909
FXUS66 KLOX 190319
AFDLOX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
819 PM PDT SUN OCT 18 2026
SYNOPSIS
18/722 PM.
A SIGNIFICANT COOL DOWN IS EXPECTED ACROSS SOUTHWEST CALIFORNIA
THROUGH THE MIDDLE PART OF THE WEEK. WIDESPREAD RAIN IS LIKELY
TUESDAY NIGHT THROUGH THURSDAY WITH A SLIGHT CHANCE OF
THUNDERSTORMS.
SHORT TERM (SUN-WED)
18/809 PM.
***UPDATE***
THE COOLING TREND KICKED OFF TODAY FOR MOST OF THE AREA DUE TO
MORNING OFFSHORE FLOW WEAKENING COMPARED TO THE PREVIOUS DAYS,
AND THE ONSHORE TRENDS INCREASED. A FEW AREAS SAW A TINY BIT OF
WARMING COMPARED TO YESTERDAY DUE TO SOME LINGERING OFFSHORE WIND
ACROSS THE INTERIOR SLO AND I-5 CORRIDOR. OTHERWISE, MOST AREAS
DROPPED AS MUCH AS 8 DEGREES COMPARED TO YESTERDAY. OVERALL, HIGHS
WERE IN THE HIGH 70S TO HIGH 80S, WITH A FEW LOCATIONS JUST
BARELY MAKING IT INTO THE LOW 90S.
CURRENT SATELLITE IMAGERY IS NOT SHOWING MUCH FOR MARINE LAYER
CLOUDS SO FAR TONIGHT, JUST SOME PATCHY CLOUDS ALONG THE CENTRAL
COAST AND A FEW ALONG THE SANTA BARBARA/VENTURA COUNTY BORDER
(THOUGH THOSE LOOK TO BE SHORT LIVED). THE FORECAST HAS CLOUDS
OVERSPREADING THE CENTRAL COAST, BUT COULD EASILY SEE IT REMAINING
PATCHY AND ONLY A FEW LOCATIONS GETTING OVERNIGHT LOW CLOUDS AND
FOG (SUCH AS LOMPOC, SANTA MARIA, ETC). WITH CONTINUED 500 MB
HEIGHTS DECREASING AND INCREASING ONSHORE TRENDS, EXPECT
TEMPERATURES TO CONTINUE TO DROP, WITH HIGHS IN THE MID 70S TO
HIGH 80S TOMORROW.
FORECAST LOOKS TO BE IN SHAPE AND NO MAJOR UPDATES WERE NEEDED
THIS EVENING.
***FROM PREVIOUS DISCUSSION***
DECREASING 500 MB HEIGHTS COMBINED WITH INCREASING ONSHORE FLOW
MAINLY TO THE EAST WILL RESULT IN GRADUAL COOLING OVER THE NEXT
SEVERAL DAYS. THERE IS LINGERING POCKETS OF MODERATE HEAT RISK
OVER THE LA BASIN, OXNARD PLAIN, AND SANTA BARBARA AREA TODAY
(NO HEAT PRODUCTS NEEDED). MARINE LAYER STRATUS LIKELY TO MAKE
A RETURN TO THE SANTA MARIA VALLEY TONIGHT INTO MONDAY MORNING.
FOG IS POSSIBLE IN THE SALINAS VALLEY DURING THE EARLY TO MID-
MORNING HOURS. MID TO HIGH CLOUDS ASSOCIATED WITH THE UPCOMING
STORM SYSTEM WILL ARRIVE TO THE CENTRAL COAST TUESDAY.
GOOD CONFIDENCE IN WIDESPREAD RAIN AT TIMES WEDNESDAY & THURSDAY.
UNCERTAINTY IN TIMING AND DETAILS ESPECIALLY GIVEN THAT GUIDANCE
TENDS TO HANDLE CUT-OFF LOWS POORLY. THE RECENT TRENDS IN ECWMF
AND GFS HAVE BEEN GRADUALLY MORE OFFSHORE AND SLOWER TIMING.
