Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 200324 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1024 PM EST WED NOV 19 2014 .SYNOPSIS... HIGH PRESSURE OVER THE REGION MOVES EAST TONIGHT...THEN A WEAK DISTURBANCE MAY BRING A FEW SNOW SHOWERS TO THE SOUTH COAST TONIGHT. ANOTHER SHOT OF UNSEASONABLY COLD AIR IS EXPECTED THURSDAY NIGHT INTO SATURDAY. A SIGNIFICANT WARM-UP IS IN STORE BY SUNDAY INTO EARLY NEXT WEEK. A STORM MOVING OUT OF TEXAS WILL LIKELY BRING RAIN TO SOUTHERN NEW ENGLAND SUNDAY NIGHT INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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1020 PM UPDATE... LOW AND MID LEVEL CLOUDS HAVE OVERSPREAD THE REGION. RADAR SHOWING SOME LIGHT PRECIP WHICH IS MAINLY ALOFT MOVING ACROSS SNE. STILL A LOT OF DRY AIR IN THE LOW LEVELS TO OVERCOME PER 00Z SOUNDINGS AND LARGE T/TD DEPRESSIONS. AFTER MIDNIGHT...THE FOCUS FOR SNOW/RAIN SHOWERS WILL SHIFT TO THE S COAST AND CAPE/ISLANDS. INCREASING SW WIND HAS BROUGHT IN MILDER AIR OVER THE CAPE/ISLANDS WHERE TEMPS ALREADY UPPER 30S TO AROUND 40. ANY PRECIP HERE LIKELY MOSTLY RAIN. BUT JUST INLAND FROM THE CANAL TEMPS DOWN IN THE 20S WITH LIGHT WINDS. TEMPS EXPECTED TO RISE OVERNIGHT INTO THE 30S ALONG THE COASTAL PLAIN AS SW WINDS INCREASE. IN FACT...GUSTS TO 30+ MPH LIKELY ACROSS CAPE/ISLANDS OVERNIGHT AND IMMEDIATE S COAST. PREVIOUS DISCUSSION... THE SURFACE LOW WILL MOVE FROM THE GREAT LAKES OVER CANADA...PASSING TO OUR NORTH. THIS INCREASES THE PRESSURE GRADIENT SURFACE AND ALOFT AND BRINGS INCREASING SOUTHWEST WINDS. A 40 TO 50 KNOT LOW LEVEL JET WILL ENTER NEW ENGLAND AROUND MIDNIGHT AND REMAIN OVERHEAD THROUGH THE NIGHT. THE BEST JET DYNAMICS WILL REMAIN TO OUR WEST AND NORTH. SO ANY PCPN DIRECTLY CONNECTED TO THE CLIPPER LOW WILL BE LIGHT AND MOSTLY TO OUR NORTH. THE SOUTHWEST FLOW OFF THE OCEAN WILL BRING GREATER INSTABILITY INTO THE SOUTH COAST AREA...TOTAL TOTALS ARE FORECAST IN THE MID 40S WHICH WOULD SUPPORT SCATTERED RAIN/SNOW SHOWERS. SO THE FORECAST WILL BRING INCREASING CLOUDS...CHANCE POPS OVER THE CAPE/ISLANDS/SOUTH COAST...AND INCREASING WIND OVER THE OCEAN AND ALONG COASTAL AREAS. FOR MIN TEMPS WE STAYED CLOSE TO GUIDANCE WITH VALUES IN THE 20S INLAND AND LOW TO MID 30S CAPE/ISLANDS.
