Winter Storm Watch 3, NWS Los Angeles, CA

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
135 PM PDT FRI MAR 23 2012

.SYNOPSIS...

A STORM WILL MOVE SOUTH OVER THE REGION LATE SATURDAY AND SUNDAY
BRINGING PERIODS OF HEAVY RAIN AND MOUNTAIN SNOW. THE LOW WILL MOVE
EAST ON MONDAY FOR FAIR WEATHER. ANOTHER LOW WILL APPROACH BY
MIDWEEK FOR POSSIBLE LIGHT RAIN IN SAN LUIS OBISPO AND SANTA BARBARA
COUNTIES. THE TEMPERATURES WILL BE BACK TO SEASONAL NORMALS ON
THURSDAY.

&&

.SHORT TERM (TODAY-MON)...MARINE LYR STARTING TO CLEAR ACROSS THE
SOUTHERN AREAS BUT IT'S BEEN SLOW GOING AND STILL REALLY STRUGGLING
IN SRN SBA COUNTY. EXPECT THIS CLEARING TREND TO CONTINUE THROUGH
THE EVENING, BUT THEN SOME CLOUDS RETURNING TO LA COUNTY LATER
TONIGHT BEFORE CLEARING SATURDAY AFTERNOON. SHOULD ACTUALLY SEE SOME
WARMING SATURDAY WITH MORE SUNSHINE AND SOUTHERLY FLOW AHEAD OF THE
SAT NIGHT/SUNDAY STORM.

WE THEN TURN OUR ATTENTION TO THE STORM FOR THE LATTER HALF OF THE
WEEKEND. 12Z MODELS DID SLOW THE ARRIVAL SOMEWHAT AS THE FRONT
STALLS FOR A LITTLE WHILE OFF THE CENTRAL COAST THEN PIVOTS INTO PT
CONCEPTION LATE SATURDAY NIGHT. HOWEVER, THERE IS STILL ABOUT 6
HOURS OF DIFFERENCE BETWEEN THE FASTER GFS AND THE OTHER MODELS,
THOUGH I SEE NOW THE 18Z NAM HAS SLOWED FURTHER AND LINES UP VERY
WELL WITH THE 12Z GFS. PRECIP AMOUNTS STILL LOOK PRETTY GOOD AS
STRONG SOUTHERLY FLOW SHOULD DO A GOOD JOB ENHANCING PRECIP RATES AS
THE FRONT HITS THE TRANSVERSE RANGE. THE LOCAL WRF MODEL DOES SHOW A
VERY SHALLOW LAYER OF EASTERLY FLOW AT THE SURFACE BUT I DON'T THINK
THIS WILL HAVE A SIGNIFICANT IMPACT ON RAINFALL AMOUNTS UNLESS THE
EASTERLY FLOW RUNS DEEPER THROUGH THE LOW LVLS THAN EXPECTED.

SNOWFALL SHOULD BE SIGNIFICANT FOR HIGHER ELEVATIONS, ESPECIALLY
THOSE ABOVE 6000 FEET. WILL BE ISSUING A WINTER STORM WATCH FOR THE
VENTURA/LA MOUNTAINS, MAINLY FOR SUNDAY AND SUNDAY NIGHT. SNOW
LEVELS WILL BE A LITTLE TRICKY. MODELS INDICATE THEM RUNNING BETWEEN
5000-6000 FEET SUNDAY, BUT WITH THE STRONG SOUTHERLY FLOW AHEAD OF
AND WITH THE FRONT THEY MIGHT BE A TAD HIGHER THAN THAT, ESPECIALLY
ON SOUTH FACING SLOPES. FEEL CONFIDENT THAT RESORTS WILL DO WELL
WITH THIS EVENT, BUT NOT SO CONFIDENT BELOW 6000 FEET. AM HOLDING
OFF ISSUING A WATCH FOR SBA MOUNTAINS AT THIS TIME FOR THIS REASON
AS THE MTNS THERE PRETTY MUCH TOP OUT AROUND 6000 FEET. SNOW AMOUNTS
THERE MAY BE MORE IN THE ADVISORY RANGE.

