Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 261200 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 700 AM EST FRI DEC 26 2014 .SYNOPSIS... A LARGE HIGH PRESSURE AREA OVER THE MID ATLANTIC STATES WILL DRIFT EASTWARD OFF THE COAST OF NORTH CAROLINA ON SATURDAY. THE WEST TO SOUTHWEST FLOW AROUND THIS HIGH WILL BRING DRY AND ABOVE NORMAL TEMPERATURES TO SOUTHERN NEW ENGLAND THROUGH SATURDAY. A COLD FRONT IS EXPECTED TO BRING SCATTERED RAIN SHOWERS ON SUNDAY. EXCEPT FOR A LOW PRESSURE SYSTEM THAT MAY GLANCE THE OUTER CAPE AND ISLANDS ON MON....MAINLY DRY AND COLDER THAN NORMAL CONDITIONS SHOULD PREVAIL FOR MOST OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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7 AM UPDATE... NO SIGNIFICANT CHANGES FROM PRIOR FORECAST. HAVE BKN-OVC CONDITIONS ALONG AND WEST OF AFN-IJD LINE AND MOSTLY CLEAR TO THE EAST. TREND WILL BE FOR CLOUDS TO DIMINISH IN THE W THIS AFTERNOON. TEMPERATURE FORECAST LOOKS GOOD WITH MINOR TWEAKS TO HOURLY TEMPERATURES AND NO CHANGE TO FORECASTED HIGHS. 3 AM UPDATE... LOW LEVEL MOISTURE AND CLOUDINESS WILL REMAIN QUITE EXTENSIVE TO OUR WEST AND INTO THE HIGHER TERRAIN OF WESTERN MA THROUGH MUCH OF TODAY. THE 925 MB RELATIVE HUMIDITY SEEN ON THE 00Z NAM MODEL DEPICTS THIS WELL. AREAS WEST OF A LINE FROM WINDSOR LOCKS CT TO BELCHERTOWN MA TO GARDNER MA SHOULD REMAIN PARTLY TO MOSTLY CLOUDY THIS MORNING AND EARLY AFTERNOON WHILE AREAS TO THE EAST SHOULD BE TOTALLY SUNNY. BY MID TO LATE AFTERNOON...THE CLOUDINESS IS FORECAST TO ERODE IN THE WEST. STRONG HIGH PRESSURE OVER THE MID ATLANTIC WILL KEEP A WESTERLY AIR FLOW ACROSS THE REGION TODAY. THERE IS STILL SOMEWHAT OF A GRADIENT LEFTOVER FROM LOW PRESSURE THAT HAS DEPARTED WELL TO OUR NORTHEAST...SO WE COULD GET SOME WIND GUSTS MIXING TO AROUND 15-25 MPH AT TIMES...MAINLY THIS MORNING...AND MAINLY IN THE HIGHER ELEVATIONS. WENT NEAR GUIDANCE FOR HIGH TEMPERATURES THIS AFTERNOON. WITH 925 MB TEMPERATURES NEARLY STEADY IN THE +2C TO +4C RANGE...EXPECTING HIGHS IN THE MID TO UPPER 40S... COOLER THAN YESTERDAY BUT WARMER THAN NORMAL.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... TONIGHT... CLEAR SKIES AND LIGHT WEST-SOUTHWEST WINDS WILL ALLOW TEMPERATURES TO DROP TO THE UPPER 20S AND LOWER 30S...EXCEPT MID AND UPPER 30S ON CAPE COD AND THE ISLANDS. SATURDAY...A BEAUTIFUL MARCH DAY...IN LATE DECEMBER. OUR WEATHER WILL STILL BE DOMINATED BY A LARGE HIGH PRESSURE SYSTEM WHICH WILL HAVE DRIFTED OFF THE NORTH CAROLINA COAST. WITH LIGHT SOUTHWEST WINDS AND A GOOD DEAL OF SUNSHINE...AM EXPECTING HIGH TEMPERATURES TO REBOUND SEVERAL DEGREES HIGHER THAN MODEL GUIDANCE WOULD INDICATE. 