Gale Warning 7, NWS Los Angeles, CA

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
230 AM PST SAT FEB 23 2013

.SYNOPSIS...

DRY AND MILD CONDITIONS ARE EXPECTED THROUGH NEXT WEEK. HIGH
PRESSURE BUILDING INTO THE GREAT BASIN WILL GENERATE A MODERATE TO
LOCALLY STRONG SANTA ANA WIND EVENT TONIGHT AND SUNDAY. THE OFFSHORE
FLOW WILL ABATE MONDAY THROUGH WEDNESDAY. HOWEVER BY NEXT THURSDAY
AND FRIDAY...THERE IS THE POTENTIAL FOR ANOTHER ROUND OF MODERATE TO
STRONG NORTHEASTERLY WINDS.

&&

.SHORT TERM (TODAY-MON)...OVERALL...00Z MODELS IN GOOD SYNOPTIC
AGREEMENT THROUGH THE SHORT TERM. AT UPPER LEVELS...TROUGH WILL DIVE
INTO THE GREAT BASIN TODAY...THEN RIDGE WILL BUILD IN FROM THE WEST
ON SUNDAY...ONLY TO BE FLATTENED A BIT ON MONDAY AS ANOTHER TROUGH
MOVES IN THE GREAT BASIN. NEAR THE SURFACE...GOOD NORTHWESTERLY FLOW
TODAY WILL SHIFT TO NORTHEASTERLY TONIGHT...AND REMAIN NORTHEASTERLY
THROUGH MONDAY.

FORECAST-WISE...PROBLEM OF THE DAY WILL CONTINUE TO BE THE WINDS.
WITH THE DEVELOPING WEST-NORTHWEST FLOW TODAY...GUSTY WINDS WILL
LIKELY DEVELOP ACROSS THE ANTELOPE VALLEY THIS AFTERNOON/EVENING.
IN FACT...BOTH THE GFS AND NAM MOS NUMBERS FOR LANCASTER HAVE 30
KNOT WINDS THIS AFTERNOON. SO...STRONG ADVISORY-LEVEL WEST TO
NORTHWEST WINDS ARE EXPECTED ACROSS THE ANTELOPE VALLEY. ALSO
WOULD NOT BE SURPRISED TO SEE THE WINDIER SPOTS IN THE FOOTHILLS
(LAKE PALMDALE, ETC.) ACTUALLY HAVE SOME LOCALIZED WIND GUSTS
EXCEEDING WARNING LEVELS. CURRENTLY...AN ADVISORY IS IN EFFECT FOR
THE ANTELOPE VALLEY THROUGH THIS EVENING AND WILL REMAIN IN PLACE
WITH THE MORNING FORECAST.

OVERNIGHT TONIGHT AND SUNDAY...THE FLOW WILL QUICKLY TURN
NORTHEASTERLY AS A 1032-1034 MB SURFACE HIGH BUILDS INTO THE GREAT
BASIN. AT THE SAME TIME...THERE LOOKS TO BE QUITE THE BIT OF UPPER
LEVEL WIND SUPPORT AND GOOD THERMAL ADVECTION. JUST AN EXAMPLE OF
THE POTENTIAL UPPER LEVEL WIND SUPPORT. THE NAM INDICATES 950 MB
WINDS 40-50 KT ACROSS THE AREA WHILE THE LOCAL HI-RES WRF HAS 950 MB
WINDS IN EXCESS OF 60 KT SUNDAY MORNING. ADDING IN THE GOOD COLD
ADVECTION...THIS SANTA ANA LOOKS TO BE A MODERATE-STRONG EVENT.
WITH THE MORNING FORECAST...WILL UPGRADE THE LAX/VENTURA MOUNTAINS
TO A HIGH WIND WARNING...WHILE KEEPING THE REST OF VENTURA COUNTY AS
WELL AS THE SANTA CLARITA VALLEY/SAN FERNANDO VALLEY/SANTA MONICAS
IN A STRONG ADVISORY. ALSO...IF THE 12Z MODELS CONTINUE TO TELL THE
SAME STORY...FUTURE SHIFTS MAY HAVE TO CONSIDER UPGRADING THE SANTA
CLARITA VALLEY AND SANTA MONICA MOUNTAINS TO A WARNING. HOWEVER
WILL LET THAT DECISION TO THE DAY SHIFT.

BY SUNDAY NIGHT/MONDAY...THE UPPER LEVEL WIND AND THERMAL SUPPORT
WANES DRAMATICALLY. SO...THE WINDS WILL BE MUCH LESS ACROSS VENTURA
AND LOS ANGELES COUNTIES ALTHOUGH SOME LOCALLY BREEZY CONDITIONS
WILL CONTINUE ACROSS THE MOUNTAINS.

GIVEN THIS WIND EVENT...PRIMARY FOCUS WILL BE ON VENTURA AND LOS
ANGELES COUNTIES. FOR SAN LUIS OBISPO AND SANTA BARBARA COUNTIES
THERE WILL SOME OFFSHORE WINDS THROUGH SUNDAY...BUT DO NOT
ANTICIPATE ANYTHING REACHING ADVISORY LEVELS. HOWEVER...IT IS NOT
OUT OF THE REALM OF POSSIBILITY TO HAVE A BRIEF PERIOD OF ADVISORY
LEVEL NORTHERLY WINDS ACROSS SOUTHERN SANTA BARBARA COUNTY THIS
EVENING. ONCE AGAIN...WILL LET THE DAY SHIFT LOOK CLOSER AT THAT
POSSIBILITY.

