High Wind Watch 6, NWS Los Angeles, CA

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
200 PM PDT WED OCT 2 2013

.SYNOPSIS...
A WEAK ONSHORE FLOW PATTERN WILL KEEP CONDITIONS COOL ACROSS THE
AREA THROUGH THURSDAY WITH SOME NIGHT AND MORNING CLOUDS ACROSS THE
COASTAL PLAIN. FOR THURSDAY NIGHT THROUGH SUNDAY...AN EXTENDED SANTA
ANA WIND EVENT IS EXPECTED...WITH STRONG WINDS...WARM TEMPERATURES
AND CRITICAL FIRE WEATHER CONDITIONS. FOR EARLY NEXT WEEK...ONSHORE
FLOW WILL RETURN TO THE AREA...BRINGING COOLER CONDITIONS.

&&

...POTENTIAL MODERATE TO STRONG SANTA ANA WIND EVENT THURSDAY NIGHT
   THROUGH SATURDAY WITH EXTREME FIRE DANGER...

.SHORT TERM (TODAY-SAT)...OVERALL...12Z MODELS IN GOOD SYNOPTIC
AGREEMENT THROUGH THE PERIOD. AT UPPER LEVELS...LOW WILL DROP INTO
THE GREAT BASIN TONIGHT/THURSDAY (CENTERED OVER NORTHERN UTAH) THEN
WILL SHIFT EASTWARD FRIDAY/SATURDAY AS A RIDGE MOVES IN FROM THE
WEST. NEAR THE SURFACE...HIGH PRESSURE WILL BUILD INTO THE GREAT
BASIN THURDAY NIGHT/FRIDAY...AND WEAKEN SLIGHTLY FRIDAY NIGHT AND
SATURDAY.

FORECAST-WISE...MAIN ISSUE WILL BE POTENTIAL MODERATE TO STRONG
SANTA ANA WIND EVENT THURSDAY NIGHT THROUGH SATURDAY. VARIOUS HIGH
RES MODELS INDICATE A FINE STEW FOR A SIGNIFICANT OFFSHORE WIND
EVENT: STRONG OFFSHORE PRESSURE GRADIENTS FRIDAY MORNING/SATURDAY
MORNING (LAX-DAG FROM -6.0 MB TO -7.5 MB) AND IMPRESSIVE UPPER LEVEL
WIND SUPPORT (40-55 KNOTS BELOW 850 MB). EVEN THE GFS MODEL INDICATES
LAX-DAG GRADIENTS BETWEEN -2.5 AND -3.5 MB AND UPPER LEVEL WIND
SUPPORT BETWEEN 15 AND 25 KNOTS...WHICH ALTHOUGH WEAKER THAN THE
HIGH RES MODELS IS VERY IMPRESSIVE FOR A SPECTRAL MODEL.
SO...CONFIDENCE IS HIGH IN A MODERATE TO STRONG OFFSHORE WIND EVENT.
WITH THE AFTERNOON FORECAST PACKAGE...WILL ISSUE HIGH WIND WATCHES
FROM THURSDAY EVENING THROUGH SATURDAY AFTERNOON FOR ALL OF VENTURA
COUNTY AND LOS ANGELES COUNTY (EXCLUDING THE ANTELOPE VALLEY). THE
STRONGEST WINDS ARE EXPECTED IN THE MOUNTAINS (WIND GUSTS 60 TO 70
MPH) WITH SLIGHTLY WEAKER WINDS ACROSS THE COASTS AND VALLEYS (WIND
GUSTS 50 TO 60 MPH). THE STRONGEST WINDS WILL OCCUR FRIDAY
MORNING...WITH A LULL FRIDAY AFTERNOON/EVENING...THEN A SECONDARY
PEAK SATURDAY MORNING.

AS FOR CLOUDS...ONLY CLOUDS OF NOTE WILL BE MARINE LAYER STRATUS.
FOR TONIGHT/THURSDAY MORNING...STRATUS SHOULD BE LESS WIDESPREAD
WITH SOME PATCHY STUFF ACROSS THE CENTRAL COAST...AND AREAS OF
STRATUS ACROSS THE COASTAL PLAIN OF LOS ANGELES...AND
POSSIBLY...VENTURA COUNTIES. AS THE OFFSHORE DEVELOPS...THE STRATUS
COVERAGE SHOULD CONTINUE TO DIMINISH THURSDAY NIGHT AND FRIDAY
NIGHT.

