203 
FXUS66 KLOX 202156
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
154 PM PST TUE NOV 20 2012

.SYNOPSIS...

A WEAK STORM SYSTEM WILL BRING POSSIBLE POSSIBLE PRECIPITATION TO 
SANTA BARABARA COUNTY AND NORTHWARD ON WEDNESDAY. THE WINDS WILL BE 
BREEZY IN CORRIDORS AND PASSES TONIGHT INTO THANKSGIVING. A HIGH 
PRESSURE SYSTEM WILL MOVE IN OVER THE WEEKEND WITH LIGHT OFFSHORE 
WINDS AND ABOVE NORMAL TEMPERATURES. A COOLING TREND BEGINS MONDAY 
AS THE HIGH MOVES OUT. 

&&

.SHORT TERM (TODAY-FRI)...A WEAK COLD FRONT WASHED OUT NORTH OF SLO 
COUNTY EARLIER TODAY LEAVING JUST SOME CENTRAL COAST CLOUDS BUT NO 
PRECIP. FURTHER SOUTH CLEAR SKIES TODAY, BUT EXPECTING SOME MARINE 
LYR DEVELOPMENT LATER TONIGHT, MAINLY COASTAL LA COUNTY AND ADJACENT 
WATERS. A SECOND WEAK FRONTAL SYSTEM WILL ARRIVE ALONG THE CENTRAL 
COAST WEDNESDAY MORNING. THIS ONE MAY HAVE A BIT MORE STAYING POWER 
BUT ANY PRECIP THAT DEVELOPS WILL BE EXTREMELY LIGHT AND LIKELY 
CONFINED TO AREAS NORTH OF SBA COUNTY. OTHERWISE WEDNESDAY LOOKS TO 
BE A CARBON COPY OF TODAY. 

BREEZY NORTH WINDS EXPECTED THE NEXT COUPLE OF EVENINGS FOR SRN SBA 
COUNTY BUT SPEEDS SHOULD REMAIN MOSTLY BELOW ADVISORY LEVELS. BEHIND 
THE WEDNESDAY SYSTEM MOIST NORTHEAST FLOW MAY PUSH LOW CLOUDS AND 
FOG OVER FROM THE SRN SAN JOAQUIN VALLEY INTO INTERIOR SLO AND THE 
CUYAMA VALLEY AS WELL THE GRAPEVINE AREA BUT THESE SHOULD BURN OFF 
BY NOON ON THANKSGIVING. BUT TRAVEL OVER THE GRAPEVINE EARLY ON 
THANKSGIVING MAY BE IMPACTED BY SOME DENSE FOG SO PEOPLE TRAVELLING 
INTERSTATE 5 TO/FROM THE CENTRAL VALLEY SHOULD BE PREPARED FOR THAT.

A NICE WARMUP ON TAP FOR ALL AREAS ON THANKSGIVING DAY AND 
ESPECIALLY BLACK FRIDAY AS WEAK OFFSHORE FLOW COMBINES WITH RIDGING 
ALOFT. WARMER VALLEYS SHOULD BREAK INTO THE 80S BY FRIDAY AND EVEN 
COASTAL AREAS SHOULD WARM WELL INTO THE 70S. OFFSHORE WINDS ARE NOT 
EXPECTED TO EXCEED 25 MPH IN MOST AREAS SO ADVISORIES ARE NOT 
ANTICIPATED.

.LONG TERM (SAT-TUE)...ANOTHER WARM ONE SATURDAY WITH TEMPS SIMILAR 
TO FRI. BY SUNDAY AND MONDAY THE RIDGE WILL BREAK DOWN, RESULTING IN 
ONSHORE FLOW RETURNING SO COOLER TEMPS WITH HIGHS BACK TO NEAR 
NORMAL MONDAY. MAY ALSO SEE A RETURN OF MARINE LYR CLOUDS FOR 
SOUTHERN AREAS EARLY NEXT WEEK. PRETTY BIG DIFFERENCES IN THE 12Z 
MODELS BEYOND NEXT TUE, BUT THE MORE CONSISTENT ECMWF PROBABLY THE 
WAY TO GO FOR NOW, MEANING CONTINUED DRY WEATHER WITH A WARMING 
TREND FOR THE LATTER HALF OF NEXT WEEK.

&&

.AVIATION...20/1800Z.

MID/UPPER LEVEL TROUGH OF LOW PRESSURE OVER THE EASTERN PACIFIC WILL 
SHIFT NORTHEAST WHILE A RIDGE OF HIGH PRESSURE OVER THE CENTRAL 
PACIFIC APPROACHES. UPPER LEVEL MODERATE SOUTHWEST WINDS WILL BECOME 
LIGHT TO MODERATE WEST NORTHWEST AND MID LEVEL LIGHT SOUTHWEST WINDS 
WILL BECOME LIGHT NORTHWEST AFTER 21/21Z. WEAK ONSHORE PRESSURE 
GRADIENT THROUGH 21/03Z AND AFTER 21/20Z OTHERWISE WEAK NORTHERLY 
GRADIENT IS EXPECTED. A WEAK MARINE INVERSION WILL PERSIST AND A 
SCATTERED LOW CLOUD FIELD MAY DEVELOP SOUTH OF THE AREA AND PUSH 
NORTH. 

KLAX...CHANCE CIGS 012 BETWEEN 21/14-21/18Z.

KBUR...CURRENT SKY/VSBY CONDITIONS VERY LIKELY.

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

&&

.MARINE...A BROAD AREA OF LOW PRESSURE CENTERED IN THE NORTH CENTRAL 
GULF OF ALASKA AND EXTENDING SOUTH TO 35N OVER THE EASTERN PACIFIC 
HAD GENERATED SEAS TO AROUND 30 FEET LATE MONDAY AFTERNOON. SWELLS 
WITH A 15 SECOND PERIOD ARE EXPECTED TO ARRIVE WEDNESDAY AFTERNOON 
FROM 290-310 DEGREES ALONG THE CENTRAL COAST AND BUILD WEDNESDAY 
NIGHT THROUGH THURSDAY MORNING. THE TIDE WILL RANGE FROM AROUND 4 
FEET IN THE LATE AFTERNOON TO 1 FOOT IN THE LATE WEDNESDAY EVENING 
AND THEN TO AROUND 5 FEET THURSDAY MORNING. SURF WILL LIKELY RISE 
SHARPLY WEDNESDAY WITH BREAKERS POSSIBLY 10 FEET ALONG EXPOSED WEST 
FACING SHORES THURSDAY MORNING. THE SURF WILL VARY THROUGHOUT 
THURSDAY AFTERNOON AND SUBSIDE THURSDAY NIGHT. SURF WILL BUILD ALONG 
THE EXPOSED NORTHWEST FACING SHORES SOUTH OF POINT CONCEPTION 
THURSDAY AND WILL VARY THROUGHOUT THE DAY AS LOW TIDE NEAR 1.5FT IS 
EXPECTED AROUND MIDDAY. STRONG RIP CURRENTS WILL LIKELY EXIST IN THE 
VICINITY OF MARINALLY LARGE BREAKERS. 

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
NONE

&&

$$

PUBLIC...MW
AVIATION/MARINE...30
SYNOPSIS...SETO

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