Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 242239 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 539 PM EST WED DEC 24 2014 .SYNOPSIS...
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STRONG LOW PRESSURE TRACKING ACROSS THE GREAT LAKES WILL BRING HEAVY RAINFALL AND GUSTY WINDS THROUGH CHRISTMAS. DRY WEATHER WITH ABOVE NORMAL TEMPERATURES WILL FOLLOW FROM CHRISTMAS AFTERNOON INTO SATURDAY. A COLD FRONT MAY BRING A FEW RAIN OR SNOW SHOWERS SUNDAY. ANOTHER STORM MAY AFFECT US LATE MONDAY INTO WEDNESDAY.
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&& .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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MODERATE TO HIGH CONFIDENCE...LOWER WITH RESPECT TO WIND POTENTIAL. AREA OF MODERATE TO OCCASIONALLY HEAVY RAINFALL MOVING ACROSS E CT/RI/SE MA AT 21Z WITH MORE BANDS OF HEAVY RAIN MOVING NE OFF THE DE/S NJ COAST SEEN ON LATEST NE REGIONAL 88D RADAR IMAGERY. NOTING 0.25 TO 0.6 INCHES OF RAIN IN LAST 3 HRS /TO 21Z/ ACROSS LONG ISLAND...BLOCK ISLAND AND INTO S COASTAL CT. BULK OF PRECIP WILL CONTINUE TO STREAM UP THE COAST WITH INCREASING PWATS. KEPT PRECIP TOTALS ON ORDER OF 1-2 INCHES...BUT COULD SEE LOCALLY HIGHER AMOUNTS MAINLY ACROSS NE CT/RI/SE MA. WARM FRONT APPEARS TO BE SITTING ACROSS S COASTAL AREAS. STILL HAVING A TOUGH TIME MOVING N WITH LIGHT N-NE WINDS IN PLACE WITH JUST ENOUGH DRAINAGE AND COLD AIR DAMMING. NOTING PRES FALLS OF 3-4 MB/3 HR /TO 21Z/ WITH FASTEST FALLS ACROSS E NY INTO W VT. COLD FRONT ACROSS CENTRAL OH/WESTERN WV AND E KY AT 21Z WILL EVENTUALLY SHIFT E...WHICH SHOULD PUSH THE WARM FRONT NORTHWARD OVERNIGHT. AS COLD FRONT APPROACHES OVERNIGHT...SOME QUESTION AS TO WHETHER THERE WILL BE A FINE LINE ASSOCIATED WITH IT. IF THIS DOES DEVELOP...WILL NEED TO MONITOR FOR BRIEF STRONG WIND GUSTS AS IT CROSSES THE REGION. ALSO...PRETTY GOOD INSTABILITY STARTING TO MOVE IN WITH LI/S FROM ZERO TO -2 AND K INDICES IN THE LOWER-MID 30S. MAY SEE ISOLD THUNDERSTORMS DEVELOP AHEAD OF THE COLD FRONT OVERNIGHT. STRONG INFLUX OF MILDER TEMPS MOVE IN WITH THE WARM FRONT PASSAGE...SO TEMPS TO RISE THROUGH THE NIGHT INTO THE 50S...AND POSSIBLY TO THE LOWER 60S ACROSS PORTIONS OF E MA BEFORE SUNRISE. THIS WILL APPROACH RECORD LEVELS /SEE LISTING IN CLIMATE SECTION BELOW/. STILL SOME QUESTION AS TO HOW MUCH WIND WILL MIX DOWN. NOTING LITTLE IF ANY MIXING BELOW 900 HPA SO WILL BE TOUGH TO MIX DOWN THE STRONG JET ASSOCIATED WITH THIS SYSTEM...ON ORDER OF 50-60 KT AT H9 AND H85. IF FINE LINE MENTIONED ABOVE DOES MATERIALIZE... MIGHT SEE IT. SOMETHING TO MONITOR CLOSELY. FOR NOW...HAVE MENTIONED WIND GUSTS UP TO 30-35 KT FOR MOST AREAS...AND COULD REACH AROUND 40 KT ACROSS RI/SE MA WHERE SOME MIXING WILL START TO WORK IN AHEAD OF COLD FRONT AFTER MIDNIGHT AS THE CORE OF THE 900 AND 850 HPA JETS MOVE ACROSS EASTERN AREAS.
