Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 191027
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
225 AM PST FRI DEC 19 2014

...UPDATED MARINE SECTION...

.SYNOPSIS...

A WEAK COLD FRONT WILL BRING THE CHANCE OF SOME LIGHT SHOWERS TO THE
AREA TODAY AND TONIGHT. FROM SATURDAY THROUGH EARLY NEXT WEEK...HIGH
PRESSURE WILL GRADUALLY BUILD OVER THE AREA. THIS WILL BRING WARMING
TEMPERATURES AND THE POTENTIAL FOR SOME GUSTY NORTH TO NORTHEAST
WINDS AT TIMES THROUGH TUESDAY. FOR CHRISTMAS EVE AND CHRISTMAS
DAY...COOLER CONDITIONS ARE ANTICIPATED AS A SYSTEM DIVES INTO THE
GREAT BASIN.

&&

.SHORT TERM (TODAY-SUN)...OVERALL...00Z MODELS IN GOOD SYNOPTIC
AGREEMENT THRU THE PERIOD. AT UPPER LEVELS...WEAK TROUGH WILL ZIP
ACROSS CENTRAL/SOUTHERN CALIFORNIA TODAY...WITH A RIDGE BUILDING IN
FROM THE SOUTHWEST SATURDAY/SUNDAY. NEAR THE SURFACE...WEAK FRONT
WILL SWEEP ACROSS THE AREA TODAY/TONIGHT...THEN NORTHWEST/NORTH FLOW
WILL DEVELOP SATURDAY/SUNDAY.

FORECAST-WISE...WILL EXPECT A GENERALLY MOSTLY CLOUDY DAY TODAY AND
TONIGHT AS WEAK FRONTAL SYSTEM MOVES THRU THE AREA. THIS FRONT DOES
NOT HAVE MUCH "PUNCH" TO IT...BUT STILL SHOULD BE ABLE TO GENERATE
SOME SHOWER ACTIVITY FOR THE AREA. WITH MORNING FORECAST...WILL KEEP
WITH CHANCE/SLIGHT CHANCE POPS FOR SAN LUIS OBISPO/SANTA BARBARA
COUNTIES TODAY/TONIGHT...AND A SLIGHT CHANCE OF SHOWERS LATE THIS
AFTERNOON/TONIGHT FOR VENTURA/LOS ANGELES COUNTIES. OVERALL...RAIN
AMOUNTS SHOULD GENERALLY BE LESS THAN ONE TENTH OF AN INCH...BUT
THE USUAL RAIN MAGNET IN NORTHWEST SAN LUIS OBISPO COUNTY WILL
LIKELY RECEIVE A BIT MORE.

FOR SATURDAY/SUNDAY...THE WEATHER WILL BE DRY AS THE UPPER RIDGE
BUILDS IN FROM THE SOUTHWEST. SKIES WILL TURN PARTLY CLOUDY ON
SATURDAY THEN MOSTLY CLEAR ON SUNDAY. AS FOR TEMPERATURES...WILL
EXPECT A WARMING TREND AS OFFSHORE GRADIENTS STRENGTHEN...ESPECIALLY
ON SUNDAY. SO...BY SUNDAY...MOST COASTAL/VALLEY AREAS WILL BE
COMFORTABLY IN THE UPPER 60S TO MID 70S.

AS FOR WINDS...WITH NORTHERLY FLOW DEVELOPING ON SATURDAY...THERE
COULD BE SOME GUSTY WINDS LATE SATURDAY AFTERNOON/SATURDAY NIGHT
ACROSS THE I-5 CORRIDOR AND SANTA YNEZ RANGE. LOW END ADVISORY LEVEL
WINDS ARE DEFINITELY WITHIN THE REALM OF POSSIBILITY.

.LONG TERM (MON-THU)...FOR THE EXTENDED...MODELS CONTINUE TO EXHIBIT
GOOD SYNOPTIC AGREEMENT. AT UPPER LEVELS...RIDGE WILL PEAK IN
STRENGTH ON MONDAY...WEAKEN SLIGHTLY ON TUESDAY...THEN AN INSIDE
SLIDER WILL FLATTEN THE RIDGE WEDNESDAY/THURSDAY. NEAR THE SURFACE
OFFSHORE FLOW WILL CONTINUE TO INCREASE THROUGH TUESDAY...THEN SHIFT
BACK TO AN ONSHORE FLOW WEDNESDAY/THURSDAY.

