Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBOX 280721 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 321 AM EDT SAT MAR 28 2015 .SYNOPSIS... OFFSHORE LOW PRESSURE WILL PASS WELL OFFSHORE BUT SPREAD LIGHT SNOW AND RAIN SHOWERS INTO SOUTHERN NEW ENGLAND. HIGH PRESSURE BUILDS OVER THE EASTERN USA WITH DRY WEATHER. 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 PM THIS EVENING/... THROUGH 8 AM... RADAR SHOWS TWO AREAS OF LIGHT PCPN MOVING INTO SOUTHERN NEW ENGLAND. ONE GLIDES UP FROM THE SOUTHWEST INTO SOUTH COASTAL SECTIONS...WHILE THE SECOND SWEEPS SOUTHEAST FROM THE ADIRONDACKS INTO WESTERN MASS. OBSERVATIONS SHOW LIGHT RAIN SHOWERS ON THE SOUTH COAST AND FLURRIES MOVING FROM NEW YOUR INTO THE BERKSHIRES. EXPECT LIGHT PCPN TO MOVE DEEPER INTO SOUTHERN NEW ENGLAND EARLY THIS MORNING. LOW CONFIDENCE ON THE EXACT TIMING...BUT HIGHER CONFIDENCE ON THE TREND. TODAY... UPPER TROUGH OVER THE GREAT LAKES BRINGS COLD ADVECTION SURFACE AND ALOFT...DESTABILIZING THE AIRMASS. VERTICAL PROFILES SHOW A DEEP LAYER OF MOISTURE THROUGH THE DAY ALONG WITH 20-30 MB/HOUR OF LIFT. LARGE SCALE AND MESOSCALE MODELS HAVE BEEN HINTING AT A SURFACE TROUGH DEVELOPING OFF THE EAST COAST OF MASS AND THEN PIVOTING ACROSS EASTERN MASS AND RI. ALL OF THIS WOULD SUPPORT DEVELOPING PCPN. THE UPPER TROUGH AND DESTABILIZATION WOULD FAVOR A CONVECTIVE MODE /SHOWERS/ RATHER THAN STRATIFORM. SURFACE TEMPS WOULD SUGGEST RAIN ALONG THE COAST AND AND SNOW INLAND. TEMPS AT OR ABOVE 950 MB WOULD SUGGEST SNOW ALL AREAS EXCEPT CAPE COD/ISLANDS. PTYPE AND POTENTIAL ACCUMULATIONS WILL HINGE ON THESE TEMPERATURES. WE SPECULATE THAT MANY OF THE SNOW SHOWERS MAY LEAVE A SLUSHY ACCUMULATION...BUT LESS THAN WHAT WE WOULD HAVE SEEN 1 1/2 MONTHS AGO. THE BEST CHANCE OF ACCUMULATIONS WILL COME IN THE HILL COUNTRY SUCH AS THE WORCESTER HILLS IN MASS AND THE HILLS IN NORTHEAST CT/NORTHWEST RI. ACCUMULATIONS OF AN INCH OR TWO ARE POSSIBLE BY EVENING...BUT BECAUSE THESE ARE SHOWERS THE ACCUMULATIONS SHOULD NOT BE UNIFORM. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... TONIGHT...LOW CONFIDENCE. OFFSHORE LOW MOVES OFF THROUGH THE MARITIMES WHILE UPPER TROUGH MOVES OVERHEAD. THIS MAINTAINS THE POTENTIAL FOR PCPN WHILE COOLING NIGHTIME TEMPS WOULD FAVOR SNOW OR RAIN CHANGING TO SNOW. THE PIVOTING SURFACE TROUGH SHOULD MOVE OFFSHORE AFTER MIDNIGHT WITH ANY PCPN OVER OUR AREA DIMINISHING. BASED ON EXPECTED TEMPS AND LIGHT PCPN THROUGH THE DAY AND NIGHT WE PROJECT STORM TOTAL OF 1-3 INCHES IN THE HILLS AND AROUND 1 INCH IN THE LOWER TERRAIN. NORTH WINDS WILL PULL /YET AGAIN/ COLDER THAN NORMAL AIR ACROSS THE REGION. TEMPERATURES UPSTREAM OVERNIGHT HAVE BEEN IN THE TEENS AND LOWER 20S. CLOUDS MAY SLOW COOLING A LITTLE...SO WE FAVORED 15 TO 25 DEGREES. SUNDAY...HIGH CONFIDENCE. HIGH PRESSURE BUILDS OVER THE EASTERN USA SURFACE AND ALOFT. THIS SHOULD BRING SUNNY SKIES MOST AREAS. SOME LINGERING CLOUDS ARE POSSIBLE IN THE MORNING IN EASTERN MASS. TEMPS ALOFT SUGGEST HIGHS IN THE 30S...BUT WARM ADVECTION LATE IN THE DAY MAY NUDGE VALUES TO AROUND 40. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... HIGHLIGHTS... * 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... SUNDAY NIGHT...HIGH CONFIDENCE. CLOUDS WILL INCREASE FROM W-E SUN NIGHT AS WARM AIR ADVECTION ALOFT PUSHES IN. 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 /08Z SATURDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...TODAY THROUGH SUNDAY TODAY... MVFR CIGS MOVING INTO THE SOUTH COAST AND THE BERKSHIRES. VFR IN BETWEEN. EXPECT A TREND TO MVFR CIGS/VSBYS IN RAIN AND SNOW SHOWERS WITH OCCASIONAL IFR IN SNOW SHOWERS. TONIGHT... MIXED MVFR/IFR CIGS AND VSBYS CONTINUE EARLY NIGHT...SIMILAR TO CONDITIONS DURING THE DAY BUT WITH BROADER FAVORING OF SNOW AS TEMPERATURES COOL. TREND SHIFTS TO VFR AFTER MIDNIGHT AS DRIER AIR MOVES IN. SUNDAY...VFR. IFR MAY LINGER NEAR THE CAPE AND ISLANDS IN THE MORNING BUT WITH THE TREND TO VFR BY AFTERNOON. KBOS TAF...MODERATE CONFIDENCE IN TAF. KBDL TAF...MODERATE CONFIDENCE IN TAF. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY... HIGH CONFIDENCE SUNDAY NIGHT THROUGH MONDAY...THEN MODERATE CONFIDENCE MONDAY NIGHT THROUGH WEDNESDAY. SUNDAY NIGHT THROUGH MONDAY NIGHT...VFR EARLY BUT 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. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...TODAY THROUGH SUNDAY MODERATE CONFIDENCE TODAY AND TONIGHT. HIGH CONFIDENCE SUNDAY. NORTH WINDS INCREASE AS LOW PRESSURE PASSES WELL OFFSHORE. EXPECT THESE WINDS WILL FREQUENTLY GUST TO 25 KNOTS ON MOST MASSACHUSETTS WATERS AND POSSIBLY RI SOUND. GUSTS TO 30 KNOTS POSSIBLE ON THE OUTER WATERS EAST OF MASS. SEAS WILL BE 5-8 FEET ON ALL EXPOSED WATERS AND 1 TO 4 FEET ON THE REMAINING WATERS. WINDS ON THE NEARSHORE WATERS DIMINISH THIS EVENING WHILE WINDS FARTHER OFFSHORE MAY TAKE UNTIL LATE TONIGHT TO FALL BELOW 25 KNOTS. UNDER THESE CONDITIONS WE EXPECT SEAS TO REMAIN AT THEIR DAYTIME LEVELS. HIGH PRESSURE BUILDS OVER THE WATERS SUNDAY. WINDS AND SEAS SHOULD DIMINISH AT THAT TIME. LINGERING 5 FOOT SEAS ON THE OUTER WATERS DURING THE AFTERNOON. SMALL CRAFT ADVISORIES HAVE BEEN EXPANDED TO ALL WATERS EXCEPT NARRAGANSETT BAY...AND EXTENDED INTO SUNDAY FOR MOST WATERS. OUTLOOK...SUNDAY 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 THIS EVENING FOR ANZ235- 237-250-254>256. && $$ SYNOPSIS...WTB/EVT NEAR TERM...WTB SHORT TERM...WTB LONG TERM...EVT AVIATION...WTB/EVT MARINE...WTB/EVT

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.