Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 281903 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 303 PM EDT THU APR 28 2016 .SYNOPSIS...
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* UPDATES TO NEAR AND SHORT TERM FORECAST PORTIONS ONLY... HIGH PRESSURE FROM CENTRAL CANADA TO NEW ENGLAND WILL BE IN CONTROL THROUGH SATURDAY...YIELDING DRY WEATHER WITH MILD AFTERNOONS AND CHILLY NIGHTS. A RETURN TO COOL AND UNSETTLED WEATHER EXPECTED SUNDAY INTO MONDAY AS LOW PRESSURE TRACKS TO THE SOUTH OF NEW ENGLAND...THEN IMPROVING CONDITIONS FOLLOW TUESDAY.
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&& .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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3 PM UPDATE... CLOUDS THICKENING FROM THE S/W UP AGAINST HIGH PRESSURE AND DRY- SINKING AIR. THIS ACTIVITY PARENT WITH MID LEVEL VORTEX ENERGY STRETCHING THROUGH THE CONFLUENT FLOW PATTERN ACROSS AND TO THE E OF NEW ENGLAND. INTO THIS EVENING ONLY EXPECTING THICKENING CLOUDS OVER S NEW ENGLAND AND REMAINING MOSTLY DRY. THERE IS THE PRESENCE OF SOME MID LEVEL FORCING ALLOWING FOR LIFT OF UPSLOPING MOISTURE RESULTING IN RADAR RETURNS AT HIGHER LEVELS OVER THE LOWER HUDSON RIVER VALLEY. WHILE AN ABUNDANCE OF DRY AIR...CAN NOT RULE OUT IT REACHING THE GROUND. WILL HINT CHANCE POPS OVER THE HARTFORD METRO AND POINTS S/W. TONIGHT... WHERE CAN WE EXPECT TO SEE CLOUDS AND WET WEATHER? CONFIDENCE IS TOWARDS THE S/W WHERE THE MID-UPPER LEVEL CONFLUENCE RELAXES IN A REGIME OF WEAK ISENTROPIC ASCENT AND SOME MID-LEVEL FORCING PARENT WITH STRETCHED VORTEX ENERGY. ANY OUTCOMES WOULD BE LIGHT MAINLY OVER S/W CT N OF A W TO E FRONTAL BOUNDARY OFF THE DELMARVA / NJ COASTLINE. NOT A ROBUST EVENT. HARDLY A WASHOUT. THINKING NUISANCE. SPRINKLES TO VERY LIGHT SHOWERS. FOCUS MAINLY SW CT. DRY ELSEWHERE PER ACCOMPANYING AIRMASS AND SUBSIDENCE ASSOCIATED WITH HIGH TO N. NON-NAM CONSENSUS. SO OVERALL A MOSTLY DRY AND QUIET NIGHT FOR MUCH OF S NEW ENGLAND. INCREASING AND THICKENING CLOUDS FROM THE S/W. SUBSEQUENTLY MILDER WITH LOWS AROUND THE UPPER 30S S BUT COOLER N UNDER THE INFLUENCE OF HIGH PRESSURE AND LIGHT WINDS UNDER LESS CLOUDS. CAN NOT RULE OUT RADIATIONAL COOLING ACROSS THE HIGH TERRAIN AND WITHIN INTERIOR VALLEYS OF N MASSACHUSETTS WHICH COULD DRIVE LOWS DOWN TO THE UPPER 20S IF CONDITIONS ARE RIGHT.
