Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 180401
AFDLOX

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

.SYNOPSIS...
A LOW WILL BRING DRIZZLE FOR TONIGHT INTO THE MORNING FOR THE COAST
AND VALLEYS. THERE WILL ALSO BE A SLIGHT CHANCE OF AFTERNOON SHOWERS
OR THUNDERSTORMS ON FRIDAY IN THE SANTA BARBARA...VENTURA AND LOS
ANGELES COUNTY MOUNTAINS. HIGH PRESSURE WILL BRING ABOVE NORMAL
AFTERNOON TEMPERATURES ON SUNDAY. AN UPPER LEVEL TROUGH OF LOW
PRESSURE WILL BRING MORE CLOUDS...HIGHER HUMIDITIES AND BELOW NORMAL
TEMPERATURES BY MIDWEEK.

&&

.SHORT TERM (TONIGHT-SUN)...PLENTY OF HI LEVEL MOISTURE COVERED THE
FORECAST AREA THIS EVENING WITH MOSTLY CLOUDY SKIES. THERE WAS ALSO
EXTENSIVE LOW LEVEL MOISTURE WITH LOW CLOUDS MOVING INTO MANY
COASTAL AND VALLEY AREAS. THE LOW CLOUDS AND DEEPENING MARINE LAYER
WILL COVER THE COAST AND VALLEYS OVERNIGHT AND ALSO MOVE TO THE
LOWER COASTAL SLOPES. PATCHY DRIZZLE IS EXPECTED AS WELL FOR THE
COAST/VLYS/LOWER CSTL SLOPES S OF POINT CONCEPTION OVERNIGHT.

A WEAK UPPER LEVEL LOW PRESSURE AREA JUST SW OF THE COASTAL WATERS
THIS EVENING WILL MOVE TOWARD THE COAST OVERNIGHT THEN GRADUALLY
MOVE E AND INLAND ON FRI AND FRI NIGHT. UPPER LEVEL RIDGING SHOULD
BUILD INTO SRN CA LATE SAT THRU SUN. THE UPPER LOW IS FORECAST TO
BRING GOOD INSTABILITY INTO THE AREA ON FRI AND COMBINED WITH SOME
INCREASE IN MID LEVEL MOISTURE HAVE INTRODUCED A SLIGHT CHANCE OF
THUNDERSTORMS TO THE L.A./VTU/SBA COUNTY MTNS FRI AFTERNOON AND
EVENING. THE BEST CHANCE OF CONVECTION WILL BE OVER THE VTU COUNTY
MTNS AND THE SAN GABRIEL MTNS...ESPECIALLY IF THERE ARE BREAKS IN
THE HI CLOUD COVER. OTHERWISE...PATCHY DRIZZLE WILL PERSIST IN THE
MORNING FOR THE COAST/VLYS/CSTL SLOPES OF VTU/L.A. COUNTIES. ONLY
PARTIAL AFTERNOON CLEARING AT BEST IS EXPECTED FOR MOST COAST AND
VLYS ON FRI. MORE LOW CLOUDS ARE EXPECTED FRI NIGHT AND SAT
MORNING...AND SAT NIGHT INTO SUN MORNING MAINLY FOR THE COAST AND
SOME ADJACENT VLYS. OTHERWISE...MOSTLY CLEAR SKIES SHOULD PREVAIL
OVER THE AREA SAT AND SUN. TEMPS ARE FORECAST TO BE NEAR NORMAL FOR
MOST AREAS ON FRI THEN WARM TO SIGNIFICANTLY ABOVE NORMAL ESPECIALLY
INLAND BY SUN.

***FROM PREVIOUS DISCUSSION***

.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...SIRARD/MW
AVIATION...SIRARD
SYNOPSIS...SETO

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