Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 280623 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 223 AM EDT TUE OCT 28 2014 .SYNOPSIS...
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MILD TEMPERATURES AND GENERALLY DRY CONDITIONS WILL CONTINUE TODAY. 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 THIS MORNING/...
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145 AM UPDATE... HIGH THIN CLOUDS MOVING ACROSS THE REGION EARLY THIS MORNING HAVE NOT STOPPED RADIATIONAL COOLING ACROSS NORMAL RADIATOR SITES ACROSS INTERIOR E MA INTO NE CT AND THE CT VALLEY OF SW NH/W MA AT 05Z. ALSO NOTING SOME PATCHY FOG BEGINNING TO FORM AS THESE TEMPS GETTING CLOSE TO DEWPTS. TEMPS HAVE FALLEN TO THE MID AND UPPER 30S ACROSS MOST LOCATIONS... WITH LOWER-MID 40S MAINLY ACROSS URBAN CENTERS AS WELL AS THE IMMEDIATE COAST. EXPECT TEMPS TO FALL BACK A FEW MORE DEGREES THEN...AS THE MID AND HIGH CLOUDS THICKEN AS SEEN ON CURRENT NE IR SATELLITE TRENDS...READINGS SHOULD LEVEL OFF OVER THE NEXT FEW HOURS. ALSO NOTING SOME ISOLD SHOWERS THAT DEVELOPED AHEAD OF WEAK WARM FRONT ACROSS N CENTRAL PA/CENTRAL NY ON NE REGIONAL 88D RADAR WHICH SHOULD DISSIPATE AS THEY SHIFT NE AND PASS ACROSS NORTHERN NEW ENGLAND THROUGH THE REMAINDER OF THE NIGHT. WIDER SHOWER ACTIVITY NOTED ACROSS THE NORTHERN TIER OF NY PUSHING TOWARD N VT/NH. HAVE UPDATED FORECAST TO REFLECT THESE CHANGES AND INCORPORATED THROUGH THE OVERNIGHT.
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
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THIS MORNING THROUGH TONIGHT... WARM FRONT WILL MOVE ACROSS THE REGION BY DAYBREAK...PUTTING SOUTHERN NEW ENGLAND INTO A WARM SECTOR TODAY. 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 TONIGHT TO +20C AND WITH AN APPROACHING COLD FRONT TO THE WEST...PRESSURE GRADIENT WILL TIGHTEN UP. GUSTS WILL CONTINUE UP TO AROUND 15-20 MPH AND WITH CLOUDS WILL RETURN FROM THE NORTHWEST AS 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. 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 NIGHT THROUGH MONDAY/... */ 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 DOWNSTREAM 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. && .AVIATION /06Z TUESDAY 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 WEDNESDAY...HIGH CONFIDENCE. THROUGH 12Z...VFR. EXPECT MID AND HIGH CLOUDS TO INCREASE. LIGHT/VRBL OR CALM WINDS. PATCHY FOG IN NORMALLY PRONE AREAS WITH LOCAL MVFR-IFR VSBYS. TODAY...VFR. MID LEVEL CLOUDS /AROUND 6KFT/ PUSH ACROSS N MA/S NH THROUGH MIDDAY...THEN CIGS INCREASE. PATCHY MVFR-IFR VSBYS IN LOCAL FOG THROUGH 13Z-14Z THEN IMPROVING. TONIGHT...MAINLY VFR. ISOLD TO SCT SHOWERS PUSH INTO CT VALLEY AFTER MIDNIGHT WITH LOCAL MVFR-IFR CIGS/VSBYS. LOW PROB OF LIFR CIGS/VSBYS ACROSS PORTIONS OF CT VALLEY IN ISOLD HEAVIER SHOWERS AND PATCHY FOG. S-SW WIND GUSTS UP TO AROUND 20 KT ACROSS S COAST...CAPE COD AND THE ISLANDS MAINLY AFTER MIDNIGHT. WEDNESDAY...MAINLY VFR. PATCHY MVFR-IFR CIGS/VSBYS IN SCT SHOWERS. S-SW WIND GUSTS UP TO 20-25 KT ALONG S COAST...CAPE COD AND THE ISLANDS BY MIDDAY THROUGH THE AFTERNOON. LOW PROB WIND GUST TO 30 KT. LOW PROB OF ISOLD TSTMS ACROSS E MA/S CENTRAL NH INTO E RI DURING THE AFTERNOON/EVENING. KBOS...HIGH CONFIDENCE IN TAF. KBDL...HIGH CONFIDENCE IN TAF. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... WEDNESDAY NIGHT...MODERATE CONFIDENCE. MIX OF MVFR TO LOW END IFR CIGS/ MVFR VSBYS AS A COLD FRONT SWEEPS THE TERMINALS WITH SCT -SHRA. 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. OVERNIGHT...LIGHT NW WINDS BECOME LIGHT/VRBL THROUGH 06Z THEN SHIFT TO S-SW TOWARD DAYBREAK. DRY WEATHER AND GOOD VSBY PREVAIL. TUESDAY 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 TUE 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... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...DUNTEN/SIPPRELL NEAR TERM...EVT SHORT TERM...DUNTEN LONG TERM...SIPPRELL AVIATION...SIPPRELL/EVT MARINE...SIPPRELL/EVT

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