FORECAST-WISE...MONDAY/TUESDAY LOOK TO BE WARM AND DRY DAYS DUE TO
COMBO OF UPPER RIDGE AND OFFSHORE FLOW. TEMPERATURES WILL PEAK ON
TUESDAY WITH WIDESPREAD 70S TO LOWER 80S ACROSS THE COASTS AND
VALLEYS. AS FOR WINDS...THERE WILL BE SOME GUSTY OFFSHORE WINDS ACROSS
THE AREA...ESPECIALLY ON TUESDAY. AT THIS TIME...THERE IS THE
POTENTIAL FOR SOME LOW-END ADVISORY-LEVEL SANTA ANA WINDS ON TUESDAY.

FOR WEDNESDAY/THURDAY...THINGS WILL CHANGE NOTICEABLY AS WEST TO
NORTHWEST FLOW RETURNS TO THE AREA. AFTERNOON TEMPERATURES WILL SHOW
A COOLING TREND...FALLING INTO THE 60S BY CHRISTMAS DAY. AT THIS
TIME...THE FORECAST REMAINS DRY...BUT WOULD NOT BE SHOCKED TO SEE
THE POSSIBILITY OF SOME INLAND SHOWERS ON THURSDAY AS THE INSIDE
SLIDER MOVES INTO THE GREAT BASIN (IN FACT THE ECMWF DOES SHOW SOME
LIGHT PRECIP). SO...THIS SITUATION WILL BE WATCHED OVER THE NEXT FEW
DAYS.

&&

.AVIATION...19/0600Z.

MARINE LAYER AT LAX AT 0600Z IS NONE.

WITH NO MARINE LAYER INVERSION AND MID-HIGH CLOUDS MOVING THROUGH
THE AREA TONIGHT...CONFIDENCE IS LOW TO MODERATE FOR MUCH OF THE
AREA. LOW CONFIDENCE FOR TAF SITES IN SLO AND SBA COUNTY. MODERATE
CONFIDENCE ELSEWHERE. THERE IS A 40 PERCENT CHANCE THAT LIFR
CONDITIONS WILL NOT DEVELOP AT KPRB TONIGHT. ALSO A 40 PERCENT
CHANCE THAT KSBP AND KSMX WILL NOT FALL INTO THE LIFR CATEGORY.
THERE IS A 20-40 PERCENT CHANCE THAT COASTAL SITES SOUTH OF POINT
CONCEPTION WILL HAVE MVFR CONDITIONS FROM 08-18Z...WITH KSBA AND
KOXR HAVING THE BEST CHANCES. A WEAK DISTURBANCE WITH ISOLATED
SHOWERS WILL MOVE ACROSS THE AREA FRIDAY AFTERNOON. BEST CHANCE FOR
SHOWERS WILL BE IN SLO AND SBA COUNTY. THERE IS 20-30 PERCENT CHANCE
OF MVFR CONDITIONS AT MOST SITES TOMORROW AFTERNOON.

KLAX...MODERATE CONFIDENCE IN THE 06Z TAF. THERE IS A 20 PERCENT
CHANCE OF MVFR CONDITIONS AFTER 12Z.

KBUR...MODERATE CONFIDENCE IN 06Z TAF. THERE IS A 20 PERCENT CHANCE
OF MVFR CONDITIONS AFTER 18Z.

&&

.MARINE...19/230 AM.

HIGH CONFIDENCE THAT WINDS WILL REMAIN LIGHT THROUGH SATURDAY
MORNING...FOLLOWED BY A GOOD CHANCE OF SCA WINDS FOR THE OUTER
WATERS AND POSSIBLY IN THE VICINITY OF THE CHANNEL ISLANDS BY
SATURDAY EVENING. THE SCA FOR HAZARDOUS SEAS FOR THE CENTRAL COAST
AND THE OUTER WATERS BEGINS THIS EVENING AND WAS EXTENDED THROUGH
LATE SATURDAY NIGHT...BUT COMBINED SEAS IN THESE AREAS MAY REMAIN
ABOVE 10 FT THROUGH MONDAY MORNING. IN ADDITION TO DANGEROUS
CONDITIONS AT SEA ASSOCIATED WITH THE LARGE...LONG PERIOD NW
SWELL...LARGE BREAKING WAVES WILL BE LIKELY AT SOME HARBORS THIS
WEEKEND. PLEASE SEE THE MARINE WEATHER STATEMENT FOR MORE DETAILS.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
COASTAL FLOOD WARNING (SEE LAXCFWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
HIGH SURF ADVISORY (SEE LAXCFWLOX).
MARINE WEATHER STATEMENT (SEE LAXMWSLOX).

&&

$$

PUBLIC...RAT
AVIATION/MARINE...SUKUP
SYNOPSIS...RAT

WWW.WEATHER.GOV/LOSANGELES





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