Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 301005 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 505 AM EST FRI JAN 30 2015 .SYNOPSIS...
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LOW PRESSURE WILL WEAKEN OVER SOUTHERN QUEBEC AS A SECONDARY LOW DEVELOPS ALONG THE SOUTHERN NEW ENGLAND COAST THIS AFTERNOON AND INTENSIFIES OVER THE GULF OF MAINE TONIGHT BRINGING WITH IT A PERIOD OF SNOW FOR THE FORECAST AREA. BLUSTERY AND VERY COLD CONDITIONS ARE EXPECTED THIS WEEKEND. WATCHING FOR THE POTENTIAL OF NOREASTERS NEXT WEEK...ONE POSSIBLE SUNDAY NIGHT INTO MONDAY AND ANOTHER POSSIBLE WEDNESDAY NIGHT INTO THURSDAY. LOW CONFIDENCE ON BOTH.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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AREA OF LIGHT SNOW MOVING ACROSS SNE EARLY THIS MORNING. PRECIP NOT VERY ORGANIZED AND ASSOCD WITH WEAK OVERRUNNING AHEAD OF PARENT LOW ACROSS THE EASTERN LAKES. AMPLIFYING MID LEVEL TROF ACROSS THE GT LAKES BECOMES NEG TILTED AS IT REACHES THE COAST LATE TODAY. ASSOCD HEIGHT FALL CENTER AND SHORTWAVE ENERGY WILL RESULT IN PARENT LOW FILLING ACROSS NORTHERN NEW ENG WITH CYCLOGENESIS NEAR OR SOUTH OF CAPE COD LATER THIS AFTERNOON. EXPECT A PERIOD OF MAINLY LIGHT SNOW TODAY AHEAD OF THE OPEN MID LEVEL WAVE WHICH SHOULD TAPER OFF THIS AFTERNOON ACROSS THE CT VALLEY TO THE RI COAST. WARMING BOUNDARY LAYER ALONG THE IMMEDIATE SE NEW ENG COAST WILL RESULT IN RAIN OR MIXED RAIN/SNOW FOR THE CAPE AND ISLANDS. USED A BLEND OF MODEL QPF WHICH RESULTS IN SNOW ACCUM THROUGH TODAY OF 1-2 INCHES AWAY FROM THE COAST...WITH UP TO 3 INCHES NORTH CENTRAL AND NW MA. ALONG THE S COAST...EXPECT LESS THAN AN INCH.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
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TONIGHT INTO SATURDAY... NEG TILT TROF EVOLVES INTO A CLOSED MID LEVEL OVER SOUTHERN NEW ENGLAND THIS EVENING THEN IT JUMPS TO THE GULF OF MAINE LATER TONIGHT. THE SFC LOW DEEPENS RAPIDLY TONIGHT IN THE GULF OF MAINE BUT LIKELY REMAINS A BIT TOO FAR OFFSHORE TO ROTATE HEAVY SNOW BACK ACROSS SNE AS THE HEAVIER PRECIP WILL REMAIN TO THE NORTH OVER MAINE. HOWEVER...A ROBUST COMMA HEAD WILL DEVELOP TO THE WEST OF THE MID LEVEL LOW TONIGHT AND EXTEND ACROSS EASTERN NEW ENG WHICH WILL LIKELY BRING BANDS OF SNOW TO THE REGION. THE WESTWARD EXTENT OF THE SNOW TONIGHT WILL LIKELY BE ACROSS CENTRAL MA AND RI WITH THE MAIN FOCUS ACROSS E MA INCLUDING THE CAPE/ISLANDS. MAINLY DRY WEATHER EXPECTED IN THE CT VALLEY. MODELS BACKED OFF A BIT ON THE QPF SO WE HAVE LOWERED SNOW ACCUM A TAD...BUT HAVE TO WATCH NE MA AND CAPE COD WHICH WILL BE CLOSEST TO THE BEST FORCING. SNOW LINGERS ACROSS E MA INTO SAT MORNING...BEFORE