096
FXUS66 KLOX 171013
AFDLOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
313 AM PDT WED SEP 17 2025
SYNOPSIS
16/146 PM.
IT WILL BE WARM AND MUGGY THROUGH FRIDAY AS REMNANTS OF TROPICAL
STORM MARIO MOVE INTO THE AREA. TEMPERATURES WILL COOL THROUGH THE
PERIOD BUT HUMIDITIES WILL BE MUCH HIGHER THAN NORMAL. RAIN AND
THUNDERSTORM CHANCES WILL BEGIN WEDNESDAY NIGHT AND CONTINUE INTO
AT LEAST EARLY FRIDAY. OVER THE WEEKEND INTO EARLY NEXT WEEK THERE
IS SLIGHT CHANCE OF SHOWERS AS ADDITIONAL MOISTURE FROM THE SOUTH
ARRIVES. TEMPERATURES WILL BE NEAR NORMAL AND THE MUGGY WEATHER
WILL CONTINUE INTO EARLY NEXT WEEK.
SHORT TERM (TDY-FRI)
17/300 AM.
FOR THE NEXT THREE DAYS SRN CA IS GOING TO FEEL LIKE FLORIDA WEST.
MOISTURE FROM THE REMNANTS OF TROPICAL STORM MARIO IS MOVING INTO
THE FORECAST AREA. THERE IS ALREADY ONE BAND OF TSTMS IN THE OUTER
WATERS TO THE SW OF PT CONCEPTION. MOISTURE WILL CONTINUE TO
INCREASE UNTIL IT REACHES ITS PEAK (AROUND 1.9") IN THE LATE
MORNING ON THURSDAY. THE CHC OR SHOWERS WILL INCREASE THROUGH THE
DAY TODAY BUT MOST OF THE SHOWER AND TSTM ACTIVITY WILL REMAIN
OVER THE WATERS. THE CHC OF SHOWERS WILL INCREASE FROM ABOUT 20
PERCENT EARLY THIS EVENING TO ABOUT 40 PERCENT BY DAWN ON
THURSDAY. SHOWERS MAY BE ACCOMPANIED BY TSTMS. SHOWERS ARE LIKELY
(60 TO 70 PERCENT CHC) THROUGHOUT THE DAY ON THURSDAY AS THE
MAXIMUM MOISTURE AND INSTABILITY AND MOISTURE PASSES OVER THE
AREA. ALMOST ALL AREAS CAN EXPECT RAIN AT SOME POINT DURING THE
DAY. MOST PEOPLE WILL AT LEAST HEAR THUNDER, IF NOT EXPERIENCE A
TSTM AS WELL. THIS WILL NOT BE A CONTINUOUS RAIN EVENT BUT RATHER
A DAY WITH PERIODS OF SHOWERS/TSTMS AND PERIODS OF MUGGY WEATHER
WITH NO RAIN. THE CHC OF SHOWERS/TSTMS WILL THEN SLOWLY DIMINISH
FROM THURSDAY EVENING THROUGH EARLY FRIDAY EVENING WHEN THE THREAT
OF SHOWERS SHOULD END.
RAINFALL AMOUNTS WILL BE THE HARDEST PART OF THIS FORECAST.
AMOUNTS WILL BE HIGHLY VARIABLE DUE TO THE SHOWERY NATURE OF THIS
SYSTEM. THE CURRENT FORECAST CALLS FOR MOST OF LA AND VTA COUNTIES
TO RECEIVE A HALF INCH OF RAIN WITH LOCAL THREE QUARTER INCH
AMOUNTS. SOME MTN AREAS COULD SEE UPWARDS OF AN INCH. AREAS NORTH
OF POINT CONCEPTION ARE FORECAST TO GET ABOUT HALF THESE AMOUNTS,
BUT IF THE MAIN MOISTURE AXIS TRACKS A LITTLE TO THE WEST MORE
RAIN WILL FALL. THESE NUMBERS ARE GENERAL NUMBERS AND THERE WILL
VERY LIKELY BE OUTLIERS SOME AREA MAY ONLY SEE A TENTH OF AN INCH
BUT OTHER AREAS COULD SEE UP TO 2 INCHES OF RAIN IF A STRONG
SHOWER OR TSTM MOVES OVER THE AREA. RAINFALL RATES UNDER THE
HEAVIER CELLS WILL BE NEAR A HALF INCH PER HOUR, BUT WITH PWATS
APPROACHING 2 INCHES CANNOT RULE OUT THE POSSIBILITY OF 1 INCH
PER HOUR RATES.
