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Area Forecast Discussion
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000
FXUS61 KBOX 122244
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
643 PM EDT THU MAR 12 2015

.SYNOPSIS...
DRY BUT CHILLY WEATHER THROUGH FRIDAY NIGHT. LOW 
PRESSURE WILL BRING A COLD SOAKING RAIN ON SATURDAY...PROBABLY 
STARTING AS A BRIEF PERIOD OF FREEZING RAIN FOR SOME EARLY SATURDAY 
MORNING.  LEFT OVER RAIN SHOWERS WILL CHANGE TO SCATTERED SNOW 
SHOWERS LATE SATURDAY NIGHT INTO SUNDAY. DRY WEATHER RETURNS MONDAY 
FOLLOWED BY A BRIEF PERIOD OF MAINLY RAIN MONDAY NIGHT INTO EARLY 
TUESDAY. A SHOT OF UNSEASONABLY COLD WEATHER WILL FOLLOW LATE 
TUESDAY INTO WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...

640 PM UPDATE...

HIGH PRESSURE CRESTS OVER OUR REGION. THIS WILL MEAN
DIMINISHING WINDS WITH MOSTLY CLEAR SKIES AND A GOOD NIGHT OF 
RADIATIONAL COOLING. THERE ARE SOME MID AND HIGH CLOUDS JUST NORTH 
OF THE GREAT LAKES THIS AFTERNOON. SOME OF THESE WILL MOVE INTO OUR 
REGION TOWARD DAYBREAK...BUT PROBABLY NOT HAVE A BIG IMPACT ON 
OVERNIGHT LOW TEMPS.  GIVEN DRY AIRMASS AND STILL A DECENT SNOW 
PACK...LOW TEMPS MAY BOTTOM OUT IN THE HIGH SINGLE DIGITS TO THE 
LOWER TEENS ACROSS THE NORMALLY COLDEST OUTLYING LOCATIONS.  THE 
REST OF THE REGION SHOULD SEE LOWS IN THE TEENS TO AROUND 20.  

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
HIGH PRESSURE WILL MOVE EAST OF OUR REGION. THIS WILL ALLOW FOR A
RETURN SOUTHWEST FLOW AND MODEST WARM ADVECTION THROUGH THE DAY.
THE SUBSIDENCE ALOFT REMAINS IN CONTROL...SO DRY WEATHER WITH
PARTIAL CLOUDINESS IS EXPECTED. MAX TEMPERATURES WILL MODERATE
SOMEWHAT IN COMPARISON TO THURSDAY...BUT SUSPECT THAT MOST PLACES
REMAIN NEAR TO JUST BELOW NORMAL VALUES.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...

HIGHLIGHTS...

* COLD RAIN SATURDAY BUT A PERIOD OF FREEZING RAIN LIKELY AT ONSET
* LIGHT ICING POTENTIAL SAT AM MAY BE HIGH IMPACT FOR MOTORISTS
* RAIN CHANGES TO SCT SNOW SHOWERS LATE SAT NIGHT/SUN WITH A LOW 
  RISK FOR A LIGHT ACCUMULATION
* A PERIOD OF MAINLY RAIN SHOWERS MON NIGHT INTO EARLY TUE
* SHOT OF UNSEASONABLY COLD AIR LATE TUE INTO WED

DETAILS...

FRIDAY NIGHT AND SATURDAY...

LOW PRESSURE WILL BE APPROACHING FROM THE SOUTHWEST AS HIGH PRESSURE 
SLOWLY MOVES OFF THE COAST.  FRI NIGHT SHOULD BE DRY...BUT EXPECT 
SOME PRECIPITATION TO DEVELOP SOMETIME TOWARD DAYBREAK INTO EARLY 
SAT MORNING.  MODEL SOUNDINGS SHOW A FAIRLY PRONOUNCED WARM LAYER 
FROM AROUND 950 MB TO 850 MB INTRUDING AHEAD OF THE MAIN 
PRECIPITATION SHIELD.  SNOW POTENTIAL IS VERY LIMITED ON THE FRONT 
END OF THIS SYSTEM...BUT THERE IS A LOW PROBABILITY OF A LITTLE BIT 
ACROSS EXTREME NORTHERN MA.  WE ARE MORE CONCERNED ABOUT A PERIOD OF 
LIGHT FREEZING RAIN.  MODELS ARE OFTEN TOO FAST IN ERODING BOUNDARY 
LAYER COLD WHEN SURFACE WINDS ARE RATHER LIGHT.  IN FACT...EVEN THE 
13 KM ECMWF/RGEM/NAM HAVE SURFACE TEMPS NEAR OR JUST BELOW FREEZING 
ACROSS A GOOD CHUNK OF THE REGION AT 12Z SATURDAY.  WHILE COLDEST 
AIR IS NORTH OF MA TURNPIKE...PRECIP ARRIVES EARLIER IN NORTHERN CT 
SO MUCH OF THE AREA IS AT RISK.  WHILE ANY ICING SHOULD BE QUITE 
LIGHT...GIVEN THAT PRECIP MAY BEGIN AS STRAIGHT FREEZING RAIN IS 
CONCERNING.  THESE VERY LIGHT ICING EVENTS OFTEN CATCH PEOPLE OFF 
GUARD AND RESULT IN NUMEROUS ACCIDENTS.  WE WILL LIKELY NEED 
FREEZING RAIN ADVISORIES FOR AT LEAST A PORTION OF THE REGION.

