Wind Advisory 135, NWS Los Angeles, CA

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1040 AM PST FRI NOV 23 2007

...STRONG SANTA ANA WIND EVENT EXPECTED FOR MUCH OF LOS ANGELES AND
VENTURA COUNTIES THIS AFTERNOON THROUGH SATURDAY...

...CRITICAL FIRE WEATHER CONDITIONS FOR MOST OF VENTURA AND
LOS ANGELES COUNTIES THIS AFTERNOON THROUGH SUNDAY AFTERNOON...

.SHORT TERM...
SATELLITE IMAGERY INDICATING QUICK BURNOFF OF LOW CLOUDS ACROSS THE
COASTAL AND VALLEY AREAS THIS MORNING AS INVERSION WAS QUITE WEAK.
LATEST OBS BEGINNING TO SHOW WEAK TO MODERATE OFFSHORE WINDS
BEGINNING TO DEVELOP ACROSS THE LA/VTU COUNTY MOUNTAINS AND A FEW
VTU COUNTY VALLEY SITES.  STRONG OFFSHORE WINDS STILL LOOK ON TRACK
FOR THIS AFTERNOON FOR THE MOUNTAINS OF LA/VTU COUNTIES. WATER VAPOR
IMAGERY ALSO SHOWS GOOD SUBSIDENCE BEGINNING TO MOVE ACROSS THE
REGION THIS MORNING. WINDS WILL QUICKLY STRENGTHEN THIS AFTERNOON.
AS STRONG UPPER LEVEL SUPPORT DEVELOPS OVER THE REGION. WENT AHEAD
AND TURNED HIGH WIND WATCHES INTO HIGH WIND WARNINGS FOR LA/VTU
COUNTY VALLEYS AS WELL AS THE COASTAL AREAS FROM THE HOLLYWOOD HILLS
TO MALIBU BEGINNING THIS EVENING AND CONTINUING THROUGH SATURDAY
AFTERNOON BEFORE WINDS BEGIN TO DIMINISH SOME SATURDAY NIGHT. LATEST
12Z WRF MODEL RUN INDICATED STRONG DOWNWARD MOTION FROM 700 MB TO
THE SURFACE ACROSS THE LA/VTU COUNTY MOUNTAINS AND VALLEYS THROUGH
TOMORROW AFTERNOON. WITH GOOD COLD AIR ADVECTION...FEEL CONFIDENT
THAT WRF MODEL IS REASONABLE. THEREFORE THE UPGRADE TO HIGH WIND
WARNINGS IN AREAS MENTIONED. A WIND ADVISORY WILL BE ISSUED FOR THE
VENTURA COASTAL PLAIN...BUT WILL HAVE TO BE MONITORED IN CASE WINDS
INCREASE TO WARNING CRITERIA OVERNIGHT.

...FROM PREVIOUS DISCUSSION...

THE MAIN STORY WILL BE THE WIND EVENT UNFOLDING TODAY...ESPECIALLY
ACROSS LOS ANGELES AND VENTURA COUNTIES...WITH INCREASINGLY CRITICAL
FIRE WEATHER CONDITIONS. A VIGOROUS VORT WAS CURRENTLY DROPPING SWD
ACROSS NRN CA. THIS WILL CONT TO DROP SWD TODAY...AND WINDS THRU
THE ATMOSPHERE WILL STRENGTHEN SHARPLY ACROSS THE REGION LATER THIS
MORNING AND THIS AFTERNOON. A 115 KNOT JET WILL NOSE INTO NERN
L.A. COUNTY THIS AFTERNOON...AND AS WIDESPREAD AND POWERFUL
SUBSIDENCE SPREADS ACROSS THE AREA...STRONG WINDS WILL SPREAD
INTO LOWER LEVELS OF THE ATMOSPHERE LATER TODAY AND TONIGHT.
THE WRF SHOWS 850 MB WINDS INCREASING TO 45 TO 50 KT ACROSS THE
MTNS OF L.A. AND ERN VTU COUNTIES THIS AFTERNOON...AND TO 55 TO 60
KT TONIGHT AND SAT MORNING. STRONG WINDS SHOULD BECOME WIDESPREAD IN
THE MTNS OF L.A. AND VTU COUNTIES THIS AFTERNOON. WINDS SHOULD
INCREASE RATHER QUICKLY...SO ALTHOUGH THERE MAY BE A PERIOD OF TIME
WITH JUST ADVISORY LEVEL WINDS...HAVE DECIDED TO JUST UPGRADE TO
HIGH WIND WARNINGS ACROSS THE MTNS STARTING THIS AFTERNOON.
IT SHOULD TAKE A BIT LONGER FOR THE WINDS TO SURFACE IN THE SANTA
MONICA MOUNTAINS...BUT WITH 950 MB WINDS FCST TO REACH 50 KNOTS
ACROSS L.A. COUNTY BY MIDNIGHT...BLV WARNING LEVELS WINDS ARE LIKELY
THERE...SO JUST STARTED THE WARNING THIS EVENING RATHER THAN
THIS AFTERNOON. WIND GUSTS COULD REACH 70 TO 75 MPH IN THE MOUNTAINS
OF VENTURA AND LOS ANGELES COUNTIES DURING THE PEAK OF THE
EVENT TONIGHT/SAT MORNING.

