571
FXUS66 KLOX 130342
AFDLOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
842 PM PDT SUN OCT 12 2025
SYNOPSIS
12/606 PM.
AN EARLY SEASON STORM SYSTEM WILL MOVE ACROSS THE AREA LATE
MONDAY THROUGH TUESDAY, WITH MOST OF THE RAINFALL LIKELY MONDAY
NIGHT THROUGH TUESDAY. EXPECT WIDESPREAD LIGHT TO MODERATE RAIN
WITH POTENTIAL FOR LOCALLY HEAVY SHOWERS AND THUNDERSTORMS, AND
GUSTY SOUTHERLY WINDS.
SHORT TERM (SUN-WED)
12/839 PM.
***UPDATE***
GUSTY NORTH WINDS ARE AFFECTING SOUTHWEST SANTA BARBARA COUNTY
THIS EVENING, BETWEEN GAVIOTA AND REFUGIO. AT THIS TIME GUSTS ARE
JUST BELOW ADVISORY LEVEL AND MODELS INDICATE WINDS PEAKING AROUND
03Z (8 PM). SO WILL HOLD OFF ON ISSUING A WIND ADVISORY BASED ON
THE SHORT DURATION AND LIMITED AREA OF THE STRONGER WINDS.
OTHERWISE, THE FORECAST REMAINS ON TRACK FOR A STORM SYSTEM
APPROACHING THE AREA FROM THE PACIFIC NORTHWEST. AN UPPER CLOSED
LOW IS FORECAST TO TRACK SOUTHWARD ALONG THE WEST COAST TONIGHT
THROUGH TUESDAY MORNING, AND THEN SHIFT EASTWARD INTO THE GREAT
BASIN TUESDAY NIGHT. THIS COLD AND DYNAMIC SYSTEM WILL BRING
INCREASING SOUTH WINDS TO MUCH OF THE AREA, UNSEASONABLY LOW SNOW
LEVELS AROUND 6,000 FEET, RAINFALL TOTALS RANGING FROM 0.75 INCH
TO 3.50 INCHES, AND WIDESPREAD THUNDERSTORM CHANCES. THERE IS A
RISK OF STRONG THUNDERSTORMS DEVELOPING AT TIMES, WITH HEAVY
DOWNPOURS, STRONG GUSTY WINDS AND HAIL.
BY LATE TUESDAY NIGHT INTO WEDNESDAY EXPECT CLEARING AND MUCH
QUIETER WEATHER AS THE LOW SHIFTS EAST OF THE AREA.
***FROM PREVIOUS DISCUSSION***
WINDS...
ON MONDAY AND TUESDAY, EXPECT A DRAMATIC INCREASE IN SOUTH TO
SOUTHWEST WINDS AS THE UPPER LOW IMPACTS THE AREA. WINDS WILL
FIRST INCREASE ACROSS THE DESERTS AND INTERIOR SECTIONS ON MONDAY
THEN INCREASE WEST OF THE MOUNTAINS MONDAY NIGHT AND TUESDAY. AT
THIS TIME, ADVISORY-LEVEL WINDS ARE LIKELY ACROSS THE DESERTS AND
INTERIOR SECTIONS (WITH A CHANCE OF WARNING LEVEL WINDS ACROSS THE
LA MOUNTAINS AND ANTELOPE VALLEY FOOTHILLS). FOR COASTAL AND
VALLEY AREAS, THERE IS A 30-50% CHANCE OF WIDESPREAD ADVISORY
LEVEL WINDS MONDAY NIGHT AND TUESDAY.
PRECIPITATION...
ALL SYSTEMS ARE STILL A BIG "GO" FOR THE STORM MONDAY NIGHT
THROUGH TUESDAY NIGHT. BASED ON LATEST GUIDANCE, EXPECTED RAINFALL
TOTALS HAVE ADJUSTED FROM PREVIOUS THINKING. RIGHT NOW, COASTAL
AND VALLEY AREAS CAN EXPECT 0.75-1.50 INCHES OF RAINFALL WITH 1.50
TO 3.50 INCHES ACROSS THE MOUNTAINS/FOOTHILLS. OF COURSE, GIVEN
THE SOUTHERLY FLOW, SOME FAVORED UPSLOPE AREAS COULD RECEIVE EVEN
HIGHER AMOUNTS.