A FLOOD WATCH WILL BE CONSIDERED THIS MORNING AFTER CONSULTING THE
12Z MDLS AND COORDINATING WITH SURROUNDING OFFICES.
THE INCREASING CLOUDS WILL KNOCK A FEW DEGREES OFF OF MOST TEMPS
TODAY (THE CENTRAL COAST WILL ACTUALLY WARM UP SOME WITH SOME
OFFSHORE FLOW FROM THE EAST). THE INCREASE IN HUMIDITY WILL,
HOWEVER, NEGATE ANY AFFECTS OF THE TEMPERATURE DECREASE. THE
MASSIVE AMOUNT OF CLOUDS AND PERIODS OF RAIN ON THURSDAY WILL
BRING 5 TO 10 LOCALLY 15 DEGREES OF COOLING TO AREAS AWAY FROM THE
COAST DROPPING ALMOST ALL TEMPS INTO THE 80S. STILL WITH THE
HUMIDITY IT WILL FEEL VERY STICKY AND TROPICAL. NOT MUCH CHANGE
IN TEMPS ON FRIDAY IT WILL STILL BE HUMID BUT NOT QUITE AS MUCH AS
ON THURSDAY.
LONG TERM (SAT-TUE)
17/1231 AM.
THE WEEKEND SHOULD BE DRY BUT THERE IS A SLIGHT CHC (20 PERCENT)
OF SOME AFTERNOON CONVECTION OVER THE TALLER PEAKS OF THE VTA AND
LA MTNS. THE ATMOSPHERE WILL SLOWLY DRY BUT BOTH DAYS WILL FEEL
PRETTY MUGGY WITH HIGHER THAN NORMAL HUMIDITIES. AN UPPER HIGH
WILL PUSH INTO SRN CA FROM THE SOUTH AND HGTS WILL RISE TO 588
DAM. LOOK FOR TWO DAYS WITH 2 TO 4 DEGREES OF WARMING, WHICH WILL
BRING MAX TEMPS UP TO NEAR NORMAL BY SUNDAY.
THERE IS QUITE A BIT OF UNCERTAINTY WITH THE FORECAST FOR EARLY
NEXT WEEK. THE EC AND MOST OF ITS ENSEMBLES FAVOR A VERY WARM
PATTERN WITH A STRONG UPPER RIDGE OVER THE AREA - THIS SOLUTION
WOULD BRING TRIPLE DIGIT TEMPS BACK TO THE VLYS. THE GFS IS COOLER
WITH A LITTLE TROFFIER PATTERN. THERE DOES SEEM TO BE PRETTY GOOD
CONSENSUS THAT THERE WILL BE SOME WARMING ON MONDAY.
TUESDAY'S FORECAST FAVORS A TROFFIER COOLER PATTERN WITH A LITTLE
MORE MARINE LAYER.
AVIATION
17/1012Z.
AROUND 07Z, THE MARINE LAYER DEPTH WAS AROUND 800 FEET DEEP AT
KLAX. THE TOP OF THE INVERSION WAS AROUND 1600 FEET WITH A
TEMPERATURE OF NEAR 28 DEGREES CELSIUS.
