Flash Flood Warning 22, NWS Los Angeles, CA

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
230 PM PST MON JAN 10 2005

CORRECTED DAY OF WEEK AND DATE

SHORT TERM...A MAJOR...UPPER LEVEL TROUGH IS ORIENTED NORTH TO SOUTH
OFF THE COAST OF NORTHERN CALIFORNIA THIS AFTERNOON. THE UPPER LEVEL
LOW ASSOCIATED WITH THIS SYSTEM IS CENTERED ABOUT 300 NM NORTHWEST
OF SAN FRANCISCO. AHEAD OF THIS TROUGH...STRONG SOUTH TO SOUTHWEST
WINDS ALOFT COVER THE ENTIRE STATE OF CALIFORNIA...WITH EMBEDDED
SHORT WAVES CIRCULATING AROUND THE UPPER LOW. AT THIS TIME...THE
LATEST IN A SERIES OF SHORT WAVE TROUGHS IS JUST MOVING OUT OF
SOUTHERN CALIFORNIA WITH SHOWERS DIMINISHING FROM THE WEST OVER THE
SOUTH COAST. OVER THE CENTRAL COAST...LIGHT SHOWERS ARE ALREADY
BREAKING OUT AHEAD OF THE MAJOR TROUGH AS IT TAKES AIM ON CENTRAL
AND SOUTHERN CALIFORNIA.

THE MAJOR TROUGH ITSELF IS EXPECTED TO MOVE ONSHORE OVER CENTRAL
CALIFORNIA TONIGHT...AND THROUGH SOUTHERN CALIFORNIA ON TUESDAY.
THIS TROUGH IS EXPECTED TO PRODUCE RAINS OF SHORTER DURATION...BUT
HIGHER INTENSITY COMPARED TO TODAYS STORM SYSTEM. RAINFALL RATES IN
EXCESS OF AN INCH AN HOUR WILL BE POSSIBLE WITH THIS SYSTEM.
ADDITIONAL RAINFALL ACCUMULATIONS SHOULD RUN 1 TO 3 INCHES
COASTAL...WITH 3 TO 5 INCHES ALONG THE SOUTH FACING SLOPES. HIGHER
AMOUNTS...UP TO 8 INCHES...CAN BE EXPECTED TO OCCUR AT THE WETTER
LOCATIONS SUCH AS SAN MARCOS PASS...NORDHOFF RIDGE...OR OPIDS CAMP.
THUS...THERE IS A CONTINUING THREAT FOR MORE FLASH FLOODING AND
MUDSLIDES TONIGHT AND TUESDAY. FLOOD WATCHES REMAIN IN EFFECT FOR
SANTA BARBARA...VENTURA AND LOS ANGELES COUNTIES THROUGH TUESDAY
MORNING.

TUESDAY MORNING...THE MAJOR TROUGH PASSAGE WILL BE ACCOMPANIED BY A
COLDER AND MORE UNSTABLE AIR MASS WITH STRONGER DYNAMICS. AS A
RESULT...THERE WILL BE A GREATER POSSIBILITY FOR WATERSPOUTS...
SEVERE THUNDERSTORMS...AND EVEN SMALL TORNADOS. THE MAJOR THREAT
AREA FOR THIS ACTIVITY WILL BE COASTAL REGIONS SOUTH OF POINT
CONCEPTIONS...INCLUDING THE CHANNEL ISLANDS.

SNOW LEVELS ARE VERY HIGH TODAY...ABOVE 7000 FEET. THE PASSAGE OF
THE MAJOR TROUGH WILL DROP THE SNOW LEVELS TO 5000 FEET BY MID DAY
TUESDAY. TWO TO THREE FEET OF ADDITIONAL SNOW IS EXPECTED ABOVE 7000
FEET WITH UP TO A FOOT AT ELEVATIONS BETWEEN 5000 AND 7000 FEET.

SHOWERS SHOULD END FROM THE WEST LATE TUESDAY AS THE MAJOR TROUGH
RAPIDLY MOVES TO THE EAST AND OUT OF THE REGION. LOOK FOR DRY
WEATHER WEDNESDAY WITH WINDS TURNING OFFSHORE.

EXTENDED...MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT UNTIL SATURDAY
MORNING...THEN DIVERGE SIGNIFICANTLY. THE GFS MODEL IS ADVERTISING A
NEW PACIFIC STORM WHICH APPROACHES THE CENTRAL COAST OVER THE
WEEKEND. AT THE SAME TIME...THE ECMWF SHOWS A LESS INTENSE TROUGH
APPROACHING THE COAST. NOTABLY...THE GFS KEEPS THE CENTER OF THE
STORM OFF THE COAST. THROUGH EARLY NEXT WEEK. IN ANY CASE...WE CAN
EXPECT DRY...OFFSHORE CONDITIONS THROUGH THE FIRST PART OF THE
WEEKEND. THE FORECAST CALLS FOR THESE CONDITIONS TO CONTINUE THROUGH
THE MARTIN LUTHER KING HOLIDAY...HOWEVER THE CERTAINTY OF THIS
FORECAST IS NOW IN DOUBT. WE WILL KEEP AN EYE ON IT.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH (SEE LAXFFALOX).
FLOOD ADVISORY (SEE LAXFLSLOX)
WINTER STORM WARNING (SEE LAXWSWLOX).
SMALL CRAFT ADVISORY (SEE LAXCWFLOX).
FLOOD WARNING (SEE LAXFLWLOX).
FLASH FLOOD WARNING (SEE LAXFFWLOX).

