High Wind Watch 12, NWS Los Angeles, CA

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
130 PM PST MON DEC 17 2012

.SYNOPSIS...

LINGERING SHOWERS WILL BECOME LESS WIDESPREAD THROUGH MONDAY
MORNING. AS A COLD FRONT MOVES THROUGH THE REGION...THE CHANCE OF
RAIN WILL THEN INCREASE MONDAY AFTERNOON FOR AREAS NORTH OF POINT
CONCEPTION AND MONDAY NIGHT INTO TUESDAY MORNING FOR AREAS SOUTH OF
POINT CONCEPTION. GUSTY NORTH WINDS WILL BE POSSIBLE FOR SOME AREAS
TUESDAY AFTERNOON INTO WEDNESDAY MORNING BEHIND THE FRONT. THE NEXT
WEATHER SYSTEM MAY APPROACH THE CENTRAL COAST LATE NEXT WEEK.

&&

.SHORT TERM (TODAY-THU)...WEAK COLD FRONT SLOWLY MAKING ITS WAY
SOUTH THROUGH CENTRAL CALIFORNIA TODAY. DOESN'T LOOK LIKE MUCH ON
SATELLITE AND RADAR AND IT WON'T BE MUCH FOR OUR AREA EITHER.
HOWEVER, MODELS DO SHOW A SLIGHT INTENSIFICATION AFTER IT ROUNDS PT
CONCEPTION TONIGHT AND AM BANKING ON THAT FOR VERIFYING MY HIGH POP
BUT LOW QPF FORECAST FOR TONIGHT AND EARLY TUESDAY. AMOUNTS EXPECTED
TO BE UNDER A QUARTER INCH, AND EVEN UNDER A TENTH FOR MANY AREAS.
ONCE AGAIN EASTERN LA COUNTY MAY BE THE GRAND PRIZE WINNER FOR OUR
CWA IN TERMS OF RAINFALL AMOUNTS.

THE MAIN IMPACT FROM THIS STORM WILL NOT BE THE PRECIPITATION WITH
THE FRONT BUT RATHER THE COLD AND GUSTY NORTHWEST WINDS BEHIND IT
TUESDAY AFTERNOON INTO EARLY WEDNESDAY. EXPECTING WINDS TO KICK UP
ACROSS ALL AREAS THROUGH THE DAY, POSSIBLY REACHING LOW END ADVISORY
LEVELS FOR THE COASTAL ZONES. BETTER CONFIDENCE IN ADVISORY AND EVEN
WARNING LEVEL WINDS FOR THE MOUNTAINS NEAR THE GRAPEVINE TUESDAY
EVENING INTO EARLY WEDNESDAY AS WELL AS THE ANTELOPE VALLEY, SANTA
CLARITA VALLEY, PORTIONS OF THE SAN FERNANDO AND VENTURA COUNTY
VALLEYS, AND SRN SBA COUNTY. NORTHERLY FLOW WILL PUSH MOISTURE AND
SCATTERED SHOWERS UP THE GRAPEVINE LATE TUESDAY INTO EARLY
WEDNESDAY, AND WITH SNOW LEVELS EXPECTED TO FALL TO AROUND 3000 FEET
THERE COULD BE SOME LIGHT ACCUMULATION OVER THE GRAPEVINE. 850 MB
TEMPERATURES FALL TO AROUND -6C SO TEMPS WILL BE EXTREMELY COLD WITH
SOME DANGEROUS WIND CHILLS IN THE MOUNTAINS.

OVERNIGHT LOWS WEDNESDAY AND THURSDAY MORNINGS WILL BE AMONG THE
COLDEST SO FAR THIS SEASON AND FROST ADVISORIES MAY BE NEEDED FOR
THE CENTRAL COAST AS WELL AS VENTURA AND LA VALLEYS. LOCATIONS THAT
ARE SUSCEPTIBLE TO NORTH AND NORTHWEST WINDS WILL SEE THEIR COLDEST
MORNING ON THURSDAY DUE TO THE WIND SHIFT TO THE NORTHEAST.