GRADUALLY MOVING OUT. THE OUTER CAPE WILL BE LAST TO DRY OUT AROUND MIDDAY. OTHERWISE...CLEARING SKIES WILL DEVELOP FROM WEST TO EAST LATE MORNING THROUGH THE AFTERNOON BUT WINDY AND VERY COLD SATURDAY WITH HIGHS MOSTLY IN THE TEENS. WE KEPT THE WINTER STORM WARNING FOR ESSEX COUNTY BUT DOWNGRADED MIDDLESEX COUNTY TO AN ADVISORY. EXPANDED THE ADVISORY TO CAPE COD WHICH SHOULD GET INTO A DECENT BAND OF SNOW TONIGHT. OTHERWISE...DROPPED THE ADVISORY FOR NE CT...N RI AND ADJACENT SE MA WHERE SNOW AMOUNTS SHOULD FALL SHY OF ADVISORY CRITERIA. TOTAL SNOW ACCUM OF 4-7 EXPECTED ACROSS NE MA WITH THE MAX AMOUNTS IN ESSEX COUNTY...WITH 2-4 INCHES CENTRAL MA TO E COASTAL MA INCLUDING CAPE COD. AN INCH OR 2 POSSIBLE NEAR THE S COAST. IN ADDITION TO THE SNOWFALL TONIGHT...NORTHWEST WINDS WILL INCREASE LATE TONIGHT INTO SAT WITH GUSTS TO 40 TO 45 MPH AS LOW INTENSIFIES EAST OF MA. LOW PROB WIND GUSTS COULD REACH 50 MPH NEAR THE S COAST AND WIND ADVISORIES MAY EVENTUALLY BE NEEDED. VERY COLD AIR MOVES IN TONIGHT INTO SATURDAY COMBINED WITH GUSTY NW WINDS WILL RESULT IN DANGEROUSLY COLD WIND CHILLS OF 10 TO 20 BELOW ZERO IN CENTRAL AND WESTERN MA AND PORTIONS OF N CT WHERE WIND CHILL ADVISORIES HAVE BEEN ISSUED. WIND CHILLS 5 TO 10 BELOW IN THE COASTAL PLAIN.
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&& .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... HEADLINES... * SNOW ENDS ACROSS EASTERN AREAS EARLY SATURDAY FOLLOWED BY ARCTIC HIGH PRESSURE FOR THE REST OF THE WEEKEND * WATCHING FOR POTENTIAL NOREASTERS NEXT WEEK AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS SOUTHERN NEW ENGLAND. OCEAN STORM OFF THE MAINE COAST ON SATURDAY WILL EXIT TO THE EAST... BRINGING AN END TO ANY SNOWFALL ACROSS COASTAL LOCALES SATURDAY MORNING. IMPROVING CONDITIONS WILL OCCUR DURING THE DAY ON A BLUSTERY NW WIND FLOW AS A COLD AIRMASS MOVES INTO NEW ENGLAND FROM CANADA. THIS WILL ENSURE A VERY COLD WEEKEND WITH TEMPS RUNNING WELL BELOW AVERAGE. THE SYNOPTIC PATTERN NEXT WEEK WILL FEATURE SHORTWAVES DIVING INTO THE UPPER MIDWEST AND ACROSS NEW ENGLAND. THIS WILL ALLOW FOR POTENTIAL NOREASTERS TO DEVELOP. HOWEVER, MUCH WILL DEPEND ON HOW SHARP THE TROUGHS BECOME...WHETHER THEY BECOME NEGATIVELY TILTED AND PHASE OR NOT WITH SOUTHERN STREAM ENERGY. THERE HAVE BEEN MODEL DIFFERENCES FROM BOTH GFS/ECMWF IN TERMS OF THE STRENGTH AND TRACK OF THE LOWS SO WILL FOLLOW A BLENDED MODEL APPROACH. THE TIMING OF THESE POTENTIAL SYSTEMS LOOKS TO BE SUNDAY NIGHT AND MONDAY AND AGAIN WEDNESDAY NIGHT THROUGH THURSDAY. THESE ARE THE PERIODS TO MONITOR FOR POTENTIAL HIGH IMPACTS TO THE AREA. WHETHER OR NOT WE RECEIVE SIGNIFICANT ADDITIONAL SNOWFALL OR THESE OCEAN STORMS MISS US TO THE EAST