&&

DANIELSON

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
600 AM PST MON JAN 10 2005

CAZ034>041-044>047-051>054-059-087-088-111400-
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 PST MON JAN 10 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA.

.DAY ONE... TODAY

RAIN AND THUNDERSTORMS WILL CONTINUE TODAY TO PRODUCE VERY HAZARDOUS
WEATHER.

* FLASH FLOOD WARNING........SEE WGUS56 KLOX - FFWLOX FOR DETAILS *

* FLOOD WARNING..............SEE WGUS46 KLOX - FLWLOX FOR DETAILS *

* RIVER FLOOD WARNING........SEE WGUS46 KLOX - FLWLOX FOR DETAILS *

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

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

* FLOOD ADVISORY.............SEE WGUS86 KLOX - FLSLOX FOR DETAILS *

.DAYS TWO THROUGH SEVEN... TUESDAY THROUGH SUNDAY

A VIGOROUS COLD FRONT WILL SWEEP THROUGH THE AREA TUESDAY MORNING.
THIS WILL DROP THE SNOW LEVEL TO 4500 FEET AND GREATLY INCREASE THE
THREAT OF HAZARDOUS WINTER WEATHER. BELOW THE SNOW LEVEL HEAVY RAINS
WILL CONTINUE THE THREAT OF HAZARDOUS HYDROLOGICAL CONDITIONS.

HAZARDOUS WEATHER IS NOT FORECAST WEDNESDAY THROUGH SUNDAY.

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

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

.SPOTTER INFORMATION STATEMENT...

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

RORKE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
815 PM PST MON JAN 10 2005

CAZ034>041-044>047-051>054-059-087-088-111400-
ANTELOPE VALLEY-CATALINA ISLAND-CUYAMA VALLEY-
LOS ANGELES COUNTY COAST INCLUDING DOWNTOWN LOS ANGELES-
LOS ANGELES COUNTY MOUNTAINS EXCLUDING THE SANTA MONICA RANGE-
LOS ANGELES COUNTY VALLEYS-SAN LUIS OBISPO COUNTY CENTRAL COAST-
SAN LUIS OBISPO COUNTY INTERIOR VALLEYS-
SAN LUIS OBISPO COUNTY MOUNTAINS-SANTA BARBARA COUNTY CENTRAL COAST-
SANTA BARBARA COUNTY MOUNTAINS-SANTA BARBARA COUNTY SOUTH COAST-
SANTA CLARITA VALLEY-SANTA MONICA MOUNTAINS RECREATIONAL AREA-SANTA
YNEZ VALLEY-VENTURA COUNTY COAST-VENTURA COUNTY COASTAL
VALLEYS-VENTURA COUNTY INTERIOR VALLEYS-VENTURA COUNTY MOUNTAINS-
815 PM PST MON JAN 10 2005

...ANOTHER ROUND OF SIGNIFICANT WEATHER EXPECTED ACROSS SOUTHWESTERN
   CALIFORNIA TONIGHT AND TUESDAY...

THE LARGE UPPER LEVEL LOW WHICH HAS LINGERED OFF THE WEST COAST
FOR THE PAST SEVERAL DAYS WILL SEND YET ANOTHER STRONG IMPULSE
INTO CENTRAL AND SOUTHERN CALIFORNIA OVERNIGHT AND TUESDAY.
RAIN WAS ALREADY INCREASING IN COVERAGE AND INTENSITY ACROSS
SAN LUIS OBISPO AND SANTA BARBARA COUNTIES THIS EVENING...WITH
LOCALLY HEAVY RAIN BEING REPORTED IN SOME AREAS. RAIN...HEAVY
AT TIMES...IS EXPECTED TO SPREAD BACK INTO VENTURA AND LOS
ANGELES COUNTIES OVERNIGHT.

THE ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE ACROSS THE
AREA LATE TONIGHT AND TUESDAY...AND THE THREAT OF THUNDERSTORMS
WILL INCREASE. SOME OF THESE THUNDERSTORMS WILL PRODUCE
INTENSE RAINFALL...WITH RATES EXCEEDING ONE INCH PER HOUR...
STRONG WINDS...SMALL HAIL...AND POSSIBLY EVEN SOME BRIEF
TORNADOES AND WATERSPOUTS.

RAIN AND THUNDERSTORMS WILL DECREASE FROM NORTHWEST TO
SOUTHEAST ACROSS THE AREA TUESDAY...WITH JUST SCATTERED
SHOWERS IN MOST AREAS BY TUESDAY NIGHT. SHOWERS WILL FINALLY
END ACROSS THE AREA LATE TUESDAY NIGHT...AND DRY WEATHER
IS EXPECTED THROUGH AT LEAST FRIDAY.

PLEASE REFER TO THE PUBLIC INFORMATION STATEMENT (LAXPNSLOX)
FOR A COMPREHENSIVE LIST OF ALL CURRENT WARNINGS...WATCHES
AND ADVISORIES ACROSS THE AREA.

FOR ADDITIONAL WEATHER INFORMATION...CHECK OUR WEB SITE AT
HTTP://WWW.WEATHER.GOV/LOSANGELES.

BRUNO