258
FXUS66 KLOX 170650
AFDLOX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1150 PM PDT FRI MAY 16 2025
SYNOPSIS
16/833 PM.
STRONG ONSHORE FLOW AND A DEEP MARINE LAYER WILL BRING COOL
WEATHER THROUGH SATURDAY. GUSTY ONSHORE WINDS ARE EXPECTED IN THE
ANTELOPE VALLEY DURING THE AFTERNOON AND EVENING. NIGHT THROUGH
MORNING DRIZZLE OR LIGHT RAIN IS POSSIBLE SATURDAY. A WARMING
TREND WILL BE WILL BEGIN SUNDAY AND CONTINUE THROUGH NEXT WEEK AS
HIGH PRESSURE DEVELOPS. TEMPERATURES MORE TYPICAL OF THE SUMMER
SEASON ARE LIKELY AWAY FROM THE COAST FOR THE LATTER HALF OF NEXT
WEEK.
SHORT TERM (FRI-MON)
16/832 PM.
AN UNSEASONABLY STRONG UPPER LEVEL TROUGH WILL PUSH THROUGH
SOUTHWEST CALIFORNIA THIS WEEKEND. LOWERING HEIGHTS AND STRONGER
ONSHORE FLOW BROUGHT SOME COOLING TO MANY AREAS TODAY, WITH THIS
COOLING TREND EXPECTED TO CONTINUE INTO SATURDAY. CURRENT
SATELLITE IMAGERY SHOWING SOME UPPER LEVEL CLOUDS LOVING THROUGH
VENTURA AND LA COUNTIES THIS EVENING, WITH SOME LOW CLOUDS
RETURNING ACROSS PORTIONS OF THE COASTAL PLAIN. CURRENT ACARS
SOUNDING DATE SHOWING THE MARINE LAYER DEPTH ACROSS THE LA
BASIN RANGING BETWEEN 1500 AND 2000 FEET THIS EVENING.
THE APPROACHING UPPER LEVEL TROUGH COMBINED WITH THE
STRENGTHENING ONSHORE FLOW AND AN EDDY CIRCULATION IS EXPECTED TO
BRING A RAPIDLY DEEPENING MARINE LAYER OVERNIGHT INTO SATURDAY,
EVENTUALLY INCREASING TO 4000 TO 5000 FEET DEEP, HIGHEST IN LA
COUNTY. THIS RAPIDLY DEEPENING MARINE LAYER COMBINED WITH LIGHT
SOUTHERLY FLOW THROUGH THE BOUNDARY LAYER WILL MAKE CONDITIONS
FAVORABLE FOR AREAS OF LIGHT AND DRIZZLE, ESPECIALLY LA COUNTY.
THERE WILL BE A 10-20 PERCENT CHANCE OF MEASURABLE RAINFALL, WITH
HIGHEST POPS FAVORING THE LOWER COASTAL SLOPES AND FOOTHILLS.
CLEARING WILL BE SLOW TO NONE FOR MANY AREAS ON SATURDAY DUE TO
THE DEEPENING MARINE LAYER AND STRONGER ONSHORE FLOW. TEMPERATURES
WILL LIKELY STAY IN THE 60S IN MOST AREAS, WHICH WOULD BE 5-15
DEGREES BELOW NORMAL.
ONSHORE WINDS STARTING TO INCREASE THIS AFTERNOON AND EVENING
ACROSS THE INTERIOR, ESPECIALLY IN THE ANTELOPE VALLEY. WITH
THE DEEPENING UPPER LEVEL TROUGH BRINGING INCREASED UPPER LEVEL
WIND SUPPORT AND STRENGTHENING ONSHORE GRADIENTS, LOOKING FOR
STRENGTHENING ONSHORE WINDS ACROSS THE INTERIOR, ESPECIALLY
IN THE ANTELOPE VALLEY AND ADJACENT FOOTHILLS, WHERE A WIND
ADVISORY IS IN EFFECT ON SATURDAY FOR WIND GUSTS OF 45 TO 55 MPH.
SIMILAR STRONG WINDS ARE EXPECTED ON SUNDAY FOR THE ANTELOPE
VALLEY AND ADJACENT FOOTHILLS. THE INCREASED ONSHORE WINDS
ACROSS THE INTERIOR WILL BRING AN INCREASED RISK FOR LARGE GRASS
FIRES, ESPECIALLY IN THE ANTELOPE VALLEY, WHERE THERE WILL ALSO
BE THE POTENTIAL FOR REDUCED VISIBILITIES IN BLOWING DUST AND
SAND. GUSTY NORTHWEST TO NORTH WINDS WILL ALSO IMPACT SOUTHERN
SANTA BARBARA COUNTY AND THE I-5 CORRIDOR, WHERE WIND ADVISORIES
WILL LIKELY BE POSTED AT SOME POINT THIS WEEKEND.
