144
FXUS66 KLOX 090914
AFDLOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
214 AM PDT FRI OCT 9 2026
SYNOPSIS
08/801 PM.
TEMPERATURES ACROSS THE REGION ARE EXPECTED TO TREND COOLER
FRIDAY INTO SUNDAY AND THERE WILL BE AN INCREASING CHANCE OF
SHOWERS AND THUNDERSTORMS DUE TO MOISTURE FROM HURRICANE RACHEL.
THESE SHOWERS COULD PERSIST INTO TUESDAY, WITH ANOTHER WARMING
TREND POSSIBLE WEDNESDAY THROUGH FRIDAY.
SHORT TERM (TDY-SUN)
09/213 AM.
OVERALL, 00Z MODELS IN GOOD SYNOPTIC AGREEMENT THROUGH THE SHORT
TERM PERIOD. MAIN FEATURE OF NOTE WILL BE AN UPPER LOW THAT DROPS
SOUTHWARD OFF THE CA COAST TODAY/SATURDAY THEN MOVE INLAND ACROSS
FAR SOUTHERN CALIFORNIA ON SUNDAY. AS THIS LOW DROPS SOUTHWARD, IT
WILL INTERACT WITH MOISTURE FROM TROPICAL STORM RACHEL LATE
SATURDAY AND SUNDAY.
MAIN CONCERN IN THE SHORT TERM WILL BE THE CHANCES OF RAINFALL
ACROSS THE AREA AS THE UPPER LOW SUCKS UP MOISTURE FROM RACHEL. AT
THIS TIME, NO MAJOR CHANGES FROM PREVIOUS THINKING. THE BEST
MOISTURE WILL REMAIN SOUTH OF THE CWA, BUT WE WILL STILL GET SOME
DECENT RAIN. RAIN WILL BEGIN OVER LA COUNTY LATE SATURDAY,
SPREADING ACROSS ALL AREAS SATURDAY NIGHT/SUNDAY MORNING THEN THE
RAIN CHANCES WILL SHIFT EASTWARD SUNDAY AFTERNOON/EVENING. RAIN
TOTALS THROUGH SUNDAY EVENING LOOK TO GENERALLY RANGE FROM
0.10-0.50 INCHES ACROSS VENTURA/LA COUNTIES WITH UP TO AROUND
1.00 INCH ACROSS THE SAN GABRIEL MOUNTAINS. FOR SANTA BARBARA AND
SAN LUIS OBISPO COUNTIES, RAIN CHANCES ARE MUCH LESS AND ANY
MEASURABLE RAINFALL SHOULD ONLY AMOUNT TO A FEW HUNDREDTHS OF AN
INCH. LOOKING AT THE LATEST ENSEMBLE SOLUTIONS, THESE QPF NUMBERS
LOOK ON TRACK. OF COURSE ANY CHANGE IN THE TRACK OF RACHEL COULD
RESULT IN CHANGES TO THESE QPF NUMBERS.
AS FOR THUNDERSTORM CHANCES, CURRENT CONVECTIVE PARAMETERS DO NOT
LOOK TOO IMPRESSIVE FOR THE AREA. HOWEVER, GIVEN THE COMPLEXITY OF
THE INTERACTION BETWEEN THE UPPER LOW AND RACHEL, IT SEEMS PRUDENT
TO KEEP A LOW CHANCE (5-10%) OF THUNDERSTORMS ON SUNDAY.
PROBABILITIES ARE NOT HIGH ENOUGH TO MENTION IN THE OFFICIAL
FORECAST, BUT SHOULD BE KEPT IN THE BACK OF EVERYONE'S MIND.
OTHER THAN THE RAIN ISSUES FOR THE AREA, THE FORECAST IS PRETTY
STRAIGHTFORWARD. ONSHORE FLOW WILL CONTINUE ACROSS THE AREA
THROUGH SUNDAY. WITH LOWERING H5 HEIGHTS, THIS WILL ALLOW FOR THE
MARINE LAYER TO BECOME DEEPER AND MORE WIDESPREAD THROUGH THE
WEEKEND. ADDITIONALLY, THERE WILL BE GOOD COOLING TREND EACH DAY,
GIVING THE AREA A REFRESHING CHANGE FROM THE HEAT EARLIER THIS
WEEK. THE INCREASING ONSHORE FLOW WILL GENERATE GUSTY
SOUTHWESTERLY WINDS ACROSS INTERIOR SECTIONS WITH A LOW CHANCE OF
ADVISORY-LEVEL GUSTS ON SUNDAY ACROSS THE DESERT FOOTHILLS.
LONG TERM (MON-THU)
09/213 AM.