IS JUST TOO TOUGH TO SAY WITH ANY DEGREE OF CONFIDENCE. SO STAY TUNED. FOR THE SUN NIGHT-MONDAY LOW...BOTH THE OPERATIONAL 29.12Z GFS AND ECMWF RUNS HAVE THE LOW CENTER PASSING JUST OUTSIDE THE BENCHMARK WHICH WOULD MEAN A GLANCING BLOW TO SOUTHEASTERN NEW ENGLAND...BUT STILL A PLOWABLE SNOWFALL TO EASTERN AREAS. HOWEVER, A FEW ENSEMBLE MEMBERS ARE FURTHER NORTHWEST WITH THE LOW TRACK...SO A MORE SIGNIFICANT IMPACT IS A POSSIBILITY...AS IS NO IMPACT IF THE LOW WERE TO TRACK EVEN FURTHER OFF SHORE. THE FIRST RUNS OF THE OPERATIONAL ECMWF FOR THE BLIZZARD OF 2015 DIDN`T SHOW MAJOR IMPACTS TO NEW ENGLAND UNTIL 72 HR IN ADVANCE OF THE EVENT. WE ARE STILL OUTSIDE OF THIS WINDOW...SO LOTS CAN CHANGE. TUESDAY WILL BE A LULL DAY IF THE AFOREMENTIONED LOW IMPACTS NEW ENGLAND. THEN WE LOOK TO YET ANOTHER POTENTIAL OCEAN STORM MID WEEK...WITH MODELS CENTERING ON THE WED NIGHT-THU TIMEFRAME. THE 29.12Z OPERATIONAL ECMWF IS AGGRESSIVE WITH THIS LOW...SLAMMING HEAVY SNOWS OVER THE INTERIOR WITH A SNOW TO RAIN SCENARIO FOR THE COAST. HOWEVER, THE GFS DOES NOT PHASE THE NORTHERN AND SOUTHERN STREAMS...SO IS PROGRESSIVE AND SHOWS MINIMAL IMPACTS. SO USED A MODEL BLEND AND...ONCE AGAIN...TOO EARLY TO BANK ON EITHER A HIT OR A MISS. CERTAINLY A LOT TO MONITOR CLOSELY IN THE DAYS AHEAD! && .AVIATION /08Z 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...MODERATE CONFIDENCE. THROUGH 12Z...LIGHT SNOW OVERSPREADING THE REGION WITH CONDITIONS LOWERING TO MVFR/IFR. SNOW MIXING WITH OR CHANGING TO RAIN CAPE/ISLANDS TOWARD DAYBREAK. TODAY...MVFR/IFR IN AREAS OF SNOW...WITH RAIN CAPE/ISLANDS. SNOW TAPERS OFF AND ENDS CT VALLEY TO THE RI COAST DURING THE AFTERNOON WITH MAINLY MVFR CIGS...BUT PERIODS OF SNOW CONTINUE CENTRAL AND E MA. GUSTY NW WINDS TO 25 KT DEVELOPING CT VALLEY BY LATE AFTERNOON. TONIGHT...MAIN FOCUS FOR AREAS OF SNOW AND MVFR/IFR CONDITIONS WILL BE ACROSS E MA...WITH VFR CT VALLEY. GUSTY NW WINDS DEVELOP FROM WEST TO EAST IN THE EVENING WITH GUSTS TO 30-40 KT AFTER MIDNIGHT. SATURDAY...LINGERING MVFR/IFR IN AREAS OF LIGHT SNOW ACROSS E MA AND CAPE/ISLANDS EARLY...OTHERWISE IMPROVING TO VFR WITH CLEARING SKIES FROM WEST TO EAST. GUSTY NW WINDS TO 35-40 KT. KBOS TAF...MODERATE CONFIDENCE. KBDL TAF...MODERATE CONFIDENCE. OUTLOOK /SATURDAY NIGHT THROUGH MONDAY/... SATURDAY NIGHT-SUNDAY...HIGH CONFIDENCE. VFR. NW WINDS GUSTING TO 25-35 KNOTS SATURDAY...HIGHEST ALONG THE COAST. LIGHTER WINDS SUNDAY. SUNDAY NIGHT-MONDAY...LOW CONFIDENCE. LOW PRES DEVELOPS S OF THE REGION...BUT TRACK REMAINS UNCERTAIN. TOO EARLY TO HAVE ANY CONFIDENCE ON VFR OR IFR THIS PERIOD. TUESDAY...MODERATE CONFIDENCE. IF LOW IMPACTS THE TERMINALS MONDAY, CONDITIONS WOULD BE IMPROVING ON TUE.
