Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 280203 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1003 PM EDT FRI MAR 27 2015 .SYNOPSIS... A WEAKENING COLD FRONT WILL MOVE ACROSS NEW ENGLAND THIS AFTERNOON...AND MOVE FARTHER OFFSHORE THIS EVENING. A WEAK LOW PRESSURE MOVING UP THE COAST WILL BRING SOME LIGHT SNOW TO SOUTHERN NEW ENGLAND TONIGHT AND SATURDAY. HIGH PRESSURE WILL PUSH SOUTH OF NEW ENGLAND SUNDAY. ANOTHER BATCH OF PRECIPITATION IS POSSIBLE LATE SUNDAY NIGHT INTO MONDAY AHEAD OF A COLD FRONT. FAST MOVING LOW PRESSURE WILL BRING MORE LIGHT RAIN AND/OR SNOW SHOWERS TUESDAY NIGHT INTO WEDNESDAY. LOW PRES MAY APPROACH LATE NEXT WEEK WITH MORE PRECIPITATION. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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RADAR SCREEN IS MOSTLY CLEAR. JUST SOME LIGHT ECHOES OVER SOUTHERN RI AND ANOTHER AREA STREAMING NORTHEAST ACROSS MARTHAS VINEYARD AND NANTUCKET. ALSO SOME LIGHT ECHOES OVER THE CATSKILLS AND ADIRONDACKS. WITH THE LACK OF SIGNIFICANT ECHOES AT 10 PM...AND BASED ON 12Z GUIDANCE...THE MOST FAVORABLE TIME FOR PCPN DEVELOPMENT WILL BE LATE TONIGHT. THE 00Z HRRR SUGGESTS ROUGHLY 08Z TO 12Z WITH FOCUS ON RI AND EASTERN CT WITH EXPANSION INTO MASS FROM WORCESTER EAST TO BOSTON AND TAUNTON BY 12Z. THE FAVORED AREA WILL BE THE CENTRAL HILLS FROM WORCESTER TO NORTHEAST CT. BASED ON THIS WE HAVE DELAYED THE ONSET OF POPS IN SOUTHERN NEW ENGLAND UNTIL AFTER MIDNIGHT OVERALL AND MOST PLACES AFTER 3 AM. TEMPERATURES MAY BE INITIALLY TOO WARM FOR MUCH ACCUMULATION. OVERALL WE ARE LOOKING AT AN INCH OR LESS FROM SNOW SHOWERS OVERNIGHT.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... UPPER TROUGH OVER THE GREAT LAKES SHIFTS EAST DURING THIS TIME. THIS BRINGS COLD ADVECTION ALOFT...FURTHER DESTABILIZING THE AIRMASS. TEMPERATURES MARGINALLY FAVOR MAINLY SNOW...ESPECIALLY AWAY FROM THE IMMEDIATE COAST. TEMPERATURES WILL BE CRUCIAL TO SNOW ACCUMULATION. COULD EVEN SEE A TRANSITION TO RAIN WITH JUST A LITTLE UPWARD NUDGE. MODEL PRECIPITATION AMOUNTS HAVE INCREASED WITH THIS LATEST GUIDANCE SUITE. THINKING 1-3 INCHES OF SNOW IS MORE THAN JUST A POSSIBILITY. DO NOT HAVE ENOUGH CONFIDENCE TO ISSUE A WINTER WEATHER ADVISORY WITH THIS PACKAGE. HOWEVER... WOULD NOT BE SURPRISED TO SEE A FEW LOCATIONS EXCEED THAT AMOUNT...PARTICULARLY IF THE BAND ESTABLISHES ITSELF ACROSS CENTRAL MA...NORTHEAST CT AND NORTHWEST RI. THESE ARE ALL LOCATIONS WITH HIGHER TERRAIN. CONFIDENCE IN THE STORM TOTAL SNOW ACCUMULATIONS THROUGH SATURDAY IS MODERATE AT BEST. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... HIGHLIGHTS... * SNOW SHOWERS TAPERING OFF DURING SATURDAY NIGHT * A WEAK COLD FRONT WILL MOVE THROUGH ON MONDAY BRINGING SCT SHOWERS * SPRING LIKE TEMPS MOVE IN FOR TUE-THU * ALBERTA CLIPPER MOVES THROUGH TUESDAY NIGHT INTO WED OVERVIEW... 