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

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000
FXUS66 KMTR 060457
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
957 PM PDT SUN JUL 5 2015

.SYNOPSIS...A RATHER DEEP MARINE LAYER WILL REMAIN IN PLACE AND
RESULT IN WIDESPREAD NIGHT AND MORNING CLOUDS...PATCHY FOG AND
COASTAL DRIZZLE THROUGH MIDWEEK. TEMPERATURES WILL ALSO TREND COOLER
THROUGH MUCH OF THE WORKWEEK AS AN UPPER LEVEL SYSTEM APPROACHES THE
CALIFORNIA COAST.

&&

.DISCUSSION...AS OF 9:00 PM PDT SUNDAY...IN MOST CASES
TEMPERATURES ENDED UP BEING COOLER COMPARED TO YESTERDAY WITH MANY
INLAND SPOTS ONLY GETTING INTO THE UPPER 70S TO LOWER 80S WHICH IS
A DROP OF UP TO 13 DEGREES. COASTAL AREAS WERE GENERALLY CLOSE TO
WHERE THEY WERE YESTERDAY -- 60S TO LOWER 70S. WORTH POINTING OUT
THAT THE MONTEREY BAY BUOY HIT 64 DEGREES TODAY FOR WATER TEMP
WHICH IS 7 TO 8 DEGREES ABOVE NORMAL. THE WARMER THAN NORMAL SEA
TEMPS WILL HELP TO KEEP COASTAL SPOTS FAIRLY MILD AT NIGHT.

SATELLITE LOOPS OVER THE PAST FEW HOURS HAVE SHOWED THE TYPICAL
SUMMERTIME PATTERN WITH CLOUDS FIRST ADVANCING TO THE COAST THEN
SLOWLY HEADING INLAND. WITH A MARINE LAYER OVER 2000 FEET PLUS A
MODERATE WESTERLY SURFACE FLOW WOULD EXPECT TO SEE WIDESPREAD
CLOUDS WITH PATCHY FOG TONIGHT. PATCHY DRIZZLE IS ALSO LIKELY AT
THE COAST. ONE MEMBER OF THE PUBLIC PICKING UP 0.06" THIS MORNING
IN SONOMA COUNTY DUE TO DRIZZLE.

FOR THE FORECAST...AN UPDATE FOR HIGHS WERE DONE EARLIER THIS
EVENING WHICH GENERALLY DROPPED EXPECTED NUMBERS FOR INLAND SPOTS
BY A FEW DEGREES FOR BOTH MONDAY AND TUESDAY BASED OFF OF WHAT WE
SAW TODAY. SYNOPTICALLY AN UPPER LEVEL LOW TO OUR WEST WILL
SLOWLY PROGRESS TOWARD OUR CWA THROUGH THURSDAY. WORTH NOTING THAT
THE ECMWF DOES BRING SOME LIGHT RAIN TO THE NORTH BAY ON THURSDAY
AS THE LOW MOVES OVER OUR CWA. WILL LET THE MIDNIGHT CREW TAKE A
CLOSER LOOK AT THAT. FOR NOW WILL KEEP THE MENTION OF DRIZZLE FOR
OVERNIGHT PERIODS GOING FOR MOST OF THE WEEK. TEMPS WILL GENERALLY
BE NEAR TO SLIGHTLY BELOW NORMAL.

REST OF THE FORECAST APPEARS TO BE ON TRACK.

.PREVIOUS DISCUSSION...AN UPPER LEVEL LOW REMAINS ABOUT 500 MILES
TO THE WEST- SOUTHWEST OF SAN FRANCISCO THIS AFTERNOON. THIS
SYSTEM HAS AIDED IN THE DEEPENING OF THE MARINE LAYER THAT APPEARS
TO BE AROUND 2500 FEET DEEP VIA THE FORT ORD PROFILER. GIVEN THE
DEEP MARINE LAYER AND LIGHT ONSHORE FLOW...LOW LEVEL CLOUDS WILL
ONCE AGAIN PUSH INLAND DURING THE EARLY EVENING HOURS AND SPREAD
INTO MOST VALLEY LOCATIONS BY MONDAY MORNING. IN ADDITION TO THE
LOW CLOUDS...PATCHY FOG AND DRIZZLE WILL ONCE AGAIN BE LIKELY
ALONG COASTAL LOCATIONS OVERNIGHT AND INTO MONDAY MORNING. MOST
PLACES WILL LIKELY ONLY RECEIVE A TRACE OF PRECIPITATION...HOWEVER
CANNOT RULE OUT A FEW SPOTS PICKING UP A FEW HUNDREDTHS OF AN
INCH.

