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

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000
FXUS66 KMTR 190033
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
433 PM PST THU DEC 18 2014

.SYNOPSIS...A FEW LIGHT SHOWERS WILL CONTINUE TODAY. THE NEXT
SYSTEM TO BRING RAIN BACK TO THE AREA WILL MOVE IN LATE THIS
EVENING THROUGH FRIDAY. AFTER SOME RESIDUAL SHOWERS ON
SATURDAY...A RIDGE OF HIGH PRESSURE WILL BUILD OVER THE WEST COAST
RESULTING IN A DRYING TREND THROUGH AT LEAST MOST OF NEXT WEEK.

&&

.DISCUSSION...AS OF 3:00 PM PST THURSDAY...RADAR HAS CONTINUED TO
PICK UP A FEW ECHOS INTO THE AFTERNOON HOURS WITH A HANDFUL OF
GAUGES PICKING UP LIGHT AMOUNTS OF PRECIPITATION TODAY. SHOWERS
WILL LIKELY CONTINUE INTO THE OVERNIGHT HOURS IN ADVANCE OF MORE
SUBSTANTIAL RAIN AS OUR FINAL SYSTEM FOR THE WEEK TAKES AIM ON OUR
CWA.

RAIN WILL BE ON THE INCREASE FOR THE EVENING AND OVERNIGHT
HOURS AND START AS WARM FRONTAL RAIN BEFORE SWITCHING TO
WIDESPREAD MODERATE RAINFALL FRIDAY MORNING INTO THE AFTERNOON AS
A WEAK SURFACE LOW SKIRTS DOWN THE COAST. APPEARS THAT THE MORNING
COMMUTE FOR FRIDAY WILL BE WET FOR ALMOST ALL SPOTS WITH THE
POTENTIAL FOR MODERATE RAINFALL HITTING THE NORTH BAY CLOSE TO SUNRISE...DOWN
TO SF BAY LATE IN THE MORNING...AND TO MONTEREY BAY AND SOUTH BY
NOON TO EARLY AFTERNOON. WINDS WILL ALSO PICK UP A BIT ESPECIALLY
OVER THE HILLS. SPOTS ABOVE 1000 FEET CLOUD SEE LOCAL GUSTS OVER
30 MPH WITH SPEEDS GENERALLY 15 TO 25 MPH.

BEHIND THE SYSTEM THE RAIN WILL SWITCH OVER TO SCATTERED SHOWERS
AT LEAST INTO FRIDAY EVENING. RAINFALL TOTALS BY THAT POINT WILL BE
MOSTLY A THIRD TO TWO THIRDS FOR URBAN SPOTS WILL LOCALLY MORE
THAN 1 INCH FOR THE NORTH BAY. POSSIBLE WE COULD SEE SOME URBAN
AND SMALL STREAM ISSUES AND MINOR DEBRIS FLOWS IF THE HEAVIER RAIN
HITS ANY OF OUR RECENT PROBLEM AREAS. STILL A CHANCE FOR SOME
RESIDUAL SHOWERS INTO SATURDAY OVER THE NORTH BAY WHILE MOST OTHER LOCATIONS
SHOULD BE DRY BEFORE SATURDAY MORNING.

A RIDGE OF HIGH PRESSURE WILL BUILD BACK INTO OUR REGION STARTING
OVER THE WEEKEND ALLOWING FOR DRIER AND EVENTUALLY WARMER WEATHER
TO RETURN. THE STORM TRACK SHOULD STAY TO THE NORTH AT LEAST
THROUGH CHRISTMAS DAY.

&&

.AVIATION...AS OF 4:15 PM PST THURSDAY...FOR 00Z TAFS. DOPPLER
RADAR SHOWS LITTLE IF ANY RETURNS ACROSS THE REGION HOWEVER
SHOWERS MOVING IN BELOW THE RADAR CONTINUE TO FALL OVER THE NORTH
BAY. HAVE INCLUDED A TEMPO GROUP THROUGH 04Z OVER KSTS. OTHERWISE
INCREASING CLOUDS EXPECTED THROUGH THE FORECAST AS THE NEXT SYSTEM
APPROACHES. LIGHT SOUTHEAST WINDS WILL CONTINUE AHEAD OF THE
FRONTAL SYSTEM. LIGHT WARM FRONTAL RAIN IS EXPECTED TO BEGIN
OVERNIGHT WITH STEADY RAIN EXPECTED FRIDAY MORNING.

VICINITY OF KSFO...MAINLY VFR CIGS THROUGH THIS EVENING WITH
CIGS LOWERING TO MVFR AROUND 2000-2500 FEET AFTER MIDNIGHT. LIGHT
SOUTHEAST WINDS EXPECTED TO CONTINUE AHEAD OF THE APPROACHING
FRONT. WINDS WILL GRADUALLY VEER TO THE WEST AFTER FRONTAL PASSAGE
FRIDAY AFTERNOON.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...MAINLY VFR CIGS THROUGH THIS EVENING WITH
CIGS LOWERING TO MVFR AROUND 3000 FEET AFTER MIDNIGHT. LIGHT
SOUTHEAST WINDS EXPECTED TO CONTINUE AHEAD OF THE APPROACHING
FRONT. WINDS WILL GRADUALLY VEER TO THE WEST AFTER FRONTAL PASSAGE
FRIDAY AFTERNOON.

&&

.MARINE...AS OF 3:00 PM PST THURSDAY...SOUTHERLY WINDS THIS
EVENING AHEAD OF AN APPROACHING FRONT THAT WILL SPREAD RAIN OVER
THE NORTHERN WATERS TONIGHT. RAIN WILL SPREAD SOUTHWARD FRIDAY
MORNING AS A COLD FRONT PASSES THROUGH THE WATERS WITH WINDS
TURNING WESTERLY. BEHIND THE FRONT LARGE NW SWELLS WILL BUILD INTO
THE WEEKEND. BUILDING HIGH PRESSURE WILL BRING LIGHTER WINDS OVER
THE WEEKEND. THE COMBINATION OF LARGE SEAS AND UNUSUALLY HIGH
TIDES WILL CREATE HAZARDOUS SEAS OVER THE OCEAN AND NEAR THE COAST
FOR MUCH OF THE WEEKEND.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...NONE.

&&

$$

PUBLIC FORECAST: BELL
AVIATION: CW
MARINE: RWW

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