Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 220816 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 316 AM EST SAT NOV 22 2014 .SYNOPSIS...
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TEMPERATURES MODERATE TODAY ON GUSTY SOUTHWEST WINDS. THIS WILL BE FOLLOWED BY A SIGNIFICANT WARM UP SUNDAY AND ESPECIALLY MONDAY...BUT WITH A PERIOD OF RAIN SUNDAY NIGHT AND MONDAY. DRY AND COOLER TUESDAY...THEN A COASTAL STORM MAY AFFECT SOUTHERN NEW ENGLAND WEDNESDAY AND WEDNESDAY NIGHT BUT THE TRACK IS STILL UNCERTAIN. TURNING COLDER INTO THE END OF THE WEEK.
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&& .NEAR TERM /THROUGH TODAY/...
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HIGH PRES OFF THE MID ATLC COAST WILL RESULT IN DECENT WARM ADVECTION TO DEVELOP TODAY. SUNSHINE WILL GIVE WAY TO INCREASING MID/HIGH CLOUDS IN THE AFTERNOON AS MID LEVEL MOISTURE INCREASES...BUT NO PRECIP EXPECTED AS LOW LEVELS REMAIN QUITE DRY. AFTER A COLD START TO THE DAY TEMPS WILL RECOVER NICELY BUT STILL SEVERAL DEGREES BELOW NORMAL. MAXES WILL RANGE FROM THE MID 30S TO LOWER 40S WITH MID 40S OVER THE CAPE/ISLANDS. LOW LEVEL JET DEVELOPS ACROSS THE REGION IN THE AFTERNOON WHICH WILL LEAD TO GUSTY SW WINDS DEVELOPING WITH GUSTS TO 25-35 MPH...MAINLY IN THE COASTAL PLAIN. STRONGEST WINDS WILL BE ON THE CAPE/ISLANDS.
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&& .SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/...
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TONIGHT... A WEAK SHORTWAVE WILL BE MOVING INTO THE REGION AND WHILE MOISTURE IN THE COLUMN DEEPENS IT IS STILL SOMEWHAT DRY IN THE LOW LEVELS. A FEW SHOWERS ARE POSSIBLE...ESPECIALLY N ZONES WHERE LOW LEVEL MOISTURE IS GREATER BUT ANY PRECIP WILL BE SPOTTY AND VERY LIGHT. THE MAIN CONCERN IS FOR ISOLATED POCKETS OF LIGHT FREEZING RAIN IN CENTRAL/W MA AND SW NH IF ANY PRECIP DEVELOPS AS TEMPS EXPECTED TO COOL TO NEAR FREEZING TONIGHT WHILE TEMPS ALOFT WARM WELL ABOVE FREEZING. THIS IS NOT A CERTAINTY AS IT COULD REMAIN MOSTLY DRY AND WE WILL HAVE ONLY CHC POPS. TEMPS WILL HOLD NEARLY STEADY IN THE 30S TONIGHT ACROSS MUCH OF THE REGION AND NEAR 30 DEGREES NW...BUT RISING INTO THE 40S S COAST AS GUSTY SW WINDS CONTINUE. IN FACT...COULD SEE GUSTS TO 40 MPH ON CAPE/ISLANDS. SUNDAY... WEAK SFC RIDGING DEVELOPS ACROSS SNE AS MOISTURE GRADUALLY DECREASES. EXPECT A DRY AND MILD DAY WITH MORNING CLOUDS GIVING WAY TO PARTIAL SUNSHINE. USED A BLEND OF AVAILABLE GUIDANCE FOR TEMPS WITH MAXES IN THE LOW TO MID 50S...EXCEPT UPPER 40S NW HIGHER TERRAIN.
