307
FXUS66 KLOX 212132
AFDLOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
232 PM PDT MON APR 21 2025
SYNOPSIS
21/125 PM.
ONSHORE FLOW WILL STRENGTHEN THROUGH THE WEEK AND BRING A COOLING
TREND THROUGH FRIDAY. NIGHT THROUGH MORNING LOW CLOUDS AND FOG
WILL BE A STAPLE OF THE FORECAST, STRUGGLING TO CLEAR FROM
BEACHES EACH DAY. NIGHT THROUGH MORNING DRIZZLE IS POSSIBLE TOWARD
MID-TO-LATE WEEK AS THE MARINE LAYER DEPTH DEEPENS SUBSTANTIALLY.
GUSTY ONSHORE WINDS ARE POSSIBLE ACROSS THE INTERIOR PORTIONS FOR
THE LATTER HALF OF THE WEEK.
SHORT TERM (TDY-THU)
21/154 PM.
A SERIES OF WEAK TO MODERATE UPPER LEVEL TROUGHS MOVING THROUGH
THE WEST COAST THIS WEEK WILL MAINTAIN COOLER THAN NORMAL
TEMPERATURES ACROSS COAST AND COASTAL VALLEYS THIS WEEK. THE
MARINE LAYER DEPTH THIS MORNING WAS AROUND 1400 FEET AND FORECAST
SOUNDINGS INDICATE ADDITIONAL DEEPENING OF 500 TO 1000 FEET EACH
DAY THROUGH AT LEAST THURSDAY. SO WHILE CLOUDS WERE MOSTLY
CONFINED TO THE COASTAL AREAS THIS MORNING, LOW CLOUDS AND FOG
WILL EASILY MAKE IT INTO THE VALLEYS OVERNIGHT TONIGHT AND THEN
AGAIN EACH NIGHT THE REST OF THE WEEK. AND AS USUAL WITH A
DEEPENING MARINE LAYER AND INCREASING ONSHORE FLOW, DAYTIME
TEMPERATURES WILL BE COOLING WITH HIGHS MOSTLY JUST IN THE 60S FOR
COAST/VALLEYS BY NO LATER THAN WEDNESDAY. MAY EVENTUALLY SEE SOME
MORNING DRIZZLE AS THE MARINE LAYER DEEPENS, ESPECIALLY THE LATTER
HALF OF THE WEEK WHEN THE STRONGEST OF THE TROUGHS MOVES THROUGH
THE AREA.
FAR INTERIOR AREAS LIKE THE ANTELOPE VALLEY AND INTERIOR SLO
COUNTY WILL BE COOLING DOWN AS WELL AS SOME OF THAT COOLER
MARITIME AIR PUSHES FARTHER INLAND BUT IT WILL TAKE UNTIL AT LEAST
WEDNESDAY FOR HIGHS THERE TO DROP BELOW NORMAL.
WITH THE INCREASE IN ONSHORE FLOW TO CLOSE TO 9MB TO THE DESERT
EACH AFTERNOON, THERE WILL BE INCREASING WEST TO SOUTHWEST WINDS
THERE GUSTING TO AROUND 40 MPH.
LONG TERM (FRI-MON)
21/215 PM.
THE COOL PATTERN WILL CONTINUE THROUGH THE WEEKEND AS THE
STRONGEST OF THE TROUGHS MOVES THROUGH SATURDAY WHICH WILL LIKELY
BE THE COOLEST DAY. THERE'S STILL QUITE A BIT OF DISAGREEMENT IN
THE MODELS WITH REGARD TO HOW DEEP THE UPPER WILL BE AND WHETHER
THERE WILL BE ANY PRECIPITATION BEYOND JUST THE TYPICAL MORNING
DRIZZLE. THE EPS ENSEMBLES HAVE BEEN PRETTY CONSISTENT THE LAST
FEW RUNS INDICATING AT LEAST A 60-70% CHANCE OF LIGHT RAIN NORTH
OF PT CONCEPTION DROPPING TO AROUND 10-20% IN THE SOUTH. AMOUNTS
WOULD BE UNDER A TENTH OF AN INCH IN MOST AREAS. TEMPERATURES
AGAIN JUST IN THE 60S WITH MINIMAL AFTERNOON CLEARING FOR COAST
AND VALLEYS.
A SLOW WARMING TREND WILL BEGIN SUNDAY BUT HIGH TEMPERATURES WILL
REMAIN BELOW NORMAL THROUGH AT LEAST EARLY NEXT WEEK.
AVIATION
21/1754Z.
