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

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000
FXUS66 KMTR 011724
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1024 AM PDT WED OCT 1 2014

.SYNOPSIS...BREEZY OFFSHORE WINDS IN THE HILLS THIS MORNING WILL
EASE BY MIDDAY. UNDER SUNNY SKIES EXPECT MUCH WARMER TEMPERATURES
THIS AFTERNOON WITH HIGHS INTO THE 80S AND LOWER 90S FOR MOST OF
THE BAY AREA. WARM TO HOT WEATHER WILL CONTINUE THURSDAY AND
THROUGH THE WEEKEND WITH STRONG HIGH PRESSURE CENTERED OVER
CALIFORNIA. SOME SUBTLE COOLING WILL RETURN BY EARLY NEXT WEEK AS
ONSHORE FLOW RETURNS AHEAD OF THE NEXT UPPER TROUGH.

&&

.DISCUSSION...AS OF 9:00 AM PDT WEDNESDAY...OFFSHORE WINDS,
BUILDING RIDGE OF HIGH PRESSURE, AND WARMING ALOFT SHOULD ALL
COMBINE TO BRING SOME OF THE HOTTEST TEMPERATURES OF THE YEAR.
BASED OFF OF ECMWF GUIDANCE PLUS ANALOGS AND SYNOPTIC PATTERN,
DECIDED TO ISSUE A HEAT ADVISORY FOR ALL SPOTS FOR THURSDAY AND
FRIDAY. WIDESPREAD 80S TO POSSIBLY LOWER 90S DOWN TO THE BEACHES
WITH MOST INLAND SPOTS IN THE 90S TO LOWER 100S. SATURDAY COULD
ALSO BE WARM ENOUGH SO THE ADVISORY MAY NEED TO BE EXTENDED FOR
THAT DAY AS WELL.

REST OF FORECAST LOOKS TO BE ON TRACK -- NO SIGN OF ANY RAIN
THROUGH NEXT WEEK.

.PREVIOUS DISCUSSION...LOOKS LIKE THE COAST IS
CLEAR. THE NORTHERLY GRADIENT IS 6 MB DOWN THE COAST AND ABOUT 7 MB
FROM SFO-WMC...SETTING THE STAGE FOR A CLASSIC EARLY FALL OFFSHORE
WIND EVENT AND ASSOCIATED WARMING TREND ACROSS THE BAY AREA. SO
FAR SOME OF THE OF THE STRONGEST WIND GUSTS HAVE BEEN 47 MPH ON MT
DIABLO...38 MPH AT KNOXVILLE CREEK AND 27 MPH ON MT TAMALPAIS. AT
THIS TIME THE STRONGEST WINDS ARE GENERALLY STAYING ABOVE 2000
FEET BUT THE LAST REPORT OUT OF OAKLAND NORTH AT 1400 FEET HAD A
GUST TO 33 MPH. AS THE SUN COMES UP SOME OF THE WINDS WILL MIX
DOWN AS THE MORNING INVERSION BREAKS. THE STRONGEST WINDS WILL END
BY LUNCHTIME FOLLOWED BY A SUNNY AND WARM TO HOT AFTERNOON ACROSS
THE DISTRICT AS LIGHT OFFSHORE FLOW CONTINUES THROUGH THIS
AFTERNOON AND INTO TONIGHT.

A VERY DRY AIRMASS WILL SPREAD OVER THE REGION TONIGHT WITH
PERSISTENT BUT LIGHT OFFSHORE FLOW. EXPECT VERY POOR HUMIDITY
RECOVERY WHICH WILL BE A FIRE WEATHER CONCERN. IN GENERAL
OVERNIGHT LOWS WILL STAY FAIRLY MILD IN THE 50S AND LOWER 60S. THE
PERSISTENT NORTH WINDS OVER THE OCEAN HAS FINALLY ALLOWED SOME
UPWELLING TO OCCUR WITH BUOY 14 SHOWING A 3 DEGREE SST DROP IN THE
LAST 24 HOURS...THIS WILL ALLOW AT LEAST A FEW DEGREES MORE OF
COOLING NEAR THE COAST AS WERE ALREADY SEEING 54 IN MONTEREY WHICH
IS CLOSER TO NORMAL INSTEAD OF THE 60 DEGREE READINGS WE`VE SEEN OF LATE.

