000
FXUS66 KMTR 061003
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
303 AM PDT MON SEP 6 2010
.DISCUSSION...AS OF 3:00 AM PDT MONDAY...SKIES ARE CLEAR ACROSS THE
ENTIRE REGION EARLY THIS LABOR DAY MORNING...EXCEPT FOR A PATCH OF
LOW CLOUDS IN MONTEREY BAY. LATEST FORT ORD PROFILER DATA SHOW A
SHALLOW MARINE INVERSION AT ABOUT 1000 FEET WITH OFFSHORE FLOW
ABOVE THE INVERSION. REMOTE WEATHER SENSORS IN THE HILLS INDICATE
THAT NORTH TO NORTHEAST WINDS HAVE DEVELOPED ABOVE 1000 FEET AND
THESE OFFSHORE WINDS ARE PICKING UP SPEED IN THE NORTH AND EAST BAY
WHERE GUSTS UP TO 30 MPH ARE PRESENTLY BEING REPORTED. SURFACE
WINDS HAVE NOT YET TURNED OFFSHORE AND THE GRADIENT FROM SFO TO SAC
IS STILL 1.6 MB ONSHORE. HOWEVER...THE ACV-SFO AND WMC-SFO
GRADIENTS ARE SHOWING A LARGER-SCALE OFFSHORE FLOW WHICH WILL
PREVENT A SEABREEZE FROM DEVELOPING FOR MUCH OF THE DAY...KEEP SKIES
SUNNY EVEN AT THE OCEAN BEACHES TODAY...AND WARM TEMPERATURES ALL
THE WAY TO THE COAST. HIGHS TODAY WILL RANGE FROM THE 70S NEAR THE
OCEAN...80S AROUND SF BAY...AND LOW TO MID 90S IN THE INLAND
VALLEYS.
TODAY MARKS THE UNOFFICIAL END TO SUMMER...AND OUR WEATHER WILL
DEFINITELY BECOME MUCH LESS SUMMER-LIKE OVER THE NEXT TWO DAYS. A
COLD WEATHER SYSTEM PRESENTLY DROPPING SOUTH ALONG THE COAST OF
BRITISH COLUMBIA IS FORECAST TO CONTINUE DIGGING SOUTH ALONG THE WEST
COAST OVER THE NEXT THREE DAYS. TEMPERATURES WILL PLUMMET ACROSS
OUR REGION ON TUESDAY AS BRISK ONSHORE FLOW DEVELOPS AHEAD OF THE
APPROACHING TROUGH. IN ADDITION...A MARINE LAYER WILL BEGIN TO RE-
FORM ALONG THE COAST. HIGH TEMPERATURES ON TUESDAY WILL BE ABOUT 15
TO 20 DEGREES BELOW WHAT IS FORECAST FOR TODAY. THE MARINE LAYER WILL
DEEPEN TUESDAY NIGHT AND SURGE INLAND AS A STRONG VORT MAX ROTATES
THROUGH THE BASE OF THE UPPER TROUGH AND APPROACHES THE SF BAY AREA.
LOW CLOUDS WILL SPREAD WELL INLAND AND LOCAL DRIZZLE IS LIKELY
TUESDAY NIGHT AND EARLY WEDNESDAY. 850 MB TEMPERATURES ARE FORECAST
TO COOL FROM ABOUT 21 DEG C AT THE PRESENT TIME DOWN TO ABOUT 7
DEGREES C BY MIDDAY WEDNESDAY. MOST COASTAL COOLING WILL OCCUR ON
TUESDAY...BUT INLAND AREAS WILL SEE ADDITIONAL COOLING ON WEDNESDAY.
THE FORECAST HIGH IN LIVERMORE ON WEDNESDAY IS ONLY 70 DEGREES...
WHICH IS 17 DEGREES BELOW THE NORMAL FOR THE DATE.
THE UPPER TROUGH WILL LIKELY BE VIGOROUS ENOUGH TO MIX OUT THE MARINE
LAYER ON WEDNESDAY AND WE CAN EXPECT MOSTLY SUNNY SKIES BY
THAT AFTERNOON. BUT THE LOW LEVELS WILL REMAIN MOIST AND WITH BRISK
ONSHORE FLOW WE'LL LIKELY CONTINUE TO SEE EXTENSIVE NIGHT AND
MORNING CLOUDINESS.
TEMPERATURES WILL WARM THURSDAY AND FRIDAY AS THE TROUGH MOVES OFF
TO THE EAST. EVEN SO...OUR WEATHER WILL CONTINUE TO BE COOLER THAN
NORMAL AS WE MOVE INTO NEXT WEEKEND. THE MEDIUM RANGE MODELS
DIVERGE SOMEWHAT NEXT WEEKEND. THE GFS FORECASTS A FLAT RIDGE OVER
THE WEST WHILE THE ECWMF DEVELOPS YET ANOTHER TROUGH ALONG THE WEST
COAST.
&&
.AVIATION...AS OF 10:18 PM PDT SUNDAY...LOW PRESSURE DIVING INTO THE
GREAT BASIN COMBINED WITH A THERMAL TROUGH DEVELOPING OVER
CALIFORNIA WILL RESULT IN OFFSHORE FLOW OVERNIGHT. THE OFFSHORE
FLOW WILL PRECLUDE ANY FORMATION OF STRATUS FROM THE TERMINALS
OVER THE NEXT 24 HOURS. HOWEVER...THERE WILL BE A POSSIBILITY
OF A BRIEF PERIOD OF CIGS AT THE MONTEREY AND SALINAS TERMINALS LATE
TONIGHT AS TEMPERATURES REACH THEIR DEWPOINTS.
.VICINITY OF KSFO...VFR TONIGHT THROUGH MONDAY EVENING. LIGHT
VARIABLE WINDS WILL INCREASE OUT OF THE WEST TOMORROW AFTERNOON TO 10
TO 15 KT BY 2000Z.
.KSFO BRIDGE APPROACH...VFR TODAY THROUGH MONDAY MORNING.
.MRY BAY AREA TERMINALS...VFR WITH SOME PATCHY FOG DEVELOPING LATE
THIS EVENING. A PERIOD OF LIFR WILL BE POSSIBLE BETWEEN 1200Z AND
1600Z MONDAY MORNING. VARIABLE WINDS WILL INCREASE TO 5 TO 10 KT BY
2000Z TOMORROW.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDA...SCA...PT ARENA TO PIGEON PT 10-60 NM
&&
$$
PUBLIC FORECAST: DYKEMA
AVIATION/MARINE: LARRY
Prepared by Boulder-Creek.com Weather at: Mon Sep 6 04:10:02 PDT 2010
From the National Weather Service
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