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&& .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... THURSDAY... THE CLIPPER PASSES NORTH OF US DURING THE DAY AND SWINGS A COLD FRONT THROUGH THE REGION. WE MAY START OUT WITH SOME CLOUDS AS THE FRONT MOVES THROUGH BUT SHOULD SEE CLEARING FROM WEST TO EAST DURING THE DAY. SUNSHINE WILL PROMOTE MIXING UP TO 850 MB AND DRAW SOME OF THAT WIND TO THE SURFACE OVER LAND. THE 40 KNOT WINDS AT 850 MB FIRST THING IN THE MORNING WILL DIMINISH TO 25-30 KNOTS INLAND...BUT MAY LINGER OVER THE CAPE AND ISLANDS. THE WINDS THAT ARE THERE AROUND MIDDAY WILL BE MIXED TO THE SURFACE IN GUSTS. WE USED 25 KNOTS NORTHWEST TO 35 KNOTS CAPE AND ISLANDS. TEMPERATURES INITIALLY IN THE MIXED LAYER WOULD SUPPORT SFC MAX TEMPS IN THE 40S. BUT COLD ADVECTION FROM THE WEST WILL LOWER THESE VALUES IN THE AFTERNOON SO MAX TEMPS SHOULD BE MORE LIKE 35 TO 45...COLDEST NORTHWEST. THURSDAY NIGHT... HIGH PRESSURE OVER THE PLAINS AND LOW PRESSURE OVER THE MARITIMES WILL FAVOR WEST WINDS...BUT THE GRADIENT WILL BE DIMINISHING AND SO THE WINDS WILL ALSO DIMINISH. A SHORTWAVE MOVES OVERHEAD AND MAY SUPPORT A FEW CLOUDS ESPECIALLY NORTH OF THE MASS PIKE. BUT THE AIRMASS WILL BE DRY SO SKY COVER WILL BE LIMITED. THE COLDEST TEMPS AND CONTOUR HEIGHTS WILL MOVE IN THURSDAY NIGHT...SO TEMPS WILL BE A FEW DEGREES COOLER THAN TONIGHT. WE USED UPPER TEENS TO MID 20S. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... HIGHLIGHTS... * ANOMALOUS COLD FRIDAY GIVING WAY TO MODERATING TEMPS THIS WEEKEND * MUCH WARMER SUNDAY THROUGH TUESDAY * RAINSTORM LIKELY SUNDAY AND MONDAY MODELS ARE IN DECENT AGREEMENT THROUGH THE WEEKEND. SOME DETAIL DIFFERENCES...AND IN SOME CASES...LARGE SCALE DIFFERENCES START GETTING INTO THE MODELS EARLY NEXT WEEK. THE ANOMALOUS UPPER TROUGH THAT HAS BROUGHT SO MUCH COLD WEATHER TO THE COUNTRY WILL SLOWLY PUSH OFFSHORE FRIDAY. A BRIEF...WEAK UPPER LEVEL RIDGE WILL CREST OVER THE AREA OVER THE WEEKEND. THEN ANOTHER TROUGH MOVING INTO THE GREAT LAKES WILL PUSH THE RIDGE OFFSHORE. A SOUTHERN STREAM LOW PRESSURE SYSTEM WILL MOVE INTO THE GREAT LAKES MERGING WITH ANOTHER LOW PRESSURE THERE. THIS WILL MOVE INTO QUEBEC BRINGING WARM MOIST AIR INTO SOUTHERN NEW ENGLAND SUNDAY AND MONDAY. BEYOND THIS...THE MODELS START LOSING THEIR AGREEMENT. A COLD FRONT WILL MOVE THROUGH SOUTHERN NEW ENGLAND SOMETIME MONDAY INTO TUESDAY LIKELY WITH HIGH PRESSURE MOVING IN BEHIND. THE GFS HAS A SERIES OF LOW PRESSURE SYSTEMS AFFECTING ONE PORTION OF SOUTHERN NEW ENGLAND OR ANOTHER TUESDAY AND WEDNESDAY BUT GIVEN THE OPERATIONAL ECMWF AGREES WITH BOTH THE GFS AND ECMWF ENSEMBLE MEANS PREFER TO GO WITH THE ECMWF SOLUTION. FRIDAY...BEHIND A COLD