WITH THE WRF SHOWING 55 TO 60 KT WINDS AT 950 MB...HIGH WIND WARNING
LEVEL WINDS WILL PROBABLY BE REACHED IN MOST VALLEY LOCATIONS.
HOWEVER...DUE TO A BIT OF UNCERTAINTY AS TO HOW WIDESPREAD THEY WILL
BE IN THE VLYS...HAVE DECIDED TO LEAVE THE HIGH WIND WATCHES IN
PLACE...ALLOWING THE DAY SHIFT A CHANCE TO SEE ONE MORE MODEL
RUN...SATELLITE IMAGERY OF THE SUBSIDENCE...AND DEVELOPING WINDS IN
THE MTNS.

BASED ON VERY IMPRESSIVE ISENTROPIC CROSS SECTIONS...WAS CONSIDERING
ISSUING HIGH WIND WATCHES FOR CSTL SXNS OF VTU COUNTY AND CSTL SXNS
OF L.A. COUNTY BELOW PASSES AND CANYONS FROM MALIBU TO HOLLYWOOD...
BUT WINDS WILL PROBABLY REMAIN JUST UNDER THE CRITERIA FOR
WARNING...(SUSTAINED 40 MPH WINDS OR FREQUENT GUSTS TO 60 MPH.)
HOWEVER...IT IS A NEAR CERTAINTY THAT WIND ADVISORIES WILL
BE NEEDED IN THOSE AREAS.

FREEZING TEMPS IN THE ANTELOPE VALLEY AND AREAS OF FROST IN THE
INTERIOR VLYS OF SLO COUNTY AND THE CUYAMA VLY WILL END BY MID
MORNING SUNSHINE WARMS THE LAND. HOWEVER...WITH SO MUCH COLD AIR
ADVECTION ACROSS THE REGION...TEMPS WILL BE ON  THE COOL SIDE
ACROSS THE FCST AREA TODAY...DESPITE THE DEVELOPING OFFSHORE
FLOW.

ALTHOUGH THE NELY DIRECTION OF THE WINDS WILL BE LESS FAVORABLE FOR
WDSPRD STRONG WINDS IN THE MTNS OF SBA COUNTY...WINDS COULD STILL
REACH ADVISORY LEVELS IN THAT AREA FOR A WHILE TONIGHT INTO
EARLY SAT. FIRE WEATHER CONDITIONS COULD APCH CRITICAL LEVELS IN THE
SBA COUNTY MTNS AS WELL...AND IT IS POSSIBLE THAT RED FLAG WARNINGS
MAY HAVE TO BE EXPANDED INTO THAT AREA AS WELL.

WINDS SHOULD BEGIN TO DIMINISH BY LATE SAT AFTERNOON. HOWEVER...FLOW
REMAINS OFFSHORE SAT NIGHT INTO SUN MORNING...AND ADVISORY LEVEL
WINDS ARE POSSIBLE AGAIN...AT LEAST IN THE MTNS. LOW LEVEL GRADS MAY
ACTUALLY FLIP ONSHORE SUN AFTERNOON AS A FAST MOVING UPPER TROUGH
APCHS THE CST. HOWEVER...IT SHOULD REMAIN VERY DRY ACROSS THE AREA
INTO SUNDAY AFTERNOON...MAINTAINING CRITICAL FIRE WEATHER CONCERNS
ACROSS L.A. AND VTU COUNTIES.

MODELS SHOW AN UPPER TROUGH DIGGING SWD ACROSS THE ERN PAC SUN NIGHT
AND MONDAY. AT THIS TIME...IT APPEARS THIS SYSTEM WILL REMAIN TOO
FAR TO THE SW OF THE AREA TO PRODUCE MORE THAN A RETURN TO ONSHORE
FLOW...SOME COOLING...AND POSSIBLY SOME INCREASE IN CLOUDINESS
ACROSS THE REGION.

