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000
FXUS66 KLOX 260319
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
800 PM PDT SAT MAY 25 2013

.SYNOPSIS...

LOW PRESSURE TO THE NORTH WILL RESULT IN SLIGHTLY BELOW NORMAL
TEMPERATURES THROUGH EARLY NEXT WEEK...ALONG WITH NIGHT THROUGH
MORNING LOW CLOUDS AND PATCHY FOG FOR THE COASTAL PLAIN AND VALLEYS.
A TROUGH OF LOW PRESSURE WILL MOVE THROUGH THE AREA MONDAY NIGHT AND
TUESDAY...BRINGING A CHANCE OF SHOWERS AS WELL AS GUSTY NORTH TO
NORTHWEST WINDS. A WARMING TREND IS THEN EXPECTED LATE NEXT WEEK.

&&

.SHORT TERM (TONIGHT-TUE)...FORECAST LOOKS TO BE IN GOOD SHAPE THIS
EVENING. MADE SLIGHT ADJUSTMENT TO BUMP UP WIND GUSTS FOR THE
CENTRAL COAST THE NEXT FEW AFTERNOON AND EVENING HOURS (SUN-TUE)
HIGH TEMPS WERE JUST ABOUT THE SAME FOR THE MOST PART TODAY COMPARED
TO YESTERDAY. A VERY PERSISTENT UPPER TROUGH WILL LINGER OVER THE
WEST COAST KEEPING TEMPERATURES RATHER MILD FOR THIS TIME OF YEAR.

LATEST NAM-WRF CROSS SECTION CONTINUES TO SHOW THE MARINE LAYER
DEEPENING TO AROUND 2500 FT LATE TONIGHT AND BECOMING MORE
WIDESPREAD BY SUNDAY MORNING. LATEST AMDAR SOUNDING INDICATED A WEAK
INVERSION AROUND 1500 FT THIS EVENING NEAR LAX. SO LOW CLOUDS MIGHT
BE A TAD DELAYED PUSHING IN FROM THE SOUTH...BUT SHOULD HAVE NO
PROBLEM FILLING TO THE COASTAL SLOPES OF LA/VTU COUNTIES. THE MARINE
LAYER DEPTH WILL NOT BE QUITE AS DEEP ACROSS THE CENTRAL COAST...BUT
SHOULD FILL IN THIS EVENING AND INTO PORTIONS OF THE INTERIOR
VALLEYS INCLUDING PASO ROBLES LATE TONIGHT OR EARLY SUNDAY MORNING.

EXPECT SOME COOLING AROUND THE COASTAL AREAS TOMORROW AS LOW CLOUDS
SHOULD BE A BIT MORE STUBBORN TO BURN OFF...WHILE INLAND AREAS
SHOULD BE AROUND THE SAME OR A DEGREE OR TWO WARMER AS HEIGHTS ARE A
TAD HIGHER. WITH THE ONSHORE GRADIENT BETWEEN LAX-DAG EXPECTED TO BE
AROUND +9 MB TOMORROW. GUSTY SW WINDS SHOULD STRENGTHEN ACROSS THE
ANTELOPE VALLEY. A WIND ADVISORY IS IN PLACE FOR NOON TOMORROW
THROUGH EARLY SUNDAY MORNING. EXPECT GUSTS TO 45 MPH...WITH LOCALLY
HIGHER GUSTS AROUND LAKE PALMDALE. SUNDOWNER WINDS WILL ALSO DEVELOP
ACROSS THE SANTA BARBARA COUNTY MOUNTAINS AND WIND PRONE PASSES AND
CANYONS OF THE SANTA BARBARA SOUTH COAST TOMORROW LATE AFTERNOON AND
CONTINUE THROUGH THE EVENING HOURS. WINDS WILL ALSO BE GUSTY ACROSS
THE CENTRAL COAST TOMORROW...BUT NOT AS STRONG AS THE SBA SOUTH
COAST. WIND ADVISORY ALREADY IN PLACE FOR THE SBA SOUTH COAST
TOMORROW AS WELL.

