Flooding and Coastal Flood in California, December 2 to 3, 2014

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
406 AM PST TUE DEC 2 2014

.SYNOPSIS...UNSETTLED WEATHER AND WIDESPREAD RAINFALL WILL
CONTINUE THROUGH WEDNESDAY AS AN UPPER LEVEL STORM SYSTEM IMPACTS
THE REGION.

&&

.DISCUSSION...AS OF 3:40 AM PST TUESDAY...WIDESPREAD RAIN AND
EMBEDDED SHOWERS CURRENTLY MOVING INTO MUCH OF THE REGION THIS
MORNING AS A SERIES OF SHORT-WAVE DISTURBANCES APPROACH THE COAST.
RAINFALL RATES HAVE INCREASED OVER THE PAST COUPLE OF HOURS...AS
EXPECTED WITH THE DISTURBANCES INTERACTING WITH DEEPER MOISTURE
ADVECTING IN FROM THE SOUTHWEST. CLOUD TOPS CAN ALSO BE SEEN
COOLING VIA THE LATEST IR SATELLITE IMAGERY AND REGIONAL RADARS
SHOWING ENHANCEMENT IN PRECIPITATION OFFSHORE. THE SHORT-RANGE
FORECAST MODELS ARE ALSO PROJECTING THE UPPER LEVEL JET TO
STRENGTHEN OVER THE CENTRAL COAST THROUGH THE MORNING. EXPECTING
PRECIPITATION TO BE MODERATE (LOCALLY HEAVY AT TIMES) THROUGH THE
EARLY AFTERNOON HOURS...ESPECIALLY OVER THE SANTA CRUZ AND SANTA
LUCIA MOUNTAINS. THERE ALSO APPEARS TO BE A BREAK IN THUNDERSTORMS
EARLY THIS MORNING...YET THE POTENTIAL WILL CONTINUE OFFSHORE THIS
MORNING. THE THREAT FOR THUNDERSTORMS WILL INCREASE SLIGHTLY THIS
AFTERNOON AND TONIGHT WITH LIFTED INDEX VALUES FORECAST TO BE
BETWEEN -2C AND -5C IN COMBINATION WITH INCREASED CAPE AS THE MAIN
MID/UPPER LOW MOVES CLOSER TO THE REGION.

WHILE PRECIPITATION MAY LET UP SLIGHTLY THIS EVENING...ANOTHER
SHORT-WAVE DISTURBANCE JUST AHEAD OF THE MAIN UPPER LEVEL SYSTEM IS
SET TO IMPACT THE REGION LATE TONIGHT INTO EARLY WEDNESDAY MORNING.
THIS SHOULD ONCE AGAIN ENHANCE PRECIPITATION RATES OVER THE ENTIRE
REGION. THIS IS ALSO WHEN SURFACE WIND SPEEDS ARE EXPECTED TO
INCREASE AND BECOME GUSTY AT TIMES WHEN THE DEEP SURFACE LOW
APPROACHES THE COAST. WINDS ARE NOT EXPECTED TO REACH ADVISORY
LEVELS HOWEVER...MAINLY DUE TO THE WEAKENING NATURE OF THE SURFACE
LOW AS IT BEGINS TO EJECT NORTHWARD INTO NORTHERN CALIFORNIA
WEDNESDAY AFTERNOON.

RAINFALL AMOUNTS THROUGH WEDNESDAY ARE FORECAST TO BE IMPRESSIVE
OVER THE COASTAL RANGES WHERE THE SHORT-TERM...HIGH RESOLUTION
MODELS SHOW QPF AMOUNTS BETWEEN 3-5 INCHES (ISOLATED AMOUNTS UPWARDS
OF 6 INCHES IN THE SANTA CRUZ AND SANTA LUCIA COASTAL RANGES). THIS
WOULD LIKELY CAUSE SOME HYDRO CONCERNS IN THESE AREAS AND INCREASE
THE POTENTIAL FOR ISSUES OVER THE BURN SCARS IN THE BIG SUR REGION.
PLEASE SEE THE LATEST HYDROLOGIC OUTLOOK (FGUS76 KMTR - ESFMTR) FOR
DETAILED IMPACTS. MEANWHILE...STORM TOTAL RAINFALL AMOUNTS IN THE
URBAN AREAS ARE LIKELY TO RANGE BETWEEN 1 TO 2 INCHES.