LOW-TO-MODERATE CONFIDENCE IN THE CURRENT FORECAST. THERE IS A
MODERATE-TO-HIGH CHANCE OF LIFR TO LIFR CONDITIONS AT CENTRAL
COAST TERMINALS THROUGH 16Z, AND AGAIN AFTER 02Z THURSDAY. THERE
IS A 15-30 PERCENT CHANCE OF THUNDERSTORMS AFTER 00Z THURSDAY,
HIGHEST AT LOS ANGELES COUNTY TERMINALS. ANY SHOWERS AND
THUNDERSTORMS THAT MOVE OVER OR IN THE VICINITY OF TERMINALS MAY
HAVE BRIEF HEAVY RAINFALL WITH IFR TO MVFR CONDITIONS AND GUSTY
AND ERRATIC WINDS.
KLAX...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. THERE IS A
20 PERCENT CHANCE OF THUNDERSTORMS AFTER 00Z WITH THE HIGHEST
CHANCE OF SHOWERS AFTER 04Z. ANY EASTERLY WINDS SHOULD REMAIN LESS
THAN 7 KNOTS, BUT THERE IS A 5 PERCENT CHANCE OF EAST WINDS
BETWEEN 7 AND 10 KNOTS AFTER 10Z THURSDAY.
KBUR...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. THERE IS A
20 PERCENT CHANCE OF THUNDERSTORMS AFTER 00Z WITH THE HIGHEST
CHANCE OF SHOWERS AFTER 05Z.
MARINE
17/312 AM.
LOW TO MODERATE CONFIDENCE IN THE CURRENT FORECAST THROUGH FRIDAY,
THEN MODERATE CONFIDENCE THEREAFTER. HIGHER CONFIDENCE IN SEAS
RELATIVE TO WINDS THROUGH FRIDAY. LOWER CONFIDENCE IN THE COASTAL
WATERS IMPACTS THROUGH FRIDAY.
THE REMNANTS OF FORMER TROPICAL STORM MARIO WILL AFFECT SOUTHERN
CALIFORNIA COASTAL WATERS THROUGH FRIDAY. SHOWERS ARE ALREADY
STREAMING INTO THE COASTAL WATERS EARLY THIS MORNING WITH ISOLATED
THUNDERSTORMS APPROACHING THE WESTERN PORTIONS OF THE OUTER
WATERS. PERIODS OF SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE
WATERS THROUGH FRIDAY WITH THE HIGHEST CHANCE FOR IMPACTS BETWEEN
LATE TONIGHT AND THURSDAY NIGHT. ANY THUNDERSTORMS THAT DEVELOP
WILL BE CAPABLE OF GUSTY AND ERRATIC WINDS, LOCALLY ROUGH SEAS,
FREQUENT AND DANGEROUS CLOUD-TO-OCEAN LIGHTNING, BRIEF HEAVY
RAINFALL. WATERSPOUTS CANNOT BE RULED OUT ENTIRELY. AS WELL AS
STRONG AND ERRATIC WINDS. PLEASE MONITOR THE FORECAST IF YOU HAVE
ANY PLANS ON GOING OUT ON THE WATER THIS WEEK.
MARGINAL SMALL CRAFT ADVISORY (SCA) WINDS ARE POSSIBLE ACROSS THE
WATERS SOUTH AND EAST OF POINT CONCEPTION AND INTO THE SOUTHERN
CALIFORNIA BIGHT THIS AFTERNOON AND EVENING. WINDS AND SEAS
SHOULD REMAIN BELOW SCA LEVELS BETWEEN FRIDAY AND SATURDAY, BUT
THERE IS A MODERATE CHANCE FOR SCA WINDS IN THE TYPICAL WINDY
SPOTS FROM POINT CONCEPTION SOUTH TO SAN NICOLAS ISLAND EACH
AFTERNOON AND EVENING OVER THE WEEKEND AND INTO MONDAY AFTERNOON
AND EVENING.
LOX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY IN EFFECT FROM 2 PM THIS AFTERNOON TO 9
PM PDT THIS EVENING FOR ZONES 650-655-673-676. (SEE LAXMWWLOX).
PUBLIC...RORKE
AVIATION...HALL
MARINE...HALL
SYNOPSIS...MW
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
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