Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 282028 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 428 PM EDT SAT MAR 28 2015 .SYNOPSIS...
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STRONG LOW PRESSURE WELL EAST OF NANTUCKET WILL CONTINUE MOVING EAST WHILE A SECONDARY LOW FORMS SOUTHEAST OF NANTUCKET OVERNIGHT. THIS WILL KEEP SOME LIGHT SNOW FALLING ACROSS SOUTHEASTERN NEW ENGLAND WELL INTO THE NIGHT. HIGH PRESSURE BUILDS OVER THE EASTERN USA WITH DRY WEATHER ON 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 PRESSURE MAY APPROACH LATE NEXT WEEK WITH MORE PRECIPITATION.
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&& .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 4 PM UPDATE... INTENSE LOW PRESSURE WAS LOCATED WELL OFFSHORE...ABOUT 200 MILES EAST OF NANTUCKET WHERE THERE HAVE BEEN LIGHTNING STRIKES IN PAST FEW HOURS. LUCKILY WE ARE ONLY HAVING TO DEAL WITH A WEAK TROUGH OF LOW PRESSURE EXTENDING WESTWARD FROM THIS STORM AND LOCATED ALONG THE SOUTH COAST OF NEW ENGLAND LATE THIS AFTERNOON. LIGHT SNOW HAS BEEN OCCURRING ALL DAY OVER MUCH OF THE REGION...EXCEPT RAIN ON OUTER CAPE COD AND NANTUCKET. IT HAS ACCUMULATED 2 TO 3 INCHES IN THE HIGHER ELEVATIONS BUT EVEN THAT HAS MAINLY BEEN ON GRASSY AREAS AND NOT PAVEMENT. IN MOST AREAS IT HAS MELTED ON ROAD SURFACES WITH TEMPERATURES HANGING IN THE LOW TO MID 30S. AS OF 4 PM...BANDS OF SNOW WERE PICKING UP IN INTENSITY ACROSS EASTERN MA IN THE BOSTON METRO AREA...AND IN CENTRAL AND EASTERN CT. HIGH RESOLUTION WRF...INCLUDING THE ARW-EAST AND NMM... ALL DEPICT THIS QUITE WELL. THEY SHOW IT EXPANDING EASTWARD INTO RI AND PORTIONS OF CENTRAL/EASTERN MA BETWEEN NOW AND 8 PM. WITH TEMPERATURES FALLING DURING THAT TIME FRAME...WE COULD PICK UP ANOTHER INCH OR TWO AND IT COULD BEGIN TO STICK ON ROADWAYS. BETWEEN 8 PM AND MIDNIGHT...SNOW SHOULD BEGIN TO BECOME MORE SCATTERED AND EVENTUALLY END FROM NW TO SE BETWEEN MIDNIGHT AND DAYBREAK. WATER VAPOR SATELLITE IMAGERY SHOWS A VORTICITY MAX NEAR PHILADELPHIA THAT WILL BE CLOSING OFF A 500 MB LOW SOUTH OF THE REGION OVERNIGHT AND A SECONDARY SURFACE LOW PRESSURE MAY FORM JUST SOUTHEAST OF THE BENCHMARK OF 40N 70W. THIS WILL KEEP THE CHANCE OF SNOW LINGERING THE LONGEST FROM BLOCK ISLAND TO NANTUCKET...UNTIL ABOUT DAYBREAK. STILL ONLY EXPECTING .1 TO .2 INCHES OF LIQUID...OR UP TO AN INCH OR TWO OF SNOW THERE. THERE MAY BE A BRIEF GUSTY PERIOD OF UP TO 15-25 MPH OVERNIGHT AS THE GRADIENT TIGHTENS BETWEEN THE OFFSHORE LOW AND STRONG HIGH PRESSURE OVER THE OHIO VALLEY. LOWS RANGING FROM TEENS NORTHWEST TO NEAR 30 CAPE AND ISLANDS. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... HIGH PRESSURE WILL BECOME CENTERED OVER THE MID ATLANTIC AND SOUTHEASTERN STATES SUNDAY...WITH A RIDGE EXTENDING NORTHEASTWARD INTO NEW ENGLAND. LINGERING CLOUDS IN SOUTHEAST MA WILL GIVE WAY TO SUNSHINE BY MID TO LATE MORNING. ELSEWHERE A SUNNY DAY IS FORECAST WITH HIGHS FROM 35 TO 40. SUNDAY NIGHT...SKIES WILL BE MOSTLY CLEAR TO START...ALLOWING TEMPERATURES TO DROP INTO THE 20S BUT SOUTHWEST WINDS AND INCREASING CLOUD COVER AHEAD OF AN APPROACHING COLD FRONT WILL PREVENT THEM FROM FALLING FURTHER LATER AT NIGHT. THERE IS A SMALL CHANCE OF A FEW SNOW SHOWERS TOWARD DAYBREAK MONDAY IN FAR WESTERN SECTIONS OF MA AND CT. && .LONG TERM /MONDAY THROUGH SATURDAY/... HIGHLIGHTS... * A WEAK COLD FRONT WILL MOVE THROUGH ON MONDAY BRINGING SCT SHOWERS * MODERATING SPRING-LIKE TEMPS INTO NEXT WEEK * ALBERTA CLIPPER MOVES THROUGH TUESDAY NIGHT INTO WED * INCREASING CHANCES FOR PRECIP SOMETIME DURING THE EASTER WEEKEND OVERVIEW... ACTIVE PATTERN APPEARS TO BE SETTING UP OVER SOUTHERN NEW ENGLAND NEXT WEEK. FIRST SYSTEM IS ON MONDAY FOLLOWED BY A WAVE TUESDAY NIGHT AND FINALLY A SYSTEM THURS/FRIDAY. OVERALL...A QUICK MOVING RIDGE AND ASSOCIATED HIGH WILL DEVELOP ON SUNDAY BEFORE NORTHWEST FLOW SETS UP AS RIDGE BUILD OVER THE ROCKIES. THIS WILL ALLOW FOR SEVERAL WAVES TO PUSH THROUGH. AS MENTIONED EARLIER...LOW PRESSURE SYSTEM WILL MOVE ACROSS NORTHERN NEW ENGLAND DRAGGING A COLD FRONT WITH IT ON MONDAY. NEXT AN ALBERTA CLIPPER WILL DIVE INTO SOUTHERN NEW ENGLAND BY LATE TUESDAY INTO WEDNESDAY. LASTLY A NORTHERN AND SOUTHERN STREAM MERGER APPEARS TO APPROACH THURSDAY/FRIDAY. IT IS DIFFICULT TO ANY DETERMINISTIC MODEL OVER ANOTHER SINCE ALL FALL WITHIN THE MULTI-CENTER ENSEMBLE SPREAD. NEVERTHELESS... THE ECMWF HAS BEEN MORE CONSISTENT WITH SOME...NOT ALL...FEATURES ACROSS THE REGION THAN THE GFS AND HAS MORE SUPPORT FROM THE CMC/UKMET. NOTHING SHOWS GOOD MULTI-DAY CONTINUITY AND THE TREND HAS BEEN BOTH SLOWER AND QUICKER... DEPENDING ON THE SYSTEM OF INTEREST. THEREFOR TRENDED TOWARD WPC GUIDANCE FOR THIS FORECAST. DETAILS... * SUNDAY NIGHT INTO TUESDAY...HIGH CONFIDENCE. NEXT UPPER LEVEL SHORTWAVE WILL QUICKLY MOVE THROUGH NW FLOW