523
FXUS66 KLOX 241145
AFDLOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
445 AM PDT THU APR 24 2025
SYNOPSIS
24/444 AM.
A DEEP MARINE LAYER AND STRONG ONSHORE FLOW WILL KEEP A COOL
WEATHER PATTERN IN PLACE THROUGH FRIDAY. IT WILL BE MOSTLY CLOUDY
WITH PATCHY DRIZZLE EACH MORNING, THEN SKIES WILL PARTIALLY
CLEAR EACH AFTERNOON. AN UPPER LOW AND FRONTAL SYSTEM WILL LIKELY
BRING SOME RAIN TO THE AREA SATURDAY. AFTER THE UPPER LOW MOVES
EAST OF THE REGION, DRY WEATHER IS EXPECTED SUNDAY THROUGH MIDWEEK,
WITH A WARMING TREND.
SHORT TERM (TDY-SAT)
24/440 AM.
THE MARINE LAYER WAS ABOUT 4500 FEET DEEP ACROSS THE REGION EARLY
THIS MORNING, AND WITH STRONG ONSHORE GRADIENTS OF AROUND 7 MB
BETWEEN KLAX AND KDAG, LOW CLOUDS WERE WIDESPREAD IN ALL AREAS
FROM THE COASTAL SLOPES SOUTHWARD AND WESTWARD. CLOUDS HAVE EVEN
PUSHED INTO THE FAR INTERIOR VALLEYS OF SLO COUNTY AND THE CUYAMA
VALLEY. THERE MAY BE DRIZZLE AROUND THE AREA THIS MORNING,
ESPECIALLY IN THE FOOTHILLS SOUTH OF POINT CONCEPTION.
AN UPPER LOW WILL MOVE INTO A POSITION ABOUT 600 NM WEST OF
NORTHERN CA THIS AFTERNOON, WITH A TROUGH EXTENDING SOUTHWARD.
WITH STRONG ONSHORE GRADIENTS AND INCREASINGLY CYCLONIC FLOW
ALOFT, EXPECT RATHER SLOW CLEARING TODAY. IN FACT, SKIES MAY
STRUGGLE TO CLEAR, ESPECIALLY IN COASTAL/VALLEY AREAS SOUTH OF
PT. CONCEPTION. WITH SUCH A DEEP MARINE LAYER, CLOUDS MAY ACTUALLY
HAVE MORE DIFFICULTY CLEARING IN THE VALLEYS. MAX TEMPS TODAY
WILL BE SIMILAR TO THOSE ON WED, GENERALLY 5 TO 10 DEGREES BELOW
NORMAL FOR LATE APRIL IN AREAS W OF THE MOUNTAINS, AND LOCALLY 12
TO 15 DEGREES BELOW NORMAL IN THE VALLEYS. MAX TEMPS WILL BE
CLOSER TO NORMAL IN THE ANTELOPE VALLEY.
THE UPPER LOW WILL DROP SLOWLY SOUTHWARD THRU THE EASTERN PACIFIC
TONIGHT/FRI, TO A POSITION ABOUT 400 NM W OF PT. CONCEPTION FRI
AFTERNOON. EXPECT THE MARINE LAYER TO REMAIN VERY DEEP, WITH LOW
CLOUDS PUSHING INTO ALL AREAS EXCEPT FOR THE ANTELOPE VALLEY AND
THE MOUNTAINS ABOVE 5000 FT TONIGHT. ONCE AGAIN THERE COULD BE
SOME DRIZZLE LATE TONIGHT/FRI MORNING. EXPECT ANOTHER DAY OF SLOW
AND/OR INCOMPLETE CLEARING FRI. MAX TEMPS MAY ACTUALLY BE DOWN A
COUPLE OF DEGREES W OF THE MOUNTAINS ON FRI, WITH SIGNIFICANT
COOLING EXPECTED IN THE MOUNTAINS AND THE ANTELOPE VALLEY.
