393  
FXUS61 KBOX 302005  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TAUNTON MA  
405 PM EDT SUN APR 30 2017  
   
SYNOPSIS
 
 
HIGH PRESSURE MOVES OFF THE COAST THIS EVENING, AND A WARM  
FRONT MOVES INTO SOUTHERN NEW ENGLAND MONDAY. THE FRONT LIFTS  
TO THE NORTH MONDAY NIGHT FOLLOWED BY A COLD FRONT LATE MONDAY  
NIGHT AND EARLY TUESDAY. ANOTHER STORM MOVES TOWARD SOUTHERN  
NEW ENGLAND LATE THURSDAY OR FRIDAY, AND COULD LINGER NEARBY  
INTO SATURDAY.  
 

 
   
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
 
 
MODEST ELEVATED INSTABILITY COMBINED WITH LOW LEVEL THETA-E  
ADVECTION WAS ENOUGH FOR CONVECTIVE COMPLEX WITH SHOWERS AND  
SCT T-STORMS TO HOLD TOGETHER AS IT MOVED ACROSS SNE THIS  
AFTERNOON. THE SHOWERS HAVE MOVED OFFSHORE BUT ADDITIONAL  
SHOWERS ARE MOVING INTO THE REGION FROM THE WEST WHICH MAY  
LINGER THROUGH LATE AFTERNOON.  
 
HIGH PRES WILL MOVE OFFSHORE TONIGHT WITH A WARM FRONT  
APPROACHING SNE LATE TONIGHT. LOW CLOUDS WILL DEVELOP OVERNIGHT  
FROM SOUTH TO NORTH WITH PATCHY DRIZZLE LIKELY GIVEN ABUNDANT  
LOW LEVEL MOISTURE AND MID LEVEL DRY AIR MOVING UP FROM THE  
SOUTH. ALSO, CAN'T RULE OUT A FEW SHOWERS OVERNIGHT AS 40 KT  
LOW LEVEL JET MOVES INTO THE REGION WITH INCREASING K INDICES.  
 
THE ASTRONOMICAL TIDE WILL BE ON THE HIGH SIDE AGAIN...11.45  
FEET AT BOSTON AT 3:35 AM, BUT LITTLE IN THE WAY OF STORM SURGE  
IS EXPECTED, WITH SOUTHEAST WINDS AROUND 10 MPH SO NOT  
EXPECTING MUCH IN THE WAY OF SPLASHOVER.  
 

 
   
SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/
 
 
MONDAY...  
THE WARM FRONT MOVES INTO SNE BUT WILL LIKELY STALL ACROSS THE  
REGION. LOW CONFIDENCE TEMP FORECAST IN THE VICINITY OF THE  
FRONT WHERE LARGE TEMP GRADIENT IS EXPECTED. SOUTH AND WEST OF  
THE FRONT TEMPS MAY SOAR INTO THE LOWER 70S WITH THE LOWER CT  
VALLEY HAVING THE BEST CHANCE TO REALIZE THESE WARMER TEMPS.  
FURTHER NE, ESPECIALLY ACROSS NORTH CENTRAL AND NE MA TEMPS MAY  
REMAIN IN THE 50S WITH E/NE WINDS AS FRONT WILL LIKELY STRUGGLE  
TO MAKE IT THAT FAR NORTH. WHERE THE FRONT SETS UP WILL BE  
CRITICAL TO THE TEMP FORECAST.  
 
EXPECT AREAS OF LOW CLOUDS, DRIZZLE AND PATCHY FOG IN THE  
MORNING, THEN SOME IMPROVEMENT INTO THE AFTERNOON, ESPECIALLY  
LOWER CT VALLEY AND SOUTH COAST WHERE SOME BREAKS OF SUN ARE  
POSSIBLE. LOW CLOUDS MAY PERSIST ALONG AND NORTH OF THE WARM  
FRONT, ESPECIALLY NE MA. MODELS INDICATE PRONOUNCED MID LEVEL  
DRYING MOVING INTO THE REGION MON ALONG WITH DECREASING K  
INDICES IN THE COASTAL PLAIN. THIS SHOULD PRECLUDE ANY  
CONVECTION OR SHOWER ACTIVITY WITH MAIN AXIS OF DEEPER MOISTURE  
AND INSTABILITY WELL TO THE WEST, MOVING ACROSS WESTERN AND  
CENTRAL NY IN THE AFTERNOON.  
 
