FXUS61 KBOX 111003
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
503 AM EST FRI DEC 11 2009

.SYNOPSIS...
LARGE LOW PRES OVER SE CANADA WILL CONTINUE TO CIRCULATE BLUSTERY
AND UNSEASONABLY COLD WEATHER ACROSS SOUTHERN NEW ENGLAND INTO
SAT. A WEAK WAVE OF LOW PRES WILL MOVE S OF SOUTHERN NEW ENGLAND
SUN AFTERNOON AND EVENING...BRINGING A PERIOD OF RAIN AND OR SNOW TO
THE REGION. WEAK HIGH PRES FOLLOWS MON PROVIDING DRY AND SEASONABLE
TEMPS. ANOTHER COLD FRONT SHOULD MOVE ACROSS THE REGION LATE TUE
BRINGING MUCH COLDER AIR TO THE REGION WED AND THU.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SNOW SHOWER ACTIVITY FROM THE GREAT LAKES HAS WEAKENED AND SHIFTED
INTO SOUTHEAST MA AS OF 3 AM. STRONG COLD AIR ADVECTION /-16C AT 850
MB/ WILL CONTINUE TO BE DELIVERED ON WESTERLY FLOW ACROSS THE
NORTHEAST. THIS WILL BE A FAVORABLE WIND TRAJECTORY FOR LAKE EFFECT
PLUMES TO SPILL OVER THE BERKSHIRES AND INTO SOUTHERN NEW ENGLAND.
HOWEVER...MODELS HAVE BEEN STRUGGLING WITH THESE MESOSCALE BANDS
EARLY THIS MORNING SO THE TIMING AND LOCATION OF ANY SNOW SHOWER
ACTIVITY WILL BE DIFFICULT AT BEST.

ALL MODEL GUIDANCE SUGGEST MID LEVEL SHORT WAVE ENERGY /ALBEIT WEAK-
SUBTLE/ TO MOVE ACROSS THE AREA TODAY...WITH BULK OF JET ENERGY
ACROSS NORTHERN AREAS /MA PIKE NORTHWARD/. THEREFORE WEAK SYNOPTIC
SCALE LIFT SHOULD COMBINE WITH LEFTOVER LAKE EFFECT MOISTURE PLUME
TO YIELD SCATTERED SNOW SHOWERS TODAY...ESPECIALLY THIS AFTERNOON AS
LOW LEVEL LAPSE RATES STEEPEN.  NOT EXPECTING MUCH IF ANY
ACCUMULATION GIVEN LIMITED DURATION OF SNOW SHOWER ACTIVITY.

AS FOR TEMPS...SIDED WITH THE COOLER METNAM GUIDANCE GIVEN MAGNITUDE
OF COLD AIR ALOFT. MOST LOCATIONS WILL REMAIN IN THE 20S TODAY /LOW
30S COASTAL PLAIN/ WITH BLUSTERY WEST WINDS YIELDING WIND CHILLS IN
THE SINGLE DIGITS THIS MORNING AND TEENS THIS AFTERNOON. HIGHS TODAY
WILL AVERAGE ABOUT 10 DEGS BELOW NORMAL. 

REGARDING WINDS...TIGHT PRES GRADIENT WILL COMBINE WITH STRONG COLD
AIR ADVECTION TO YIELD WIND GUSTS OF 40-45 MPH. ALL MODEL GUIDANCE
INCLUDING BUFKIT SOUNDINGS AND 03Z SREF WIND PROBS SUGGEST WIND GUSTS
JUST UNDER WIND ADVISORY CRITERIA TODAY. THEREFORE WILL HOLD OFF ON A
WIND ADVISORY. HIGHEST PROB OF GUSTS EXCEEDING 45 MPH TODAY WILL BE
OVER THE CAPE AND ISLANDS ALONG WITH THE HIGHER TERRAIN. AGAIN...THIS
IS A LOW PROB.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
TONIGHT...

MORE OF THE SAME - COLD WESTERLY FLOW INTO NEW ENGLAND. COULD HAVE
SOME LAKE EFFECT SNOW SHOWERS SPILL INTO NORTHERN MA AND NEARBY
SOUTHWEST NH. STRONG WIND GUSTS CONTINUE WITH SPEEDS UP TO 40-45 MPH. 
AS FOR TEMPS...BLENDED THE COLDER METNAM WITH THE WARMER GFS MOS.

SATURDAY...

