Weather Service Report


749 
FXUS66 KMTR 251749
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
949 AM PST TUE NOV 25 2014

.SYNOPSIS...SUNNY AND SEASONABLY WARM TODAY AND WEDNESDAY UNDER
STRONG HIGH PRESSURE. NICE WEATHER CONTINUES THANKSGIVING DAY AS
THE RIDGE BEGINS TO WEAKEN BRINGING TEMPERATURES BACK TO NORMAL.
FIRST FRONT MOVES INTO THE NORTH BAY LATER FRIDAY NIGHT INTO
EARLY SATURDAY. FRONT WILL THEN DROP SOUTHWARD THROUGH THE REST
OF THE BAY AREA AND CENTRAL COAST SATURDAY INTO SUNDAY WITH
PERIODS OF LIGHT TO LOCALLY MODERATE RAIN. MAIN COLD FRONTAL
PASSAGE NOW LOOKS TO OCCUR LATE SUNDAY NIGHT OR MONDAY MORNING
WHEN HEAVY RAIN WILL BE POSSIBLE.

&&

.DISCUSSION...AS OF 09:01 AM PST TUESDAY...CLEAR SKIES PREVAIL
ACROSS THE REGION THIS MORNING WITH A STRONG MID/UPPER LEVEL RIDGE
JUST OFF THE COAST. TEMPERATURES ARE ON TRACK TO WARM INTO THE
LOWER 70S NEAR THE COAST TO UPPER 70S INLAND THIS AFTERNOON WITH
WEAK OFFSHORE FLOW JUST OFF THE SURFACE. NO CHANGES ARE NEEDED TO
THE ONGOING FORECAST AT THIS TIME. WILL FOCUS OUR ATTENTION TO THE
UPCOMING STORM SYSTEM SET FOR THIS WEEKEND INTO EARLY NEXT WEEK. 

&&

.PREV DISCUSSION...AS OF 3:41 AM PST TUESDAY...SKIES ARE CLEAR
WITH TEMPERATURES GENERALLY IN THE 40S THIS MORNING. SOME OF THE
COLDEST SPOTS WILL DROP INTO THE UPPER 30S BEFORE SUNRISE WITH
DEW-POINTS STILL HOVERING AROUND 40 DEGREES. GRADIENTS STILL SHOW
OVER 1 MB OF OFFSHORE FROM SFO TO SAC WITH EAST WINDS MAKING IT
ALL THE WAY OUT TO THE BUOYS. UPSHOT IS STRONG HIGH PRESSURE WITH
LIGHT OFFSHORE FLOW LEADING TO SUNNY AND SEASONABLY WARM DAYS
THROUGH AT LEAST WEDS. LOOK FOR DAYTIME HIGHS FROM THE UPPER 60S
TO UPPER 70S WITH LITTLE VARIATION IN THE OVERALL WEATHER THROUGH
WEDS. GOOD NEWS FOR HOLIDAY TRAVELERS...AT LEAST IN CALIFORNIA
WITH NO FOG OR PRECIP TO WORRY ABOUT.

THE RIDGE WILL FLATTEN ON THANKSGIVING BUT WEATHER LOOKS NICE FOR
ANY OUTDOOR HOLIDAY PLANS. TEMPS WILL COOL SLIGHTLY AS THE FLOW
TURNS BACK TO ONSHORE MEANING MOST AREAS WILL STAY IN THE 60S ON
THURSDAY WITH LESS OF THE 70 PLUS TYPE WEATHER. NEED TO MENTION
THAT THE SEA SURFACE TEMP AT BUOY 26 HAS DROPPED TO 57 DEGREES
WHICH IS UNSEASONABLY MILD BUT HASN'T BEEN THAT LOW IN A LONG
TIME SO THE WINDS OFF THE OCEAN WILL HAVE A BIT OF CHILL.