MONDAY NIGHT...  
COLD FRONT APPROACHES FROM THE WEST AND MOVES INTO SNE LATE MON  
NIGHT. HI-RES GUIDANCE INDICATING A LINE OF CONVECTION WEAKENING  
AS IT MOVES EAST FROM CENTRAL NY AS NO SFC INSTABILITY IS  
FORECAST IN NEW ENG. HOWEVER, LOW LEVEL JET OF 50+ KTS, DEEP  
MOISTURE PLUME AND ELEVATED INSTABILITY WILL HELP TO BRING  
SHOWERS AND A FEW T-STORMS INTO THE REGION. PWAT PLUME IS 3SD  
ABOVE NORMAL WHILE WIND ANOMALIES WEAKEN TO +2SD WHICH IS  
SUFFICIENT FOR LOCALLY BRIEF HEAVY RAINFALL. THERE MAY BE SOME  
GUSTY SW WINDS DEVELOPING IN THE COASTAL PLAIN AS THE LOW LEVEL  
JET MOVES IN. A LOW LEVEL INVERSION MAY KEEP THE STRONGER GUSTS  
FROM REACHING THE SURFACE BUT ANY CONVECTION MAY HELP WITH  
MOMENTUM TRANSFER. SOMETHING THAT NEEDS TO BE MONITORED. MILD  
NIGHT AS WARM FRONT LIFTS TO THE NORTH. TEMPS REMAINING IN THE  
50S WITH SOME LOWER 60S POSSIBLE.  
 

 
   
LONG TERM /TUESDAY THROUGH SUNDAY/
 
 
OVERVIEW...  
 
STILL SEEING VARIATIONS IN THE MODEL SOLUTIONS FOR LATER THIS  
WEEK, ALTHOUGH SOME DETAILS ARE STARTING TO EMERGE WITH GREATER  
CONFIDENCE INTO THURSDAY MORNING. 30/00Z OPERATIONAL GFS  
CONTINUES TO BE OUT OF STEP WITH THE GEFS MEAN, AS WELL AS THE  
ECMWF AND CMC. FAVORED A CONSENSUS APPROACH THROUGH WEDNESDAY,  
THEN LEANED A BIT MORE TOWARD A NON-GFS SOLUTION FRIDAY INTO  
SATURDAY. LOWER THAN AVERAGE CONFIDENCE IN THE FRIDAY-SATURDAY  
FORECAST.  
 
DETAILS...  
 
MONDAY NIGHT-TUESDAY...MODERATE CONFIDENCE.  
LOW PRESSURE WILL PUSH ACROSS THE GREAT LAKES INTO ONTARIO AND  
WESTERN QUEBEC DURING THIS TIMEFRAME.  
 
STRONG SW LOW LEVEL JET WILL RESULT IN EXCELLENT MOISTURE  
TRANSPORT, AND HELP TO ORGANIZE MODEST INSTABILITY AHEAD OF A  
COLD FRONT. NOT EXPECTING SEVERE WEATHER, SINCE THE PRIMARY TIME  
PERIOD WOULD BE MONDAY NIGHT, BUT WITH 45-55 KT WINDS, CANNOT  
COMPLETELY DISMISS THE POSSIBILITY.  
 
SHOWERS MOVE OUT OF OUR REGION TUESDAY MORNING, BUT THE COLD  
FRONT WILL LAG A BIT LONGER. GUSTY SOUTHWEST WINDS SHOULD  
CONTINUE THROUGH THE DAY. ONCE THE SUNSHINE BREAKS OUT,  
EXPECTING ANOTHER DAY OF ABOVE NORMAL TEMPERATURES.  
 
WEDNESDAY...MODERATE CONFIDENCE.  
 
THIS IS STILL LOOKING LIKE A MAINLY DRY PERIOD. CYCLONIC FLOW  
ALOFT WILL MEAN A PERIOD OF DIURNAL CLOUDS, MOSTLY TOWARD NW MA.  
ANY ISOLATED SHOWERS WHICH MIGHT DEVELOP WOULD BE CONFINED TO  
FAR WESTERN MA. NEAR NORMAL TEMPERATURES.  
 
