESERT
TERMINALS. HIGHER CONFIDENCE EXISTS IN FLIGHT CATEGORIES. LESS
CONFIDENCE EXISTS IN TIMING. THERE IS A HIGH CHANCE THAT THE TIMING
OF CATEGORY CHANGES COULD BE OFF BY UP TO TWO HOURS. THERE IS A
MODERATE CHANCE THAT FLIGHT CATEGORIES COULD BE ONE CATEGORY LOWER
THAN FORECAST. THERE IS A LOW CHANCE THAT IMMEDIATE COASTAL
TERMINALS MAY NOT CLEAR ON FRIDAY.
KLAX...MVFR CONDITIONS WILL LIKELY SPREAD INTO KLAX THROUGH 08Z.
THERE IS A 30 PERCENT CHANCE THAT CONDITIONS COULD BE ONE CATEGORY
LOWER THROUGH 10Z. VFR CONDITIONS COULD DEVELOP AS SOON AS 19Z, OR
AS LATE AS 22Z. THERE IS 10 PERCENT CHANCE OF NO CLEARING AT ALL.
AN EARLY RETURN OF MVFR CONDITIONS SHOULD BE EXPECTED WITH LOWER
CONDITIONS ARRIVING AS SOON AS 23Z OR AS LATE AS 05Z SATURDAY. ANY
EASTERLY WINDS SHOULD BE LESS THAN 7 KNOTS, BUT THERE IS A 5
PERCENT CHANCE THAT EAST WINDS COULD RANGE BETWEEN 7 AND 10 KNOTS
BETWEEN 13Z AND 17Z.
KBUR...MVFR CONDITIONS WILL LIKELY SPREAD INTO KBUR AS EARLY AS
10Z, OR AS LATE AS 13Z. IF LOWER CONDITIONS DEVELOP THROUGH 13Z,
THERE IS A 40 PERCENT CHANCE THAT CONDITIONS COULD BE PRIMARILY IN
THE IFR CATEGORY. VFR CONDITIONS COULD DEVELOP AS SOON AS 15Z, OR
AS LATE AS 18Z. MVFR CONDITIONS COULD SPREAD IN AS SOON AS 03Z
SATURDAY, BUT MORE LIKELY AFTER 08Z.
MARINE
15/746 PM.
FOR THE OUTER WATERS, HIGH CONFIDENCE IN A COMBINATION OF SMALL
CRAFT ADVISORY (SCA) LEVEL WINDS AND SEAS (AT TIMES), WILL LULL IN
WINDS POSSIBLE IN THE MORNING HOURS THROUGH THE WEEKEND. THERE IS
A 40% CHANCE OF GALE FORCE NW WIND GUSTS FOR NORTHERN PORTIONS OF
PZZ670 LATE FRI AFTERNOON INTO THE EVENING HOURS. BETTER CHANCES
FOR GALES FOR THE WATERS AROUND POINT CONCEPTION, NORTHERN CHANNEL
ISLANDS, AND DOWN TO SAN NICOLAS SATURDAY EVENING THROUGH LATE
SUNDAY. SEAS WILL PEAK AROUND 13 FEET TOWARDS THE END OF THE
WEEKEND. THERE IS POTENTIAL FOR SCA WINDS AND SEAS TO PERSIST
THROUGH NEXT WEEK.
FOR THE INNER WATERS NORTH OF POINT SAL, THERE IS A 80% CHANCE OF
SCA LEVEL NW WINDS DURING THE AFTERNOON/EVE HOURS ON FRI - WITH A
30% CHANCE OF GALE FORCE WIND GUSTS ACROSS THE WATERS > 5 NM
OFFSHORE SAN SIMEON. FOR THE REMAINDER OF THE WEEKEND, HIGH
CONFIDENCE IN COMBINATION OF SCA LEVEL WINDS AND SEAS WITH A
30-50% CHANCE OF GALE FORCE WINDS DURING THE LATE AFTERNOON/EVE
HOURS ON SATURDAY AND SUNDAY. SEAS WILL BUILD TO AROUND 12 FEET
DURING THIS TIME. SEAS MAY FALL BELOW SCA LEVELS SOMETIME LATE MON
INTO MID-WEEK, WHILE THERE IS A MODERATE CHANCE FOR SCA LEVEL
WINDS DURING THE AFTERNOON/EVE HOURS EACH DAY.
FOR THE INNER WATERS SOUTH OF POINT CONCEPTION, THERE IS A 60%
CHANCE OF SCA LEVEL W WINDS ACROSS WESTERN PORTIONS OF THE SANTA
BARBARA CHANNEL FRI AFTERNOON/EVE. FOR THE REMAINDER OF THE
WEEKEND, HIGH CONFIDENCE IN SCA LEVEL WINDS. THERE IS ALSO A
40-50% CHANCE OF GALE FORCE WINDS ACROSS THE WESTERN HALF OF THE
SBA CHANNEL DURING THE LATE AFTERNOON/EVE HOURS ON SATURDAY AND
SUNDAY. STEEP AND CHOPPY SEAS AROUND 8 FEET ARE EXPECTED DURING
THIS TIMEFRAME. OTHER THAN LOW CHANCES ACROSS WESTERN SBA CHANNEL,
WINDS AND SEAS WILL LIKELY REMAIN BELOW SCA CRITERIA THROUGH MID-
WEEK.
LOX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT FRIDAY FOR ZONE
650. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT SATURDAY FOR
ZONES 670-673-676. (SEE LAXMWWLOX).
PUBLIC...MW
AVIATION...HALL
MARINE...BLACK
SYNOPSIS...MW/SMITH
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
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