HAZARDOUS WEATHER OUTLOOK
Issue Date: 1122 PM PST THU DEC 10 2009
Expiration: 600 AM PST FRI DEC 11 2009
THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA.
.DAY ONE... TODAY
MODERATE RAINFALL WILL AFFECT MUCH OF LOS ANGELES COUNTY OVERNIGHT
WITH THE POSSIBILITIES OF MINOR DEBRIS FLOWS ACROSS THE BURN AREAS
OF LOS ANGELES COUNTY. A STORM SYSTEM WILL CONTINUE TO MOVE ACROSS
THE AREA OVERNIGHT...BRINGING RAIN AND SNOW TO CENTRAL AND SOUTHERN
CALIFORNIA. AT THIS TIME...RAINFALL AMOUNTS ARE EXPECTED TO RANGE
BETWEEN 0.25 AND 0.75 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE IN
THE FOOTHILLS AND MOUNTAINS THROUGH FRIDAY MORNING.SNOW LEVELS WILL
REMAIN AROUND 6000 FEET OR HIGHER WITH 3 TO6 INCHES OF SNOWFALL
EXPECTED ABOVE 6000 FEET. AS THIS STORM MOVES THROUGH...IT MAY
PRODUCE AN ISOLATED THUNDERSTORM TONIGHT OVER THE CENTRAL
COAST.ACROSS THE COASTAL WATERS...THERE WILL ALSO BE A THUNDERSTORM
THREAT. ANY THUNDERSTORMS THAT DEVELOP TONIGHT WILL BE CAPABLEOF
PRODUCING A WATERSPOUT. IN ADDITION...A LARGE WESTERLY SWELL WILL
CONTINUE TO DISSIPATE THROUGH TONIGHT...PRODUCING HIGHER THAN NORMAL
SURF CONDITIONS ALONG THE BEACHES AND DANGEROUS RIP CURRENTS.
* FLOOD ADVISORY.............SEE WGUS86 KLOX - FLSLOX FOR DETAILS *
* WINTER WEATHER ADVISORY....SEE WWUS46 KLOX - WSWLOX FOR DETAILS *
* HIGH RIP CURRENT RISK......SEE FZUS56 KLOX - SRFLOX FOR DETAILS *
* MARINE WEATHER STATEMENT...SEE FZUS76 KLOX - MWSLOX FOR DETAILS *
* SPECIAL WEATHER STATEMENT..SEE WWUS86 KLOX - SPSLOX FOR DETAILS *
.DAYS TWO THROUGH SEVEN... FRIDAY THROUGH WEDNESDAY
MODERATE RAINFALL WILL AFFECT MUCH OF LOS ANGELES COUNTY OVERNIGHT
WITH THE POSSIBILITIES OF MINOR DEBRIS FLOWS ACROSS THE BURN AREAS
OF LOS ANGELES COUNTY. A MOIST AND UNSTABLE WESTERLY FLOW WILL
CONTINUE ACROSS THE AREA THROUGH FRIDAY EVENING...BRINGING A
CONTINUED THREAT OF SHOWERS TO THE ENTIRE AREA. BEGINNING LATE
FRIDAY NIGHT THROUGH SUNDAY MORNING...A SECOND ANDMORE POWERFUL
STORM SYSTEM IS EXPECTED TO MOVE ACROSS THE AREA.AT THIS TIME...THIS
STORM IS EXPECTED TO PRODUCE MORE SIGNIFICANTRAINFALL
TOTALS...GENERALLY 0.50" TO 1.50" INCHES ACROSS COASTALAREAS TO
1.50" TO 2.50" INCHES IN THE FOOTHILLS AND MOUNTAINS. SNOWLEVELS
WILL REMAIN AROUND 6000 FEET THROUGH SATURDAY EVENING...BEFORE
DROPPING TO AROUND 5500 FEET ON SUNDAY. ALONG WITH THEPOTENTIAL
SIGNIFICANT SNOWFALL...GUSTY SOUTHERLY WINDS ARE EXPECTEDWHICH MAY
PRODUCE HAZARDOUS WINTER WEATHER CONDITIONS ACROSS THEMOUNTAINS.
GIVEN THE RAINFALL AMOUNTS EXPECTED AND THE POTENTIALRAINFALL
RATES...THERE WILL BE CONCERN ABOUT MUD AND DEBRIS FLOWSOVER THE
RECENT BURN AREAS.
* WINTER WEATHER ADVISORY....SEE WWUS46 KLOX - WSWLOX FOR DETAILS *
* MARINE WEATHER STATEMENT...SEE FZUS76 KLOX - MWSLOX 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.
SPECIAL WEATHER STATEMENT
Issue Date: 332 PM PST THU DEC 10 2009
Expiration: 600 AM PST FRI DEC 11 2009
...TWO STORMS TO AFFECT CENTRAL AND SOUTHERN CALIFORNIA THROUGH
SUNDAY...
A PERIOD OF WET WEATHER IS EXPECTED ACROSS CENTRAL AND SOUTHERN
CALIFORNIA AS TWO DIFFERENT STORMS MOVE ACROSS THE AREA.
THE FIRST STORM IS CURRENTLY MOVING INTO SAN LUIS OBISPO AND
SANTA BARBARA COUNTIES THIS AFTERNOON AND WILL AFFECT VENTURA AND
LOS ANGELES COUNTIES TONIGHT AND FRIDAY MORNING. WITH THIS STORM
SYSTEM...MODERATE RAINFALL AMOUNTS ARE EXPECTED AT TIMES THROUGH
FRIDAY MORNING...BUT THERE IS THE POTENTIAL FOR BRIEF HEAVY SHOWERS
AND EVEN A THUNDERSTORM OR TWO CANNOT BE RULED OUT. AT THIS TIME...
