Small Craft Advisory 194, NWS San Francisco Bay Area, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
156 PM PST TUE DEC 23 2014

.SYNOPSIS...DRY CONDITIONS WILL PERSIST THROUGH EARLY WEDNESDAY
AHEAD OF OUR NEXT WEATHER SYSTEM SET TO IMPACT THE STATE ON
CHRISTMAS EVE...BRINGING LIGHT RAIN TO THE REGION. BREEZY TO GUSTY
WINDS WILL DEVELOP BEHIND THE COLD FRONT WEDNESDAY AFTERNOON AND
EVENING. DRY WEATHER AND COOLER TEMPERATURES RETURN FOR CHRISTMAS
DAY AND WILL LIKELY PERSIST THROUGH THE UPCOMING WEEKEND.

&&

.DISCUSSION...AS OF 01:54 PM PST TUESDAY...HIGH PRESSURE OVER THE
REGION TODAY HAS RESULTED IN CLEAR SKIES AND MILD AFTERNOON
TEMPERATURES...GENERALLY IN THE MID 60S TO LOWER 70S. TEMPERATURES
OVERNIGHT WILL ONLY DROP INTO THE MID 40S TO LOWER 50S (WELL ABOVE
SEASONAL AVERAGES) WITH PATCHY FOG POSSIBLE. MEANWHILE...THE
MID/UPPER LEVEL RIDGE IS FORECAST TO FLATTEN AND BEGIN TO WEAKEN
OVERNIGHT AHEAD OF AN APPROACHING STORM SYSTEM.

THE FORECAST MODELS ARE GENERALLY IN GOOD AGREEMENT WITH A FAST
MOVING MID/UPPER LEVEL TROUGH DIGGING INTO THE PACIFIC NORTHWEST
LATE TONIGHT INTO WEDNESDAY. THIS WILL DRIVE A FRONTAL BOUNDARY INTO
THE NORTH BAY LATE WEDNESDAY MORNING WITH RAIN SPREADING SOUTHWARD
THROUGH THE EARLY AFTERNOON. WHILE THERE IS DECENT MOISTURE
AVAILABLE WITH THIS SYSTEM...IT IS FORECAST TO QUICKLY MOVE THROUGH
THE REGION WEDNESDAY. RAINFALL AMOUNTS ACROSS THE NORTH BAY WILL
GENERALLY BE A FEW TENTHS OF AN INCH WITH UP TO 1/3" IN THE HIGHER
ELEVATIONS. FURTHER SOUTH...ONLY A FEW HUNDREDTHS OF AN INCH OF
RAINFALL IS EXPECTED WITH ISOLATED TOTALS UP TO 1/10" IN THE COASTAL
RANGES. WIND SPEEDS IN WAKE OF THE FRONTAL PASSAGE ARE EXPECTED TO
INCREASE WEDNESDAY AFTERNOON AND EVENING WITH GUSTS TO AROUND 45-50
MPH POSSIBLE IN THE HIGHER ELEVATIONS ACROSS THE REGION. GIVEN THE
SATURATED SOILS FROM EARLIER RAINFALL THIS MONTH...THIS COULD LEAD
TO DOWN TREES AND A FEW POWER OUTAGES.

A MUCH DRIER AND COOLER AIR MASS WILL THEN FILTER IN ACROSS THE
REGION ON CHRISTMAS DAY WITH WIND SPEEDS DIMINISHING AS THE MAIN
MID/UPPER LEVEL SYSTEM PULLS AWAY FROM THE REGION. WITH A RIDGE
BUILDING OFF THE WEST COAST...SKIES WILL CLEAR OUT AND TEMPERATURES
WILL ONLY WARM INTO THE MID 50S FOR MOST LOCATIONS LATE IN THE WEEK.
THE COMBINATION OF GENERALLY CLEAR SKIES AND LIGHT WINDS IN THIS
PATTERN WILL RESULT IN MUCH COOLER OVERNIGHT TEMPERATURES LATE IN
THE WEEK...DROPPING INTO THE 40S NEAR THE COAST AND 30S INLAND.
CANNOT RULE OUT A LIGHT FREEZE IN THE NORTH BAY VALLEYS AND OTHER
SHELTERED INLAND VALLEYS FRIDAY AND SATURDAY MORNINGS.

EXPECTING DRY CONDITIONS TO PERSIST THROUGH THE UPCOMING WEEKEND AND
INTO EARLY NEXT WEEK AS HIGH PRESSURE HOLDS STEADY ACROSS THE
EASTERN PACIFIC. DAYTIME TEMPERATURES WILL REMAIN NEAR SEASONAL
AVERAGES AND OVERNIGHT LOWS WARM SLIGHTLY WITH THE RETURN OF WEAK
ONSHORE FLOW. AT THIS TIME...THE FORECAST MODELS TO NOT APPEAR TO
BRING ANOTHER STORM SYSTEM ACROSS THE REGION THROUGH NEW YEAR'S DAY.
HOWEVER...BE SURE TO CHECK BACK FOR THE LATEST AS THE FORECAST COULD
CHANGE IN THE COMING DAYS.

&&

.AVIATION...AS OF 10:00 AM PST TUESDAY...PREDOMINATELY VFR TODAY
WITH LIGHT WINDS AS HIGH PRESSURE DOMINATE THE REGION. MAY OR MAY
NOT SEE A FEW LOW CLOUDS WITHIN 1000 FT OF THE SURFACE DUE TO A
MOIST SURFACE LAYER... HOWEVER THESE CLOUDS SHOULD NOT BECOME
WIDESPREAD ENOUGH TO IMPACT AIRPORT OPERATIONS. CAN NOT RULE OUT
LOW CEILINGS/VISBYS TOMORROW MORNING IN THE BAY AREA THROUGH
SUNRISE. WINDS PICK UP MIDDAY WEDNESDAY AS A QUICK MOVING TROUGH
DESCENDS THROUGH THE REGION. MODERATE TO STRONG WINDS WILL
INITIATE FROM THE WEST WEDNESDAY AFTERNOON AND INCREASE BEFORE
VEERING TOWARDS THE NORTH.

VICINITY OF KSFO...VFR WITH LIGHT WINDS TODAY. WINDS PICK UP
TOMORROW AFTERNOON WITH WET RUNWAYS POSSIBLE.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR WITH LIGHT WINDS TODAY.

&&

.MARINE...AS OF 09:33 AM PST TUESDAY...DECREASING NORTHWEST WINDS
TODAY AS HIGH PRESSURE SHIFTS ONSHORE. NORTH TO NORTHWEST WINDS
INCREASE IN STRENGTH WEDNESDAY NIGHT AND CHRISTMAS DAY AS A LOW
PRESSURE SYSTEM DROPS INTO THE GREAT BASIN. THERE IS SOME
POTENTIAL FOR OCCASIONAL GALE FORCE WINDS LATE WEDNESDAY INTO
THURSDAY.

&&

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

&&

PUBLIC FORECAST: RGASS
AVIATION/MARINE: DRP

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