AS FOR TEMPS...THURSDAY WILL BE ANOTHER COOL DAY. HOWEVER FOR FRIDAY
AND SATURDAY...NOTICEABLY WARMER TEMPS CAN BE EXPECTED WEST OF THE
MOUNTAINS DUE TO THE OFFSHORE FLOW AND BUILDING RIDGE OVERHEAD.
INLAND AREAS WILL REMAIN COOLER DUE TO THE COLD ADVECTION EFFECTS OF
THE NORTHEAST WINDS.

.LONG TERM (SUN-WED)...FOR THE EXTENDED...12Z MODELS START OFF IN
GOOD SYNOPTIC...GRADUALLY DIVERGE LATER IN THE PERIOD. AT UPPER
LEVELS...RIDGE WILL FLATTEN OUT ON SUNDAY...WITH THE AREA SANDWICHED
BETWEEN A RIDGE OVER THE EASTERN PACIFIC AND A LOW TO THE EAST. THE
ECMWF IS MORE PRONOUNCED AND FURTHER WEST WITH THE UPPER LOW
(DROPPING IT OVER THE UTAH/NEVADA) WHILE THE GFS KEEPS THE LOW
FURTHER TO THE EAST. NEAR THE SURFACE...OFFSHORE FLOW WILL BE
NOTICEABLY WEAKER SUNDAY MORNING...WITH WEAK DIURNAL FLOW MONDAY
THROUGH WEDNESDAY.

FORECAST-WISE...SUNDAY SHOULD SEE THE OFFSHORE WINDS DIMINISH
NOTICEABLY...WITH A WEAK ONSHORE BREEZE IN THE AFTERNOON WHICH WILL
HELP COOL TEMPS DOWN A BIT. FOR MONDAY THROUGH WEDNESDAY...EXPECT
THE COOLING TREND TO CONTINUE WITH THE ONSHORE FLOW GRADUALLY
STRENGTHENING EACH AFTERNOON. AS FOR CLOUDS...EXPECT CLEAR SKIES
THROUGH TUESDAY...WITH MAYBE SOME RETURN OF STRATUS TUESDAY
NIGHT/WEDNESDAY MORNING.

&&

.AVIATION...02/1800Z.
GOOD CONFIDENCE IN THE 18Z TAFS...EXCEPT ON THE CENTRAL COAST WHERE
MARINE CLOUD COVERAGE IS IN QUESTION. THE LOW CLOUDS WILL RETURN TO
THE COAST AND VALLEYS SOUTH OF POINT CONCEPTION.

KLAX AND KBUR...GOOD CONFIDENCE IN VFR CONDITIONS BECOMING MVFR
CONDITIONS THIS EVENING AND CONTINUING INTO THURSDAY MORNING.

&&

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

&&

PUBLIC...RAT
AVIATION...SWEET
SYNOPSIS...KJ

WWW.WEATHER.GOV/LOSANGELES

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
600 AM PDT WED OCT 2 2013

CAZ034>041-044>046-051>054-059-087-088-547-548-031300-
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-
600 AM PDT WED OCT 2 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA.

.DAY ONE... TODAY AND TONIGHT

HIGH SURF 10 TO 14 FEET WILL CONTINUE TO AFFECT THE WEST TO
NORTHWEST FACING BEACHES OF THE CENTRAL COAST. A HIGH RIP CURRENT
RISK WILL CONTINUE FROM SAN LUIS OBISPO TO LOS ANGELES COUNTY.

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

* HIGH RIP CURRENT RISK......SEE FZUS56 KLOX - SRFLOX FOR DETAILS *

.DAYS TWO THROUGH SEVEN... THURSDAY THROUGH TUESDAY

AN OFFSHORE WIND EVENT IS EXPECTED FRIDAY MORNING THROUGH
SATURDAY...WITH THE POTENTIAL FOR STRONGER WINDS AND LOWER
HUMIDITIES THAN LAST WEEK'S WIND EVENT. A SUNDOWNER WIND EVENT MAY
DEVELOP FOR THE SANTA YNEZ MOUNTAINS IN SANTA BARBARA COUNTY LATE
THURSDAY...THEN TRANSITION TO A SANTA ANA ACROSS VENTURA AND LOS
ANGELES COUNTIES BY EARLY FRIDAY MORNING. A PROLONGED PERIOD OF
SINGLE DIGIT HUMIDITIES AND VERY WARM TEMPERATURES WILL BE POSSIBLE
FRIDAY AND SATURDAY. CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED
AND A FIRE WEATHER WATCH IS IN EFFECT THURSDAY EVENING THROUGH
SATURDAY EVENING. A SPECIAL WEATHER STATEMENT HAS ALSO BEEN ISSUED
FOR THE WARM...DRY AND WINDY CONDITIONS.

* FIRE WEATHER WATCH.........SEE WWUS86 KLOX - RFWLOX 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.

ASR