Area Forecast Discussion
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FXUS61 KBOX 281219
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
719 AM EST FRI NOV 28 2014

.SYNOPSIS...
A TROUGH OF LOW PRESSURE ACROSS EASTERN NEW ENGLAND WILL RESULT
IN A PERIOD OF SNOW THIS MORNING ACROSS EASTERN MASSACHUSETTS AND
SOUTHEAST NEW HAMPSHIRE. DRY BUT COLDER WEATHER THEN OVERSPREADS
THE REGION THIS AFTERNOON AND TONIGHT. HIGH PRESSURE PROVIDES DRY
BUT CHILLY WEATHER SATURDAY. A WARM FRONT CROSSES THE AREA
SATURDAY NIGHT WITH A LIGHT WINTRY MIX OF PRECIPITATION POSSIBLE.
BEHIND THE FRONT MUCH MILDER WEATHER IS ON TAP FOR SUNDAY AND
MONDAY. A POLAR FRONT WILL THEN SWEEP ACROSS THE REGION LATER MON
BRINGING A RETURN TO COLDER WEATHER TUE. A WARM FRONT MAY THEN
BRING ANOTHER RISK OF WINTRY PRECIPITATION THE MIDDLE OF NEXT
WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

7 AM UPDATE...

NORLUN TROUGH OVER EASTERN NEW ENGLAND EXTENDING NORTHWEST FROM
OFFSHORE LOW IS CONTINUING TO GENERATE AN AREA OF SNOW FROM THE
SEACOAST OF NH SOUTHWARD THRU EASTERN MA. THIS AREA OF SNOW SHOULD
EXIT EASTERN MA BY 10 AM EXCEPT CLOSER TO MIDDAY ACROSS THE OUTER
CAPE. ALREADY 1-3 INCHES OF SNOW REPORTED ACROSS EASTERN MA WITH
HIGHEST TOTALS OVER ESSEX COUNTY AND COASTAL PLYMOUTH COUNTY. SOME
ENHANCEMENT SEEN ON LATEST RADAR LOOP ACROSS THIS REGION. THUS
ADDITIONAL SNOWFALL OF UP TO AN INCH POSSIBLE.

WILDCARD WILL BE OVER THE OUTER CAPE WHERE MODELS SUGGEST HEAVIER
QPF...WHICH MATCHES UP WITH LATEST RADAR TRENDS. HOWEVER WETBULB
TEMPS HERE ARE ABOVE FREEZING. THUS DESPITE SEEING MODERATE TO
HEAVY SNOW ON PROVINCETOWN WEB CAM SNOW WILL STRUGGLE TO
ACCUMULATE ESPECIALLY ON PAVED SURFACES. HOWEVER RADAR LOOKS
IMPRESSIVE ACROSS THIS AREA SO WILL HAVE TO MONITOR IF ADDITIONAL
COOLING TAKES PLACE VIA DYNAMICAL AND DIABATIC COOLING PROCESSES.

OTHERWISE ADDITIONAL ACCUMULATIONS SHOULD BE FOCUSED FROM THE
UPPER CAPE NORTHWARD INTO PLYMOUTH COUNTY...BOSTON TO CAPE ANN.
PREVIOUS FORECAST AND STATEMENTS /SPS AND WSW/ CAPTURES THIS
WEATHER THEME SO NO MAJOR CHANGES PLANNED. EARLIER DISCUSSION
BELOW.
-----------------------------------------------------------------
INVERTED TROUGH STARTING TO RECENTER ACROSS E MA AT 10Z WITH A
BRIEF BREAK...BUT NOTING LIGHT PRECIP FILLING IN AGAIN ACROSS E MA
INTO N RI. ANOTHER HEAVIER BATCH OF PRECIP HAS ALSO DEVELOPED
ACROSS MASS BAY AND LOOKS TO BE HEADING S TOWARD CAPE COD...WHICH
SHORT RANGE MODELS HAVE SIGNALED THIS MORNING.

SO FAR THIS MORNING...HAVE RECEIVED A FEW REPORTS INCLUDING
BETWEEN 2.5 AND 3 INCHES OF NEW SNOW IN GLOUCESTER AND 1.7 INCHES
IN MANCHESTER NH. ALSO HAVE LIGHT SNOW FALLING HERE AT KBOX AT
10Z.

