Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 271947 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 347 PM EDT MON OCT 27 2014 .SYNOPSIS...
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MILD TEMPERATURES WILL CONTINUE INTO TOMORROW AS WELL AS THE DRY WEATHER. A SWEEPING COLD FRONT WITH SHOWERS LIKELY EXPECTED WEDNESDAY INTO WEDNESDAY NIGHT. COOL AND DRY FOR THURSDAY. A SIGNIFICANT STORM IS LOOKING MORE LIKELY BEGINNING FRIDAY INTO THE WEEKEND. UNSEASONABLY COOLER WEATHER IS ANTICIPATED FOR EARLY NEXT WEEK.
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&& .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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4 PM UPDATE... OVERALL TREND IN THE FORECAST REMAINS ON TRACK. DIURNAL CU HAS ALREADY STARTED TO DISSIPATE LATE THIS AFTERNOON...WHICH WILL LEAD TO MOSTLY SKIES TONIGHT. WIND SPEEDS HAVE BEGUN TO SLOW DOWN AS SURFACE HIGH PRESSURE NOSES INTO THE REGION. OTHERWISE MADE SOME MINOR TWEAKS TO THE FORECAST TO ACCOUNT FOR CURRENT TRENDS. PREVIOUS DISCUSSION... UPPER LEVEL TROUGH AND ASSOCIATED SHORTWAVES HAS MOVED OFFSHORE LATE THIS MORNING/EARLY THIS AFTERNOON. CURRENTLY A MID-LEVEL RIDGE IS BEGINNING TO PUSH ACROSS THE EASTERN GREAT LAKES AND TOWARDS SOUTHERN NEW ENGLAND. BECAUSE WE ARE IN BETWEEN SYSTEMS...THE PRESSURE GRADIENT IS STILL TIGHT SO ANTICIPATE 20 MPH WNW GUSTS TO LAST FOR ONLY A FEW MORE HOURS...ESP SINCE HEIGHTS ARE RISING. A GOOD AMOUNT OF MIXING IS STILL OCCURRING SO TEMPS HAVE WARMED A FEW DEGREES MORE THAN ORIGINALLY...AND HAVE REFLECTED THIS IN THE AFTERNOON UPDATE. ANTICIPATE PLACES TO WARM INTO THE UPPER 50S TO LOW 60S. HERE AT TAUNTON...WE ARE CURRENTLY AT 63F...WHICH IS SEVERAL DEGREES ABOVE NORMAL. DIURNAL CU HAS DEVELOP ACROSS A PORTION OF THE AREA THIS AFTERNOON AND WILL CONTINUE UNTIL SUNSET...WHEN WE LOSE THE DIURNAL HEATING. OUT WEST...HIGH LEVEL CLOUDS ARE STARTING TO STREAM INTO UPSTATE NY AND THIS MAY PLAY ON THE TEMPERATURE FORECAST FOR TONIGHT. TONIGHT... HIGH PRESSURE WILL CONTINUE TO NOSE INTO THE REGION OVERNIGHT... RESULTING IN DRY WEATHER...LIGHT WINDS AND MOSTLY CLEAR SKIES WHICH ARE EXCELLENT RADIATIONAL COOLING CONDITIONS. THE RELATIVELY DRY AIRMASS IN PLACE SHOULD ALLOW LOW TEMPS TO FALL INTO THE 30S ACROSS THE OUTLYING LOCATIONS...TO THE LOWER TO MIDDLE 40S IN THE URBAN CENTERS OF DOWNTOWN PROVIDENCE/BOSTON. ONLY CAVEAT IS THE MID LEVEL CLOUDS WHICH WILL MOVE OVERHEAD IN ASSOCIATED WITH THE WARM FRONT. THIS MAY LIMIT THE AMOUNT OF RADIATIONAL COOLING OVERNIGHT. BECAUSE OF THIS POTENTIAL AND THE FACT THAT TEMPS ALOFT WARM THROUGH THE NIGHT...HAVE BROUGHT OVERNIGHT TEMPS UP A FEW DEGREES.
