Red Flag Warning 34, NWS Los Angeles, CA

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
145 PM PST MON DEC 8 2008

.SHORT TERM (TODAY-THU)...WERE TRANSITIONING FROM A NORTHWEST TO A
NORTHEAST WIND PATTERN TONIGHT. IN THE INTERIM, GUSTY WINDS ARE
EXPECTED THROUGH THE I-5 CORRIDOR AND ANTELOPE VALLEY WHERE WIND
ADVIORIES ARE IN EFFECT. LATER TONIGHT AS THE SURFACE HIGH BUILDS
OVER NEVADA THE WINDS WILL SHIFT TO THE NORTHEAST AND OUR SANTA ANA
WIND EVENT WILL BEGIN. THE ONLY QUESTION AT THIS POINT IS TIMING AND
HOW FAR TO THE COAST ADVISORY LEVEL WINDS WILL GET. THERE IS A WEAK
LOW LVL INVERSION AND PLENTY OF MOISTURE TRAPPED BELOW IT. BUT THIS
TIME OF YEAR IT SHOULDNT TAKE TOO LONG FOR THE WINDS TO BLAST
THROUGH THE INVERSION AND BRING WINDS TO THE COASTAL AREAS. WILL LET
LATER SHIFTS ISSUE THE ADVISORIES FOR THE VALLEYS AND VENTURA COUNTY
COAST AS ADVISORY LEVELS WINDS THERE SHOULD ARRIVE AT OR AFTER
SUNRISE.

WITH THE OFFSHORE FLOW TUESDAY WILL COME WARMER TEMPS AT LOWER
ELEVATIONS BUT COOLER TEMPS FOR THE MTNS/DESERTS. HAVE LEFT IN
PATCHY LOW CLOUDS NEAR THE COAST IN THE MORNING BUT THESE MAY BE
GONE BEFORE SUNRISE. COLD ADVECTION WILL LIMIT THE AMOUNT OF WARMING
WE SEE BUT LOWER VALLEYS AND COASTS SHOULD GENERALLY BE IN THE 70S
TUE.

NOT A LOT OF CHANGE IN SURFACE GRADIENTS TUE NIGHT/WED MORNING, BUT
UPPER SUPPORT IS PRETTY MUCH GONE SO WINDS SHOULD DROP OFF QUITE A
BIT. WILL KEEP THE ADVISORY GOING IN THE MTNS THROUGH WED AS MODEL
CROSS SECTIONS SHOW ENOUGH WIND TO SUPPORT A LOW LVL WIND ADVISORY.
IN THE VALLEYS AND COAST WINDS MAY ONLY REACH ADVISORY LEVELS ON
TUE. WARMING EXPECTED IN ALL AREAS WED, THOUGH MODELS STILL SHOWING
A VERY MINIMAL AMOUNT OF WARMING BELOW 850MB. THIS IS A LITTLE
SURPRISING GIVEN THE STRENGTH OF THE HIGH PRESSURE ALOFT AND
THICKNESSES IN THE MID 560S, BUT MODELS HAVE BEEN CONSISTENT WITH
THIS. IF THIS PANS OUT THEN HIGHS WED SHOULD TOP OUT IN THE LOWER
80S AT BEST, AND POSSIBLY ONLY UPPER 70S.

ANOTHER SIGNIFICANT IMPACT OF THIS OFFSHORE FLOW WILL BE VERY COLD
NIGHTS IN WIND PROTECTED LOCATIONS. WELL SEE TEMPERATURES DROPPING
TONIGHT INTO THE 30S AND 40S AT LOWER ELEVATIONS AND UPPER 20S IN
THE DESERTS. HOWEVER, TUE NIGHT SHOULD BE THE COLDEST NIGHT WITH
LOWS IN THE UPPER TEENS POSSIBLY IN THE AV AND LOWER 30S ALONG THE
CENTRAL COAST AND COLDER VALLEYS OF VTU/LA COUNTIES. A FREEZE WATCH
WILL ALMOST CERTAINLY BE NEEDED IN THE AV AND FROST ADVISORIES
POSSIBLE FOR THE CENTRAL COAST.