FRONT MOVING THROUGH THURSDAY...COLD AIR SPILLS INTO THE REGION ON NORTHWEST WINDS AIDED BY HIGH PRESSURE TO THE SOUTHWEST. HIGHS SHOULD BE IN THE LOW TO MID 30S ACROSS THE INTERIOR AND MID TO UPPER 30S ALONG THE COAST ALONG WITH BLUSTERY NORTHWESTERLY WINDS. SATURDAY...TEMPERATURES BEGIN TO MODERATE AS SURFACE FLOW SHIFTS TO THE SOUTHWEST. HIGH PRESSURE WILL SLIDE SOUTH OF SOUTHERN NEW ENGLAND. AS WINDS SHIFT TO THE SOUTHWEST AND WARMER AIR STARTS TO MOVE INTO THE REGION...COULD SEE A FEW SHOWERS DEVELOP OVER THE AREA. HIGH TEMPERATURES WILL GENERALLY BE IN THE 30S. SUNDAY AND MONDAY...A WARM FRONT WILL MOVE INTO THE REGION EARLY SUNDAY AS LOW PRESSURE MOVES INTO THE GREAT LAKES. SHOWERS ARE LIKELY WITH LIFT FROM THE FRONT. BUT EVEN WITH INCREASING CLOUDS AND SHOWERS...TEMPS WILL WARM SIGNIFICANTLY AS WARMER MOIST AIR TRAVELS IN ON THE SOUTHERLY WINDS. HIGHS WILL BE AT LEAST 10 TO 15 DEGREES WARMER THAN FRIDAY AND SATURDAY WITH 850MB TEMPERATURES 1 TO 2 STANDARD DEVIATIONS ABOVE NORMAL. THEN SUNDAY NIGHT...CLOUDS WILL THICKEN AS LOW PRESSURE APPROACHES FROM THE GREAT LAKES. PRECIPITATION WILL START OVERNIGHT SUNDAY AND CONTINUE INTO MONDAY. THIS MAY START AS SNOW OR A MIX OF RAIN AND SNOW EARLY ON ACROSS THE INTERIOR...THEN CHANGE OVER TO RAIN EARLY IN THE DAY MONDAY. PWATS ARE 1 TO 2 STANDARD DEVIATIONS ABOVE NORMAL...SO HEAVY RAIN IS A CONCERN. EXPECTING LESS THAN AN INCH OF RAIN ACROSS THE REGION...BUT LOCALLY HEAVIER AMOUNTS ARE POSSIBLE. FINALLY...A 50 TO 70 KNOT LOW LEVEL JET WILL BRING GUSTY WINDS TO THE REGION IF THEY ARE ABLE TO MIX DOWN TO THE SURFACE. THERE ARE DECENT LAPSE RATES AND THE RAIN WILL HELP BRING THESE WINDS TO THE SURFACE SO MAY BE LOOKING AT SOME DECENT WINDS AT SOME POINT DURING THE SUNDAY NIGHT TO MONDAY TIME FRAME. TUESDAY...MAY SEE SOME LINGERING RAIN AS THE COLD FRONT PUSHES THROUGH SOUTHERN NEW ENGLAND SOMETIME MONDAY NIGHT INTO TUESDAY. OTHERWISE...WILL START TO SEE COOLER TEMPERATURES AND DRIER WEATHER. WEDNESDAY...HIGH PRESSURE BUILDS INTO THE REGION AND COLDER TEMPERATURES MOVE BACK IN. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...HIGH CONFIDENCE. TONIGHT...INCREASING SOUTHWEST FLOW OVERNIGHT WITH INCREASING SKY COVER. MOST AREAS WILL BE VFR WITH CLOUD BASES LOWERING TO 4000-5000 FEET. SOUTHWEST WIND OFF THE OCEAN MAY BRING SCATTERED SNOW SHOWERS TO PARTS OF THE SOUTH COAST OF RI AND MASS INCLUDING THE CAPE AND ISLANDS. CIGS WOULD LOWER TO MVFR IN/NEAR ANY SNOW SHOWERS WITH VSBYS OF 3 MILES. PROBABILITY OF SNOW IS TOO LOW FOR IT TO APPEAR IN THE TAFS AT THIS TIME. THURSDAY...VFR. CLEARING SKIES. WEST-SOUTHWEST WINDS GUSTING 20-30 KNOTS EXCEPT 30-35 KNOTS CAPE AND ISLANDS. THURSDAY NIGHT...CLEARING SKIES. WEST WINDS