EXPECT PRECIP TO CONTINUE THROUGH THE MORNING ACROSS EASTERN AREAS
AND...WITH THE CHILLY TEMPS ACROSS THE REGION...WILL SEE MORE
LIGHT SNOW EXCEPT A MIX OF LIGHT SNOW AND/OR RAIN ACROSS S
COASTAL PLYMOUTH COUNTY AND ON CAPE COD. HOWEVER...WE NOTED THAT
TEMPS WERE COOLER ON THE UPPER CAPE AROUND THE FALMOUTH AREA WHERE
LIGHT SNOW FELL OFF AND ON OVERNIGHT. WITH NEW AREA OF HEAVIER
PRECIP NOTED ON LATEST RADAR IMAGERY THAT IS TRENDING TOWARD THE
CAPE OFF MASS BAY...THIS WILL BRING STEADIER AND HEAVIER PRECIP.
THIS WILL BRING DOWN COOLER TEMPS...SO WILL SEE SOME MORE SNOW.
THIS WILL LIKELY CAUSE DYNAMIC COOLING /COLDER AIR MIXING DOWN
FROM ALOFT/ THAT WILL POSSIBLY BRING AN INCH OR TWO POSSIBLE
BEFORE ENDING EARLY THIS AFTERNOON. THIS COULD COVER THE GROUND
AND...CONSIDERING THAT THERE WILL BE QUITE A FEW TRAVELERS AND
SHOPPERS ON THE ROADWAYS TODAY...WE DECIDED TO ISSUE A WINTER
WEATHER ADVISORY CONCENTRATING THE UPPER CAPE THROUGH 3 PM. WE
ALSO INCLUDED WESTERN ESSEX...SOUTHEAST MIDDLESEX AND WESTERN
PLYMOUTH COUNTIES IN THE ADVISORY AS THERE WILL BE SOME OFF AND ON
BANDS OF STEADIER SNOW FALLING THROUGH THE MORNING THERE THAT
COULD CAUSE SNOW COVERED PRIMARY AND SECONDARY ROADS THROUGH
MIDDAY.

AS THE STRENGTHENING LOW MOVES NE WELL OFFSHORE TODAY...EXPECT
IMPROVING CONDITIONS ACROSS CENTRAL AND WESTERN AREAS THAT WILL
SHIFT E DURING THIS AFTERNOON. COLDER AIR WILL CONTINUE TO FILTER
ACROSS THE REGION. TEMPS WILL ONLY RISE TO THE UPPER 20S TO AROUND
30 ACROSS THE HIGHER TERRAIN OF S NH/N CENTRAL MA AS WELL AS THE E
SLOPES OF THE BERKSHIRES...RANGING TO THE MID 30S TO AROUND 40
ALONG THE IMMEDIATE COAST.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
TONIGHT...
ANY LEFTOVER PRECIP ON THE OUTER CAPE WILL EXIT THE COAST BY
02Z...THEN SKIES WILL BECOME MOSTLY CLEAR. W-NW WINDS WILL REMAIN
A BIT GUSTY EARLY TONIGHT ALONG THE COAST...BUT WINDS ACROSS THE
REGION WILL DIMINISH AS HIGH PRES RIDGE BUILDS E. CORE OF COLDEST
H85 TEMPS REMAINS ACROSS NORTHERN NEW ENGLAND...BUT WILL DROP TO
-10C TO -13C OVERNIGHT. WITH LIGHT WINDS...PARTLY CLOUDY SKIES AND
A NEW SNOWPACK ACROSS S NH/N CENTRAL AND W MA...WILL SEE TEMPS
FALL TO THE SINGLE DIGITS TO LOWER TEENS THERE...WHILE MID TO
UPPER TEENS WILL BE SEEN ACROSS MOST OTHER AREAS OVERNIGHT.
READINGS WILL HOLD IN THE 20S ALONG THE IMMEDIATE COAST.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
UPDATED 340 AM

HIGHLIGHTS...

* CHILLY BUT DRY SATURDAY
* MUCH MILDER SUNDAY AND MONDAY
* RETURN TO CHILLY WEATHER TUESDAY

SYNOPTIC OVERVIEW AND MODEL GUIDANCE EVALUATION...