THURSDAY-FRIDAY...MODERATE CONFIDENCE.  
 
HAVE GREATER CONFIDENCE EARLY THURSDAY MORNING WILL START OUT  
DRY. LOTS OF INGREDIENTS LINING UP FOR A PERIOD OF WET WEATHER,  
THE QUESTION WHICH IS HARDER TO PIN DOWN IS THE TIMING. HAVE  
INCREASING RAINFALL CHANCES FROM SW TO NE THROUGH THE DAY  
THURSDAY, LEADING INTO THE MORE LIKELY PERIOD OF RAINFALL  
THURSDAY NIGHT INTO FRIDAY. RAINFALL COULD BE HEAVY AT TIMES.  
 
SATURDAY...LOW CONFIDENCE.  
 
THIS PERIOD REMAINS COMPLICATED. GFS STILL HAS A VERY WET  
SOLUTION, WHILE THE CMC, ECMWF, AND GEFS SUGGEST A CLOSED 850 MB  
LOW PASSES BY TO OUR WEST, WHICH WOULD FORCE A DRY SLOT INTO  
SOUTHERN NEW ENGLAND DURING THE. AS PREVIOUSLY MENTIONED,  
FAVORED THE DRIER NON-GFS SOLUTIONS, BUT DID NOT GO WITH A  
COMPLETELY DRY FORECAST. IT WILL LIKELY BE ANOTHER DAY OR TWO  
BEFORE THIS DISCREPANCY START TO GET RESOLVED.  
 

 
   
AVIATION /19Z SUNDAY THROUGH FRIDAY/
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
SHORT TERM...THROUGH MONDAY.  
 
THROUGH 00Z...BRIEF MVFR IN SHOWERS EASTERN MA UNTIL 19Z,  
OTHERWISE VFR.  
 
TONIGHT...MODERATE CONFIDENCE.  
CONDITIONS DETERIORATING TO MVFR/IFR AFTER MIDNIGHT AS STRATUS  
AND PATCHY DRIZZLE DEVELOPS. AREAS OF FOG DEVELOPING ALONG THE  
SOUTH COAST TOWARD DAYBREAK.  
 
MONDAY...MODERATE CONFIDENCE.  
IFR/LIFR CIGS WITH PATCHY FOG IN THE MORNING. CONDITIONS MAY  
IMPROVE TO MVFR/VFR IN THE AFTERNOON CT VALLEY AND NEAR THE  
SOUTH COAST, BUT LIKELY REMAINING IFR CENTRAL AND NE MA. PATCHY  
DRIZZLE IN THE MORNING ALONG WITH A FEW SHOWERS POSSIBLE.  
 
MONDAY NIGHT...MODERATE CONFIDENCE.  
WIDESPREAD IFR/LIFR LIKELY EASTERN NEW ENG AND LOWERING TO IFR  
IN THE WEST WITH AREA OF SHOWERS AND A FEW T-STORMS MOVING  
THROUGH FROM WEST TO EAST. GUSTY SW WINDS DEVELOPING IN THE  
COASTAL PLAIN. AREAS OF LLWS NEAR THE SOUTH COAST WITH SW WINDS  
45-55 KT AT 2K FT.  
 
KBOS TAF...HIGH CONFIDENCE IN TRENDS. LOWER CONFIDENCE IN  
TIMING.  
 
KBDL TAF...HIGH CONFIDENCE IN TRENDS. LOWER CONFIDENCE IN  
TIMING.  
 
OUTLOOK /TUESDAY THROUGH FRIDAY/...  
 
TUESDAY...HIGH CONFIDENCE.  
 
MVFR-IFR CONDITIONS LINGER EARLY MORNING IN LEFTOVER SHOWERS,  
THEN IMPROVING TO VFR THROUGH MIDDAY. LLWS WITH SW WINDS  
45-55 KT ACROSS SOUTH COASTAL AREAS POSSIBLE THROUGH 16Z,  
HIGHEST ACROSS THE ISLANDS.  
 
