894
FXUS66 KLOX 041530
AFDLOX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
830 AM PDT THU SEP 4 2025
SYNOPSIS
04/221 AM.
A SLIGHT COOLING TREND WILL KNOCK A FEW DEGREES OFF THE DAYTIME
HIGHS THROUGH THE WEEKEND, BRINGING TEMPERATURES BACK TO NEAR
NORMAL LEVELS. THEN NEXT WEEK A LOW PRESSURE SYSTEM WILL ENCOMPASS
THE ENTIRE WEST COAST BRINGING TEMPERATURES DOWN TO 6 TO 12
DEGREES BELOW NORMAL. MONSOON MOISTURE IS NOT EXPECTED TO RETURN
FOR AT LEAST THE NEXT WEEK.
SHORT TERM (TDY-SAT)
04/829 AM.
***UPDATE***
LATEST SATELLITE SHOWS LOW CLOUDS OVER THE SOUTHERN SALINAS
VALLEY, SANTA MARIA VALLEY, SANTA YNEZ VALLEY, SANTA BARBARA CITY
AREA, AND ACROSS THE OXNARD PLAIN. THE MARINE LAYER IS EXPECT TO
RETREAT OVER THE NEXT SEVERAL HOURS. HOWEVER, LOW CLOUDS MAY
LINGER ALONG THE IMMEDIATE COAST THROUGH THE AFTERNOON FOR SLO/SBA
COUNTIES. THE FORECAST IS STILL ON TRACK WITH REGARDS TO TEMPS AND
HUMIDITY. SLIGHTLY ABOVE NORMAL TEMPERATURES WITH ABOVE NORMAL
HUMIDITY CAN BE EXPECTED THROUGH FRIDAY, WITH A COOLING TREND TO
BELOW NORMAL FOR MOST AREAS OVER THE WEEKEND.
PWS STILL LOOK TO BE A LIMITING FACTOR IN REGARDS TO CONVECTIVE
POTENTIAL THIS AFTERNOON HOWEVER, THERE IS STILL A 10-15% CHANCE
OF A THUNDERSTORM ACROSS THE SAN GABRIELS AND 5-10% FOR INTERIOR
VENTURA COUNTY MOUNTAINS. IF CONVECTIVE INITIATION OCCURS, THE
PRIMARY HAZARDS WOULD BE DRY LIGHTNING AND GUSTY WINDS. AS FOR
WINDS IN GENERAL, SUB-ADVISORY SUNDOWNERS AND GUSTY WINDS ACROSS
THE ANTELOPE VALLEY CAN BE EXPECTED EACH EVENING THROUGH THE
WEEKEND.
***FROM PREVIOUS DISCUSSION***
WEAKENING HIGH PRESSURE WILL CONTINUE THROUGH THE WEEKEND AS THE
PATTERN MAKES A SIGNIFICANT SHIFT FROM HOT AND HUMID CONDITIONS
TO MUCH COOLER AND LESS HUMID WEATHER NEXT WEEK. IN THE MEANTIME,
STILL EXPECTING MOST AREAS TO BE 1-4 DEGREES ABOVE NORMAL
THU/FRI WITH STILL ABOVE NORMAL HUMIDITY. THE NXK SOUNDING
YESTERDAY AFTERNOON SHOWED A MARKED DROP IN PW'S FROM THE LAST FEW
DAYS, DROPPING A HALF INCH FROM WEDNESDAY. THIS LIKELY WAS A
SIGNIFICANT REASON WHY THERE WAS MINIMAL AFTERNOON CONVECTION
ACROSS THE MOUNTAINS, AND EXPECTING SIMILAR IF NOT EVEN LESS
CUMULUS DEVELOPMENT TODAY. WE ARE SEEING A SLIGHT UPTICK IN
STRATUS ACROSS COASTAL LA/VENTURA COUNTIES THIS MORNING, AND EVEN
SNEAKING INTO THE SOUTHERN SALINAS VALLEY, AND WITH HIGH PRESSURE
CONTINUING TO WEAKEN OVER THE WEEKEND AND ONSHORE FLOW INCREASING,
LOW CLOUD COVERAGE IS EXPECTED TO EXPAND ACROSS MORE COASTAL
AREAS AND SOME OF THE VALLEYS.
LONG TERM (SUN-WED)
04/305 AM.
SUNDAY WILL LOOK AND FEEL A LOT LIKE SATURDAY, THOUGH THERE
REMAINS SEVERAL ENSEMBLE SOLUTIONS FAVORING A MINOR WARM UP OF
1-3 DEGREES AS HEIGHTS RISE SLIGHTLY IN RESPONSE TO THE PACNW
UPPER CONTINUING TO DROP SOUTH ALONG 140W. FOR THE MOST PART THIS
WILL JUST BE A MINOR DEVIATION IN WHAT IS EXPECTED TO BE THE
BEGINNING OF A LENGTHY COOLING TREND THAT WILL LAST THE REMAINDER
OF NEXT WEEK AS THAT UPPER LOW TAKES UP CAMP ALONG THE WEST COAST.
