Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 220319
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
815 PM PDT THU AUG 21 2014

.SYNOPSIS...
ONSHORE FLOW WITH NIGHT AND MORNING LOW CLOUDS AND FOG WILL KEEP
TEMPERATURES BELOW NORMAL THROUGH THE WEEKEND. A GRADUAL WARMING
TREND SHOULD  FOLLOW NEXT WEEK AS A RIDGE OF HIGH PRESSURE BUILDS
ACROSS THE REGION.

&&

.SHORT TERM (TONIGHT-SUN)...
UPPER LEVEL LOW PRESSURE SYSTEM THAT BROUGHT ANOTHER ACTIVE DAY OF
THUNDERSTORMS TO SOUTHEAST CALIFORNIA HAS NOW SHIFTED EASTWARD
TOWARDS THE COLORADO RIVER VALLEY. FOR OUR AREA...SOME RESIDUAL MOISTURE
AND INSTABILITY MOSTLY GENERATED CUMULUS CLOUDS ACROSS THE LOCAL
MOUNTAINS AND ANTELOPE VALLEY. ONE STORM DID DEVELOP LATE THIS AFTERNOON
ACROSS THE EXTREME EASTERN PORTION OF THE ANTELOPE VALLEY BUT DID NOT
HAVE ANY ASSOCIATED LIGHTNING. AS THE LOW PRESSURE SYSTEM CONTINUES
TO TRACK INTO ARIZONA OVERNIGHT...THE ATMOSPHERE WILL DRY AND STABILIZE
ACROSS OUR FORECAST AREA. AS A RESULT...NO THREAT OF THUNDERSTORMS
EXPECTED THROUGH THE WEEKEND.

AS THE MARINE INVERSION RESTRENGTHENS OVERNIGHT...A MORE TYPICAL
MARINE LAYER CLOUD FORMATION IS EXPECTED FOR COASTAL AREAS AS WELL
AS SOME COASTAL VALLEY. MARINE LAYER EXPECTED TO BE AT LEAST 1500
FEET FOR AREAS SOUTH OF POINT CONCEPTION AND AROUND 1000 FEET FOR
NORTH OF POINT CONCEPTION. THE NIGHT AND MORNING MARINE LAYER CLOUDS
SHOULD PERSIST THROUGH THE WEEKEND...WITH TEMPERATURES REMAINING
SLIGHTLY BELOW NORMAL. IN FACT...WARMEST VALLEY LOCATIONS ARE ONLY
EXPECTED TO CLIMB TO AROUND 90 DEGREES EACH DAY.

*** FROM PREVIOUS DISCUSSION...

.LONG TERM (MON-WED)...
WEATHER CONDITIONS IN THE EXTENDED FORECAST WILL BE VERY SIMILAR TO
THE SHORTER TERM IN THAT TEMPERATURES SHOULD REMAIN RELATIVELY CLOSE
TO NORMAL WITH THE PRIMARY INFLUENCE ON ANY VARIATION BEING THE
MARINE LAYER.  THERE IS A BIT OF A DIFFERENCE IN THE GUIDANCE
THOUGH... WITH INDICATIONS OF A WEAK RIDGE BUILDING OVER THE REGION
VERSUS A WEAK TROUGH DROPPING THROUGH.  THIS IS MOSTLY INDICATIVE OF
HOW WEAK ANY PARTICULAR SIGNAL IS AND MILD PERIOD OF WEATHER IN
GENERAL SHOULD BE THE RESULT.

&&

.AVIATION...21/2335Z.
SATELLITE IMAGERY SHOWING MOSTLY CLEAR SKIES ACROSS THE REGION LATE THIS
AFTERNOON WITH THE EXCEPTION OF SOME CUMULUS CLOUDS OVER THE MOUNTAINS
AND DESERTS. RESIDUAL MOISTURE AND INSTABILITY WILL BRING ISOLATED STORMS
ACROSS EASTERN SAN GABRIELS AND ANTELOPE VALLEY TIL SUNDOWN...WITH
POSSIBLE THUNDERSTORMS IN VICINITY OF PALMDALE. MOSTLY IFR/MVFR CIGS
EXPECTED TO RETURN TO COASTAL TAF SITES TONIGHT...BUT TIMING IS
QUESTIONABLE. WITH SHALLOWER MARINE LAYER NORTH OF POINT
CONCEPTION...THERE IS A CHANCE OF BRIEF LIFR CONDITIONS AT KSMX AND
KSBP. ALSO A 30 PERCENT CHANCE OF IFR CIGS REACHING KBUR AND KVNY
AROUND SUNRISE.