12Z MODEL SUITE AND ENSEMBLES CONTINUE TO SIGNAL A TRANSITION OUT OF AMPLIFIED TROUGHING ACROSS THE EASTERN U.S. EARLY THIS WEEKEND TO A FAST MOVING...ACTIVE STORM TRACK ACROSS THE NORTHERN TIER THROUGH THE REMAINDER OF THIS FORECAST PERIOD. TEMPERATURES TEND WILL TO MODERATE OVER TIME...GETTING CLOSER TO SEASONAL NORMS BY THE MIDDLE OF NEXT WEEK. HOWEVER...WITH FAST W-NW FLOW ALOFT AS H5 RIDGE BUILDS INTO WESTERN CANADA...WILL SEE SEVERAL SHORT WAVES IN THIS FLOW BRINGING PERIODS OF LIGHT RAIN AND/OR SNOW SHOWERS. TIMING THE INDIVIDUAL FEATURES IS TOUGH SO THIS LENDS TO BELOW AVERAGE CONFIDENCE ESPECIALLY TOWARD THE END OF NEXT WEEK. H5 TROUGH MOVES OFF THE COAST ALONG WITH INVERTED SURFACE TROUGH SAT NIGHT INTO SUNDAY. NORTHERN EDGE OF LARGE HIGH PRES PASSING ACROSS THE MID ATLC AND SE U.S. WILL BRING BRIEF DRYING BUT TEMPS WELL BELOW SEASONAL NORMALS. BEYOND THIS...SEVERAL SHORT WAVES WILL MOVE ACROSS WITH PERIODS OF SCT RAIN AND/OR SNOW SHOWERS THROUGH LATE NEXT WEEK AND POSSIBLY BEYOND. DETAILS... SATURDAY NIGHT...MODERATE CONFIDENCE. EXPECT INVERTED TROUGH SITTING ACROSS CENTRAL AND EASTERN AREAS TO SLOWLY PUSH SE DURING THE NIGHT AS OFFSHORE LOW PRES CONTINUES TO MOVE AWAY. LIGHT SNOW WILL CONTINUE THROUGH THE EVENING...THEN SHOULD TAPER OFF FROM NW-SE THROUGH MIDNIGHT OR SO. AS N-NE WIND INCREASING TO 10-15 KT WITH GUSTS CLOSE TO 25 KT ALONG THE IMMEDIATE E MA COAST SAT NIGHT ALONG WITH LINGERING INSTABILITY FROM THE TROUGH...SOME QUESTION AS TO WHETHER THE SNOW THERE COULD BE ENHANCED BY OCEAN EFFECT AS COLDER AIR WORKS IN OVER THE RELATIVELY MILDER WATERS. THE 12Z NAM /AND TO A LESSER DEGREE THE GFS/ BUFKIT SOUNDINGS DO SHOW STEEP LAPSE RATES WHICH WOULD SIGNAL OCEAN EFFECT SNOWFALL. HOWEVER...OCEAN WATERS ARE AT THEIR COLDEST LEVELS OF THE YEAR AND...THANKS TO ARCTIC AIR OF THE LAST COUPLE OF MONTHS...SEA SURFACE TEMPS ARE RATHER LOW MAINLY IN THE MID TO UPPER 30S IN CAPE COD BAY AND ALONG THE PLYMOUTH COUNTY COASTLINE... RANGING TO THE LOWER 40S JUST OFF THE OUTER CAPE AND NANTUCKET. WHEN FACTORING THIS INTO THE LAKE EFFECT TOOL ON BUFKIT...THIS GIVES ONLY MARGINAL CONDITIONS FOR THE OCEAN EFFECT. NOT TOTALLY RULING OUT THE POSSIBILITY OF BRIEF OCEAN EFFECT BANDS SETTING UP ACROSS THE OUTER CAPE...BUT FURTHER W MAY HAVE A TOUGH TIME. WILL STILL NEED TO MONITOR THIS FEATURE THOUGH. OVERNIGHT LOWS EXPECTED TO DROP TO THE UPPER TEENS WELL INLAND TO 25 TO 30 ALONG THE IMMEDIATE S COAST. SUNDAY INTO SUNDAY NIGHT...HIGH CONFIDENCE. WILL SEE DRY BUT COLD CONDITIONS AS HIGH PRES RIDGE AT THE SURFACE AND ALOFT MOVES ACROSS. CLOUDS WILL INCREASE FROM W-E SUN NIGHT AS WARM AIR ADVECTION ALOFT PUSHES IN. HIGHS ON SUNDAY WILL REMAIN CHILLY...ONLY IN THE UPPER 30S