GIVEN HIGH MOVING AWAY FROM THE REGION...SHOULD SEE PTYPE CHANGE TO 
ALL RAIN SAT AFTERNOON.  RAINFALL AMOUNTS OF 0.50 TO 1.00 INCH SEEM 
REASONABLE AT THIS TIME.  IT WILL BE A COLD RAIN...SO NOT ENOUGH TO 
RELEASE A LOT OF WATER FROM THE SNOW PACK AND RIVER/STREAM FLOODING 
IS NOT A CONCERN.  HOWEVER...TYPICAL NUISANCE POOR DRAINAGE STREET 
FLOODING IS POSSIBLE.

SATURDAY NIGHT AND SUNDAY...

FORECAST CONFIDENCE REMAINS LOW.  FIRST WAVE OF LOW PRESSURE EXITS 
THE REGION.  HOWEVER...POTENT NORTHERN STREAM ENERGY DIVES SOUTH AND 
CLOSES OFF SOMEWHERE IN THE VICINITY OF SOUTHERN NEW ENGLAND.  WHERE 
EXACTLY THIS OCCURS WILL HAVE A HUGE IMPACT ON OUR WEATHER.  

1) MOST LIKELY SCENARIO: 

MOST OF THE 12Z GUIDANCE HAS THE UPPER LEVEL LOW CLOSING OFF ON TOP 
OF US OR TO OUR NORTH.  THIS WOULD RESULT IN JUST SCATTERED RAIN 
SHOWERS CHANGING TO SCATTERED SNOW SHOWERS.  PERHAPS A VERY SMALL 
SLUSHY ACCUMULATION WOULD OCCUR ON GRASSY SURFACES...BUT OF LITTLE 
IMPACT.

2) LOWER PROBABILITY SCENARIO:
 
GIVEN WE ARE STILL 3+ DAYS OUT WILL HAVE TO WATCH THAT THE UPPER 
LEVEL LOW DOES NOT CLOSE OFF A BIT FURTHER SOUTH THEN MODELS DEPICT. 
WHILE THIS IS MUCH LOWER PROBABILITY...UPPER LEVEL ENERGY IS FAIRLY 
ROBUST.  IF THAT WERE TO OCCUR RAIN WOULD CHANGE TO SEVERAL INCHES 
OF ACCUMULATING SNOW. AGAIN...A LOW PROBABILITY AT THIS POINT BUT 
SOMETHING WE CAN NOT COMPLETELY RULE OUT YET.

MONDAY THROUGH THURSDAY...

DRY DURING THE DAY MONDAY...BUT A FAST MOVING PIECE OF NORTHERN 
STREAM ENERGY WILL LIKELY BRING A ROUND OF PRECIPITATION MON NIGHT 
INTO EARLY TUE.  LOOKS LIKE MAINLY A PERIOD OF RAIN SHOWERS WITH 
WARM ADVECTION AHEAD OF THE SHORTWAVE.  THERE IS A LOW RISK THAT 
SOME AREAS COULD END AS A BIT OF SNOW...BUT A SECONDARY LOW WOULD 
HAVE TO DEVELOP CLOSE ENOUGH TO THE COAST.  OTHERWISE...A SHOT OF 
UNSEASONABLY COLD AIR MOVES IN TUE NIGHT INTO WED.  HIGHS WED 
PROBABLY STAY IN THE 30S.  TEMPS PROBABLY MODERATE SOME ON THU.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH THURSDAY NIGHT/...HIGH CONFIDENCE.

TONIGHT INTO FRIDAY...VFR.  GUSTY WINDS DIMINISH EARLY THIS EVENING.
 