SHOWERS WILL DIMINISH IN COVERAGE WEDNESDAY NIGHT INTO THURSDAY WHEN
THE MID/UPPER LEVEL LOW LIFTS NORTHWARD AND MOVES AWAY FROM THE
REGION. WITH THAT SAID...LINGERING SHOWERS WILL CONTINUE TO BE
POSSIBLE THROUGH LATE WEEK AND INTO THE WEEKEND WITH MOIST SOUTHWEST
FLOW OVER THE REGION AND THE PRESENCE OF A LONG-WAVE TROUGH ALOFT.
HOWEVER...MOST LOCATIONS ARE FORECAST TO REMAIN DRY AND WIDESPREAD
RAINFALL IS NOT EXPECTED FOR LATE IN THE FORECAST PERIOD AT THIS
TIME. THIS PATTERN WILL ALSO CARRY OVER INTO EARLY NEXT WEEK WITH NO
CLEAR INDICATIONS OF ANOTHER SIGNIFICANT STORM SYSTEM OR A STRONG
BUILDING OF AN UPPER LEVEL RIDGE.

&&

AVIATION...AS OF 3:45 PM PST TUESDAY...TROPICAL MOISTURE BEING
DRAWN OVER THE REGION BY A LOW PRESSURE SYSTEM CIRCULATING OFF THE
WEST COAST WILL RESULT IN WET RUNWAYS...MODERATE SOUTHEASTERLY
WINDS AND DECREASED VISIBILITY ACROSS AREA TERMINALS THIS MORNING.
INSTABILITY ASSOCIATED WITH THE APPROACHING LOW WILL RESULT IN A
CHANCE OF SCATTERED THUNDERSTORMS AFTER 21Z TODAY. VFR CIGS ARE
EXPECTED TO LOWER TO MVFR THIS AFTERNOON WITH PASSING SHOWERS AND
THUNDERSTORMS. WET UNSETTLED WEATHER WILL CONTINUE THROUGH THE
FORECAST PERIOD.

VICINITY OF KSFO....VFR CIGS AND RAIN EXPECTED TO CONTINUE THROUGH
THE MORNING. MVFR CIGS AND VSBYS BETWEEN 3-5 MILES EXPECTED WITH
PERIODS OF RAIN. SCATTERED THUNDERSTORMS EXPECTED AFTER 21Z
THROUGH THIS EVENING. LIGHT TO MODERATE EAST SOUTHEAST WINDS
EXPECTED THROUGH THE PERIOD.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR CIGS AND RAIN EXPECTED TO
CONTINUE THROUGH THE MORNING. MVFR CIGS AND VSBYS BETWEEN 3-5
MILES EXPECTED WITH PERIODS OF RAIN. SCATTERED THUNDERSTORMS
EXPECTED AFTER 21Z THROUGH THIS EVENING. EAST-SOUTHEAST WINDS 7-15 KT
INCREASING TO 15-20 KT WITH GUSTS TO 30 KT AFTER 18Z AT SNS.

&&

.MARINE...AS OF 2:12 AM PST TUESDAY...A 991 MB LOW CENTERED 700 NM
WEST OF MONTEREY WILL ROTATE IN TOWARD THE COAST TODAY BRINGING
WITH IT MODERATE TO LOCALLY GUSTY SOUTHEASTERLY WINDS...RAIN AND
SCATTERED THUNDERSTORMS TO THE COASTAL WATERS. SHOWERS WITH
SCATTERED THUNDERSTORMS ARE EXPECTED TO CONTINUE THROUGH TONIGHT
AND WEDNESDAY. A MOIST SOUTHWEST FLOW WILL KEEP A CHANCE OF
SHOWERS GOING THROUGH THURSDAY.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...SCA...SF BAY NORTH OF THE BAY BRIDGE UNTIL 3 PM
             SCA...SF BAY SOUTH OF THE BAY BRIDGE UNTIL 3 PM
             SCA...PT REYES TO PIGEON PT 0-10 NM UNTIL 3 PM
             SCA...PIGEON PT TO PT PINOS 0-10 NM UNTIL 3 PM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM UNTIL 3 PM
             SCA...PT REYES TO PIGEON PT 10-60 NM UNTIL 3 PM
             SCA...PIGEON PT TO PT PINOS 10-60 NM UNTIL 3 PM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM UNTIL 3 PM
             SCA...PT ARENA TO PT REYES 0-10 NM
             SCA...PT ARENA TO PT REYES 10-60 NM
             SCA...MONTEREY BAY UNTIL 3 PM

