000
FXUS66 KLOX 211003
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
303 AM PDT SUN SEP 21 2008

.SHORT TERM (TODAY-WEDNESDAY)...MARINE LAYER IS PATCHY THIS
MORNING WITH WEAK INVERSION IN PLACE AND MARINE LAYER DEPTH
AROUND 1500 FEET. FORECAST HAS INCREASED MARINE LAYER PRESENCE IN
SAN FERNANDO VALLEYS BUT DECREASE STRATUS DEVELOPMENT IN THE
SALINAS RIVER VALLEY. OTHERWISE...PATCHY FORECAST SEEMS TO WORK
OUT FOR THIS MORNING WITH WEAK INVERSION IN PLACE. TEMPERATURES
WERE WARMED SLIGHTLY WITH WEAK MARINE INVERSION IN PLACE AND A
SLIGHT OFFSHORE TREND OCCURRING THIS MORNING.

GOOD AGREEMENT BETWEEN BOTH NAM AND GFS SOLUTIONS IN INDICATING
LITTLE CHANGE IN THE MARINE LAYER FOR TONIGHT AND MONDAY.
1000-500 MB THICKNESSES STAY ABOUT THE SAME IN BOTH MODELS. AREAL
COVERAGES SHOULD BE SIMILAR WITH MAYBE SLIGHT THICKENING IN THE
MARINE LAYER SOUTH OF POINT CONCEPTION. THIS WILL BE DUE TO AN
EDDY CIRCULATION OVER THE INNER WATERS.

TEMPERATURES COULD BE MIXED FOR MONDAY. 950 MB TEMPERATURES
WARM OVER THE AREA...BUT THICKNESSES STAY AROUND THE SAME.
SURFACE GRADIENTS TREND MORE ONSHORE SOUTH OF POINT CONCEPTION
AND TREND OFFSHORE NORTH OF POINT CONCEPTION. WITH WARMER SEA
SURFACE TEMPERATURES IN PLACE OVER THE INNER WATERS AND AT THE
BEACHES...FORECAST TRENDS SLIGHT WARMER...BUT A WELL-DEVELOPED
EDDY CIRCULATION COULD PUT THE DAMPER ON THE TREND.

1000-500 MB THICKNESSES AND 950 MB TEMPERATURES TREND UPWARD FOR
MIDWEEK WITH NEUTRAL TO OFFSHORE TRENDING SURFACE GRADIENTS.
MARINE LAYER WILL REMAIN OVER THE COASTAL SECTION...BUT A
DECREASING INFLUENCE IN COVERAGE AND DEPTH WILL LIKELY BRING
WARMER TEMPERATURES TO THE AREA FOR MIDWEEK.

.LONG TERM (THURSDAY-SATURDAY)...SOUTH TO SOUTHWEST FLOW ALOFT
WILL LIKELY REDEVELOP FOR LATE WEEK BRINGING AN INCREASE IN
MARINE LAYER MOISTURE. GFS SOLUTIONS COULD DEVELOP A EDDY
CIRCULATION OVER THE INNER WATERS WITH SOME LOCAL DRIZZLE
POSSIBLE...BUT ECMWF SOLUTIONS DOWNPLAY THE SCENARIO. AT THE VERY
LEAST...A COOLING TREND SHOULD DEVELOP FOR LATE WEEK AND INTO THE
WEEKEND.

&&

.AVIATION...21/0530Z.

MARINE LAYER ABOUT 1400 DEEP AND CAPPED BY A VERY WEAK INVERSION. A
WEAK EDDY WILL SPIN UP TONIGHT AND CIGS WILL LIKELY FORM FROM KLGB
TO KOXR AND CANNOT RULE OUT GETTING INTO KSBA (IN FACT THIS COULD BE
ONE OF THOSE TIMES WHERE KSBA GETS THE CIGS AFTER SUNRISE. CLOUDS
WILL BE MORE PATCHY IN THE VLYS. DUE TO WEAK INVERSION BURN OFF
SHOULD OCCUR NEAR MID MORNING.

KLAX...GOOD CONFIDENCE IN TAF CIGS WILL LIKELY ARRIVE WITH IN ONE
HOUR OF FCST TIME AND BURN OFF TIME IS ALSO LIKELY WITH THE SAME ONE
HOUR BLOCK.

KBUR...ONLY FAIR CONFIDENCE IN TAF. THERE IS A 40 PERCENT CHANCE OF
IFR CIGS AFTER 11Z. IF CIGS DO FORM THEY SHOULD DISSIPATE BY 16Z.

&&

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

&&

$$

PUBLIC...HALL
AVIATION...ASR

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