Strong Wind in California, January 28, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA CA
248 PM PST THU JAN 28 2010

.DISCUSSION...AS OF 2:30 PM PST THURSDAY...MAIN FOCUS WITH THIS
FORECAST WILL BE RAIN CHANCES FRIDAY WITH UNSETTLED WEATHER PATTERN
NEXT WEEK.

THE MORNING FOG DEFINITELY TOOK TIME TO BURN OFF...BUT IT ACTUALLY
DID BURN OFF TODAY. THIS WAS MOST NOTABLE IN THE SANTA CLARA
VALLEY WHERE TEMPS WERE 5-7 DEGS WARMER TODAY COMPARED TO
YESTERDAY. OTHERWISE...THE NEXT WEATHER SYSTEM CAN ALREADY BE SEEN
ON THE HORIZON.  PER VIS SATELLITE AND OBSERVATIONS HIGH CLOUDS
CONTINUE TO STREAM IN AHEAD OF THE NEXT SYSTEM WHICH IS APPROACHING
130W AS WE SPEAK.

SHORT TERM(TONIGHT-SUNDAY)...
EVEN WITH HIGH CLOUDS STREAMING IN OVERHEAD...BL MOISTURE REMAINS
HIGH. THEREFORE...WILL KEEP PATCHY DENSE FOG WORDING IN AGAIN
TONIGHT FOR INTERIOR VALLEYS. SOMEWHAT SIMILAR TO WAS WAS EXPERIENCED
LAST NIGHT.

SHORT TERM MODELS ARE IN PRETTY GOOD CONSENSUS WITH FRIDAY/S RAIN
CHANCES.  FORECAST MODELS AND HPC ALL PUT THE COLD FRONT OFF THE
NORTH BAY COAST BY 18Z FRIDAY AND DRAG IT S AND E THROUGH 12Z
SATURDAY.  AS A RESULT...PRECIP WILL DEVELOP IN THE N BAY AND
POSS NEAR SF NEAR THE END OF THE MORNING COMMUTE.  THE FRONT DRIFTS
SOUTH THROUGH THE DAY WITH RAINFALL SPREADING SOUTH TOO.  THE UPPER
LEVEL TROUGH ASSOCIATED WITH THE FRONT BECOMES SLIGHTLY NEGATIVE
AND SLOWS DOWN EARLY SATURDAY.  HAVE INCREASE SHOWERS THROUGH MUCH
OF SATURDAY TO ACCOUNT FOR THE UPPER LEVEL SUPPORT. MIDDAY SATURDAY
INTO SATURDAY EVENING THE UPPER LEVEL TROUGH EXITS TO THE EAST
PUTTING AN END TO SHOWER ACTIVITY.  FOG WILL LIKELY DEVELOP AGAIN
SATURDAY NIGHT WITH THE RESIDUAL MOISTURE FROM THE RAINS. SUNDAY
WILL SEE A BREAK IN THE ACTION AS UPPER LEVEL RIDGING BUILDS IN.
OVERALL RAINFALL TOTALS STILL APPEAR TO BE RELATIVELY LIGHT.
GENERALLY SPEAKING A FEW TENTHS TO ONE HALF INCH POSSIBLE IN THE
HILLS AND N BAY...ELSEWHERE A TENTH OR TWO IS EXPECTED.

AS FOR TEMPERATURES...ONE MORE DAY OF 60S IN THE SOUTHERN CWA ON
FRIDAY.  THE PASSING COLD FRONT ON SATURDAY WILL USHER IN COLDER
TEMPERATURES FOR SATURDAY AND SUNDAY.

LONG TERM(MONDAY-THURSDAY)...
MEDIUM RANGE MODELS CONTINUE TO INDICATE AN ACTIVE WEATHER PATTERN
NEXT WEEK AS A SERIES OF STORMS IMPACT THE WEST COAST.  THE WEAKEST
SYSTEM OF THE BUNCH SKIRTS NORTH OF THE BAY AREA MONDAY/TUESDAY WITH
SHOWERS MAINLY NORTH OF SAN JOSE. THE NEXT SYSTEM SLIDES TO THE
COAST WEDNESDAY WITH MORE WIDESPREAD RAINFALL. INTERESTING TO NOTE
WITH THIS SYSTEM IS HOW DIVERSE THE UPPER LEVEL FIELDS WITH THE
MODELS ARE.  THE EURO DRIVES THE H5 LOW WAY SOUTH INTO BAJA AREA
WHILE THE OTHERS KEEP MORE OF A TROUGH OFF THE COAST.  LAST BUT NOT
LEAST...THE STRONGEST STORM APPEARS TO BE NEXT THURSDAY INTO
FRIDAY.  MEDIUM MODELS HAVE BEEN PRETTY CONSISTENT WITH BRINGING
MORE SUBSTANTIAL RAINFALL TO THE GOLDEN STATE.  KEEP IN MIND THAT
IT IS STILL SEVEN DAYS AWAY AND A LOT COULD HAPPEN BETWEEN NOW AND
THEN. FOR NOW WILL INCREASE POPS.

&&

.AVIATION...AS OF 2:48 PM THURSDAY...RIDGE ALOFT PROVIDING LIGHT
PRESSURE GRADIENTS AT THE SURFACE FOR LIGHT WINDS. EXTENSIVE
RESIDUAL LOW-LEVEL MOISTURE RESULTING IN STRATUS AROUND THE S.F.BAY
AREA AS WELL AS RADIATIONAL FOG AND LOW STRATUS FOR COASTAL VALLEYS.
WITH WEAK MID-WINTER SUN...FOG/STRATUS WAS SLOW TO CLEAR. VFR
CONDITIONS THROUGH 05Z THIS EVENING. ONCOMING FRONTAL SYSTEM FOR
FRIDAY EXPECTED TO PROVIDE SOME LIFT AND OVERRUNNING CLOUDINESS TO
SLOW STRATUS/FOG DEVELOPMENT TONIGHT.

VICINITY OF KSFO...VFR CONDITIONS EXPECTED ALL EVENING EXCEPT AT
KSTS WHERE LOW OVERCAST AND DENSE FOG WILL REFORM. WINDS LIGHT AND
VARIABLE THROUGH TONIGHT.

KSFO BRIDGE APPROACH...VFR.

MRY BAY AREA TERMINALS...VFR EXPECTED.

&&

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

PUBLIC FORECAST: MM/RW
AVIATION/MARINE: SSA

NWS ON THE WEB AT WEATHER.GOV/SANFRANCISCO