Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 190203 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1003 PM EDT THU SEP 18 2014 .SYNOPSIS... A WEAK...DRY COLD FRONT WILL CROSS THE AREA THIS EVENING. COLD HIGH PRESSURE BUILDS INTO NEW ENGLAND TONIGHT AND FRIDAY. SOME FROST MAY FORM ACROSS PORTIONS OF SOUTHERN NEW HAMPSHIRE LATE TONIGHT. THE HIGH WILL DRIFT OFFSHORE THROUGH THE WEEKEND RESULTING IN A BRIEF RETURN TO MILDER TEMPERATURES. A COLD FRONT MOVES THROUGH EARLY MONDAY...FOLLOWED BY COOLER WEATHER TOWARD THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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10 PM UPDATE... SFC OBS SUGGEST THAT THE WEAKENED COLD FRONT IS CURRENTLY ABOUT 20-30 SM FROM THE S COAST. WINDS HAVE PICKED UP WITH RISING PRES ACROSS MUCH OF THE NRN AND E HALF OF THE REGION...SUSTAINING AT ABOUT 10 KT. HOWEVER...DO CONTINUE TO NOTE THAT SKIES HAVE ALREADY CLEARED ACROSS THE NW AND CONTINUES TO DISSIPATE EVEN ACROSS SRN AND ERN PORTIONS OF THE FORECAST AREA AND SOME DEEPER VALLEYS IN NY/VT ARE ALREADY SHOWING CALM CONDITIONS. LATEST MESOSCALE GUIDANCE SUPPORTS THIS DECOUPLING CONTINUING TO EXPEND TOWARD THE SE...SO PORTIONS OF SRN NH AND NW MA MAY STILL DECOUPLE FULLY LATER ON. THEREFORE...FEEL THAT CURRENT TIMING AND PLACEMENT OF THE FROST ADVISORY LOOK TO BE REASONABLE...AND HAVE ADJUSTED TEMPS DWPTS TO BETTER MATCH THIS THINKING. OTHERWISE...UPDATED SKIES TO REFLECT TRENDS IN LEFTOVER LOWER CLOUDINESS FROM THE FRONTAL PASSAGE. PREVIOUS DISCUSSION.. TONIGHT...HIGH PRES BRING PUSH OF COLD AIR ACROSS THE REGION... THOUGH SHORT RANGE MODELS INDICATING CORE OF COLDEST H85 AIR WILL REMAIN N OF THE REGION. EXPECT SKIES TO CLEAR FROM N-S OVERNIGHT...FIRST ACROSS S NH BY AROUND MIDNIGHT OR 1 AM. SOME CLOUDS MAY LINGER ALONG THE S COAST THROUGH THE NIGHT. NOTING PRES SURGE BEHIND THE FRONT ON THE MODEL WIND FIELDS. EXPECT N-NE WINDS TO INCREASE QUICKLY EARLY TONIGHT ACROSS THE WATERS E OF CAPE ANN THEN WORKING DOWN THE COAST. COULD SEE GUSTS UP TO 20-25 KT ALONG THE IMMEDIATE E COAST FROM ABOUT BOSTON SOUTHWARD TO THE CAPE AND ISLANDS THROUGH THE NIGHT. FURTHER INLAND...WINDS WILL DROP OFF TO LIGHT/VRBL OR CALM ESPECIALLY ACROSS THE NORMALLY PRONE AREAS NEAR THE CT VALLEY AND CHESHIRE COUNTY. WITH THE LIGHT WINDS AND CLEARING SKIES...THIS WILL ALLOW FOR A PERIOD OF RADIATIONAL COOLING AFTER MIDNIGHT. EXPECT THE BEST CHANCE FOR VERY CHILLY TEMPS ACROSS NORTHERN CHESHIRE AND NW HILLSBOROUGH COUNTIES...AND COULD SEE SOME POCKETS OF FROST. HAVE ISSUED FROST ADVISORY FOR THESE AREAS. OVERNIGHT LOWS WILL DROP TO THE LOWER-MID 30S IN THE FROST ADVISORY AREA...RANGING TO THE LOWER-MID 50S ALONG THE IMMEDIATE E COAST.
