Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 250938 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 438 AM EST THU DEC 25 2014 .SYNOPSIS...
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A COLD FRONT WILL MOVE OFFSHORE THIS MORNING FOLLOWED BY DRY AND WINDY CONDITIONS THIS AFTERNOON. DRY WEATHER AND ABOVE NORMAL TEMPERATURES WILL CONTINUE INTO SATURDAY. A COLD FRONT MAY BRING A FEW RAIN SHOWERS SUNDAY FOLLOWED BY COLDER CONDITIONS EARLY NEXT WEEK. THERE IS A LOW PROBABILITY THAT LOW PRESSURE PASSING TO OUR SOUTH ON TUESDAY COULD BE CLOSE ENOUGH TO CAUSE SOME SNOW BUT THAT IS FAR AWAY AT THIS POINT.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/... 330 AM UPDATE... TWO AREAS OF RAIN APPROACHING SNE EARLY THIS MORNING. RAIN ASSOCD WITH THE COLD FRONT WILL BE MOVING INTO WESTERN NEW ENG THROUGH 12Z WHILE A SECOND AREA OF HEAVIER SHOWERS AND A DEVELOPING FINE LINE ALIGNED WITH THE LOW LEVEL JET LIFTING NE FROM THE OCEAN. SPC MESOANALYSIS SHOWING MUCAPES ARUND 500 J/KG ACROSS SE MA AND CAPE COD BUT INSTABILITY AXIS IS MOVING EAST AND WILL BE OFFSHORE SO EXPECT THE FINE LINE TO REMAIN MOSTLY S AND E OF SNE...POSSIBLY CLIPPING ACK. HOWEVER...WE DO EXPECT CONVECTIVE SHOWERS WITH LOCALLY HEAVY DOWNPOURS DEVELOPING IN THE COASTAL PLAIN THIS MORNING ALONG THE LOW LEVEL JET AND SO WE WILL KEEP THE FLOOD WATCH FOR RI AND E MA...BUT WILL DROP IT ELSEWHERE. ALSO...WE KEPT THE WIND ADVISORY FOR MAINLY THE UPPER CAPE WHERE TEMPS IN THE LOWER 60S MAY ALLOW FOR ENOUGH MIXING WITH AXIS OF LOW LEVEL JET MOVING ACROSS THE REGION THROUGH 12Z. LOW LEVEL COOL AIR REALLY HANGING TOUGH IN THE CT VALLEY AND NE MA. WARMING INTO THE 50S STILL LIKELY...BUT NOT EXPECTED UNTIL THE COLD FRONT PASSES 10-12Z WITH MIXING OF WARMER AIR ALOFT TO THE SURFACE. TODAY...RAIN THIS MORNING WILL EXIT FROM WEST TO EAST 13-17Z WITH CAPE/ISLANDS THE LAST TO DRY OUT. EXPECT PT-MOSUNNY SKIES DEVELOPING IN THE AFTERNOON AS COLD ADVECTION DRIES OUT THE COLUMN...WITH MOST CLOUDS EXPECTED IN THE INTERIOR WHERE SUFFICIENT LOW LEVEL MOISTURE WILL SUPPORT BKN STRATO-CU. THE MAIN CONCERN THIS AFTERNOON IS STRONG WESTERLY WINDS AS STEEPENING LOW LEVEL LAPSE RATES ALLOWING MIXING OF STRONGER WINDS ALOFT. SOUNDINGS SUGGEST POTENTIAL FOR GUSTS TO 30-35 KT...WITH LOW PROB FOR NEAR WIND ADVISORY THRESHOLD OF 35-40 KT ACROSS HIGHER TERRAIN IN NORTHERN AND WESTERN MA. MAX TEMPS WILL OCCUR AROUND 12Z...WITH READINGS MOSTLY IN THE 50S...THEN FALLING INTO THE 40S DURING THE AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... TONIGHT... HIGH PRES BUILDS ACROSS THE MID ATLC REGION WITH RIDGING EXTENDING NORTH INTO SNE. EXPECT MOSTLY CLEAR SKIES WITH A FEW CLOUDS ACROSS CENTRAL AND W MA. GUSTY W WINDS DURING THE EVENING...DIMINISHING OVERNIGHT BUT REMAINING GUSTY ALONG THE COAST. MIN TEMPS RANGING FROM UPPER 20S TO MID 30S. FRIDAY... HIGH PRES SHIFTS TO THE MID ATLC COAST WITH MILD WESTERLY FLOW INTO NEW ENG. EXPECT MOSUNNY SKIES AND LIGHTER WINDS WITH HIGH TEMPS WELL INTO THE 40S AND NEAR 50 DEGREES IN THE COASTAL PLAIN. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