THE UPPER LEVEL LOW IS FORECAST TO SLOWLY APPROACH THE CALIFORNIA
COAST DURING THE FIRST HALF OF THE WEEK. THIS WILL MAINTAIN A
STRONG MARINE INFLUENCE WITH CONTINUED LOW CLOUDS...PATCHY FOG AND
THE POTENTIAL FOR COASTAL DRIZZLE EACH MORNING. AS THE LOW
APPROACHES THE COAST...TEMPERATURES WILL ALSO COOL ALOFT AND
TRANSLATE TO COOLER INLAND TEMPERATURES THROUGH MIDWEEK. ASIDE
FROM PATCHY COASTAL DRIZZLE...DRY WEATHER CONDITIONS ARE EXPECTED
FOR MOST INLAND LOCATIONS. THE FORECAST MODELS THEN HIT AND A
SLIGHT CHANCE OF LIGHT PRECIPITATION ON THURSDAY AND/OR FRIDAY AS
THE CENTER OF THE UPPER LEVEL LOW MOVES OVER THE REGION.
HOWEVER...THERE STILL APPEARS TO BE A LACK OF MOISTURE AND
INSTABILITY FOR WIDESPREAD PRECIPITATION AS THE SYSTEM MOVES
INLAND LATE IN THE WEEK. WILL MAINTAIN A DRY FORECAST AT THIS TIME
UNTIL THERE IS BETTER CONSISTENCY IN THE MODELS.
OTHERWISE...TEMPERATURES OVER THE REGION WILL GENERALLY BE ON THE
COOL SIDE OF NORMAL FOR THE REMAINDER OF THE WEEK GIVEN THE COOLER
AIR MASS ALOFT.

THE UPPER LEVEL LOW WILL FINALLY SHIFT INLAND AND LIFT NORTHEAST
BY NEXT WEEKEND. THIS WILL END ANY CHANCES OF PRECIPITATION AND
RESULT IN A SLIGHT INLAND WARMING TREND LATE IN THE FORECAST
PERIOD. GENERALLY EXPECT DRY WEATHER TO RETURN ALONG WITH
TEMPERATURES NEAR SEASONAL AVERAGES.

&&

.AVIATION...AS OF 9:57 PM PDT SUNDAY...THE EPAC LOW IS BEGINNING
TO MOVE SLOWLY EAST. AS A RESULT ADDITIONAL WEAK LOW TO MID LEVEL
COOLING IS FORECAST TONIGHT AND MONDAY. THE MARINE LAYER CLOUDS
WILL CONTINUE TO MOVE INLAND TONIGHT.

VICINITY OF KSFO...MVFR CIG IS FORECAST UNTIL 17Z. VFR IS LIKELY
TO RETURN BY LATE MONDAY MORNING.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...MVFR CIGS TONIGHT. VFR IS FORECAST
TO RETURN BY LATE MONDAY MORNING.

&&

.MARINE...AS OF 8:10 PM PDT SUNDAY...GUSTY AFTERNOON AND EVENING
WINDS ARE EXPECTED OVER THE SAN FRANCISCO BAY NORTH OF THE BAY
BRIDGE MONDAY AND POSSIBLY AGAIN TUESDAY. OTHERWISE GENERALLY
LIGHT WINDS AND SEAS ARE EXPECTED OVER THE COASTAL WATERS THIS
WEEK. A LONG PERIOD SOUTHWESTERLY SWELL ARRIVES FROM THE SOUTHERN
HEMISPHERE EARLY THIS WEEK.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...NONE.

&&

$$

PUBLIC FORECAST: BELL/RGASS
AVIATION/MARINE: CANEPA


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