Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 052224 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 524 PM EST THU MAR 5 2015 .SYNOPSIS... SNOW WILL EXIT THE SOUTH COAST LATE THIS AFTERNOON OR EARLY EVENING FOLLOWED BY ARCTIC HIGH PRES TONIGHT AND FRI. THE HIGH MOVES SOUTH OF NEW ENGLAND THIS WEEKEND ALLOWING TEMPERATURES TO MODERATE. TWO WEAK FRONTS MAY BRING A PERIOD OF SNOW SHOWERS OR FLURRIES...FIRST SAT NIGHT AND AGAIN SUN NIGHT INTO MON MORNING. NEXT WEEK MAINLY DRY WEATHER PREVAILS ALONG WITH TEMPS WARMING TO NEAR NORMAL. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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*** WINTER STORM WARNING REMAIN IN EFFECT THIS EVENING FOR THE SOUTH COASTS OF MASSACHUSETTS AND RHODE ISLAND AS WELL AS THE ISLANDS *** 530 PM UPDATE... REGIONAL RADARS INDICATE BACK EDGE OF SNOW SHIELD BLOSSOMING SOMEWHAT ACROSS NYC AREA/LONG ISLAND AND COASTAL CT. THIS IS IN RESPONSE TO MID LEVEL TROUGH STILL WEST OF THE REGION AND ITS ASSOCIATED SW FLOW ALOFT ACROSS THE REGION. THIS MOIST SW FLOW ALOFT IS OVER-RUNNING A COLD DOME ACROSS THE AREA. ADDITIONAL LIFT BEING PROVIDED BY STRONG UPPER LEVEL JET STREAK OF 200KT ACROSS NORTHERN NEW ENGLAND INTO THE MARITIMES...WITH RRQ OVER SOUTHERN NEW ENGLAND. GIVEN MID LEVEL TROUGH AXIS DOESN`T MOVE OFFSHORE TIL AFTER 00Z...WILL EXTEND WINTER STORM WARNING FOR CAPE COD AND THE ISLANDS TIL 10 PM...7PM ELSEWHERE. ONCE MID LEVEL TROUGH MOVES OFFSHORE ARCTIC AIRMASS WITH DEW PTS BELOW ZERO OVER NORTHERN NEW ENGLAND AND NY STATE WILL SURGE SOUTHWARD INTO OUR REGION. THIS COMBINED WITH A REPLENISHED SNOWCOVER WILL RESULT IN A FRIGID NIGHT. EARLIER DISCUSSION BELOW. ==================================================================== HEAVY SNOW BAND ALONG THE SOUTH COAST...CAPE...AND ISLANDS AT THIS TIME. EXPECT SNOW TO CONTINUE ALONG THE SOUTH COAST FOR ANOTHER HOUR OR TWO AS THIS BAND PUSHES OFF TO THE SOUTHEAST. SNOW MAY LAST FOR AN ADDITIONAL HOUR /ROUGHLY THROUGH 7 PM/ ON THE CAPE AND ISLANDS. DRY AIR IS MORE AGGRESSIVELY PUSHING SOUTHWESTWARD INTO NORTHERN RHODE ISLAND AND SOUTHEASTERN MASSACHUSETTS. DEWPOINTS HAVE FALLEN INTO THE SINGLE DIGITS NORTH AND WEST OF A WESTERLY RHODE ISLAND TO TAUNTON TO MARSHFIELD MASSACHUSETTS LINE. SOUTH AND EAST OF THIS LINE...DEWPOINTS ARE STILL IN THE LOW 20S. TONIGHT...SNOW WILL COME TO AN END AS DRIER AIR CONTINUES TO WORK ITS WAY SOUTHWESTWARD. BEHIND THIS SNOW...DEWPOINTS WILL CONTINUE TO PLUNGE INTO THE SINGLE DIGITS. TEMPERATURES WILL CRATER THROUGH THE NIGHT AS SKIES CLEAR AND WINDS BECOME CALM. THIS WILL RESULT IN EXCELLENT RADIATIONAL COOLING WITH TEMPERATURES DROPPING INTO THE SINGLE DIGITS BOTH ABOVE AND BELOW ZERO ASIDE FROM THE CAPE AND ISLANDS WHERE TEMPS WILL BE IN THE TEENS.