TO LOWER 40S. TEMPS WILL FALL BACK TO THE 20S EARLY SUN NIGHT...THEN HOLD STEADY OR RISE A FEW DEGS AS CLOUDS MOVE IN AND SW WINDS PICK UP. A FEW SNOW SHOWERS MIGHT MAKE IT INTO THE E SLOPES OF THE BERKSHIRES TOWARD DAYBREAK MONDAY. MONDAY THROUGH TUESDAY NIGHT...MODERATE CONFIDENCE. H5 SHORT WAVE MOVES OUT OF THE GREAT LAKES AND QUICKLY PUSHES TOWARD THE REGION. MAY SEE SOME WIDELY SCT SNOW SHOWERS AS THE PRECIP BEGINS MON MORNING ACROSS CENTRAL AND WESTERN AREAS...THEN WILL CHANGE OVER TO SCT RAIN SHOWERS BY MIDDAY AS TEMPS RECOVER TO THE 40S. THIS SYSTEM MOVES THROUGH QUICKLY...WITH PRECIP TAPERING OFF MONDAY EVENING. LOWS WILL BOTTOM OUT IN THE UPPER 20S AND 30S MON NIGHT. BRIEF RESPITE IN BETWEEN WEATHER SYSTEMS LATE MON NIGHT INTO TUESDAY AS WEAK RIDGING MOVES ACROSS. HIGHS ON TUESDAY WILL REACH THE UPPER 40S TO LOWER 50S...THOUGH COOLER ACROSS THE CAPE AND ISLANDS. ANOTHER FAST MOVING CLIPPER TYPE SYSTEM WORKS OUT OF THE GREAT LAKES LATER TUE...REACHING THE REGION TUE NIGHT. MODELS HAVING DIFFICULTY WITH TRACK OF THE SYSTEM...THOUGH TIMING IS FAIRLY GOOD WITH PRECIP ARRIVING TUE AFTERNOON AND CONTINUING INTO TUE NIGHT. NOT A WHOLE LOT OF MOISTURE WITH THIS FEATURE SO WILL SEE SCT LIGHT RAIN SHOWERS WHICH WILL CHANGE OVER TO LIGHT SNOW SHOWERS DURING TUE NIGHT. EXPECT PRECIP TO TAPER OFF ACROSS WESTERN AREAS TOWARD DAYBREAK. WEDNESDAY THROUGH FRIDAY...LOW CONFIDENCE. CLIPPER TYPE SYSTEM MOVES OFFSHORE WED MORNING SO EXPECT PRECIP TO TAPER OFF FROM W-E DURING THE MORNING. HIGH PRES RIDGE BUILDS ACROSS FOR THE REMAINDER OF WED INTO WED NIGHT. MID LEVEL RIDGE ALSO BUILDS E...SO WILL SEE TEMPS CLOSER TO SEASONAL NORMALS ON WED. HIGH PRES RIDGE AXIS WILL PUSH OFFSHORE THU NIGHT. TIMING OF NEXT APPROACHING COMPLEX SYSTEM IS VERY MUCH IN QUESTION THOUGH AS H5 TROUGH DIGS OUT OF THE PLAINS STATES TOWARD THE UPPER MISSISSIPPI VALLEY INTO THE WESTERN GREAT LAKES. GFS REMAINS MORE PROGRESSIVE WITH THIS SYSTEM WHILE ECWMF IS SLOWER AND MORE AMPLIFIED. FOR NOW...INTRODUCE CHANCE POPS FOR THU/THU NIGHT...THEN WENT WITH ONLY SLIGHT CHANCE POPS FOR NOW ON FRI. RATHER LOW CONFIDENCE DURING THIS PORTION OF THE FORECAST. STILL PLENTY OF TIME TO WATCH THIS SYSTEM. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...TONIGHT AND FRIDAY... TONIGHT AND SATURDAY...MODERATE CONFIDENCE. TONIGHT...MAINLY VFR TO START WITH SPOTTY MVFR-IFR CIGS ACROSS RI/SE MA. CIGS WILL LOWER TO MVFR-IFR FROM S-N 06-08Z. POCKETS OF IFR-LIFR CIGS/MVFR-IFR VSBYS DEVELOP AROUND OR AFTER 08Z...LOWEST ACROSS E AND CENTRAL MA/RI/NORTHEAST CT. VSBYS WILL LOWER AS -SHSN BREAKS OUT OVERNIGHT WITH INVERTED TROUGH DEVELOPMENT AFTER 3 AM. SATURDAY...EXPECT MVFR CIGS ACROSS CENTRAL AND WESTERN AREAS AND IFR CIGS ACROSS E MA INTO RI DURING THE DAY. MVFR-IFR CIGS ALSO PREVALENT...LOWEST