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

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000
FXUS66 KMTR 200529
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1029 PM PDT FRI SEP 19 2014

.SYNOPSIS...PLEASANT WEATHER IS ANTICIPATED THROUGH THE WEEKEND.
A PACIFIC STORM SYSTEM WILL BRING A POSSIBILITY OF PRECIPITATION
TO THE FORECAST AREA BY MID WEEK.

&&

.DISCUSSION...AS OF 9:00 PM PDT FRIDAY...WATER VAPOR SATELLITE
IMAGERY THIS EVENING SHOWS AN UPPER LOW OFF THE SOUTHERN CA
COAST...CENTERED ABOUT 100 MILES SW OF POINT CONCEPTION. THIS
CUTOFF LOW IS WHAT IS LEFT OF THE SYSTEM THAT BROUGHT RAIN TO
MUCH OF OUR REGION ON WEDNESDAY NIGHT AND THURSDAY MORNING. THE
AIRMASS NEAR THIS LOW CENTER REMAINS SOMEWHAT UNSTABLE...ENOUGH
FOR SCATTERED CUMULUS CLOUDS TO DEVELOP OVER THE MOUNTAINS OF
MONTEREY AND SAN BENITO COUNTIES THIS AFTERNOON. BUT NO SHOWER OR
THUNDERSTORM ACTIVITY DEVELOPED.

EASTERLY FLOW TO THE NORTH OF THE LOW CENTER HAS BEEN PUSHING
SMOKE FROM THE KING FIRE TO THE WEST TODAY...RESULTING IN REPORTS
OF HAZY SKIES AS FAR WEST AS THE SF BAY AREA BY SUNSET THIS
EVENING. LOOK FOR CONTINUED HAZY SKIES INTO THE WEEKEND AS THE
UPPER LEVEL FLOW IS FORECAST TO MAINTAIN AN EASTERLY COMPONENT
ACROSS NORTHERN AND CENTRAL CA THROUGH AT LEAST SATURDAY NIGHT.

A TROUGH OVER THE EASTERN PACIFIC NEAR 150W WILL ADVANCE SLOWLY
TOWARDS THE WEST COAST TONIGHT AND SATURDAY. BY LATE SATURDAY
THIS TROUGH WILL HAVE DRAWN CLOSE ENOUGH TO NUDGE THE UPPER LOW
TO THE ENE. THE LOW IS THEN FORECAST TO TRACK ACROSS SOUTH-
CENTRAL CA FROM LATE SATURDAY AFTERNOON THROUGH SATURDAY NIGHT.
AS THE LOW TRACKS ACROSS THE SOUTHERN END OUR FORECAST AREA LATE
ON SATURDAY THERE WILL PROBABLY ONCE AGAIN BE SUFFICIENT
INSTABILITY FOR CUMULUS DEVELOPMENT OVER THE HILLS OF MONTEREY AND
SAN BENITO COUNTIES. CURRENT FORECAST ALSO CALLS FOR A SLIGHT
CHANCE OF THUNDERSTORMS OVER FAR SOUTHERN SAN BENITO AND
SOUTHEASTERN MONTEREY COUNTIES LATE TOMORROW AFTERNOON. WILL LEAVE
THIS IN THE FORECAST FOR NOW GIVEN THAT THE 18Z GFS FORECASTS
GREATER INSTABILITY IN THAT AREA TOMORROW AFTERNOON COMPARED TO
TODAY. HOWEVER...IT SHOULD BE NOTED THAT THE 00Z NAM FORECASTS
LESS INSTABILITY. IN ANY CASE...MOST OF OUR AREA WILL EXPERIENCE A
MOSTLY SUNNY AND MILD DAY TOMORROW AFTER MORNING LOW CLOUDS
CLEAR...EXCEPT FOR HAZY CONDITIONS DUE TO SMOKE ALOFT. NOT MUCH
CHANGE IS FORECAST FOR SUNDAY EXCEPT BY THEN THE UPPER LOW WILL
HAVE MOVED WELL OFF TO OUR EAST AND WILL NO LONGER HAVE ANY IMPACT
ON OUR WEATHER. DAYTIME TEMPS OVER THE WEEKEND WILL BE NEAR
NORMAL. NIGHTTIME TEMPS WILL REMAIN ABOVE NORMAL...ESPECIALLY NEAR
THE COAST...DUE TO CONTINUED WELL ABOVE NORMAL COASTAL WATER
TEMPS.

THE MEDIUM RANGE MODELS HAVE BEEN CONSISTENT THE PAST FEW DAYS IN
MOVING THE LONGWAVE TROUGH OVER THE EASTERN PACIFIC GRADUALLY TO
THE EAST DURING THE FIRST HALF OF NEXT WEEK...AND SPREADING RAIN
ACROSS MUCH OF NORTHERN CALIFORNIA BY MIDWEEK.

&&

.AVIATION...AS OF 9:00 PM PDT FRIDAY...EVEN THOUGH THERE IS EXTENSIVE
STRATUS ALONG THE COAST AND THE ONSHORE GRADIENTS ARE STRONGER E-W...THE
MARINE LAYER IS SHALLOW AND WEAK AND THEREFORE IS NOT SPREADING
OVER THE HCOASTAL HILLS. LATEST FORECAST NOW BRINGS MVFR CIGS TO
SFO AFTER 06Z.

VICINITY OF KSFO...MVFR AFTER 06Z.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...STRATUS IS ALREADY POURING INTO THE
SRN MRY BAY AREA. IFR FOR CIGS.

&&

.MARINE...AS OF 10:30 PM PDT FRIDAY...MODERATE ONSHORE WINDS WILL
CONTINUE INTO THE EVENING HOURS. A FAIRLY LONG PERIOD
SOUTHWESTERLY SWELL WILL CONTINUE TO IMPACT THE WATERS INTO THE
EVENING BUT IS EXPECTED TO SLOWLY SUBSIDE OVER THE NEXT 24 HOURS.
A LONGER PERIOD WEST TO NORTHWEST SWELL IS FORECAST TO IMPACT OUR
AREA STARTING ON WEDNESDAY.

&&

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

&&

$$

PUBLIC FORECAST: DYKEMA
AVIATION/MARINE: W PI

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