Flash Flood Warning 14, NWS Los Angeles, CA

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
935 AM PDT TUE OCT 26 2004

.SHORT TERM...
THE LEADING EDGE OF THE FRONTAL BAND HEAVY RAIN HAS CONTAINED A
RATHER POTENT LINE OF CONVECTION PRODUCING WIND GUSTS NEAR SEVERE
CRITERIA (GUST TO 56 MPH AT HEARST CASTLE) AS IT MOVED THROUGH
NORTHWESTERN SAN LUIS OBISPO COUNTY. THE LINE OF CONVECTION HAS
DIMINISHED IN INTENSITY AS IT APPROACHES SAN LUIS OBISPO. LOW-LEVEL
850 MB JET NOT AS STRONG AS MODELS WERE FORECASTING LAST NIGHT...BUT
STILL ON THE ORDER OF 35 TO 45 MPH. SHOWERS ARE ALREADY DEVELOPING
AHEAD OF THE MAIN BAND ACROSS SANTA BARBARA COUNTY. LOOKS LIKE THE
THE TIMING OF THE STEADY HEAVIER RAIN IS NOW AHEAD OF THE SCHEDULE
DEPICTED BY THE 12Z ETA RUN...AT LEAST UP NORTH. THE ETA DOES SLOW
THE EASTWARD PROGRESSION DOWN SOUTH OF POINT CONCEPTION AND THIS
MAKES SENSE AS THE VERY STRONG UPPER LEVEL JET DIGS DOWN THE
BACKSIDE OF THE UPPER LEVEL TROUGH. ONLY CHANGES TO ZONES THIS
MORNING WERE TO ADJUST POP/WX PHRASING FOR CENTRAL COAST CHANGE HIGH
WIND WATCH TO HIGH WIND WARNING FOR SBA COUNTY MOUNTAINS. ALL OTHER
PARAMETERS OF THE FORECAST ARE ON TRACK AND STILL LOOKING AT THE
POTENTIAL FOR A VERY ACTIVE EARLY MORNING PERIOD WEDNESDAY FOR
VENTURA AND LOS ANGELES COUNTIES.

...FROM PREVIOUS DISCUSSION...

VERY IMPRESSIVE GULF OF ALASKA STORM HAS BEEN CHARGING SOUTHWARD
ALONG THE CALIFORNIA COAST OVERNIGHT. AS NOTED IN LATEST SPENES
MESSAGE...EXTREMELY STRONG JET IS DIGGING DOWN THE BACK SIDE OF THE
UPPER TROF...WHICH SHOULD MAINTAIN THIS ENERGETIC SYSTEM ALL THE WAY
THROUGH SO CAL. TIMING AND QPF AMOUNTS APPEAR TO BE PRETTY MUCH ON
TRACK...ALTHOUGH THE SYSTEM APPEARS TO BE MOVING ABOUT 3 HOURS
FASTER THAN THE ETA. RAINFALL AMOUNTS COULD RIVAL THOSE OBSERVED
DURING LAST WEEKS STORM...AS LOW LEVEL CONVERGENCE...UPPER DYNAMICS
AND OROGRAPHIC LIFT ARE ALL FAVORABLE. AM ALSO CONCERNED ABOUT THE
POSSIBILITY OF SEVERE WX TONIGHT...AS A NUMBER OF PARAMETERS APPEAR
TO COME TOGETHER IN THE 06-12Z PERIOD ALONG THE COAST FROM SBA-LAX.
STRONG LOW LEVEL WIND SHEAR...GOOD INSTABILITY AND VERY GOOD INFLOW
WINDS COULD CONTRIBUTE TO SOME SEVERE TSTMS AND POSSIBLE WATERSPOUTS
TONIGHT OR EARLY WED AM.

WINDS ARE FCST TO BE QUITE STRONG WITH THIS SYSTEM AS WELL...AND
WIND ADVISORIES ARE ALREADY IN EFFECT FOR MOST OF SLO/SBA COUNTIES.
HAVE POSTED HIGH WIND WATCHES FOR THE SBA AND SMO MTNS...AS
WORKSTATION ETA INDICATES PRE-FRONTAL WINDS OF 35-50 KT IN THESE
AREAS TONIGHT. WIND ADVISORIES MAY BE NEEDED FOR THE SBA SOUTH COAST
AND THE COASTS/VALLEYS OF VTU/LA COUNTIES AS WELL...BUT WILL LET THE
DAY SHIFT EVALUATE THIS FURTHER. WIND OBSERVATIONS FROM THE BAY AREA
AND ADJACENT COASTAL WATERS HAVE NOT BEEN TERRIBLY IMPRESSIVE THUS
FAR...BUT THIS MAY CHANGE AS THE DAY PROGRESSES.

WINTRY WX THREAT CONTINUES FOR THE LA/VTU MTNS TONIGHT AND WED...
AND HAVE OPTED TO CONTINUE THE WINTER STORM WATCHES FOR THESE AREAS.
WINTER STORM WARNINGS WILL LIKELY BE ISSUED LATER TODAY. WITH THE
STRONG SOUTHERLY FLOW AHEAD OF THE COLD FRONT...SNOW LEVELS WILL
REMAIN ABOVE 7K FEET THROUGH TONIGHT...BUT SHOULD DROP TO THE SKI
RESORT LEVELS WED. EXPECTING ACCUMULATIONS OF 2-3 FT ABOVE 7K...AND
4-12 INCHES FROM 5K-7K. STRONG WINDS...LOW VISIBILITIES AND POSSIBLE
MUD AND ROCKSLIDES WILL ADD TO THE TRAVEL HAZARDS.

