Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 022000 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 400 PM EDT SUN AUG 2 2015 .SYNOPSIS... THE THREAT OF SHOWERS AND THUNDERSTORMS RETURNS MON EVENING INTO TUE. AFTER A DRY DAY WEDNESDAY...A PERIOD OF UNSETTLED WEATHER IS POSSIBLE SOMETIME THURSDAY INTO SATURDAY...BUT CONFIDENCE IS LOW ON THE TIMING OF POTENTIAL WET WEATHER. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... QUIET AFTERNOON ACROSS SOUTHERN NEW ENGLAND WITH TEMPERATURES INTO THE MID 80S MOST LOCATIONS. MOSTLY SUNNY SKIES ASIDE FROM SOME SCATTERED DIURNAL CUMULUS. A WARMER NIGHT IS EXPECTED WITH SOUTHWEST FLOW SLOWLY INCREASING THE DEWPOINTS ACROSS SOUTHERN NEW ENGLAND. MAIN CONCERN WILL BE THIS INCREASING MOISTURE AND FLOW OFF THE WATER RESULTING IN FOG...LOW CLOUDS...AND DRIZZLE DEVELOPING ON THE SOUTH COAST. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... AREAS OF FOG...LOW CLOUDS...AND DRIZZLE ON THE SOUTH COAST WILL DIMINISH BY MIDDAY. THEN...AN ANOMALOUS UPPER LOW IN ONTARIO WILL HAVE THE MOST INFLUENCE ON OUR WEATHER...PARTICULARLY MONDAY NIGHT. AS LOW PRESSURE MOVES INTO QUEBEC ON MONDAY IT WILL PULL A COLD FRONT THROUGH NEW YORK STATE AND PORTIONS OF NORTHERN NEW ENGLAND. MUCH IF NOT ALL OF MONDAY WILL BE DRY FOR SOUTHERN NEW ENGLAND AS THE FRONT STAYS TO THE WEST OF THE REGION UNTIL LATE IN THE EVENING. IF ANYTHING...A FEW STRAY SHOWERS AND THUNDERSTORMS MAY MOVE INTO NORTHWESTERN MASSACHUSETTS BY LATE IN THE AFTERNOON TO EARLY EVENING AS THE FRONT APPROACHES. LIKELY A HOT...HUMID SUMMERY DAY WITH HIGHS IN THE UPPER 80S AWAY FROM THE SOUTH COAST WHERE ONSHORE FLOW WILL KEEP TEMPERATURES IN THE LOWER 80S. MONDAY NIGHT IS SOMEWHAT OF A PUZZLE. THE COLD FRONT MOVES SLOWLY INTO SOUTHERN NEW ENGLAND OVERNIGHT AND STALLS BY EARLY TUESDAY MORNING. ORDINARILY THIS WOULD NOT BE A PARTICULARLY GOOD TIME FOR STRONG STORMS OR EVEN THUNDERSTORMS AND THE MODELS TEND TO INDICATE AS MUCH WITH VERY LITTLE IN THE WAY OF QPF EXHIBITED IN QUITE A FEW OF THE MODELS. THIS IS A BIT OF A RED FLAG AS IF WE ARE GOING TO HAVE STORMS WE HAVE TO HAVE SOME QPF. HOWEVER...WE ALSO HAVE INCREASING INSTABILITY THROUGH THE NIGHT AS THE DEWPOINTS SHOOT UP AHEAD OF THE FRONT. ALL THE MODELS ARE INDICATING THE CAPE INCREASING TO 1000-2000 J/KG AS WE MOVE THROUGH THE NIGHT. MID LEVEL LAPSE RATES AND 0-6KM BULK SHEAR VALUES ALSO INCREASE AFTER 06Z TUESDAY. SO CANNOT RULE OUT A STRONG TO SEVERE THUNDERSTORM ACROSS THE AREA AND EXPECT AT LEAST SHOWERS AND THUNDERSTORMS FOR MUCH OF SOUTHERN NEW ENGLAND DURING THE OVERNIGHT PERIOD. THE GREATEST THREAT WITH THESE STORMS WILL BE GUSTY TO DAMAGING WINDS AND PERHAPS SOME SMALL HAIL. && .LONG TERM /TUESDAY THROUGH SUNDAY/... HIGHLIGHTS... * SHOWERS AND