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

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000
FXUS66 KMTR 160531
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1031 PM PDT MON SEP 15 2014

.SYNOPSIS...A GRADUAL COOLING TREND WILL CONTINUE OVER INLAND
AREAS ON TUESDAY AHEAD OF AN APPROACHING TROUGH. THIS SYSTEM WILL
BRING A SLIGHT CHANCE OF SHOWERS TO THE NORTH BAY AND SAN
FRANCISCO BAY AREA LATE WEDNESDAY INTO EARLY THURSDAY. SHOWER CHANCES
THEN END AND TEMPERATURES REBOUND FOR THE UPCOMING WEEKEND.

&&

.DISCUSSION...AS OF 9:47 PM PDT MONDAY...SKIES ARE MOSTLY CLEAR
THIS EVENING EVEN THOUGH THE WIND FLOW IS DISTINCTLY ONSHORE WITH
CYCLONIC FLOW ALOFT OVER THE OCEAN. THE SST ARE NOW A SOLID 65
DEGREES...UNSEASONABLY WARM AND THE MARINE INVERSION LAYER ISN`T
REFORMING LIKE IT USUALLY DOES WITH LARGER SURFACE TO 850 MB DELTA T.
ANYWAY STILL EXPECT MARINE CLOUDS TO SLOWLY REFORM OVERNIGHT AND
THROUGH MORNING WITH INCREASING WESTERLY WIND FLOW AHEAD OF THE
SYSTEM.

BATCH OF MOISTURE CLEARLY SHOWS UP ON IR SATELLITE OUR NEAR
35N/135W WITH JET STREAM ENERGY DROPPING DOWN THE BACKSIDE OF THE
TROUGH. THIS WILL SLOW ANY EASTWARD PROGRESSION AS WILL TS ODILE
AND THE RIDGE OVER THE WESTERN US.

MAIN RAIN BAND WILL STAY FOCUSED NORTH OF THE BAY AREA AND HEAD
TOWARDS CAPE MENDOCINO BY WEDS AFTERNOON. HOWEVER AS THIS OCCURS
THE SYSTEM WILL STALL OUT AND NOW PRETTY GOOD MODEL CONSENSUS FOR
GENERATING SOME LIGHT AND SPOTTY SHOWERS OVER THE NORTH BAY LATER
WEDS EVENING INTO EARLY THURSDAY MORNING. ANY QPF LOOKS TO BE ON
THE ORDER OF A FEW HUNDREDTHS WITH LITTLE OR NO CHANCE OF PRECIP
SOUTH OF THE GOLDEN GATE (OR PERHAPS THE SANTA CRUZ MOUNTAINS).
MOS GUIDANCE HAS POPS AS HIGH AS 40% FOR SANTA ROSA TO AROUND 20%
FOR SAN JOSE BUT AGAIN LITTLE HOPE FOR MORE THAN A FEW LIGHT RAIN
SHOWERS.

THE JUICY AND SOMEWHAT PROMISING WEATHER SYSTEM GETS CUT-OFF AND
BECOMES MORIBUND BY THURSDAY AFTERNOON AS RIDGING BUILDS IN FROM
THE WEST. THE UPPER LOW WILL DROP DOWN THE COAST AND THE BAY AREA
WILL BECOME UNDER THE INFLUENCE OF NORTHEASTERLY FLOW AROUND THE
UPPER LOW AND BUILDING HIGH PRESSURE FROM THE WEST. THIS WILL SET
THE STAGE FOR A SUNNY AND WARM TO HOT WEEKEND WITH 850 MB TEMPS
AROUND 24 CELSIUS...THERMAL TROUGH NEAR THE COAST...590 DM HIGH
OVER NORCAL AND SYNOPTIC EASTERLY FLOW OVER CENTRAL CALIFORNIA
ROTATING AROUND THE UPPER LOW.

&&

.AVIATION...AS OF 10:30 PM PDT MONDAY...VFR HELD TOGETHER WELL
THROUGH THE EVENING BUT NOW BEGINNING TO SEE SOME PATCHES OF LOW
CLOUDS DEVELOPING FROM POINT REYES TO SAN FRANCISCO. AIRMASS
STABILITY...NOCTURNAL RADIATIONAL COOLING AND LIGHT WINDS WILL
ALLOW FOR ADDITIONAL LOW CLOUD DEVELOPMENT THROUGH THE NIGHT-TIME
HOURS. THE USUAL CLEARING BACK TO THE COAST BY LATE MORNING OR EARLY
AFTERNOON IS EXPECTED TUESDAY.

VICINITY OF KSFO...VFR TIL 10Z. MVFR CIG POSSIBLE FROM 10Z-17Z.
VFR RETURNS LATE TUESDAY MORNING.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR STILL HOLDING THIS EVENING. LOW
CLOUDS ARE EXPECTED TO DEVELOP OVERNIGHT. IFR FORECAST TO
DEVELOP 07Z-09Z.

&&

.MARINE...AS OF 10:30 PM PDT MONDAY...LIGHT WINDS WILL CONTINUE
THROUGH MUCH OF THE WEEK. A LONG PERIOD SOUTHWEST SWELL WILL
CONTINUE THROUGH MIDWEEK...OCCASIONALLY MIXING WITH NORTHWEST
SWELL THURSDAY AND AGAIN NEXT WEEKEND. SOUTHWEST SWELL WILL PEAK
WEDNESDAY NIGHT INTO THURSDAY.

&&

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

&&

$$

PUBLIC FORECAST: RWW
AVIATION/MARINE: CANEPA

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