&&

PUBLIC FORECAST: RGASS
AVIATION/MARINE: CW

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HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
512 PM PST MON DEC 1 2014

CAZ006-505>513-516>518-528>530-030115-
SAN FRANCISCO-
COASTAL NORTH BAY...INCLUDING POINT REYES NATIONAL SEASHORE-
NORTH BAY INTERIOR VALLEYS-NORTH BAY MOUNTAINS-
SAN FRANCISCO BAY SHORELINE-SAN FRANCISCO PENINSULA COAST-
EAST BAY INTERIOR VALLEYS-EAST BAY HILLS AND DIABLO RANGE-
SANTA CRUZ MOUNTAINS-SANTA CLARA VALLEY...INCLUDING SAN JOSE-
SOUTHERN SALINAS VALLEY...ARROYO SECO...AND LAKE SAN ANTONIO-
SANTA LUCIA MOUNTAINS AND LOS PADRES NATIONAL FOREST-
MOUNTAINS OF SAN BENITO AND INTERIOR MONTEREY COUNTY INCLUDING
PINNACLES NATIONAL PARK-
NORTHERN SALINAS VALLEY...HOLLISTER VALLEY...AND CARMEL VALLEY-
NORTHERN MONTEREY BAY-SOUTHERN MONTEREY BAY AND BIG SUR COAST-
512 PM PST MON DEC 1 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SAN FRANCISCO BAY AREA AND
MONTEREY BAY AREA.

.DAY ONE...MONDAY NIGHT

ISOLATED LIGHT SHOWERS WILL CONTINUE THROUGH EARLY MONDAY
AFTERNOON. OTHERWISE MOSTLY DRY CONDITIONS ARE EXPECTED THROUGH
MONDAY EVENING. RAIN WILL BEGIN TO MOVE ASHORE LATE MONDAY NIGHT
AS THE NEXT STORM SYSTEM APPROACHES THE COAST.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

RAIN WILL OVERSPREAD THE AREA ON TUESDAY MORNING AND WILL BE HEAVY AT
TIMES...PARTICULARLY IN THE SANTA LUCIA MOUNTAINS OF MONTEREY
COUNTY...BUT POSSIBLY IN THE SANTA CRUZ MOUNTAINS AS WELL AND
LOCALLY ELSEWHERE. RAINFALL WILL DIMINISH SOMEWHAT ON TUESDAY
AFTERNOON AND EVENING. WIDESPREAD SHOWER ACTIVITY WILL THEN
DEVELOP TUESDAY NIGHT AND CONTINUE THROUGH WEDNESDAY EVENING.
BRIEF HEAVY RAIN IS LIKELY WITH THESE SHOWERS. IN
ADDITION...ISOLATED THUNDERSTORMS ARE POSSIBLE FROM TUESDAY
THROUGH WEDNESDAY. THUNDERSTORM CHANCES ARE HIGHEST NEAR THE
COAST. MINOR URBAN AND SMALL STREAM FLOODING MAY OCCUR FROM
TUESDAY THROUGH WEDNESDAY.

IN ADDITION...LOCALLY STRONG AND GUSTY SOUTHERLY WINDS ARE
FORECAST TO DEVELOP NEAR THE COAST BY LATE MONDAY NIGHT. THESE
GUSTY WINDS WILL THEN INCREASE AND DEVELOP FARTHER INLAND ON
TUESDAY. WINDS WILL EASE SOMEWHAT ON TUESDAY AFTERNOON AND
EVENING...BUT THEN INCREASE ONCE AGAIN LATE TUESDAY NIGHT INTO
WEDNESDAY. STRONGEST WINDS ARE EXPECTED TO BE NEAR THE COAST AND
IN THE HILLS WHERE GUSTS UP TO 40 MPH ARE LIKELY ON TUESDAY AND
AGAIN ON WEDNESDAY. WINDS MAY BRING DOWN TREES AND RESULT IN POWER
OUTAGES.

PLEASE SEE THE LATEST AREA FORECAST DISCUSSION FOR MORE
INFORMATION.

.SPOTTER INFORMATION STATEMENT...

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