THUNDERSTORMS POSSIBLE TUESDAY * UNSETTLED WEATHER POSSIBLE FOR THE END OF THE WEEK INTO SAT...BUT CONFIDENCE IS LOW ON TIMING * TEMPS TRENDING BELOW NORMAL THE END OF THE WEEK INTO THE WEEKEND OVERVIEW... MODELS AGREE ON LARGE SCALE PATTERN THROUGH THE END OF THE WEEK FEATURING A BROAD TROF ACROSS THE GT LAKES INTO THE NORTHEAST...BUT THERE ARE SIGNIFICANT DIFFERENCES ON THE HANDLING OF SHORTWAVES ROTATING THROUGH THE FLOW AND TIMING/TRACK OF A WAVE OF LOW PRES APPROACHING THE REGION TOWARD THE END OF THE WEEK. THIS HAS AN IMPACT ON SENSIBLE WEATHER FOR THE END OF THE WEEK INTO THE WEEKEND...ESPECIALLY REGARDING THE TIMING OF POTENTIAL WET WEATHER. ABOVE NORMAL TEMPS TUE WILL TREND BELOW NORMAL TOWARD THE END OF THE WEEK INTO THE WEEKEND. DAILIES... TUESDAY... COLD FRONT WILL BE NEARLY STATIONARY OR MOVING VERY SLOWLY E ACROSS SNE DURING THE DAY AS IT WAITS FOR UPSTREAM SHORTWAVE ENERGY TO MOVE THROUGH. POTENTIAL EML ADVECTS INTO THE REGION WITH MID LEVEL LAPSE RATES NEAR 7 C/KM. THIS WILL RESULT IN SBCAPES UP TO 2000 J/KG ACROSS E NEW ENG WHERE DEWPOINTS CLIMB NEAR 70 AHEAD OF THE FRONT. 0- 6KM SHEAR NEAR 40 KT WHERE MAX INSTABILITY SUGGESTING POTENTIAL FOR STRONG TO SEVERE TSTMS...MAINLY E HALF NEW ENG. THE ONE RED FLAG IS THE GFS/ECMWF NOT GENERATING ANY QPF AS TIMING OF THE FRONT AND HOW QUICKLY DRIER AIR MOVES IN FROM THE WEST IS NOT CERTAIN SO NOT A HIGH CONFIDENCE FORECAST. IF STORMS DO MATERIALIZE...TIMING WILL BE EARLIER THAN WHAT IS NORMALLY EXPECTED...LIKELY IN THE MORNING THROUGH EARLY AFTERNOON AS DRIER AIR WILL BE MOVING IN FROM THE WEST PUSHING INSTABILITY AXIS OFFSHORE. TEMPS WILL REACH WELL INTO THE 80S WITH A FEW LOCATIONS POSSIBLY TOUCHING 90. WEDNESDAY... MID LEVEL SHORTWAVE AND COOLER AIR ALOFT MOVE THROUGH NEW ENG. LOW PROB FOR A FEW SHOWERS AS ATTENDING SFC TROF PROVIDES WEAK LOW LEVEL CONVERGENCE...BUT EXPECT MAINLY DRY WEATHER. TEMPS RANGING FROM MID 70S HIGHER TERRAIN TO LOWER 80S COASTAL PLAIN. THURSDAY THROUGH SATURDAY... LOW CONFIDENCE FORECAST AS MODELS DIFFER ON HANDLING OF SHORTWAVE ENERGY AND LOW PRES APPROACHING THE REGION. IT IS LIKELY THAT A PERIOD OF UNSETTLED WEATHER WILL AFFECT THE REGION BUT TIMING IS UNCERTAIN. GFS IS AN OUTLIER AND BRINGS A SLUG OF RAIN THROUGH ON THU WHILE ECMWF/GGEM/UKMET BRING RAIN MOSTLY ON FRI...POSSIBLY LINGERING INTO SAT. WE HAVE HIGHEST POPS FRI INTO SAT BUT CONFIDENCE IS LOW. TEMPS BELOW NORMAL. SUNDAY...LOOKS MAINLY DRY WITH HIGH PRES MOVING INTO THE REGION. TEMPS SLIGHTLY BELOW NORMAL. