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

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000
FXUS66 KMTR 201236
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
436 AM PST SAT DEC 20 2014

.SYNOPSIS...SCATTERED SHOWERS WILL CONTINUE ACROSS OUR AREA TODAY
AND SLOWLY DIMINISH TONIGHT. THIS WILL BE FOLLOWED BY A RIDGE OF
HIGH PRESSURE BUILDING OVER THE WEST COAST RESULTING IN A DRYING
AND WARMING TREND THROUGH AT LEAST MOST OF NEXT WEEK.

&&

.DISCUSSION...AS OF 3:10 AM PST SATURDAY...SURPRISING NUMBER OF
SHOWERS OVERNIGHT WITH 12 HOUR RAINFALL TOTALS QUITE A BIT ABOVE
EXPECTATIONS. IN FACT...PORTIONS OF SANTA CRUZ COUNTY ARE WELL
OVER AN INCH AND ON THEIR WAY TO HITTING 1.5 INCHES. CURRENT RADAR
LOOP SHOWS BULK OF ACTIVITY STRETCHING IN A BAND FROM SANTA CRUZ
AND SAN MATEO COUNTIES NE THROUGH SANTA CLARA COUNTY. HRRR SEEMS
TO HAVE DONE A FAIRLY GOOD JOB WITH SHOWING THE EVOLUTION AND
TENDED TO FAVOR IT FOR THE SHORT TERM FORECAST. IT INDICATES THAT
SHOWERS WILL BE ON THE DECREASE THROUGH THE DAY ALTHOUGH ALL
LOCATIONS WILL HAVE AT LEAST A SHOT AT GETTING LIGHT RAINFALL.
POPS WERE PUSHED UP FOR VIRTUALLY ALL SPOTS AND MAY HAVE BE
INCREASED EVEN MORE IF THEY SHOWERS DO NOT START TO DISSIPATE
BEFORE SUNRISE. IN GENERAL RAINFALL AMOUNTS WILL BE LIGHT TODAY
HOWEVER WOULD NOT BE SURPRISED IF A FEW LOCATIONS GET AN
ADDITIONAL HALF AN INCH BY TONIGHT.

A RIDGE OF HIGH PRESSURE ALONG WITH WARMER 850 MB READINGS WILL
START TO NOSE INTO OUR CWA TOMORROW AND REMAIN IN CONTROL AT LEAST
INTO TUESDAY. THIS WILL ALLOW FOR DRYING PLUS WARMER READINGS IN
ALL LOCATIONS. TUESDAY IS EXPECTED TO BE THE WARMEST DAY OF THE
WEEK WITH HIGHS IN THE 60S TO LOWER 70S.

AN INSIDE SLIDER WILL DROP DOWN CHRISTMAS EVE (WEDNESDAY) MOSTLY
IMPACTING AREAS TO OUR NORTH AND EAST WITH RAIN ANS SNOW.
HOWEVER...GUIDANCE CONTINUES TO SHOW THE SOUTHERN EXTENT OF THE
MOISTURE MOVING THROUGH OUR AREA ESPECIALLY THE NORTH BAY. THE
BIGGER IMPACT WILL BE TO COOL OFF TEMPERATURES BACK TO NEAR NORMAL
LEVELS. COULD ALSO SEE A FEW INLAND SPOTS DROPPING BACK INTO THE
MID 30S.

LONGER RANGE OUTLOOK GOING INTO 2015 HAS DRIER THAN NORMAL WEATHER
FORECAST. RIGHT NOW TRAVEL CONDITIONS FROM CHRISTMAS TO NEW YEARS
LOOK TO BE GOOD AROUND OUR AREA.

&&

.AVIATION...AS OF 4:15 AM PST SATURDAY...ABUNDANT LOW LEVEL
MOISTURE LEFT OVER FROM THE PAST SYSTEM IS BRINGING LOW CIGS TO
THE SFO BAY AREA. A FEW SHOWERS LINGER FROM THE SOUTH BAY TO THE
MRY BAY AREA. IFR CIGS EXPECTED TO LIFT TO MVFR AFTER 17Z AND VFR
BY 20Z AS THE NEXT APPROACHING SYSTEM PROVIDES SOME MIXING. RAIN
CONFINED TO THE NORTH BAY THIS AFTERNOON AND EVENING. PRESSURES
REMAINING STABLE SO SOUTHEAST WINDS STAYING BELOW 5 KT THROUGH THE
DAY.

VICINITY OF KSFO...IFR CIGS LIFTING TO MVFR AFTER 17-18Z AND VFR
AFTER 20Z. LIGHT SOUTHEAST WINDS 5 KT OR LESS THROUGH THE DAY.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WITH CIGS 4000 FEET
OR ABOVE. ISOLATED LIGHT SHOWERS THROUGH 16Z.

&&

.MARINE...AS OF 4:15 AM PST SATURDAY...LARGE SWELLS HAVE ARRIVED
ALONG THE COAST. AS OF 4 AM...BUOYS REPORT SEAS RANGING FROM 21
FEET AT PT ARENA BUOY TO 13 FEET AT MONTEREY BAY BUOY. SWEL
PERIODS ARE 17-18 SECONDS. EXPECTING SEAS IN THE 17-20 FOOT RANGE
THIS MORNING DECREASING SLOWLY THIS AFTERNOON AND EVENING. HIGH
TIDE AROUND 8:30 AM COULD CAUSE MINOR COASTAL FLOODING NEAR THE
OCEAN. MAIN CONCERN WILL BE DURING KING TIDE SUNDAY MORNING AFTER
9 AM. ALTHOUGH SEAS WILL BE SLIGHTLY LOWER AND SWELL PERIOD WILL
BECOME 14-15 SEONDS...COASTAL FLOODING IS POSSIBLE IN THE SF BAY
AS WELL AS THE OCEAN.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...HIGH SURF ADVISORY AND COASTAL FLOOD
                   ADVISORY...ALL COASTAL LOCATIONS TODAY
             SCA...PT ARENA TO PT REYES 0-10 NM 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 ARENA TO PT REYES 10-60 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...ROUGH BAR ADVISORY FOR SF BAR

&&

$$

PUBLIC FORECAST: BELL
AVIATION/MARINE: W PI

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