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

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000
FXUS66 KMTR 282052
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
152 PM PDT THU MAY 28 2015

.SYNOPSIS...A MODEST WARMING TREND REMAINS ON TRACK THROUGH
SATURDAY AS A RIDGE OF HIGH PRESSURE CONTINUES TO BUILD ALONG THE
WEST COAST. THIS WARMING TREND WILL BE MOST APPARENT INLAND.
COOLER TEMPERATURES ARE EXPECTED BEGINNING SUNDAY AS A LOW
PRESSURE SYSTEM APPROACHES THE COAST. THERE IS A SLIGHT CHANCE OF
SHOWERS ACROSS THE NORTH BAY FROM LATE SUNDAY INTO MONDAY WITH
NIGHT TIME COASTAL DRIZZLE EXPECTED.

&&

.DISCUSSION...AS OF 1:52 PM PDT THURSDAY...LOW CLOUDS HAVE CLEARED
FROM THE INLAND AREAS. HOWEVER...COASTAL LOW CLOUDS ARE STILL
APPARENT ON THE CURRENT VISIBLE SATELLITE IMAGE. THE FORT ORD
PROFILER IS SHOWING THE MARINE LAYER SLOWLY COMPRESSING BENEATH
THE BUILDING RIDGE OF HIGH PRESSURE. WITH THE COMPRESSING MARINE
LAYER LOW CLOUDS SHOULD BE LESS WIDE SPREAD TONIGHT BUT WILL STILL
FILL INTO THE INLAND VALLEYS AS WELL AS SAN FRANCISCO AND MONTEREY
BAYS. CLEARING SHOULD TAKE PLACE A LITTLE EARLIER FRIDAY MORNING
THAN IT OCCURRED THIS MORNING.

CURRENTLY THE SATELLITE WATER VAPOUR IMAGE IS SHOWING A SLOW
MOVING LOW PRESSURE SYSTEM CENTERED AROUND 40N 150W WHILE A RIDGE
OF HIGH PRESSURE CONTINUES TO BUILD ALONG THE CENTRAL AND SOUTHERN
CALIFORNIA COAST.

THE 1200Z ECMWF AND GFS40 HAVE INITIALIZED WELL WITH THE CURRENT
SYNOPTIC PATTERN AND MAINTAIN A WEAK RIDGE OF HIGH PRESSURE OVER
THE AREA THROUGH AT LEAST SATURDAY. AS A RESULT OF THIS RIDGE OF
HIGH PRESSURE EXPECT TEMPERATURES TO BE CLOSER TO NORMAL SEASONAL
VALUES THROUGH SATURDAY.

BOTH MODELS CONTINUE TO DRIVE THE PREVIOUSLY MENTIONED LOW PRESSURE
SYSTEM TOWARDS THE COAST OVER THE NEXT FEW DAYS. THE LOW WILL
BEGIN TO IMPACT THE AREA SUNDAY WITH COOLER TEMPERATURES AND
NIGHT TIME COASTAL DRIZZLE. A SLIGHT CHANCE OF SHOWERS OVER THE
NORTH BAY WILL ALSO BE POSSIBLE SUNDAY EVENING INTO MONDAY
MORNING. THE LOW WILL QUICKLY PASS TO THE NORTHEAST MONDAY WITH
QUAZI-ZONAL FLOW FILLING IN BEHIND. THIS QUAZI-ZONAL FLOW WILL
MAINTAIN MILD TEMPERATURES THROUGH THE UPCOMING WORK WEEK.

&&

.AVIATION...AS OF 10:50 AM PDT THURSDAY...A COMPRESSED MARINE
LAYER AROUND 2KFT DEEP HAS RESULTED IN LOW CIGS ACROSS THE REGION
WITH BURN-OFF OCCURRING INLAND. MEANWHILE...A WEAK SHORT- WAVE AND
ASSOCIATED MID/HIGH LEVEL CLOUDS MOVING OVERHEAD APPEARS TO HAVE
SLOWED THE BURN-OFF OVER THE SAN FRANCISCO BAY AREA. SHOULD SEE
CIGS LIFT AND BEGIN TO SCATTER OUT BY 20Z OVER THIS REGION ALONG
WITH AN INCREASE IN ONSHORE FLOW. FURTHER SOUTH...LOW CIGS HAVE
SCATTERED OUT...YET MAY BRIEFLY RETURN OVER THE MONTEREY TERMINAL.
EXPECTING A RETURN OF MVFR/IFR CIGS BETWEEN 00-03Z FOR MOST
LOCATIONS.

VICINITY OF KSFO...IFR/MVFR THROUGH ABOUT 20Z. BREEZY ONSHORE
WINDS THIS AFTERNOON WITH GUSTS TO AROUND 20KT. MVFR CIGS RETURN
AFTER ABOUT 01Z WITH LOWERING CIGS POSSIBLE BY 06Z.

KSFO BRIDGE APPROACH...EARLIER BURN-OFF HAS ALREADY OCCURRED.
OTHERWISE...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...LOW LEVEL CLOUDS HAVE SCATTERED OUT
AT THIS TIME...YET CANNOT RULE OUT A BRIEF RETURN OVER KMRY
THROUGH ABOUT 20Z. ONSHORE WINDS INCREASE THROUGH THE AFTERNOON.
EARLY RETURN OF MVFR CIGS EXPECTED AROUND 00Z WITH LOWERING CIGS
LIKELY BEYOND 03Z.

&&

.MARINE...AS OF 08:39 AM PDT THURSDAY...HIGH PRESSURE ALONG THE
CALIFORNIA COAST WILL RESULT IN LIGHT TO LOCALLY MODERATE
NORTHWEST WINDS. THE STRONGEST WIND SPEEDS WILL BE THROUGH THE
NORTHERN SAN FRANCISCO BAY...OFF OF THE SONOMA COASTLINE AND ALONG
THE BIG SUR COASTLINE. PREDOMINATELY GENTLE SEAS WILL PERSIST
THROUGH THE FORECAST PERIOD.

&&

.BEACHES...AS OF 10:50 AM PDT THURSDAY...A WESTERLY SWELL OF 5 TO
7 FEET WITH A PERIOD AROUND 14 SECONDS WILL CONTINUE TO MOVE INTO
THE COASTAL WATERS TODAY. THE COMBINATION OF THIS SWELL AND
GENERALLY WEAK ONSHORE WINDS WILL RESULT IN AN INCREASED RISK OF
STRONG RIP CURRENTS ALONG AREA BEACHES THROUGH THIS EVENING.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...SCA...PT ARENA TO PT REYES 0-10 NM UNTIL 3 AM
             SCA...PIGEON PT TO PT PINOS 0-10 NM UNTIL 3 AM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM UNTIL 3 AM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM
             SCA...SF BAY NORTH OF THE BAY BRIDGE UNTIL 9 PM

&&

$$

PUBLIC FORECAST: LARRY
AVIATION/MARINE: RGASS

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