MAIN BAROCLINIC ZONE SHOULD CLEAR LA COUNTY WED MORNING...WITH
SHOWERS CONTINUING ACROSS THE DISTRICT THROUGH THE DAY. COULD BE
SCATTERD TSTMS AS WELL WITH THE UPPER COLD POOL NEARBY CAUSING STEEP
LAPSE RATES. ACTIVITY SHOULD GRADUALLY DIMINISH WED NIGHT...AND
END OVER THE MTNS ON THU.

.LONG TERM...
LONG RANGE MODELS CONSISTENT WITH LAST NIGHTS RUNS...PROJECTING A
MUCH QUIETER WEATHER PATTERN ON TAP FOR THE EXTENDED PERIOD. AN
UPPER RIDGE BUILDS OVER THE EAST PAC AND NOSES INTO CALIFORNIA
FRI-SAT. A WEAK SYSTEM MOVES THROUGH ON SUN...BUT STILL LOOKS LIKE
AN INSIDE SLIDER WITH THE LIMITED MOISTURE REMAINING TO THE NORTH OF
OUR DISTRICT. DRY NW FLOW FLOW ALOFT WILL PREVAIL THROUGH EARLY NEXT
WEEK...WITH GENERALLY PARTLY CLOUDY SKIES...AND MAX TEMPS RUNNING
SLIGHTLY BELOW NORMAL. NEW GFS HAS THE EAST PAC RIDGE REMAINING IN
PLACE ALONG 140W FROM THE WEEKEND RIGHT THROUGH TEN DAYS...SO TODAYS
BIG STORM SHOULD BE THE LAST ONE FOR A WHILE.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH (SEE LAXFFALOX).
WINTER STORM WATCH (SEE LAXWSWLOX).
HIGH WIND WARNING/WATCH/WIND ADVISORY (SEE LAXNPWLOX).
GALE WARNING (SEE LAXCWFLOX).
SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).
MARINE WEATHER STATEMENT (SEE LAXMWSLOX).

&&

MOYER/JACOBSON

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
600 AM PDT TUE OCT 26 2004

CAZ034>041-044>047-051>054-059-087-088-271300-
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-
600 AM PDT TUE OCT 26 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA.

.DAY ONE... TODAY

A STRONG STORM SYSTEM WHICH ORIGINATED IN THE GULF OF ALASKA WILL
CONTINUE MOVING SOUTH ALONG THE CALIFORNIA COAST...AND AFFECT
CENTRAL AND SOUTHERN CALIFORNIA TODAY THROUGH WEDNESDAY. HEAVY
RAINFALL IS EXPECTED WITH THIS SYSTEM.

A FLASH FLOOD WATCH REMAINS IN EFFECT FOR THE MOUNTAINS AND ADJACENT
FOOTHILLS TODAY THROUGH WEDNESDAY. THE BURN AREAS WILL BE ESPECIALLY
VULNERABLE TO ADDITIONAL MUD SLIDES AND DEBRIS FLOWS. RAINFALL RATES
WITH THIS STORM ARE EXPECTED TO BE QUITE INTENSE...WITH RATES OF ONE
TO ONE AND ONE HALF INCHES PER HOUR POSSIBLE...ESPECIALLY ACROSS
SOUTH FACING MOUNTAIN AND FOOTHILL LOCATIONS. IN ADDITION...GENERAL
FLOOD ADVISORIES WILL LIKELY BE REQUIRED FOR MUCH OF THE FORECAST
REGION...DUE TO TYPICAL FLOODING OF ROADWAYS AND STREAMS.

A WINTER STORM WATCH ALSO REMAINS IN EFFECT FOR THE MOUNTAINS OF LOS
ANGELES AND VENTURA COUNTIES. THIS WILL LIKELY BE UPGRADED TO A
WINTER STORM WARNING LATER TODAY.

OTHER PORTIONS OF CENTRAL AND SOUTHERN CALIFORNIA WILL BE VULNERABLE
TO GUSTY WINDS WITH THIS SYSTEM. HIGH WIND WATCHES AND WIND
ADVISORIES HAVE BEEN POSTED FOR MUCH OF THE AREA.

THERE WILL BE A CHANCE OF THUNDERSTORMS AS THE COLD FRONT MOVES
THROUGH THE REGION TODAY AND TONIGHT. SEVERE WIND GUSTS...HAIL AND
WATERSPOUTS WILL BE POSSIBLE IN ASSOCIATION WITH A FEW OF THE
STRONGER THUNDERSTORMS.

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

* FLOOD WATCH................SEE WGUS66 KLOX - FFALOX FOR DETAILS *

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

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

* GALE WARNING...............SEE FZUS56 KLOX - CWFLOX FOR DETAILS *

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

* SPECIAL WEATHER STATEMENT..SEE WWUS86 KLOX - SPSLOX FOR DETAILS *

.DAYS TWO THROUGH SEVEN... WEDNESDAY THROUGH MONDAY

THE HEAVY RAIN IS EXPECTED TO EXIT LOS ANGELES COUNTY WEDNESDAY
MORNING. HOWEVER...WINTRY CONDITIONS WILL CONTINUE IN THE MOUNTAINS
THROUGH WEDNESDAY NIGHT. THERE WILL ALSO BE A THREAT OF
THUNDERSTORMS THROUGH WEDNESDAY EVENING...AS A COLD AND UNSTABLE
AIRMASS MOVES OVER THE REGION.

WEATHER CONDITIONS SHOULD IMPROVE ON THURSDAY AS THE STORM SYSTEM
MOVES FURTHER EAST. ONCE THE STORM EXITS THE REGION...QUIET WEATHER
IS EXPECTED FOR THE REMAINDER OF THE PERIOD THROUGH NEXT MONDAY.

* FLOOD WATCH................SEE WGUS66 KLOX - FFALOX FOR DETAILS *

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

.SPOTTER INFORMATION STATEMENT...

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

JACOBSON