00Z GEFS AND ECENS ENSEMBLES IN GOOD AGREEMENT ON THE LARGE SCALE
FLOW ACROSS NORTH AMERICA THIS PERIOD OFFERING A TYPICAL LATE FALL
WEATHER PATTERN...AN AMPLIFIED BUT PROGRESSIVE NORTHERN STREAM. THIS
RESULTS IN LARGE DAILY TEMPERATURE VARIATIONS ACROSS SOUTHERN NEW
ENGLAND THIS PERIOD. AS FOR THE DETERMINISTIC RUNS OF THE 00Z GFS
AND ECMWF...OTHER THAN TYPICAL TIMING /GFS FASTER WITH FROPA MON/
AND AMPLITUDE DIFFERENCES AT THIS TIME RANGE THESE MODELS ARE IN
GOOD AGREEMENT WITH THEIR ENSEMBLE COUNTERPARTS. THUS WILL USE A
MODEL BLEND AS A BASELINE FOR THIS PORTION OF THE FORECAST.

DAILY SENSIBLE WEATHER DETAILS...

SATURDAY...COLD START TO THE DAY AFTER GOOD RADIATIONAL COOLING
TONIGHT. HIGHS ONLY EXPECTED IN THE MU30S...WITH U20S AND L30S
ACROSS THE HIGHER TERRAIN. THESE TEMPS ARE 10-15 DEGS COLDER THAN
NORMAL. HOWEVER PARTLY SUNNY CONDITIONS ALONG WITH LIGHT WINDS WILL
TAKE SOME OF THE EDGE OFF THE CHILLY TEMPS.

SATURDAY NIGHT...WARM FRONT APPROACHES THE REGION. THUS INCREASING
CLOUDS WITH THE CHANCE OF SOME SPOTTY LIGHT PRECIP. MODEL SOUNDINGS
SUGGEST ANY LIGHT PRECIP WOULD BEGIN AS LIGHT SNOW OR FLURRIES THEN
TRANSITIONING TO SLEET...FREEZING RAIN BEFORE ALL RAIN. COLUMN
STRUGGLES TO SATURATE SO ANY PRECIP SHOULD LIGHT AND SPOTTY. HENCE
NOT A HIGH IMPACT EVENT.

SUNDAY AND MONDAY... SUBTROPICAL RIDGE BRIEFLY BUILDS ACROSS THE
SOUTHEAST STATES AND THIS YIELDS MILDER AIR STREAMING NORTHWARD UP
THE EASTERN SEABOARD INTO NEW ENGLAND WITH HIGHS INTO THE 50S ACROSS
RI AND EASTERN MA BOTH DAYS. POLAR COLD FRONT MAY YIELD THE RISK FOR
A FEW RAIN SHOWERS /POSSIBLE ENDING AS SNOW SHOWERS/ LATE MON/MON
NIGHT. AS MENTIONED ABOVE ECMWF SLOWER WITH FROPA THAN GFS. GIVEN
TIME RANGE WILL FOLLOW A MODEL BLEND.

TUESDAY...1042 MB HIGH AND ITS ASSOCIATED POLAR AIRMASS SETTLE OVER
NEW ENGLAND TUE WITH TEMPS NEARLY 20 DEGS COLDER THAN MON! HIGHS
ONLY IN THE 30S...MU20S HIGHER TERRAIN.

WEDNESDAY...OVERRUNNING PRECIP POSSIBLE WITH A WINTRY MIX GIVEN COLD
AIR WILL INITIALLY BE SLOW TO DISLODGE.

THURSDAY...TREND IS FOR DRIER BUT A RETURN TO COLDER WEATHER.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

.SHORT TERM /THROUGH TONIGHT/...MODERATE CONFIDENCE.

7 AM UPDATE...

MVFR AND IFR CONDITIONS IN SNOW WILL BE CONFINED TO EASTERN MA
THRU 14Z EXCEPT 18Z CAPE COD. OTHERWISE VFR CONDITIONS OVERSPREAD
ALL TERMINALS THIS MORNING AND AFTERNOON. EARLIER DISCUSSION
BELOW.

