Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 011753 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 153 PM EDT WED JUL 1 2015 .SYNOPSIS... A FRONTAL SYSTEM WILL BRING SHOWERS...AND A CHANCE FOR STRONG TO SEVERE THUNDERSTORMS...INTO THIS AFTERNOON. THIS FRONT STALLS NEAR THE SOUTH COAST THURSDAY...BEFORE MOVING OFFSHORE THURSDAY NIGHT. ASIDE FROM A SPOT SHOWER POSSIBLE SATURDAY...MAINLY DRY AND SEASONABLE WEATHER IS EXPECTED INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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150 PM UPDATE... RADAR IS FAIRLY QUIET ACROSS SNE OTHER THAN AN ISOLD SHOWER/TSTM ACROSS CENTRAL MA. AIRMASS IS DESTABILIZING WITH MLCAPES APPROACHING 1000 J/KG AND SBCAPES 1500 J/KG ACROSS CENTRAL/W MA AND N CT UNDER SOMEWHAT FAVORABLE MID LEVEL LAPSE RATES 6-6.5 C/KM. PLENTY OF DEEP LAYER SHEAR WITH 0-6KM SHEAR AROUND 40 KT SO POTENTIAL FOR A FEW STRONG TO SEVERE THUNDERSTORMS WILL CONTINUE. NOTING SOME DRIER AIR PUNCHING INTO SW CT AND MODELS SHOW PRONOUNCED DRYING MOVING ALONG THE S COAST AND SE MA THIS AFTERNOON WHICH WILL LIKELY PRECLUDE ANY CONVECTIVE DEVELOPMENT IN THIS AREA. MAIN THREAT FOR STRONG TO SEVERE STORMS WILL BE NORTH AND NW OF THE DRY SLOT ACROSS CENTRAL AND W MA. BEST LOW LEVEL SHEAR AND HELICITY HAS MOVED E OF NEW ENG SO DAMAGING WIND AND HAIL WILL BE PRIMARY THREAT WITH ANY STRONG STORMS THAT DEVELOP.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... A FEW LEFTOVER SHOWERS...AND PERHAPS A THUNDERSTORM OR TWO...ARE STILL POSSIBLE EARLY THIS EVENING. OTHERWISE EXPECTING DRY CONDITIONS FOR MOST OF TONIGHT. A COLD FRONT WILL BE SLOWLY CROSSING OUR REGION TONIGHT...LIKELY STALLING NEAR THE SOUTH COAST OF NEW ENGLAND FOR A TIME LATE TONIGHT INTO THURSDAY. LATEST GUIDANCE CONTINUES TO ADVERTISE A DRY ATMOSPHERE...SO EXPECTING MOST OF THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGHLIGHTS... * SEASONABLE TO SLIGHTLY ABOVE SEASONABLE TEMPERATURES EXPECTED. * LOW CHANCE OF A SHOWER MAINLY ON THE 4TH. OVERVIEW AND MODEL PREFERENCES...MODELS CONTINUE TO INDICATE A SHIFT IN THE OVERALL PATTERN FROM A HIGHLY AMPLIFIED REGIME TO ONE THAT IS MORE PROGRESSIVE AND ZONAL. THIS IS IN SPITE OF THE FAIRLY ROBUST RIDGES IN PLACE ACROSS THE E PACIFIC AND THE BERMUDA HIGH N OF THE ANTILLES. ALTHOUGH THIS MORE ZONAL FLOW PATTERN DOES TAKE ON A LONGWAVE TROF FEATURE BETWEEN THE TWO RIDGES...IT IS NOT OVERLY DEEP/SHARP. THIS ALLOWS THE RIDGING ASSOCIATED WITH THE BERMUDA HIGH TO BECOME THE DOMINANT PLAYER FOR OUR SENSIBLE WX INTO EARLY NEXT WEEK. AT THIS POINT A MUCH DEEPER NRN STREAM VORTEX WILL BE IN PLAY...AND WILL TRANSITION THE DRIER AND MORE STABLE REGIME ACROSS THE NE CONUS TO A MORE UNSETTLED PATTERN. THE ONLY FLY IN THE OINTMENT IS ON THE 4TH UNFORTUNATELY...BUT MORE ON THAT BELOW. DETAILS... THU NIGHT INTO FRI...THE FIRST IN A SERIES OF MID LVL RIDGES WILL BE MOVING THROUGH THE ZONAL FLOW PATTERN DURING THIS PERIOD. THIS INTRODUCES A MAINLY DRY PERIOD WITH WEAK HIGH PRES IN PLACE ACROSS SRN NEW ENGLAND. THERE REMAINS A FRONT STALLED TO THE S...WITH SOME UPPER LVL MOISTURE SUGGESTING SOME PARTLY CLOUDY CONDITIONS. OTHERWISE...H85 TEMPS BETWEEN +10C AND +12C SUGGEST HIGHS NEAR TO SLIGHTLY ABOVE SEASONAL NORMALS ACROSS THE REGION AWAY FROM THE COAST WERE SEA BREEZES ARE LIKELY. FRI NIGHT INTO SAT NIGHT...WITH THIS NEARLY ZONAL FLOW IN PLACE...IT/S NOT JUST RIDGING...BUT WEAK SHORTWAVES TO CONCERN OURSELVES WITH. MODELS CONTINUE TO INDICATE A WEAK PACKET OF ENERGY PASSING