Area Forecast Discussion
Issued by NWS Boston, MA

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867 FXUS61 KBOX 021951 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 351 PM EDT MON MAY 2 2016 .SYNOPSIS...
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DRY WEATHER BRIEFLY RETURNS THIS EVENING BEFORE A FAST MOVING LOW PRESSURE SYSTEM BRINGS A PERIOD OF RAIN OVERNIGHT INTO TUESDAY MORNING...ESPECIALLY SOUTH OF THE MASSACHUSETTS TURNPIKE. THE RAIN SHOULD BE OVER FOR MOST BY TUESDAY AFTERNOON...BUT IT WILL REMAIN RATHER CLOUDY AND COOL. YET ANOTHER LOW PRESSURE AREA DROPS THROUGH THE GREAT LAKES WEDNESDAY AND STALLS OVER THE WATERS SOUTH OF NEW ENGLAND FOR THURSDAY THROUGH SATURDAY BRINGING A CONTINUED THREAT OF SHOWERS ALTHOUGH THERE WILL BE DRY PERIODS AS WELL. A COLD FRONT WILL MOVE THROUGH NEXT SUNDAY WITH MORE SHOWERS.
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&& .NEAR TERM /UNTIL 1 AM TUESDAY MORNING/...
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THIS EVENING... LEFT OVER SCATTERED SHOWERS SHOULD EXIT THE REGION EARLY THIS EVENING. OTHERWISE...DRY MID LEVELS AND LACK OF FORCING WILL RESULT IN MAINLY DRY WEATHER FOR MUCH OF THE NIGHT. HOWEVER...LOW LEVEL MOISTURE WILL REMAIN TRAPPED BENEATH THE INVERSION SO AN ABUNDANCE OF LOW CLOUDS AND PERHAPS SOME SPOTTY DRIZZLE WILL STILL BE POSSIBLE. LOW TEMPS WILL BE IN THE 40S AND AREAS OF FOG ARE EXPECTED ESPECIALLY ON THE COAST.
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&& .SHORT TERM /1 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
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***PERIOD OF STEADY RAIN EXPECTED ALONG AND SOUTH OF MA TURNPIKE AFTER MIDNIGHT INTO TUESDAY MORNING PARTICULARLY NEAR THE SOUTH COAST*** OVERNIGHT INTO TUESDAY MORNING... ANOTHER WAVE OF LOW PRESSURE OVER THE MID ATLANTIC STATES WILL LIFT NORTHEAST AND PASS SOUTH OF SOUTHERN NEW ENGLAND OVERNIGHT INTO TUESDAY MORNING. BOTH THE GFS/NAM SHOW A DECENT BAND OF MID LEVEL FRONTOGENESIS/OMEGA SOUTH OF THE MA TURNPIKE AND PARTICULARLY NEAR THE SOUTH COAST. WITH ALL THAT SAID...EXPECT A BAND OF RAIN TO OVERSPREAD AREAS ALONG AND SOUTH OF THE MA TURNPIKE TOWARD DAYBREAK. THE RAIN MAY BRIEFLY BE HEAVY AT TIMES...ESPECIALLY NEAR THE SOUTH COAST WHERE THE BEST FORCING/LIFT WILL BE LOCATED. ALONG THE SOUTH COAST...MAY SEE RAINFALL AMOUNTS OF 0.50+ INCHES. MEANWHILE...NORTH OF THE MA TURNPIKE THERE MAY BE A BRIEF PERIOD OF SHOWERS BUT RAINFALL AMOUNTS WILL BE MUCH LIGHTER. TUESDAY AFTERNOON... LOW PRESSURE WILL HAVE PASSED WELL TO OUR EAST TUE AFTERNOON...SO MAINLY DRY WEATHER OTHER THAN PERHAPS A FEW LINGERING SHOWERS ACROSS THE FAR SOUTHEAST NEW ENGLAND COAST. HOWEVER...LOW LEVEL MOISTURE TRAPPED BENEATH THE INVERSION WILL HANG TOUGH WITH LIGHT NORTH TO NORTHEAST WINDS. THE RESULT WILL BE ANOTHER DREARY DAY WITH HIGHS IN THE 50S AND ITS POSSIBLE PORTIONS OF THE EASTERN MA COAST STAY IN THE UPPER 40S.
