Bay Area Forcasts

[Proparoo]

SAN FRANCISCO SAN PABLO SUISUN BAY AND THE WEST DELTA-
300 PM PDT MON MAR 19 2007

...SMALL CRAFT ADVISORY FOR WINDS REMAINS IN EFFECT UNTIL 8 PM
PDT THIS EVENING...

.TONIGHT...W WINDS 15 TO 25 KT WITH GUSTS UP TO 30 KT NORTH OF BAY
BRIDGE...DECREASING TO 5 TO 15 KT. CHANCE OF RAIN.
.TUE...SW WINDS 5 TO 10 KT...BECOMING W 5 TO 15 KT IN THE
AFTERNOON. NUMEROUS SHOWERS.
.TUE NIGHT...W WINDS 15 TO 20 KT...BECOMING NW 5 TO 15 KT AFTER
MIDNIGHT. SCATTERED SHOWERS IN THE EVENING.
.WED...NW WINDS 10 TO 20 KT.
.WED NIGHT...N WINDS 10 TO 20 KT.
.THU...W WINDS 5 TO 15 KT.
.FRI...SW WINDS 10 KT.
.SAT...W WINDS 5 TO 10 KT.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
300 PM PDT MON MAR 19 2007

DISCUSSION...TEMPERATURES DID NOT MAKE IT OUT OF THE 60S IN MOST
PLACES TODAY WITH SOME COASTAL SITES STAYING IN THE UPPER 50S.
A BAND OF LOW CLOUDS IS NOW MOVING ONTO THE COAST AHEAD OF THE
OFFSHORE FRONTAL BAND. SO EXPECT MOST COASTAL AREAS TO SEE
INCREASING LOW TO MID LEVEL CLOUDS THIS AFTERNOON. INLAND AREAS WILL
SEE SOME INCREASING HIGH CLOUDS.

AS NOTED THIS AM THE NAM HAS BEEN ALL OVER THE PLACE WITH QPF
AMOUNTS FOR THIS SYSTEM. THE 18Z RUN NOW TRENDING TOWARDS THE 12Z
GFS. IN FACT THE NAM IS GENERATING RAIN OUT OF THE LOW CLOUDS THAT
BANK UP AGAINST THE COAST THIS EVENING. THIS MAY INDICATE COASTAL
DRIZZLE THIS EVENING ALONG THE SONOMA MARIN SAN FRANCISCO AND SAN
MATEO COASTLINES PRIOR TO THE ACTUAL FRONTAL RAINS DEVELOPING. MAIN
FRONTAL BAND SHOULD BE THROUGH THE NORTH BAY BY SUNRISE AND INTO
THE BAY AREA BY COMMUTE TIME. THUS A MESSY COMMUTE TOMORROW FOR
MOST BAY AREA RESIDENTS. THE FRONT WILL CONTINUE SOUTH WITH RAIN
INTO THE MONTEREY AREA BY MID MORNING AND CONTINUING TO SPREAD
SOUTH THROUGH THE AFTERNOON. LOOKS LIKE THE NAM WANTS TO
GENERATE SOME GOOD SHOWERS TOMORROW AFTERNOON BUT MAINLY SOUTH OF
THE BAY AREA. SO HAVE MENTIONED SHOWERS IN MOST LOCATIONS
THROUGH THE AFTERNOON BUT MOST SHOULD BE IN THE SOUTHERN HALF OF THE
FORECAST AREA. HAVE REMOVED THE THREAT OF THUNDER FOR TOMORROW AS
TE AIR MASS DOES NOT GET VERY UNSTABLE. STRONG SUBSIDENCE MOVING
SOUTH BEHIND THE MAIN UPPER LOW SEEMS TO CLAMP DOWN ON ANY
CONVECTION TRYING TO BUILD.

AFTER TOMORROW EVENING THE THREAT OF RAIN ENDS AND SKIES SHOULD
CLEAR QUICKLY. HIGH PRESSURE BUILDS INTO THE NORTH BOTH AT THE
SURFACE AND ALOFT THAT WILL GENERATE NORTH TO NORTHEAST WINDS IN
THE NORTH AND EAST BAY BY LATE WEDS INTO WEDNESDAY NIGHT. SINCE
THERE WILL BE LITTLE DIRECTIONAL SHEAR FROM THE SURFACE TO ALMOST
20K FT COULD SEE SOME PRETTY GUSTY WINDS IN THE NORTH AND EAST BAY
HILLS WED NIGHT INTO THURSDAY MORNING. ALSO WINDS IN COASTAL GAPS
COULD ALSO BE GUSTY WEDS INTO THUR MORNING. SKIES SHOULD REMAIN CLEAR
AS THE AIRMASS DRIES OUT SIGNIFICANTLY.