THE BEST THUNDERSTORM POTENTIAL WILL BE ACROSS THE CENTRAL COAST
THIS AFTERNOON AND EVENING...THEN THE ENTIRE COASTAL WATERS TONIGHT.
RAINFALL AMOUNTS ARE EXPECTED TO RANGE BETWEEN ONE QUARTER AND THREE
QUARTERS OF AN INCH OF RAINFALL...WITH LOCAL AMOUNTS AROUND ONE
INCH POSSIBLE IN FAVORED UPSLOPE AREAS AND NEAR HEAVIER SHOWERS OR
THUNDERSTORMS. SNOW LEVELS WITH THIS STORM ARE ANTICIPATED TO REMAIN
ABOVE 6000 FEET...SO THE RESORT AREAS WILL LIKELY RECEIVE SEVERAL
INCHES OF SNOWFALL. AT THIS TIME SNOWFALL ACCUMULATIONS OF 3 TO 6
INCHES ARE EXPECTED ABOVE 6000 FEET ACROSS THE MOUNTAINS OF
VENTURA AND LOS ANGELES COUNTIES...WHERE A WINTER WEATHER ADVISORY
HAS BEEN POSTED (PLEASE REFER TO LAXWSWLOX FOR THE LATEST ON THE
SNOWFALL POTENTIAL).
ANY THUNDERSTORMS THAT DEVELOP OVER THE COASTAL WATERS WILL BE
CAPABLE OF PRODUCING WATERSPOUTS (PLEASE REFER TO LAXMWSLOX FOR
THE LATEST MARINE INFORMATION).
DURING THE DAY ON FRIDAY...THERE WILL BE A RELATIVE PRECIPITATION
LULL AS THE AREA WILL BE BETWEEN STORM SYSTEMS. HOWEVER...A MOIST
AND UNSTABLE WESTERLY FLOW WILL PRODUCE SCATTERED SHOWERS THROUGH
FRIDAY EVENING.
LATE FRIDAY NIGHT INTO SATURDAY NIGHT...THE SECOND...AND MORE
POTENT...STORM SYSTEM WILL MOVE THROUGH CENTRAL AND SOUTHERN
CALIFORNIA. THIS SECOND STORM SYSTEM IS ANTICIPATED TO PRODUCE
MORE RAINFALL DUE TO A SUBTROPICAL MOISTURE SOURCE AND STRONG
SOUTH TO SOUTHWEST FLOW AHEAD OF THE STORM. AT THIS TIME... THE
PERIOD OF HEAVIEST RAINFALL IS ANTICIPATED TO BE LATE SATURDAY
AFTERNOON AND EVENING...WITH THE PRECIPITATION TAPERING OFF
THROUGH THE DAY ON SUNDAY. PRELIMINARY RAINFALL ESTIMATES WITH
THIS SECOND SYSTEM ARE EXPECTED TO RANGE FROM 0.50 TO 1.50 INCHES
ACROSS COASTAL AND VALLEY AREAS TO 1.50 TO 2.50 INCHES IN THE
FOOTHILLS AND MOUNTAINS. SNOW LEVELS WITH THIS STORM ARE EXPECTED
TO REMAIN RELATIVELY HIGH THROUGH SATURDAY NIGHT...GENERALLY ABOVE
6000 FEET...DUE TO THE SOUTHERLY WINDS. HOWEVER ON SUNDAY...THE
SNOW LEVELS SHOULD DROP TO AROUND 5500 FEET AS SOME COLDER AIR
FILTERS INTO THE AREA. SIGNIFICANT SNOWFALL ACCUMULATIONS WILL BE
POSSIBLE ABOVE 6000 FEET. SOUTHERLY WINDS BETWEEN 25 AND 35 MPH
WITH GUSTS TO 50 MPH CAN BE EXPECTED ON SATURDAY AND SATURDAY
NIGHT...WITH POSSIBLE DANGEROUS WINTER STORM CONDITIONS IN THE
MOUNTAINS. A WINTER STORM WATCH MAY BE REQUIRED FOR THIS SECOND
SYSTEM.
WITH RAIN CURRENTLY IN THE FORECAST...THERE IS CONCERN ABOUT THE
RECENT BURN AREAS DUE TO POSSIBLE MUD AND DEBRIS FLOWS. AT THIS
TIME...THE FIRST SYSTEM TODAY AND TONIGHT IS NOT ANTICIPATED TO
CAUSE ANY SIGNIFICANT PROBLEMS AS HOURLY RAINFALL RATES ARE NOT
EXPECTED TO EXCEED CRITICAL USGS THRESHOLDS. WITH THE SECOND STORM
ON SATURDAY AND SATURDAY NIGHT...THERE IS MORE CONCERN ABOUT
POTENTIAL MUD AND DEBRIS FLOWS. THE FORECAST PRECIPITATION
TOTALS...AS WELL AS THE POTENTIAL FOR HIGHER HOURLY RAINFALL
RATES...MAY REQUIRE THE ISSUANCE OF FLASH FLOOD WATCHES FOR THE
BURN AREAS.
THIS WILL BE A RAPIDLY DEVELOPING WEATHER SITUATION THE NEXT FEW
DAYS ACROSS CENTRAL AND SOUTHERN CALIFORNIA. STAY TUNED TO NOAA
WEATHER RADIO OR YOUR FAVORITE LOCAL NEWS SOURCE FOR THE LATEST
STATEMENTS CONCERNING THIS WEATHER SYSTEM.
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