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&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
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TOMORROW AND TOMORROW NIGHT... WARM FRONT WILL MOVE ACROSS THE REGION OVERNIGHT PUTTING SOUTHERN NEW ENGLAND INTO A WARM SECTOR TOMORROW. IN FACT 925 MB TEMPS WILL START OUT AT +10C AND WARM TO +18C THROUGHOUT THE DAY. MODELS SHOW GOOD LAPSE RATES SO ANTICIPATE MORE MIXING THEN WHAT CURRENT BUFKIT SOUNDINGS SHOW. THIS WILL YIELD TO GUSTY WINDS AROUND 25 MPH AND TEMPS WARMING INTO THE MID TO UPPER 60S. CANNOT RULE OUT THE POTENTIAL FOR A FEW 70S IN SOME LOCATIONS. A FEW CLOUDS WILL STREAM BY AND EVEN SOME DIURNAL CU MAY DEVELOP BUT OVERALL EXPECT A GOOD AMOUNT OF SUNSHINE FOR THE DAY. 925 MB TEMPS WILL CONTINUE TO WARM OVERNIGHT TO +20C AND WITH AN APPROACHING COLD FRONT TO THE WEST...PRESSURE GRADIENT WILL TIGHTEN UP. OVERNIGHT GUSTS WILL CONTINUE TO AROUND 15-20 MPH AND WITH CLOUDS BEGINNING TO MOVE IN FROM THE NORTHWEST...TEMPS WILL REMAIN STEADY THROUGH THE NIGHT. IN FACT...SOME SITES MAY NOT EVEN DROP BELOW 60F. COLD FRONT WILL BE APPROACHING FROM THE WEST DURING THE OVERNIGHT HOURS. RIGHT NOW EXPECT MOST OF THE REGION TO STAY DRY UNTIL WED MORNING...YET CANNOT RULE OUT A SPOT SHOWER OUT WEST AHEAD OF THE FRONT NEAR DAYBREAK.
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&& .LONG TERM /WEDNESDAY THROUGH MONDAY/...
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*/ HIGHLIGHTS... - COLD FRONT WITH SHOWERS WEDNESDAY INTO WEDNESDAY NIGHT - COOL AND DRY FOR THURSDAY - SIGNIFICANT STORM SYSTEM APPEARING LIKELY FRIDAY INTO THE WEEKEND - APPEARING UNSEASONABLY COOLER FOR EARLY NEXT WEEK */ OVERVIEW AND MODEL CONSENSUS... CONSIDERING DETERMINISTIC/ENSEMBLE MEMBER SOLUTIONS...THERE IS VERY HIGH CONFIDENCE WITH REGARDS TO THE FORECAST WEDNESDAY-THURSDAY. THEREAFTER...CONFIDENCE DROPS AS TO POTENTIAL IMPACTS ASSOCIATED WITH A SIGNIFICANT WEEKEND STORM SYSTEM WHICH IS APPEARING MORE LIKELY. WILL TRY TO BE SUCCINCT WITH THE DISCUSSION BELOW...NOTING THE SIGNIFICANT POINTS AS TO THE FORECAST. TO BEGIN WILL GO WITH A MODEL CONSENSUS BLEND FOR MIDWEEK. SWEEPING COLD FRONT THE FOCUS OF SHOWERS WEDNESDAY-WEDNESDAY NIGHT. MODEST H85 SW-MOIST FETCH +2 STANDARD DEVIATIONS /SD/ ADVECTING PWATS > AN INCH /+1-2 SD/. F-GEN FORCING AHEAD OF THE LEAD IMPULSE BENEATH THE RRQ OF THE UPPER-LEVEL JET SHOULD YIELD DEEP LAYER LIFT. SO WITH REGARDS TO POTENTIAL THREATS/IMPACTS: WITHIN THE ANTICIPATED BAND OF SHOWERS EXPECT SOME EMBEDDED HEAVY DOWNPOURS POTENTIALLY MIXING DOWN GUSTY SW-WINDS AROUND 40 MPH /MAINLY WEDNESDAY/. OTHERWISE BLUSTERY WITH SW-GUSTS UP TO 30 MPH ESPECIALLY ALONG THE S/SE-SHORE. A RUMBLE OF THUNDER ACROSS FAR SE-WATERS...AND FINALLY PERHAPS SOME NUISANCE FLOODING IN URBAN AREAS WITH LEAF-CLOGGED DRAINS. WILL SEE COOLER AND DRIER CONDITIONS UNDER HIGH