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&& .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
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CHRISTMAS DAY...HIGH CONFIDENCE. SHORT RANGE MODELS IN VERY GOOD AGREEMENT IN PUSHING FRONT OFFSHORE BY MID MORNING WITH LEFTOVER SHOWERS MOVING OFFSHORE AS DRY SLOT WORKS IN. WINDS SHIFT TO W-SW WITH DRIER AIR WORKING IN. LAPSE RATES STEEPEN ESPECIALLY FROM 900 HPA AND BELOW WHICH WILL ALLOW GOOD MIXING TO WORK IN. QUESTION IS HOW STRONG WILL THE GUSTS BE. AT THIS POINT...CONTINUED TO SEE WIND GUSTS JUST BELOW WIND ADVISORY CRITERIA...THOUGH COULD BE SOME MARGINAL GUSTS TO CRITERIA MAINLY ALONG THE S COAST...CAPE COD AND THE ISLANDS THU AFTERNOON. MIGHT ALSO SEE SOME HIGHER GUSTS ACROSS THE HIGHER INLAND TERRAIN OF THE WORCESTER HILLS AND MONADNOCKS AS WELL AS THE E SLOPES OF THE BERKSHIRES. KEPT ADVISORY THROUGH LATE MORNING ACROSS RI/SE MA...BUT MAY NEED TO EXTEND INTO THE AFTERNOON. WITH GENERAL OVERALL MID LEVEL STEERING CURRENTS FROM W-E...NOT MUCH COLD AIR TO TRANSPORT INTO THE REGION. TEMPS WILL HOLD IN THE 50S DURING THE MORNING BEFORE STARTING TO SLOWLY FALL BACK THU AFTERNOON WITH THE INCREASING WIND. CHRISTMAS NIGHT...HIGH CONFIDENCE. HIGH PRES RIDGE BEGINS TO BUILD E OUT OF THE APPALACHIANS. WINDS WILL SHIFT TO W-NW. WINDS WILL REMAIN GUSTY EARLY THU NIGHT...THEN WILL DIMINISH OVERNIGHT WITH DRY CONDITIONS. COLDER AIR REMAINS N OF THE REGION. WITH GENERALLY MOSTLY CLEAR SKIES IN PLACE...THOUGH SOME CLOUDS LINGER ACROSS NW MA...TEMPS WILL FALL BACK TO THE UPPER 20S ACROSS N CENTRAL AND W MA TO THE UPPER 30S ON THE OUTER CAPE AND NANTUCKET. THESE READINGS ARE AROUND 10 DEGREES ABOVE SEASONAL NORMALS FOR LATE DECEMBER.
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&& .LONG TERM /FRIDAY THROUGH WEDNESDAY/... * CLEARING...WINDY AND MILD CHRISTMAS DAY. * REMAINING DRY WITH ABOVE NORMAL TEMPERATURES FRI AND SAT. * POTENTIAL FOR SOME RAIN OR SNOW EARLY NEXT WEEK. FRIDAY AND SATURDAY...HIGH CONFIDENCE. HIGH PRESSURE BUILDS TO THE MID ATLANTIC COAST. DRY WEATHER WILL PREVAIL WITH LIGHTER WINDS. TEMPERATURES WILL REMAIN ABOVE AVERAGE WITH HIGHS IN 40S BOTH DAYS AND LOWS MAINLY IN 30S. SUNDAY THROUGH WEDNESDAY...LOW CONFIDENCE. MODELS DROP A WEAK COLD FRONT THROUGH SOUTHERN NEW ENGLAND SUNDAY. MOISTURE APPEARS TO BE LIMITED AND CONVERGENCE RATHER WEAK...SO ONLY EXPECTING WIDELY SCATTERED RAIN SHOWERS AS IT MOVES THROUGH. TEMPERATURE PROFILES MAY BE COLD ENOUGH FOR SOME WET SNOW TO MIX IN ACROSS HIGHER TERRAIN IN WESTERN MA. 24/12Z MODELS CONTINUE TO STRUGGLE WITH THE DETAILS OF THE SYNOPTIC PATTERN NEXT WEEK. THERE ARE SOME SIGNS THE SOLUTIONS ARE STARTING TO CONVERGE...WITH THE 12Z ECMWF COMING INTO LINE WITH THE 12Z GFS. THAT SAID...ENSEMBLES STILL SHOWING 100-140 DAM SPREAD IN THE 500 MB HEIGHTS...WHICH DOES NOT INSPIRE MUCH CONFIDENCE