762
FXUS66 KLOX 080943
AFDLOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
243 AM PDT THU OCT 8 2026
SYNOPSIS
08/242 AM.
TODAY WILL BE THE LAST DAY OF THE LONG LASTING HEAT WAVE.
ALTHOUGH AFTERNOON HIGH TEMPERATURES WILL BE A FEW DEGREES COOLER
THAN YESTERDAY THEY WILL STILL BE DANGEROUSLY HIGH. TEMPERATURES
WILL TREND COOLER FRIDAY INTO SUNDAY AND THERE WILL BE AN
INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS DUE TO MOISTURE
FROM HURRICANE RACHEL.
SHORT TERM (TDY-SAT)
08/242 AM.
TODAY WILL BE THE LAST DAY OF THE LONG DURATION HEATWAVE THAT HAS
PLAGUED SRN CA SINCE THE BEGINNING OF THE MONTH. IT WILL ALSO BE
COOLER THAN THE PREVIOUS DAYS AS HGT LOWER WITH THE WEAKENING
UPPER HIGH AND STRENGTHENING ONSHORE FLOW. A SHALLOW MARINE LAYER
STRATUS DECK HAS MOVED THROUGH THE SBA CHANNEL FROM THE OUTER
WATERS AND THERE WILL BE LOW CLOUDS AND PATCHY DENSE FOG AT MANY
OF THE BEACHES ESP NORTH OF MALIBU. MOST MAX TEMPS WILL FALL BY 2
TO 3 DEGREES TODAY ALTHOUGH UP TO 6 DEGREES OF COOLING IS POSSIBLE
IN THE NEARSHORE AREAS.
CHANGES WILL REALLY BECOME NOTICEABLE ON FRIDAY AS AN UPPER LOW
DEVELOPS TO THE WEST OF PT CONCEPTION AND BEGINS TO MOVE TO THE
EAST. HGTS WILL FALL THROUGH THE DAY TO 580 DAM. AT THE SAME TIME
AN EARLY SEASON COLD UPPER LOW WILL BEGIN TO MOVE OUT OF CANADA
AND INTO WASHINGTON STATE. ONSHORE FLOW WILL CONTINUE TO INCREASE
AND THERE SHOULD BE A FAIRLY ROBUST MARINE LAYER CLOUD DECK
COVERING MOST OF THE COASTS AND SOME OF THE LOWER VLYS. MOST TEMPS
WILL FALL BY ABOUT 6 DEGREES, BUT THE NEAR SHORE AREA WILL NOT SEE
MUCH CHANGE AS THOSE AREAS WILL SEE THE BEST COOLING TODAY.
THINGS GET REALLY INTERESTING ON SATURDAY AS MAJOR TROFFING WILL
DEVELOP ACROSS ALL OF THE WEST COAST AND SET UP SW FLOW ACROSS THE
ENTIRE STATE AND THE BAJA PENINSULA. THIS SW FLOW WILL STEER TS
RACHEL TO THE NE AND BY LATE AFTERNOON RACHEL SHOULD BE ~450 S OF
SAN DIEGO. IT WILL BE A MOSTLY CLOUDY DAY 1ST DUE TO A WIDESPREAD
AND DEEP MARINE LAYER THAT WILL COVER ALL OF THE CSTS AND VLYS AND
THEN DUE TO CLOUDS STREAMING OFF OF RACHEL. SLO AND PORTIONS OF
SBA COUNTIES WILL PROBABLY BE PARTLY CLOUDY IN THE AFTERNOON AS
THE MID LEVEL CLOUDS WILL BE MORE FOCUSED OVER THE SOUTHERN
COUNTIES. THE COMBINATION OF 574 DAM HGTS , PLENTY OF CLOUDS, A
DEEP MARINE LAYER AND INCREASED ONSHORE FLOW WILL BRING DRAMATIC
COOLING TO THE ENTIRE AREA. LOOK FOR 6 TO 12 DEGREES OF COOLING
ALMOST EVERYWHERE (THE BEACHES OF THE CENTRAL COAST WILL HAVE
ALREADY COOLED DOWN TODAY AND FRIDAY). MOST COASTAL TEMPS WILL BE
IN THE LOWER TO MID 70S WITH A FEW UPPER 70S ACROSS THE INTERIOR
COASTAL SECTIONS OF LA COUNTY. THE VLYS WILL ONLY WARM INTO UPPER
70S AND LOWER 80S. MOST MAX TEMPS WILL END UP 3 TO 6 DEGREES BLO
NORMAL.
