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

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000
FXUS66 KMTR 191310 CCA
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
403 AM PST FRI DEC 19 2014

.SYNOPSIS...LIGHT TO OCCASIONALLY MODERATE RAIN WILL SPREAD SOUTH
AND EAST OVER THE AREA TODAY. SOME SHOWERS WILL LINGER INTO SATURDAY
BUT THIS WILL BE FOLLOWED BY A RIDGE OF HIGH PRESSURE BUILDING OVER
THE WEST COAST RESULTING IN A DRYING TREND THROUGH AT LEAST MOST OF
NEXT WEEK INCLUDING CHRISTMAS.

&&

.DISCUSSION...AS OF 3:10 AM PST FRIDAY...LIGHT RAIN SHOWERS HAVE
BEEN AFFECTING THE NORTH BAY SINCE LAST EVENING WITH WEAK
ECHOES ALSO MOVING ACROSS THE GREATER SAN FRANCISCO BAY AREA.
THESE LIGHT SHOWERS ARE ASSOCIATED WITH THE WARM FRONT AHEAD OF
THE MAIN SYSTEM STILL LOCATED TO THE NORTH AND WEST. MODELS BRING
THE MAIN COLD FRONTAL BAND OVER THE NORTH BAY DURING THE MORNING...
AND ACROSS THE SAN FRANCISCO AREA BY MIDDAY. THE FRONT IS PROGGED TO
WEAKEN AS IT PUSHES EAST AND SOUTH...SO THE BULK OF THE RAINFALL
IS EXPECTED TO FOCUS ON THE NORTH BAY. UP TO AN INCH OF RAIN TOTAL
IS POSSIBLE IN THE NORTH BAY MOUNTAINS WITH A THIRD TO THREE
QUARTERS OF AN INCH ELSEWHERE...HIGHER VALUES NORTH AND IN THE
COASTAL HILLS.

SHOWERS WILL TAPER OFF OVERNIGHT WITH A FEW RESIDUAL SHOWERS
LINGERING INTO SATURDAY. HIGH PRESSURE ALOFT IS THEN FORECAST TO
BUILD OVER THE EASTERN PACIFIC AND SPREAD OVER THE COAST. THIS
WILL PUSH THE STORM TRACK TO THE NORTH AND BRING IN A WARMING AND
DRYING TREND TO THE DISTRICT THAT SHOULD PERSIST THROUGH AT LEAST
MIDWEEK. MEDIUM RANGE MODELS STILL INDICATE THE POSSIBILITY OF
BRINGING AN INSIDE SLIDER TYPE TROUGH ACROSS NORTHERN CALIFORNIA
AND NEVADA BY LATE WEDNESDAY NIGHT AND INTO THURSDAY. HOWEVER THE
LATEST MODEL SOLUTIONS GENERALLY ARE KEEPING THE PRECIP CHANCES
MORE EAST AND NORTH...SO FOR NOW...KEEPING THE EXTENDED PORTION OF
THE FORECAST DRY.

&&

.AVIATION...AS OF 3:55 AM PST FRIDAY...FOR 12Z TAFS. WARM FRONTAL
RAIN IS BEGINNING TO SPREAD SOUTHWARD ACROSS THE BAY AREA.
STEADIER RAIN IS EXPECTED TO REACH THE BAY AREA THIS AFTERNOON.
LIGHT SOUTHEAST WINDS WILL CONTINUE AHEAD OF THE FRONTAL SYSTEM.

VICINITY OF KSFO...VFR CIGS ARE ANTICIPATED TO LOWER TO MVFR
AROUND 3000 FEET. LIGHT SOUTHEAST WINDS EXPECTED TO CONTINUE
AHEAD OF THE APPROACHING FRONT. WINDS WILL GRADUALLY VEER
WESTERLY AFTER FRONTAL PASSAGE THIS AFTERNOON.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

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

&&

.MARINE...AS OF 2:55 AM PST FRIDAY...SOUTHERLY WINDS WILL
CONTINUE TONIGHT AHEAD OF AN APPROACHING FRONT THAT WILL SPREAD
RAIN OVER THE COASTAL WATERS THROUGH THE DAY. BEHIND THE FRONT
WINDS WILL TURN WESTERLY AND 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...
     .TDAY...HIGH SURF ADVISORY...NORTH BAY COAST AFTER 3 PM
             SCA...PT ARENA TO PT REYES 0-10 NM FROM 3 PM
             SCA...PT ARENA TO PT REYES 10-60 NM FROM 3 PM
             SCA...PT REYES TO PIGEON PT 10-60 NM FROM 3 PM
             SCA...PIGEON PT TO PT PINOS 10-60 NM FROM 3 PM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM FROM 3 PM

&&

$$

PUBLIC FORECAST: SIMS
AVIATION/MARINE: CW

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