THE UPPER LOW WILL MOVE EASTWARD TOWARD PT CONCEPTION FRI NIGHT,
THEN IT IS FORECAST TO COME ONSHORE IN SAN LUIS OBISPO OR
SANTA BARBARA COUNTY SAT MORNING. IT WILL THEN LIFT NORTHEASTWARD
INTO THE SAN JOAQUIN VALLEY SAT AFTERNOON.
IT LOOKS AS THOUGH THERE WILL BE AN ORGANIZED FRONTAL SYSTEM WITH
THIS SYSTEM AS IT MOVES ACROSS THE REGION SAT. THERE IS A CHANCE
OF RAIN LATE FRI NIGHT ACROSS SLO AND SBA COUNTIES. RAIN IS LIKELY
ACROSS MUCH OF THE REGION SAT, MAINLY IN THE MORNING ACROSS SLO
AND SBA COUNTIES, AND LATE MORNING INTO THE AFTERNOON ACROSS VTU
AND L.A. COUNTIES. AS THE UPPER LOW LIFTS NORTHEASTWARD, THE
CHANCE OF RAIN WILL DECREASE QUICKLY, WITH THE CHANCE CONFINED
MAINLY TO AREAS SOUTH OF PT. CONCEPTION SAT EVENING. THERE WILL BE
INCREASING INSTABILITY ON SAT, AND THERE IS NON-ZERO CHANCE OF
THUNDERSTORMS, ESPECIALLY NORTH OF PT. CONCEPTION. AT THIS POINT,
THE CHANCE OF THUNDERSTORMS SEEMS TO LOW TO MENTION IN THE
OFFICIAL FORECAST. IT WILL BE VERY CHILLY FOR LATE APRIL ACROSS
THE AREA, WITH MAX TEMPS 10 TO 20 DEGREES BELOW NORMAL.
RAINFALL TOTALS OF ONE QUARTER TO ONE HALF INCH ARE POSSIBLE
ACROSS SLO AND SBA COUNTIES, WITH GENERALLY ONE TENTH TO ONE THIRD
OF AN INCH ACROSS L.A. AND VTU COUNTIES. SNOW LEVELS BE BETWEEN
4500 AND 5500 FEET SAT, AND A FEW INCHES OF SNOW MAY FALL AT
ELEVATIONS ABOVE 5500 FEET. AT THIS POINT, IT APPEARS THAT
SNOW LEVELS WILL BE TOO HIGH TO BRING SNOW TO HIGHER PORTIONS OF
INTERSTATE 5 NEAR THE GRAPEVINE, BUT THAT WILL HAVE TO BE WATCHED.
LONG TERM (SUN-WED)
24/435 AM.
THE UPPER LOW WILL MOVE EAST-NORTHEASTWARD ACROSS NEVADA AND INTO
NORTHERN UTAH SUN. AFTER MORNING CLOUDS, SKIES SHOULD BECOME PARTLY
CLOUDY. ALTHOUGH THERE WILL BE SOME WARMING, MAX TEMPS WILL STILL
BE 6 TO 10 DEGREES BELOW NORMAL IN MOST AREAS.
AN IMPULSE DROPPING SOUTHWARD ON THE BACKSIDE OF THE UPPER LOW WILL
KEEP A TROUGH IN PLACE OVER THE REGION SUN NIGHT/MON. HOWEVER, A
FEW DEGS OF WARMING IS LIKELY IN MOST AREAS AS HEIGHTS TREND UPWARD.
UPPER RIDGING WILL BRING MORE SIGNIFICANT WARMING TO THE REGION TUE,
ALONG WITH MOSTLY CLEAR SKIES. HEIGHTS WILL BEGIN TO LOWER WED, AND
ONSHORE FLOW WILL INCREASE. THIS MAY BRING SOME COOLING, ESPECIALLY
TO COASTAL AREAS.
AVIATION
24/1142Z.
