Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 180008 AAA
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
510 PM PDT THU APR 17 2014

...UPDATE FOR NEW AVIATION DISCUSSION...

.SYNOPSIS...

ONSHORE FLOW WILL CONTINUE TO BRING COOL TEMPERATURES TO THE AREA
THROUGH FRIDAY WITH PARTLY TO MOSTLY CLOUDY SKIES. MORNING DRIZZLE
IS POSSIBLE AT COASTS AND VALLEYS FRIDAY MORNING. EXPECT WARMER
WEATHER OVER THE WEEKEND INTO MONDAY BEFORE A TROUGH APPROACHES ON
TUESDAY BRINGING CLOUDS AND A COOLING TREND.

&&

.SHORT TERM (TODAY-SUN)...HIGH CLOUDS FROM AN UPPER LEVEL LOW ABOUT
300 MILES SW OF PT CONCEPTION HAVE BEEN OBSCURING THE SUN FOR MOST
AREAS TODAY. SO FAR THE MOISTURE IS BASED AROUND 400MB BUT IS
EXPECTED LOWER TO AROUND 600MB TONIGHT AS THE LOW AND ASSOCIATED
TROF MOVE CLOSER. TOO MUCH DRY AIR BELOW TO GET ANY PRECIP, THOUGH A
DOUBLING OF THIS MORNING`S 2000` MARINE LYR MAY HELP GENERATE SOME
DRIZZLE IF THE HIGHER CLOUDS DON`T PREVENT THE LOWER CLOUDS FROM
FORMING. TROF WILL BE MOVING EAST FRIDAY NIGHT BUT PLENTY OF CLOUDS
UNTIL THEN. HIGHS FRIDAY A FEW DEGREES COOLER THAN TODAY.

WEAK RIDGING WILL DEVELOP OVER THE WEEKEND, PEAKING SUNDAY INTO
EARLY MONDAY. EXPECTING ABOUT 5 DEGREES OF WARMING EACH DAY THIS
WEEKEND WITH HIGHS REACHING THE LOW TO MID 80S FOR THE WARMER
VALLEYS BY SUNDAY. MOSTLY 60S TO LOWER 70S FOR THE COAST. MARINE LYR
CLOUDS EXPECTED TO STILL BE AROUND, BUT LOWERING IN DEPTH WITH
EARLIER CLEARING AS THE RIDGE BUILDS. RISING SURFACE PRESSURES TO
THE NORTHWEST SATURDAY WILL HELP GENERATE A WEAK SUNDOWNER IN SRN
SBA COUNTY SAT EVENING BUT LIKELY BELOW ADVISORY LEVELS. SIMILAR
WINDS ALSO EXPECTED FOR THE GRAPEVINE AREA.

.LONG TERM (MON-THU)...AN APPROACHING TROF WILL GENERATE STRONG
ONSHORE TRENDS MONDAY AFTERNOON, LEADING TO COASTAL COOLING AND A
LEVELING OFF OF TEMPS FOR THE VALLEYS. MODELS IN PRETTY GOOD
AGREEMENT NOW WITH THE TIMING AND STRENGTH OF THE TROF FOR TUE,
WHICH NOW LOOKS LIKE A BLEND OF THE EARLIER RUNS OF THE STRONGER GFS
AND WEAKER ECMWF. IRONICALLY THE ECMWF NOW HAS SLIGHTLY LOWER
HEIGHTS ACROSS THE AREA TUESDAY, THOUGH BOTH SOLUTIONS INDICATE VERY
LITTLE MOISTURE TO WORK WITH AND NO PRECIP OTHER THAN POSSIBLY SOME
MARINE LYR DRIZZLE DURING THE MORNING. OBVIOUSLY QUITE A BIT COOLER
TUESDAY WITH PLENTY OF CLOUDS AROUND AND A SLOW CLEARING MARINE LYR.
PRETTY STRONG ONSHORE GRADIENT TUESDAY AFTERNOON, POSSIBLY ADVISORY
LEVEL FOR THE ANTELOPE VALLEY. STILL COOL AND BREEZY WEDNESDAY
THOUGH WITH MUCH MORE SUNSHINE. A WARMUP EXPECTED BY THU WITH VERY
WEAK RIDGING OVERHEAD.

&&

.AVIATION...18/0000Z...GENERALLY HI CONFIDENCE IN THE 00Z TAF...
EXCEPT MODERATE CONFIDENCE IN THE ONSET OF LOW CLOUDS AND MVFR
CONDITIONS FOR KPRB...KLAX...KLGB...KBUR AND KVNY WHICH MAY BE AN
HOUR OR TWO TOO EARLY...EXCEPT OFF PLUS/MINUS AND HOUR OR TWO FOR
KBUR AND KVNY. OTHERWISE...HI CONFIDENCE OF MVFR CIGS AT THE COASTAL
AND VLY AIRFIELDS TONIGHT INTO FRI MORNING...EXCEPT EXTENDING THRU
THE AFTERNOON AT KSBA...KOXR...KLAX...KLGB...KBUR AND KVNY.
HOWEVER...CIGS SHOULD LIFT TO MVFR FOR KBUR AND KVNY BY 22Z FRI.

KLAX...GENERALLY HI CONFIDENCE IN THE 00Z TAF. LOW CLOUDS AND MVFR
CIGS ARE FORECAST TO DEVELOP AT THE AIRFIELD BY 03Z ALTHO THERE IS
MODERATE CONFIDENCE IN THE ONSET OF LOW CLOUDS WHICH MAY BE AN HOUR
OR TWO TOO EARLY. THE MVFR CIGS ARE THEN EXPECTED TO PERSIST TONIGHT
THRU FRI EVENING.

KBUR...GENERALLY HI CONFIDENCE IN THE 00Z TAF. LOW CLOUDS AND MVFR
CIGS ARE FORECAST TO DEVELOP AT THE AIRFIELD BY 07Z ALTHO THERE IS
MODERATE CONFIDENCE IN THE ONSET OF LOW CLOUDS WHICH MAY BE OFF
PLUS/MINUS AND HOUR OR TWO. THE MVFR CIGS ARE EXPECTED TO
PERSIST LATER TONIGHT THRU EARLY FRI AFTERNOON BEFORE IMPROVING TO
VFR CIGS BY 22Z.


&&

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

&&

$$

PUBLIC...MW
AVIATION...SIRARD
SYNOPSIS...JLD

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