***FROM PREVIOUS DISCUSSION***

ON MONDAY...A STRONGER LOW PRESSURE SYSTEM DROPS INTO THE PACIFIC
NORTHWEST ACCOMPANIED BY A 100+KT NORTHWESTERLY JET. CLOUDS WILL
START TO INCREASE ACROSS ALL AREAS MONDAY AFTERNOON AND WINDS WILL
BECOME GUSTY FOR MANY AREAS...ESPECIALLY THE MOUNTAINS AND DESERTS.
WOULD EXPECT SOLID WIND ADVISORIES FOR THESE AREAS ON MONDAY AND
TUESDAY. THE FRONT ASSOCIATED WITH THIS SYSTEM WEAKENS AS IT
APPROACHES THE CENTRAL COAST MONDAY NIGHT/TUESDAY MORNING...BUT WILL
CONTINUE WITH A CHANCE OF SHOWERS NORTH OF PT CONCEPTION. THE OTHER
AREAS WITH THE HIGHEST RISK OF SHOWERS WILL BE THE NORTH SLOPE OF
THE MOUNTAINS. IT WILL BE HARD TO GET MUCH OF ANYTHING RAIN-WISE FOR
THE SOUTH COASTAL SLOPES AND COASTS OF VENTURA AND LOS ANGELES
COUNTIES DUE TO THE STRONG NORTHWEST FLOW. WOULD EXPECT DECREASING
CLOUD COVER IN THE WAKE OF THIS SYSTEM BY TUESDAY AFTERNOON.

.LONG TERM (WED-SAT)...CONTINUING WINDY CONDITIONS ON WEDNESDAY BUT
REMOVED ANY MENTION OF SHOWERS BY THEN. TEMPERATURES WILL REMAIN
BELOW NORMAL ON WEDNESDAY. A HIGH PRESSURE RIDGE WILL BUILD INTO THE
WEST COAST STARTING THURSDAY AND LINGER THROUGH SATURDAY. A DRY
OFFSHORE FLOW WILL SQUASH ANY LOW CLOUD DEVELOPMENT AND EXPECT
TEMPERATURES TO PUSH WELL INTO THE 80S AND 90S LATE IN THE WEEK FOR
INLAND VALLEYS. THE ECMWF MODEL HINTS AT SOME BACKBUILDING OF THE
CENTRAL STATES TROUGH BY SATURDAY WHICH WOULD DROP HEIGHTS
SOME...BUT GFS STAYS MORE PROGRESSIVE AND ON THE WARMER SIDE.

&&

.AVIATION...26/0020Z...

MODERATE CONFIDENCE IN 00Z TAFS...A DEEP MARINE LAYER EXPECTED TO
PUSH IN FROM SOUTH TO NORTH DUE TO THE EDDY AND BRING SOMEWHAT MORE
WIDESPREAD STRATUS CLOUDS TO THE COAST AND VALLEYS OVERNIGHT INTO
SUNDAY MORNING. EXPECT KSBA TO REMAIN CLEAR OVERNIGHT. THERE WILL BE
A 20 PERCENT CHANCE FOR CIGS TO DEVELOP EARLY SUNDAY MORNING AT KSBA.

EXPECT IFR/MVFR CIGS TO FORM AFTER 07-08Z TONIGHT FOR THE CENTRAL
COAST SITES AND KPRB A FEW HOURS LATER...ALTHOUGH LOWER CONFIDENCE
IN THE TIMING AND HEIGHT OF LOW CLOUDS FOR KPRB.

S OF PT CONCEPTION...EXPECT FAIRLY SIMILAR MARINE LAYER DEPTH AND
COVERAGE...BUT PUSHING FURTHER NORTH ALONG THE VENTURA COAST TO
KOXR. THE TIMING OF STRATUS CLOUDS ARRIVING AT THE AIRFIELDS MAY
DIFFER UP TO 2 HRS FROM TAF TIMES. BUT GOOD CONFIDENCE FOR LOW
CLOUDS TO LINGER MOST OF THE DAY ALONG THE COAST...ESPECIALLY ACROSS
VENTURA COUNTY. NORTHERLY WINDS ACROSS THE SBA COUNTY SOUTH COAST
SHOULD LEAVE SKIES WITH VFR CONDS.

KLAX...MODERATE CONFIDENCE IN 00Z TAF. THE MODERATE CONFIDENCE IS
FOR TIMING OF STRATUS RETURN TONIGHT...WHICH MAY DIFFER UP TO 2 HRS
FROM TAF TIME OF 07Z. BETTER CONFIDENCE THAT MVFR CIGS WILL LINGER
INTO THE AFTERNOON HOURS. 30 PERCENT CHANCE FOR LOW CLOUDS TO LINGER
THE ENTIRE DAY.

KBUR...MODERATE CONFIDENCE IN 00Z TAF. THE TIMING OF MVFR CIGS
RETURNING AND SCATTERING OUT TOMORROW IS A BIT UNCERTAIN. BUT
SHOULD LINGER A FEW HOURS LONGER.

&&

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

&&

$$

PUBLIC...KAPLAN/BOLDT
AVIATION...KAPLAN
SYNOPSIS...SETO

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