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

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000
FXUS66 KMTR 261138
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
438 AM PDT SAT JUL 26 2014

.SYNOPSIS...A RIDGE OF HIGH PRESSURE WILL REMAIN IN PLACE ABOVE
THE SURFACE WHICH WILL KEEP DRY AND SEASONABLE CONDITIONS FOR THE
NEXT SEVERAL DAYS. TEMPERATURES WILL COOL TODAY AND SUNDAY WITH A
STRONGER SEA BREEZE EXPECTED BUT IT WILL REMAIN HOT ACROSS
INTERIOR AREAS BUT COOLER ON THE COAST. A QUIET WEATHER PATTERN
SHOULD CONTINUE WITH DRY WEATHER AND WARM TEMPERATURES.

&&

.DISCUSSION...AS OF 02:38 AM PDT SATURDAY...
FORECAST FOCUS WILL BE ON AMOUNT OF COOLING FOR HIGH TEMPERATURES
TODAY AND SUNDAY...AS WELL AS NORTHWARD EXTENT OF DEEPER MOISTURE
CURRENTLY IN EXTREME SOUTHERN CALIFORNIA.

FOR TODAY...MID LEVEL PATTERN CONTINUES TO SHOW A STRONG RIDGE OF
HIGH PRESSURE NEAR THE FOUR CORNERS REGION AND A WEAK LOW
CURRENTLY CENTERED AROUND 130W. THERE WILL BE LITTLE CHANGE IN
HEIGHTS OR 850 MB TEMPS TODAY AS IT APPEARS THE COOLING WILL BE
DUE TO CHANGES IN SURFACE FEATURES THAT WILL FACILITATE A STRONGER
SEA BREEZE TODAY. NOTING THAT WHILE TEMPERATURES NOW ARE CURRENTLY
NEAR OR WARMER THAN THIS TIME YESTERDAY...SEA LEVEL PRESSURE IS
FORECAST TO RISE THROUGH THE DAY AS THE THERMAL TROUGH SLIDES
EAST. SO WILL SEE A FAIRLY STRONG COOL DOWN FOR COASTAL AREAS AND
MOST OF THE MAJOR URBAN BAY AREA LOCALES ON THE ORDER OF 5 TO 10
DEGREES. IT WILL BE COOLER IN THE HOT SPOTS OF THE FAR INTERIOR
VALLEYS AS WELL BUT ONLY BY A FEW DEGREES. TEMPERATURES WILL STILL
EXCEED 100 DEGREES TODAY FOR EAST AND NORTH BAY HOT SPOTS AND
SOUTHERN SAN BENITO AND MONTEREY COUNTY.

THE SECOND LIMITING FACTOR TODAY IS GOING TO BE THE PRESENCE OF
INCREASED MID LEVEL MOISTURE IN THE AREA WHICH ALREADY SHOWS UP ON
INFRARED SATELLITE WITH CLOUDS PRESENT IN THE SOUTHERN THIRD OF
THE FORECAST AREA. PWAT SHOWS A PLUME OF HIGH MOISTURE IN SOUTHERN
CALIFORNIA WITH A NORTHWARD EXTENSION THAT SHOULD PRESS UP INTO
AREAS FROM MONTEREY BAY SOUTH WITH VALUES IN EXCESS OF 1 INCH OVER
THE WEEKEND. SOME MINOR EVIDENCE OF WEAK ELEVATED INSTABILITY AS
EVIDENCED BY MARGINALLY FAVORABLE MODIFIED TT VALUES IN THE
SOUTHERN AREAS OVERLAPPED WITH HIGHER MID LEVEL MOISTURE. WILL
MONITOR THIS BUT NOT IMPRESSED ENOUGH TO ADD MENTION OF CONVECTION
TODAY BUT ACKNOWLEDGING THAT IT IS A NONZERO CHANCE.

TEMPERATURES WILL REMAIN STEADY THROUGH THE REST OF THE PERIOD AS
THERE IS LITTLE CHANGE IN THE OVERALL PATTERN WITH A RIDGE OF HIGH
PRESSURE IN PLACE. HOWEVER BY NEXT WEEKEND THERE IS THE APPROACH
OF A TROUGH FROM THE NORTHWEST AND THIS MAY INTRODUCE SOME WARMING
TEMPERATURES AHEAD OF IT.

&&

.AVIATION...AS OF 04:30 AM PDT FRIDAY...THE NORTHERLY GRADIENT HAS
WEAKENED BUT REMAINS MODERATE AT OVER 4 MB ACV SFO AND MARINE
LAYER IS AROUND 1000 FEET KEEPING STRATUS AT BAY EXCEPT NEAR COAST
FROM HALF MOON BAY SOUTH. BRIEF LOW CLOUDS POSSIBLE AT OAK NEAR
SUNRISE...OTHERWISE VFR BAY AREA AND IFR MRY BAY THROUGH MID TO
LATE MORNING. MODERATE SEABREEZE THIS AFTERNOON. STRATUS RETURNING TO
MRY BAY TONIGHT.

VICINITY OF KSFO...VFR. WEST WINDS ALL DAY...INCREASING TO AROUND
17 KT THIS AFTERNOON.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...IFR CIGS THIS MORNING. BURN OFF
LIKELY BY MID MORNING HOWEVER SOME GUIDANCE INDICATING CLOSER TO
NOON...CONFIDENCE LOW. STRATUS TO RETURN BY EVENING.

&&

.MARINE...AS OF 02:38 AM PDT SATURDAY...NORTHWEST WINDS OVER THE
NORTHERN COASTAL WATERS ARE CONTINUING TO DIMINISH THIS MORNING.
LIGHT WINDS AND SEAS WILL CONTINUE THROUGH THE WEEKEND INTO EARLY
NEXT WEEK.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...SCA...PT ARENA TO PT REYES 10-60 NM
             SCA...PT REYES TO PIGEON PT 10-60 NM UNTIL 9 AM
             SCA...SF BAY NORTH OF THE BAY BRIDGE FROM 3 PM

&&

$$

PUBLIC FORECAST: JOHNSON
AVIATION/MARINE: AC

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