925 MB TEMPERATURES ARE FORECAST TO BE NEAR +6C AND AM FORECASTING HIGHS IN THE 50 TO 55 RANGE...SOME 10 TO 15 DEGREES ABOVE THE NORMAL FOR DECEMBER 27TH. WE COULD SEE SOME INCREASE IN HIGH CLOUDINESS DURING THE LATE AFTERNOON WELL IN ADVANCE OF A COLD FRONT FOR SUNDAY. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... HIGHLIGHTS... * JUST A CHANCE FOR RAIN SHOWERS WITH COLD FRONT ON SUNDAY * MOSTLY DRY AND COLDER FOR NEXT WEEK OVERVIEW... MEDIUM RANGE MODELS ARE IN REASONABLY GOOOD AGREEMENT FOR THIS FORECAST PERIOD AND THEN DIVERGE FAIRLY DRAMATICALLY AFTERWARDS. PATTERN LOOKS TO BE DOMINATED BY A NEGATIVE PNA WITH SHORTWAVE ENERGY DIGGING IN THE WESTERN USA AND A PERSISTENT RIDGE OFF THE SE USA COAST. SPLIT FLOW...A THEME OBSERVED QUITE A BIT LATE FALL INTO EARLY WINTER...IS ANTICIPATED DURING MUCH OF NEXT WEEK. THE NAO IS TRENDING NEGATIVE OVER THE NEXT WEEK WITH PREDICTIONS OF A SWITCH BACK TO POSITIVE. THIS ALL LEADS TO A SURFACE COLD FRONT PASSAGE SUNDAY THAT USHERS IN COLD AIR FOR NEXT WEEK BUT AT LEAST FOR THE MOST PART DRY. THE ECMWF DEPICTION OF AN INSIDE RUNNER AND A RETURN TO WARMER TEMPERATURES NEXT WEEKEND WOULD APPEAR TO BE CONSISTENT WITH A CHANGE BACK TO A POSITIVE NAO AND CONTINUATION OF A NEGATIVE PNA. DAY TO DAY... SUN...SURFACE COLD FRONT PASSAGE AND ASSOCIATED UPPER SHORT WAVE TROF HAVE JUST ENOUGH MOISTURE TO WARRANT LOW CHANCE FOR SHOWERS. PTYPE SHOULD BE LIQUID. COLDER AIR FOLLOWS SUN NIGHT WITH PARTIAL CLEARING NORTH BUT PROBABLY LINGERING HIGH OVERCAST SOUTH. MON...MODELS ALL SUGGEST THE FORMATION OF A SURFACE WAVE ALONG THE FRONT S OF NEW ENGLAND AND GENERALLY SUPPRESSED. THE 00Z ECMWF HAS TRENDED FURTHER N...AS THE CANADIAN HAS BEEN ADVERTISING FOR SEVERAL RUNS...WHILE THE GFS REMAINS WELL SUPPRESSED. IN LIGHT OF MODEL CONSENSUS AND SPREAD...HAVE KEPT SLIGHT CHANCE POPS OVER SE MA AND SOUTHERN RI AND NUDGE LOW CHANCE POPS CLOSE TO NANTUCKET. MON NIGHT THROUGH THU...LOOKS LIKE DRY AND COLD. HAVE LOWERED TEMPS BELOW MODEL CONSENSUS FOR SOME OF THIS PERIOD...ESPECIALLY TUE NIGHT. MIGHT NEED TO LOWER FURTHER IN LATER FORECASTS. SUSPECT MOST OF INTERIOR WILL DROP AT LEAST TO THE TEENS TUE NIGHT AND POSSIBLY EVEN BELOW 10 IN SOME NORMALLY COLDER SPOTS OF NW MA. ONE OR TWO SHORT WAVE TROFS EMBEDDED IN FAST ZONAL FLOW COULD PRODUCE A ROUND OR TWO OF FLURRIES BUT SEE LITTLE CHANCE FOR ANY MEASURABLE PRECIPITATION AT THIS POINT. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/...