ENOUGH MOISTURE FROM RACHEL WILL MOVE UP INTO VTA AND LA COUNTIES
SATURDAY NIGHT TO WARRANT A SLIGHT CHC OF RAIN WITH POTENTIAL
RAINFALL AMOUNTS UP TO A TENTH OF AN INCH.
LONG TERM (SUN-WED)
08/243 AM.
A FAIRLY COMPLICATED WEATHER PATTERN OCCURS ON SUNDAY. A VERY
LARGE POS TILT TROF WILL DRAPE ITSELF ACROSS THE ENTIRE WEST
COAST. IT WILL NOT MOVE MUCH AT ALL, RATHER A COLD UPPER LOW WILL
PLUNGE TO SW DOWN THE TROF AXIS AND WILL SIT ATOP OF THE BAY AREA
BY LATE AFTERNOON. HGTS OVER SRN CA WILL FALL TO 565 DAM. ON TOP
(WELL ACTUALLY BELOW) ALL OF THIS TROPICAL STORM RACHEL WILL MOVE
INTO THE NORTHERN PORTION OF THE BAJA PENINSULA AND WILL SEND A
SURGE OF MOISTURE INTO THE TROF OVER SRN CA. A CHC OF RAIN WILL
DEVELOP OVER SBA/VTA AND ESP LA COUNTIES IN THE PREDAWN HOURS AND
WILL CONTINUE THROUGH THE EVENING. IN GENERAL A TENTH OF AN INCH
OF RAIN IS POSSIBLE FOR ANY GIVEN 6 HOUR PERIOD DURING THE DAY
WITH HEAVIER AMOUNTS ACROSS EASTERN LA COUNTY. RAINFALL FROM
MIDNIGHT TO MIDNIGHT LOOKS TO BE LITTLE OR NOTHING FOR SLO COUNTY,
A TRACE TO .20 FOR SBA COUNTY, A TENTH TO ABOUT A THIRD OF AN INCH
FOR VTA COUNTY AND A QUARTER TO A HALF INCH FOR MOST OF LA COUNTY
BUT .75 TO 1.5 INCHES OF RAIN IS POSSIBLE FOR THE EASTERN SAN
GABRIEL MTNS AND ITS COASTAL FOOTHILLS. THERE WILL ALSO BE 5-10%
CHANCE OF TSTMS OVER LA AND VTA COUNTIES WITH THE BEST CHC OVER LA
COUNTY. MAX TEMPS WILL RANGE FROM THE MID 60S TO MID 70S.
ON MONDAY THE UPPER LOW WILL MOVE INTO THE VCNTY OF SBA COUNTY
WITH 557 DAM HGTS. THE LOW WILL BRING CLOUDS AND CHC OF RAIN TO
THE ENTIRE 4 COUNTY FORECAST AREA FROM MIDNIGHT TO MIDNIGHT. SINCE
MOST OF THE MOISTURE WILL BE TO THE EAST OF THE AREA RAINFALL
TOTALS WILL NOT BE THAT GREAT MOST AREAS CAN EXPECT TO RECIEVE A
TENTH TO A QUARTER INCH OF RAINFALL. MAX TEMPS WILL FALL FURTHER
TO THE MID 60S TO LOWER 70S.
THERE IS SOME DISAGREEMENT ON HOW FAST THE UPPER LOW WILL MOVE OUT
OF THE AREA. ENOUGH SOLUTIONS KEEP THE UPPER LOW AROUND LONG
ENOUGH TO KEEP A 20 TO 30 PERCENT CHC OF RAIN IN THE FORECAST.
EVEN IF IT DOES RAIN THERE WILL NOT BE MUCH ADDITIONAL RAINFALL.