A COUPLE MORE COOL DAYS ON TAP TUE AND WED WITH LOWER ELEVATION
HIGHS MOSTLY IN THE 50S AND A FEW ISOLATED SPOTS IN THE LOW 60S. ON
THURSDAY A LITTLE INCREASE IN OFFSHORE FLOW AND BUILDING HEIGHTS
ALOFT WILL ALLOW TEMPERATURES TO WARM UP 3-6 DEGREES ON AVERAGE.

.LONG TERM (FRI-MON)...TIMING DIFFERENCES IN THE MODELS LEAD TO
LOWER THAN USUAL CONFIDENCE IN THE FORECAST FOR THE WEEKEND. THE GFS
HAS A FRONT COMING THROUGH FRIDAY AFTERNOON INTO EARLY SATURDAY
WHILE THE ECMWF IS A FULL 24 HOURS SLOWER THAN THAT AS IT PUMPS UP
THE RIDGE AHEAD OF IT AND STALLS THE FRONT OVER NRN CA. BOTH MODELS
SHOW IT BEING A PRETTY WEAK FRONT SO MINIMAL IMPACTS LOCALLY. THE
GFS HAS A SECOND SYSTEM ARRIVING LATER SUNDAY WHILE THE ECMWF IS
ABOUT 12 HOURS BEHIND AND WEAKER.

&&

.AVIATION...17/1800Z.

MID/UPPER LEVEL TROUGH OF LOW PRESSURE UPSTREAM WILL MOVE OVER THE
AREA. UPPER LEVEL STRONG WEST WINDS WILL BECOME STRONG SOUTHWEST
AFTER 18/00Z AND PERSIST WHILE MID LEVEL MODERATE WEST WINDS BECOME
MODERATE SOUTHWEST AFTER 18/09Z OVER THE AREA. RELATIVELY MOIST MID
LEVEL WINDS BETWEEN 17/21-18/18Z. A SURFACE FRONT IN THE VICINITY OF
KMRY WILL WEAKEN WHILE MOVING SOUTH AT APPROXIMATELY 23KT AND MOVE
OVER THE AREA. FREEZING LEVEL WAS AROUND 10KFT THIS MORNING AND WILL
DIFFER BY MINUS 3KFT AFTER 18/06Z AND CONTINUE TO DESCEND TO 4KFT BY
18/20Z.

KLAX...CHANCE CIGS 020-028 BETWEEN 18/06-18/13Z WITH CHANCE CIGS 009
AND -RA AT TIMES BETWEEN 18/09-18/13Z. CHANCE CIGS 010 AND CHANCE OF
-DZ AT TIMES BETWEEN 18/13-18/18Z.

KBUR...CHANCE CIGS 020-025 BETWEEN 18/06-13/13Z WITH A CHANCE OF
CIGS 009 AT TIMES 18/09-18/13Z THEN A CHANCE OF CIGS 010 AND -DZ AT
TIMES AFTER 18/13Z. CHANCE OF -RA BETWEEN 18/08-18/13Z.