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&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... FRIDAY AND FRIDAY NIGHT...HIGH PRESSURE BUILDS INTO THE AREA FROM THE MIDWEST AND THEN SLIDES SOUTH OF SOUTHERN NEW ENGLAND FRIDAY NIGHT. QUIET BUT CHILLY WEATHER EXPECTED DURING THIS TIME WITH TEMPERATURES ROUGHLY 20 DEGREES BELOW NORMAL FOR EARLY MARCH. && .LONG TERM /SATURDAY THROUGH THURSDAY/... HIGHLIGHTS... * TEMPERATURES...NOT AS COLD THIS WEEKEND AND MODERATING TO NEAR NORMAL NEXT WEEK * PRECIPITATION...RELATIVELY DRY WITH ANY PRECIP EVENTS VERY MINOR GOOD MODEL AGREEMENT ON THE LARGE SCALE FLOW WITH WEST COAST AND EASTERN PACIFIC RIDGE HOLDING ON THRU THE WEEKEND INTO EARLY NEXT WEEK. THIS RESULTS IN A CONTINUATION OF A DOWNSTREAM LONG WAVE TROUGH AND ASSOCIATED COLDER THAN NORMAL TEMPS OVER THE GREAT LAKES INTO NEW ENGLAND. HOWEVER THERE IS A GOOD AGREEMENT AMONG THE 12Z GEFS AND 00Z EPS ENSEMBLES ALONG WITH 12Z DETERMINISTIC GUID THAT THIS RIDGE MOVES INTO THE CENTRAL US MIDDLE OF NEXT WEEK...YIELDING MEAN MID LEVEL TROUGH AXIS TO MOVE EAST OF NEW ENGLAND. THIS RESULTS IN DEAMPLIFICATION OF THE PATTERN AND TEMPS MODERATING TO POSSIBLY SEASONABLE LEVELS /HIGHS IN THE 40S AND LOWS IN THE 20S/ NEXT WEEK. AS FOR PRECIP...NORTHERN BRANCH REMAINS THE DOMINANT AIR STREAM ACROSS NEW ENGLAND THIS WEEKEND INTO EARLY NEXT WEEK. THIS KEEPS MID LEVEL CONFLUENT ZONE SOUTH OF NEW ENGLAND PRECLUDING STREAMS FROM MERGING/PHASING AT THIS LONGITUDE...RESULTING IN A FAIRLY DRY PATTERN. HOWEVER THE NORTHERN STREAM WILL DELIVER A FEW MOISTURE STARVED SHORT WAVES/FRONTS TO ZIP ACROSS THE AREA DURING THIS TIME. THE FIRST SHORT WAVE AND RISK OF LIGHT SNOW/FLURRIES ARRIVES SAT NIGHT FOLLOWED BY ANOTHER TRAILING IMPULSE SUN NIGHT INTO EARLY MONDAY. OTHERWISE DRY WEATHER PREVAILS MUCH OF NEXT WEEK. && .AVIATION /22Z THURSDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY NIGHT/...MODERATE CONFIDENCE TODAY. HIGH CONFIDENCE TONIGHT THROUGH FRIDAY NIGHT. IFR AND MVFR CONDITIONS IN LIGHT TO OCCASIONALLY MODERATE SNOW ACROSS SOUTHERN PORTIONS OF THE REGION...MAINLY SOUTH OF A LINE FROM IJD-SFZ-TAN-GHG. THESE CONDITIONS PERSIST MOST OF THE DAY. VFR TO OCCASIONAL MVFR CIGS NORTH OF THAT LINE. SKIES BEGIN TO CLEAR FROM NW TO SE LATE THIS AFTERNOON...REACHING CAPE COD AND NANTUCKET LATE TONIGHT. CLEAR SKIES EXPECTED LATER TONIGHT THROUGH FRIDAY NIGHT. KBOS TAF...HIGH CONFIDENCE. KBDL TAF...HIGH CONFIDENCE. OUTLOOK...SATURDAY THROUGH TUESDAY...MODERATE CONFIDENCE. MAINLY VFR WITH LIGHT TO MODEST WINDS. BRIEF MVFR CIGS/VSBYS POSSIBLE SATURDAY NIGHT AND AGAIN SUN NIGHT IN WIDELY SCATTERED SNOW SHOWERS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY/...MODERATE CONFIDENCE. HIGH CONFIDENCE. WINDS AND SEAS WILL CONTINUE TO DIMINISH AS HIGH PRESSURE BUILDS OVER THE WATERS FRIDAY. SMALL CRAFT ADVISORIES CURRENTLY IN PLACE WILL NO LONGER BE NEEDED BY FRIDAY MORNING. OUTLOOK...SATURDAY THROUGH TUESDAY...MODERATE CONFIDENCE. SATURDAY...MODEST WSW WIND OF 20-25 KT AHEAD OF COLD FRONT. VSBY MAY LOWER BRIEFLY IN SCATTERED SNOW SHOWERS SAT NIGHT. SUNDAY...MODEST WNW WINDS BEHIND THE FRONT. THEN WINDS BECOME SW AT NIGHT AHEAD OF NEXT FRONT. VSBY MAY LOWER BRIEFLY IN SCATTERED SNOW SHOWERS SUN NIGHT. MON...SW WINDS IN THE AM WITH SCATTERED SNOW SHOWERS...THEN WNW IN THE PM BEHIND FRONTAL PASSAGE. TUE...LOOKS TRANQUIL WITH HIGH PRES BUILDING INTO NEW ENGLAND. && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR MAZ020>024. RI...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR RIZ003>008. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ235-237. SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR ANZ250-254>256. FREEZING SPRAY ADVISORY UNTIL 5 AM EST FRIDAY FOR ANZ250-251.
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&& $$ SYNOPSIS...NOCERA/RLG NEAR TERM...NOCERA/RLG SHORT TERM...RLG LONG TERM...NOCERA AVIATION...NOCERA/RLG MARINE...NOCERA/RLG

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