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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 SATURDAY/...HIGH CONFIDENCE. TODAY...HIGH CONFIDENCE. VFR. BROKEN TO OVERCAST CLOUDS PERSISTING AT 35 HUNDRED TO AROUND 4000 FT IN WESTERN AND NORTH CENTRAL MA AND A SMALL PORTION OF HARTFORD COUNTY CT WITH CLEAR SKIES FOR THE REST OF CT/RI/EASTERN MA. W WINDS GUSTING TO 15-20 KT AT TIMES INVOF BERKSHIRES. EXPECT CLOUDS TO GRADUALLY DISSIPATE THIS AFTERNOON. TONIGHT...HIGH CONFIDENCE. VFR. BECOMING MOSTLY CLEAR NW MA. CLEAR SKIES ELSEWHERE. SATURDAY...HIGH CONFIDENCE. VFR. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...MODERATE TO HIGH CONFIDENCE IN TAF. KBDL WILL BE ON THE BORDER OF LOW CLOUDINESS AROUND 4000 FT TO THE NW AND SUNSHINE TO THE SE TODAY. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY... MODERATE TO HIGH CONFIDENCE. SAT NIGHT THROUGH SUN NIGHT...GENERALLY VFR EXCEPT POCKETS OF MVFR CIGS INVOF OF SCT SHOWERS POSSIBLE SUN. MON...VFR EXCEPT LOW CHANCE OF MVFR CIGS ACROSS AND S OF BID-MVY-ACK LINE. MON NIGHT THROUGH TUE...VFR CONDITIONS EXPECTED.
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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 SATURDAY/...HIGH CONFIDENCE. TODAY...SMALL CRAFT ADVISORIES REMAIN IN EFFECT FOR ALL OUTER WATERS THROUGH THIS MORNING...FOR A COMBINATION OF WIND GUSTS TO 25 KT AND SEAS NEAR 5 FT. WINDS AND SEAS WILL SUBSIDE THROUGHOUT THE DAY BUT THE 5 FT SEAS WILL LINGER MOST OF THE DAY OVER THE OUTER WATERS...ESPECIALLY ON THE SOUTH COAST. HAVE LET THE HEADLINES DROP ON THE NEARSHORE WATERS AT 7 AM EST. TONIGHT AND SATURDAY...WINDS AND SEAS BELOW SMALL CRAFT ADVISORY CRITERIA. WEST WINDS TONIGHT COULD STILL GUST TO 15 TO 20 KT AT TIMES...AND TO AROUND 15 KT SATURDAY FROM THE SOUTHWEST. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...MODERATE CONFIDENCE. SUN...SW FLOW AHEAD OF SURFACE COLD FRONT COULD BRING GUSTS TO NEAR 25 KT AND SEAS TO NEAR 5 FT IN THE OUTER WATERS. MAY BE ENOUGH GRADIENT BEHIND THE COLD FRONT FOR MARGINAL SCA CONDITIONS PERSISTING SUN NIGHT. MON...IF SURFACE WAVE ALONG THE FRONT PASSES CLOSE ENOUGH...COULD HAVE NE WINDS 20 TO 25 KT AND WAVES 5 TO 6 FT JUST SE OF NANTUCKET. TUE...WINDS AND SEAS ANTICIPATED TO BE BELOW SCA CONDITIONS.
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&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR ANZ231>235-237-251. SMALL CRAFT ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR ANZ250. SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ254>256. && $$ SYNOPSIS...GAF/THOMPSON NEAR TERM...GAF/THOMPSON SHORT TERM...GAF LONG TERM...THOMPSON AVIATION...GAF/THOMPSON MARINE...GAF/THOMPSON

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