064
FXUS66 KLOX 182044
AFDLOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
144 PM PDT THU SEP 18 2025
SYNOPSIS
18/907 AM.
THE REMNANTS OF TROPICAL STORM MARIO WILL CONTINUE TO AFFECT THE
REGION THROUGH FRIDAY, BRINGING HUMID CONDITIONS, SHOWERS, AND ISOLATED
THUNDERSTORMS. TEMPERATURES MAY BE COOLER DUE TO CLOUDY SKIES AND
SHOWERS, BUT AREAS THAT RECEIVE ANY SUNSHINE DURING THE DAY WILL
HEAT UP RAPIDLY.
SHORT TERM (TDY-SUN)
18/141 PM.
SYNOPTICALLY, THE AREA IS UNDER AN UPPER-LEVEL TROUGH THAT EXTENDS
THE LENGTH OF CALIFORNIA. MOISTURE REMNANTS OF TROPICAL STORM
MARIO ARE FUELING WIDESPREAD SHOWERS IN SOCAL. WHILE THE MOISTURE
WILL REMAIN IN THE AREA FOR A COUPLE OF DAYS, A RIDGE WILL BEGIN
TO PUSH IN FROM THE SOUTH LATER FRIDAY AND THROUGH THE WEEKEND.
ON MONDAY A LOW PRESSURE AREA THAT WAS HOVERING TO THE WEST WILL
MOVE OVER SOCAL FOR A RETURNING CHANGE OF RAIN MONDAY THROUGH
WEDNESDAY. BY NEXT THURSDAY THE RIDGE BEGINS TO REBUILD.
SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO MOVE NORTH ACROSS
SOUTHERN CALIFORNIA AS MOISTURE AND INSTABILITY WITH THE REMNANTS
OF FORMER TROPICAL STORM MARIO TRACKS NORTH. A VERY MOIST AIR
MASS IS IN PLACE ALREADY WITH PRECIPITABLE WATER VALUES
APPROACHING 2 INCHES THIS MORNING, OR ABOUT 200 TO 250 PERCENT
NORMAL. MOST AREAS ACROSS THE SOUTHLAND HAVE SEEN LIGHT AMOUNTS
TODAY WITH SOME ISOLATED HEAVIER CELLS OCCASIONALLY. RAINFALL
AMOUNTS ARE GENERALLY A TENTH OF AN INCH OR LESS WITH LOCAL
AMOUNTS UP TO 0.25 INCH.
EASTERN LA COUNTY, ESPECIALLY IN THE MOUNTAINS, WILL BE A FOCUS
FOR LIGHTNING STRIKES AS DAYTIME HEATING WILL INCREASE INSTABILITY
WITH THE VERY MOIST AIR MASS IN THE PLACE AND THE THREAT OF
THUNDERSTORMS DEVELOPING, HEAVY RAINFALL IS POSSIBLE WITH ANY
THUNDERSTORMS IN ADDITION TO DANGEROUS LIGHTNING, AND GUSTY AND
ERRATIC WINDS. A FLOOD WATCH REMAINS IN EFFECT THROUGH EARLY
FRIDAY MORNING, MOSTLY FOR THE MOUNTAINS AND ANTELOPE VALLEY.
SHOWERS WILL CONTINUE ON AND OFF THROUGH LATE TONIGHT AND INTO
FRIDAY, THEN CONVECTIVE ACTIVITY SHOULD BECOME CONFINED TO THE THE
HIGHER TERRAIN. WITH MORE SUNLIGHT AND DAYTIME HEATING, BRIEF
HEAVY RAINFALL CANNOT BE RULED OUT AGAIN FRIDAY AFTERNOON AS LESS
CLOUDINESS COULD PROMOTE A MORE UNSTABLE LAPSE RATE TO DEVELOP.
A SLIGHTLY WARMER AND DRIER PATTERN SHOULD DEVELOP SATURDAY AND
SUNDAY WITH DOWNTOWN LA GETTING INTO THE LOW 80S.
LONG TERM (MON-THU)
18/143 PM.
THERE IS A MODERATE CHANCE THAT ANOTHER MOISTURE SURGE FROM THE
SOUTH COULD BRING SOME SHOWERS AND THUNDERSTORMS WITH LOCALLY
HEAVY RAIN BETWEEN MONDAY AND TUESDAY. AN UPPER LOW MEANDERING
DOWN THE WEST COAST COULD INGEST SOME SUBTROPICAL MOISTURE WITH A
SHORTWAVE TROUGH OFF CABO SAN LUCAS AND BRING IT NORTHWARD. THIS
COULD HAPPEN AS EARLY AS SUNDAY AFTERNOON, BUT MORE LIKELY NOT
UNTIL MONDAY AFTERNOON. CONFIDENCE IS REMAINS LOW AT THIS POINT,
BUT THERE ARE LOW CHANCES OF SHOWERS IN THE FORECAST FOR EARLY
NEXT WEEK.
