Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 310252
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
750 PM PDT SUN AUG 30 2015

.SYNOPSIS...

A BROAD TROUGH OF LOW PRESSURE WILL PERSIST OVER THE WEST COAST THIS
WEEK...BRINGING BELOW NORMAL TEMPERATURES AND AN INCREASE IN NIGHT
THROUGH MORNING LOW CLOUDS AND FOG FOR AREAS WEST OF THE MOUNTAINS.
SLIGHT WARMING IS POSSIBLE NEXT WEEKEND AS THE TROUGH OF LOW
PRESSURE SHIFTS EAST AND ONSHORE FLOW WEAKENS.

&&

.SHORT TERM (TODAY-WED)...EVENING UPDATE... LATEST SATELLITE IMAGERY
INDICATED A SWATH OF HIGH CLOUDS MOVING ACROSS MOST AREAS SOUTH OF
SAN LUIS OBISPO COUNTY THIS EVENING. THIS WILL BE SHORT LIVED AS
SKIES BECOME MOSTLY CLEAR OVERNIGHT. A WIND ADVISORY REMAINS IN
EFFECT FOR THE SANTA BARBARA COUNTY SOUTH COAST AND ADJACENT
MOUNTAINS THROUGH THE OVERNIGHT HOURS...WITH THE STRONGEST WINDS
OCCURRING IN THE PASSES AND CANYONS BETWEEN GAVIOTA AND GOLETA. THE
TEMPERATURES ACROSS THE SANTA BARBARA COAST ARE MUCH COOLER THAN
YESTERDAY AT THIS TIME. IN FACT A SOUTHERLY WIND COMPONENT OVER THE
CITY OF SANTA BARBARA HAS KEPT HIGH TEMPS MUCH COOLER.
OVERALL...HIGH TEMPS CONTINUED TO TREND DOWN THIS AFTERNOON AND
RANGED FROM A COUPLE DEGREES TO -12 DEGREES IN SOME VALLEY
LOCATIONS.

SYNOPTICALLY...A DEEP  UPPER LEVEL TROUGH ASSOCIATED WITH A STRONG
UPPER LOW IN THE GULF OF ALASKA WILL CONTINUE TO DEEPEN AND PERSIST
OVER THE REGION THROUGH THE FOLLOWING WEEK. EXPECT HIGH TEMPS TO
CONTINUE TO COOL OVER THE NEXT SEVERAL DAYS WITH HIGH TEMPS A FEW
DEGREES BELOW NORMAL OVERALL. THE LATEST AMDAR SOUNDING NEAR LAX
INDICATED THE MARINE LAYER DEPTH AROUND 1300 FT DEEP WITH A
RELATIVELY STRONG INVERSION ABOVE. EXPECTING THE MARINE LAYER TO
DEEP TO AT LEAST 1500 FT BY MORNING. MODELS ARE SUGGESTING AN EDDY
WILL BEGIN TO DEVELOP OVER THE SO CAL BIGHT TONIGHT. LATEST FOG
PRODUCT IMAGERY DOES SHOW A SMALL SPECK OF STRATUS OVER THE ORANGE
COUNTY COAST. BASED ON THE EDDY AND THE UPPER TROUGH MOVING CLOSER
TO THE REGION...EXPECTING LOW CLOUDS TO DEVELOP LATER TONIGHT. NOT
THAT CONFIDENT IT WILL BECOME WIDESPREAD...BUT THERE SHOULD BE LOW
CLOUDS AFFECTING THE LA COUNTY COAST AND POSSIBLY THE SAN GABRIEL
VALLEY AFTER MIDNIGHT WITH THE MARINE LAYER DEPTH INCREASING...IN
PART DUE TO THE EDDY CIRCULATION EXPECTED TO INCREASE. AS FAR AS THE
CENTRAL COAST...ITS A TOUGH CALL. I SUSPECT BY LATE TONIGHT SOME
PATCHY LOW CLOUDS WILL DEVELOP NEAR LOMPOC AND SANTA MARIA...WITH
MORE WIDESPREAD LOW CLOUDS MOVING IN ACROSS MUCH OF THE CENTRAL
COAST AND SANTA YNEZ VALLEY TOMORROW NIGHT.

FOR MONDAY...LOOKS LIKE MOST VALLEYS WILL SEE HIGH TEMPS REACH THE
MID TO UPPER 80S WITH A COUPLE OF THE WARMEST VALLEY LOCATIONS
POSSIBLY REACHING 90. THE LA BASIN WILL BE MUCH MORE MILDER AS HIGH
TEMPS FOR DOWNTOWN L.A. ARE ONLY EXPECTED TO REACH THE LOWER TO MID
80S...WITH IMMEDIATE COASTAL AREAS IN THE 70S. THERE WILL BE SOME
MODEST COOLING FOR TUESDAY WITH SIMILAR NIGHT THROUGH MORNING LOW
CLOUDS FOR COAST AND COASTAL VALLEYS. ALSO...THERE SHOULD BE SOME
HIGH CLOUDS THAT MOVE INTO THE AREA ASSOCIATED WITH A WEAK VORT THAT
THE NAM WRF PICKS UP ON FOR TUESDAY AFTERNOON/NIGHT. OTHERWISE A
QUIET PATTERN AHEAD MOST OF THIS WEEK. EXPECT NIGHT THROUGH MORNING
LOW CLOUDS TO CONTINUE THROUGH THE SHORT PERIOD FOR COAST AND
COASTAL VALEYS.