PRECIP EXPECTED TO START TAPERING OFF LATE SUNDAY WITH JUST SOME
LINGERING SHOWERS MONDAY, MAINLY OVER THE MTNS AND ERN/SRN LA COUNTY.

.LONG TERM (TUE-FRI)...DRY AND A LITTLE WARMER MOST AREAS TUESDAY.
BY LATE TUESDAY INTO WEDNESDAY MOISTURE FROM THE TAIL END OF A
SYSTEM MOVING INTO NORTHERN CALIFORNIA WILL BRUSH THE CENTRAL COAST
AND LEFT IN THE SLIGHT CHANCE POPS WE HAD GOING FOR THOSE AREAS. THE
FRONT WASHES OUT AS IT MOVES SOUTH SO NO PRECIP EXPECTED SOUTH OF PT
CONCEPTION BUT POSSIBLY SOME INCREASE IN CLOUDS WED. THEN A LITTLE
RIDGE STARTS TO BUILD OVER THE AREA THU/FRI FOR DRY WEATHER AND A
WARMING TREND.

&&

.AVIATION...23/1800Z.

MID/UPPER LEVEL TROUGH OF LOW PRESSURE UPSTREAM WILL GRADUALLY
APPROACH. MID/UPPER LEVEL MODERATE/STRONG SOUTHWEST WINDS WILL
PREVAIL OVER THE AREA. LOW LEVEL CLOUD FIELD WITH TOPS AROUND 035
NEAR SHORE WILL GRADUALLY LESSEN AREALLY AND TOPS MAY DIFFER BY
MINUS 1KFT SAT MORNING. WEAK SOUTHERLY GRADIENT THROUGH 24/20Z THEN
MODERATE SOUTHERLY THEREAFTER.

KLAX...CHANCE CIGS 022-028 THROUGH 24/04Z THEN CHANCE CIGS 014
BETWEEN 24/04-24/17Z.

KBUR...CHANCE CIGS 015 THROUGH 23/22Z THEN CHANCE CIGS 027 BETWEEN
23/22-24/06Z AND CHANCE CIGS 016 24/06-24/16Z.

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

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH (SEE LAXWSWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).

&&

PUBLIC...WOFFORD
AVIATION...30
SYNOPSIS...SETO

WWW.WEATHER.GOV/LOSANGELES

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
212 PM PDT FRI MAR 23 2012

CAZ034>041-044>046-051>054-059-087-088-547-548-241300-
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-
212 PM PDT FRI MAR 23 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA.

.DAY ONE... TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED.

.DAYS TWO THROUGH SEVEN... SATURDAY THROUGH THURSDAY

A STORM SYSTEM WILL LIKELY BRING RAIN AND MOUNTAIN SNOW TO THE
REGION OVER THE WEEKEND. IT APPEARS THAT THE BULK OF THE STORM WILL
OCCUR LATE SATURDAY NIGHT INTO SUNDAY NIGHT. PRECIPITATION MAY BE
HEAVY AT TIMES. THERE WILL BE A CHANCE OF THUNDERSTORMS SUNDAY INTO
SUNDAY NIGHT. THERE WILL BE GUSTY SOUTH WINDS SATURDAY AFTERNOON
THROUGH SUNDAY MORNING ACROSS SAN LUIS OBISPO AND SANTA BARBARA
COUNTIES...AND IN THE MOUNTAINS. SIGNIFICANT SNOW COULD FALL AT
LEVELS LOW ENOUGH TO AFFECT TRAVEL ON INTERSTATE 5 OVER THE
GRAPEVINE LATE SUNDAY AND SUNDAY NIGHT.

* WINTER STORM WATCH.........SEE WWUS46 KLOX - WSWLOX 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.

WOFFORD