*** FROM PREVIOUS DISCUSSION ***
THE WARMING TREND WILL CONTINUE MONDAY WITH SOME ADDITIONAL
OFFSHORE TRENDS LEADING TO SOME MORNING NORTHEAST WINDS ACROSS THE
HILLS AND MOUNTAINS AND POSSIBLY SOME OF THE VALLEYS AS WELL.
EXPECTING WIDESPREAD WARMING TRENDS OF 5-10 DEGREES OVER SUNDAY
AND SOME VALLEY AREAS AS MUCH AS 15 DEGREES WARMER, GETTING CLOSE
TO 90 DEGREES, INCLUDING INTERIOR SLO COUNTY AND THE WESTERN SAN
FERNANDO VALLEY.
LONG TERM (TUE-FRI)
16/225 PM.
NEXT WEEK IS GOING TO BE A HOT ONE AND LASTING AT LEAST TWO DAYS
LONGER THAN THE PREVIOUS HEAT WAVE. HIGHS ARE EXPECTING TO BE
FAIRLY SIMILAR TO THE LAST HEAT WAVE, TOPPING OUT IN THE LOW 100S
IN THE WARMER VALLEYS TUESDAY THROUGH, LOW 90S IN DOWNTOWN LA,
AND 80S ACROSS MOST OTHER AREAS EXCEPT THE BEACHES. THERE MAY
STILL BE A LINGERING SHALLOW MARINE LAYER MONDAY MORNING ACROSS
COASTAL LA COUNTY RESULTING IN SOME DENSE FOG BUT THAT SHOULD
CLEAR FAIRLY QUICKLY. IF THE FORECAST REMAINS ON TRACK, AND RIGHT
NOW CONFIDENCE IS HIGH, ANOTHER ROUND OF HEAT ADVISORIES WILL BE
NEEDED FOR THE COASTAL VALLEYS AND POSSIBLY EVEN PARTS OF THE
INTERIOR COASTAL PLAIN.
ONSHORE FLOW WILL START TO RETURN THURSDAY THAT WILL BEGIN A SLOW
COOLING TREND INTO NEXT WEEKEND.
AVIATION
17/0645Z.
AROUND 0530Z, THE MARINE LAYER DEPTH WAS AROUND 2200 FEET DEEP AT
KLAX. THE TOP OF THE INVERSION WAS AROUND 4200 FEET WITH A
TEMPERATURE NEAR 14 DEGREES CELSIUS.
MODERATE CONFIDENCE IN THE CURRENT FORECAST. THERE IS A HIGH
CHANCE THAT THE TIMING OF CATEGORY CHANGES COULD BE OFF BY UP TO
TWO TO FOUR HOURS. THERE IS A MODERATE CHANCE THAT FLIGHT
CATEGORIES COULD BE ONE CATEGORY LOWER THAN FORECAST BETWEEN 08Z
AND 16Z DUE TO DRIZZLE OR LIGHT RAIN. THERE IS A MODERATE CHANCE
OF COASTAL AND VALLEY TERMINALS BRIEFLY SCATTERING OUT ON
SATURDAY.
KLAX...MVFR CONDITIONS WILL LIKELY CONTINUE THROUGH AT LEAST 18Z,
AND POSSIBLY INTO 22Z. AFTER 18Z, THERE IS AN INCREASING CHANCE
OF VFR CONDITIONS WITH CEILINGS AT OR BELOW 5000 FEET. THERE IS A
40 PERCENT CHANCE THAT CONDITIONS COULD BE ONE CATEGORY LOWER
BETWEEN 08Z AND 16Z DUE TO DRIZZLE OR LIGHT RAIN. THERE IS A 30
PERCENT CHANCE OF BRIEF SCATTERING OUT BETWEEN 22Z SATURDAY AND
00Z SUNDAY. EASTERLY WINDS SHOULD REMAIN LESS THAN THAN 7 KNOTS
THROUGH 13Z, THEN THERE IS A 60 PERCENT CHANCE OF EASTERLY WINDS
BETWEEN 7 AND 10 KNOTS THROUGH 17Z OR 18Z.
KBUR...MVFR CONDITIONS WILL LIKELY CONTINUE THROUGH AT LEAST 18Z,
AND POSSIBLY INTO 20Z. AFTER 18Z, THERE IS AN INCREASING CHANCE
OF VFR CONDITIONS WITH CEILINGS AT OR BELOW 5000 FEET. THERE IS A
40 PERCENT CHANCE THAT CONDITIONS COULD BE ONE CATEGORY LOWER
BETWEEN 08Z AND 18Z DUE TO DRIZZLE OR LIGHT RAIN. THERE IS 30
PERCENT CHANCE OF BRIEF SCATTERING OUT BETWEEN 21Z SATURDAY AND
01Z SUNDAY.