OTHER THAN THE WINDS...NO ISSUES ARE EXPECTED IN THE SHORT TERM.
SKIES WILL REMAIN MOSTLY CLEAR THROUGH MONDAY WITH JUST SOME
SCATTERED CIRRUS FLOATING OVER THE AREA. AS FOR TEMPS...TODAY SHOULD
BE VERY SIMILAR TO FRIDAY. ON SUNDAY...THE OFFSHORE FLOW WILL ALLOW
FOR SOME WARMING ACROSS THE COASTAL PLAIN DUE TO COMPRESSIONAL
WARMING...BUT THE COLD ADVECTION WILL BRING SOME COOLING TO THE
MOUNTAINS AND INTERIOR SECTIONS. ON MONDAY...AS THE WINDS ABATE BUT
OFFSHORE GRADIENTS CONTINUE...ALL AREAS SHOULD WARM A FEW DEGREES.

.LONG TERM (TUE-FRI)...OVERALL...00Z MODELS ARE IN DECENT SYNOPTIC
AGREEMENT THROUGH THE PERIOD...ALTHOUGH SOME DETAIL DIFFERENCES IN
THE MODELS LATE IN THE WEEK COULD IMPACT THE FORECAST NOTICEABLY. AT
UPPER LEVELS...RATHER FLAT RIDGE WILL REMAIN OVER THE EASTERN
PACIFIC TUESDAY/WEDNESDAY...THEN WILL AMPLIFY AND MOVE OVER THE AREA
THURSDAY/FRIDAY. NEAR THE SURFACE...A WEAK OFFSHORE PATTERN
WILL PREVAIL ACROSS THE AREA TUESDAY/WEDNESDAY (WITH THE POTENTIAL
FOR LOW GRADE ADVISORY-LEVEL WINDS TUESDAY MORNING)...BUT BY
THURSDAY AND FRIDAY...BOTH THE GFS AND ECMWF BUILD STRONG SURFACE
HIGH PRESSURE INTO THE GREAT BASIN (RESULTING IN ANOTHER POTENTIALLY
SIGNIFICANT OFFSHORE WIND EVENT).

FORECAST-WISE...THE ABOVE PATTERN WILL RESULT IN RATHER UNREMARKABLE
WEATHER...EXCEPT FOR THE WINDS. SKIES SHOULD REMAIN MOSTLY CLEAR
THROUGH THE WEEK...WITH NO HINT OF ANY MARINE LAYER STRATUS. AS FOR
TEMPS...THE COMBO OF THE GRADUALLY BUILDING UPPER RIDGE AND OFFSHORE
FLOW WILL ALLOW FOR A NICE WARMING TREND (WITH SOME 80+ READINGS
EXPECTED BY FRIDAY).

AS FOR THE WINDS...THE SITUATION WILL NEED TO BE MONITORED CLOSELY.
AS MENTIONED PREVIOUSLY...THERE IS SOME CHANCE OF ADVISORY-LEVEL
NORTHEASTERLY WINDS TUESDAY MORNING. HOWEVER...MAIN PERIOD OF
CONCERN IS THURSDAY/FRIDAY. ON THURSDAY MORNING...MODELS INDICATE
GREAT BASIN SURFACE HIGH BETWEEN 1034 AND 1037 MB...WITH THE SURFACE
HIGH STRENGTHENING TO BETWEEN 1041 AND 1047 MB FRIDAY MORNING. AT
UPPER LEVELS...THE ECMWF IS INDICATING TEXTBOOK NORTHERLY FLOW WHILE
THE GFS IS JUST A LITTLE BIT LESS IMPRESSIVE. SO...AT THIS TIME...IT
LOOKS LIKE NEXT THURSDAY/FRIDAY COULD POTENTIALLY BE A HUMDINGER OF
A SANTA ANA WIND EVENT. HOWEVER BETWEEN NOW AND THEN...THE MODELS
COULD CHANGE THEIR TUNE...SO THE SITUATION WILL HAVE TO BE MONITORED
CLOSELY.

AS A SIDE NOTE ON FIRE WEATHER...THE UPCOMING WEEK WILL LIKELY BE AN
EXTENDED PERIOD OF WARM AND DRY CONDITIONS. SO...BY NEXT THURSDAY
AND FRIDAY (IF THE POTENTIAL WIND EVENT REMAINS STRONG)...THERE
COULD BE SOME VERY HEIGHTENED FIRE WEATHER CONCERNS.

&&

.AVIATION...23/1130Z...

WILL BE UPDATED WITH THE 12Z TAF PACKAGE.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING (SEE LAXNPWLOX).
WIND ADVISORY (SEE LAXNPWLOX).
GALE WARNING (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
HIGH SURF ADVISORY (SEE LAXCFWLOX).

&&

PUBLIC...RAT
AVIATION...BRUNO
SYNOPSIS...SUKUP

WWW.WEATHER.GOV/LOSANGELES

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
248 PM PST FRI FEB 22 2013

CAZ034>041-044>046-051>054-059-087-088-547-548-231400-
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-
248 PM PST FRI FEB 22 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA.

.DAY ONE... TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN... SATURDAY THROUGH THURSDAY

GUSTY WINDS WILL DEVELOP OVER THE AREA SATURDAY AND THEN PERSIST
THROUGH SUNDAY. WIND ADVISORIES ARE IN EFFECT FOR PORTIONS OF
VENTURA AND LOS ANGELES COUNTIES SATURDAY THROUGH SUNDAY. THE
COMBINATION OF A BUILDING NORTHWEST SWELL AND LOCALLY GENERATED
SWELLS WILL GENERATE HIGH SURF ALONG THE CENTRAL COAST SATURDAY
AFTERNOON. THE HAZARDOUS SURF WILL THEN PERSIST THROUGH SUNDAY
NIGHT.

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

* HIGH SURF ADVISORY.........SEE WHUS46 KLOX - CFWLOX FOR DETAILS *

.SPOTTER INFORMATION STATEMENT...

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