PRESSURE FOR THURSDAY UNDER BREEZY W/NW FLOW RELAXING THROUGH THE DAY INTO EVENING. BELOW FREEZING CONDITIONS ANTICIPATED FRIDAY MORNING. AS TO FRIDAY THROUGH THE WEEKEND...NO ONE PARTICULAR SOLUTION IS PREFERRED. CONCEDE TO A BLEND OF ENSEMBLE MEANS. WHAT APPEARS LIKELY IS THE INTERACTION OF N- AND S-STREAM LOW PRESSURE CENTERS...WITH THE POSSIBILITY OF PHASING. ATTRIBUTABLE ENERGY PASSING IN VICINITY OF S NEW ENGLAND ACT TO DEEPEN THE H5 N-STREAM OPEN-WAVE TROUGH INTO A CLOSED LOW INVOKING A POSSIBLE OCCLUSION STRETCHING FROM AROUND HALIFAX CANADA WESTWARD ACROSS THE GULF OF MAINE INTO NEW ENGLAND. WIDELY VARYING SIGNALS THOUGH ON THE ORDER OF -2 TO -3 SD INDICATING AN ANOMALOUS SYSTEM THAT WOULD LIKELY EXCEED FORECAST CLIMATOLOGY. LOW CONFIDENCE AND LIMITED FORECAST CERTAINTY WITH SIGNIFICANT SPREAD OF ENSEMBLE MEMBER POSITIONS OF SURFACE LOW CENTERS. INTUITIVELY...THE NAO/AO BY THIS FORECAST TIMEFRAME TREND TOWARDS POSITIVE AND INDICATIONS OF NO UPSTREAM BLOCKING LEND TO BELIEVE THAT THE SYSTEM IN QUESTION WILL BE PROGRESSIVE THOUGH THE POSSIBLE PHASING WOULD RESULT IN IMPACTS LINGERING AS THE LOW OCCLUDES SOME- WHERE IN VICINITY TO THE GULF OF MAINE. BELIEVE NEW ENGLAND WILL FIND ITSELF BENEATH THE CYCLONIC BRANCH OF THE WARM-MOIST CONVEYER BELT REAR OF THE SYSTEM. MOISTURE TROWALING ISENTROPICALLY LIFTING TOWARDS MID-LEVEL F-GEN FORCING WOULD YIELD ROUGHLY N-S PRECIPITATION BANDING W/NW OF THE LOW EXACERBATED ON THE NE-FACING SLOPES OF HIGHER TERRAIN. WITH UNDERCUTTING COLDER AIR PER NW-FLOW THROUGH ALL LEVELS /< -5C H85 AIR REARWARD OF THE OCCLUSION PER ENSEMBLE MEANS...COLD-CONVEYER-BELT/...AND EVALUATING ENSEMBLE MEAN PROBABILITIES...COULD SEE INTERIOR SNOWS AND COASTAL SHOWERS. BUT ALSO PORTIONS OF NEW ENGLAND COULD BE BENEATH THE DRY-CONVEYER- BELT AND SEE LITTLE IF ANYTHING. HAVE HIGHEST PROBABILITIES FOR BELOW-FREEZING TEMPERATURES EXTEND FROM NW-CT INTO S-NH INCLUSIVE TO ALL POINTS N AND W. A MAJORITY OF THIS FORECAST DEPENDS UPON THE EVOLUTION OF N- AND S- STREAM ENERGY...WHICH AS THIS PRESENT TIME IS BEING POORLY SAMPLED BY IN-SITU OBSERVATIONS. OF CONCERN HAZARD-WISE IS THE POSSIBILITY OF WINTER-WEATHER HEADLINES FOR THE INTERIOR /ABSOLUTELY NO IDEA ON SNOWFALL AMOUNTS NOR PRECIPITATION AMOUNTS NOR EXACTLY WHERE THIS WILL ALL HAPPEN WITH THE DISPARITY IN FORECAST SOLUTIONS/...WIND- ADVISORY HEAD-LINES FOR PERHAPS EVERYWHERE...WITH GALES OVER THE WATERS /MAYBE EVEN STORM-FORCE HEADLINES/. LAPSE-RATES LOOKING TO BE WELL-MIXED BEYOND H5 WHERE MODEL SOLUTIONS HAVE A WIDE RANGE AROUND 45 TO 60 MPH. AS TO EARLY NEXT WEEK...COLD AIR STICKS AROUND INTO MIDWEEK. LOOKING A PERIOD OF BELOW-FREEZING TEMPERATURES FOR MUCH OF THE REGION OVER A PROLONGED TIME FRAME. WILL SEE A WARM-UP BY MIDWEEK AS ENSEMBLE MEANS SIGNAL SE-CONUS HIGH PRESSURE SHIFTING OFFSHORE TO BERMUDA ALLOWING FOR RETURN S-FLOW OF WARMER AIR.