IN THE FORECAST DETAILS. LATEST DETERMINISTIC AND ENSEMBLE MEAN GUIDANCE ESTABLISH A FAIRLY ZONAL FLOW INTO SOUTHERN NEW ENGLAND MONDAY INTO WEDNESDAY. THIS WOULD STEER ANY STORMS EITHER TO OUR NORTH...OR TOO OUR SOUTH... DEPENDING ON WHERE IT ORIGINATED. LEANED TOWARD A CONSENSUS MODEL BLEND TO HELP IRON OUT THESE DIFFERENCES FOR NOW. THIS WOULD BRING A CHANCE FOR PRECIPITATION TO SOUTHERN NEW ENGLAND DURING THIS TIME PERIOD. THERMAL PROFILES SUGGEST THE POSSIBILITY FOR LIGHT SNOW ACROSS MUCH OF SOUTHERN NEW ENGLAND...WITH RAIN MORE LIKELY CLOSER TO THE SOUTH COAST. THIS IS SEVERAL DAYS AWAY...WITH LOW CONFIDENCE IN THE DETAILS. LOW LEVEL TEMPERATURES LOOK A BIT WARM FOR ANY SIGNIFICANT ACCUMULATIONS...ESPECIALLY FROM THE MASS PIKE TO THE SOUTH COAST. WE NEED TO SEE HOW LARGER SCALE FEATURES WILL BE RESOLVED OVER THE NEXT FEW DAYS. && .AVIATION /22Z WEDNESDAY 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 THURSDAY NIGHT/... THROUGH 00Z...MODERATE CONFIDENCE. WIDESPREAD IFR-LIFR CIGS/VSBYS WITH BANDS OF RAIN AND AREAS OF FOG. VSBYS MAY IMPROVE TO MVFR OR LOCALLY VFR AFTER 20Z AS HEAVIER RAIN MOVES INTO RI/SE MA/NE CT. S WINDS WILL ALSO INCREASE AS WARM FRONT MOVES SLOWLY N. LLWS ON INCREASING S WINDS AT 40-50 KT AT 2KFT AFTER 21Z. TONIGHT...MODERATE CONFIDENCE. EXPECT IFR VSBYS/LIFR CIGS IN RAIN...HEAVY AT TIMES...ALONG WITH ISOLD TSTMS. VSBYS IMPROVE TO MVFR-LOW END VFR IN HEAVIER RAIN MAINLY AFTER MIDNIGHT. CIGS MAY IMPROVE ACROSS CT VALLEY AFTER 09Z AS RAIN BEGINS TO SHIFT E. S-SE SURFACE WIND GUSTS UP TO 25-30 KT. LLWS ON S WINDS AT 50-60 KT AT 2KFT. ANY TSTM MAY CAUSE BRIEF WIND GUSTS UP TO 40 KT...BEST CHANCE ACROSS RI/SE MA. THURSDAY...MODERATE CONFIDENCE. IFR-LIFR CIGS/MVFR-VFR VSBYS IMPROVE TO VFR FROM W-E AS RAIN MOVES OFFSHORE. SW WINDS GUSTING UP TO 25-30 KT...SHIFTING TO W BY MIDDAY. LOW CHANCE FOR GUSTS UP TO 40 KT ACROSS THE HIGHER INTERIOR TERRAIN. THURSDAY NIGHT...HIGH CONFIDENCE. VFR. W WINDS GUSTING TO 25-30 KT EARLY...HIGHEST ALONG COAST... THEN DIMINISHING AFTER MIDNIGHT. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...FRIDAY THROUGH MONDAY... FRIDAY AND SATURDAY...HIGH CONFIDENCE VFR. SUNDAY...MODERATE CONFIDENCE. MVFR POSSIBLE IN ISOLATED RAIN SHOWERS. MONDAY...MODERATE CONFIDENCE. MAINLY VFR. LOWER CONDITIONS SOUTH OF NEW ENGLAND. LOW PROBABILITY THESE LOWER CONDITIONS MOVE FARTHER NORTH INTO SOUTHERN 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 THURSDAY NIGHT/...HIGH CONFIDENCE. TONIGHT...STRONG S-SE LOW LEVEL JET PASSES ACROSS THE WATERS THROUGH TONIGHT. LOW LEVEL INVERSION IN PLACE THROUGH 900 HPA SO WILL BE TOUGH TO MIX THE BULK DOWN. WILL SEE GUSTS UP TO 25-30 KT ON THE OUTER WATERS...INCREASING TO 35 KT S AND E OF NANTUCKET TOWARD DAYBREAK. HAVE ISSUED GALES FOR THE OUTER WATERS. MARGINAL CONDITIONS FOR GALES ON NARRAGANSETT BAY SO BACKED OFF THE STRONG