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. THIS AFTERNOON...VFR WITH DRY WEATHER AND GOOD VSBY. LOW RISK OF SEABREEZE EASTERN MA. HIGH FORECAST CONFIDENCE. TONIGHT...VFR AND DRY WEATHER FOR MOST OF THE REGION. AREA OF CONCERN IS SOUTH COAST OF RI AND MA WHERE IFR IN LOW CIGS/FOG AND DRIZZLE IS POSSIBLE. HIGH CONFIDENCE INLAND...LOWER CONFIDENCE ALONG THE SOUTH COAST. MONDAY...IFR POSSIBLE SOUTH COAST OF MA AND RI IN PATCHY FOG AND DRIZZLE. IMPROVING AS THE DAY PROGRESSES. VFR ELSEWHERE WITH LOW RISK OF T-STORMS WESTERN MA AND CT LATE IN THE DAY. MODERATE CONFIDENCE. MONDAY NIGHT...MAINLY VFR. MVFR/IFR CONDITIONS WITH SCT SHRA AND TSRA. LOW RISK OF A STRONG STORM TOWARDS DAYLIGHT TUESDAY MORNING. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. LOW RISK OF SEABREEZE THIS AFTERNOON. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK /TUESDAY THROUGH FRIDAY/... TUESDAY...MODERATE CONFIDENCE. VFR MUCH OF THE TIME. MVFR/IFR WITHIN ANY SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. A LOW RISK FOR A STRONG STORM IS POSSIBLE. WEDNESDAY...MODERATE CONFIDENCE. VFR. THURSDAY INTO FRIDAY...LOW CONFIDENCE. A PERIOD OF SHOWERS AND MVFR/IFR POSSIBLE BUT TIMING IS UNCERTAIN. LATEST INDICATIONS ARE THAT BEST CHANCE FOR WET WEATHER WILL BE ON FRI. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM /THROUGH MONDAY NIGHT/...MODERATE CONFIDENCE. TONIGHT...QUIET BOATING WEATHER WITH INCREASING SOUTHERLY TO SOUTHWESTERLY WINDS. LOW CLOUDS...FOG...AND DRIZZLE ARE LIKELY TO DEVELOP ALONG THE SOUTH COAST OF MASS AND RHODE ISLAND LIMITING VISIBILITIES AT TIMES. MONDAY...SOUTH-SOUTHWESTERLY WINDS AND SEAS INCREASE THROUGHOUT THE DAY IN ADVANCE OF AN APPROACHING COLD FRONT. SMALL CRAFT CONDITIONS EXPECTED BY LATE AFTERNOON SO HAVE HOISTED A SMALL CRAFT ADVISORY FOR THE OUTER WATERS AND FOR RHODE ISLAND AND BLOCK ISLAND SOUND FOR LATE MONDAY AFTERNOON THROUGH MONDAY NIGHT. MONDAY NIGHT...SMALL CRAFT ADVISORY UP FOR OUTER WATERS AND RHODE ISLAND AND BLOCK ISLAND SOUNDS. SEAS INCREASE TO 5 TO 6 FEET BY EARLY TUESDAY MORNING WITH SOUTHERLY WINDS GUSTING TO NEAR 25 KTS AS A COLD FRONT BEGINS TO MOVE OVER THE WESTERN WATERS. OUTLOOK /TUESDAY THROUGH FRIDAY/...MODERATE CONFIDENCE. TUESDAY...MODERATE CONFIDENCE. A PERIOD OF PREFRONTAL SW GUSTS TO 25 KT POSSIBLE ESPECIALLY OVER THE S COASTAL WATERS INTO TUE EVENING...THEN WINDS DIMINISHING AND BECOMING WEST OVERNIGHT. SEAS BUILDING TO 5-7 FT OVER THE OUTER SOUTHERN WATERS. WEDNESDAY...MODERATE CONFIDENCE. W/SW WINDS BELOW SCA BUT GUSTS TO 20 KT POSSIBLE. SEAS SUBSIDING. THURSDAY INTO FRIDAY...LOW CONFIDENCE. WINDS AND SEAS WILL DEPEND ON TRACK AND TIMING OF LOW PRES APPROACHING THE REGION. COULD SEE A PERIOD OF GUSTY NE WINDS...ESPECIALLY FRI. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 PM MONDAY TO 6 AM EDT TUESDAY FOR ANZ235-237-250-254>256. && $$ SYNOPSIS...KJC/RLG NEAR TERM...RLG SHORT TERM...RLG LONG TERM...KJC AVIATION...KJC/RLG MARINE...KJC/RLG

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