ANYWAY THE STRONG HIGH WILL REALLY TAKE HOLD THURSDAY AND FRIDAY
WITH A 594 DM HIGH CENTERED OVER SOUTHERN CALIFORNIA BUT THE 592
DM LINE PASSING THROUGH THE BAY AREA. THIS IN COMBINATION WITH
LIGHT OFFSHORE OR NEUTRAL GRADIENTS WILL ALLOW FOR WIDESPREAD 80
AND 90 DEGREE READINGS ACROSS THE DISTRICT. HEAT SENSITIVE
POPULATIONS SHOULD TAKE EXTRA PRECAUTIONS WITH FIRE WEATHER
CONCERNS REMAINING ELEVATED AS WELL. AT THIS TIME FRIDAY STILL
LOOKS TO BE THE HOTTEST DAY BUT WERE REALLY SPLITTING HAIRS IN
THAT BOTH THURSDAY AND SATURDAY LOOK SIMILARLY WARM TO HOT AS WELL.

ANY COOLING OF NOTE WILL LIKELY HOLD OFF UNTIL ABOUT MONDAY OF
NEXT WEEK AS ONSHORE WINDS RETURN...AT LEAST CLOSE TO THE COAST.

&&

.AVIATION...AS OF 10:15 AM PDT WEDNESDAY...CLEAR SKIES UNDER LIGHT
OFFSHORE FLOW. VFR TO CONTINUE THROUGH THE FORECAST PERIOD WITH
MOSTLY LIGHT WINDS. HIGH CONFIDENCE.

VICINITY OF KSFO...VFR. LATE SEABREEZE THIS AFTERNOON...OTHERWISE
LIGHT WINDS.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR. LIGHT WINDS.

&&

.CLIMATE...RECORD HIGH TEMPERATURES FOR WEDNESDAY THROUGH FRIDAY
(10/1 TO 10/3) ALONG WITH THE MOST RECENT DATE IT OCCURRED.

SF BAY AREA
.LOCATION.................10/1...........10/2............10/3...
 KENTFIELD................97/2012.......100/2012.........99/2012
 SAN RAFAEL..............104/1980.......106/1980........105/1980
 NAPA....................106/1980.......102/1980........103/1917
 SAN FRANCISCO............97/1980........96/1980.........97/1985
 SFO AIRPORT..............97/1980........96/1980.........94/1985
 OAKLAND (DOWNTOWN)......103/1980.......103/1980........100/1985
 OAKLAND AIRPORT..........94/1952........98/1980.........95/1985
 RICHMOND.................99/1980.......100/1980.........97/2012
 LIVERMORE...............102/1952.......106/1980........106/1980
 MOFFETT FIELD............93/1980........95/2012.........97/1985
 SAN JOSE.................97/1980........96/2012.........97/1985
 GILROY..................104/2001.......107/1980........106/1980

MONTEREY BAY AREA
.LOCATION.................10/1...........10/2............10/3...
 MONTEREY................103/1980.......101/1980.........96/1985
 SANTA CRUZ..............102/1965.......102/1980........102/1980
 SALINAS.................104/1980.......100/1980.........97/1985
 SALINAS AIRPORT.........105/1980.......103/1980.........99/1985
 KING CITY...............109/1980.......107/1980........102/1980

&&

.MARINE...AS OF 3:07 AM PDT WEDNESDAY...HIGH PRESSURE WILL BUILD
OVER THE GREAT BASIN RESULTING IN DECREASING NORTHWEST WINDS. A
LONG PERIOD SOUTHWEST SWELL WILL ARRIVE LATE IN THE WEEK.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...SCA...PT ARENA TO PT REYES 10-60 NM

&&

$$

PUBLIC FORECAST: BELL/RWW
AVIATION: AC
MARINE: W PI
CLIMATE: BELL

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