EXTENDED...LOOKS LIKE WARM AND DRY WEATHER FOR LATER IN THE
WEEK INTO THE EARLY PART OF THE WEEKEND AS THE LOW PASSING THROUGH
US TONIGHT AND TOMORROW BURIES ITSELF OFF THE COAST OF BAJA ALLOWING
NORTH TO NORTHEAST FLOW OVER OUR AREA TO CONTINUE. BY LATE
SATURDAY THE CUTOFF WILL EJECT EAST AND THE RIDGE OVER US WILL BEGIN
TO COLLAPSE. THIS SHOULD ALLOW ONSHORE FLOW TO INCREASE AND SHOULD
SEE A RETURN TO LOW CLOUDS AND PATCHY FOG FOR SATURDAY NIGHT INTO
SUNDAY MORNING. ALSO COOLER TEMPERTURES MOST AREAS. AS MENTIONED THIS
MORNING MODELS HAVE AND CONTINUE TO BE IN AGREEMENT THAT THE
WESTERLIES AMPLIFY AND SEVERAL DEEP EARLY SPRING COLD UPPER LOWS WILL
MOVE INTO CALIFORNIA BEGINNING LATE SUNDAY NIGHT AND INTO MONDAY AND
TUESDAY AND THEN POSSIBLY ANOTHER ONE LATER IN THE WEEK. HAVE
INTRODUCED RAIN INTO THE FORECAST FOR EARLY NEXT WEEK. FEEL
CONFIDENT THAT THIS IS REAL AND NOT MODEL FANTASY. SEVERAL KEY THINGS
WORKING IN FAVOR OF WET WEATHER RETURNING. FIRST THE TROPICAL
CONVECTIVE FORCING HAS ALREADY STIMULATED THE EAST ASIAN JET TO
EXTEND FURTHER ACROSS THE PACIFIC. THIS WILL ALLOW THE MEAN RIDGE
THAT HAS SEEMED TO TAKE UP PERMANENT RESIDENCE OVER THE WEST COAST TO
MOVE EAST AND THE MAIN TROUGH THAT HAS BEEN OUT NEAR 150W TO MOVE
OVER THE WEST COAST. THE OTHER FEATURE HELPING TO SUPPORT THIS
PATTERN CHANGE IS THE ARCTIC OSCILLATION THAT HAS BEEN POSITIVE
DURING MOST OF THE DRY PERIODS WE HAVE EXPERIENCED THIS WINTER AND IS
FORECAST TO GO NEGATIVE THROUGH THE END OF THE MONTH. THIS HAS BEEN
A CONSISTENT FORECAST BY THE ENSEMBLES FOR SEVERAL DAYS. SO
HOPEFULLY WE CAN RECOVER A LITTLE FROM THIS VERY DRY WINTER AND MAYBE
DELAY FIRE SEASON UP NORTH HERE FOR ANOTHER MONTH.



IWindsurf 3/19/07
http://www.iwindsurf.com/windAndWhere.i ... ast+7+Days

[Bulldog]

If this forecast comes true, then spring 2007 is going to be a repeat of 2005.

[Proparoo]

SAN FRANCISCO SAN PABLO SUISUN BAY AND THE WEST DELTA-
217 AM PDT TUE MAR 20 2007

...SMALL CRAFT ADVISORY FOR WINDS IN EFFECT FROM 2 PM PDT THIS
AFTERNOON THROUGH THIS EVENING...

.TODAY..S WINDS 5 TO 10 KT...BECOMING W AND INCREASING TO 15 TO 25
KT IN THE AFTERNOON. SCATTERED SHOWERS.
.TONIGHT...W WINDS 15 TO 25 KT...BECOMING 5 TO 15 KT AFTER
MIDNIGHT. SCATTERED SHOWERS.
.WED...NW WINDS 5 TO 15 KT.
.WED NIGHT...N WINDS 5 TO 15 KT.
.THU...N WINDS 5 TO 10 KT.
.FRI...N WINDS 5 TO 10 KT.
.SAT...W WINDS 5 TO 15 KT.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
320 AM PDT TUE MAR 20 2007

