Small Craft Advisory 102, NWS Los Angeles, CA

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
205 PM PDT MON AUG 22 2011

.SYNOPSIS...

HIGH PRESSURE WILL BUILD OVER THE AREA...BRINGING ABOVE NORMAL
TEMPERATURES THROUGH THE PERIOD. A WEAKER ONSHORE PATTERN SHOULD
CONFINE THE STRATUS TO THE COASTAL PLAIN.

&&

.SHORT TERM (TODAY-THU)...HIGH CLOUDS CONTINUE TO STREAM INTO THE
AREA FROM THE SOUTH BUT THIS IS HAVING LITTLE IMPACT IN TERMS OF
CONVECTION AS THE AIRMASS JUST ISN'T UNSTABLE ENOUGH AND THE
MOISTURE BELOW 500 MB IS PRETTY MINIMAL. THE CLOUDS DID SLOW DOWN
THE WARMUP A LITTLE TODAY AND HIGHS IN SOME AREAS LIKELY FAILED TO
REACH THEIR POTENTIAL AS A RESULT. WATER VAPOR IMAGERY SHOWS STILL A
FAIR AMOUNT OF MOISTURE TO OUR SOUTH TO MOVE THROUGH TONIGHT AND
EVEN SHOWS A LITTLE ENHANCEMENT THE LAST FEW HOURS NEAR 30N. THE 18Z
NAM INITIALIZED A LITTLE VORT MAX IN THAT AREA BUT DISSIPATES IT
PRETTY RAPIDLY THIS EVENING. CLOSER INSPECTION OF THE SATELLITE
IMAGERY SHOWS NO CIRUCLATION WITH IT AND IT'S LIKELY JUST SOME
SLIGHTLY THICKER HIGH LEVEL CLOUDS THAT WON'T MATERIALIZE INTO
ANYTHING SIGNIFICANT.

SO THE FORECAST THE NEXT FEW DAYS REMAINS PRETTY MUCH AS IT WAS
EARLIER. THE MAIN ADJUSTMENT WAS TO CUT BACK ON THE LOW CLOUDS A BIT
SOUTH OF PT CONCEPTION AS THE NAM SHOWS BOUNDARY LAYER MOISTURE VERY
SLOW TO RETURN TONIGHT AND WHEN IT DOES IT'S MAINLY SOUTH OF OUR
AREA. IF HIGH CLOUDS REMAIN THIN TONIGHT THEN LOW CLOUDS COULD MAKE
A MORE FORMIDABLE RETURN BUT FOR NOW IT APPEARS THAT COASTAL AREAS
OF VENTURA AND LA COUNTY WILL JUST HAVE PATCHY LOW CLOUDS AT BEST.
DECIDED TO CONTINUE THIS THEME THROUGH THURSDAY AS GRADIENTS TREND
SLIGHTLY OFFSHORE AND THE AIRMASS WARMS. TEMPS SHOULD WARM UP MORE
TUESDAY WITH LESS IN THE WAY OF HIGH CLOUDS AND, WEAK OFFSHORE
TRENDS, AND A WARMER AIR MASS OVERALL.

LITTLE CHANGE OR JUST A TAD WARMER WEDNESDAY AS THE WARMING LEVELS
OFF AND GRADIENT TRENDS ARE NEUTRAL.

ON THURSDAY THE UPPER HIGH STRENGTHENS A BIT MORE, PUSHING WARMER
AIR INTO THE AREA AND AGAIN WEAKENING THE ONSHORE FLOW. THIS SHOULD
HELP NUDGE HIGHS UP A FEW MORE DEGREES, PUSHING THE WARMER COASTAL
VALLEYS ABOVE 100 AND SOME ANTELOPE VALLEY LOCATIONS ABOVE 105.

CONVECTIVE POTENTIAL THIS WEEK APPEARS VERY LOW. THE MODELS DO SHOW
850 DEWPOINTS IN THE 3-5 RANGE THE NEXT FEW DAYS, BUT EVEN THIS IS
ON THE LOW SIDE AND BESIDES THE AIR MASS REMAINS TOO STABLE TO
GENERATE ANYTHING. SO THE FORECAST REMAINS THUNDERSTORM FREE.

.LONG TERM (FRI-MON)...LITTLE CHANGE FRI-SAT, THEN SOME WEAKENING OF
THE HIGH PRESSURE OVER CA WILL ALLOW TEMPS TO COOL OFF A FEW DEGREES
SUNDAY AND MONDAY. MARINE LYR WILL REMAIN PATCHY AND CONFINED TO THE
COAST EARLY IN THE PERIOD BUT SHOULD INCREASE IN AREAL COVERAGE LATE
IN THE WEEKEND.

&&

.AVIATION...22/1800Z.

MID/UPPER LEVEL TROUGH OF LOW PRESSURE UPSTREAM WILL PERSIST WHILE A
RIDGE OF HIGH PRESSURE DOWNSTREAM CONTINUES TO SHIFT WEST. MODERATE
UPPER LEVEL SOUTH WINDS AND RELATIVELY MOIST WILL PREVAIL WHILE
LIGHT TO MODERATE MID LEVEL SOUTH WINDS BECOME LIGHT AND VARIABLE
AFTER 23/04Z. DISORGANIZED MARINE LAYER TOP RANGED FROM .6-1.6KFT
THIS MORNING AND WILL DIFFER BY MINUS .3KFT TUESDAY MORNING. WEAK TO
MODERATE ONSHORE PRESSURE GRADIENT BETWEEN 22/20-23/03Z AND AFTER
23/20Z...OTHERWISE A WEAK GRADIENT.

KLAX...CHANCE SCT 008 WITH VSBY 4SM HZ BETWEEN 23/10-23/16Z.

KBUR...VERY LIKELY SCT-BKN 200 THROUGH 23/03Z THEN SCT 250
THEREAFTER.

VIRTUALLY CERTAIN - 95-100%
VERY LIKELY       - 80-95%
LIKELY            - 60-80%
CHANCE            - 30-60%
VERY UNLIKELY     - 20% OR LESS

&&

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

&&

PUBLIC...WOFFORD
AVIATION...30
SYNOPSIS...BARTLING

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