COLD WEATHER BEGINS TO EASE LATER IN THE DAY AS 850 TEMPS GO FROM
-16C TO ABOUT -10C. WINDS ABATE LATER IN THE DAY AS HIGH PRES BUILDS
IN FROM THE MID ATLC. NEVERTHELESS...ANOTHER CHILLY DAY BUT NOT QUIET
AS COLD AS TODAY.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
SATURDAY NIGHT...A COLD AND DRY NIGHT ON TAP ACROSS THE REGION.

SUNDAY....WILL SEE SOME MODERATION IN TEMPERATURES SUNDAY AS HIGH 
PRESSURE SLIPS EAST OF THE AREA AND WINDS SHIFT TO THE SOUTH. A 
WARM FRONT AND WEAK INVERTED TROUGH WILL APPROACH THE AREA FROM THE 
SOUTHWEST DURING THE AFTERNOON. NOTING INCREASING WARM AIR ADVECTION
AND THE DEVELOPMENT OF A SOUTHERLY LOW LEVEL JET ACROSS THE WESTERN
ZONES DURING THE AFTERNOON HOURS. THIS OCCURS AS A WAVE OF LOW 
PRESSURE FORMS ALONG THE MID ATLANTIC COAST BY EVENING. SOME
TIMING ISSUES EXIST BETWEEN THE SLOWER NAM/RGEM AND MORE 
PROGRESSIVE GFS/ECMWF BUT THE DIFFERENCES ARE FAIRLY MINOR.

OVERALL HAVE INCREASED POPS SUNDAY AFTERNOON TO LIKELY ACROSS THE 
CENTRAL AND WEST...CHANCE POPS FURTHER EAST. THE COMBINATION OF 
SUBZERO H85 TEMPS GENERALLY NORTH OF THE CT/RI BORDER AND INCREASING 
ISENTROPIC LIFT...SHOULD ALLOW FOR A FEW HOURS OF SNOW TO BEGIN THIS 
EVENT ACROSS THE INTERIOR. ALONG THE COAST BOUNDARY LAYER TEMPS WILL 
BE TOO WARM AND THIS WILL FAVOR ALL RAIN. 

SUNDAY NIGHT...INCREASING WARM AIR ADVECTION EXPECTED AS THE 
INVERTED TROUGH STRENGTHENS. THE GFS FEATURES A DEEPENING UPPER 
LEVEL TROUGH AND SURFACE LOW TO THE SOUTH OF LONG ISLAND DURING
THE EVENING WHILE THE NAM/ECMWF AND RGEM TAKE A FEW HOURS LONGER.

GOOD MODEL CONSENSUS SO HAVE BOOSTED POPS TO CATEGORICAL ACROSS 
MUCH OF THE AREA WITH LIKELY POPS NORTH. PRECIPITATION SHOULD CHANGE 
TO RAIN ACROSS MUCH OF THE AREA EXCEPT PERHAPS THE FAR INTERIOR 
NORTHWEST WHERE THERMAL PROFILES ARE A BIT MORE MARGINAL. THERE
COULD BE AN ADVISORY LEVEL SNOWFALL ACROSS INTERIOR NORTHWEST 
MASSACHUSETTS AND SOUTHWESTERN NH BEFORE PRECIPITATION TAPERS OFF
BY DAYBREAK. CURRENTLY BEST OMEGA APPEARS TO BE BELOW THE DENDRITIC 
SNOW GROWTH REGION. POPULATED SLIGHTLY COLDER NAM THICKNESSES AND 
GFS QPF AMOUNTS TO DERIVE SNOWFALL TOTALS.

MONDAY THROUGH TUESDAY...MONDAY SHOULD FEATURE DRY CONDITIONS AS
THE FORECAST AREA WILL BE SITUATED INBETWEEN WEATHER SYSTEMS. HAVE 
CHANCE POPS MENTIONED FOR TUESDAY AND TUESDAY NIGHT AS A COLD FRONT 
CROSSES THE AREA. GENERALLY FOLLOWED THE GFS/CANADIAN GGEM SOLUTIONS.