OF COURSE WEATHER ITEM OF INTEREST STILL REMAINS THE RAIN CHANCES
THIS WEEKEND. MODEL CHANGES HAVE BEEN MINIMAL OVERALL. LATEST
THINKING SUGGESTS THE FIRST REAL CHANCE OF ANY RAIN WILL OCCUR IN
THE NORTH BAY ON FRIDAY NIGHT. IF ANYTHING THE MODEL TRENDS SEEM
TO BE SLOWING THINGS AS JET ENERGY DIGS OVER THE PACIFIC AND WITH
A FAIRLY AMPLIFIED PATTERN ACROSS THE UNITED STATE A SLOWER
EVOLUTION IS PLAUSIBLE.

RAIN CHANCES WILL INCREASE ACROSS THE BAY AREA AND CENTRAL COAST
THROUGH THE DAY SATURDAY BUT NEED TO STRESS THAT SOUTHERN THIRD
OF THE CWA COULD STAY DRY RIGHT THROUGH SATURDAY AS THE SYSTEM
DIGS OFF THE COAST. RAIN ON SATURDAY WILL BE WARM ADVECTION EVENT
WITH HIGH BASED CLOUDS AND REALLY ONLY EXPECTING PERIODS OF LIGHT
RAIN. EXCEPTION TO THAT WILL BE THE NORTH BAY WHERE OROGRAPHICS
AND TONGUE OF 1.25 PWAT MAY LINE UP BETTER.

ANYWAY THERE WILL LIKELY BE A LULL IN THE RAIN AT SOME POINT
LATER SATURDAY NIGHT OR INTO SUNDAY BEFORE THE NEXT ROUND OF
UPPER DYNAMICS AND JET ENERGY ARRIVES. FOR NOW ITS ALL JUST
COVERED WITH CONTINUED CHANCES OF RAIN ON SUNDAY.

IT DOES LOOK LIKE PRETTY GOOD CONSENSUS BETWEEN THE GFS/GEM AND
ECMWF THAT THE MAIN COLD FRONTAL PASSAGE WILL HOLD OFF UNTIL
SUNDAY NIGHT OR MONDAY MORNING. THIS IS WHEN THE SURFACE
FRONT...UPPER JET AND CORE OF COLD AIR ALOFT WILL FINALLY PASS
OVERHEAD. WHEN THIS OCCURS IS THE WINDOW OF WHEN WIDESPREAD HEAVY
RAIN WILL BE MOST LIKELY TO OCCUR. ITS STILL JUST TOO FAR OUT TO
FINE TUNE DETAILS BUT IF THE TREND IS OUR FRIEND THEN SLOWER
SOLUTIONS SEEM TO BE WINNING OUT IN TERMS OF BRINGING THE MOST
ACTIVE WEATHER THROUGH THE BAY AREA.

UPPER TROUGH AXIS MOVING THROUGH LATER MONDAY INTO TUESDAY KEEPS
SHOWER CHANCES IN THE FORECAST WITH A RIDGE BUILDING BACK IN BY
THE MIDDLE OF NEXT WEEK.

&&

.AVIATION...AS OF 9:50 AM PST TUESDAY...DRY AIRMASS CONTINUES
OVER THE AREA FOR VFR CONDITIONS TODAY. SOME PATCHY FOG COULD
DEVELOP NEAR SANTA ROSA NEAR SUNRISE TOMORROW. 

VICINITY OF KSFO...VFR.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR.

&&

.MARINE...AS OF 09:45 AM PST TUESDAY...HIGH PRESSURE WILL MOVE
INTO THE GREAT BASIN TONIGHT. WINDS WILL BECOME LIGHT EAST TO
SOUTHEAST BY WEDNESDAY AS A FRONTAL SYSTEM MOVES INTO THE PACIFIC
NORTHWEST. SOUTHERLY WINDS WILL INCREASE BY THE END OF THE WEEK AS
A STRONGER STORM APPROACHES THE AREA.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...NONE.

$$

PUBLIC FORECAST: RGASS
AVIATION/MARINE: SIMS

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