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

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866
FXUS66 KMTR 020401
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
901 PM PDT SUN MAY 1 2016

.SYNOPSIS....COASTAL LOW CLOUDS AND FOG WILL CONTINUE TO PUSH
NORTH IMPACTING THE COAST AND INLAND VALLEYS TONIGHT INTO MONDAY
MORNING. DRY AND SEASONABLE WEATHER IS FORECAST THROUGH TUESDAY.
A WEATHER SYSTEM WILL APPROACH CALIFORNIA BY THE MIDDLE OF THE
WEEK...BRINGING A CHANCE OF SHOWERS BEGINNING WEDNESDAY LASTING
INTO THE WEEKEND...ALONG WITH COOLER THAN NORMAL TEMPERATURES.

&&

.DISCUSSION...AS OF 9:01 PM PDT SUNDAY...ACCORDING TO THE
EXPERIMENTAL GOES R IFR PROBABILITY SATELLITE IMAGE LOW CLOUDS AND
FOG ARE WORKING THEIR WAY UP THE BIG SUR AND SANTA CRUZ COAST AT
THIS HOUR. HALF MOON BAY IS ALSO REPORTING REDUCED VISIBILITY AND
LOW CLOUDS. THIS SOUTHERLY SURGE OF LOW CLOUDS AND FOG WILL
CONTINUE NORTHWARD IMPACTING THE COAST AND INLAND VALLEYS
OVERNIGHT INTO MONDAY MORNING. ACCORDING TO THE LATEST RUN OF THE
HRRR FORECAST MODEL...LOW CLOUDS AND FOG SHOULD CLEAR OUT OF THE
INLAND VALLEYS NOT LONG AFTER SUN RISE...BUT WILL REMAIN ALONG THE
COAST THROUGH LATE MORNING.

THE CURRENT SATELLITE WATER VAPOUR IMAGE IS SHOWING A TROUGH OF
LOW PRESSURE CENTERED IN THE GULF OF ALASKA WITH A RIDGE OF HIGH
PRESSURE CENTERED OVER THE SOUTHERN BORDER OF BRITISH COLUMBIA AND
ALBERTA CANADA. THE 0000Z GFS40 AND 1200Z ECMWF HAVE INITIALIZED
WELL WITH THESE FEATURES AND REMAIN IN GOOD AGREEMENT THROUGH AT
LEAST NEXT SATURDAY.

BOTH OF THESE MODELS SLIDE THE PREVIOUSLY MENTIONED TROUGH OF LOW
PRESSURE SOUTH TOWARDS CALIFORNIA...BRINGING THE POTENTIAL FOR
RAIN TO NORTHERN PORTIONS OF THE FORECAST AREA TUESDAY NIGHT
SPREADING SOUTH WEDNESDAY. INSTABILITY ASSOCIATED WITH THE COOL
UPPER LEVEL AIR OF THIS TROUGH OF LOW PRESSURE COULD SUPPORT A FEW
ISOLATED THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING. THE THREAT
OF SHOWERS AND ISOLATED THUNDERSTORMS WILL LINGER THROUGH
THURSDAY. BY FRIDAY THE LOW PRESSURE SYSTEM WILL BE ENTERING
ARIZONA...PLACING THE FORECAST AREA IN A GOOD POSITION FOR WRAP
AROUND SHOWERS INTO THE WEEKEND. THE CURRENT FORECAST PACKAGE DOES
A REASONABLE JOB WITH THE EXPECTED WEATHER CONDITIONS SO NO
UPDATES ARE NEEDED AT THIS TIME.

&&

.AVIATION...AS OF 10:30 AM PDT SUNDAY...DRY OFFSHORE FLOW KEEPING
VFR TODAY. THE ONE FLY IN THE OINTMENT IN THE FORECAST IS A
POSSIBLE SOUTHERLY SURGE LATER TODAY. LATEST NAM AND WRF SHOW A
SOUTHERLY SURGE IMPACTING KMRY/KSNS...POSS MAKING IT INTO SF BAY
OVERNIGHT. CONF IS MARGINAL.

VICINITY OF KSFO...VFR.

SFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY TERMINALS...VFR BECOMING MVFR LATE THIS EVENING AND
OVERNIGHT.

&&

.MARINE...AS OF 01:22 PM PDT SUNDAY...HIGH PRESSURE OVER THE
EASTERN PACIFIC WILL KEEP NORTHERLY WINDS OVER THE COASTAL WATERS
TODAY. LOCALLY GUSTY WINDS WILL BE POSSIBLE OVER THE OUTER WATERS
NORTH OF POINT REYES. SOUTHERLY WINDS WILL DEVELOP LATE TONIGHT
AND EARLY MONDAY. A MODERATE SWELL WILL MIX WITH A SMALLER LONG
PERIOD SOUTHERLY SWELL THIS WEEK.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...NONE.

$$

PUBLIC FORECAST: LARRY
AVIATION: SIMS
MARINE: SIMS


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