.LONG TERM...ANOTHER UPPER TROUGH IS FCST TO DROP FROM THE PAC NWS
INTO THE GREAT BASIN TUE INTO WED...BUT MODELS HAVE TRENDED A BIT
FLATTER WITH THIS SYSTEM. ANOTHER SYSTEM MOVING INTO THE W CST MAY
DIG A BIT FARTHER W THU...POSSIBLY BRINGING ANOTHER ROUND OF GUSTY
WINDS LATE IN THE WEEK...BUT MODELS ARE IN POOR AGREEMENT WITH THAT
SYSTEM...SO CONFIDENCE IS LOW. OVERALL...LOOKS LIKE GENERALLY COOL
WEATHER ACROSS THE AREA TUE THRU THU...WITH COLD OVERNIGHT POSSIBLE
ACROSS INTERIOR SECTIONS AND EVEN CSTL SXNS OF SLO AND SBA COUNTIES
MUCH OF THE WEEK.

&&

.FIRE WEATHER...23/1200Z
RED FLAG WARNINGS HAVE ALREADY BEEN POSTED FOR THE MOUNTAINS AND
VALLEYS OF LOS ANGELES COUNTIES...VALID FROM THIS AFTERNOON
THROUGH SUNDAY AFTERNOON. AS OFFSHORE WINDS BEGIN TO INCREASE
SHARPLY THIS AFTERNOON...LOOK FOR HUMIDITY VALUES TO LOWER
QUICKLY IN THE MOUNTAINS AND VALLEYS...WITH MANY AREAS FALLING TO
BETWEEN 10 AND 15 PERCENT. DURING THE PEAK OF THIS STRONG SANTA ANA
WIND EVENT TONIGHT INTO SATURDAY MORNING...WIDESPREAD HUMIDITY
VALUES BETWEEN 5 AND 15 PERCENT CAN BE EXPECTED ACROSS THE WARNING
AREA. WHILE THE WINDS ARE EXPECTED TO DIMINISH CONSIDERABLY BY LATE
SATURDAY AFTERNOON...THERE WILL LIKELY BE LINGERING LOW HUMIDITIES
IN THE MOUNTAINS AND VALLEYS THROUGH SUNDAY AFTERNOON. HUMIDITY
RECOVERIES TONIGHT AND SATURDAY NIGHT ARE EXPECTED TO BE VERY POOR.
THE COMBINATION OF STRONG WINDS...VERY LOW HUMIDITIES...AND VERY DRY
FUELS WILL CAUSE CRITICAL RED FLAG CONDITIONS IN THE MOUNTAINS AND
VALLEYS.

IT APPEARS INCREASINGLY LIKELY THAT CRITICAL FIRE WEATHER
CONDITIONS WILL AFFECT CSTL SXNS OF VTU COUNTY AND L.A. COUNTIES
(FROM MALIBU TO THE HOLLYWOOD HILLS)...AND RED FLAG WARNING WILL
LIKELY BE ISSUED FOR THOSE AREAS AS WELL. GUSTS TO 50 MPH
ARE POSSIBLE IN WIND FAVORED LOCATIONS ALONG WITH SINGLE DIGIT
HUMIDITIES TONIGHT INTO SUNDAY MORNING. HUMIDITIES ARE EXPECTED TO
RISE MORE QUICKLY ALONG THE COAST ON SUNDAY AFTERNOON AS ONSHORE
TRENDS BEGIN.

PLEASE REFER TO THE LATEST RED FLAG WARNING PRODUCT (LAXRFWLOX) FOR
MORE DETAILS.

.AVIATION...23/1800Z
SOME LINGERING STRATUS AND HAZE ACROSS THE COASTAL AND VALLEY TAFS
LATE THIS MORNING. WITH INCREASING OFFSHORE WINDS EXPECTD THIS
AFTERNOON...EXPECT ANY VSBYS RESTRICTIONS TO CLEAR OUT BY EARLY THIS
AFTERNOON. FOR THIS AFTERNOON THROUGH SATURDAY MORNING...RATHER
SIGNIFICANT OFFSHORE WINDS ARE EXPECTED. WILL BE SOME GUSTY NORTH
TO NORTHEAST WINDS AT THE USUAL LOCATIONS SUCH AS KVNY AND KBUR. ALSO
WITH STRONG WINDS ABOVE THE SURFACE...WIND SHEAR AND TURBULENCE WILL
BE AN ISSUE THROUGH THE TAF PERIOD.

KLAX...HIGH CONFIDENCE IN VFR CONDS THROUGH THE TAF PERIOD. AS THE
NORTH TO NORTHEAST WINDS DEVELOP ACROSS THE AREA...WILL EXPECT SOME
NORTHERLY WINDS THIS EVENING AND OVERNIGHT WITH SIGNIFICANT WIND
SHEAR AND TURBULENCE ABOVE THE SURFACE.

