Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

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FXUS66 KMTR 291805
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1105 AM PDT WED JUL 29 2015

...VERY WARM TO HOT INLAND TEMPERATURES EXPECTED THROUGH
THURSDAY...

.SYNOPSIS...HOT TEMPERATURES ARE EXPECTED TO CONTINUE ACROSS THE
INLAND AREAS THROUGH THURSDAY...WITH NEAR NORMAL TEMPERATURES AT
THE COAST AS STRONG HIGH PRESSURE BUILDS OVER THE AREA.
TEMPERATURES WILL COOL SLIGHTLY LATE IN THE WEEK...BUT INCREASING
MONSOON MOISTURE APPROACHING FROM THE SOUTH WILL PROMOTE THE
POSSIBILITY OF SHOWERS AND ISOLATED THUNDERSTORMS BY THE END OF
THE WEEK.

&&

.DISCUSSION...AS OF 10:15 AM PDT WEDNESDAY...A SOUTHERLY SURGE
PUSHED UP THE COAST LAST NIGHT AND ASSOCIATED LOW CLOUDS REMAIN
PRESENT ALONG THE IMMEDIATE COAST AND THE NORTHERN SALINAS VALLEY.
THIS MARINE AIR AND COASTAL LOW CLOUDS WILL RESULT IN NEAR NORMAL
TEMPERATURES FOR COASTAL AREAS TODAY. HOWEVER...THE CURRENT
VISIBLE SATELLITE IMAGE IS SHOWING MOSTLY CLEAR SKIES FOR THE
REMAINDER OF THE CWA. UNDER THESE CLEAR SKIES EXPECT TO SEE HOT
TEMPERATURES AS A STRONG RIDGE OF HIGH PRESSURE RESIDE OVER THE
WEST COAST.

THE CURRENT SATELLITE WATER VAPOUR IMAGE IS SHOWING A RIDGE OF
HIGH PRESSURE ALONG THE WEST COAST WITH A DOME OF HIGH PRESSURE
CENTERED OVER ROUGHLY OKLAHOMA AND A NEW LOW PRESSURE CENTER IS
DEVELOPING AROUND 35 NORTH AND 140 WEST. 1200Z GFS40 AND 0000Z
ECMWF HAVE INITIALIZED WELL WITH THESE SYNOPTIC WEATHER FEATURES
AND REMAIN IN GOOD AGREEMENT THROUGH THE FORECAST PERIOD.

BOTH MODELS MAINTAIN A 591DM RIDGE OF HIGH PRESSURE OVER MUCH OF
THE WEST COAST TODAY AND TOMORROW...PROMOTING HOT TEMPERATURES
AROUND THE FORECAST AREA. BY FRIDAY THE DOME OF HIGH PRESSURE
CURRENTLY CENTERED OVER OKLAHOMA SLIDES WEST AND BEGINS TAPPING
INTO THE MONSOON MOISTURE POOL. THE LOW PRESSURE CENTER CURRENTLY
POSITIONED AT 35 NORTH AND 140 WEST SLIDES CLOSER TO THE COAST BY
FRIDAY AND ENHANCES THE MONSOON MOISTURE PUSH INTO OUR FORECAST
AREA. THE NAM12 AND GFS40 BOTH MOVE SOME VORTICITY ENERGY THROUGH
THE AREA FRIDAY...BUT AT DIFFERENT TIMES. THIS ENERGY WILL PROVIDE
LIFT AND ALONG WITH SOME INSTABILITY WILL PROVIDE SUPPORT FOR
SHOWERS AND THUNDERSTORMS AROUND THE FORECAST AREA BEGINNING
THURSDAY AFTERNOON THROUGH FRIDAY EVENING. INITIALLY THE SHOWER
AND THUNDERSTORM THREAT WILL BEGIN IN MONTEREY AND SAN BENITO
COUNTY BUT WILL SPREAD NORTH FRIDAY INTO NAPA AND SONOMA COUNTIES.

BY THE WEEKEND THE ECMWF AND GFS40 SHOW A LOW PRESSURE SYSTEM
PUSHING INTO BRITISH COLUMBIA...MERGING WITH THE PREVIOUSLY
MENTIONED PACIFIC LOW. THIS FEATURE WILL SUPPRESS THE FOUR
CORNERS HIGH AND RESULT IN SOUTHWEST FLOW WHICH WILL BRING AN END
TO THE SHOWER AND THUNDERSTORM THREAT OVER THE WEEKEND.