WEDNESDAY...HIGH CONFIDENCE. VFR.  
 
WEDNESDAY NIGHT-THURSDAY...MODERATE CONFIDENCE.  
 
VFR EXPECTED THROUGH THE PERIOD, ALTHOUGH CIGS LOWER DURING  
THURSDAY. INCREASING COVERAGE OF RAIN FROM SW TO NE THURSDAY,  
WITH MVFR VSBYS IN HEAVIER RAIN DURING THE AFTERNOON. -RA AND  
PATCHY FOG LINGERS WITH AREAS OF MVFR CIGS/VSBYS INTO THURSDAY  
NIGHT.  
 

 
   
MARINE
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
SHORT TERM /THROUGH MONDAY NIGHT/...  
 
TONIGHT...HIGH CONFIDENCE.  
MAINLY SE WINDS LESS THAN 20 KTS WITH SEAS BELOW SCA. VSBYS  
LOWERING IN FOG TOWARD DAYBREAK OVER THE SOUTH COASTAL WATERS.  
PATCHY DRIZZLE DEVELOPING.  
 
MONDAY...MODERATE CONFIDENCE.  
WARM FRONT MOVES INTO THE WATERS MONDAY. SE WINDS BECOME SW  
SOUTH OF THE FRONT, MAINLY OVER THE SOUTHERN WATERS, WHILE  
EASTERLY WINDS WILL PERSIST ACROSS NE MA WATERS. WIND SPEEDS  
SHOULD REMAIN BELOW SCA. VISIBILITY RESTRICTIONS IN AREAS OF  
DRIZZLE AND PATCHY FOG THROUGH EARLY MONDAY AFTERNOON.  
 
MONDAY NIGHT...MODERATE CONFIDENCE.  
SE WINDS BECOME SW ACROSS NE MA WATERS, OTHERWISE INCREASING SW  
WINDS WITH GUSTS 25-30 KT DEVELOPING, ESPECIALLY SOUTH COASTAL  
WATERS WITH BUILDING SEAS. SCA WILL BE NEEDED WITH LOW RISK FOR  
GALES BUT STRONG INVERSION WILL LIKELY KEEP WINDS BELOW GALE  
FORCE. VSBYS REDUCED IN SHOWERS AND FOG. ISOLD T-STORMS  
POSSIBLE.  
 
OUTLOOK /TUESDAY THROUGH FRIDAY/...  
 
MONDAY NIGHT...MODERATE CONFIDENCE.  
 
INCREASING SW WINDS AHEAD OF A COLD FRONT APPROACHING THE WATERS,  
WITH GUSTS UP TO 30 KT. ROUGH SEAS BUILDING ACROSS THE OUTER  
COASTAL WATERS, TOO. SHOWERS LIKELY WITH SCATTERED  
THUNDERSTORMS. VISIBILITY RESTRICTIONS IN PRECIPITATION. SMALL  
CRAFT ADVISORIES LIKELY.  
 
TUESDAY...MODERATE CONFIDENCE.  
 
IMPROVING CONDITIONS AS SHOWERS MOVE OUT OF THE AREA DURING THE  
MORNING. GUSTY SW WINDS UP TO 30 KT CONTINUE, BEFORE  
DIMINISHING TUESDAY NIGHT. ROUGH SEAS LINGER ACROSS THE OUTER  
COASTAL WATERS. SMALL CRAFT ADVISORIES LIKELY FOR THE SOUTHERN  
COASTAL WATERS.  
 
WEDNESDAY...MODERATE CONFIDENCE. WINDS CONTINUE TO DIMINISH  
THROUGH WEDNESDAY NIGHT, BUT SEAS WILL TAKE A WHILE LONGER.  
 
THURSDAY...MODERATE CONFIDENCE.  
WINDS EXPECTED TO REMAIN LESS THAN 20 KT, WITH SEAS LESS THAN  
4 FEET.  
 

 
   
BOX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
MA...NONE.  
RI...NONE.  
MARINE...NONE.  
 

 
 

 
SYNOPSIS...KJC  
NEAR TERM...KJC  
SHORT TERM...KJC  
LONG TERM...BELK  
AVIATION...BELK/KJC  
MARINE...BELK/KJC  
 
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