Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

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000
FXUS66 KMTR 301630
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
930 AM PDT THU OCT 30 2014

.SYNOPSIS...COOLING IS EXPECTED TODAY AHEAD OF AN APPROACHING PACIFIC
COLD FRONT. THE COLD FRONT WILL SPREAD RAIN ACROSS THE ENTIRE
REGION LATE TONIGHT INTO FRIDAY. SHOWERS AND ISOLATED THUNDERSTORMS ARE
FORECAST FOR FRIDAY NIGHT INTO SATURDAY MORNING. DRY WEATHER WILL
RETURN SATURDAY NIGHT AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK
AS HIGH PRESSURE REBUILDS.

&&

.DISCUSSION...AS OF 9:30 AM PDT THURSDAY...IT WAS A MILD NIGHT
WITH MORNING TEMPERATURES RUNNING WARMER THAN YESTERDAY BY AS
MANY AS 10 DEGREES. SURFACE PRESSURE GRADIENTS ARE RELATIVELY
LIGHT...AND WITH HIGH CLOUDS TODAY...MILD TEMPERATURES ARE
EXPECTED. HIGHS TODAY ARE FORECAST FROM THE 60S TO LOWER 70S AT
THE COAST TO THE 80S INLAND...COOLER THAN YESTERDAY BUT STILL
MILD.

ALL EYES ARE ON THE APPROACHING WEATHER SYSTEM EXPECTED TO AFFECT
NORTHERN CALIFORNIA AS EARLY AS THIS EVENING. THE UPPER LOW IS
CURRENTLY LOCATED NEAR 50N/139W WITH THE ASSOCIATED FRONTAL BAND
ABOUT 475 MILES DUE WEST OF SAN FRANCISCO. THIS SYSTEM IS PROGGED
TO MOVE EASTWARD AND BRING RAIN TO THE NORTH BAY AREA BY LATE
THIS EVENING AND WIDESPREAD RAINFALL IS EXPECTED ACROSS OUR ENTIRE AREA
ON FRIDAY. AS THE UPPER LOW DROPS SOUTH AND THE COOL UNSTABLE
AIRMASS MOVES OVER NORTHERN CALIFORNIA...THUNDERSTORMS WILL BE
POSSIBLE ACROSS THE DISTRICT FRIDAY AFTERNOON. SHOWERS WILL
PERSIST INTO SATURDAY MORNING BEFORE THE STORM MOVES TO THE EAST
AND HIGH PRESSURE REBUILDS OVER THE STATE.

CLOUDS WILL MOVE ACROSS OUR AREA BY THIS EVENING AS THE COLD FRONT
NEARS AND OVERNIGHT RAIN WILL START ACROSS THE NORTH BAY AND
SPREAD TO THE SOUTH THROUGH FRIDAY IN COORDINATION WITH THE FRONT.
MODELS ARE GENERALLY IN GOOD AGREEMENT WITH THE TIMING AND BRING
THE MAIN BAND OF RAIN AND BREEZY CONDITIONS DOWN TO THE SAN FRANCISCO
BAY AREA LATE FRIDAY MORNING THROUGH EARLY AFTERNOON...AND TO SAN
JOSE AND MONTEREY BAY AREA BY FRIDAY AFTERNOON. RAINFALL AMOUNTS
COULD BE FAIRLY IMPRESSIVE FOR THIS TIME OF YEAR RANGING FROM
AROUND ONE TO TWO THIRDS OF AN INCH ACROSS URBAN LOCATIONS...WITH
HIGHER ELEVATION AREAS LOCALLY RECEIVING 1-2 INCHES.


&&

.AVIATION...AS OF 4:40 AM PDT THURSDAY...VFR CONDITIONS ARE
ANTICIPATED TO PREVAIL THROUGH THURSDAY NIGHT ACROSS AREA TERMINALS.
INCREASING HIGH CLOUDS ARE EXPECTED AHEAD OF AN APPROACHING
FRONTAL SYSTEM THAT WILL MOVE INTO THE REGION LATE THURSDAY NIGHT
INTO FRIDAY. SOUTHERLY WINDS WILL DEVELOP THURSDAY AFTERNOON AHEAD
OF THE APPROACHING COLD FRONT. PRECIPITATION WILL BEGIN WITH
ARRIVAL OF FRONT TOWARDS THE END OF THE 30-HOUR PERIOD FRIDAY
MORNING. MODERATE TO HIGH CONFIDENCE.

VICINITY OF KSFO...VFR CONDITIONS AND LIGHT WINDS ARE ANTICIPATED
THROUGH THE THE NEXT 30 HOURS. RAIN AND MVFR CIGS POSSIBLE AFTER
15Z FRIDAY.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR CONDITIONS AND LIGHT WINDS ARE
ANTICIPATED THROUGH THE FORECAST PERIOD.

&&

.MARINE...AS OF 08:45 AM PDT THURSDAY...LIGHT WIND AND SEAS TODAY
AHEAD OF AN APPROACHING COLD FRONT. WINDS WILL TURN SOUTHERLY
TONIGHT AS THE FRONT APPROACHES WITH RAIN DEVELOPING OVER THE
WATERS TONIGHT INTO FRIDAY. WINDS WILL TURN NW BY FRIDAY AFTERNOON
BUT IN GENERAL LIGHT WINDS ARE FORECAST WITH THE FRONTAL PASSAGE.
NW WINDS WILL INCREASE LATER FRIDAY NIGHT INTO SATURDAY ALONG WITH
A SLIGHT CHANCE OF THUNDERSTORMS AND BUILDING NW SEAS.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...NONE.

$$

PUBLIC FORECAST: SIMS
AVIATION: DRP/LARRY
MARINE: RWW

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