AS FOR RAINFALL RATES, GENERALLY WILL BE EXPECTING HOURLY RATES
OF 0.25-0.50 INCHES. HOWEVER, HIGH RESOLUTION MODELS ARE STILL
INDICATING THE POTENTIAL FOR A QLCS-TYPE FEATURE ON TUESDAY WHICH
WOULD GENERATE HIGHER RATES OF 0.50-1.00 INCHES PER HOUR OR EVEN
HIGHER. ADDITIONALLY, SUB-HOURLY RATES COULD BE QUITE INTENSE. SO,
GIVEN THE POTENTIAL FOR RAIN RATES TO MEET/EXCEED USGS THRESHOLDS
FOR THE BURN SCARS, A FLOOD WATCH WILL BE IN EFFECT FOR THE BURN
AREAS (SEE LAXFFALOX FOR DETAILS). THERE WILL BE THE POTENTIAL FOR
SIGNIFICANT MUD/DEBRIS FLOW ISSUES.
AS FOR THUNDERSTORMS, THE RISK STILL REMAINS FOR THE AREA. LOOKING
AT THE MODEL SOLUTIONS, THE SETUP IS LOOKING MORE CONDUCIVE FOR
WIDESPREAD THUNDERSTORM POTENTIAL FOR ALL AREAS MONDAY NIGHT AND
TUESDAY. ALTHOUGH CAPE VALUES ARE NOT IMPRESSIVE, THE POTENTIAL
DIFFLUENT FLOW ALOFT, STRONG JET DYNAMICS AND LOW LEVEL WIND SHEAR
WILL BRING THE POSSIBILITY OF STRONG THUNDERSTORMS (GUSTY WINDS,
HAIL AND HEAVY RAIN) ALONG WITH WATERSPOUTS/WEAK TORNADOES. FOR
REFERENCE, THE SETUP IS LOOKING SIMILAR TO CONDITIONS INDICATED BY
THE HALES STUDY FOR SOUTHWESTERN CALIFORNIA SEVERE WEATHER.
FINALLY, THERE STILL LOOKS TO BE THE POTENTIAL FOR SOME SNOWFALL
ACCUMULATIONS AT THE HIGHER ELEVATIONS. BASED ON THICKNESS AND
WET BULB ZERO FORECASTS, SNOW LEVELS LOOK TO DROP INTO THE
5500-7000 FOOT RANGE ON TUESDAY (BUT LOCALLY LOWER WITH ANY
SIGNIFICANT CONVECTION). SO, SEVERAL INCHES OF SNOWFALL
ACCUMULATION WILL BE LIKELY ABOVE 6000 FEET. GIVEN THE STRONG
SOUTHERLY WINDS ANTICIPATED, WINTER STORM CRITERIA CONDITIONS
COULD DEVELOP. WILL LET THE NEXT COUPLE OF SHIFTS LOOK AT THE NEXT
SUITE OF MODEL RUNS TO MAKE THE FINAL DETERMINATION FOR ANY
WINTER PRODUCTS.
LONG TERM (THU-SUN)
12/200 PM.
FOR THE EXTENDED, 12Z MODELS CONTINUE TO EXHIBIT GOOD SYNOPTIC
AGREEMENT. AT UPPER LEVELS, RIDGE GRADUALLY BUILDS OVER THE
EASTERN PACIFIC THURSDAY THROUGH SATURDAY, BEFORE WEAKENING ON
SUNDAY AS A TROUGH MOVES ACROSS NORTHERN CALIFORNIA/PACIFIC
NORTHWEST. NEAR THE SURFACE, WEAK DIURNAL GRADIENTS WILL PREVAIL.
FORECAST-WISE, NO SIGNIFICANT ISSUES ARE EXPECTED. FOR THURSDAY
THROUGH SATURDAY, DRY CONDITIONS ARE EXPECTED ALONG WITH A WARMING
TREND. AT TIMES, THERE COULD BE SOME OFFSHORE WINDS ACROSS THE
AREA, BUT ANY WINDS LOOK TO BE WEAK (IF THEY DO DEVELOP). ON
SUNDAY, AS THE TROUGH ROLLS ACROSS THE WEST COAST, COOLER
CONDITIONS ARE ANTICIPATED ALONG WITH THE POSSIBILITY OF SOME
ADDITIONAL RAINFALL (BUT CONFIDENCE IN THAT POTENTIAL REMAINS VERY
LOW).
AVIATION
13/0053Z.
AT 0007Z AT KLAX, THE MARINE LAYER WAS 700 FT DEEP. THE TOP OF
THE INVERSION WAS NEAR 1800 FT WITH A TEMPERATURE OF 19 C.
LOW CONFIDENCE IN THE 00Z TAFS FOR THE COASTAL AND VALLEYS SITES
AND HIGH CONFIDENCE IN THE DESERT SITES.
GENERALLY EXPECTING VFR CONDITIONS THROUGH THE PERIOD, BUT THERE
IS A 30% CHANCE OF STRATUS AFFECTING PORTIONS OF THE COAST AND
VALLEYS, WITH GENERALLY IFR TO LIFR POSSIBLE NORTH OF POINT
CONCEPTION AND IFR TO MVFR FURTHER SOUTH.
