Since July 1, we have had 0.00 " of rain. Average seasonal rainfall for July 2nd is 0".

CAZ506-510-513-031300- NORTH BAY INTERIOR VALLEYS-EAST BAY INTERIOR VALLEYS- SANTA CLARA VALLEY...INCLUDING SAN JOSE- 400 PM PDT THU JUL 2 2009

TONIGHT: CLEAR IN THE EVENING THEN PATCHY LOW CLOUDS AND FOG. LOWS IN THE MID TO UPPER 50S. SOUTHWEST WINDS 5 TO 15 MPH.

FRIDAY: PATCHY LOW CLOUDS AND FOG IN THE MORNING THEN SUNNY. HIGHS IN THE 80S TO LOWER 90S. SOUTHWEST WINDS 5 TO 15 MPH.

FRIDAY NIGHT: CLEAR IN THE EVENING THEN PATCHY LOW CLOUDS AND FOG. LOWS IN THE MID 50S. WEST WINDS 10 TO 20 MPH...BECOMING 5 TO 10 MPH AFTER MIDNIGHT.

INDEPENDENCE DAY: MOSTLY CLOUDY IN THE MORNING THEN BECOMING MOSTLY SUNNY. PATCHY FOG IN THE MORNING. HIGHS IN THE 80S TO LOWER 90S. WEST WINDS 5 TO 15 MPH.

SATURDAY NIGHT: MOSTLY CLEAR IN THE EVENING THEN BECOMING MOSTLY CLOUDY. PATCHY FOG AFTER MIDNIGHT. LOWS IN THE MID 50S. WEST WINDS 10 TO 20 MPH...BECOMING SOUTHWEST 5 TO 10 MPH AFTER MIDNIGHT.

SUNDAY: PATCHY LOW CLOUDS AND FOG IN THE MORNING THEN MOSTLY SUNNY. HIGHS IN THE MID 70S TO UPPER 80S.

SUNDAY NIGHT AND MONDAY: PARTLY CLOUDY WITH PATCHY FOG. LOWS IN THE MID 50S. HIGHS IN THE 70S TO 80S.

MONDAY NIGHT THROUGH THURSDAY: MOSTLY CLEAR. LOWS IN THE 50S. HIGHS IN THE LOWER 70S TO MID 80S. && TEMPERATURE / PRECIPITATION SANTA ROSA 54 83 54 85 / 0 0 10 0 SAN RAFAEL 55 80 54 81 / 0 0 10 0 NAPA 55 84 54 84 / 0 0 10 0 SAN JOSE 59 87 58 84 / 0 10 10 0 MORGAN HILL 58 90 57 90 / 0 0 10 0 CONCORD 56 90 58 90 / 0 0 10 0 LIVERMORE 56 93 57 91 / 0 10 10 0

FXUS66 KMTR 022344 AFDMTR

AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA CA 223 PM PDT THU JUL 2 2009

DISCUSSION: AS OF 2:23 PM PDT THURSDAY...MOSTLY CLEAR SKIES ARE EVIDENT ON THE LATEST VISIBLE SATELLITE IMAGE ACROSS THE CWA THIS AFTERNOON. THERE ARE HOWEVER NUMEROUS THUNDERSTORMS OCCURRING ALONG THE SIERRA. AFTERNOON TEMPERATURES ARE RUNNING RIGHT AROUND NORMAL WITH THE COAST SEEING MID 60S TO LOW 70S AND AREAS INLAND IN THE MID 70S TO MID 80S.

ACCORDING TO THE FORT ORD PROFILER THE MARINE LAYER IS AT ABOUT 1400 FEET DEEP THIS AFTERNOON. MEANWHILE THE ONSHORE PRESSURE GRADIENT IS AROUND 2 MB. THESE TWO FACTORS SUPPORT THE RECURRENCE OF STRATUS OVERNIGHT WITH SOME PATCHY DENSE FOG. STRATUS SHOULD STRETCH INTO THE EAST BAY AREA AND INTO THE SOUTHERN SALINAS VALLEY BY EARLY MORNING.

