Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 050349
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
830 PM PDT TUE AUG 4 2015

.SYNOPSIS...

WEAK HIGH PRESSURE WILL ALLOW FOR A SLIGHT WARM UP INTO MID-WEEK.
HEADING INTO THE WEEKEND...COASTAL CLOUDS WILL BUILD INTO THE
COASTAL VALLEYS EACH MORNING WITH CONSIDERABLY COOLER TEMPERATURES
AS LOW PRESSURE PASSES TO THE NORTH. EARLY NEXT WEEK TEMPERATURES
WILL REBOUND AS HIGH PRESSURE BUILDS BACK INTO THE REGION.

&&

.SHORT TERM (TONIGHT-FRI)...
LONG FETCH OF SOUTHWEST FLOW ENTRAINING SOME HIGHER LEVEL CLOUDS
INTO SOUTHWEST CALIFORNIA THIS EVENING. THE ORIGIN OF THIS UPPER
LEVEL MOISTURE IS FROM TROPICAL STORM GUILLERMO (CURRENTLY 375 MILES
EAST OF HILO HAWAII). MODEL CROSS SECTIONS AND SATELLITE TRENDS SHOWING
THE THICKEST MID AND HIGH LEVEL CLOUD COVERAGE NORTH OF POINT
CONCEPTION...AND WILL BUMP UP TO MOSTLY CLOUDY WORDING FOR REMAINDER
OF TONIGHT INTO WEDNESDAY MORNING.

OTHER SHORT TERM WEATHER CONCERN THIS EVENING IS THE GUSTY SUNDOWNER
WINDS ACROSS THE WESTERN PORTIONS OF THE SBA SOUTH COAST AND SANTA YNEZ
RANGE...WHERE A WIND ADVISORY IS IN EFFECT TIL 3 AM TONIGHT. CURRENT
SANTA BARBARA-SANTA MARIA PRESSURE GRADIENT IS -4.5 MB...WHICH IS
COMPARABLE TO LAST NIGHT`S READINGS. AS OF 8 PM...GAVIOTA WIND GUST
PEAKED AT 43 MPH...REFUGIO HILLS AT 48 MPH...LAS FLORES CANYON AT 33 MPH...
AND SAN MARCOS PASS AT 34 MPH. TEMPERATURES ALSO SOARED WELL INTO THE 80S
ACROSS MUCH OF THE SBA SOUTH COAST LATE THIS AFTERNOON AND EARLY EVENING...INCLUDING
A RECORD HIGH OF 86 DEGREES AT SANTA BARBARA AIRPORT (WHICH TIED THE PREVIOUS
RECORD IN 1976).

MINIMAL STRATUS EXPECTED TONIGHT DUE TO INFLUX OF MID AND HIGH LEVEL CLOUDS
OVER AREA. TOMORROW IS STILL EXPECTED TO BE WARMEST DAY OF THE WEEK FOR
MANY AREAS. THE EXCEPTION MAY BE THE SBA SOUTH COAST...WHERE SUNDOWNER WINDS
SHOULD BE WEAKER TOMORROW AFTERNOON/EVENING.

TAKING A LOOK AT 00Z NAM...WILL HAVE TO KEEP A CLOSE EYE ON THURSDAY
AFTERNOON/EVENING TIME FRAME. DURING THIS TIME...A CLOSED LOW OFF THE CENTRAL
COAST IS FORECAST TO EJECT NORTHEASTWARD WITH THE CENTER OF THE LOW EXPECTED
TO MAKE LANDFALL NEAR THE MONTEREY BAY SOMETIME THURSDAY NIGHT. IN BETWEEN THE LOW
OFF THE COAST AND THE WESTERN PERIPHERY OF THE HIGH PRESSURE SYSTEM OVER THE
DESERT SOUTHWEST...THE NAM CONTINUES TO STEER SOME MID LEVEL MOISTURE IN FROM
THE SOUTH INTO SOUTHWEST CALIFORNIA ON THRUSDAY. THE BEST MID LEVEL MOISTURE FOR
OUR FORECAST AREA WILL BE FOCUSED OVER LOS ANGELES AND VENTURA COUNTIES. WILL LIKELY
SEE INCREASING MID LEVEL CLOUDS ON THURSDAY INTO THURSDAY EVENING ACROSS LOS ANGELES
AND VENTURA COUNTIES. THERE IS SOME MID LEVEL INSTABILITY AND LIFT ASSOCIATED WITH
THIS MID LEVEL MOISTURE. 00Z NAM CONTINUES TO GENERATE SOME LIGHT QPF THURSDAY
AFTERNOON/EVENING. FOR NOW...THINKING THERE IS GOOD CHANCE OF SOME SPRINKLES WITH
THIS TYPE OF PATTERN...AND CANNOT TOTALLY RULE OUT THE POSSIBILITY OF LIGHT SHOWERS.
FOR NOW...WILL KEEP POPS AROUND 10 PERCENT. ALSO OF NOTE...IS THE 75 KNOT JET CORE
ROUNDING THE BASE OF THE UPPER LOW ON THURSDAY AFTERNOON/EVENING OFF THE CENTRAL
COAST. WHILE MOISTURE IS LIMITED...WILL HAVE TO KEEP AN EYE OUT FOR POSSIBLE SHOWERS
OR ELEVATED CONVECTION FOR COASTAL SLO COUNTY AND THE ADJACENT COASTAL WATERS
ON THURSDAY AFTERNOON/EVENING. 00Z NAM SHOWING VALUES OF AROUND 1000 J/KG OF MUCAPE
FOR THURSDAY EVENING OFF THE COAST OF SLO COUNTY...INDICATIVE OF THE ELEVATED
INSTABILITY. WILL NUDGE POPS UP SLIGHTLY FOR SLO COUNTY AND ADJACENT COASTAL WATERS
UP TO AROUND 10 PERCENT DURING THIS TIME FRAME TO ACCOUNT FOR THIS VERY SLIGHT POSSIBILITY
OF LIGHT SHOWERS OR ELEVATED (MOSTLY DRY) THUNDERSTORMS).