OFFSHORE FLOW WEAKENS FURTHER THU, HOWEVER AIRMASS CONTINUES TO WARM
UP AND THU SHOULD BE THE WARMEST DAY ACROSS OUR AREA WITH HIGHS
POSSIBLY IN THE MID 80S IN THE WARMER VALLEYS.

.LONG TERM (FRI-MON)...MAJOR PATTERN CHANGE STARTING THIS COMING
WEEKEND. THIS HAS BEEN CONSISTENTLY ADVERTISED BY THE MODELS NOW
SINCE LAST WEEK AND THEY ARE IN SURPRISINGLY GOOD AGREEMENT TODAY AS
WELL. AS A  RESULT, CONFIDENCE IN THE OVERALL PATTERN IS VERY HIGH.
FRIDAY WELL BE TRENDING STRONGLY ONSHORE AND LOOK FOR HIGHS TO DROP
10-15 DEGREES ACROSS THE AREA, ESPECIALLY COAST AND VALLEYS. MAY
ALSO HAVE A LITTLE MARINE LYR ALONG THE COAST. ON SAT A COLD UPPER
UPPER LOW WILL DROP INTO THE PAC NW WITH A COUPLE OF LITTLE IMPULSES
MOVING INTO CA. MODELS INDICATE A FAIR AMOUNT OF MOISTURE BELOW 700
MB, WHICH IS LIKELY PARTIALLY A RESPONSE TO THE COOLER AIRMASS.
HOWEVER, WITH RAPDILY FALLING HEIGHTS AND STRONG COLD ADVECTION,
EVEN A SHALLOW MOIST LAYER COULD SUPPORT A FEW SHOWERS. SO IVE
ADDED 20 POPS TO ALL AREAS SAT. VERY LITTLE CHANGE SUNDAY AS THE
TROF CONTINUES TO DEEPEN ALONG THE WEST COAST. THE LOW WILL BE ABOUT
500 MILES WEST OF SFO MONDAY AFTERNOON. DONT REALLY SEE ANYTHING
ORGANIZED COMING THROUGH THE AREA, BUT THERE CONTINUES TO BE ENOUGH
MOISTURE AND COLD AIR AROUND TO JUSTIFY LOW POPS THROUGH MONDAY.
SNOW LEVELS THROUGH THE WEEKEND, PARTICULARLY SUNDAY AND MONDAY,
WILL BE AROUND 4000 OR POSSIBLY LOWER.

GOING FURTHER INTO TIME THE GFS AND ECMWF REALLY KICK INTO GEAR LATE
MONDAY INTO TUESDAY SHOWING A PRETTY SIGNIFICANT COLD FRONT MOVING
THROUGH THE AREA. THIS COULD BRING A DECENT AMOUNT OF RAIN WITH SNOW
DOWN TO VERY LOW ELEVATIONS. THE TROF IS VERY SLOW MOVING AND BOTH
MODELS KEEP US WET AND COLD THROUGH AT LEAST THURSDAY.

&&

.AVIATION...08/1830Z.
A RATHER LOW CONFIDENCE FORECAST DURING A PERIOD OF TRANSITION IN
THE WEATHER PATTERN. THE LOW LEVEL FLOW WILL SHIFT RAPIDLY FROM
ONSHORE FLOW WITH A DEEP LOW-LEVEL MOIST LAYER THIS AFTERNOON
THROUGH LATE TONIGHT TO OFFSHORE FLOW AND LOW LEVEL DRYING EARLY ON
TUESDAY. THE MOST LIKELY SCENARIO IS FOR THE LOW CLOUDS TO REFORM
THIS EVENING WITH MVFR CONDITIONS AND THE CLEARING IS EXPECTED TO
TAKE PLACE SHORTLY AFTER SUNRISE AS THE OFFSHORE FLOW AND DRYING
OVERCOMES THE LINGERING MOISTURE.