ALOFT LATE SUNDAY INTO MONDAY. GUIDANCE SEEMS TO BE IN BETTER AGREEMENT WITH THIS SYSTEM KEEPING MOST OF SUN PM DRY AND BRINGING PRECIP EARLY MONDAY MORNING. SURFACE LOW ACROSS THE GREAT LAKES WILL PASS JUST NORTH OF SNE...DRAGGING ASSOCIATED COLD FRONT WITH IT. TEMPS AT THE ONSET LOOK TO BE COOL THEN WARM UP DURING THE DAY ON MONDAY PRIOR TO FRONTAL PASSAGE. AT THE ONSET OF PRECIP...EXPECT A FEW SNOW SHOWERS...BUT THEN TRANSITIONING TO RAIN FAIRLY QUICKLY AS TEMPS WARM UP. MOISTURE IS MARGINAL SO COVERAGE MAY BE MORE SCT ALONG THE FRONT. EXPECT VERY MINOR ACCUMULATIONS WITHIN ANY SNOW SHOWERS. BEHIND THE FRONT...WESTERLY WINDS WILL BE ON THE INCREASE AND GUSTING TO 25-30 MPH. TUESDAY WILL BE MOSTLY DRY AS SOUTHERN NEW ENGLAND IS SQUEEZED BETWEEN TWO SYSTEMS. WINDS WILL CONTINUE TO GUST THROUGH THE DAY. TEMPS WILL BE IN THE MID TO UPPER 40S BUT WITH THE WIND...IT WILL FEEL LIKE THE UPPER 30S. CLOUDS WILL BE ON THE INCREASE THROUGHOUT THE DAY AS NEXT SYSTEM APPROACHES. * TUESDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE. NEXT SHORT WAVE WILL QUICKLY DIVE THROUGH THE FLOW FROM CANADA AND MOVE JUST SOUTH OF SOUTHERN NEW ENGLAND. THE EC IS STILL MORE AMPLIFIED/STRONGER WITH THIS SYSTEM CUTTING OFF THE 850 MB LOW COMPARED TO THE GFS WHICH KEEPS AN OPEN WAVE. THIS HAS ALLOWED FOR PRECIP TO BE CLOSER TO SNE WHILE THE GFS PUSHES EVEN FARTHER SOUTH IMPACTING THE MID-ATLANTIC. OVERALL BELIEVE THAT LOCATIONS ALONG AND SOUTH OF THE PIKE HAVE THE BEST CHANCE TO SEE PRECIP. MODELS ARE SIMILAR ON THE TIMING BRINGING PRECIP IN OVERNIGHT AND PUSHING OUT BY LATE WED MORNING. THIS WILL ALLOW FOR TEMPS TO BE COOL ENOUGH FOR SNOW SHOWERS. WILL NEED TO CONTINUE TO WATCH THE TRENDS WITH THIS SYSTEM SINCE IT COULD PRODUCE A QUICK 1-2 INCHES OF SNOW ACROSS THE AREA. * WEDNESDAY NIGHT INTO FRIDAY...LOW CONFIDENCE IN TIMING. MODERATE CONFIDENCE IN PRECIP OCCURRING. WEAK RIDGE WILL FOLLOW BEHIND THE SYSTEM BEFORE NEXT LOW PRESSURE IMPACT SOUTHERN NEW ENGLAND EITHER THURSDAY OR FRIDAY. EC IS LESS AMPLIFIED AND MORE PROGRESSIVE COMPARED TO THE GFS. STILL PLENTY OF TIME TO WATCH THIS SYSTEM AS WELL. BECAUSE OF THE MODEL DISCREPANCIES HAVE A LOW CONFIDENCE ON TIMING...BUT BOTH DETERMINISTIC AND ENSEMBLE GUIDANCE POINT TOWARDS WET WEATHER THURSDAY INTO FRIDAY. LASTLY TEMPS MAY TURN MORE SPRING-LIKE BY THURS/FRIDAY AHEAD OF NEXT SYSTEM. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/...