***FROM PREVIOUS DISCUSSION***

.LONG TERM (THU-SUN)...MADE MINOR CHANGES THROUGH THE PERIOD.
GUIDANCE WAS SIMILAR WITH PREVIOUS RUNS AND A MEAN LONG WAVE TROUGH
CENTERED OVER THE WEST COAST WILL BECOME LESS AMPLIFIED WHILE
GRADUALLY SHIFTING EAST THROUGH THE PERIOD. A SUBTROPICAL RIDGE OF
HIGH PRESSURE IS EXPECTED TO BUILD NORTH OVER THE AREA BY THE END OF
THE PERIOD. ANALOG GUIDANCE INDICATED SUBTROPICAL MOISTURE MOVING
NORTH WITH THE SUBTROPICAL RIDGE BUT THE OPERATIONAL GUIDANCE
INDICATED DRIER SOUTHWEST WINDS UPSTREAM AND OVER THE AREA. HAVE
INCLUDED CLIMATOLOGY POPS AT THIS TIME OVER THE ENTIRE AREA. MINOR
TEMPERATURES CHANGES ARE EXPECTED THURSDAY THROUGH FRIDAY THEN A
SLIGHT WARMING TREND IS EXPECTED SATURDAY THROUGH SUNDAY.
TEMPERATURES WILL LIKELY RANGE BETWEEN 2 TO 5 DEGREES BELOW SEASONAL
NORMAL THROUGH THE PERIOD.

&&

.AVIATION...30/2340Z

AT 2330Z...THE MARINE INVERSION AT KLAX WAS AROUND 1200 FT DEEP. THE
TOP OF THE INVERSION WAS AROUND 3000 FEET WITH A TEMPERATURE OF 25
DEGREES CELSIUS.

N OF POINT CONCEPTION...MODERATE CONFIDENCE THAT SKIES WILL REMAIN
VFR OR LIFR VISBYS AFTER 08Z THIS EVENING. THERE WILL BE  A 30
PERCENT CHANCE THAT LIFR/LIFR CIGS COULD DEVELOP AROUND THE KSMX
AREA BETWEEN 09Z-15Z. 30 PERCENT CHANCE FOR LIFR CIGS FOR KPRB AS
WELL AFTER 11Z-16Z.

S OF POINT CONCEPTION...MODERATE CONFIDENCE WITH LIFR OR LOW MVFR
CIGS DEVELOPING AROUND KLGB AND KLAX AFTER 09Z. 30 PERCENT CHANCE
THAT CIGS WILL NOT DEVELOP. SLIGHTLY LOWER CONFIDENCE THAT CIGS WILL
DEVELOP ACROSS THE VENTURA COASTAL TAF SITES.

KLAX...MODERATE CONFIDENCE IN 00Z TAF. THERE IS A 30 PERCENT CHANCE
OF VFR CONDITIONS CONTINUING AFTER 09Z TONIGHT THROUGH MONDAY
MORNING.

KBUR...GOOD CONFIDENCE IN THE 00Z TAF. VFR CONDITIONS ARE EXPECTED
THROUGH MONDAY MORNING. THERE WILL BE A 20 PERCENT CHANCE OFR
LIFR/IFR CIGS TO DEVELOP BETWEEN 11Z-15Z MONDAY MORNING.

&&

.MARINE...30/200 PM

OUTER WATERS...GOOD CONFIDENCE THAT SMALL CRAFT ADVISORY LEVEL WINDS
WILL INCREASE TO GALE FORCE (NORTH OF SAN NICOLAS ISLAND) DURING
THIS AFTERNOON AND LAST THROUGH THE NIGHT. SMALL CRAFT ADVISORY
LEVEL WINDS AND GUSTS WILL LIKELY PERSIST THROUGH MONDAY.

INNER WATERS...GOOD CONFIDENCE IN THE INNER WATERS FORECAST. THERE
WILL BE SMALL CRAFT GUSTS ACROSS THE WESTERN THIRD OF THE SBA CHANNEL
AND IN PORTIONS OF THE INNER WATERS ADJACENT TO THE CENTRAL COAST LATER
THIS AFTERNOON THROUGH TONIGHT.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY (SEE LAXNPWLOX).
GALE WARNING (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
HIGH RIP CURRENT RISK (SEE LAXNPWLOX)

&&

$$

PUBLIC...KAPLAN/30
AVIATION...KAPLAN
MARINE...SWEET
SYNOPSIS...SUKUP

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