Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 282044 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 444 PM EDT SAT MAR 28 2015 .SYNOPSIS... 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. A FAST MOVING LOW PRESSURE SOUTH OF NEW ENGLAND COULD BRING MORE LIGHT RAIN AND/OR SNOW SHOWERS TUESDAY NIGHT INTO WEDNESDAY. A MORE SIGNIFICANT STORM MAY APPROACH LATE NEXT WEEK. && .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 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 MONDAY...BRINGING SCT SHOWERS * MODERATING SPRING-LIKE TEMPERATURES INTO NEXT WEEK * ALBERTA CLIPPER PASSES BY TO THE SOUTH TUESDAY NIGHT INTO WEDNESDAY * INCREASING CHANCES FOR PRECIPITATION SOMETIME DURING EASTER WEEKEND OVERVIEW... AN ACTIVE PATTERN APPEARS TO BE SETTING UP OVER SOUTHERN NEW ENGLAND NEXT WEEK. ANOMALOUSLY DEEP MID LEVEL TROUGH SLOWLY MOVES OUT TOWARD MID WEEK...LEAVING BEHIND A SIGNIFICANTLY LESS AMPLIFIED FLOW. THIS IS LEADING TO GREATER GREATER SPREAD IN THE MODEL SOLUTIONS FOR LATE NEXT WEEK AS IT IS VERY TOUGH TO CONSISTENTLY TIME INDIVIDUAL SHORTWAVES WITHIN A RELATIVELY FAST MID-LEVEL FLOW. SINCE THE MODELS GENERALLY AGREE ON THE OVERALL SYNOPTIC PATTERN...WILL FOLLOW A CONSENSUS BLEND APPROACH TO SMOOTH OVER THESE FINER-SCALE DIFFERENCES. DETAILS... * MONDAY...HIGH CONFIDENCE. NEXT UPPER LEVEL SHORTWAVE WILL QUICKLY MOVE THROUGH NW FLOW ALOFT MONDAY. GUIDANCE SEEMS TO BE IN BETTER AGREEMENT WITH THIS SYSTEM...BRINGING PRECIPITATION EARLY MONDAY MORNING. SURFACE LOW ACROSS THE GREAT LAKES WILL PASS BY TO OUR NORTH...SWINGING ITS ASSOCIATED COLD FRONT THROUGH SOUTHERN NEW ENGLAND. TEMPERATURES AT THE ONSET LOOK TO BE LOW ENOUGH TO SUPPORT SNOW SHOWERS. THOUGH RAIN SHOWERS WILL QUICKLY BECOME MORE PREDOMINANT PRIOR TO FRONTAL PASSAGE. MOISTURE IS MARGINAL...SO COVERAGE MAY BE MORE SCATTERED ALONG THE FRONT. EXPECTING VERY MINOR ACCUMULATIONS WITHIN ANY SNOW SHOWERS. BEHIND THIS FRONT...WESTERLY WINDS WILL BE ON THE INCREASE AND GUSTING TO 25-30 MPH. * TUESDAY INTO WEDNESDAY...MODERATE CONFIDENCE. NEXT SHORTWAVE WILL QUICKLY MOVE FROM CANADA JUST SOUTH OF SOUTHERN NEW ENGLAND. AS IT DOES...WE EXPECT TO SEE A CLIPPER-LIKE LOW PRESSURE MOVING FROM THE MID ATLANTIC COAST AND STAYING JUST SOUTH OF NEW ENGLAND. LOCATIONS ALONG AND SOUTH OF THE MASS PIKE HAVE THE GREATEST RISK FOR PRECIPITATION. MODELS ARE SIMILAR ON THE TIMING BRINGING PRECIPITATION IN LATE TUESDAY AFTERNOON...AND PUSHING IT OUT BY LATE WEDNESDAY MORNING. THIS WILL ALLOW FOR TEMPERATURES TO BE LOW ENOUGH FOR SOME LIGHT SNOW...BUT MOSTLY EXPECTING RAINFALL AT THIS TIME. WILL NEED TO CONTINUE TO WATCH THE TRENDS WITH THIS SYSTEM...SINCE IT COULD PRODUCE A QUICK 1-2 INCHES OF SNOW SOUTH OF THE MASS PIKE. * THURSDAY INTO SATURDAY...LOW CONFIDENCE IN TIMING. MODERATE CONFIDENCE IN PRECIPITATION OCCURRING. WEAK RIDGE WILL BRIEFLY TAKE OVER WEDNESDAY NIGHT. THE NEXT LOW PRESSURE TO IMPACT SOUTHERN NEW ENGLAND SHOULD SWING A COLD FRONT THROUGH OUR REGION EITHER THURSDAY OR FRIDAY. A MORE SIGNIFICANT LOW PRESSURE SHOULD ARRIVE SOMETIME FRIDAY NIGHT INTO SATURDAY. TEMPERATURES AT THIS POINT LOOK TO BE HIGH ENOUGH FOR MOSTLY RAIN WITH THIS PARTICULAR STORM. && .AVIATION /21Z SATURDAY THROUGH THURSDAY/... 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 THURSDAY...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. THURSDAY...VFR MOST OF THE DAY. && .MARINE... 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 THURSDAY...HIGH CONFIDENCE. MONDAY INTO TUESDAY...APPROACHING COLD FRONT WILL INCREASE WINDS AND SEAS IN RESPONSE. WINDS SHOULD REMAIN GUSTY ON THE BACKSIDE OF THIS FRONT EARLY TUESDAY. THIS WILL ALLOW FOR SMALL CRAFT ADVISORY TO CONTINUE ACROSS PORTIONS OF THE OUTER COASTAL WATERS. TUESDAY NIGHT INTO WEDNESDAY...QUICK-MOVING SYSTEM WILL MOVE OVER SOUTHERN WATERS. THIS WILL KEEP BOTH SEAS AND WINDS ABOVE SMALL CRAFT ADVISORY LEVELS TUESDAY NIGHT. HIGH PRESSURE WILL FOLLOW ON WED ALLOWING FOR SEAS AND WINDS TO GRADUALLY RELAX. THURSDAY...WEAK HIGH PRESSURE SHOULD BE OVER THE WATERS...WITH RELATIVELY TRANQUIL CONDITIONS. && .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...BELK/GAF NEAR TERM...GAF SHORT TERM...GAF LONG TERM...BELK AVIATION...BELK/GAF MARINE...BELK/GAF

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