SMALL CRAFT. VSBYS REDUCED IN PATCHY FOG AND RAIN. ISOLD TSTMS POSSIBLE OVERNIGHT. THURSDAY...COLD FRONT MOVES OFFSHORE BY MIDDAY. WINDS SHIFT TO W-SW AND INCREASE...GUSTS UP TO 40 KT ON THE OUTER WATERS. HAVE CONVERTED GALE WATCHES FOR SOUTHERN BAYS AND SOUNDS TO WARNINGS WITH GUSTS TO 35 KT. REMAINING WATERS HAVE SMALL CRAFTS. THURSDAY NIGHT...GALE FORCE W WINDS EARLY THU NIGHT WILL DIMINISH TO SMALL CRAFT CRITERIA OVERNIGHT. SMALL CRAFT WINDS ON BOSTON HARBOR/NARRAGANSETT BAY WILL DIMINISH OVERNIGHT. OUTLOOK...FRIDAY THROUGH MONDAY...MODERATE CONFIDENCE. WINDS GRADUALLY DIMINISH FRIDAY...WITH SEAS ALSO SLOWLY SUBSIDING INTO SATURDAY AS A HIGH PRESSURE BUILDS OVER THE MID ATLANTIC STATES. A WEAKENING COLD FRONT MAY BRING AN ISOLATED SHOWER OR TWO AS IT DROPS THROUGH NEW ENGLAND SUNDAY. WINDS AND SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY LEVELS ACROSS ALL BUT THE OUTERMOST COASTAL WATERS FROM MIDDAY SATURDAY INTO MONDAY. MODERATE PROBABILITY OF 5 FOOT SEAS ACROSS THE OUTERMOST COASTAL WATERS...PARTICULARLY SOUTH AND EAST OF NANTUCKET.
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&& .TIDES/COASTAL FLOODING...
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NOW THAT WE ARE PAST THE AFTERNOON HIGH TIDE...THE COASTAL FLOOD ADVISORY WAS CANCELED. THE HIGH TIDES CHRISTMAS MORNING WILL BE JUST AS HIGH AS THOSE TODAY. HOWEVER...WE ARE EXPECTING AN OFFSHORE WIND BY THEN...SO THE RISK FOR COASTAL FLOODING WOULD BE EVEN LOWER THAN WHAT IT WAS TODAY.
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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...FLOOD WATCH THROUGH THURSDAY MORNING FOR CTZ002>004. MA...FLOOD WATCH THROUGH THURSDAY MORNING FOR MAZ002>022-026. WIND ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST THURSDAY FOR MAZ013-016>021. WIND ADVISORY FROM 1 AM TO 9 AM EST THURSDAY FOR MAZ022>024. RI...FLOOD WATCH THROUGH THURSDAY MORNING FOR RIZ001>007. WIND ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST THURSDAY FOR RIZ002-004-005-007. MARINE...GALE WARNING FROM 10 AM TO 9 PM EST THURSDAY FOR ANZ232>234. SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT EST THURSDAY NIGHT FOR ANZ230. SMALL CRAFT ADVISORY UNTIL 5 AM EST FRIDAY FOR ANZ231. SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO MIDNIGHT EST THURSDAY NIGHT FOR ANZ236. GALE WARNING FROM 9 AM TO 9 PM EST THURSDAY FOR ANZ235-237. GALE WARNING FROM 9 AM THURSDAY TO MIDNIGHT EST THURSDAY NIGHT FOR ANZ250. SMALL CRAFT ADVISORY UNTIL 4 AM EST FRIDAY FOR ANZ251. GALE WARNING FROM 6 AM THURSDAY TO MIDNIGHT EST THURSDAY NIGHT FOR ANZ254>256.
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&& $$ SYNOPSIS...BELK/EVT NEAR TERM...EVT SHORT TERM...EVT LONG TERM...BELK AVIATION...BELK/EVT MARINE...BELK/EVT TIDES/COASTAL FLOODING...BELK CLIMATE...STAFF

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