FOR THE EXTENDED PERIOD, 00Z MODELS EXHIBIT SOME NOTICEABLE
DISAGREEMENT, LEADING TO RELATIVELY LOW CONFIDENCE IN THE
EXTENDED FORECAST. THE GFS, AND ITS ENSEMBLES, DROP AN UPPER LOW
ALONG THE CA COAST AND OVER THE AREA ON MONDAY THEN MOVE IT
EASTWARD OVER THE AREA AND INTO THE GREAT BASIN ON TUESDAY AND
WEDNESDAY. CONVERSELY, THE ECMWF, AND ITS ENSEMBLES, DROP THE LOW
OVER THE GREAT BASIN MONDAY AND TUESDAY, BEFORE EJECTING IT
EASTWARD ON WEDNESDAY AND THURSDAY.
FORECAST-WISE, EITHER MODEL SOLUTION WILL GENERATE A THREAT OF
SHOWERS ACROSS ALL AREAS MONDAY AND TUESDAY. GIVEN THE UNCERTAINTY
OF THE PATTERN, FORECAST TAKES A MIDDLE GROUND. RAINFALL TOTALS ON
MONDAY AND TUESDAY ARE FORECAST TO RANGE BETWEEN 0.10 AND 0.25
INCHES FOR MOST AREAS WITH UP TO AROUND 0.50 INCHES IN THE
MOUNTAINS. IF THE GFS SOLUTIONS VERIFIES, THE RAINFALL TOTALS
WOULD BE ON THE HIGHER SIDE OF THAT RANGE. AS FOR ANY THUNDERSTORM
THREAT, THE GFS TRACK OF THE UPPER LOW COULD GIVE SOME MENTIONABLE
CHANCE OF THUNDERSTORMS WHILE THE ECMWF SOLUTION WOULD NOT. SO,
WILL ANY CHANCES OF THUNDERSTORMS UNDER 10% AT THIS TIME AND SEE
HOW THINGS DEVELOP.
FOR WEDNESDAY AND THURSDAY, BOTH MODELS INDICATE INCREASING
OFFSHORE PRESSURE GRADIENTS. THE ECWMF IS STRONGER WITH THE
FORECAST GRADIENTS, INDICATING THE POTENTIAL FOR WEAK (TO POSSIBLY
MODERATE) SANTA ANA WINDS. THE GFS, WITH ITS WEAKER GRADIENTS,
WOULD INDICATE A WEAK SANTA ANA AT WORST. EITHER WAY, WITH RISING
H5 HEIGHTS AND SOME AMOUNT OF OFFSHORE FLOW, TEMPERATURES WILL BE
ON THE UPSWING WEDNESDAY AND THURSDAY.
AVIATION
09/0410Z.
AT 0400Z AT KLAX, THE MARINE LAYER WAS 800 FEET DEEP. THE TOP OF
THE INVERSION WAS 3500 FEET WITH A TEMPERATURE OF 27 DEGREES
CELSIUS.
FOR 06Z TAF PACKAGE, HIGH CONFIDENCE IN KPRB, KBUR, KVNY, KPMD
AND KWJF AS CAVU CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
FOR COASTAL SITES, MODERATE CONFIDENCE IN 06Z TAFS AS TIMING OF
FLIGHT CATEGORY CHANGES COULD BE +/- 3 HOURS OF CURRENT FORECASTS
AND POSSIBLY OFF BY ONE FLIGHT CATEGORY.
KLAX...MODERATE CONFIDENCE IN 06Z TAF. TIMING OF FLIGHT CATEGORY
CHANGES COULD BE +/- 3 HOURS OF CURRENT FORECASTS. THERE IS A
30-4% CHANCE OF LIFR CONDITIONS 08Z-14Z. NO SIGNIFICANT EASTERLY
WIND COMPONENT IS EXPECTED.
KBUR...HIGH CONFIDENCE IN 06Z TAF AS CAVU CONDITIONS ARE EXPECTED
THROUGH THE PERIOD.
MARINE
09/213 AM.
FOR THE OUTER WATERS, MODERATE TO HIGH CONFIDENCE IN CURRENT
FORECAST. TODAY THROUGH SATURDAY MORNING, HIGH CONFIDENCE IN WINDS
AND SEAS REMAINING BELOW SMALL CRAFT ADVISORY (SCA) LEVELS. FROM
SATURDAY AFTERNOON THROUGH MONDAY, HIGH CONFIDENCE IN A
COMBINATION OF SCA LEVEL WINDS AND SEAS. ON TUESDAY, THERE IS A
50% CHANCE OF SCA LEVEL WINDS AROUND POINT CONCEPTION WITH WINDS
REMAINING BELOW SCA LEVELS ELSEWHERE.
FOR THE INNER WATERS NORTH OF POINT SAL, HIGH CONFIDENCE IN
CURRENT FORECAST. TODAY THROUGH SATURDAY MORNING, WINDS AND SEAS
ARE EXPECTED TO REMAIN BELOW SCA LEVELS. FROM SATURDAY AFTERNOON
THROUGH TUESDAY, SCA LEVEL WINDS ARE EXPECTED (MAINLY IN THE
AFTERNOON AND EVENING HOURS) WITH SEAS APPROACHING SCA LEVELS ON
SUNDAY AND MONDAY.
