Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 201217
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
344 AM PST SAT DEC 20 2014

.SYNOPSIS...
A WEAK FRONTAL SYSTEM MAY BRING A FEW SHOWERS TO NORTHERN SECTIONS
TODAY...AND TO THE NORTHERN SLOPES TONIGHT. GUSTY NORTHWEST TO NORTH
WINDS WILL AFFECT PARTS OF THE REGION TONIGHT THROUGH SUNDAY
NIGHT...THEN LOCALLY GUSTY NORTHEAST WINDS WILL AFFECT VENTURA AND
LOS ANGELES COUNTIES MONDAY THROUGH TUESDAY. AN UPPER RIDGE AND
OFFSHORE FLOW WILL BRING A WARMING TREND SUNDAY THROUGH TUESDAY...
WITH TEMPERATURES BECOMING WELL ABOVE NORMAL. GRADUAL COOLING IS
EXPECTED LATE IN THE WEEK AS A TROUGH APPROACHES THE WEST COAST.

&&

.SHORT TERM (TODAY-MON)...PLENTY TO MID AND HIGH LEVEL CLOUDS
PUSHING ACROSS THE AREA THIS MORNING. SOME LOW CLOUDS HAVE DEVELOPED
NEAR THE COAST OF VTU AND L.A. COUNTIES...BUT WERE MOSTLY PATCHY IN
NATURE. CLOUDINESS ASSOCIATED WITH THE SRN END OF A WEAKENING
FRONTAL SYSTEM WERE PUSHING INTO THE CENTRAL COAST EARLY THIS
MORNING. THERE COULD BE A SHOWERS ASSOCIATED WITH THE FRONT IN AREAS
NORTH OF PT CONCEPTION TODAY...MAINLY THIS MORNING.
OTHERWISE...EXPECT PARTLY TO MOSTLY CLOUDY SKIES ACROSS THE REGION
TODAY. MAX TEMPS TODAY WILL BE ON THE COOL SIDE...GENERALLY AT LEAST
A FEW DEGREES BELOW NORMAL.

AS THE TROUGH MOVES EAST OF THE AREA TONIGHT...THE FLOW AT 850 MB
WILL TURN MORE NLY...AS DECENT SUBSIDENCE WILL SPREAD INTO THE
REGION. AT THE SAME TIME...LOW LEVEL N-S GRADIENTS WILL BECOME
INCREASINGLY OFFSHORE. THIS SHOULD BRING SOME GUSTY WINDS TO THE
SANTA YNEZ RANGE AND ADJACENT PORTIONS OF THE S COAST OF SBA
COUNTY...AND TO THE INTERSTATE 5 CORRIDOR TONIGHT. WINDS MAY WELL
REACH LOW END WIND ADVISORY LEVELS IN THESE AREAS. ELSEWHERE...SOME
GUSTY WINDS MAY SPREAD INTO THE VLYS OF NRN AND WRN L.A. COUNTY AND
ERN VTU COUNTY...BUT WINDS THERE SHOULD REMAIN BELOW ADVISORY
LEVELS. NLY FLOW AND SOME RESIDUAL LOW LEVEL MOISTURE SHOULD KEEP
PLENTY OF CLOUDS ON NORTHERN MTNS SLOPES TONIGHT AND SUNDAY
MORNING...AND THERE COULD BE A FEW SHOWERS...MAINLY TONIGHT. SNOW
LEVELS SHOULD BE AROUND 6500 FEET...AND LITTLE IF ANY APPRECIABLE
SNOW ACCUMULATION IS EXPECTED.

AN UPPER RIDGE WILL AMPLIFY OVER THE ERN PACIFIC TONIGHT AND EDGE
INTO THE REGION ON SUNDAY. DECENT OFFSHORE N-S PRESSURE GRADIENTS
WILL CONT TO SUNDAY NIGHT...SO EXPECT SOME GUSTY WINDS TO CONTINUE
ACROSS SRN SBA COUNTY...THROUGH THE I-5 CORRIDOR...AND IN THE VLYS
OF NRN AND WRN L.A. COUNTY AND ERN VTU COUNTY. WITH RISING HEIGHTS
AND THICKNESSES...AND WARMING A H85 AND H95...MAX TEMPS SHOULD BE UP
A FEW DEGREES ON SUNDAY...ESPECIALLY W OF THE MTNS.

THE UPPER RIDGE WILL CONTINUE TO BUILD INTO THE REGION ON MONDAY.
LOW LEVEL FLOW WILL TURN MORE NELY...WHICH SHOULD SHIFT THE FOCUS OF
THE STRONGEST WINDS OUT OF SANTA BARBARA COUNTY BY MON
MORNING...WITH GUSTY...POSSIBLY ADVISORY LEVEL WINDS IN THE MTNS AND
VLYS OF L.A. AND VTU COUNTIES. WITH CONTINUED RISING HEIGHTS
AND WARMING THROUGH 850 MB...EXPECT SEVERAL MORE DEGREES OF WARMING
ON MON...ESPECIALLY W OF THE MTNS...WHERE MAX TEMPS SHOULD RISE TO
WELL ABOVE NORMAL LEVELS. SKIES WILL BE MOSTLY CLEAR SUN NIGHT/MON.

