Area Forecast Discussion
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467
FXUS61 KBOX 061759
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1259 PM EST SAT FEB 6 2016

.SYNOPSIS...
HIGH PRESSURE BRINGS DRY WEATHER THIS WEEKEND WITH ABOVE NORMAL
TEMPERATURES BY SUNDAY. TWO DEVELOPING COASTAL STORMS MAY BRING
ACCUMULATING SNOW MONDAY ESPECIALLY ACROSS EASTERN MA...THEN TUE
AND WED FOR THE REMAINDER OF THE REGION. AN ARCTIC COLD FRONT
BRINGS MUCH CHILLIER AIR FOR THE END OF THE WEEK.

&&

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

1 PM UPDATE...

NO MAJOR CHANGES TO PREVIOUS FORECAST. TEMPS CLIMBING JUST ABOVE
FREEZING IN MANY LOCATIONS AS OF 1230 PM. SUNSHINE AND LIGHT WINDS
ALSO CONTRIBUTING TO PLEASANT CONDITIONS BY EARLY FEB STANDARDS.

PREVIOUS DISCUSSION...

WEAK UPPER LEVEL TROUGH BEGINS TO SET UP OVER THE REGION
TODAY. A PASSING HIGH TO OUR SOUTH WILL TIGHTEN THE PRESSURE GRADIENT
ACROSS THE REGION FOR THIS AFTERNOON. ANTICIPATE GUSTS BETWEEN 15-20
MPH. WEAK SHORTWAVE WILL WILL ALSO BRING SOME MID-LEVEL MOISTURE
INTO THE AREA RESULTING IN A FILTERED SUNSHINE. GUIDANCE DOES
INDICATE TEMPERATURES IN THE UPPER 30S TO LOW 40S BUT WITH THE FRESH
SNOW PACK THAT MAY BE A BIT TO OPTIMISTIC.

&&

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

HIGH PRESSURE WILL MAINLY DOMINATE RESULTING IN QUIET WEATHER.
HOWEVER PRESSURE GRADIENT WILL BE SLOW TO RELAX WHICH WILL LIMIT
RADIATIONAL COOLING OVERNIGHT. TEMPS WILL DROP INTO THE 20S WITH
PERHAPS LOW READINGS IN AREAS WHERE THE WIND WILL BE CALM.

SUNDAY...

LOW PRESSURE SYSTEM TO THE NORTH WILL DRAG A WEAK COLD FRONT THROUGH
THE REGION ON SUNDAY. THIS FRONT WILL BE DRY BUT MAY BRING IN SOME
CLOUDS. WESTERLY FLOW WILL DOMINATE IN THE AFTERNOON WHICH WILL
ALLOW FOR TEMPERATURES TO WARM IN TO THE 40S. HELP AID IN MELTING
SOME OF THE SNOW.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BIG PICTURE...

LONGWAVE PATTERN SHOWS RIDGE WEST/TROUGH EAST AS BEFORE...WITH
INCREASING AMPLITUDE EARLY WEEK AND DECREASING AMPLITUDE LATE WEEK.
OVERALL A COLD AND UNSETTLED PATTERN FOR SOUTHERN NEW ENGLAND.  AT
SHORTER WAVE SCALES WE SEE THREE SHORTWAVES AFFECTING THE PATTERN.
THE FIRST IS IN THE LOWER MISS RIVER VALLEY AND GENERATES COASTAL
LOW PRESSURE OFF THE CAROLINAS SUNDAY. THIS SWINGS WIDE OF OUR
AREA...CROSSING ABOUT 4 DEGREES SOUTH OF THE 40N/70W BENCHMARK...AND
THEN SWEEPS NORTHEAST JUST SOUTH OF NOVA SCOTIA. THE SECOND
SHORTWAVE IS MOVING ASHORE IN THE PACIFIC NORTHWEST AND WILL CARVE A
DEEP COLD TROUGH OVER THE EASTERN USA DURING THE EARLY WEEK.  THE
THIRD SHORTWAVE IS ALONG THE ARCTIC OCEAN COASTLINE AND WILL DROP
SOUTH INTO THE USA MIDWEEK.

OPERATIONAL GUIDANCE MASS FIELDS ARE SIMILAR ON THE BROAD SCALE MOST
OF THE PERIOD. BUT THERE ARE DIFFERENCES IN THE DETAILS...ESPECIALLY
REGARDING THE SECOND SHORTWAVE AND ITS DEVELOPING COASTAL SYSTEM
TUESDAY. THIS SECOND SHORTWAVE WAS JUST COMING ASHORE AT MEASUREMENT
TIME LAST NIGHT. THE 12Z SATURDAY MODELS SHOULD HAVE A BETTER READ
ON THE SHORTWAVE AND ITS EFFECTS. WE CONTINUE TO FAVOR A MODEL BLEND
ESPECIALLY USING THE GFS AND ECMWF.

THE DAILIES...