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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 THROUGH SUNDAY NIGHT TONIGHT... MVFR CIGS AND IFR VSBYS IN LIGHT SNOW WILL CONTINUE THIS EVENING...SLOWLY IMPROVING TO VFR FROM NW TO SE OVERNIGHT. LOCAL IFR CIGS MAINLY EASTERN MA. LIGHT SNOW MAY NOT TOTALLY END UNTIL NEAR DAYBREAK ALONG THE RI COAST AND SE COASTAL MA. SUNDAY...VFR. HOWEVER MVFR CIGS MAY LINGER NEAR THE CAPE AND ISLANDS UNTIL MID OR LATE MORNING. SUNDAY NIGHT...VFR. INCREASING MID CLOUDINESS THEN MVFR CIGS POSSIBLE LATE IN WESTERN MA AND NORTHERN CT TERMINALS. CHANCE OF A SNOW SHOWER TOWARD DAYBREAK WESTERN MA AND NORTHERN CT. KBOS TAF...MODERATE CONFIDENCE IN TAF TONIGHT. HIGH CONFIDENCE SUNDAY AND SUNDAY NIGHT. KBDL TAF...MODERATE CONFIDENCE IN TAF TONIGHT. HIGH CONFIDENCE SUNDAY AND SUNDAY NIGHT. OUTLOOK...MONDAY THROUGH WEDNESDAY...HIGH CONFIDENCE. MONDAY...VFR DROPPING TO POSSIBLE MVFR IN SCT RAIN SHOWERS AS WEAK COLD FRONT MOVES THROUGH. GUSTY WESTERLY WINDS BEHIND THE FRONT NEAR 20-25 KTS. TUESDAY INTO WEDNESDAY...VFR FOR MOST OF THE PERIOD. MAY SEE MVFR SOUTH OF PIKE IN QUICK MOVING RAIN/SNOW 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...TONIGHT THROUGH SUNDAY NIGHT... MODERATE CONFIDENCE TONIGHT. HIGH CONFIDENCE SUNDAY AND SUNDAY NIGHT. SMALL CRAFT ADVISORIES REMAIN POSTED FOR MOST WATERS. SEAS WILL CONTINUE ON THE ROUGH SIDE...FROM 5 TO 8 FEET ON ALL EXPOSED WATERS AND 1 TO 4 FEET CLOSER TO SHORE. NORTHERLY WIND GUSTS TO 20-25 KNOTS THIS EVENING MAY DIMINISH BRIEFLY AND THEN PICK UP AGAIN AFTER MIDNIGHT AS THE GRADIENT INCREASES BETWEEN LOW PRESSURE WELL OFFSHORE AND HIGH PRESSURE BUILDING IN FROM THE OHIO VALLEY. HIGH PRESSURE BUILDS OVER THE WATERS SUNDAY. WINDS WILL BE DIMINISHING AND SEAS WILL SLOWLY BE SUBSIDING. LINGERING 5 FOOT SEAS ON THE OUTER WATERS DURING THE AFTERNOON. SMALL CRAFT ADVISORIES ARE FORECAST TO BE NO LONGER NEEDED EARLY SUNDAY NIGHT...BUT IT IS POSSIBLE THAT THEY WILL NEED TO BE HOISTED AGAIN LATE SUNDAY NIGHT FOR A PORTION OF THE EASTERN MA OUTER WATERS. SOUTHWEST WINDS AHEAD OF AN APPROACHING COLD FRONT MAY GUST TO 20 TO 25 KT TOWARD DAYBREAK AND SEAS MAY CORRESPONDINGLY INCREASE TO NEAR 5 FT...ESPECIALLY OVER THE WATERS EAST OF CAPE ANN. OUTLOOK...MONDAY THROUGH WEDNESDAY... MODERATE CONFIDENCE INTO WEDNESDAY. MONDAY...APPROACHING COLD FRONT WILL INCREASE SEAS. SCA MAY BE NEEDED. TUESDAY...WEAK LULL IN BETWEEN SYSTEMS HOWEVER WINDS WILL BE GUSTY ON THE BACKSIDE OF THE FRONT REACHING NEAR 30KTS. THIS WILL KEEP SEAS UP ABOVE SCA. TUESDAY NIGHT INTO WEDNESDAY...QUICK MOVING SYSTEM WILL MOVE OVER SOUTHERN WATERS. THIS WILL KEEP BOTH SEAS AND WINDS ABOVE SCA ON TUESDAY NIGHT. HIGH PRESSURE WILL FOLLOW ON WED ALLOWING FOR SEAS AND WINDS TO RELAX.
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&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ230- 232>234. SMALL CRAFT ADVISORY UNTIL 3 PM EDT SUNDAY FOR ANZ231-235-237- 251. SMALL CRAFT ADVISORY UNTIL 10 PM EDT SUNDAY FOR ANZ250-254>256. && $$ SYNOPSIS...FIELD/DUNTEN NEAR TERM...FIELD SHORT TERM...FIELD LONG TERM...DUNTEN AVIATION...FIELD/DUNTEN MARINE...FIELD/DUNTEN

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