627
FXUS66 KLOX 241628
AFDLOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
928 AM PDT THU APR 24 2025
SYNOPSIS
24/911 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)
24/927 AM.
***UPDATE***
THE MARINE LAYER DEEPENED JUST SLIGHTLY SOUTH OF PT CONCEPTION
OVER NIGHT BUT COOLER AIR ALOFT ASSOCIATED WITH THE APPROACHING
TROUGH HAS WEAKENED THE INVERSION TO THE POINT WHERE SOME COASTAL
AREAS ARE ALREADY SEEING SIGNIFICANT BREAKS IN THE OVERCAST THIS
MORNING, MOST NOTABLY ACROSS SOUTHERN SANTA BARBARA COUNTY AND
EVEN COASTAL VENTURA COUNTY. ALSO, DRIZZLE HAS BEEN MUCH LESS
PREVALENT THIS MORNING WITH ONLY A COUPLE SPOTS REPORTING ANY
MEASURABLE RAIN.
THE CURRENT CLEARING PATTERN DOES STRONGLY SUGGEST A REVERSE
CLEARING SCENARIO TODAY SOUTH OF PT CONCEPTION. THIS MEANS LIKELY
BETTER CLEARING AT THE COAST THAN INLAND. A 2MB OFFSHORE TREND TO
THE EAST MAY ALSO PROVIDE SLIGHTLY BETTER CLEARING THAN YESTERDAY
AS WELL. ALONG THE CENTRAL COAST, THERE WAS VERY LITTLE CHANGE TO
THE MARINE LAYER DEPTH, HOWEVER THE CLEARING IS SLOWER THAN
YESTERDAY SO FAR DESPITE GRADIENTS THERE ALSO TRENDING ABOUT 2MB
OFFSHORE. EXPECT CLEARING THERE TO EVENTUALLY BE A LITTLE MORE
WIDESPREAD THAN YESTERDAY. EITHER WAY, LOOKING FOR TEMPERATURES TO
REMAIN 5-10 DEGREES BELOW NORMAL IN MOST AREAS EXCEPT THE HIGH
MOUNTAIN AREAS AND THE ANTELOPE VALLEY.
***FROM PREVIOUS DISCUSSION***
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
24/1616Z.
AT 1503Z AT KLAX, THE MARINE LAYER WAS 3900 FEET DEEP. THE TOP OF
THE INVERSION WAS AROUND 5500 FEET WITH A TEMPERATURE OF 11 C.
HIGH CONFIDENCE IN TAFS FOR KPMD AND KWJF.
MODERATE CONFIDENCE IN REMAINING TAFS. TIMING OF FLIGHT CAT
CHANGES MAY BE OFF +/- 3 HOURS, BUT GOOD CONFIDENCE IN CLEARING
AT ALL SITES BETWEEN 19Z AND 22Z. FLIGHT CATS MAY FREQUENTLY
BOUNCE BETWEEN MVFR AND VFR WHEN CIGS ARE PRESENT THROUGH 22Z AND
AGAIN AFTER 02Z. CIGS MAY ARRIVE TONIGHT AS VFR AND REMAIN OVC035
OR HIGHER THROUGH THE PERIOD DUE TO DEEPENING MARINE LAYER
OVERNIGHT.
KLAX...MODERATE CONFIDENCE IN TAF. BKN015-025 CIGS MAY BOUNCE IN
AND OUT THROUGH 22Z. OVC020-030 CIGS MAY ARRIVE AS EARLY AS 04Z OR
AS LATE AS 10Z. THERE IS A 20% CHANCE FOR VFR CIGS PREVAIL
OVERNIGHT INTO THE MORNING. NO SIGNIFICANT EAST WIND COMPONENT
EXPECTED.
KBUR...MODERATE CONFIDENCE IN TAF. TRANSITION TO MVFR CIGS
TONIGHT MAY BE AS EARLY 05Z OR AS LATE AS 10Z. THERE IS A 10%
CHANCE VFR CIGS PREVAIL OVERNIGHT INTO THE MORNING.
MARINE
24/757 AM.
FOR THE OUTER WATERS, MODERATE CONFIDENCE IN CURRENT FORECAST.
THERE IS A 50% CHANCE OF SMALL CRAFT ADVISORY (SCA) LEVEL NW
WINDS FOR THE WATERS AROUND POINT CONCEPTION DOWN TO SAN NICOLAS
ISLAND THIS AFTERNOON/EVE. SCA CONDS ARE NOT EXPECTED FRIDAY, THEN
THERE IS A 40% CHANCE SAT AFTERNOON/EVE. WIDESPREAD CHANCES FOR
SCA CONDS INCREASE (60-80%) SUN AFTERNOON THRU AT LEAST TUES
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 30% CHANCE OF SCA LEVEL NW
WIND GUSTS IN THE NORTHERN PORTION OF THE ZONE NEAR SAN SIMEON
THIS AFTERNOON/EVE. LOWER CHANCES AT 20% FRI AFTERNOON/EVE BEFORE
SLIGHTLY INCREASING FOR SAT AFTERNOON/EVE (30% CHANCE). POTENTIAL
FOR WIDESPREAD SCA WINDS INCREASES DURING AFTERNOON/EVE HOURS SUN
THRU TUES (50-70% CHANCE). 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 THIS AFTERNOON/EVE. LOWER
CHANCES AT 40% ACROSS SBA CHANNEL ON FRI AND SAT. CHANCES 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 AND TUES
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...MW/DB
AVIATION...LEWIS
MARINE...BLACK/LEWIS
SYNOPSIS...DB
WEATHER.GOV/LOSANGELES
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