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&& .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
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*/ HIGHLIGHTS... - TURNING WARMER AND WET MONDAY - A POSSIBLE MIDWEEK STORM...ESPECIALLY FOR SE NEW ENGLAND - LOOKING COLDER INTO THANKSGIVING */ OVERVIEW AND MODEL CONSENSUS... TRENDING +AO/NAO WITH NEAR-NEUTRAL PNA SUGGESTS A MORE PROGRESSIVE PATTERN AND MILD. NO SURPRISE TO SEE A LACK OF DEEP CLOSED-LOW H5 DISTURBANCES...THOUGH AN ACTIVE PATTERN WITH ABUNDANCE OF PACIFIC- ORIGIN WAVES MAINTAINING TROUGHING BETWEEN SECTORS OF ABOVE-AVERAGE OCEAN TEMPERATURES OVER THE NE-PACIFIC AND NW-ATLANTIC. SOME OF THOSE WAVES ARE WELL OUT IN THE PACIFIC AND HAVE NOT EVEN BEEN SAMPLED. THE WAVE ASSOCIATED WITH THE WINTER-STORM POTENTIAL FOR THE MIDWEEK / THANKSGIVING PERIOD IS JUST S OF THE FURTHEST E ALEUTAIN ISLANDS OF ALASKA. NOTING THIS...HAVE HIGHEST CONFIDENCE THROUGH EARLY-NEXT WEEK WITH THE FORECAST...BUT LOW CONFIDENCE FOR A POTENTIAL MIDWEEK STORM. WILL HIT UP THE DETAILS BELOW. SUNDAY NIGHT... WARM-FRONT AND ACCOMPANYING BROADSCALE LIFT AHEAD OF A DEEPENING LOW ACROSS THE C-CONUS THROUGH THE GREAT LAKES REGION BECOMES THE FOCUS FOR RAIN ACROSS THE REGION. NON-DIURNAL WARMING TREND OVERNIGHT. ALL- RAIN EVENT. MAIN CONCERNS ARE WITH BOTH WINDS AND RAIN. WITH WINDS: STRONG LOW-LEVEL JET CENTERED AROUND MONDAY MORNING WITH WINDS 1-2 KFT AGL MODEL-CONSENSUS AVERAGING AROUND 50 MPH /45 KTS/. SUGGESTED BOUNDARY-LAYER DECOUPLING BENEATH MUCH WARMER AIR BETWEEN H925-85. BUT IF 2M TEMPERATURES ARE WARMER AS FORECAST FOR SUNDAY COULD BE WARMER SUNDAY NIGHT AIDING IN LOW-LEVEL MIXING. ALSO NEED TO CONSIDER ANY HEAVY RAIN WHICH COULD ALSO AID WITH DRAGGING FASTER MOMENTUM TO THE SURFACE. OVERALL: MAIN CONCERN ACROSS SE NEW ENGLAND AND HIGH TERRAIN ABOVE 1 KFT. WIND ADVISORIES MAY BE NECESSARY. CIPS ANALOG GUIDANCE HAS JUST ABOVE 50-PERCENT FOR WINDS > 35 MPH. WITH RAIN: BROADSCALE ASCENT OF THE WARM-CONVEYER-BELT WITH PWATS UP TO 1.5-INCHES AND ANOMALOUS HIGH-THETAE AIR. CONVERGENCE ALONG THE NOSE OF THE LOW-LEVEL JET TO THE PARENT WARM-FRONT. EXPECT A BROAD NW-SE BAND OF RAIN WITH PERHAPS AN EMBEDDED LINE OF HEAVIER RAIN. IT MOVES THROUGH NOTABLY QUICK. MODEL-CONSENSUS AVERAGE RAIN AMOUNTS ARE AROUND 0.50 - 0.75 INCHES. AM NOT EXPECTING ANY FLOOD ISSUES. INTO MONDAY... RAINS FOR THE MORNING...IMPROVING AFTERNOON. IF WE CLEAR AS H925 TEMPERATURES WARM TO +14C THEN WE COULD POSSIBLY SEE HIGHS INTO THE MID- TO UPPER-60S /+18C/ POSSIBLY TO NEAR 70. MODEL-CONSENSUS H925 WINDS AVERAGE AROUND 45 MPH /40 KTS/ AND WITH WARMER CONDITIONS COULD SEE THE POTENTIAL FOR MIXING OUT TO H9 AND MOMENTUM MIX-DOWN. WILL HINT AT THIS IN THE FORECAST...BUT MODERATE CONFIDENCE. MONDAY NIGHT THROUGH TUESDAY NIGHT... WILL GO WITH A FEW LINGERING SHOWERS...BUT THE MAIN PUMP OF MOISTURE SHOULD BE WELL OFFSHORE. OTHERWISE THE MAIN COLD FRONT ATTENDANT TO THE DEEPENING LOW LIFTING THROUGH THE GREAT LAKES REGION SWEEPS ACROSS NEW