WEDNESDAY THROUGH THURSDAY...ARCTIC AIR SPREADS ACROSS THE REGION.
USED A BLEND OF RAW 2M AND MOSGUIDE TEMPERATURES FOR HIGHS AND 
FOLLOWED MOSGUIDE FOR LOWS. DRY CONDITIONS EXPECTED TO PREVAIL WITH 
THE EXCEPTION OF PERHAPS A FEW SCATTERED SNOW SHOWERS AND FLURRIES
ACROSS THE INTERIOR HIGH TERRAIN AS LAKE MOISTURE ADVECTS DOWNWIND.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
TODAY...
VFR WITH BKN CIGS040-050 AT TIMES. SCATTERED SNOW SHOWERS FROM BOS-
ORH-ALB AND POINTS NORTHWARD MAY LOWER VSBY BRIEFLY TO 2SM ALONG
WITH CIGS025. HOWEVER THE BULK OF THE DAY WILL BE VFR. STRONG WEST
WINDS WILL FREQUENTLY GUSTS UP TO 35 KT ALL TERMINALS. 

TONIGHT...

VFR WITH FREQUENT GUSTS 30-35 KT FROM THE WEST.

SATURDAY...
VFR WITH WEST WINDS NOT AS ROBUST WITH GUSTS UP TO 25 KT. 

OUTLOOK /SATURDAY NIGHT THROUGH TUESDAY/...
SATURDAY NIGHT...VFR.

SUNDAY...VFR TO START THEN MVFR IN -RA SOUTHWEST/-SN NORTHWEST AS AN
INVERTED TROUGH APPROACHES THE AREA IN THE AFTERNOON.

SUNDAY NIGHT...MVFR CEILNGS/VSBYS IN -RA WITH -SN WELL NORTHWEST AS
AN INVERTED TROUGH CROSSES THE AREA.

MONDAY...VFR BUT PERHAPS MVFR CEILINGS EARLY ACROSS THE CAPE AND 
ISLANDS.

TUESDAY...MVFR IN SCT -SHRA/-SHSN AS A COLD FRONT APPROACHES.

&&

.MARINE...
TODAY AND TONIGHT...

WESTERLY GALES CONTINUE ALONG WITH SCATTERED SNOW SHOWERS OFFSHORE
WITH COLD AIR OVERRUNNING RELATIVELY WARM OCEAN. RESIDUAL SOUTH
SWELLS FROM WEDNESDAY/S STORM WILL COMBINE WITH LARGE WEST WIND WAVES
TO YIELD HAZARDOUS SEA CONDITIONS.

SATURDAY...

WINDS BEGIN TO EAST A BIT LATER IN THE DAY AND BECOME SUB-GALE.

OUTLOOK /SATURDAY NIGHT THROUGH TUESDAY/...
SATURDAY NIGHT...A LEFTOVER SMALL CRAFT ADVISORY DURING THE EVENING
FOR WNW WIND GUSTS TO 25 TO 30 KT AND SEAS UP TO 6 FEET. WINDS AND
SEAS DIMINISH OVERNIGHT AS HIGH PRES BRIEFLY BUILDS.
 
SUNDAY...WINDS AND SEAS EXPECTED TO BE BELOW SCA CRITERIA. S WINDS 
COULD GUST UP TO 20 KT ALONG THE S COAST DURING THE AFTERNOON

SUNDAY NIGHT...COASTAL LOW PRESSURE DEVELOPING OFF THE MID ATLANTIC 
COAST WILL CAUSE SHIFTING WINDS TO E THEN N OVERNIGHT. SEAS MAY 
BUILD UP TO 5 FEET ACROSS THE OUTER WATERS. 

MONDAY...A SMALL CRAFT ADVISORY POSSIBLE FOR N WINDS GUSTING UP TO 
25 KT ACROSS THE OUTER WATERS AND SEAS UP TO 6 FT.

TUESDAY...A SMALL CRAFT ADVISORY MAY BE NEEDED. SHIFTING WINDS TO 
SOUTHWEST AHEAD OF A COLD FRONT. WINDS COULD GUST TO 20 TO 25 KT AND 
SEAS MAY BUILD UP TO 5 FEET LATE.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...GALE WARNING UNTIL 2 PM EST SATURDAY FOR ANZ232.
     GALE WARNING UNTIL 10 AM EST SATURDAY FOR ANZ231-233>235-256.
     GALE WARNING UNTIL 5 PM EST SATURDAY FOR ANZ230-250-251-254-
     255.
     GALE WARNING UNTIL 5 AM EST SATURDAY FOR ANZ236-237.

&&

$$
SYNOPSIS...NOCERA/STRAUSS
NEAR TERM...NOCERA
SHORT TERM...NOCERA
LONG TERM...STRAUSS
AVIATION...NOCERA/STRAUSS
MARINE...NOCERA/STRAUSS