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&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... FRIDAY...THE CENTER OF LARGE HIGH PRES BUILDS ACROSS NEW ENGLAND DURING THE DAY. WILL SEE LEFTOVER GUSTY WINDS ALONG THE E COAST FRIDAY MORNING THEN...AS HIGH PRES BUILDS IN...WINDS WILL DIMINISH. EXPECT MAINLY CLEAR SKIES BUT TEMPS WILL BE MUCH COOLER. HIGHS WILL ONLY BE IN THE MID 50S IN THE NORMALLY COLDER INLAND LOCALES TO THE MID 60S IN THE LOWER CT VALLEY. FRIDAY NIGHT...HIGH PRES SLOWLY PUSHES OFFSHORE SO...WHILE SKIES WILL BE MAINLY CLEAR...NOTING THAT THE DEWPTS WILL BEGIN TO RISE AS LIGHT WINDS SHIFT TO S-SE OVERNIGHT. WILL ALSO START TO SEE HIGH CLOUDS PUSH INTO WESTERN AREAS AFTER MIDNIGHT. MAY STILL SEE TEMPS FALL TO THE UPPER 30S IN THE NORMALLY PRONE COOLER SPOTS... THOUGH MOST LOCALES WILL BE IN THE 40S TO LOWER 50S. && .LONG TERM /SATURDAY THROUGH THURSDAY/... OVERVIEW AND MODEL PREFERENCES...THIS PORTION OF THE FORECAST STILL LOOKS LIKE IT WILL BE DEFINED BY A DEVELOPING MID-LEVEL TROUGH ACROSS THE NORTHEAST USA LATE THIS WEEKEND AND EARLY NEXT WEEK. THIS TROUGH LOOKS LIKE IT MOVES INTO THE MARITIMES TOWARD THE MIDDLE OF NEXT WEEK. OVERALL...THERE IS DECENT AGREEMENT AMONG THE 18/12Z GUIDANCE SUITE THROUGH THE MIDDLE OF NEXT WEEK. AFTER THEN...TIMING DIFFERENCES BECOME MORE PREVALENT...BUT SHOULD NOT HAVE A MAJOR IMPACT ON THE SENSIBLE WEATHER. WILL CONTINUE TO FAVOR A CONSENSUS BLEND TO MINIMIZE THESE DETAIL DIFFERENCES. SATURDAY AND SATURDAY NIGHT...A LARGE HIGH PRESSURE OVER THE NORTH ATLANTIC NEAR NOVA SCOTIA CONTINUES TO MOVE FARTHER OUT TO SEA. THIS LEAVES SOUTHERN NEW ENGLAND IN A PROGRESSIVELY WEAKER RIDGE AXIS WITH TIME. DRY WEATHER THE MOST LIKELY OUTCOME AS THE AIRMASS REMAINS QUITE DRY. SLIGHTLY BELOW NORMAL HIGH TEMPERATURES EXPECTED SATURDAY...WITH ABOVE NORMAL LOW TEMPERATURES SATURDAY NIGHT AS SOUTHERLY WINDS CONTINUE. SUNDAY INTO MONDAY... THIS PERIOD IS STARTING TO LOOK LIKE A RACE BETWEEN A WEAK COASTAL LOW PRESSURE MOVING NORTH AND A COLD FRONT MOVING EAST. THIS FRONT IS INCREASINGLY LOOKING MOISTURE-STARVED AS IT CROSSES SOUTHERN NEW ENGLAND. THE 18/12Z GFS APPEARS TO BE A WESTERN AND FASTER OUTLIER...WHEN COMPARED TO THE OTHER GUIDANCE SOURCES...WITH ITS HANDLING OF THIS COASTAL LOW PRESSURE. WHILE NOT EXPECTED TO BE A POTENT STORM...IT COULD SUPPLY THE MOISTURE THIS PASSING FRONT WOULD NEED TO PRODUCE MORE SIGNIFICANT RAINFALL. THERE ARE MANY AREAS ACROSS CT...RI AND SOUTHEAST MA WHICH COULD REALLY USE SOME RAINFALL. AT THIS TIME...WILL ONLY MENTION A CHANCE OF SHOWERS WITH RAINFALL TOTALS LESS THAN ONE QUARTER INCH. THERE HAS BEEN A RECENT TREND IN THE GUIDANCE OF BEING TOO AGGRESSIVE WITH RAINFALL AMOUNTS. WILL WAIT UNTIL THE TIMING ISSUES BETWEEN THIS FRONT AND COASTAL LOW CAN BE IRONED OUT. THINKING IT MOST LIKELY THIS COASTAL LOW PASSES BY TOO FAR OFFSHORE TO HAVE MUCH IMPACT. HIGH TEMPERATURES EXPECTED TO BE WELL ABOVE NORMAL SUNDAY...BEFORE RETURNING TO MORE SEASONABLE VALUES BY MONDAY MORNING. TUESDAY INTO THURSDAY... A LARGE HIGH PRESSURE MOVES INTO OUR REGION...PROVIDING PROLONGED DRY WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES. && .AVIATION /02Z FRIDAY 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/...HIGH CONFIDENCE. TONIGHT...VFR. CLEARING SKIES FROM N-S AS FRONT PUSHES OFFSHORE. N-NE WINDS MAY GUST TO 20-25 KT ALONG E COAST FROM BOSTON S TO CAPE COD AND THE ISLANDS OVERNIGHT. FRIDAY-FRIDAY NIGHT...VFR. MAINLY CLEAR SKIES THROUGH EARLY FRI NIGHT...THEN HIGH CLOUDS INCREASE ACROSS WESTERN AREAS. NE WINDS GUSTING TO 20 KT EARLY FRI ACROSS CAPE COD AND THE ISLANDS THEN DIMINISHING. E WINDS 10 KT OR LESS LATE FRI...SHIFTING TO S-SE FRI NIGHT. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SEA BREEZE THROUGH 22Z-23Z. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...SATURDAY THROUGH TUESDAY... SATURDAY INTO SUNDAY MORNING...HIGH CONFIDENCE. MAINLY VFR THROUGH THIS PERIOD. ALTHOUGH SOME PATCHY GROUND FOG IS POSSIBLE BOTH SATURDAY AND SUNDAY MORNINGS AT TYPICALLY PRONE AIRPORTS. WINDS MAINLY S-SW...WITH GUSTS UP TO 20 KT POSSIBLE SUNDAY. SUNDAY AFTERNOON INTO MONDAY...MODERATE CONFIDENCE. A COLD FRONT CROSSES THE REGION DURING THE EARLY MORNING HOURS MONDAY. SCATTERED SHOWERS WITH MVFR/IFR CONDITIONS MAY MOVE THROUGH WITH THIS FRONT. OTHERWISE...IMPROVING BACK TO VFR BY LATE DAY MONDAY. TUESDAY...HIGH CONFIDENCE. VFR. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE. THROUGH 00Z...COLD FRONT CROSSES THE WATERS BY THIS EVENING. EXPECT NW WINDS TO SHIFT TO N-NE. LONG GROUND SWELLS OF 3 TO 4 FT CONTINUE FROM DISTANT HURRICANE EDOUARD. MAY SEE BRIEF SWELLS TO 5 FT ON THE OUTER WATERS S AND E OF CAPE COD AND NANTUCKET WHICH SHOULD SLOWLY SUBSIDE. TONIGHT...WILL SEE PRESSURE SURGE WORKING DOWN FROM THE N ACROSS THE WATERS AS COLDER AIR MOVES ACROSS THE MILDER WATERS. EXPECT N-NE WIND GUSTS UP TO 25-30 KT MAINLY AFTER MIDNIGHT. HAVE RAISED SMALL CRAFT FOR RI SOUND. FRIDAY...NE WINDS REMAIN GUSTY FRI MORNING...THEN DIMINISH AS HIGH PRES BUILDS N OF THE WATERS. SEAS BUILD UP TO 6-7 FT ON THE OUTER WATERS. SMALL CRAFTS CONTINUE...THOUGH CONDITIONS SHOULD IMPROVE ON THE NEAR SHORE SOUNDS AND BAYS BY EARLY AFTERNOON. FRIDAY NIGHT...LIGHT E WINDS IN PLACE. LEFTOVER SEAS ON THE OUTER WATERS SHOULD SUBSIDE BELOW SMALL CRAFT CRITERIA BY AROUND MIDNIGHT. OUTLOOK...SATURDAY THROUGH TUESDAY...MODERATE CONFIDENCE. SATURDAY-SUNDAY...WINDS SHIFT TO SOUTH WITH DAYTIME GUSTS UP TO 20 KNOTS NEARSHORE. SEAS WILL REMAIN 2-4 FEET. A COLD FRONT APPROACHES LATE SUNDAY WITH A CHANCE OF SHOWERS SUNDAY NIGHT. MONDAY...A COLD FRONT CROSSES THE WATERS EARLY IN THE DAY. WEST WINDS BEHIND THIS FRONT WILL REMAIN LESS THAN 20 KNOTS. SEAS WILL BUILD TO 5-7 FEET ON THE OUTER AND EXPOSED WATERS...AS A SOUTH SWELL INCREASES TO 3-5 FEET. SMALL CRAFT ADVISORIES MAY BE NEEDED. TUESDAY...NORTHWEST WINDS AND SUBSIDING SEAS EXPECTED AS A HIGH PRESSURE MOVES OVER THE WATERS. SEAS WILL TAKE LONGEST TO DIMINISH ACROSS THE OUTER COASTAL WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. NH...FROST ADVISORY FROM 1 AM TO 8 AM EDT FRIDAY FOR NHZ011-015. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 2 AM TO 2 PM EDT FRIDAY FOR ANZ232>235-237. SMALL CRAFT ADVISORY FROM 2 AM TO 5 PM EDT FRIDAY FOR ANZ231- 251. SMALL CRAFT ADVISORY UNTIL 8 PM EDT FRIDAY FOR ANZ250. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT FRIDAY NIGHT FOR ANZ254-255. SMALL CRAFT ADVISORY FROM 2 AM TO 10 PM EDT FRIDAY FOR ANZ256.
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&& $$ SYNOPSIS...BELK/EVT NEAR TERM...DOODY/EVT SHORT TERM...EVT LONG TERM...BELK AVIATION...BELK/EVT MARINE...BELK/EVT

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