DISCUSSION...A WEAK FRONTAL SYSTEM IS APPROACHING THE CALIFORNIA
COAST EARLY THIS MORNING. BOTH THE NAM AND GFS HAD FORECAST RAIN TO
BEGIN ACROSS THE NORTH BAY BY NOW...BUT RAIN HAS NOT YET COLLECTED
IN ANY RAIN GAGE ACROSS OUR CWA. SYSTEM IS SPLITTING AS IT
APPROACHES WITH THE NORTHERN PART OF THE SPLIT BRINGING RAIN TO NWRN
CA. THE SOUTHERN PART OF THE SPLIT CAN BE SEEN ON SATELLITE AS A
VORT MAX OUT NEAR 30N/130W. AS THIS VORT MAX APPROACHES THE CENTRAL
CA COAST THIS MORNING...RAINFALL SHOULD BEGIN TO DEVELOP OVER OUR
AREA. STARTING TO SEE MORE WIDESPREAD LIGHT RETURNS ON RADAR
WELL OFFSHORE SO WILL TRUST THE MODELS FOR THE TIME BEING AND KEEP
LIKELY POPS IN THE FORECAST THIS MORNING. THE FRONT IS EXPECTED TO
MOVE THROUGH MOST OF OUR AREA BY MIDDAY AND RAINFALL CHANCES WILL
BEGIN TO DIMINISH IN THE AFTERNOON. ALTHOUGH UNLIKELY...THERE IS A
POSSIBILITY OF THUNDERSTORM DEVELOPMENT CLOSEST TO WHERE THE
VORT MAX COMES ASHORE THIS AFTERNOON. THE 06Z NAM FORECASTS THE MOST
INSTABILITY OVER OUR SOUTHERN COUNTIES THIS AFTERNOON WITH SURFACE
BASED CAPE VALUES AS HIGH AS 650 J/KG. SO WILL FORECAST A SLIGHT
CHANCE OF AFTERNOON THUNDERSTORMS OVER MONTEREY AND SAN BENITO
COUNTIES.

ISOLATED SHOWERS MAY LINGER INTO THE EVENING HOURS...MAINLY ACROSS
THE SOUTH AND EAST. THE UPPER TROUGH IS FORECAST TO DIG SOUTH INTO
SOUTHERN CA OVERNIGHT AND THEN FORM A CUTOFF OVER THE SOUTHERN CA
BITE ON WEDNESDAY. MEANWHILE...AN UPPER RIDGE OVER THE EASTERN
PACIFIC WILL BEGIN TO BUILD OVER NORTHERN CA. THIS WILL SET UP A
DRIER AND WARMER NORTH TO NORTHEAST FLOW OVER OUR AREA FROM LATE
WEDNESDAY INTO THURSDAY. THE BIGGEST UPTURN IN TEMPERATURES ON
WEDNESDAY WILL BE IN THE NORTH BAY WHERE A DEVELOPING NORTHERLY FLOW
WILL PRODUCE THE MOST WARMING AND DRYING. BY THURSDAY A DEEP
OFFSHORE FLOW ALONG WITH A WARMER AIRMASS UNDER A BUILDING RIDGE WILL
ALLOW TEMPS TO WARM ABOVE NORMAL IN ALL AREAS. TEMPERATURES WILL
PROBABLY WARM A FEW MORE DEGREES INLAND ON FRIDAY AS THE RIDGE
STRENGTHENS A BIT MORE...BUT COASTAL AREAS WILL SEE TEMPS HOLD STEADY
OR PERHAPS COOL A FEW DEGREES AS ONSHORE FLOW DEVELOPS BY FRIDAY
AFTERNOON. COOLER AIR WILL BEGIN TO SURGE INLAND ON SATURDAY AS THE
UPPER RIDGE AXIS MOVES TO OUR EAST AND ONSHORE FLOW INCREASES AT ALL
LEVELS. THE GFS INDICATES SOME LIGHT RAIN MAY EVEN MAKE IT`S WAY INTO
THE FAR NORTHERN PART OF OUR FORECAST AREA LATE SATURDAY INTO SUNDAY
AS A STRONG UPPER JET SAGS SOUTH INTO OREGON.

MODELS ARE COMING INTO PRETTY GOOD AGREEMENT EARLY NEXT WEEK. MOST
GFS AND CANADIAN ENSEMBLE MEMBERS...AS WELL AS THE ECMWF...FORECAST A
DEEP UPPER TROUGH OVER CA BY LATE MONDAY. THIS SYSTEM HAS THE
POTENTIAL TO PRODUCE HEAVY RAIN AND/OR STRONG WINDS ACROSS MUCH OF
THE STATE. THIS IS STILL SEVEN DAYS OUT AND WILL WAIT A FEW MORE
MODEL RUNS BEFORE HITTING THIS TOO HARD IN THE FORECAST. BUT
GIVEN THE PRESENT AGREEMENT AMONG THE MODELS...CONFIDENCE IS
RELATIVELY HIGH THAT A SIGNIFICANT STORM WILL IMPACT THE STATE
EARLY NEXT WEEK.