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* REMAINING DRY WITH ABOVE NORMAL TEMPERATURES SATURDAY * CHANCE OF SHOWERS SUNDAY * TURNING COLDER FOR NEXT WEEK. STILL A CHANCE OF SOME SNOW AROUND TUESDAY BUT HIGHLY UNCERTAIN. FRIDAY NIGHT AND SATURDAY...HIGH CONFIDENCE. HIGH PRESSURE BUILDS OVER THE MID ATLANTIC COAST FRI NIGHT AND SETTLES OFF THE COAST OF NORTH CAROLINA SAT. SOME DISCREPANCY IN MODEL FORECAST TEMPERATURES FOR SAT AFTERNOON WITH ECMWF COOLER THAN GFS...WITH 3C VS. 6C AT 925 MB. WITH MOSTLY SUNNY SKIES...LIGHT WINDS...AND SW FLOW ALOFT...AM OPTING FOR WARMER TEMPERATURES. HAVE GONE 5+ DEGREES WARMER THAN GUIDANCE...WITH HIGHS REACHING 50 TO 55 SAT AFTERNOON. SUNDAY...HIGH CONFIDENCE. STRONG LOW PRESSURE WILL MOVE ACROSS QUEBEC AND FAR NORTHERN MAINE. A COLD FRONT TRAILING FROM THE LOW WILL MOVE ACROSS SOUTHERN NEW ENGLAND. SKIES WILL BE CLOUDY BUT MOISTURE WILL BE LIMITED AND THERE IS ONLY A CHANCE OF SOME LIGHT RAIN SHOWERS WITH THIS FRONT ...MAINLY IN THE MORNING AND EARLY AFTERNOON. EXPECTING SKIES TO BECOME MOSTLY SUNNY AGAIN BY LATE IN THE DAY...FROM NW TO SE. COOLER BUT STILL ABOVE NORMAL TEMPERATURES WITH HIGHS IN THE 40S. MONDAY AND TUESDAY... LOW CONFIDENCE ON PRECIPITATION BUT MODERATE TO HIGH CONFIDENCE ON TEMPERATURE. WHAT WE ARE CONFIDENT OF IS THAT COLDER AIR RETURNS TO THE REGION. AFTER ALL...IT WILL BE THE END OF DECEMBER. LOOKING FOR HIGHS IN THE 30S AND LOWS IN THE 20S...COULD EVEN SEE SOME UPPER TEENS IN NORTHWEST MA LATE MONDAY NIGHT. HOWEVER...THERE REMAINS A GREAT DEAL OF UNCERTAINTY IN THE EVOLUTION OF THE WEATHER PATTERN BY TUESDAY. MONDAY LOOKS TO BE PARTLY CLOUDY BUT WITH CLOUDS INCREASING BY NIGHTFALL. FOR SEVERAL RUNS NOW...THE ECMWF HAS COME INTO AGREEMENT WITH THE OPERATIONAL GFS RUNS WHICH SUPPRESS A LOW PRESSURE SYSTEM TO OUR SOUTH AND LEAVE US DRY. THE CANADIAN MODEL ALSO AGREES THAT THE LOW WILL BE WELL SOUTH OF THE REGION BUT HAS A MUCH BROADER AREA OF PRECIPITATION TO THE NORTH...SUCH THAT WE COULD SEE SOME SNOW FROM THE NORTHERN FRINGES. CLOSER INSPECTION OF THE GFS ENSEMBLES LEADS ONE NOT TO DISMISS THIS SYSTEM QUITE YET. A FEW OF THE GEFS MEMBERS HAVE LOW PRESSURE MUCH FARTHER TO THE NORTH...OFF THE NJ COAST OR SOUTH OF THE ISLANDS. YET OTHER MEMBERS HAVE STRONG HIGH PRESSURE BUILDING IN AND NO LOW AT ALL. HENCE...A HIGH LEVEL OF UNCERTAINTY EXISTS. ANOTHER POSSIBILITY IS THAT SKIES COULD BECOME CLOUDY WITH SCATTERED SNOW SHOWERS AS A RESULT OF THE COLD POOL ALOFT COMING OVER SOUTHERN NEW ENGLAND TUE. FOR NOW...HAVE OPTED TO INCLUDE SLIGHT CHANCE PROBABILITIES OF SNOW FOR OUR REGION TO ACKNOWLEDGE THE POSSIBILITY BUT LEAN TOWARD THE SOUTHERN SOLUTIONS. WEDNESDAY...MODERATE CONFIDENCE. WED LOOKS TO BE A DRY AND SEASONABLY COLD DAY WITH HIGHS MAINLY FROM 30 TO 35.
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&& .AVIATION /09Z THURSDAY THROUGH MONDAY/...