MODERATE CONFIDENCE IN WIND FORECASTS.
KLAX...LOW TO MODERATE CONFIDENCE IN THE 00Z TAF. MVFR CIGS
FORECAST TO ARRIVE BY 09Z BUT THE TIMING COULD DIFFER BY +/1 2
HOURS, WITH A 20-30% CHANCE THAT NO LOW CIGS OCCUR. THERE IS A
60-70% CHANCE OF AN EAST WIND COMPONENT REACHING 7-8 KNOTS FROM
08Z MON THRU 18Z MON.
KBUR...HIGH CONFIDENCE IN THE 00Z TAF. VFR CONDITIONS EXPECTED
THRU FORECAST PERIOD, BUT WITH A 10-20% CHANCE OF MVFR CIGS DURING
THE OVERNIGHT PERIOD, MOST LIKELY BETWEEN 10Z-16Z.
MARINE
12/815 PM.
MONDAY EVENING THROUGH TUESDAY AFTERNOON, A STORM SYSTEM AND
ASSOCIATED COLD FRONT WILL MOVE ACROSS THE REGION. THIS WILL BRING
A 20-40% CHANCE OF THUNDERSTORMS ACROSS ALL THE COASTAL WATERS
DURING THAT TIMEFRAME.
SMALL CRAFT ADVISORY (SCA) LEVEL WINDS AND SEAS WILL CONTINUE
ACROSS THE WATERS NORTH OF POINT SAL (PZZ670/645) THROUGH MONDAY
MORNING. WINDS WILL REMAIN STRONG FROM POINT CONCEPTION SOUTH TO
SAN NICOLAS ISLAND, THUS A GALE WARNING REMAINS IN EFFECT ACROSS
THIS AREA THROUGH LATE TONIGHT (PZZ673/676). SCA CONDITIONS ARE
LIKELY TO LINGER THROUGH MONDAY MORNING FOR ALL OF THE OUTER
WATERS AND PZZ645, AND THROUGH THE AFTERNOON FOR PZZ676.
INCREASING SOUTH WINDS ARE THEN EXPECTED MONDAY NIGHT AS THE COLD
FRONT APPROACHES FROM THE NORTH. STRONG SCA WINDS ARE EXPECTED
ALONG WITH THE FRONT, THEN DECREASING FROM THE WEST BEHIND THE
FRONT TUESDAY AND TUESDAY NIGHT. WEDNESDAY THROUGH THURSDAY
INCREASING NW WINDS WILL LIKELY REACH SCA LEVELS ONCE AGAIN.
FOR THE INNER WATERS SOUTH OF POINT CONCEPTION, WINDS ARE EXPECTED
TO REMAIN AT SCA LEVELS ACROSS WESTERN & SOUTHERN PORTIONS OF THE
SANTA BARBARA CHANNEL THROUGH LATE TONIGHT, ALONG WITH CHOPPY SEAS.
GOOD CONFIDENCE THAT WINDS CALM TO BELOW SCA LEVELS BY EARLY
MONDAY MORNING. MONDAY NIGHT AND TUESDAY INCREASING S TO SW WINDS
ARE EXPECTED ACROSS THE AREA.
ANY THUNDERSTORM THAT FORMS MAY BE CAPABLE OF FREQUENT CLOUD TO
SURFACE LIGHTNING, GUSTY AND ERRATIC WINDS, SMALL HAIL, AND EVEN A
WATERSPOUT. ADDITIONALLY, WIDESPREAD SCA LEVEL SW WINDS AND SEAS,
WITH A MODERATE CHANCE OF GALES BETWEEN MONDAY NIGHT AND TUESDAY
NIGHT DUE TO THE AFOREMENTIONED STORM.
LOX WATCHES/WARNINGS/ADVISORIES
CA...FLOOD WATCH IN EFFECT FROM MONDAY EVENING THROUGH TUESDAY
AFTERNOON FOR ZONES
38-88-342-344-345-348-353-355-358-362-368>375-377>380-548. (SEE LAXFFALOX).
PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 9 AM PDT MONDAY FOR
ZONES 645-670. (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT MONDAY FOR ZONE
650. (SEE LAXMWWLOX).
GALE WARNING IN EFFECT UNTIL 3 AM PDT MONDAY FOR ZONES
673-676. (SEE LAXMWWLOX).
PUBLIC...THOMPSON/CILIBERTI
AVIATION...CILIBERTI
MARINE...CILIBERTI
SYNOPSIS...SCHOENFELD/CILIBERTI
WEATHER.GOV/LOSANGELES
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