DIMINISHING INLAND BUT GUSTING 20-30 KNOTS ALONG THE COAST AND ISLANDS. KBOS TERMINAL...HIGH CONFIDENCE. KBDL TERMINAL...HIGH CONFIDENCE. OUTLOOK...FRIDAY THROUGH MONDAY... FRIDAY AND SATURDAY...HIGH CONFIDENCE. MAINLY VFR. INCREASING CLOUDS SATURDAY NIGHT. SUNDAY AND MONDAY...MODERATE CONFIDENCE. MVFR/IFR CONDITIONS LIKELY IN RAIN/FOG. MAY START AS A WINTRY MIX ACROSS THE NORTHWESTERN ZONES SUNDAY NIGHT. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH THURSDAY. TONIGHT...SOUTHWEST WINDS ALOFT WILL INCREASE DURING THE NIGHT. THE COMBINATION OF COLD AIR ALOFT AND RELATIVELY WARM OCEAN TEMPS...10-14C...WILL ENCOURAGE SOME OF THIS WIND DOWN TO THE OCEAN SURFACE. THE SOUTHWEST LOW LEVEL JET HAS SPEEDS OF 35 TO 40 KNOTS...SO THAT MEANS A GOOD POTENTIAL FOR GALE FORCE SOUTHWESTERS LATER TONIGHT. A GALE WARNING HAS BEEN ISSUED FOR THE OUTER WATERS/SOUTHERN SOUNDS/CAPE COD BAY WITH SMALL CRAFT ADVISORIES FOR NARRAGANSETT BAY/BOSTON HARBOR/MASS BAY. MASS BAY WINDS ARE BORDERLINE AND MAY NEED TO BE UPGRADED OVERNIGHT. THURSDAY...CONTINUED WEST TO SOUTHWEST WINDS AS A COLD FRONT APPROACHES THE WATERS. CONTINUED SPEEDS OF 35 KNOTS MOST WATERS WHERE GALES WARNINGS WILL CONTINUE. CONTINUED 25-30 KNOTS CLOSER TO SHORE WHERE SMALL CRAFT ADVISORY WILL CONTINUE. THURSDAY NIGHT...WINDS AND SEAS WILL DIMINISH DURING THE NIGHT. BUT WEST-SOUTHWEST GALES MAY LINGER ON THE OUTER WATERS FOR A FEW HOURS EARLY IN THE NIGHT BEFORE GOING SUB-GALE. OUTLOOK...FRIDAY THROUGH MONDAY... FRIDAY...NEAR GALE FORCE WESTERLY WINDS ARE LIKELY THEN DIMINISHING OVERNIGHT. SEAS WILL DIMINISH SLOWLY AGAIN MAINLY OVERNIGHT. SATURDAY...THERE WILL BE A BRIEF PERIOD OF BELOW SCA CONDITIONS DURING THE DAY SATURDAY...THEN WINDS AND SEAS PICK UP AGAIN SATURDAY NIGHT. SUNDAY AND MONDAY...SOUTHWESTERLY WINDS SHIFT TO THE SOUTHEAST SUNDAY MORNING THEN BACK TO THE SOUTHWEST MONDAY AFTERNOON AS A WARM FRONT MOVES OVER THE WATERS. SEAS GENERALLY 5 TO 9 FEET ON THE OUTER WATERS. SMALL CRAFT ADVISORIES LIKELY. && .CLIMATE... RECORD LOW MAX TEMPS TODAY... ACTUAL MAX TEMPS TODAY... BOSTON 30/189737 PROVIDENCE33/1936 36 HARTFORD33/1955 36 WORCESTER29/2008 30 BLUE HILL27/189734 && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...GALE WARNING FROM 4 AM TO 7 PM EST THURSDAY FOR ANZ231>234-250- 254. SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR ANZ230-236. GALE WARNING UNTIL 7 PM EST THURSDAY FOR ANZ235-237-255-256. SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR ANZ251.
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&& $$ SYNOPSIS...WTB NEAR TERM...WTB/KJC SHORT TERM...WTB LONG TERM...RLG AVIATION...WTB/RLG MARINE...WTB/RLG CLIMATE...

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