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&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
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FRIDAY... KEEPING IT DRY WITH CLOUDS LINGERING. POTENT MID LEVEL VORTEX OUT OF THE S GREAT LAKES INVOKES WEAK LOW PRESSURE ACROSS THE APPALACHIANS TOWARDS THE DELMARVA LATE. ISALLOBARIC RESPONSE MAINTAINS DRY AIR AND HIGH PRESSURE ACROSS MUCH OF NEW ENGLAND WITH A COMPONENT OF DOWN-SLOPING AIR AND SUBSIDENCE THROUGH THE LOW LEVELS. CONSIDERING THE E ONSHORE FLOW AND THE LIKELIHOOD OF CLOUDS LINGERING MAY NUDGE A FEW DEGREES LOWER ON HIGHS FORECAST AROUND THE UPPER 50S. FRIDAY NIGHT... RENEWED FOCUS OF LIGHT SHOWERY WEATHER S/W. VORTEX AND ACCOMPANYING SURFACE LOW EMERGING OFF THE DELMARVA WITH PARENT JET ENERGY AND DYNAMICS. CRUX OF FORCING / ISENTROPIC ASCENT SLIDES S OF THE REGION AS HIGH PRESSURE AND DRY AIR REMAIN INFLUENTIAL N/E WITH SINKING AIR IN THE LOW LEVELS. AM CONFIDENT THAT SW CT COULD SEE LIGHT SHOWERS. MAJORITY OF WET WEATHER WILL STAY S AND OFFSHORE. MAJORITY OF THE ACTIVITY DURING THE EVENING WITH CLOUDS IN GREATER ABUNDANCE S/W. SO OVERALL A DRY FORECAST FOR MUCH OF S NEW ENGLAND. A CLEARING TREND WITH HIGH PRESSURE BUILDING BACK IN AND SINKING AIR BY MIDNIGHT AND CONTINUING THROUGH SATURDAY MORNING. WINDS TURNING LIGHT WITH CLEARING...COULD SEE SOME PLACES RADIATE OUT DECENTLY AS LOWS DROP INTO THE 30S. FOCUS MAINLY N/E ESPECIALLY WITH SANDY SOILS.
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&& .LONG TERM /SATURDAY THROUGH THURSDAY/... HIGHLIGHTS... * DRY WITH SEASONABLE TEMPS AWAY FROM THE COAST SAT * COOLER WITH UNSETTLED WEATHER SUN/MON * IMPROVING CONDITIONS TUE WITH MILDER TEMPS OVERVIEW... MEDIUM RANGE GUIDANCE IN GENERAL AGREEMENT ON DEVELOPMENT OF GREAT LAKES MID LEVEL TROF LATE IN THE WEEKEND WHICH EVENTUALLY AMPLIFIES DURING EARLY NEXT WEEK AS SERIES OF SHORTWAVES ROTATE THROUGH. TIMING AND AMPLITUDE OF THE INDIVIDUAL SHORTWAVES IS UNCERTAIN BUT GENERAL THEME WILL BE A TREND TOWARD COOLER UNSETTLED WEATHER SUN INTO MON AS BOUNDARY SETS UP TO THE SOUTH WITH MOIST LOW LEVEL EASTERLY FLOW DEVELOPING AS LOW PRES TRACKS S OF NEW ENG. IMPROVEMENT EXPECTED TUE BUT IT IS UNCERTAIN IF MILD AND DRY WEATHER HANGS ON INTO WED AS ANOTHER LOW PRES MAY BE LURKING JUST OFFSHORE. DETAILS... FRI NIGHT INTO SAT... MID LEVEL SHORTWAVE APPROACHING FROM THE WEST AND MOVING OFF NJ COAST FRI NIGHT WILL TRIGGER AN AREA OF SHOWERS MOSTLY SW OF NEW ENG BUT THERE IS A CHANCE THE NORTHERN EDGE COULD CLIP PORTIONS OF CT INTO S RI FRI EVENING. THEN MAINLY DRY CONDITIONS EXPECTED LATER FRI NIGHT INTO SAT AS HIGH PRES IN CONTROL. TEMPS SAT WILL REACH INTO THE 60S INTERIOR LOCATIONS BUT SEABREEZES WILL HOLD TEMPS