Frost Advisory 4, NWS San Francisco Bay Area, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
219 PM PST SAT JAN 12 2013

.DISCUSSION...AS OF 2:19 PM PST SATURDAY...SATELLITE IMAGERY STILL SHOWS
MOSTLY CLEAR SKIES ACROSS THE DISTRICT. THERE ARE SOME COLD-AIR
CUMULUS CLOUDS THAT HAVE FORMED OVER SOME OF THE COASTAL RANGES.
AFTERNOON TEMPERATURE TRENDS ARE RUNNING COOLER THAN YESTERDAY AT
THIS TIME WITH READINGS STRUGGLING TO EXCEED 50 DEGREES. DEW
POINT TEMPERATURES ARE RUNNING MUCH COOLER WITH READINGS IN THE
20S. TONIGHT IS EXPECTED TO BE COLDER THAN LAST NIGHT...THUS
FREEZE WARNINGS WILL BE POSTED FOR INLAND VALLEY AREAS AND A FROST
ADVISORY WILL BE POSTED FOR THE SAN FRANCISCO BAY SHORELINE AREA
FOR TONIGHT. EARLY INDICATIONS ARE THAT TOMORROW NIGHT WILL
PERHAPS BE COLDER...SO EXTENTIONS OF THE NPW WILL NEED TO BE
CONSIDERED TOMORROW.

HIGH PRESSURE IS FORECAST TO BUILD ALOFT OVER THE EASTERN PACIFIC
AND INTO CALIFORNIA DURING THE COMING WEEK. THIS WILL KEEP ALL
AREAS RAIN FREE THROUGH THE PERIOD. WILL HAVE TO WATCH FOR INTRUSION
OF TULE FOG INTO THE EAST BAY VALLEYS FROM MIDWEEK ON AS OFFSHORE
FLOW SETS UP.

&&

.AVIATION...AS OF 9:43 AM PST SATURDAY...A SURFACE THERMAL TROUGH
WILL DEVELOP OVER CALIFORNIA TODAY...PROVIDING LIGHT WINDS AND
CLEAR SKIES FOR THE TERMINALS. UNDER CLEAR SKIES AFTERNOON
SURFACE TEMPERATURES SHOULD REACH THE LOW TO MID 50S...SLIGHTLY
WARM THAN THE AVERAGE SEA TEMPERATURE. THIS WILL RESULT IN A LIGHT
AFTERNOON SEA BREEZE. THE THERMAL TROUGH WILL STRENGTHEN OVERNIGHT
RESULTING IN LIGHT OSFFHSORE WINDS.

VICINITY OF KSFO...VFR CONDITIONS WILL PREVAIL THROUGH THE
FORECAST PERIOD. THE SEA BREEZE WILL REACH 5 TO 10 KT BETWEEN 2200
AND 0500Z.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR CONDITIONS TODAY AND TONIGHT. WINDS
WILL BE LIGHT WITH THE SEA BREEZE REACHING 5 TO 10 KT BETWEEN 2100
AND 0300Z.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...FROST ADVISORY...CAZ508
             FREEZE WARNING...CAZ506-507-510-513-516-528
             SCA...PT ARENA TO PIGEON PT 10-60 NM FROM 10 PM

&&

PUBLIC FORECAST: SIMS
AVIATION/MARINE: LARRY

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HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
337 AM PST SAT JAN 12 2013

CAZ506>508-510-513-516-528-122345-
NORTH BAY INTERIOR VALLEYS-NORTH BAY MOUNTAINS-
SAN FRANCISCO BAY SHORELINE-EAST BAY INTERIOR VALLEYS-
SANTA CLARA VALLEY...INCLUDING SAN JOSE-
SOUTHERN SALINAS VALLEY...ARROYO SECO...AND LAKE SAN ANTONIO-
NORTHERN SALINAS VALLEY...HOLLISTER VALLEY...AND CARMEL VALLEY-
337 AM PST SAT JAN 12 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE SAN FRANCISCO BAY
SHORELINE AND THE INLAND VALLEYS OF THE GREATER SAN FRANCISCO AND
MONTEREY BAY REGION.

.DAY ONE...SATURDAY AND SATURDAY NIGHT

PARTLY CLOUDY TODAY WITH AFTERNOON HIGHS AROUND 50. A FREEZE WATCH
IS IN EFFECT TONIGHT FOR THE INLAND VALLEYS AND AROUND THE SAN FRANCISCO
BAY SHORELINE LATE TONIGHT THROUGH EARLY SUNDAY MORNING.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

A FREEZE WATCH IS IN EFFECT SUNDAY MORNING. ANOTHER NIGHT OF
FREEZING TEMPERATURES IS EXPECTED SUNDAY NIGHT INTO MONDAY
MORNING. OTHERWISE HIGH PRESSURE WILL BUILD NEXT WEEK WITH A
MODEST WARMING TREND. DENSE TULE FOG WILL BE POSSIBLE IN THE DELTA
AT TIMES.

.SPOTTER INFORMATION STATEMENT...

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