AT 1104Z AT KLAX, THE MARINE LAYER WAS 3900 FEET DEEP. THE TOP OF
THE INVERSION WAS AROUND 5600 FEET WITH A TEMPERATURE OF 13 C.
HIGH CONFIDENCE IN DESERT TAFS (KPMD, KWJF).
MODERATE CONFIDENCE IN REMAINING TAFS. TIMING OF FLIGHT CAT
CHANGES MAY BE OFF +/- 2 HOURS. EXPECT PERIODS OF MVFR CIGS.
THERE IS A 30% CHANCE OF IFR CIGS AT KPRB THRU 16Z THURSDAY.
KLAX...MODERATE CONFIDENCE IN 12Z TAF. MVFR CIGS EXPECTED
BKN/OVC015-030, ESPECIALLY FRONT AND BACK END OF FCST PD, BUT
THERE IS A 15% CHANCE CIGS DO NOT CLEAR. THERE IS A 10% CHANCE OF
AN EAST WIND COMPONENT REACHING 8 KT FROM 11Z-17Z FRI.
KBUR...MODERATE CONFIDENCE IN 12Z TAF. THERE IS A 15% CHANCE OF
NO CLEARING THRU FCST PD.
MARINE
24/348 AM.
FOR THE OUTER WATERS, GOOD CONFIDENCE IN CURRENT FORECAST. THERE
IS A 60% CHANCE OF SMALL CRAFT ADVISORY (SCA) LEVEL NW WINDS FOR
THE WATERS AROUND POINT CONCEPTION DOWN TO THE NORTHERN CHANNEL
ISLANDS THUR AFTERNOON/EVE. ALSO, THERE IS A 40% CHANCE FOR PZZ676
IN THE EVENING. ELSEWHERE, GUSTS WILL LIKELY REMAIN JUST AT OR
BELOW SCA LEVELS. WIDESPREAD CHANCES FOR SCA CONDS LIKELY (70%)
SAT AFTERNOON THRU AT LEAST MON NIGHT. SEAS ARE EXPECTED TO REMAIN
BELOW SCA CRITERIA THRU THE WEEKEND.
FOR THE INNER WATERS NORTH OF PT. SAL, MODERATE TO HIGH
CONFIDENCE IN THE FORECAST. THERE IS A 60% CHANCE OF SCA LEVEL NW
WIND GUSTS ACROSS THE WATERS OFF SAN SIMEON THU AFTERNOON/EVE.
LOWER CHANCES AT 20% FRI AFTERNOON/EVE. POTENTIAL FOR WIDESPREAD
SCA WINDS DURING AFTERNOON/EVE HOURS SAT THRU MON. SEAS ARE
EXPECTED TO REMAIN BELOW SCA CRITERIA THRU THE WEEKEND.
FOR THE INNER WATERS SOUTH OF PT. CONCEPTION, MODERATE CONFIDENCE
IN THE FORECAST. THERE IS A 70% CHANCE OF SCA LEVEL W-NW WINDS
ACROSS THE SANTA BARBARA CHANNEL THU AFTERNOON/EVE. LOWER CHANCES
AT 40% ACROSS SBA CHANNEL ON FRI. POTENTIAL FOR WIDESPREAD SCA
LEVEL WINDS WILL BE HIGHEST ON SUNDAY (>80% SBA CHANNEL, 50-60%
PZZ655). AT THIS TIME, SCA WINDS WILL LIKELY STAY CONFINED TO
WESTERN PORTIONS OF SBA CHANNEL MON AFTERNOON/EVE. SEAS ARE
EXPECTED TO REMAIN BELOW SCA CRITERIA THRU THE WEEKEND.
LOX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY IN EFFECT FROM 3 PM THIS AFTERNOON TO 10
PM PDT THIS EVENING FOR ZONE 650. (SEE LAXMWWLOX).
PUBLIC...DB
AVIATION...BLACK
MARINE...BLACK
SYNOPSIS...DB
WEATHER.GOV/LOSANGELES
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