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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 FRIDAY/... THROUGH 12Z...WIDESPREAD IFR/LIFR CONTINUES IMPROVING TOWARD 12Z IN THE CT VALLEY. AREAS OF DENSE FOG NORTH AND WEST OF THE WARM FRONT IN THE INTERIOR WILL IMPROVE AS THE FRONT LIFTS N. RENEWED AREA OF RAIN REDEVELOPS ACROSS SNE 08-12Z AS THE COLD FRONT APPROACHES. SW GUSTS TO 35-40 KT POSSIBLE ACROSS PORTIONS OF RI AND SE MA. TODAY...HIGH CONFIDENCE ON TRENDS. LOWER CONFIDENCE ON TIMING. IFR/MVFR CONDITIONS WILL IMPROVE TO VFR FROM WEST TO EAST 14-18Z AS THE RAIN MOVES OFFSHORE. GUSTY WEST WINDS DEVELOPING LATE MORNING THROUGH THE AFTERNOON WITH GUSTS TO 30-35 KT. LOW PROB FOR G40 KT OVER HIGHER ELEVATIONS IN NORTHERN AND WESTERN MA. TONIGHT...HIGH CONFIDENCE. VFR. W WINDS GUSTING TO 25-30 KT EARLY...HIGHEST ALONG COAST...THEN DIMINISHING AFTER MIDNIGHT. FRIDAY...HIGH CONFIDENCE. VFR. KBOS TERMINAL...HIGH CONFIDENCE IN TAF TRENDS. TIMING OF WARM FRONT MAY BE TOO FAST BY A FEW HOURS BUT WE DO EXPECT WIND SHIFT TO S BEFORE DAYBREAK. KBDL TERMINAL...HIGH CONFIDENCE IN TAF TRENDS. OUTLOOK...FRIDAY NIGHT THROUGH MONDAY... FRIDAY NIGHT AND SATURDAY...HIGH CONFIDENCE VFR. SUNDAY...MODERATE CONFIDENCE. MVFR POSSIBLE IN SCATTERED RAIN SHOWERS. MONDAY...MODERATE CONFIDENCE. MAINLY VFR. CONDITIONS MAY LOWER TO MVFR MONDAY NIGHT.
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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 FRIDAY/...HIGH CONFIDENCE. TODAY...PREFRONTAL SW WINDS ARE BELOW GALE...BUT AFTER WIND SHIFT TO WEST...STEEPENING LOW LEVEL LAPSE RATES WILL ALLOW FOR GUSTS TO INCREASE TO 35 KT ESPECIALLY THIS AFTERNOON. GALE WARNINGS ARE IN EFFECT FOR ALL WATERS EXCEPT BOSTON HARBOR AND NARRAGANSETT BAY. TONIGHT...NEAR GALES OVER THE OUTER WATERS IN THE EVENING...OTHERWISE SCA WIND GUSTS WITH GRADUAL DIMINISHING WIND OVERNIGHT. FRIDAY...DIMINISHING WIND BELOW SCA WITH SUBSIDING SEAS. OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...MODERATE CONFIDENCE. FRIDAY NIGHT AND SATURDAY...SEAS MAY STILL BE NEAR 5 FT OVER THE OUTER WATERS FRI NIGHT BUT SHOULD SUBSIDE TO BELOW SCA CRITERIA BY SAT. SW TO W WINDS COULD STILL GUST TO 15-20 KT AT TIMES. SUNDAY...A COLD FRONT WILL MOVE ACROSS THE WATERS. SW WINDS WILL SHIFT TO THE NW BUT SPEEDS SHOULD BE BELOW SCA CRITERIA. SEAS COULD BUILD TO 5 FT ON THE OUTER WATERS. SCATTERED SHOWERS COULD CAUSE SOME BRIEF VISIBILITY RESTRICTIONS. MONDAY...RELATIVELY LIGHT NW TO N WINDS EXPECTED. SEAS BELOW 3 FT. THERE IS A LOW PROBABILITY THAT WINDS COULD BECOME NE LATE AT NIGHT IF LOW PRESSURE SOUTH OF NEW ENGLAND COME FARTHER NORTH THAN EXPECTED TOWARD TUESDAY MORNING.
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&& .CLIMATE... RECORD HIGHS FOR TODAY / CHRISTMAS DAY BOS...61 IN 1996 / 65 IN 1889 PVD...60 IN 1990 / 63 IN 1964 BDL...59 IN 1996 / 64 IN 1964 ORH...57 IN 1996 / 60 IN 1964 && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...FLOOD WATCH UNTIL NOON EST TODAY FOR MAZ005>007-013>022. WIND ADVISORY UNTIL 8 AM EST THIS MORNING FOR MAZ022. RI...FLOOD WATCH UNTIL NOON EST TODAY FOR RIZ001>007. MARINE...GALE WARNING FROM 10 AM THIS MORNING TO 7 PM EST THIS EVENING FOR ANZ232>234. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ230-236. GALE WARNING FROM NOON TODAY TO 7 PM EST THIS EVENING FOR ANZ231-251. GALE WARNING FROM 9 AM THIS MORNING TO 7 PM EST THIS EVENING FOR ANZ235-237. GALE WARNING FROM NOON TODAY TO 10 PM EST THIS EVENING FOR ANZ250. GALE WARNING UNTIL 10 PM EST THIS EVENING FOR ANZ254>256.
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&& $$ SYNOPSIS...KJC/GAF NEAR TERM...KJC SHORT TERM...KJC LONG TERM...GAF AVIATION...KJC/GAF MARINE...KJC/GAF CLIMATE...STAFF

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