ACROSS E MA/RI. TEMPERATURES SHOULD WARM INTO THE 30S WHICH SHOULD CHANGE THE SNOW TO RAIN IN PLACES ACROSS THE COASTAL PLAIN...WHILE THE INTERIOR REMAINS SNOW. KBOS TAF...MODERATE CONFIDENCE IN TAF. KBDL TAF...MODERATE CONFIDENCE IN TAF. OUTLOOK...SATURDAY NIGHT THROUGH WEDNESDAY... HIGH CONFIDENCE SATURDAY NIGHT THROUGH MONDAY...THEN MODERATE CONFIDENCE MONDAY NIGHT THROUGH WEDNESDAY. SATURDAY NIGHT AND SUNDAY MORNING...VFR CONDITIONS LIKELY. WILL SEE PERIODS OF MVFR CIGS/VSBYS IN SCT SNOW SHOWERS...BEST CHANCE ACROSS RI/E MA. MAY SEE BRIEF LOCAL IFR CONDITIONS ACROSS CAPE COD AND NANTUCKET IN ANY SNOW BANDS THAT MAY FORM ALONG THE COAST. SHOULD SEE IMPROVING CONDITIONS FROM NW-SE FROM MIDNIGHT ONWARD...THOUGH MVFR CIGS MAY LINGER ON THE CAPE AND NANTUCKET THROUGH SUNDAY MORNING. SUNDAY AFTERNOON INTO SUNDAY NIGHT...VFR. LATE SUNDAY NIGHT THROUGH MONDAY NIGHT...VFR DROPPING TO LOCAL MVFR CIGS/VSBYS IN SCT RAIN SHOWERS AS COLD FRONT MOVES THROUGH. CONDITIONS IMPROVE FROM W-E MON NIGHT. TUESDAY AND WEDNESDAY...VFR THROUGH AROUND MIDDAY TUE...THEN LOCAL MVFR CONDITIONS IN DEVELOPING SCT RAIN SHOWERS TUE AFTERNOON. PRECIP CHANGES TO SNOW SHOWERS TUE NIGHT...THEN BACK TO RAIN SHOWERS BEFORE TAPERING OFF AROUND MIDDAY WED WITH IMPROVING CONDITIONS.
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&& .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...TONIGHT AND SATURDAY...MODERATE CONFIDENCE. NORTH WINDS PICK UP AS COLDER AIR MOVES SOUTH AND A DISTURBANCE PASSES WELL OFFSHORE. EXPECTING WINDS GUSTING TO 25 KNOTS ON THE EASTERN OUTER WATERS WITH SEAS LINGERING AT 5-7 FEET. THERE IS POTENTIAL FOR WINDS GUSTING TO 25 KNOTS ON CAPE COD BAY AND NANTUCKET SOUND AS WELL. SMALL CRAFT ADVISORIES CONTINUE FOR THE OUTER MA AND RI COASTAL WATERS. OUTLOOK...SATURDAY NIGHT THROUGH WEDNESDAY... MODERATE CONFIDENCE THROUGH WEDNESDAY. SATURDAY NIGHT...N-NE WINDS BRIEFLY DIMINISH EARLY SAT NIGHT THEN INCREASE AGAIN. GUSTS TO 25-30 KT ACROSS MOST OF THE OPEN WATERS AFTER MIDNIGHT. SEAS UP TO 6-8 FT ACROSS THE OUTER WATERS. SUNDAY THROUGH MONDAY...EXPECT N WINDS TO SHIFT TO SW DURING SUNDAY BUT WILL CONTINUE TO GUST TO 25-30 KT. SEAS REMAIN AOA 5 FT ON THE OPEN WATERS. MONDAY NIGHT-TUESDAY...WINDS SHIFT TO W...CONTINUE TO GUST TO 25-30 KT HIGHEST ON THE OUTER WATERS. SEAS REMAIN AOA 5 FT. WINDS MAY BEGIN TO DIMINISH TUE NIGHT. WEDNESDAY...EXPECT N-NW WINDS TO DIMINISH BELOW SMALL CRAFT CRITERIA. SEAS MAY LINGER AROUND 5 FT MAINLY OVER THE SOUTHERN OUTER WATERS BUT SHOULD SUBSIDE LATE IN THE DAY. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ235-237- 250-254>256. && $$ SYNOPSIS...BELK/EVT NEAR TERM...WTB SHORT TERM...BELK LONG TERM...EVT AVIATION...BELK/EVT MARINE...BELK/EVT

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