THROUGH THE REGION DURING THE EARLY WEEKEND. THE OVERALL COLUMN IS RELATIVELY DRY...WITH PWATS NEAR NORMAL FOR EARLY JULY. HOWEVER...WITH THE FRONT STALLED TO THE S...THE DEVELOPMENT OF A WEAK WAVE OF LOW PRES COULD BRING ABOUT MODEST LIFT ALONG THE SRN TIER OF SRN NEW ENGLAND DURING THE DAY SAT. THERE ARE TWO CAMPS HERE...GFS AND SOME ENSEMBLE MEMBERS WITH QPF ACROSS THE REGION...AND THE ECMWF AND OTHER ENSEMBLE MEMBERS WITHOUT. THEREFORE...CONFIDENCE NOT HIGH ON PRECIP CHANCES...BUT IT IS LIKELY TO NOT BE A WASHOUT IN EITHER CASE GIVEN HOW WEAK THE WAVE IS AND THE LACK OF MOISTURE. JUST A FEW PASSING SHOWERS TO CONTEND WITH. SUN INTO MON...AS DEEP ER WAVE FORMS ACROSS THE CANADIAN PRAIRIE LANDS...A SECONDARY RIDGE WILL AMPLIFY IN RESPONSE TO WARM ADVECTION FROM THE BERMUDA HIGH TO THE SE. THIS WILL YIELD ANOTHER PERIOD OF DRIER AND WARMER CONDITIONS ACROSS SRN NEW ENGLAND. BETTER CHANCES FOR TEMPS INCHING ABOVE NORMAL DURING THIS STRETCH...THANKS TO MORE INFLUENCE FROM THE SE. TOWARD MID WEEK...THE AFOREMENTIONED WAVE WILL BEGIN A SLIDE TO THE E. THIS PARTICULAR FEATURE IS MORE ROBUST THAN PREVIOUS WAVES...SO IT/S LIKELY A PERIOD OF WETTER AND UNSETTLED WX WILL RETURN BY THE MID PORTION OF NEXT WEEK. UNCERTAINTY IN EXACT TIMING. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. THROUGH 00Z...A MIX OF MVFR/VFR CIGS. SCT T-STORMS EXPECTED TO REDEVELOP MAINLY CENTRAL AND W MA. S WIND GUSTS TO 20-25 KT. TONIGHT...MODERATE CONFIDENCE. MAINLY VFR...BUT PATCHY MVFR/IFR STRATUS AND FOG DEVELOPING. THU...HIGH CONFIDENCE. VFR. BUT MVFR CIGS/VSBYS MAY DEVELOP OVER ACK LATE IN THE DAY ALONG WITH THE THREAT OF A FEW SHOWERS. THU NIGHT...MODERATE CONFIDENCE. VFR...BUT AREAS OF MVFR/IFR POSSIBLE CAPE/ISLANDS. SHOWERS LIKELY FOR ACK POSSIBLY REACHING THE S COAST AND CAPE COD. KBOS TERMINAL...HIGH CONFIDENCE. KBDL TERMINAL...HIGH CONFIDENCE. OUTLOOK...FRIDAY THROUGH SUNDAY... HIGH CONFIDENCE. MAINLY VFR. A FEW SHOWERS POSSIBLE ON SAT...BUT MAINLY DRY OTHERWISE. SEA BREEZES LIKELY MOST DAYS.
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&& .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. ISSUED SCA FOR NE MA COASTAL WATERS IN RESPONSE TO SE GUSTS TO 25 KT WHICH WILL LIKELY PERSIST THROUGH MID AFTERNOON BEFORE DIMINISHING A BIT AND SHIFTING TO S. WINDS AND SEAS WILL INCREASE IN RESPONSE TO A FRONTAL SYSTEM APPROACHING THE WATERS LATER TODAY. SMALL CRAFT ADVISORIES HAVE BEEN EXTENDED FOR THE SOUTHERN OUTER WATERS AND RHODE ISLAND AND BLOCK ISLAND SOUNDS. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... THU NIGHT INTO FRI...HIGH CONFIDENCE. WEAK RIDGE OF HIGH PRES WILL BE MOVING OVER THE WATERS THROUGH THE PERIOD. ANY LINGERING SWELL ABOVE 5 FT WILL RECEDE OVERNIGHT WITH QUIET BOATING WX EXPECTED THROUGH THE REST OF FRI. SAT AND SUNDAY...MODERATE CONFIDENCE. THIS PERIOD WILL BE DEPENDENT ON HOW CLOSELY A WEAK WAVE OF LOW PRES PASSES TO THE S COAST ON SAT. IF IT PASSES CLOSE ENOUGH...A PERIOD OF SWELLS EXCEEDING 5 FT IS POSSIBLE. OTHERWISE...MAINLY QUIET BOATING WEATHER WILL CONTINUE ESPECIALLY AS HIGH PRES RETURNS SUNDAY. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 3 PM EDT THURSDAY FOR ANZ235-237. SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ250- 251. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THURSDAY FOR ANZ254>256. && $$ SYNOPSIS...BELK/DOODY NEAR TERM...KJC SHORT TERM...BELK LONG TERM...DOODY AVIATION...KJC/DOODY MARINE...BELK/KJC/DOODY

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