ASIDE FROM A SMALL CHC OF A MTN SHOWER WEDNESDAY SHOULD BE DRY AS
DRIER NW FLOW MOVES INTO AND OVER THE STATE. SUNNIER SKIES AND
RISING TEMPS WILL BRING 3 TO 6 DEGREES OF WARMING. EVEN WITH THE
WARMING MAX TEMPS WILL END UP ABOUT 6 DEGREES BLO NORMAL.
AVIATION
08/0942Z.
AT 0832Z AT KLAX, THE MARINE LAYER WAS 500 FEET DEEP. THE TOP OF
THE INVERSION WAS 1100 FEET WITH A TEMPERATURE OF 29 C.
HIGH CONFIDENCE IN CAVU CONDITIONS FOR KPRB, KBUR, KVNY, KWJF AND
KPMD.
MODERATE CONFIDENCE IN TAFS FOR KSBP, KSMX, KSBA, KOXR AND KCMA.
FLIGHT CAT CHANGES COULD BE OFF BY +/- 90 MINUTES. CIGS COULD BE
OFF BY +/- 200 FT. VIS MAY VARY FROM 1/4SM TO 1SM THROUGH 15Z.
LOW CONFIDENCE IN TAFS FOR KSMO, KLAX AND KLGB. THERE IS A 40%
CHANCE THAT CIG/VSBY RESTRICTIONS DO NOT DEVELOP. IF CIGS DO
ARRIVE THERE IS A 25 PERCENT CHC THAT CIGS WILL BE 004.
KLAX...LOW CONFIDENCE IN TAF. THERE IS A 30% CHANCE THAT CIG/VSBY
RESTRICTIONS DO NOT DEVELOP. IF CIG/VSBY RESTRICTIONS DO DEVELOP
THERE IS A 25 PERCENT CHC THAT CIGS WILL BE 004. NO SIGNIFICANT
EASTERLY WIND COMPONENT IS EXPECTED.
KBUR...HIGH CONFIDENCE IN CAVU TAF.
MARINE
08/241 AM.
RELATIVELY QUIET CONDITIONS EXPECTED ACROSS THE COASTAL WATERS
THROUGH FRIDAY. LOCALIZED SMALL CRAFT ADVISORY (SCA) GUSTS MAY
OCCUR EACH AFTERNOON AND EVENING BETWEEN POINT CONCEPTION AND SAN
NICOLAS ISLAND. NIGHT THROUGH MORNING DENSE FOG MAY AFFECT
PORTIONS OF THE COASTAL WATERS ADJACENT TO THE CENTRAL COAST AND
SOUTH TO SAN NICOLAS ISLAND.
THE BIGGEST CONCERN THIS WEEKEND WILL BE POTENTIAL IMPACTS FROM
THE INTERACTION BETWEEN A TROUGH COMING DOWN FROM THE NORTH AND
REMNANTS OF HURRICANE RACHEL FOCUSED ACROSS THE WATERS ADJACENT TO
LOS ANGELES AND ORANGE COUNTIES. THERE IS STILL A CONSIDERABLE
AMOUNT OF UNCERTAINTY IN REGARDING TO RACHEL'S FINAL TRACK WHICH
WILL DETERMINE THE EXACT DETAILS. THE MOST RECENT GUIDANCE HAS
SHIFTED THE TRACK WELL TO THE SOUTH OF THE COASTAL WATERS, WHICH
WOULD LIMIT IMPACTS. HOWEVER, STRONG SCA W-SW WINDS ARE STILL A
POSSIBILITY AS THE SYSTEM INTERACTS WITH THE TROUGH WITH A 20%
CHANCE OF GALES ESPECIALLY ACROSS THE INNER WATERS. PERIODS OF LIGHT
TO MODERATE RAIN, WITH A 10% CHANCE OF THUNDERSTORMS WILL BE
POSSIBLE ACROSS THE WATERS AS EARLY AS SATURDAY LASTING INTO AS
LATE AS TUESDAY EVENING (HIGHEST CONFIDENCE IN SUNDAY/MONDAY
TIMEFRAME). IN ADDITION, INCREASING WEST TO NORTHWEST WINDS AND
SEAS (10+ FOOT) ARE EXPECTED ACROSS THE OUTER WATERS THIS WEEKEND
INTO MONDAY.
PLEASE CONTINUE TO MONITOR THE FORECAST.