MARINE
16/720 PM.
FOR THE OUTER WATERS THROUGH TUESDAY, HIGH CONFIDENCE IN
COMBINATION OF SMALL CRAFT ADVISORY (SCA) LEVEL WINDS AND SEAS.
FOR SATURDAY AFTERNOON THROUGH SUNDAY NIGHT, THERE IS A 60-80%
CHANCE OF GALE FORCE WINDS. GALES LOOK TO BE STRONGEST AND MOST
WIDESPREAD SUNDAY AFTERNOON THROUGH LATE SUNDAY NIGHT. THERE MAY
BE A LULL IN THE WINDS SUNDAY MORNING. SEAS WILL REACH 12-14 FEET.
ROUGH, SHORT PERIOD SEAS WILL EXIST INTO AT LEAST MONDAY.
FOR THE INNER WATERS (NORTH OF PT. SAL) THROUGH SUNDAY NIGHT,
HIGH CONFIDENCE IN SCA LEVEL WINDS LEADING UP TO THE GALE WARNING,
ESPECIALLY IN THE AFTERNOON AND EVENING HOURS. THERE IS A 80%
CHANCE OF GALE FORCE WINDS SATURDAY AFTERNOON/EVE INTO THE LATE
HOURS. THERE WILL BE A LULL IN THE WINDS SUN MORNING. ANOTHER GALE
WARNING IS LIKELY (60% CHANCE) FOR SUNDAY AFTERNOON AND EVENING.
FOR MONDAY THROUGH TUESDAY, THERE IS A 60-70% CHANCE OF SCA LEVEL
WINDS CONTINUING. SEAS WILL REACH 10-12 FEET. ROUGH, SHORT PERIOD
SEAS WILL EXIST INTO MONDAY.
FOR THE INNER WATERS (SOUTH OF POINT CONCEPTION) THROUGH SATURDAY
MORNING, HIGH CONFIDENCE IN WINDS AND SEAS REMAINING BELOW SCA
LEVELS. HOWEVER, THERE IS A 30% CHANCE OF SCA LEVEL WIND GUSTS FOR
FAR WESTERN PORTIONS OF SBA CHANNEL INTO THE LATE NIGHT HOURS
TONIGHT. FOR SATURDAY AFTERNOON THROUGH SUNDAY NIGHT, HIGH
CONFIDENCE IN SCA LEVEL WINDS FOCUSED MOSTLY THROUGH THE SANTA
BARBARA AND WESTERN SECTIONS OF THE SOUTHERN INNER WATERS.
ADDITIONALLY, THERE IS A 50-60% CHANCE OF GALE FORCE WINDS ACROSS
THE SANTA BARBARA CHANNEL SATURDAY EVENING THROUGH SATURDAY NIGHT.
THERE WILL BE A RELATIVE LULL IN THE WINDS OVERNIGHT, THEN
ANOTHER GALE WARNING IS LIKELY (50-60% CHANCE) FOR THE SANTA
BARBARA CHANNEL SUNDAY AFTERNOON INTO LATE NIGHT. SEAS MAY
APPROACH 8 FEET WITH SHORT PERIODS DUE TO THE WIND. FOR MONDAY
THROUGH TUESDAY, MODERATE CONFIDENCE IN WINDS AND SEAS REMAINING
BELOW SCA LEVELS.
LOX WATCHES/WARNINGS/ADVISORIES
CA...WIND ADVISORY NOW IN EFFECT FROM 10 AM SATURDAY TO 3 AM PDT
SUNDAY FOR ZONES 381-383. (SEE LAXNPWLOX).
PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 PM PDT SATURDAY FOR
ZONES 645-670-673-676. (SEE LAXMWWLOX).
GALE WARNING IN EFFECT FROM 3 PM SATURDAY TO 3 AM PDT SUNDAY
FOR ZONE 645. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT FROM NOON TO 6 PM PDT SATURDAY
FOR ZONE 650. (SEE LAXMWWLOX).
GALE WARNING IN EFFECT FROM 6 PM SATURDAY TO 3 AM PDT SUNDAY
FOR ZONE 650. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT FROM 6 PM SATURDAY TO 3 AM PDT
SUNDAY FOR ZONE 655. (SEE LAXMWWLOX).
GALE WARNING IN EFFECT FROM 3 PM SATURDAY TO 3 AM PDT MONDAY
FOR ZONES 670-673-676. (SEE LAXMWWLOX).
PUBLIC...GOMBERG/MW
AVIATION...HALL
MARINE...LEWIS/BLACK
SYNOPSIS...MW/HALL
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
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