FXUS66 KMTR 110556
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
956 PM PST FRI FEB 10 2012

.DISCUSSION...A WEAK DISTURBANCE THAT MOVED ACROSS THE REGION
TODAY BROUGHT LIGHT RAIN OR DRIZZLE TO THE DISTRICT. MANY 
LOCATIONS REPORTED ANYWHERE FROM A HUNDREDTH TO A TENTH OF AN INCH
OF PRECIPITATION ACROSS THE FORECAST AREA. A COUPLE LOCATIONS SUCH
AS VENADO AND MOUNT SAINT HELENA REPORTED OVER TWO TENTHS OF AN
INCH WHILE WOODACRE REPORTED JUST UNDER TWO TENTHS. IT WAS NOT A
SOAKER BY ANY MEANS BUT CAUGHT MANY OFF GUARD WITH ITS HIT OR MISS
NATURE.

CURRENT SATELLITE IMAGERY SHOWS A LINE OF LIGHT RAIN SHOWERS 
TRAVERSING THE BAY AREA THIS EVENING WITH VERY LIGHT 
ACCUMULATIONS BEING REPORTED. SHOWERS ARE ANTICIPATED TO DISSIPATE
OVERNIGHT...HOWEVER A STRAY SHOWER CANNOT BE RULED OUT THROUGH
SATURDAY MORNING AS THE SYSTEM GRADUALLY MOVES EAST.

DRY WEATHER AND A COOL NORTHERLY FLOW WILL SET UP OVER THE REGION
SATURDAY AS THE UPPER LEVEL TROUGH SHIFTS TO THE EAST. THIS WILL
CAUSE TEMPERATURE TO DIP INTO THE 50S AND LOW 60S SATURDAY AND
INTO THE MID 30S AND 40S SATURDAY NIGHT. TEMPERATURES WILL WARM
EVER SO SLIGHTLY ON SUNDAY AS A WEAK RIDGE DEVELOPS OVER THE
DISTRICT BUT ANY EFFECTS FROM THIS WILL BE SHORT LIVED AS THE NEXT
SYSTEM SLIDES INTO THE AREA FROM THE NORTH BRINGING ANOTHER ROUND
OF RAIN SHOWERS TO THE CWA.

FROM PREVIOUS DISCUSSION...
A STRONGER SHORTWAVE WILL MOVE SOUTHEAST INTO THE PACIFIC
NW/NORTHERN CALIFORNIA SUNDAY NIGHT INTO MONDAY. LIGHT RAIN WILL
OVERSPREAD THE DISTRICT SUNDAY NIGHT WITH LIKELY POPS NORTH OF SAN
JOSE. THIS WILL BE MORE OF A HIGH POP LOW QPF SYSTEM. THERE WILL
BE A CHANCE OF SHOWERS ON MONDAY IN THE MOIST NW FLOW. TEMPS WILL
REMAIN COOL. SHOWERS COULD LINGER IN PORTIONS OF THE DISTRICT
MONDAY EVENING AS WELL.

MODELS DO DIVERGE AFTER MONDAY WITH THE GFS BRINGING A CLOSED LOW
ALONG THE COAST ON TUESDAY. HOWEVER...THE ECMWF HAS BEEN
CONSISTENT IN DEVELOPING A WEAK RIDGE ALONG THE CA COAST
TUESDAY...SO HAVE FOLLOWED THE ECMWF SOLUTION. AN UPPER LOW WILL
MOVE ONSHORE INTO THE PACIFIC NORTHWEST WEDNESDAY...THEN DROP
SOUTHEAST INTO NEVADA ON THURSDAY. THIS TRACK SHOULD KEEP ANY
SHOWER ACTIVITY TO THE NORTH AND EAST OF THE DISTRICT SO HAVE DRY
WEATHER THROUGH THE END OF THE UPCOMING WEEK WITH MILD TEMPS.

&&

.AVIATION...AS OF 9:55 PM PST FRIDAY...A WEAK UPPER TROUGH MOVING
ONSHORE CONTINUES TO PRODUCE LIGHT ONSHORE FLOW AND CONSIDERABLE
CLOUD COVER. CIGS ARE CURRENTLY MVFR OR ABOVE...BUT EXPECT MORE
WIDESPREAD MVFR CIGS TO DEVELOP OVERNIGHT AS BOUNDARY LAYER COOLS.
A WEAK FRONTAL BOUNDARY PRODUCED BRIEF LIGHT RAIN EARLIER ON
FRIDAY EVENING...BUT THAT SHOULD BE THE LAST OF THE RAINFALL.
DRIER NORTHWEST FLOW ALOFT WILL BEGIN TO DEVELOP LATE TONIGHT AND
THEN CONTINUE INTO SATURDAY MORNING. NORTHWEST FLOW WILL MIX DRIER
AIR INTO THE LOW LEVELS AND RESULT IN GRADUALLY IMPROVING
CONDITIONS FROM ABOUT SUNRISE THROUGH MIDDAY SATURDAY. VFR
CONDITIONS ARE THEN EXPECTED FROM LATE SATURDAY MORNING THROUGH
SATURDAY EVENING. LIGHT WINDS OVERNIGHT WILL BECOME MODERATE FROM
THE WEST AND NORTHWEST BY SATURDAY AFTERNOON.

VICINITY OF KSFO...MVFR CIGS WILL LIKELY DEVELOP BY 10Z AND THEN
CONTINUE UNTIL ABOUT 18Z SATURDAY. VFR CONDITIONS ARE FORECAST
AFTER 18Z. WINDS WILL BE LIGHT WESTERLY THROUGH SATURDAY
MORNING...AND THEN BECOME MODERATE FROM THE WEST ON SATURDAY
AFTERNOON.

KSFO BRIDGE APPROACH....SIMILAR TO SFO.

MONTEREY BAY AREA TERMINALS...MVFR CIGS EXPECTED THROUGH SATURDAY
MORNING WITH VFR CONDITIONS THEREAFTER. LIGHT WINDS WILL INCREASE
SLIGHTLY FROM THE WEST ON SATURDAY AFTERNOON.

&&

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

&&

$$

PUBLIC FORECAST: CW
AVIATION/MARINE: DYKEMA