AS FOR THE HOLIDAY WEEKEND BOTH THE 1200 UTC OPERATIONAL GFS AND ECMWF ADVERTISE A LOW APPROACHING THE PACIFIC NORTHWEST. PRECIPITATION ASSOCIATED WITH THIS LOW WILL STAY WELL TO THE NORTH OF THE FORECAST AREA. THE AIRMASS APPEARS TO BE FAIRLY DRY THEREFORE NOT EXPECTING ANY CONVECTION OVER THE CWA BUT MAY SEE SOME CUMULUS OVER THE NORTHBAY AND EAST-BAY HILLS. AGAIN THIS WEEKEND APPEARS TO BE TYPICAL FOR A CENTRAL COAST SUMMER WITH MORNING LOW CLOUDS AND AFTERNOON SUN. TEMPERATURES WILL BE NEAR NORMAL THIS WEEKEND WITH AFTERNOON HIGHS IN THE MID TO UPPER 60S ALONG THE COAST AND MID TO UPPER 80S INLAND WITH SOME LOW 90S POSSIBLE IN THE SOUTHERN SALINAS VALLEY.

THE UPCOMING WORK WEEK WILL BE COOLER WITH AFTERNOON TEMPERATURES INLAND ONLY REACHING THE LOW TO MID 70S AND MID TO UPPER 60S ALONG THE COAST. THIS IS DUE TO AN UNSEASONABLY DEEP TROUGH...WELL ADVERTISED BY BOTH THE ECMWF AND GFS...SLOWLY PASSING OVER THE WEST COAST. 500MB HEIGHTS WILL DROP TO 573 DM OVER THE BAY AREA TUESDAY BRINGING 850 TEMPERATURES TO 13 DEGREES CELSIUS. FURTHER COOLING IS EXPECTED BY WEDNESDAY WITH THE GFS SHOWING 850 TEMPERATURES OF 12 DEGREES CELSIUS FOR THE BAY AREA.

AT THE MOMENT THIS TROUGH APPEARS TO BE DRY FOR THE AREA. HOWEVER... THE GFS INDICATES A SIGNIFICANT VORTMAX PASSING OVER NORTHERN CALIFORNIA WEDNESDAY AFTERNOON ACCOMPANIED BY A 110 KT JET MAX. IF SOME MOISTURE WORKS ITS WAY INTO THE SYSTEM WE COULD SEE A FEW ELEVATED THUNDERSTORMS AS A RESULT. THIS EVENT IS STILL A WAYS OFF AND WITH ONLY MARGINAL MID LEVEL MOISTURE PRESENT IN THE MODEL SOLUTIONS WE HAVE NOT INTRODUCED THUNDERSTORMS INTO THE FORECAST FOR THE NORTHBAY AREA. THIS SITUATION WILL BE MONITORED AS WE GET CLOSER TO NEXT WEEK.

&&

AVIATION: AS OF 4:30 PM PDT THURSDAY...STRATUS HAS RETREATED AWAY FROM THE IMMEDIATE COAST. SOUTHWESTERLY FLOW WILL BRING LOW CEILINGS BACK ONSHORE LATER TONIGHT.

VICINITY OF KSFO...SOUTHWESTERLY FLOW WILL KEEP VFR CONDITIONS THROUGH THE AIRPORT EVENING RUSH HOUR. LOW CEILINGS WILL SPREAD OVER THE AIRPORT AFTER MIDNIGHT AND STAY THROUGH 17-18Z WITH BASES AROUND 1000-1200 FEET.

KSFO BRIDGE APPROACH...STRATUS WILL STAY OUT UNTIL AT LEAST 08Z. BASES EXPECTED TO BE AROUND 1000-1200 FEET. CLEARING BY 18Z.

MONTEREY BAY TERMINALS...STRATUS WILL RETURN BY 04Z WITH CEILINGS STARTING OUT AT 1000-1500 FEET BEFORE LOWERING TO 500-1000 FEET A COUPLE OF HOURS LATER. CLEARING BY 18Z.

&&

MTR WATCHES/WARNINGS/ADVISORIES...

TNGT: SCA...SF BAY.

&&

PUBLIC FORECAST: LARRY AVIATION/MARINE: W PI

NWS ON THE WEB AT WEATHER.GOV/SANFRANCISCO