SUNDAY NIGHT-MONDAY... COASTAL STORM PASSES WELL OFFSHORE...SOME 4
DEGREES SOUTH OF THE BENCHMARK. NORMALLY THAT WOULD MEAN A SWING AND
A MISS FOR STRIKE THREE. BUT HIGH PRESSURE BUILDS SOUTH FROM QUEBEC
AND ESTABLISHES A PRESSURE GRADIENT THAT SHOULD BRING A NORTHEAST
MARINE FLOW WITH DELTA OF 13-15C. THIS SHOULD AT LEAST BRING
INCREASING CLOUDS OVERNIGHT AND MONDAY. LESS CONFIDENCE ON PCPN
GIVEN MEDIOCRE FORCING AND CHANGING RUN-TO-RUN AMOUNTS.

MODELS HAVE BACKED OFF ON QPF DURING MONDAY WITH MAIN FOCUS ON CAPE
AND ISLANDS...POSSIBLY EASTERN MASS. WE HAVE BACKED OFF ONSET OF
POPS UNTIL 06-12Z MONDAY AND VALUE OF POPS BY ABOUT 20 PERCENT. THIS
STILL BRINGS POTENTIAL FOR SEVERAL INCHES IN EASTERN MASS WITH
HIGHEST AMOUNTS CAPE COD/PLYMOUTH CO AREA.

MONDAY NIGHT-TUESDAY... SECOND SHORTWAVE DIGS OVER THE MIDWEST WITH
SURFACE LOW REDEVELOPMENT ALONG THE MID ATLANTIC COAST. THIS NEW
COASTAL LOW THEN MOVES PAST NEW ENGLAND. BETTER DYNAMICS AND
RESULTING LIFT SHOULD BE IN PLACE AND WITH DEEPER MOISTURE WOULD
EXPECT THIS TO BE A BETTER CHANCE OF PCPN THAN THE MONDAY OFFSHORE
SYSTEM. BUT THE RESPONSIBLE SHORTWAVE IS JUST NOW MOVING ASHORE AS
NOTED ABOVE. SO STILL SOME UNCERTAINTY WITH THIS SYSTEM AND ITS
POTENTIAL. WE WILL BRING A PERIOD OF LIKELY POPS AS THE SYSTEM MOVES
THROUGH.

WEDNESDAY THROUGH FRIDAY... UPPER TROUGH WITH ITS COLD POOL ALOFT
AND CLOUD SHIELD LINGER WEDNESDAY. THE ARCTIC SHORTWAVE THEN SWINGS
THROUGH ON THURSDAY. EXPECT QUITE A FEW CLOUDS DURING THIS PERIOD
WITH A CHANCE OF SNOW SHOWERS. CLIPPER LOW THEN DROPS SOUTHEAST FROM
NORTHERN ONTARIO FRIDAY AND BRINGING MORE CLOUDS AND SCATTERED SNOW
SHOWERS. MIXED LAYER REACHES EITHER SIDE OF 925 MB EACH DAY...A
LITTLE HIGHER THURSDAY BEHIND THE ARCTIC SHORTWAVE AND SURFACE
FRONT. TEMPS ALOFT AT THE TOP OF THE LAYER SUPPORT 30S
WEDNESDAY...20S WEST/32 EAST THURSDAY...AND 20S TO NEAR 30 FRIDAY.
AS NOTED EARLIER...COLD AND UNSETTLED.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH SUNDAY/...

1 PM UPDATE ...

THRU TONIGHT ... HIGH FORECAST CONFIDENCE FOR VFR/DRY AND LIGHT
SW WIND. WINDS MAY GUSTS UP TO 15-20 KT CAPE COD AND ISLANDS THIS
EVENING.

SUNDAY ... HIGH CONFIDENCE FOR VFR. LIGHT AND VARIABLE WINDS
BECOMING NE TOWARD SUNSET.

SUNDAY NIGHT ... VFR AND DRY THRU ABOUT MIDNIGHT. THEN LOWERING TO
MVFR WITH INCREASING CHANCES OF SNOW OR MIX RAIN/SNOW TOWARD
DAYBREAK MON. NE WINDS GUSTING UP TO 35 KT CAPE COD AND ISLANDS
TOWARD 12Z MON.

KBOS TERMINAL...HIGH CONFIDENCE THRU SUN EVENING THEN LOWERING
LATE SUN NIGHT REGARDING ARRIVAL OF LOWER CIGS/VSBYS IN SNOW/RAIN.

KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS.

OUTLOOK /MON THROUGH WEDNESDAY/...

TWO POTENTIAL STORMS DURING THIS PERIOD...EITHER COULD BRING
IFR/LIFR CIGS AND VSBYS IN SNOW. THE FIRST CHANCE FOR THIS WILL BE
MONDAY...WITH BEST CHANCE ON CAPE COD AND ISLANDS. NORTH-NORTHEAST
WINDS WILL GUST TO 35 KNOTS ALONG THE EASTERN MASS COAST. THE SECOND
CHANCE WILL BE MONDAY NIGHT AND TUESDAY WITH ALL OF SOUTHERN NEW
ENGLAND UNDER THE GUN. CONDITIONS IMPROVE WEDNESDAY TO MVFR CIGS
WITH SCATTERED SNOW SHOWERS.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH SUNDAY/...HIGH CONFIDENCE.