BY THE LATTER HALF OF THE WEEK THE UPPER LOW IS EXPECTED TO SIT
RIGHT ALONG THE NORTHERN CALIFORNIA COAST WITH 500MB HEIGHTS DOWN
TO AROUND 570DAM. THIS WILL PRODUCE A HEFTY DOSE OF ONSHORE FLOW
AND MARINE LAYER STRATUS THAT WILL MOST LIKELY PUSH WELL INTO THE
VALLEYS AND KEEP TEMPERATURES 6-12 DEGREES BELOW NORMAL. WOULD NOT
EVEN BE SURPRISED IF WE GET SOME COAST/VALLEY DRIZZLE AT TIMES AS
WELL WITH ONLY LIMITED CLEARING ALONG SOME OF THE BEACHES. GIVEN
THE STRONG SOUTHWEST FLOW ALOFT, MONSOON MOISTURE WILL BE PUSHED
OUT OF CALIFORNIA SO NO AFTERNOON CONVECTION IS EXPECTED NEXT
WEEK.
AVIATION
04/1003Z.
DUE TO A NATIONAL METAR OUTAGE, THERE WILL BE LIMITED OR NO
AMENDMENTS UNTIL OBSERVATIONS ARE RESTORED.
AROUND 0715Z, THE MARINE LAYER DEPTH WAS NEAR 900 FEET DEEP AT
KLAX. THE TOP OF THE MARINE INVERSION WAS AROUND 1700 FEET WITH A
TEMPERATURE NEAR 26 DEGREES CELSIUS. THERE WAS ANOTHER INVERSION
UP TO AROUND 2700 FEET.
HIGH CONFIDENCE IN THE CURRENT FORECAST FOR VALLEY AND DESERT
TERMINALS EXCEPT KPRB WHERE MODERATE CONFIDENCE EXISTS THROUGH
16Z. MODERATE CONFIDENCE EXISTS IN THE CURRENT FORECAST FOR
COASTAL TERMINALS THROUGH 16Z, AND AGAIN AFTER 03Z FRIDAY. THERE
IS A MODERATE TO HIGH CHANCE OF LIFR TO IFR CONDITIONS AT COASTAL
TERMINALS THROUGH 16Z, AND AGAIN AFTER 03Z TONIGHT. THERE IS A LOW
CHANCE OF SHOWERS AND THUNDERSTORMS AT DESERT TERMINALS BETWEEN
20Z AND 02Z.
KLAX...THERE IS A 30 PERCENT CHANCE OF IFR CONDITIONS THROUGH 16Z,
OTHERWISE VFR CONDITIONS WILL LIKELY PERSIST. ANY EASTERLY WINDS
WILL VERY LIKELY REMAIN LESS THAN 7 KNOTS.
KBUR...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. NO WIND
IMPACTS ARE EXPECTED AT THIS TIME.
MARINE
04/801 AM.
FOR THE WATERS SOUTHWEST THROUGH NORTHWEST OF THE CHANNEL ISLANDS
AND THE NEARSHORE WATERS ALONG THE CENTRAL COAST, THERE IS A
MODERATE CHANCE OF SMALL CRAFT ADVISORY (SCA) NORTHWEST WINDS
THIS MORNING INCREASING TO LIKELY THIS AFTERNOON. SCA LEVEL
WINDS ARE EXPECTED (STRONGEST DURING THE AFTERNOON AND EVENING
HOURS) THROUGH FRIDAY EVENING. THE HIGHEST CHANCE WILL BE FOR THE
WATERS BEYOND 10 NM OFFSHORE OF THE CENTRAL COAST. THERE IS A
MODERATE CHANCE OF SCA LEVEL WINDS EACH AFTERNOON AND EVENING OVER
THE WEEKEND, INCREASING TO A HIGH CHANCE FOR EARLY NEXT WEEK.
INSIDE THE SOUTHERN CALIFORNIA BIGHT, THERE IS A MODERATE CHANCE
OF SCA LEVEL WINDS EACH AFTERNOON AND EVENING ACROSS THE WESTERN
PORTION OF THE SANTA BARBARA CHANNEL AND INTO THE ANACAPA PASSAGE,
NEAR POINT DUME, AND INTO THE SAN PEDRO CHANNEL. WINDS AND SEAS
SHOULD DROP BELOW SCA LEVELS OVER THE WEEKEND, BUT START TO
INCREASE AGAIN EARLY NEXT WEEK.
LOX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY IN EFFECT FROM NOON TODAY TO 9 PM PDT
THIS EVENING FOR ZONE 645. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT SATURDAY FOR
ZONES 670-673-676. (SEE LAXMWWLOX).
PUBLIC...MW/BLACK
AVIATION...HALL
MARINE...HALL/SCHOENFELD
SYNOPSIS...MW
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
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