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

&&

.MARINE...A RIDGE OF HIGH PRESSURE IS EXPECTED TO STRENGTHEN OVER
THE EASTERN PACIFIC TUESDAY MORNING AND BUILD INLAND FOLLOWING A
LANDFALLING LOW PRESSURE SYSTEM TUESDAY AFTERNOON. THE PRESSURE
GRADIENT IS EXPECTED TO STRENGTHEN NEAR SHORE TUESDAY MORNING
THROUGH TUESDAY EVENING. NORTHWEST WINDS WILL LIKELY STRENGTHEN TO
GALE FORCE OVER THE ENTIRE AREA TUESDAY AFTERNOON AND A WARNING WAS
ISSUED. THE GALES ARE EXPECTED TO DIMINISH WEDNESDAY MORNING. VERY
STEEP SEAS WILL EXIST TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING
BUILD TO 7 TO 10 FEET IN THE NEAR SHORE BASINS AND TO 12 TO 15 FEET
IN THE OUTER WATERS. OTHERWISE A LOW PRESSURE SYSTEM IS EXPECTED TO
DEVELOP IN THE CENTRAL GULF OF ALASKA WEDNESDAY AND STORM FORCE
WINDS WILL GENERATE SEAS AROUND 40 FEET. AND THE FETCH IS ORIENTED
300-310 DEGREES RELATIVE TO SOUTHWEST CALIFORNIA. GUIDANCE DIFFERED
SLIGHTLY ON THE SWELL SIZE AND ARRIVAL TIME. SWELLS ARE EXPECTED TO
BUILD FRIDAY MORNING THROUGH SATURDAY MORNING AND HIGH SURF IS
POSSIBLE ALONG ALL EXPOSED WEST AND NORTHWEST FACING SHORES FRIDAY
NIGHT THROUGH SATURDAY. THE TIDE WILL RANGE FROM AROUND 1 FOOT LATE
FRIDAY MORNING TO AROUND 3 FEET EARLY FRIDAY EVENING AND TO AROUND 5
FEET EARLY SATURDAY MORNING. STRONG RIP CURRENTS WILL LIKELY EXIST
IN THE VICINITY OF LARGE BREAKERS.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH (SEE LAXNPWLOX).
WIND ADVISORY (SEE LAXNPWLOX).
GALE WARNING (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).

&&

PUBLIC...MW
AVIATION...30
SYNOPSIS...SWEET

WWW.WEATHER.GOV/LOSANGELES

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
800 AM PST MON DEC 17 2012

CAZ034>041-044>046-051>054-059-087-088-547-548-181400-
SAN LUIS OBISPO COUNTY CENTRAL COAST-
SANTA BARBARA COUNTY CENTRAL COAST-SANTA YNEZ VALLEY-
SAN LUIS OBISPO COUNTY INTERIOR VALLEYS-CUYAMA VALLEY-
SANTA BARBARA COUNTY SOUTH COAST-VENTURA COUNTY COAST-
LOS ANGELES COUNTY COAST INCLUDING DOWNTOWN LOS ANGELES-
VENTURA COUNTY INTERIOR VALLEYS-VENTURA COUNTY COASTAL VALLEYS-
SANTA MONICA MOUNTAINS RECREATIONAL AREA-
SAN LUIS OBISPO COUNTY MOUNTAINS-
SANTA BARBARA COUNTY MOUNTAINS-VENTURA COUNTY MOUNTAINS-
LOS ANGELES COUNTY MOUNTAINS EXCLUDING THE SANTA MONICA RANGE-
ANTELOPE VALLEY-CATALINA ISLAND-SANTA CLARITA VALLEY-
LOS ANGELES COUNTY SAN FERNANDO VALLEY-
LOS ANGELES COUNTY SAN GABRIEL VALLEY-
800 AM PST MON DEC 17 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA.

.DAY ONE... TODAY AND TONIGHT

A WEAK COLD FRONT WILL BRING LIGHT RAIN TO THE CENTRAL COAST THIS
AFTERNOON AND THE REST OF THE AREA OVERNIGHT.

* SPECIAL WEATHER STATEMENT..SEE WWUS86 KLOX - SPSLOX FOR DETAILS *

.DAYS TWO THROUGH SEVEN... TUESDAY THROUGH SUNDAY

LOW SNOW LEVELS COULD BRING SNOW TO THE GRAPEVINE AREA ON TUESDAY.
STRONG NORTHWEST TO NORTH WINDS WILL DEVELOP TUESDAY AND LAST INTO
WEDNESDAY MORNING. THE WINDS WILL BE STRONGEST IN THE MOUNTAINS AND
THE ANTELOPE VALLEY. GALE FORCE WINDS WILL DEVELOP ACROSS ALL OF THE
COASTAL WATERS.

* GALE WARNING...............SEE WHUS76 KLOX - MWWLOX FOR DETAILS *

* SPECIAL WEATHER STATEMENT..SEE WWUS86 KLOX - SPSLOX FOR DETAILS *

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

BOLDT/RORKE