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

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000
FXUS66 KMTR 030022
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
522 PM PDT TUE JUN 2 2015

.SYNOPSIS...DRY WEATHER WILL PERSIST THROUGH AT LEAST THURSDAY WITH
TEMPERATURES GENERALLY BELOW SEASONAL AVERAGES. AN UPPER LEVEL LOW
WILL BRING THE POSSIBILITY OF SHOWERS THIS WEEKEND.

&&

.DISCUSSION...AS OF 3:00 PM PDT TUESDAY...ONSHORE FLOW HAS
INCREASED TODAY AND TEMPERATURES AROUND THE BAY ARE RUNNING A FEW
DEGREES COOLER THAN YESTERDAY WHILE INLAND TEMPERATURES ARE ABOUT
THE SAME. LOW CLOUDS LINGERING OVER THE PENINSULA HILLS AND THIS
WILL BE THE SPREADING POINT OF THE STRATUS INTO THE SFO BAY AREA
TONIGHT.

WEAK UPPER LEVEL TROFFING WILL CONTINUE OVER THE AREA WEDNESDAY.
LITTLE CHANGE IN THE WEATHER IS EXPECTED EXCEPT MODELS SHOWING
LESS LOW LEVEL MOISTURE SO STRATUS MAY CLEAR A LITTLE SOONER WHICH
WOULD ALLOW TEMPERATURES TO WARM SLIGHTLY NEAR THE COAST.

THE UPPER TROUGH STARTS TO DEEPEN AND SLIDE DOWN THE WEST COAST ON THURSDAY
FORMING INTO A CUTOFF LOW OVER CENTRAL OR SOUTHERN CALIFORNIA
FRIDAY. THIS WILL BRING COOLER TEMPERATURES TO THE AREA. LATEST
NAM MODEL SHOWS DECENT CAPE VALUES OF OVER 600 J/KG OVER THE NORTH
BAY HILLS OF NORTHEAST SONOMA COUNTY AND NORTHERN NAPA COUNTY FRIDAY
AFTERNOON. THE QUESTION IS WHETHER THERE IS ENOUGH MOISTURE TO
PRODUCE ISOLATED CONVECTIVE SHOWERS. THE LOW IS FORECAST TO
ENTRAIN SOME TROPICAL MOISTURE FROM THE DYING TROPICAL STORM
ANDRES BUT MOST OF THE MOISTURE WILL REMAIN EAST OF THE AREA. SO
CHANCES ARE LOW FOR GETTING ANY SHOWERS BUT HAVE MENTIONED A
SLIGHT CHANCE OF SHOWERS FOR THIS CORNER OF THE CWA.

THE UPPER LOW WILL SPIN IN PLACE OVER SOUTHERN CALIFORNIA SATURDAY
AND SUNDAY. THE INSTABILITY AND POTENTIAL MOISTURE WARRANTS
MENTIONING A SLIGHT CHANCE OF SHOWERS OVER THE DISTRICT. THE UPPER
LOW WILL MOVE INLAND EARLY NEXT WEEK BUT MODELS ARE FORECASTING
ANOTHER WEAK UPPER LEVEL TROUGH WILL BREAK OFF AND REMAIN OFF THE
COAST THROUGH MIDWEEK. UNDER SOUTHWESTERLY FLOW ALOFT THE THREAT
OF CONVECTION WILL END AND TEMPERATURES WILL WARM UP.

&&

.AVIATION...AS OF 5:00 PM PDT TUESDAY...A NEARLY 4 MB GRADIENT
FROM SFO-ACV HAS CLEARED MOST OF THE STRATUS FROM THE COAST THIS
AFTERNOON. LOW CLOUDS ARE NOT EXPECTED TO MAKE AN EARLY RETURN
THIS EVENING BUT RATHER HOLD OFF TILL AFTER MIDNIGHT TONIGHT
ACROSS MOST TERMINALS. STRATUS WILL SCATTER OUT BY NOON WEDNESDAY.
WINDS WILL REMAIN STRONG AND GUSTY THROUGH LATE THIS EVENING THEN
EASE OVERNIGHT. GUSTY ONSHORE FLOW WILL RETURN AGAIN WEDNESDAY
AFTERNOON. MODERATE CONFIDENCE.

VICINITY OF KSFO...VFR CONDITIONS WILL PREVAIL THROUGH LATE
TONIGHT. IFR CIGS ARE ANTICIPATED TO RETURN AROUND 08Z AND 10Z
OVER KOAK AND KSFO RESPECTIVELY. CIGS WILL SCATTER OUT AROUND 19Z.
A MODERATELY STRONG ONSHORE FLOW BETWEEN 15 TO 20 KT WITH GUSTS TO
NEAR 30 KT WILL CONTINUE THROUGH THIS EVENING. WINDS WILL EASE TO
UNDER 10 KT OVERNIGHT. GUSTY SEABREEZE WILL RETURN AGAIN WEDNESDAY
AFTERNOON.

KSFO BRIDGE APPROACH... SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WILL PREVAIL THROUGH LATE
TONIGHT. IFR CIGS ARE ANTICIPATED TO RETURN AROUND 06Z WITH
CLEARING AROUND 18Z-19Z WEDNESDAY. MODERATELY LIGHT ONSHORE FLOW
BETWEEN 10 TO 15 KT WILL CONTINUE THROUGH THIS EVENING. WINDS WILL
EASE TO AROUND 5 KT OVERNIGHT. GUSTY SEABREEZE WILL RETURN AGAIN
WEDNESDAY AFTERNOON.

&&

.MARINE...AS OF 1:44 PM PDT TUESDAY...NORTHWEST WINDS WILL
INCREASE THROUGH THIS AFTERNOON AS HIGH PRESSURE STRENGTHENS OVER
THE COASTAL WATERS. THE STRONGEST WINDS WILL BE ALONG SHORE OF THE
SONOMA... SANTA CRUZ... AND MONTEREY COASTLINES. GUSTY WINDS WILL
PERSIST THROUGH FRIDAY WITH HAZARDOUS CONDITIONS AND STEEP WIND
WAVES.

&&

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

&&

$$

PUBLIC FORECAST: W PI
AVIATION: CW
MARINE: DRP

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