FOR THE INNER WATERS SOUTH OF POINT CONCEPTION, MODERATE TO HIGH
CONFIDENCE IN CURRENT FORECAST. TODAY THROUGH SATURDAY, HIGH
CONFIDENCE IN WINDS AND SEAS REMAINING BELOW SCA LEVELS. FOR
SUNDAY, THERE IS A 60-80% CHANCE OF SCA LEVEL WINDS. FOR MONDAY
THROUGH TUESDAY, HIGH CONFIDENCE IN WINDS AND SEAS REMAINING BELOW
SCA LEVELS EXCEPT FOR A 50% CHANCE OF SCA LEVEL WINDS ON TUESDAY
ACROSS THE WESTERN HALF OF THE SANTA BARBARA CHANNEL.
WIDESPREAD LIGHT TO MODERATE RAINFALL IS LIKELY SATURDAY EVENING
THROUGH TUESDAY, WITH HIGHEST CONFIDENCE FOR SUNDAY-MONDAY. THERE
IS A 10% CHANCE OF THUNDERSTORMS DURING THE SAME TIME FRAME.
WHILE SHOWERS OR THUNDERSTORMS ARE POSSIBLE ANYWHERE, HIGHEST
CHANCES EXIST SOUTH OF POINT CONCEPTION.
BEACHES
09/213 AM.
A COASTAL FLOOD ADVISORY IS IN EFFECT THROUGH TUESDAY AFTERNOON
FOR LOS ANGELES AND VENTURA COUNTIES, WHILE A BEACH HAZARDS
STATEMENT (BHS) IS IN EFFECT FOR THE SANTA BARBARA SOUTH COAST AND
THE CENTRAL COAST.
A VERY COMPLEX SERIES OF SWELLS FROM THE SOUTH, WEST, AND
NORTHWEST WILL IMPACT OUR COASTLINES INTO AT LEAST EARLY NEXT
WEEK. ENERGY FROM TROPICAL STORM RACHEL, SOUTHERN HEMISPHERE
SWELLS, NORTHWEST SWELLS, AND LOCAL WIND SWELLS WILL ADD UP WITH
EACH OTHER TO PRODUCE ELEVATED SURF AND DANGEROUS RIP CURRENTS AT
TIMES. EXTREMELY HIGH TIDES WILL BE COMMON EACH MORNING, PEAKING
BETWEEN 6.8 TO 7.6 FEET MLLW, HIGHEST FURTHER SOUTH. ADDITIONALLY
SECONDARY HIGH TIDES WILL PEAK EACH EVENING, LIKELY MOST IMPACTFUL
THROUGH THE WEEKEND WITH TIDES REACHING 5.5 TO 6.5 FEET MLLW.
WHILE EACH DAY UNDER THE COASTAL FLOOD ADVISORIES OR BHS SHOULD
SEE FAIRLY SIMILAR IMPACTS, SUNDAY WILL LIKELY SEE ELEVATED
IMPACTS. RAPIDLY INCREASING WIND SPEEDS WILL LIKELY ADD TO THE
COASTAL FLOODING POTENTIAL, CREATING A WIND SWELL AS WELL AS
ELEVATING TIDES SLIGHTLY. ADDITIONALLY, IF RACHEL'S TRACK
DEVIATES A BIT MORE TO THE NORTH THAT WOULD RESULT IN LOWER
MEAN SEA LEVEL PRESSURE CONTRIBUTING TO EVEN HIGHER WATER LEVELS.
IF ALL THESE INGREDIENTS OVERLAP ON SUNDAY, A MORE SIGNIFICANT
COASTAL FLOODING EVENT WILL BE LIKELY. THIS IS A VERY NARROW
WINDOW, BUT THERE IS A LOW CHANCE FOR A TARGETED COASTAL FLOOD
WARNING TO BE ISSUED IN SOUTHERN LOS ANGELES COUNTY IF ALL FACTORS
LINE UP.
AS THIS IS A COMPLEX AND EVOLVING SITUATION, PLEASE CONTINUE TO
MONITOR THE FORECAST.
LOX WATCHES/WARNINGS/ADVISORIES
CA...COASTAL FLOOD ADVISORY IN EFFECT UNTIL 2 PM PDT TUESDAY FOR
ZONES 87-354-362-366. (SEE LAXCFWLOX).
BEACH HAZARDS STATEMENT IN EFFECT FROM SATURDAY MORNING
THROUGH MONDAY AFTERNOON FOR ZONES 340-346-349-350. (SEE LAXCFWLOX).
PZ...NONE.
PUBLIC...THOMPSON
AVIATION...RAT
MARINE...RAT
BEACHES...LEWIS/BLACK/RAT
SYNOPSIS...MW/CILIBERTI
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
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