SCENARIO 1 (70% CHANCE): COLD-CORE LOW PRESSURE MOVES THROUGH
THE REGION. THIS SCENARIO WOULD PROVIDE BETTER DYNAMICS WITH
INCREASED POTENTIAL FOR ORGANIZED BANDING OF MODERATE TO HEAVY
RAINFALL WITH RAINFALL TOTALS 0.5-1.5 EXCEPT LOCALLY 1.5-3 INCHES
ACROSS S-SW FACING MOUNTAINS AND FOOTHILLS. AREAS OF MOST CONCERN
WOULD BE SOUTHERN SANTA BARBARA COUNTY THROUGH LA COUNTY WHICH
HAS THE BEST CHANCE TO END UP ON THE HIGHER RANGE OF THESE TOTALS.
CONVECTION WOULD BE MORE LIKELY IN THIS SCENARIO PROVIDING AROUND
A 20% CHANCE OF THUNDERSTORMS ALONG WITH SOME CONCERN FOR
FLOODING AND DEBRIS FLOWS - ESPECIALLY NEAR RECENT BURN SCARS.
SCENARIO 2 (30% CHANCE): THE SYSTEM SLOWS AND PEAKS IN INTENSITY
WELL OFFSHORE AND WEAKENS CONSIDERABLY AS IT MOVES THROUGH THE
AREA. BOTH ECWMF AND GFS HAVE BEEN TRENDING THIS WAY THE LAST
SEVERAL CYCLES. RAIN CHANCES WOULD BE MORE SPORADIC WITH 0.25-0.50
AND LOCALLY UP TO 1-1.5 INCH FOR SOME MTN LOCATIONS. ANALOGS SHOW
THIS SCENARIO HAS RESULTED IN REDUCED IMPACTS - LOWER (BUT STILL
PRESENT) RISK FOR FLOODING AND THUNDERSTORMS.
THE FINAL SOLUTION COULD FALL IN BETWEEN THESE TWO SCENARIOS.
EITHER WAY THE WEATHER WILL FEEL CHILLY IN CONTRAST WITH HIGHS
ONLY IN THE 60S AND 70S.
LONG TERM (THU-SUN)
18/213 PM.
BY FRIDAY AND SATURDAY, THE UPPER LOW WILL HAVE MOVED EASTWARD
INTO THE GREAT BASIN. THIS WILL RESULT IN WEAK-MODERATE OFFSHORE
FLOW MAINLY FROM THE EAST. DRY CONDITIONS, LOCALLY BREEZY WINDS,
AND WARMING TEMPERATURES CAN BE EXPECTED.
THE PACIFIC-NORTH AMERICAN OSCILLATION IS EXPECTED REMAIN NEGATIVE
LIKELY THROUGH THE MONTH. THIS WEATHER PATTERN WOULD GENERALLY
FAVOR TROUGHING ON THE WEST COAST - RESULTING IN BETTER CHANCES
FOR RAIN AND COOLER TEMPERATURES.
AVIATION
19/0055Z.
AT 0020Z AT KLAX, THERE WAS A MARINE INVERSION WITH A TOP NEAR 1400
FT WITH A TEMP OF 24 DEG C.
HIGH CONFIDENCE IN VFR TAFS FOR MOST AIRFIELDS. LOWER CONFIDENCE
FOR TAFS AT KPRB, CENTRAL COAST AND LA COASTAL SITES DUE TO
UNCERTAINTIES WITH THE TIMING AND EXTENT OF LOW CLOUDS TONIGHT
INTO MON MORNING. TIMING OF ONSET AND DISSIPATION OF ANY LOW CIGS
COULD BE OFF +/- 1-2 HOURS. KPRB HAS A 10% CHANCE OF LIFR/IFR
CONDS, TIMING AND FLIGHT CATEGORY FOR CENTRAL COAST SITES HAS
LOWER CONFIDENCE, WITH 30% CHANCE OF LIFR FOR KSBP AND 20% CHANCE
OF VLIFR AT KSMX. FOR THE LA COAST, 40% CHANCE OF VFR CONDS THRU
THE PERIOD.
KLAX...MODERATE CONFIDENCE IN THE 00Z TAF. HOWEVER, THERE IS A
20 PERCENT CHANCE OF MVFR CONDS 10Z-16Z MON. ANY EAST WIND
COMPONENT IS EXPECTED TO BE 6 KT OR LESS THRU THE PERIOD.