KLAX...MVFR CIGS EXPECTED TO RETURN TO KLAX TONIGHT...BUT TIMING IS
QUESTIONABLE. BUT THERE IS A 20 PERCENT CHANCE THAT MARINE LAYER CLOUDS
WILL NOT PUSH INTO THE AIRFIELD.

KBUR...MOSTLY VFR CONDITIONS EXPECTED THROUGH PERIOD WITH THE EXCEPTION
OF SOME EARLY MORNING VSBY RESTRICTIONS DUE TO HAZE. THERE IS A 30 PERCENT
CHANCE OF IFR CIGS REACHING KBUR AROUND SUNRISE.

&&

.MARINE...21/800 PM...

TROPICAL STORM LOWELL...CENTERED AROUND 950 MILES SOUTH-SOUTHWEST OF LOS
ANGELES THIS EVENING WILL BRING 4 TO 5 FOOT SOUTHERLY SWELL THROUGH
THE WEEKEND. PEAK SWELL IS EXPECTED TO OCCUR FRIDAY AFTERNOON THROUGH
SUNDAY MORNING.

ANOTHER TROPICAL DISTURBANCE IS EXPECTED TO DEVELOP OFF THE CENTRAL
AMERICAN COAST AND WILL POTENTIALLY DEVELOP INTO ANOTHER HURRICANE
IN THE EASTERN PACIFIC EARLY NEXT WEEK. WAVE MODELS ARE SHOWING THE
POTENTIAL FOR EVEN LARGER SOUTHERLY SWELL WITH THIS EVENT REACHING
THE SOUTHERN CALIFORNIA COASTAL WATERS BY THE MIDDLE OF NEXT WEEK.

&&

.BEACH HAZARDS...21/800 PM...

A BEACH HAZARDS STATEMENT IS IN EFFECT THROUGH SUNDAY AFTERNOON
FOR SOUTH FACING BEACHES OF LOS ANGELES AND VENTURA COUNTIES.
SOUTHERLY SWELL FROM TROPICAL STORM LOWELL IS THE CAUSE OF THIS INCREASING
SURF AND HIGH RIP CURRENT RISK ACROSS SOUTH FACING BEACHES...WHICH WILL
CONTINUE THROUGH THE WEEKEND. SURF HAS BEEN BUILDING THIS AFTERNOON
AND EVENING...WITH BREAKERS UP TO 8 FEET BEING OBSERVED AT PORT
HUENEME AND 6 FEET AT CABRILLO BEACH. THE PEAK OF THIS SURF EVENT
IS EXPECTED TO BE FRIDAY AFTERNOON THROUGH SUNDAY MORNING...WHEN
BREAKERS OF 5 TO 7 FEET WILL BE MORE WIDESPREAD ACROSS SOUTH FACING
BEACHES...WITH LOCAL SETS UP TO 9 FEET IN FAVORED LOCATIONS. DURING THIS
TIME...THERE IS A CHANCE THAT THE BEACH HAZARDS STATEMENT WILL
NEED TO BE UPGRADED TO A HIGH SURF ADVISORY. AREAS MOST SUSCEPTIBLE
TO THE ELEVATED SURF AND DANGEROUS RIP CURRENTS WILL BE THE PALOS
VERDES PENINSULA INCLUDING CABRILLO BEACH...AS WELL AS MALIBU AND
ZUMA BEACHES. FOR VENTURA COUNTY...PORT HUENEME AND POINT MUGU WILL
BE AT HIGHEST RISK.

THERE IS THE POTENTIAL FOR AN EVEN HIGHER SOUTHERLY SURF EVENT FOR
THE BEACHES OF SOUTHERN CALIFORNIA BY THE MIDDLE OF NEXT WEEK AS
LONG RANGE COMPUTER MODELS SHOW ANOTHER HURRICANE SPINNING UP IN
THE EASTERN PACIFIC.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).
BEACH HAZARDS STATEMENT (SEE LAXCFWLOX).

&&
$$

PUBLIC...GOMBERG/KJ
AVIATION...GOMBERG
MARINE...GOMBERG
BEACH HAZARDS...GOMBERG
SYNOPSIS...GOMBERG

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