000
FXUS66 KMTR 280523
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
945 PM PST MON DEC 27 2010
.DISCUSSION...AS OF 9:00 PM PST MONDAY...INCREASING CLOUD COVER IS
ANTICIPATED TONIGHT AHEAD OF A STORM SYSTEM MOVING INTO NORTHERN
CALIFORNIA. A CHANCE OF SHOWERS IS POSSIBLE OVER THE HILLS OF THE
NORTH BAY OVERNIGHT AS THIS SYSTEM NEARS.
THE GFS AND THE ECMWF ARE IN FAIRLY GOOD AGREEMENT WITH THE TIMING
AND TRAJECTORY OF THIS STORM SYSTEM. HOWEVER THE 00Z RUN OF THE GFS
REMAINS A BIT STRONGER AND WETTER THEN THE 12Z RUN OF THE ECMWF.
WILL BE INTERESTED TO SEE WHAT THE 00Z RUN OF THE ECMWF SHOWS. THE
00Z RUN OF THE NAM IS SOMEWHERE IN BETWEEN THESE TWO SOLUTIONS.
EITHER WAY THIS STORM WILL BRING PLENTY OF RAIN TO THE AREA TUESDAY
AFTERNOON INTO TUESDAY NIGHT AS THE RAIN SPREADS SOUTH ACROSS THE
REGION. RAIN IS EXPECTED TO BE HEAVY AT TIMES THROUGH THE LATE
AFTERNOON AND EVENING.
ANOTHER VARIABLE TO CONSIDER WILL BE THE WINDS. CURRENT FORECAST
GUIDANCE INDICATES THE POTENTIAL FOR STRONG AND GUSTY WINDS TO
ACCOMPANY THIS STORM SYSTEM. THE JET AXIS IS ANTICIPATED TO LINE UP
PERPENDICULARLY TO THE COAST WITH THE LEFT EXIT REGION OF THE JET
OVER THE BAY AREA OVERNIGHT. A WIND ADVISORY MAY BE IN ORDER FOR
TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. ALONG WITH STRONG AND GUSTY
WINDS ENHANCED DIVERGENCE ALOFT WILL INCREASE THE POTENTIAL FOR HEAVY
DOWN POURS ACROSS THE REGION AS THIS SYSTEM MOVES TO THE SOUTH
TUESDAY NIGHT.
FROM PREVIOUS DISCUSSION...
A STRONG COLD FRONT THAT WILL BE ACCOMPANYING THIS SYSTEM WILL MOVE
THROUGH THE DISTRICT TUESDAY NIGHT/WEDNESDAY MORNING. THIS WILL USHER
IN MUCH COLDER AIR AS THE FLOW BECOMES NORTHERLY. HAVE KEPT A MENTION
OF SHOWERS ON WEDNESDAY...WITH EVEN A FEW SNOW SHOWERS IN THE HILLS
ON WEDNESDAY NIGHT.
RIDGING WILL BRING DRY WEATHER TO THE DISTRICT THURSDAY THROUGH
FRIDAY. IT COULD BE QUITE COLD THURSDAY NIGHT...DEPENDING ON THE
CLOUD COVER OR HOW MUCH WIND THERE IS.
FRIDAY NIGHT THROUGH THE NEW YEARS WEEKEND...MEDIUM RANGE MODELS ARE
IN COMPLETE DISAGREEMENT. THE GFS KEEPS A RIDGE OVER THE DISTRICT FOR
DRY WEATHER. ON THE OTHER HAND...THE ECMWF CUTS OFF AN UPPER LOW AND
PARKS IT ALONG THE CENTRAL CALIFORNIA COAST. THE GFS ENSEMBLES
GENERALLY FAVORED THE GFS SOLUTION WHEREAS THE ECMWF ENSEMBLES WERE
CLOSE TO THE ECMWF SOLUTION. THEREFORE...HAVE KEPT THE FORECAST AS IS
FOR THIS PERIOD...TOWARDS CLIMATOLOGY.
&&
.AVIATION...AS OF 9:45 PM PST MONDAY...VFR IS HOLDING SO FAR SO GOOD
TONIGHT. LOW CLOUDS AND SOME FOG WILL REDEVELOP OVERNIGHT AHEAD OF
THE NEXT WET WEATHER SYSTEM ARRIVING LATER TUESDAY.
VICINITY OF KSFO...LIGHT WINDS AND VFR. LOCAL PRESSURE GRADIENTS ARE
FLAT. MVFR CEILING AND VISIBILITY IS FORECAST BY 11Z. RAIN AND WIND
FORECAST FOR TUESDAY AFTERNOON AND NIGHT.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...LIGHT WINDS WITH HIGH CLOUDS MOVING IN.
RAIN ARRIVES LATER TUESDAY AND TUESDAY NIGHT.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
SCA...ALL WATERS TUESDAY AFTERNOON AND NIGHT
&&
$$
PUBLIC FORECAST: MHS/CW
AVIATION/MARINE: CANEPA
