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

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000
FXUS66 KMTR 030028
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
528 PM PDT SUN AUG 2 2015

.SYNOPSIS...A SUBTLE COOLING TREND IS FORECAST TO CONTINUE THROUGH
TUESDAY AS ONSHORE FLOW AND THE MARINE INFLUENCE INCREASES. MODEST
WARMING IS THEN FORECAST FOR WEDNESDAY AND THURSDAY. ASIDE FROM
PATCHY COASTAL DRIZZLE AND FOG DURING THE OVERNIGHT AND EARLY
MORNING HOURS...DRY WEATHER CONDITIONS ARE EXPECTED TO PERSIST
THROUGH THE FORECAST PERIOD.

&&

.DISCUSSION...AS OF 01:30 PM PDT SUNDAY...AFTER A CLOUDY START TO
THE TODAY...MUCH OF THE BAY AREA CLEAR OUT...EVEN SOME COASTAL
LOCATIONS. DESPITE THE CLEARING TEMPERATURES TODAY ARE RUNNING A
FEW COOLER THAN YESTERDAY. THIS IS MOST LIKELY DUE TO THE FILTERED
SUNSHINE FROM HIGH CLOUDS OVERHEAD AND SLIGHTLY COOLER AIRMASS.

THE LONG WAVE PATTERN CONTINUES TO SHOW AN UPPER LEVEL RIDGE
COVERING MUCH OF THE WEST. HOWEVER...A CLOSED UPPER LOW AND BROAD
TROUGH REMAIN PARKED WEST OF 130W. THE CIRCULATION ASSOCIATED WITH
THE TROUGH/LOW IS HELPING TO STREAM THE UPPER LEVEL CLOUDS OVER
THE BAY AREA. LATEST GUIDANCE SHOWS THE RIDGE WEAKENING WITH THE
LOW REMAINING NEARLY STATIONARY THROUGH MID WEEK. THEREFORE...DAY
TO DAY CHANGE OF SENSIBLE WEATHER WILL BE SMALL. NIGHT AND MORNING
CLOUDS WILL BE COMMON WITH AFTERNOON SUNSHINE. TEMPERATURES WILL
REMAIN SEASONABLY COOL WITH HIGHS IN THE 60S/70S COAST AND 80S/LOW
-MID 90S INLAND.

TEMPERATURES WILL WARM UP BRIEFLY FOR WEDNESDAY AND THURSDAY AS
SHORTWAVE RIDGING DEVELOPS OVER THE REGION THANKS TO A DEEPENING
UPPER LOW TO THE WEST. COASTAL CLOUDS WILL KEEP TEMPERATURES IN
CHECK...BUT INLAND AREAS WILL BE MORE SEASONABLE WITH MORE
LOCATIONS IN THE 90S.

TEMPERATURES MODERATE ON THURSDAY BUT COOL DOWN FRIDAY AND OVER
THE WEEKEND. ANOTHER UPPER LOW IS FORECAST TO DEVELOP OFF THE
COAST LATE IN THE WEEK AND GRADUALLY MOVE INLAND...THE REASON FOR
THE COOL DOWN. IN ADDITION...SOME OF THE MODEL GUIDANCE SUGGESTS
POSSIBLE PRECIPITATION FOR PORTIONS OF CA. MOISTURE AND
INSTABILITY LOOK MARGINAL AT THIS POINT FOR THE BAY AREA. BETTER
CHANCE NORTH OF THE CWA. GIVEN THAT TIME PERIOD IS STILL SEVERAL
DAYS AWAY AND GUIDANCE IS NOT THE BEST...WILL NOT INCLUDE ANY
MENTION OF PRECIP. HOWEVER...A BIG HOWEVER...WILL HAVE TO WATCH
THIS CLOSELY GIVEN RECENT FIRE WEATHER CONCERNS AROUND THE STATE.
ESPECIALLY FROM A POSSIBLE CONVECTION STANDPOINT IMPACTING CURRENT
FIRE FIGHTING EFFORTS.

&&

.AVIATION...AS OF 5:21 PM PDT SUNDAY...A CLOSED UPPER LEVEL LOW
REMAINS LOCATED 600 MILES WEST OF CAPE MENDOCINO. MUCH DRIER AND
SOMEWHAT COOLER AIR IN THE LOWER TO MID LEVELS WELL EAST OF THE
LOW CENTER HAS HELPED ERODE THE COASTAL STRATUS CLOUDS TODAY.
MAINLY WESTERLY WINDS WILL CONTINUE AT THE SURFACE WHILE SW WINDS
CONTINUE ALOFT. STRATUS WILL REDEVELOP TONIGHT...BUT WILL BE
SLOWER THAN LAST EVENING`S REDEVELOPMENT AS MODEST LEVELS OF
MIXING CONTINUE AT THE INTERFACE BETWEEN THE TOP OF THE MARINE
LAYER INVERSION AND THE LOWER LEVEL COOLER/DRIER AIR.

VICINITY OF KSFO...VFR. WESTERLY WIND GUSTS TO 20-22 KNOTS
FORECAST TIL 04Z. COORD WITH CWSU OAKLAND AND AGREE STRATUS LIKELY
TO REDEVELOP BUT NOT UNTIL VERY LATE...00Z KSFO TAF ADVERTISES TEMPO
MVFR CIG 09Z-13Z FOLLOWED BY PREVAILING MVFR TIL 18Z MONDAY.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR FOR MOST OF THE EVENING FOLLOWED
BY TEMPO IFR CIGS 06Z-10Z. IFR CIGS LATE TONIGHT. CLEARING RETURNS
BY LATE MONDAY MORNING.

&&

.MARINE...AS OF 01:22 PM PDT SUNDAY...WEAK LOW PRESSURE OFF THE
SOUTHERN CALIFORNIA COAST WILL GENERALLY RESULT IN LIGHT WINDS
ACROSS THE COASTAL WATERS THROUGH TUESDAY. HOWEVER...LOCALLY
STRONGER WINDS WILL EXIST THIS AFTERNOON AND EVENING OFF OF THE
BIG SUR COAST. BY MIDWEEK...HIGH PRESSURE WILL START TO BUILD OFF
THE NORTHERN CALIFORNIA COAST BRINGING INCREASING NORTHWEST WINDS.
SEAS WILL BE MIXED...NORTHWEST SWELL AND LONG PERIOD SOUTH TO
SOUTHWEST SWELL INTO NEXT WEEK.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM UNTIL 9 PM

&&

$$

PUBLIC FORECAST: MM
AVIATION: CANEPA
MARINE: RGASS


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