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&& .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... HIGHLIGHTS... * UNSETTLED WEATHER WITH PERIODS OF SHOWERS AT TIMES INTO NEXT WEEKEND BUT THERE WILL BE DRY PERIODS AS WELL * MOSTLY BELOW NORMAL TEMPS...BUT MILDER NEXT WEEKEND OVERVIEW... MODELS ARE IN GOOD AGREEMENT ON THE OVERALL PATTERN IN THE EXTENDED PERIOD FEATURING A DEVELOPING OMEGA BLOCK ACROSS THE CENTRAL US WITH CLOSED LOWS MOVING INTO THE WEST COAST AND DROPPING SOUTH FROM THE GT LAKES TO THE MID ATLC COAST. STRONG BLOCKING DOWNSTREAM RIDGE OVER THE ATLANTIC WILL ENSURE THAT THIS PATTERN WILL BE SLOW TO BREAK DOWN SO WE ARE LOOKING AT AN UNSETTLED PERIOD INTO THE WEEKEND WITH SHOWERS FROM TIME TO TIME...BUT DRY PERIODS AS WELL. THERE ARE SIGNS THAT THE CLOSED LOW COULD GET KICKED EAST BY THE END OF THE WEEKEND AS NORTHERN STREAM VORTEX DROPS S FROM HUDSON BAY...DELIVERING A COLD FRONTAL PASSAGE. LOW CONFIDENCE ON TEMPS AS WELL AS TIMING AND DETAILS OF PRECIP WHICH WILL DEPEND ON THE PLACEMENT OF THE UPPER LOW AND ATTENDING SFC LOW. DETAILS... TUE NIGHT... LOW PRES S OF NEW ENG TUE EVENING WILL BE MOVING OFFSHORE AS SFC RIDGING BUILDS S INTO NEW ENG. ANY LIGHT RAIN SHOULD BE EXITING THE REGION IN THE EVENING AND MOST OF THE NIGHT SHOULD BE DRY...BUT CANT RULE OUT A FEW SHOWERS...ESPECIALLY INTERIOR AS MID LEVEL SHORTWAVE LIFTS TO THE N OF THE REGION. WEDNESDAY... A MID LEVEL SHORTWAVE MOVING THROUGH MID ATLC REGION THEN NE ALONG THE COAST WILL LIKELY GENERATE ANOTHER SFC WAVE S OF NEW ENG. WEAK WARM ADVECTION COMBINED WITH DEEPENING MOISTURE WILL LIKELY LEAD TO MORE SHOWERS DEVELOPING IN THE AFTERNOON...WITH BEST FOCUS ACROSS THE INTERIOR UNDER THE RIGHT ENTRANCE REGION OF THE UPPER JET. LOW CONFIDENCE TEMP FORECAST GIVEN WIDE RANGE IN MODEL GUIDANCE WITH ECMWF IN THE 40S...GFS 50S AND NAM 60S. LOW LEVEL NE FLOW AND DAMMING SIGNATURE WILL RESULT IN BELOW NORMAL TEMPS BUT LOW CONFIDENCE ON HOW COOL. WE WILL LEAN TOWARD GFS WITH HIGHS IN THE 50S WHICH IS A COMPROMISE...BUT POTENTIAL FOR COOLER EXITS. THURSDAY THROUGH SUNDAY... UNSETTLED CONDITIONS EXPECTED AT TIMES DURING THIS PERIOD BUT LOW CONFIDENCE ON TIMING...DURATION AND EXTENT OF SHOWER ACTIVITY. CLOSED LOW OVER THE OHIO VALLEY WILL GRADUALLY MOVE OFF THE MID ATLC COAST...BUT EXACT LOCATION SOUTH OF NEW ENG IS UNCERTAIN AND THIS WILL IMPACT SENSIBLE WEATHER. WHILE IT MAY BE WET AT TIMES THERE WILL BE PERIODS OF DRY WEATHER AS WELL. IT DOES APPEAR COLD FRONT WILL BE MOVING THROUGH ON SUNDAY WHICH WILL KICK LOW PRES OUT TO SEA BUT BRING A PERIOD OF SHOWERS. FORECAST CONFIDENCE ON TEMPS IS ALSO LOW AND WILL DEPEND ON EXTENT OF CLOUD COVER AND WHETHER THERE IS ANY BREAKS OF SUN. TEMPS WOULD LIKELY REACH WELL INTO THE 60S IN THE INTERIOR WITH ANY SUN...BUT COOLER ALONG THE COAST