*** FROM PREVIOUS DISCUSSION ***


.LONG TERM (SAT-TUE)...

HEIGHT/THICKNESS VALUES BOTTOM OUT ON SATURDAY MORNING AS THE UPPER
LOW OPENS UP AND PASSES TO THE NORTH. WITH A DEVELOPING UPPER-LEVEL
TROUGH OFF THE PAC NW COAST AND A BUILDING RIDGE OVER NM/TX...MODELS
AGREE THAT SOUTHERN CA WILL REMAIN IN DRY SW FLOW ALOFT THROUGH
EARLY NEXT WEEK. THE BUILDING RIDGE TO THE EAST WILL RESULT IN
GRADUAL HEIGHT/THICKNESS RISES...WHICH SHOULD BRING A GRADUAL
WARMING TREND SAT-TUE. TEMPERATURES SHOULD WARM BACK TO NEAR NORMAL
IN MOST PLACES BY MONDAY OR TUESDAY. MARINE LAYER CLOUD COVERAGE
SHOULD PEAK FRIDAY NIGHT/SAT MORNING...THEN GRADUAL SHRINK THROUGH
EARLY NEXT WEEK. THERE IS AN OUTSIDE CHANCE OF SOME MONSOONAL FLOW
RETURNING BY THE MIDDLE OF NEXT WEEK.

&&

.AVIATION... 04/2345Z

AT 2340Z AT KLAX...THE MARINE LAYER WAS 1000 FEET DEEP.  THE TOP OF THE
INVERSION WAS AT 3000 FEET AND HAD A TEMPERATURE OF 25 DEGREES CELSIUS.

OVERALL... MODERATE CONFIDENCE IN THE 00Z COASTAL TAFS AND HIGH
CONFIDENCE IN ALL OTHERS.  CURRENTLY EXPECTING CIGS DUE TO
OVERNIGHT/MORNING LOW CLOUDS ONLY ALONG THE COAST FROM POINT
CONCEPTION NORTHWARD BUT WITH A TWENTY PERCENT CHANCE OF CIGS
DEVELOPING IN VENTURA AND LOS ANGELES COUNTY SITES.  ELSEWHERE VFR
CONDITIONS WILL PREVAIL. VCNTY KSBA...ANOTHER ROUND OF GUSTY SUNDOWNER
WINDS IN NEARBY CANYONS WILL BRING GOOD POTENTIAL FOR STG UDDFS AND LLWS.

KLAX...MODERATE CONFIDENCE IN THE 00Z TAF.  TWENTY PERCENT CHANCE OF
CIGS DUE TO OVERNIGHT/EARLY MORNING LOW CLOUDS...OTHERWISE VFR CONDITIONS
WILL PREVAIL.

KBUR...HIGH CONFIDENCE IN THE 00Z TAF.

&&

.MARINE... 04/800 PM

ACROSS THE OUTER WATERS... SMALL CRAFT ADVISORY CONDITIONS WILL
CONTINUE THROUGH LATE WEDNESDAY THOUGH WINDS MAY DROP BELOW CRITERIA
FOR A FEW HOURS DURING THE MORNING HOURS. CONDITIONS SHOULD BE BELOW ADVISORY
CRITERIA THURSDAY AND FRIDAY THEN POTENTIALLY INCREASE AGAIN DURING
THE WEEKEND.

ACROSS THE INNER WATERS... SMALL CRAFT ADVISORY CONDITIONS WILL
CONTINUE TONIGHT IN THE WESTERN HALF OF THE SANTA BARBARA CHANNEL.
CONDITIONS SHOULD REMAIN BELOW ADVISORY CRITERIA FROM WEDNESDAY
THROUGH THE END OF THE WEEK...ALTHOUGH COULD SEE SOME LOCAL WIND GUSTS
UP TO 25 KNOTS ACROSS THE WESTERN HALF OF THE SBA CHANNEL.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).

&&
$$

PUBLIC...GOMBERG/SUKUP
AVIATION...GOMBERG
MARINE...GOMBERG
SYNOPSIS...MUNROE

WWW.WEATHER.GOV/LOSANGELES


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