AT 1708Z AT KLAX, THE MARINE INVERSION WAS AROUND 1500 FEET DEEP.
THE TOP OF THE INVERSION WAS 2900 FEET WITH A TEMPERATURES OF 15
DEGREES CELSIUS.
LOW CONFIDENCE IN MINIMUM FLIGHT CAT AT KBUR/KVNY, BUT HIGH
CONFIDENCE IN CIGS ARRIVING LATER TONIGHT. ARRIVAL TIME MAY BE OFF
+/- 3 HOURS AND MINIMUM FLIGHT CAT MAY BE OFF BY 1 FLIGHT CAT.
MODERATE TO HIGH CONFIDENCE IN REMAINING TAFS. THERE IS A 20-40%
CHANCE CHANCE FOR MVFR CONDS TO BE MINIMUM FLIGHT CAT AT VENTURA
AND LA COUNTY COASTAL SITES THROUGH THE PERIOD ONCE CIGS ARRIVE.
MVFR CIGS MAY BOUNCE IN AND OUT THIS AFTERNOON/EVENING, BUT CIGS
MAY ARRIVE AND REMAIN IN PLACE THROUGH TOMORROW MORNING AS EARLY
AS 00Z.
KLAX...MODERATE CONFIDENCE IN 18Z TAF. MVFR CIGS MAY BOUNCE IN AND
OUT AT ANY POINT THIS AFTERNOON/EVENING, WITH A 40% CHANCE CIGS
TO ARRIVE AS EARLY AS 00Z AND REMAIN IN PLACE THROUGH THE MORNING.
THERE IS A 30% CHANCE CIGS REMAIN OVC010 OR HIGHER THROUGH THE
PERIOD ONCE CIGS ARRIVE. NO SIGNIFICANT EAST WIND COMPONENT IS
EXPECTED.
KBUR...MODERATE CONFIDENCE IN 18Z TAF. HIGH CONFIDENCE IN CIGS
REACHING THE TERMINAL LATE TONIGHT, BUT LOW CONFIDENCE IN MINIMUM
FLIGHT CAT. ARRIVAL TIME MAY BE OFF +/- 3 HOURS. 20% CHANCE FOR
VV001-002 AND/OR VSBYS LESS THAN 1/2SM ONCE CIGS ARRIVE.
MARINE
21/127 PM.
FOR THE OUTER WATERS, HIGH CONFIDENCE IN CURRENT FORECAST.
THROUGH TONIGHT, THERE IS A 10% CHANCE OF LOCAL SMALL CRAFT
ADVISORY (SCA) LEVEL WIND GUSTS, MAINLY AROUND POINT CONCEPTION.
FOR TUESDAY, THERE IS A 30% CHANCE OF SCA LEVEL WINDS IN THE
NORTHWESTERN OUTER WATERS IN THE AFTERNOON AND EVENING. FOR
WEDNESDAY THROUGH FRIDAY, THERE IS A 50-70% CHANCE OF SCA LEVEL
WINDS, ESPECIALLY IN THE AFTERNOON AND OVERNIGHT HOURS.
FOR THE INNER WATERS NORTH OF POINT SAL, HIGH CONFIDENCE IN
CURRENT FORECAST. THIS AFTERNOON THROUGH TUESDAY, HIGH CONFIDENCE
IN WINDS AND SEAS REMAINING BELOW SCA LEVELS. FOR WEDNESDAY
THROUGH FRIDAY, THERE IS A 30-50% CHANCE OF SCA LEVEL WINDS,
MAINLY IN THE LATE AFTERNOON THROUGH EVENING HOURS.
FOR THE INNER WATERS SOUTH OF POINT CONCEPTION, HIGH CONFIDENCE
IN CURRENT FORECAST. TODAY THROUGH FRIDAY, HIGH CONFIDENCE IN
WINDS AND SEAS REMAINING BELOW SCA LEVELS ACROSS MOST AREAS. THE
ONLY EXCEPTION WILL BE THE WESTERN HALF OF THE SANTA BARBARA
CHANNEL WHERE THERE IS A 40-60% CHANCE OF SCA LEVEL WINDS
WEDNESDAY THROUGH FRIDAY, MAINLY DURING THE LATE AFTERNOON THROUGH
EVENING HOURS.
CHANCES FOR SCA CONDS INCREASE OVER THE WEEKEND FOR THE ENTIRE
COASTAL WATERS.
LOX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...MW
AVIATION...LEWIS
MARINE...LEWIS
SYNOPSIS...HALL
WEATHER.GOV/LOSANGELES
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