&&

.AVIATION...AS OF 10:50 AM PDT WEDNESDAY...LOW CLOUDS HAVE MOSTLY
RETREATED TO THE COAST AT THIS HOUR WITH VFR CONDITIONS AT THE
MAJOR TERMINALS. THE SOUTHERLY SURGE AND DEEPENING MARINE LAYER
WILL LIKELY MAINTAIN CLOUD COVER JUST OFFSHORE THROUGH MUCH OF
THE DAY. EXPECTING A LATE AFTERNOON PUSH INLAND...ESPECIALLY
ACROSS THE MONTEREY BAY AREA THAT WILL PERSIST THROUGH THURSDAY
MORNING.

VICINITY OF KSFO...VFR. LIGHT WINDS WILL STRENGTHEN BY 21Z AND
PERSIST THROUGH THE AFTERNOON HOURS. CONFIDENCE DECREASES THIS
EVENING INTO THURSDAY MORNING WITH RESPECT TO LOW CLOUDS
RETURNING OVER THE TERMINAL. THUS...WILL INTRODUCE SCT CLOUDS
AROUND 12Z THURSDAY MORNING.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR CONDITIONS THROUGH EARLY
AFTERNOON LIKELY AS LOW CLOUDS HAVE RETREATED TO THE COASTLINE.
ONSHORE WINDS INCREASE SLIGHTLY THIS AFTERNOON AND EVENING WITH
LOW CLOUDS LIKELY TO RETURN LATE THIS EVENING.

&&

.CLIMATE...HERE ARE RECORD HIGHS FOR WEDNESDAY AND THURSDAY
WITH THE LAST YEAR THE RECORD WAS RECORDED.

SF BAY AREA.............7/29............7/30
KENTFIELD.............105/1954........105/1977
SAN RAFAEL............101/1977........102/1977
NAPA..................105/1954........103/1977
SAN FRANCISCO..........83/1977.........85/1986
SFO....................91/1977.........97/1977
OAKLAND................98/1977.........95/1977
OAKLAND AIRPORT........91/1977.........95/1977
RICHMOND...............82/1967.........80/1993
LIVERMORE.............108/1954........107/1979
MOUNTAIN VIEW..........93/1977.........97/1977
SAN JOSE...............95/1977........102/1995
GILROY................102/1980........106/1977

MONTEREY BAY AREA.......7/29............7/30
 MONTEREY..............86/1977.........91/1977
 SANTA CRUZ............88/1964........102/1977
 SALINAS...............95/1977.........86/1995
 SALINAS AIRPORT.......92/1977.........84/1977
 KING CITY............105/1977........106/1977

&&

.MARINE...AS OF 08:35 AM PDT WEDNESDAY...GENERALLY LIGHT TO
MODERATE SOUTHERLY WINDS WILL PREVAIL ACROSS THE COASTAL WATERS
FOR THE NEXT FEW DAYS. LOCALLY GUSTY WINDS WILL BE POSSIBLE IN THE
SAN FRANCISCO BAY DURING THE AFTERNOON AND EVENING HOURS. A MIXED
SWELL WILL ALSO CONTINUE TO IMPACT THE COASTAL WATERS THROUGH LATE
WEEK.

&&

.BEACHES...AS OF 06:26 AM PDT WEDNESDAY...BUOYS ALONG THE CENTRAL
COAST AND LOCATIONS TO THE NORTH CONTINUE TO SHOW A SOME WHAT
ENERGETIC SOUTHERLY SWELL. THERE WERE SEVERAL REPORTS OF ROUGH
SURF AND RIP CURRENTS YESTERDAY AT SOUTH FACING BEACHES NEAR SANTA
CRUZ AND STINSON BEACH. GIVEN SIMILAR CONDITIONS TODAY DECIDED TO
ISSUE A BEACH HAZARD FOR RIP CURRENTS VALID THROUGH THIS EVENING.
LARGE SHORE BREAK WILL ALSO BE POSSIBLE.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...SCA...SF BAY FROM NOON

&&

$$

PUBLIC FORECAST: LARRY
AVIATION: RGASS
MARINE: MM/RGASS
CLIMATE: BELL/BENJAMIN


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