-------------------------------------------------------------

TODAY...AREA OF LIGHT SNOW...SOME WHICH MAY FALL MODERATELY AT
TIMES...ACROSS S CENTRAL NH/E MA INTO E RI. VSBYS MAY BRIEFLY
LOWER TO LIFR IN PERIODS OF MOD-HVY SNOW. WILL SEE MIXED
RAIN/SNOW ALONG COAST S OF BOSTON TO CAPE COD AND ISLANDS.
CONDITIONS SHOULD BEGIN TO IMPROVE FROM W-E AROUND 16Z-19Z AS
TROUGH MOVES OFFSHORE. FURTHER INLAND...EXPECT MAINLY VFR.

TONIGHT...MAY SEE LEFTOVER MVFR CONDITIONS ALONG E COAST WHICH
SHOULD IMPROVE BY 02Z-03Z...OTHERWISE VFR.

KBOS TERMINAL...MODERATE CONFIDENCE MAINLY FOR TIMING OF MVFR-IFR
CONDITIONS THROUGH MIDDAY...THEN WHEN IMPROVING CONDITIONS MOVE
IN. HIGH CONFIDENCE TONIGHT.

KBDL TERMINAL...HIGH CONFIDENCE.

OUTLOOK...SATURDAY THROUGH TUESDAY...MODERATE CONFIDENCE.

UPDATED 340 AM

SATURDAY...VFR. INCREASING SKY COVER SATURDAY. NORTHWEST WINDS
BECOME SOUTHWEST BUT REMAIN LIGHT.

SATURDAY NIGHT-SUNDAY...LOWERING CLOUDS SATURDAY NIGHT WITH
POTENTIAL FOR MVFR CIGS/VSBYS IN WIDELY SCATTERED PCPN LATE AT NIGHT
AND SUNDAY MORNING. LOW LEVEL WINDS...AROUND 2000 FEET...WILL
INCREASE OVERNIGHT AND SUNDAY TO 40-45 KNOTS AND MAY CREATE LOW
LEVEL WIND SHEAR.

MONDAY...VFR WITH SCATTERED SHOWERS LATE OR AT NIGHT AS A COLD FRONT
MOVES THROUGH. SOUTHWEST WINDS AHEAD OF THE COLD FRONT WILL SWITCH
TO NORTHWEST AFTER THE FRONT MOVES THROUGH.

TUESDAY...VFR WITH NORTH TO NORTHEAST WINDS.

TUESDAY...VFR WITH NORTH TO NORTHEAST WINDS.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

.SHORT TERM /THROUGH TONIGHT/...HIGH CONFIDENCE.

TODAY...N-NW WINDS WILL INCREASE DURING THE MORNING WITH GUSTS UP
TO 25 KT MAINLY ACROSS EASTERN AREAS. SEAS WILL ALSO BUILD AGAIN
UP TO 5-6 FT MAINLY OVER THE OPEN WATERS. WINDS WILL BRIEFLY GUST
TO 25 FT ACROSS CAPE COD BAY AND NANTUCKET SOUND AROUND MIDDAY SO
HAVE PUT UP SMALL CRAFT THERE. WINDS WILL BEGIN TO DIMINISH LATE
IN THE DAY.

TONIGHT...W-NW WINDS WILL DIMINISH EARLY TONIGHT BUT SEAS WILL
REMAIN AOA 5 FT ON THE OUTER WATERS AFTER MIDNIGHT BEFORE FINALLY
SUBSIDING.

OUTLOOK...SATURDAY THROUGH TUESDAY...MODERATE CONFIDENCE.

SATURDAY...HIGH PRES OVER THE WATERS EARLY THEN SLIDES OFFSHORE SAT
NIGHT. THUS FAIRLY LIGHT WINDS ALONG WITH DRY WEATHER DURING THE
DAY. RISK OF A FEW SHOWERS OF RAIN AND SNOW AT NIGHT.

SUNDAY...WARM FRONT LIFTS NORTH THRU THE REGION. MODEST SW WIND
DEVELOPS BUT MAINLY DRY WEATHER.

MONDAY...COLD FRONT REMAINS WEST OF NEW ENGLAND SO MODEST SW WINDS
CONTINUE.

TUE...COLD HIGH PRES DRIFTS ACROSS SOUTHERN QUEBEC.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ006-007-
     014>016-018-019.
     WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
     MAZ022.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ231-
     232.
     SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ250-
     256.
     SMALL CRAFT ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR ANZ251.
     SMALL CRAFT ADVISORY UNTIL 3 AM EST SATURDAY FOR ANZ254-255.

&&

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



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