KBUR...HIGH CONFIDENCE IN VFR 00Z TAF.
MARINE
18/814 PM.
FOR THE OUTER WATERS, MODERATE TO HIGH CONFIDENCE IN THE CURRENT
FORECAST. SMALL CRAFT ADVISORY (SCA) WINDS ARE AFFECTING THE
NORTHERN TWO ZONES (PZZ670-673) AND ARE EXPECTED TO SPREAD
SOUTHWARD OVER PZZ676 LATER TONIGHT. FOR THE NORTHERNMOST AREA,
THE GUSTY WINDS WILL ONLY LAST THROUGH LATE TONIGHT, BUT FURTHER
SOUTH THE SCA CONDS WILL PERSIST THROUGH LATE MONDAY NIGHT. THERE
IS ALSO A 40% CHANCE OF SCA WINDS AGAIN FOR THE TWO SOUTHERN ZONES
THURSDAY THROUGH FRIDAY NIGHT.
FOR THE INNER WATERS N OF POINT SAL, GENERALLY HIGH CONFIDENCE IN
THE CURRENT FORECAST. CONDS ARE EXPECTED TO LARGELY REMAIN BELOW
SCA LEVELS EXCEPT FOR A 40% CHANCE OF SCA LEVEL WIND GUSTS AT
TIMES THURSDAY NIGHT AND FRIDAY NIGHT.
FOR THE INNER WATERS S OF POINT CONCEPTION, HIGH CONFIDENCE IN
THE CURRENT FORECAST. CONDS ARE EXPECTED TO LARGELY REMAIN BELOW
SCA LEVELS EXCEPT FOR A 40% CHANCE OF SCA LEVEL WIND GUSTS FOR
THE SANTA BARBARA CHANNEL THURSDAY NIGHT AND FRIDAY NIGHT.
A MODERATE-STRENGTH STORM SYSTEM IS BECOMING MORE LIKELY IN THE
TUESDAY NIGHT THROUGH THURSDAY TIMEFRAME. IN ADDITION TO REDUCED
VISIBILITIES IN SHOWERS, THERE IS A 10-20 PERCENT CHANCE OF
THUNDERSTORMS WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT WITH THE
POSSIBILITY OF LOCALLY GUSTY AND ERRATIC WINDS AND DANGEROUS
LIGHTNING. CONDITIONS MAY BECOME FAVORABLE FOR THE FORMATION OF
WATERSPOUTS WITH THIS SYSTEM. PLEASE MONITOR THE LATEST FORECASTS
AND STATEMENTS OVER THE NEXT COUPLE OF DAYS AS WE DRAW CLOSER TO
THIS EVENT.
BEACHES
18/816 PM.
THE COMBINATION OF A WEST TO NORTHWEST SWELL AND A 3-FT SOUTHERLY
SWELL WILL BRING ELEVATED SURF OF 3 TO 6 FEET MAINLY TO SOUTH AND
SOUTHWEST-FACING BEACHES OF VENTURA AND LOS ANGELES COUNTIES
THROUGH TUESDAY MORNING.
IN ADDITION TO THE ELEVATED SURF, DANGEROUS RIP CURRENTS CAN BE
EXPECTED. MINOR BEACH EROSION AND TIDAL OVERFLOWS CANNOT BE RULED
OUT FOR LOW-LYING BEACH AREAS AROUND THE TIMES OF HIGH TIDES.
LOX WATCHES/WARNINGS/ADVISORIES
CA...BEACH HAZARDS STATEMENT IN EFFECT THROUGH TUESDAY MORNING FOR
ZONES 354-362-366. (SEE LAXCFWLOX).
PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT MONDAY FOR ZONE
670. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT TUESDAY FOR
ZONE 673. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT FROM 3 AM MONDAY TO 3 AM PDT
TUESDAY FOR ZONE 676. (SEE LAXMWWLOX).
PUBLIC...DB/KL
AVIATION...CILIBERTI
MARINE...SIRARD/CILIBERTI
BEACHES...SIRARD/CILIBERTI
SYNOPSIS...RM/CILIBERTI
WEATHER.GOV/LOSANGELES
EXPERIMENTAL GRAPHICAL HAZARDOUS WEATHER OUTLOOK AT:
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=LOX
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