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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...SOUTHERLY WINDS WILL SHIFT TO W THEN NW DURING FRI AFTERNOON...WITH GUSTS TO 25 KT DEVELOPING ACROSS RI COASTAL WATERS BY LATE AFTERNOON. TONIGHT AND SATURDAY...AS LOW PRES INTENSIFIES OVER WESTERN GULF OF MAINE...GALE FORCE NW WINDS WILL DEVELOP. GUSTS TO 40-45 KT EXPECTED LATE TONIGHT INTO SAT. THE GUSTY WINDS AND ROUGH SEAS COMBINED WITH ARCTIC AIR MOVING INTO THE REGION WILL RESULT IN AREAS OF MODERATE FREEZING SPRAY OVER THE NEARSHORE WATERS SO FREEZING SPRAY ADVISORIES WERE ISSUED. SNOW REDUCES VSBY OVER EASTERN WATERS TONIGHT INTO SAT MORNING. OUTLOOK /SATURDAY NIGHT THROUGH MONDAY/...MODERATE CONFIDENCE SATURDAY NIGHT...WINDS AND SEAS WILL DIMINISH AS LOW PRESSURE DEPARTS THE AREA. SUNDAY...EXPECT WINDS TO DIMINISH BUT REMAIN AT SMALL CRAFT LEVELS...THOUGH SOME GALE GUSTS MAY LINGER ON THE EASTERN OUTER WATERS EARLY. SEAS WILL SLOWLY SUBSIDE...BUT WILL REMAIN AOA 5 FT ON THE OUTER WATERS. SUNDAY NIGHT-TUESDAY...HIGHLY DEPENDENT ON STRENGTH AND TRACK OF DEVELOPING LOW PRESSURE SOUTH OF THE REGION AND THUS A LOW CONFIDENCE FORECAST. WORSE CONDITIONS WOULD BE MONDAY WITH SLOW IMPROVEMENT ON TUESDAY.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...WINTER WEATHER ADVISORY UNTIL 8 AM EST SATURDAY FOR MAZ004-005- 012>016-018-019-026. WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 11 AM EST SATURDAY FOR MAZ002-008-009. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 8 AM EST SATURDAY FOR MAZ022. WINTER STORM WARNING UNTIL 8 AM EST SATURDAY FOR MAZ006-007. RI...NONE. MARINE...FREEZING SPRAY ADVISORY FROM 11 PM THIS EVENING TO 6 PM EST SATURDAY FOR ANZ231>235-237-250-251. GALE WARNING FROM 11 PM THIS EVENING TO 6 PM EST SATURDAY FOR ANZ232-250-254-255. GALE WARNING FROM MIDNIGHT TONIGHT TO 6 PM EST SATURDAY FOR ANZ230-231-233-234-251. GALE WARNING FROM 1 AM TO 1 PM EST SATURDAY FOR ANZ236. GALE WARNING FROM 9 PM THIS EVENING TO 6 PM EST SATURDAY FOR ANZ235-237. GALE WARNING FROM 7 PM THIS EVENING TO 6 PM EST SATURDAY FOR ANZ256.
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&& $$ SYNOPSIS...KJC NEAR TERM...KJC SHORT TERM...KJC LONG TERM...99 AVIATION...KJC/99 MARINE...KJC/99

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