1 PM UPDATE ... NO MAJOR CHANGES FROM PREVIOUS FORECAST. CHOP
SEAS DEVELOP THIS AFTERNOON AS WSW WINDS OPPOSE EASTERLY SWELLS
ACROSS THE OCEAN WATERS OF RI AND MA. EARLIER DISCUSSION BELOW.

======================================================================

LINGERING SWELLS AND SEAS WILL BEGIN TO SUBSIDE TODAY. SCA LINGERS FOR
A PORTION OF THE DAY...BUT MAY BE ABLE TO BE DROPPED SOONER.

HIGH PRESSURE WILL BUILD OVER THE WATERS THROUGH THE WEEKEND. AN
INCREASE IN THE GRADIENT WILL ALLOW FOR SOME GUSTY WINDS ACROSS THE
NORTHERN WATERS LATE THIS AFTERNOON INTO TONIGHT. SEAS WILL BUILD IN
RESPONSE. SCA MAY BE NEEDED TONIGHT AND INTO TOMORROW FOR BUILDING
SEAS IN RESPONSE TO GUSTY WINDS.

OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/...MODERATE CONFIDENCE...

SUNDAY NIGHT-MONDAY...A DEVELOPING GALE CENTER WILL PASS WELL
OFFSHORE SOUTHEAST OF NANTUCKET...BUT STRONG WINDS WILL EXTEND AN
UNUSUAL DISTANCE OUT FROM THE WEATHER SYSTEM. NORTHEAST WINDS OVER
THE WATERS WILL INCREASE TO GALE FORCE. THIS WILL BUILD SEAS OF 7 TO
11 FEET ON THE EXPOSED WATERS. A GALE WARNING WILL EVENTUALLY BE
NEEDED FOR LATE SUNDAY NIGHT AND MONDAY. ALSO EXPECT REDUCED VSBYS
IN RAIN AND SNOW.

MONDAY NIGHT-TUESDAY...A SECOND WEATHER SYSTEM WILL DEVELOP ALONG
THE MID ATLANTIC COAST AND MOVE OUTSIDE NANTUCKET. THIS WILL BRING
ANOTHER PERIOD OF NORTHEAST WINDS WITH GUSTS OVER 25 KNOTS. THERE
REMAIN MANY QUESTIONS ABOUT THIS NEXT SYSTEM...AS WELL AS LOW
POTENTIAL FOR WINDS REACHING 35 KNOTS. SEAS WILL REMAIN AT 7 TO 11
FEET.

WEDNESDAY... WINDS DIMINISH AS THE SECOND COASTAL STORM MOVES OFF.
WIND SPEEDS SHOULD GO BELOW 25 KNOTS. ROUGH SEAS WILL LINGER MUCH OF
THE DAY ESPECIALLY ON THE SOUTHERN EXPOSED WATERS.

&&

.TIDES/COASTAL FLOODING...
MONDAY...

THERE IS A FAIRLY HIGH ASTRO TIDE OF 11.2 IN BOSTON LATE MONDAY
MORNING.  NORTHEAST WIND GUSTS OF 30 TO 40 KNOTS FROM LARGE
CIRCULATION OF THE INTENSIFYING OCEAN STORM WILL LIKELY RESULT IN A
1 TO 1.5 SURGE.  SEAS SHOULD BE BUILT UP TO BETWEEN 10 AND 15 FEET
BY THEN...SO FEEL THERE IS A DECENT SHOT FOR POCKETS OF MINOR
COASTAL FLOODING ALONG EASTERN MA COAST.  THERE IS A LOW RISK FOR
POCKETS OF MODERATE COASTAL FLOODING...IF THE STORMS ENDS UP A BIT
FASTER AND TRACKING FURTHER WEST THAN CURRENT GUIDANCE INDICATES.

MONDAY NIGHT AND TUESDAY...

MAIN CONCERN IS IF WE END UP WITH A SECOND AREA OF STRONG LOW
PRESSURE TRACKING UP THE COAST...WHICH COULD IMPACT ADDITIONAL HIGH
TIDE CYCLES. LARGE SPREAD IN THE GUIDANCE ON WHETHER OR NOT THIS
HAPPENS.  IF SO...WILL HAVE TO WATCH THE TUESDAY NOON HIGH TIDE
CYCLE ACROSS EASTERN MA AS BOSTON HAS AN 11.5 ASTRO TIDE.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ250.
     SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ254-
     255.

&&

$$
SYNOPSIS...WTB/DUNTEN
NEAR TERM...NOCERA
SHORT TERM...DUNTEN
LONG TERM...WTB
AVIATION...WTB/NOCERA
MARINE...WTB/NOCERA/DUNTEN
TIDES/COASTAL FLOODING...



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