BEACHES
08/241 AM.
THE COASTAL FLOOD ADVISORIES HAVE BEEN EXTENDED INTO TUESDAY
AFTERNOON. SOUTHERLY SWELLS, INCLUDING FROM HURRICANE RACHEL,
WILL CONTINUE TO IMPACT THE LA/VTA COASTLINE. 180-190 DEGREES AT
12 SECONDS WILL POSE THE MOST RISK FROM MALIBU TO VENTURA THROUGH
FRIDAY. THE LONG BEACH AREA IS ALSO AT A RELATIVELY HIGHER RISK
DUE TO VULNERABILITIES FROM PREVIOUS COASTAL EVENTS. THE MORNING
AND EVENING HIGH TIDES WILL REMAIN SIMILAR IN HEIGHT AT 6.5-7.0 FT
THROUGH TONIGHT, WITH A 0.3 FT REDUCTION IN THE EVENING TIDES ON
FRIDAY.
MEANWHILE, HURRICANE RACHEL IS EXPECTED TO TURN NORTHEAST AND
WILL PICK UP IN MOVEMENT SPEED (WHILE WIND SPEED WEAKENS), LIKELY
MAKING LANDFALL ON SUNDAY SOMEWHERE IN NORTHERN BAJA CALIFORNIA OR
IN THE VICINITY OF THE MEXICO- UNITED STATES BORDER (AS A POST-
TROPICAL SYSTEM). THE EXACT TRACK WILL LIKELY BECOME MORE CLEAR
IN A DAY OR TWO AS THE SYSTEM TURNS TO THE NORTHEAST.
AS FOR IMPACTS, DEVIATIONS IN THE FINAL TRACK COULD INFLUENCE THE
MAGNITUDE OF IMPACTS FOR THE AREA. IF RACHEL TAKES A MORE
NORTHERLY TRACK, THE COMBINATION OF THE INCREASED WIND WAVE AND
LOWER SFC PRESSURE WOULD RESULT IN HIGHER TIDES, WHICH ARE ALREADY
EXPECTED TO INCREASE TO 7.0 TO 7.5 FEET (1 TO 1.5 FEET HIGHER THAN
ASTRONOMICAL TIDES) OVER THE WEEKEND.
AS OF NOW, THE MOST REASONABLE OUTCOME FOR LA/VENTURA AND
CATALINA ISLAND IS FLOODING OF SEA-WATER OVER BEACH ROADS AND
PATHS, AS WELL AS SIGNIFICANT BEACH EROSION, WITH ISOLATED DAMAGE
POSSIBLE. THE TIME WINDOW FOR MOST CONCERN IS SUNDAY, ESPECIALLY
DURING THE MORNING HIGH TIDE.
FOR THE CENTRAL COAST, HIGH SURF ADVISORIES WILL LIKELY BE NEEDED
SATURDAY THROUGH MONDAY. IN ADDITION, THERE IS A MODERATE RISK
FOR SOME BEACH EROSION AND ISOLATED, MINOR COASTAL FLOODING.
COASTAL FLOODING CONCERNS WILL CONTINUE INTO EARLY NEXT WEEK
REFER TO CFWLOX FOR MORE DETAILS AND PLEASE CONTINUE TO MONITOR
THE FORECAST FOR THE LATEST INFORMATION.
LOX WATCHES/WARNINGS/ADVISORIES
CA...EXTREME HEAT WARNING IN EFFECT UNTIL 8 PM PDT THIS EVENING
FOR ZONES 38-87-88-349>358-362-366>375-548-550. (SEE LAXNPWLOX).
COASTAL FLOOD ADVISORY IN EFFECT UNTIL 2 PM PDT TUESDAY FOR
ZONES 87-354-362-366. (SEE LAXCFWLOX).
HEAT ADVISORY IN EFFECT UNTIL 8 PM PDT THIS EVENING FOR ZONES
340>348. (SEE LAXNPWLOX).
PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT EARLY THIS
MORNING FOR ZONE 670. (SEE LAXMWWLOX).
PUBLIC...RORKE
AVIATION...RORKE
MARINE...BLACK/KL
BEACHES...BLACK/KL
SYNOPSIS...MW
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