THE LATTER PART OF NEXT WEEK LOOKS WARM AND DRY. THERE IS A
MODERATE CHANCE THAT A HEATWAVE COULD DEVELOP FOR THE LATTER HALF
OF NEXT WEEK, BUT THE SPREAD ACROSS THE MODEL SOLUTION IS PRETTY
WIDE AT THIS POINT.
AVIATION
18/1627Z.
AT 1615Z AT KLAX, THERE WAS NO MARINE LAYER. HOWEVER, THERE WAS A
MOIST LAYER UP TO 10000 FEET.
OVERALL...LOW TO MODERATE CONFIDENCE IN 18Z TAF PACKAGE. THROUGH
THIS EVENING, VFR CONDITIONS ARE EXPECTED AT ALL SITES ALTHOUGH
BRIEF PERIODS OF MVFR CONDITIONS WILL BE POSSIBLE WITH ANY SHOWERS
OR THUNDERSTORMS.
FOR TONIGHT/FRIDAY MORNING, LOW CONFIDENCE IN RETURN OF MVFR
CONDITIONS TO COASTAL/VALLEY SITES AS WELL AS LOW CONFIDENCE IN
TIMING OF POTENTIAL RETURN OF CIG/VSBY RESTRICTIONS.
KLAX...OVERALL, MODERATE CONFIDENCE IN 18Z TAF. THERE IS A 20-30%
CHANCE OF BRIEF MVFR CONDITIONS THROUGH 03Z WITH ANY SHOWER
ACTIVITY. THERE IS A 20% CHANCE OF TSTMS 18Z-03Z. FOR TONIGHT,
THERE IS A 50% CHANCE THAT CIG/VSBY RESTRICTIONS DO NOT DEVELOP.
NO SIGNIFICANT EASTERLY WIND COMPONENT IS EXPECTED.
KBUR...OVERALL, MODERATE CONFIDENCE IN 18Z TAF. THERE IS A 20-30%
CHANCE OF BRIEF MVFR CONDITIONS THROUGH 03Z WITH ANY SHOWER
ACTIVITY. THERE IS A 20% CHANCE OF TSTMS 18Z-03Z. FOR TONIGHT,
THERE IS A 50% CHANCE THAT CIG/VSBY RESTRICTIONS DO NOT DEVELOP.
MARINE
18/113 PM.
FOR THE OUTER WATERS, MODERATE TO HIGH CONFIDENCE IN CURRENT
FORECAST. TODAY THROUGH FRIDAY, HIGH CONFIDENCE IN WINDS AND SEAS
REMAINING BELOW SMALL CRAFT ADVISORY (SCA) LEVELS. FOR SATURDAY
THROUGH MONDAY, THERE IS A 50-70% CHANCE OF SCA LEVEL WINDS.
FOR THE INNER WATERS NORTH OF POINT SAL, MODERATE TO HIGH
CONFIDENCE IN CURRENT FORECAST. TODAY THROUGH SATURDAY, HIGH
CONFIDENCE IN WINDS AND SEAS REMAINING BELOW SCA LEVELS. FOR
SUNDAY AND MONDAY, THERE IS A 30-40% CHANCE OF SCA LEVEL WINDS IN
THE AFTERNOON AND EVENING HOURS.
FOR THE INNER WATERS SOUTH OF POINT CONCEPTION, MODERATE TO HIGH
CONFIDENCE IN CURRENT FORECAST. FOR THE WESTERN HALF OF THE SANTA
BARBARA CHANNEL, THERE IS A 40-50% CHANCE OF SCA LEVEL WINDS IN
THE LATE AFTERNOON AND EVENING HOURS SATURDAY THROUGH MONDAY.
OTHERWISE ACROSS THE SOUTHERN INNER WATERS, HIGH CONFIDENCE IN
WINDS AND SEAS REMAINING BELOW SCA LEVELS THROUGH MONDAY.
THE REMNANTS OF FORMER TROPICAL STORM MARIO WILL AFFECT THE
SOUTHERN CALIFORNIA COASTAL WATERS THROUGH FRIDAY. SHOWERS WITH
ISOLATED TO SCATTERED THUNDERSTORMS CAN BE EXPECTED WITH THE
HIGHEST CHANCES OF IMPACTS THROUGH TONIGHT. ANY THUNDERSTORMS
THAT DEVELOP WILL BE CAPABLE OF GUSTY AND ERRATIC WINDS, LOCALLY
ROUGH SEAS, FREQUENT AND DANGEROUS LIGHTNING, AND BRIEF HEAVY
RAIN. ADDITIONALLY, WATERSPOUTS CANNOT BE RULED OUT ENTIRELY.
PLEASE MONITOR THE FORECAST IF YOU HAVE ANY PLANS ON GOING OUT ON
THE WATER THIS WEEK.
LOX WATCHES/WARNINGS/ADVISORIES
CA...FLOOD WATCH IN EFFECT THROUGH LATE TONIGHT FOR ZONES 377>383. (SEE LAXFFALOX).
PZ...NONE.
PUBLIC...HALL/JLD
AVIATION...RAT
MARINE...RAT
SYNOPSIS...JLD
WEATHER.GOV/LOSANGELES
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