KBOS TAF...HIGH FORECAST CONFIDENCE.

KBDL TAF...HIGH FORECAST CONFIDENCE.

OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...

FRIDAY NIGHT THROUGH SATURDAY...MODERATE CONFIDENCE.  MVFR-IFR 
CONDITIONS EXPECTED TO DEVELOP TOWARD DAYBREAK SAT AND THROUGH SAT 
AFTERNOON.  MAINLY LOOKING AT A COLD RAIN...BUT A PERIOD OF FREEZING 
RAIN APPEARS LIKELY FOR AT LEAST PORTION OF THE REGION AT THE ONSET.

SATURDAY NIGHT AND SUNDAY...MODERATE CONFIDENCE.  SOME MVFR 
CONDITIONS WILL REMAIN POSSIBLE IN SCATTERED RAIN CHANGING TO SNOW 
SHOWERS. 

MONDAY AND TUESDAY...MODERATE CONFIDENCE.  MAINLY VFR BUT A PERIOD 
OF MVFR-IFR CONDITIONS WILL PROBABLY OCCUR IN SOME RAIN SHOWERS 
MONDAY NIGHT INTO EARLY TUESDAY.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT-TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.

GUSTY NORTHWEST WINDS WILL DIMINISH THIS EVENING INTO THE
OVERNIGHT HOURS AND SEAS WILL GRADUALLY LOWER.  HOWEVER...SMALL 
CRAFT SEAS FROM LEFT OVER SWELL WILL CONTINUE ACROSS THE EASTERN 
WATERS THROUGH DAYBREAK.

THESE SMALL CRAFT SEAS ACROSS THE EASTERN COASTAL WATERS WILL 
GRADUALLY DIMINISH THROUGH FRIDAY. SOME LIGHT FREEZING SPRAY IS 
POSSIBLE ACROSS THE EASTERN WATERS TONIGHT.

OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...

FRIDAY NIGHT AND SATURDAY...MODERATE TO HIGH CONFIDENCE.  WEAK LOW 
PRESSURE MOVES ACROSS THE WATERS.  PRESSURE GRADIENT SHOULD REMAIN 
WEAK ENOUGH TO KEEP WINDS BELOW SMALL CRAFT ADVISORY 
THRESHOLDS...BUT MAY SEE SMALL CRAFT SEAS DEVELOP ACROSS OUR 
SOUTHERN WATERS SAT AFTERNOON.  VSBYS WILL ALSO BE RESTRICTED AT 
TIMES IN RAIN AND PATCHY FOG.

SATURDAY NIGHT AND SUNDAY...MODERATE TO HIGH CONFIDENCE.  LOW 
PRESSURE INTENSIFYING EAST OF THE WATERS WILL COMBINED WITH HIGH 
PRESSURE OVER EASTERN CANADA.  THIS WILL GENERATE NORTHERLY SMALL 
CRAFT WIND GUSTS OF 20 TO 30 KNOTS AND LONG FETCH WILL LIKELY 
GENERATE 10 FOOT SEAS ACROSS OUR EASTERN WATERS. THERE IS EVEN 
THE RISK FOR BRIEF GALE FORCE WIND GUSTS ACROSS OUR EASTERN WATERS 
ON SUNDAY.

MONDAY...MODERATE TO HIGH CONFIDENCE.  NORTHERLY SMALL CRAFT WIND 
GUSTS SHOULD DIMINISH DURING THE MORNING.  HOWEVER...LEFT OVER 
EASTERLY SWELL WILL RESULT IN CONTINUED SMALL CRAFT SEAS INTO AT 
LEAST MONDAY EVENING ACROSS OUR EASTERN WATERS.  

TUESDAY AND TUESDAY NIGHT...MODERATE CONFIDENCE.  LOW PRESSURE 
INTENSIFIES ACROSS THE CANADIAN MARITIMES AND DRAGS A STRONG COLD 
FRONT ACROSS THE WATERS.  NORTHWEST GALE FORCE WIND GUSTS WILL BE 
POSSIBLE LATE TUE AND/OR TUE NIGHT.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT FRIDAY FOR ANZ231-232-251.
     SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR 
     ANZ233>235-237-256.
     SMALL CRAFT ADVISORY UNTIL 1 PM EDT FRIDAY FOR ANZ250-254-255.

&&

$$
SYNOPSIS...BELK/FRANK
NEAR TERM...FRANK/BELK
SHORT TERM...BELK
LONG TERM...FRANK
AVIATION...BELK/FRANK
MARINE...BELK/FRANK



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