KLAX...LOW CONFIDENCE IN THE FORECAST. THE MOST LIKELY SCENARIO WITH
A 50 PERCENT CHANCE OF OCCURRENCE IS FOR THE LOW CLOUDS TO REFORM
EARLY THIS EVENING WITH MOSTLY CLOUDY SKIES OVERNIGHT FOLLOWED BY
FAIRLY RAPID CLEARING EARLY TUESDAY. THERE IS A 30 PERCENT CHANCE
THAT THE CLEARING WILL NOT OCCUR UNTIL 17-18Z. THERE IS A 20 PERCENT
CHANCE THAT THE CLEARING WILL OCCUR AROUND 08Z.

KBUR...LOW CONFIDENCE IN THE FORECAST. THE MOST LIKELY SCENARIO WITH
A 50 PERCENT CHANCE OF OCCURRENCE IS FOR THE LOW CLOUDS TO REFORM
THIS EVENING WITH MOSTLY CLOUDY SKIES OVERNIGHT FOLLOWED BY
FAIRLY RAPID CLEARING EARLY TUESDAY. THERE IS A 20 PERCENT CHANCE
THAT THE CLEARING WILL NOT OCCUR UNTIL 17-18Z. THERE IS A 30 PERCENT
CHANCE THAT THE CLEARING WILL OCCUR AROUND 08Z.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING (SEE LAXRFWLOX).
WIND ADVISORY (SEE LAXNPWLOX).
GALE WARNING (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).

&&

PUBLIC...WOFFORD
AVIATION...SWEET

WWW.WEATHER.GOV/LOSANGELES

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
229 PM PST MON DEC 8 2008

CAZ034>041-044>046-051>054-059-087-088-547-548-091400-
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-
229 PM PST MON DEC 8 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA.

.DAY ONE... TODAY

GUSTY WEST TO NORTHWEST WINDS WILL DEVELOP IN THE ANTELOPE VALLEY AS
WELL AS THE VENTURA AND LOS ANGELES COUNTY MOUNTAINS. WINDS WILL
SHIFT TO THE NORTHEAST AND BECOME MORE WIDESPREAD TONIGHT AS A SANTA
ANA WIND PATTERN DEVELOPS.

* WIND ADVISORY..............SEE WWUS76 KLOX - NPWLOX FOR DETAILS *

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

.DAYS TWO THROUGH SEVEN... TUESDAY THROUGH SUNDAY

GUSTY NORTHEAST WINDS WILL CONTINUE ACROSS PORTIONS OF VENTURA AND
LOS ANGELES COUNTIES THROUGH WEDNESDAY. THE COMBINATION OF GUSTY
WINDS...LOW HUMIDITIES...AND DRY FUELS WILL CREATE A HIGH FIRE RISK.
OVERNIGHT TEMPERATURES IN WIND PROTECTED LOCATIONS WILL DROP BELOW
FREEZING EARLY WEDNESDAY MORNING...ESPECIALLY THE ANTELOPE VALLEY
WHERE LOWS COULD DIP INTO THE HIGH TEENS. SUB-FREEZING TEMEPERATURES
ARE EXPECTED THURSDAY MORNING AS WELL. A MAJOR CHANGE IN THE WEATHER
PATTERN WILL BRING MUCH COOLER TEMPERATURES AND A SMALL CHANCE OF
RAIN OVER THE WEEKEND WITH LOW SNOW LEVELS.

* RED FLAG WARNING...........SEE WWUS86 KLOX - RFWLOX FOR DETAILS *

* WIND ADVISORY..............SEE WWUS76 KLOX - NPWLOX FOR DETAILS *

.SPOTTER INFORMATION STATEMENT...

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

WOFFORD