IN THE 50S NEAR THE COAST. SUN INTO MON... MODELS HAVE TRENDED TOWARD A COOLER AND WETTER SCENARIO WITH OVERRUNNING OF SFC BOUNDARY TO THE SOUTH AS LOW PRES TRACKS TO THE SOUTH. TIMING OF STEADIEST RAINFALL IS UNCERTAIN AND WHILE IT WON/T BE RAINING ALL THE TIME...EXPECT PERIODS OF SHOWERS SUN INTO MON AND POPS WERE INCREASED ACCORDINGLY. LOW LEVEL EASTERLY FLOW WILL RESULT IN BELOW NORMAL TEMPS AND LATER FORECASTS MAY NEED TO LOWER TEMPS FURTHER. COULD SEE DAYTIME TEMPS HOLDING IN THE 40S ACROSS INTERIOR. TUE INTO WED... LOOKS MOSTLY DRY AND MILDER TUE AS LOW PRES DEPARTS BUT STILL CANT RULE OUT A BRIEF SHOWER AS MID LEVEL TROF REMAINS TO THE WEST WITH SHORTWAVE ENERGY MOVING THROUGH. LOW CONFIDENCE FORECAST WED. GFS IS DRY AND MILD WITH SOUTHERLY FLOW BUT ECMWF HAS LOW PRES JUST OFFSHORE WITH RAIN THREATENING AT LEAST THE COAST WITH COOL NE FLOW. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/...
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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 FRIDAY NIGHT/...HIGH CONFIDENCE. VFR THROUGH FRIDAY NIGHT. LOW RISK MVFR ACROSS S/W CT TONIGHT AND AGAIN FRIDAY NIGHT. E/SE FLOW TONIGHT BECOMING MORE E AND BREEZY INTO FRIDAY EVENING BEFORE BECOMING LIGHT AND BACKING N INTO SATURDAY MORNING. KBOS TERMINAL...VFR. SEA-BREEZE ASHORE. FLOW TO REMAIN E THROUGH FRIDAY EVENING. STRONGEST DURING THE AFTERNOON TO EVENING HOURS ON FRIDAY. KBDL TERMINAL...VFR. OUTLOOK /SATURDAY THROUGH TUESDAY/... SATURDAY...MODERATE CONFIDENCE. VFR. SUNDAY INTO MONDAY...MODERATE CONFIDENCE. DETERIORATING CONDITIONS WITH MVFR AND LOCALIZED IFR POSSIBLE WITH PERIODS OF 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 FRIDAY NIGHT/...HIGH CONFIDENCE. MAINLY QUIET BOATING WEATHER AS HIGH PRESSURE REMAINS DOMINANT. THERE IS A LOW RISK OF RAIN SHOWERS ON THE S WATERS CLOSER TO BLOCK / LONG ISLAND TONIGHT AND AGAIN FRIDAY NIGHT. E/SE FLOW BECOMING BREEZY INTO FRIDAY AFTERNOON AND EVENING WITH POSSIBLE GUSTS UP TO 20 KTS DURING WHICH TIME ISOLATED 5 FOOT SEAS ARE POSSIBLE OVER THE WATERS S OF ISLANDS. WINDS BACK NE INTO SATURDAY MORNING. OUTLOOK /SATURDAY THROUGH TUESDAY/... SATURDAY...QUIET BOATING WEATHER WITH WINDS AND SEAS BELOW SCA. SUNDAY INTO MON...INCREASING EASTERLY WINDS LATE SUN INTO MON AS LOW PRES TRACKS TO THE SOUTH. A PERIOD OF SCA GUSTS POSSIBLE SUN NIGHT INTO MON DEPENDING ON TRACK AND INTENSITY OF LOW PRES. VSBYS REDUCED AT TIMES IN SHOWERS AND PATCHY FOG.
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&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...KJC/SIPPRELL NEAR TERM...SIPPRELL SHORT TERM...SIPPRELL LONG TERM...KJC AVIATION...KJC/SIPPRELL MARINE...KJC/SIPPRELL

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