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&& .AVIATION /20Z MONDAY THROUGH SATURDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...THROUGH TUESDAY NIGHT...HIGH CONFIDENCE. BEFORE 00Z... VFR. WNW WINDS GUST 15-20 KT THROUGH THE DAYLIGHT HOURS. AFTER 00Z...VFR WITH MODEST NW WIND BECOMING LIGHT AND SW LATE. LOW PROB OF SOME PATCHY GROUND FOG IN NORMAL PRONE REGIONS. TOMORROW AND TOMORROW NIGHT...VFR WITH SW WINDS INCREASING TO 20-25 KT LATE IN THE DAY. MID LEVEL CLOUDS WILL STREAM INTO THE REGION. KBOS...HIGH CONFIDENCE IN TAF. NW WIND GUSTS AROUND 20 KT POSSIBLE THROUGH THE AFTERNOON...DIMINISHING MAINLY THIS EVENING. KBDL...HIGH CONFIDENCE IN TAF. OUTLOOK...WEDNESDAY THROUGH SATURDAY. WEDNESDAY INTO WEDNESDAY NIGHT...MODERATE CONFIDENCE. MIX OF MVFR / LOW-END VFR AS A COLD FRONT SWEEPS THE TERMINALS WITH SCT -SHRA. SW-WINDS GUSTING UP TO 30 KTS...POSSIBLE 40 KTS WITH +RA. IMPROVING BEHIND THE FRONT WITH WINDS SHIFTING OUT OF THE NW. THURSDAY INTO THURSDAY NIGHT...HIGH CONFIDENCE. VFR. NW-WINDS DIMINISHING. FRIDAY INTO SATURDAY...LOW CONFIDENCE. CONDITIONS DETERIORATING WITH A DEVELOPING STORM SYSTEM IN VICINITY OF S NEW ENGLAND.
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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 /THROUGH TUESDAY NIGHT/...HIGH CONFIDENCE. TONIGHT...LIGHT NW WIND BECOMES SSW LATE. DRY WEATHER AND GOOD VSBY PREVAIL. TUES AND TUESDAY NIGHT...SSW WINDS INCREASE AS THE DAY PROGRESSES WITH SPEEDS REACHING 20-25 KT BY THE OVERNIGHT HOURS. DRY WEATHER AND GOOD VSBY CONTINUE. SEAS WILL BUILD TUES NIGHT IN RESPONSE...AND COULD SEE LINGERING 6FT ACROSS THE SOUTHERN WATERS. SCA MAY BE NEEDED. OUTLOOK...WEDNESDAY THROUGH SATURDAY... WEDNESDAY INTO WEDNESDAY NIGHT...MODERATE CONFIDENCE. COLD FRONT SWEEPS THE WATERS AROUND WEDNESDAY EVENING AHEAD OF WHICH SHOWERS WITH SOME EMBEDDED HEAVY DOWNPOURS ARE ANTICIPATED. SW-GUSTS UP TO 40 KTS POSSIBLE THOUGH GREATER CONFIDENCE WITH SUB-GALE WINDS. POSSIBLE THUNDER OVER THE FAR SE-WATERS. SEAS BUILDING AROUND 5-7 FEET LIKELY RESULTING IN SMALL-CRAFT HEADLINES. IMPROVING TOWARDS THURSDAY MORNING. THURSDAY INTO THURSDAY NIGHT...HIGH CONFIDENCE. QUIET BOATING WEATHER UNDER HIGH PRESSURE AND LIGHT NW-WINDS. FRIDAY INTO SATURDAY...LOW CONFIDENCE. CONDITIONS DETERIORATING AS A STORM BUILDS ACROSS NEW ENGLAND AND THE WATERS. EXPECTING NW-WINDS TO AMPLIFY TO GALE FORCE THROUGH THE PERIOD REQUIRING GALE WARNING HEADLINES...SEAS SUBSEQUENTLY BUILDING.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE.
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&& $$ SYNOPSIS...DUNTEN/SIPPRELL NEAR TERM...DUNTEN SHORT TERM...DUNTEN LONG TERM...SIPPRELL AVIATION...DUNTEN/SIPPRELL MARINE...DUNTEN/SIPPRELL

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