WITH PERSISTENT E/NE FLOW. MILDEST DAY MAY BE SUN AS WINDS TURN SW AHEAD OF APPROACHING FRONT WITH 70+ DEGREE READINGS POSSIBLE AWAY FROM THE COAST. && .AVIATION /20Z MONDAY THROUGH SATURDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY AFTERNOON/... TONIGHT...MODERATE CONFIDENCE. IFR CONDITIONS MAY IMPROVE TO LOW END MVFR THIS EVENING IN SOME LOCATIONS...BUT THAT IS UNCERTAIN. IFR TO LIFR CONDITIONS LIKELY PERSIST ACROSS THE SOUTHEAST NEW ENGLAND COAST IN LOW CLOUDS AND FOG. DRY WEATHER THIS EVENING OTHER THAN SOME PATCHY DRIZZLE...BUT A BAND OF STEADY WILL MOVE INTO AREAS ALONG AND SOUTH OF MA TURNPIKE BETWEEN 6 AND 12Z. SOME SHOWERS MAY REACH NEAR THE MA/NH BORDER...BUT THE HEAVIEST RAIN WILL BE NEAR THE SOUTH COAST. TUESDAY...MODERATE TO HIGH CONFIDENCE. BULK OF THE RAIN MOVES EAST OF THE REGION TUE MORNING. OTHERWISE...MAINLY DRY WEATHER FOR THE REST OF TUE AFTERNOON BUT MVFR-IFR CONDITIONS WILL LINGER BUT SHOULD SEE A GRADUAL IMPROVEMENT AT LEAST AWAY FROM THE COAST. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. IFR CONDITIONS MAY BRIEFLY IMPROVE TO MVFR AFTER 00Z THIS EVENING IF WINDS CAN TEMPORARILY SHIFT TO THE NORTHWEST. IF SO...IFR CONDITIONS PROBABLY RE-DEVELOP AFTER 8Z WITH THE NEXT BAND OF RAIN. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. IFR CONDITIONS PROBABLY IMPROVE TO LOW END MVFR THIS EVENING. OUTLOOK /TUESDAY NIGHT THROUGH SATURDAY/...MODERATE CONFIDENCE TUE NIGHT AND WEDNESDAY...AREAS OF MVFR/IFR CIGS WITH A FEW SHOWERS AT TIMES. THURSDAY AND FRIDAY...AREAS OF MVFR/IFR WITH SCT SHOWERS.
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&& .MARINE...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY AFTERNOON/...HIGH CONFIDENCE. MAIN CONCERN FOR MARINERS WILL BE AREAS OF FOG...MAINLY LATER TONIGHT INTO TUESDAY. RELATIVELY WEAK PRESSURE GRADIENT WILL KEEP MOST WATERS BELOW SMALL CRAFT ADVISORY THRESHOLDS THROUGH TUE AFTERNOON. HOWEVER...WILL MAINTAIN SCA FOR HAZARDOUS SEAS ACROSS OUR FAR EASTERN WATERS FOR THE FIRST PART OF THE NIGHT FOR MARGINAL 5 FOOT SEAS. WE MAY NEED ADDITIONAL SCA FOR MARGINAL 5 FOOT SEAS LATER TUE ACROSS OUR OUTER-WATERS AGAIN...SO SOMETHING LATER SHIFTS WILL HAVE TO EVALUATE. OUTLOOK /TUESDAY NIGHT THROUGH SATURDAY/...MODERATE CONFIDENCE SURFACE FLOW IS MOSTLY EAST TO NORTHEAST THROUGH THE PERIOD WITH SPEEDS BELOW SCA. SEAS WILL LIKELY APPROACH 5 FT OVER THE OUTER WATERS FROM SWELL GENERATED BY THE PERSISTENT EASTERLY FLOW. VSBYS MAY BE REDUCED AT TIMES IN SHOWERS AND FOG.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM EDT TUESDAY FOR ANZ250-254-255.
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&& $$ SYNOPSIS...FRANK/KJC NEAR TERM...FRANK SHORT TERM...FRANK LONG TERM...KJC AVIATION...FRANK/KJC MARINE...FRANK/KJC

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