.LONG TERM (TUE-FRI)...A STRONG UPPER RIDGE OVER THE REGION AND
CONTD OFFSHORE FLOW SHOULD MAKE FOR A RATHER WARM DAY ON TUE...WITH
PLENTY OF SUNSHINE...AND DAYTIME TEMPS WELL ABOVE NORMAL...LIKELY
REACHING OR EXCEEDING 80 DEGREES IN THE WARMER LOCATIONS IN THE VLYS
AND INTERIOR COASTAL PLAIN. LOCALLY GUSTY NE WINDS ARE EXPECTED OVER
L.A. AND VTU COUNTIES. THE UPPER HIGH WILL BEGIN TO BREAK DOWN
ON WED...AND OFFSHORE FLOW IS EXPECTED TO WEAKEN. STILL... EXPECT
ANOTHER FAIRLY WARM DAY...ESPECIALLY IN THE VLYS. THE RIDGE WILL
CONTINUE TO BREAK DOWN ON THU...WITH EITHER ZONAL FLOW OR A WEAK
TROUGH ACROSS THE REGION ON FRI DEPENDING UPON WHICH MODEL IS
BELIEVED. THE EC WOULD SUGGEST A SLIGHT CHANCE OF SHOWERS ON THU. NO
MATTER WHAT...A COOLING TREND WILL OCCUR...WITH TEMPS DOWN TO
SLIGHTLY BELOW NORMAL LEVELS BY THE END OF THE WEEK.

&&

.AVIATION...20/1200Z.

GOOD CONFIDENCE THAT MOST TAF SITES WILL REMAIN MVFR OR BETTER
THROUGH THE PERIOD. KPRB...KSBP...KSMX...AND KOXR MAY FALL INTO AND
OUT OF MVFR CIGS THROUGH ABOUT 16Z...BUT THE OVERALL TREND WILL BE
FOR IMPROVING CONDITIONS BY LATE MORNING.

MARINE LAYER AT LAX AT 1740Z IS NONE.

KLAX...GOOD CONFIDENCE IN IFR CONDITIONS THROUGH THE PERIOD. THERE
IS A 10 PERCENT CHANCE OF MVFR CONDITIONS THROUGH 18Z DUE TO CIGS OR
BR/HZ.

KBUR...GOOD CONFIDENCE IN IFR CONDITIONS THROUGH THE PERIOD.

&&

.MARINE...20/400 AM.

GOOD CONFIDENCE IN THE MARINE FORECAST. THE LARGE SWELL WILL PEAK ON
THE CENTRAL COAST AND ACROSS THE OUTER WATERS TODAY...THEN SLOWLY
SUBSIDE THROUGH SUNDAY. HOWEVER...SEAS GREATER THAN 10 FEET MAY
LINGER OVER THE COASTAL WATERS THROUGH MONDAY OR TUESDAY. LARGE
BREAKING WAVES WILL BE POSSIBLE AT AREA HARBORS...ESPECIALLY TODAY.
PLEASE REFER TO THE MARINE WEATHER STATEMENT FOR MORE DETAILS.

WINDS SHOULD REMAIN BELOW SCA THROUGH THIS AFTERNOON...THEN INCREASE
FOR PZZ673 AND PZZ676 THIS EVENING. A GALE WATCH IS IN EFFECT
STARTING SUNDAY AFTERNOON FOR THESE SAME AREA FOR THE POSSIBILITY OF
A LOW END GALE.

&&

.BEACHES...20/330 AM.

LARGE AND POTENTIALLY DAMAGING SURF EVENT FOR THE CENTRAL COAST THIS
WEEKEND. AS OF 3 AM...LEADING EDGE OF LONG PERIOD SWELL (20 SECOND
PERIOD) HAS ARRIVED IN THE COASTAL WATERS AND WILL CONTINUE TO
SPREAD DOWN THE CENTRAL COAST AND BUILD RAPIDLY EARLY THIS MORNING.
SURF STILL EXPECTED TO PEAK TODAY ACROSS THE CENTRAL COAST...WHEN
BREAKERS OF 15 TO 20 FEET WILL BE COMMON ACROSS NORTHWEST FACING
SHORES. LOCALLY HIGHER SETS WILL BE LIKELY AT FAVORED LOCATIONS.
SOME OF THE POTENTIAL IMPACTS FOR THE CENTRAL COAST BEACHES INCLUDE
SIGNIFICANT BEACH EROSION AND STRUCTURE DAMAGE. DUE TO THE UNUSUALLY
HIGH TIDES THIS WEEKEND...THERE WILL ALSO LIKELY BE SOME MINOR
COASTAL FLOODING OF LOW LYING AREAS...NEAR TIMES OF THE MORNING HIGH
TIDE.

WHILE THE SWELL DIRECTION WITH THIS EVENT IS 290-300 DEGREES...THE
PERIOD SHOULD BE SUFFICIENTLY LONG (18 SECONDS) TO ALLOW SOME OF THE
SWELL ENERGY TO REFRACT INTO THE INNER WATERS. AS A RESULT...HIGH
SURF ADVISORIES HAVE BEEN POSTED FOR WEST FACING BEACHES OF LOS
ANGELES AND VENTURA COUNTIES THIS WEEKEND...WHERE SETS OF 5 TO 8
FEET CAN BE EXPECTED. LOCAL MAX SETS TO 10 FEET ARE PROJECTED FOR
VENTURA HARBOR. THE LARGE SURF WILL ALSO BRING DANGEROUS RIP
CURRENTS TO THE REGION THIS WEEKEND.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
FLOOD ADVISORY (SEE LAXFLSLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
HIGH SURF ADVISORY (SEE LAXCFWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).
MARINE WEATHER STATEMENT (SEE LAXMWSLOX).
GALE WATCH (SEE LAXMWWLOX).

&&

$$

PUBLIC...DB
AVIATION/MARINE...SUKUP
SYNOPSIS...DB

WWW.WEATHER.GOV/LOSANGELES





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