KBUR...HIGH CONFIDENCE IN VFR CONDS THROUGH THE TAF PERIOD. THE NORTH
WINDS ARE EXPECTED TO DEVELOP THIS AFTERNOON AND WILL INCREASE
THROUGH THE OVERNIGHT HOURS. SIGNIFICANT WIND SHEAR AND TURBULENCE
WILL BE LIKELY AT THE AIR FIELD STARTING THIS AFTERNOON.

.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING (SEE LAXNPWLOX).
RED FLAG WARNING (SEE LAXRFWLOX).
HIGH WIND WATCH (SEE LAXNPWLOX).
FIRE WEATHER WATCH (SEE LAXRFWLOX).
WIND ADVISORY (SEE LAXNPWLOX).
MARINE WEATHER STATEMENT (SEE LAXMWSLOX).

&&

PUBLIC...KAPLAN/BRUNO
AVIATION...THOMPSON

WWW.WEATHER.GOV/LOSANGELES

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
853 AM PST FRI NOV 23 2007

CAZ034>041-044>047-051>054-059-087-088-241400-
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-
LOS ANGELES COUNTY VALLEYS-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-
853 AM PST FRI NOV 23 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA.

.DAY ONE... TODAY

STRONG AND GUSTY OFFSHORE FLOW WILL FORM THIS AFTERNOON AND
OVERNIGHT TONIGHT OVER MUCH OF LOS ANGELES AND VENTURA COUNTIES.
THESE WINDS ARE CAPABLE OF PRODUCING DAMAGING WIND GUSTS TO 70 MPH
THROUGH FAVORED MOUNTAIN PASSES AND CANYONS...AND GUSTS UP TO 60 MPH
IN FAVORED VALLEY AREAS. THIS OFFSHORE FLOW WILL ALSO CAUSE THE
AIRMASS TO DRY OUT EXCESSIVELY...WHICH WHEN COUPLED WITH THE STRONG
WINDS HAS THE POTENTIAL TO PRODUCE AN ENVIRONMENT FAVORABLE FOR
RAPID FIRE GROWTH. AREAS OF THE COASTAL WATERS FROM VENTURA THROUGH
ORANGE COUNTY WILL ALSO BE IMPACTED BY THIS OFFSHORE FLOW...MAKING
FOR LOCALLY GUSTY WINDS AND CHOPPY SEAS LATE TONIGHT.

* HIGH WIND WARNING..........SEE WWUS76 KLOX - NPWLOX FOR DETAILS *

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

* HIGH WIND WATCH............SEE WWUS76 KLOX - NPWLOX FOR DETAILS *

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

* MARINE WEATHER STATEMENT...SEE FZUS76 KLOX - MWSLOX FOR DETAILS *

.DAYS TWO THROUGH SEVEN... SATURDAY THROUGH THURSDAY

STRONG AND GUSTY OFFSHORE FLOW WILL CONTINUE THROUGH SATURDAY
AFTERNOON OVER MUCH OF LOS ANGELES AND VENTURA COUNTIES. THESE WINDS
ARE CAPABLE OF PRODUCING DAMAGING WIND GUSTS TO 70 MPH THROUGH
FAVORED MOUNTAIN PASSES AND CANYONS...AND GUSTS UP TO 60 MPH IN
FAVORED VALLEY AREAS. THIS OFFSHORE FLOW WILL ALSO CAUSE THE AIRMASS
TO DRY OUT EXCESSIVELY...WHICH WHEN COUPLED WITH THE STRONG WINDS
HAS THE POTENTIAL TO PRODUCE AN ENVIRONMENT FAVORABLE FOR RAPID FIRE
GROWTH THROUGH SUNDAY MORNING. AREAS OF THE COASTAL WATERS FROM
VENTURA THROUGH ORANGE COUNTY WILL ALSO BE IMPACTED BY THIS OFFSHORE
FLOW...MAKING FOR LOCALLY GUSTY WINDS AND CHOPPY SEAS THROUGH EARLY
SATURDAY AFTERNOON.THERE WILL BE A CONTINUED THREAT OF SUB-FREEZING
NIGHT THROUGH EARLY MORNING TEMPERATURES IN THE ANTELOPE
VALLEY...INTERIOR VALLEYS OF SLO COUNTY...AND THE CUYAMA VALLEY
THROUGH AT LEAST SATURDAY.

* HIGH WIND WARNING..........SEE WWUS76 KLOX - NPWLOX FOR DETAILS *

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

* HIGH WIND WATCH............SEE WWUS76 KLOX - NPWLOX FOR DETAILS *

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

* MARINE WEATHER STATEMENT...SEE FZUS76 KLOX - MWSLOX FOR DETAILS *

.SPOTTER INFORMATION STATEMENT...

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

KAPLAN