ENGLAND. EXPECTING DRY AND COOLER WEATHER FOR TUESDAY... PERHAPS CONTINUING INTO TUESDAY NIGHT. WEDNESDAY AND BEYOND... JUST TOO EARLY TO SAY. LOTS OF UNCERTAINTY AS ENSEMBLE MEMBERS VARY CONSIDERABLY WITH SURFACE LOW CENTERS AROUND THE ENSEMBLE MEAN WHICH KEY UPON A LOW SE OF THE 40N / 70W BENCHMARK AROUND WEDNESDAY NIGHT. HAVE CONCERNS FOR SE NEW ENGLAND WHICH COULD SEE THE GREATEST IMPACT WHILE NOTING A RIDGE OF HIGH PRESSURE OVER S-CANADA /WITH THE CENTER OVER THE C-CONUS/. THE GFS-UPGRADED /T1534/ IS A FAR OUTLIER AND IS NOT CONSIDERED WITH THIS FORECAST. EVALUATING SYNOPTICS...THIS DOES NOT APPEAR TO BE A COASTAL STORM BUT MORE OF A WAVE LOW ALONG THE OFFSHORE STALLED FRONT. AS BEEN THE CASE THIS YEAR...COLD AIR HAS BEEN PLUNGING INTO THE CENTRAL CONUS BUT ITS TRUE BITE REMAINS MAINLY N/W OF OUR REGION. DO HAVE SOME CONFIDENCE THAT THE WAVE LOW WILL HUG CLOSER TO THE COAST. THEN IT COMES TO BREAKING DOWN TIMING / ASSOCIATED DYNAMICS / THERMAL FIELDS WHICH RIGHT NOW ARE AGAIN TOO EARLY TO DIAGNOSE. THERE HAS BEEN A CONSISTENT SIGNAL. STORM BEARS WATCHING. EXPECTING A RETURN OF ARCTIC AIR BEHIND WHATEVER MIDWEEK SYSTEM THAT MAY EMERGE. DAY 6-8 CIPS ANALOGS HAVE HIGH PROBABILITIES FOR BELOW- NORMAL TEMPERATURES FOR THE SE-CONUS INTO THE OHIO-RIVER VALLEY CENTERED AROUND THE LATE-THANKSGIVING WEEK PERIOD. EC ENSEMBLES AT H85 HAVE THE FREEZING MARK PLUNGING TO NEARLY THE GULF COAST...WITH -10C AIR INTO NEW ENGLAND BY NEXT WEEKEND.
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&& .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM /THROUGH SUNDAY/...HIGH CONFIDENCE. TODAY...VFR. MID LEVEL CIGS DEVELOPING IN THE AFTERNOON. INCREASING SW WINDS IN THE AFTERNOON WITH GUSTS TO 25-30 KT IN THE COASTAL PLAIN. TONIGHT...MAINLY LOW-END VFR CIGS DEVELOPING BUT LOW PROB FOR MVFR WITH A FEW SHOWERS EXPECTED. ISOLATED POCKETS OF -FZRA POSSIBLE IN W MA AND SW NH. ANY ICING WILL BE VERY LIGHT. SW WIND GUSTS TO 25-30 KT NEAR THE COAST...POSSIBLY UP TO 35 KT CAPE/ISLANDS. SUNDAY...VFR CIGS. SW GUSTS TO 25 KT CAPE/ISLANDS IN THE MORNING...THEN DIMINISHING WIND. KBOS TERMINAL...HIGH CONFIDENCE. EXPECT VFR CIGS TONIGHT BUT A FEW SHOWERS POSSIBLE. SW GUSTS 25-30 KT DEVELOPING THIS AFTERNOON. KBDL TERMINAL...HIGH CONFIDENCE. A FEW SHOWERS POSSIBLE TONIGHT BUT DO NOT ANTICIPATE ANY -FZRA. LOW PROB FOR BRIEF MVFR CIGS TONIGHT. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY. SUNDAY NIGHT INTO MONDAY...MODERATE CONFIDENCE. CONDITIONS DETERIORATE MVFR-LIFR SUNDAY NIGHT INTO MONDAY MORNING WITH +RA AND STRONG S-WINDS WITH GUSTS AROUND 30 KTS POSSIBLE... OTHERWISE LLWS IMPACTS WITH 50 KT S-WINDS 2 KFT AGL. CONDITIONS IMPROVE BY MIDDAY...BUT COULD SEE CONTINUED SW-WINDS AROUND 25 KTS. MONDAY NIGHT THROUGH TUESDAY...MODERATE CONFIDENCE. W-FLOW WITH MAINLY VFR. WEDNESDAY...LOW CONFIDENCE. AN OFFSHORE STORM SYSTEM COULD BRING SIGNIFICANT IMPACTS ESPECIALLY TO THE SE-TERMINALS. && .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 SUNDAY/...HIGH CONFIDENCE. LOW LEVEL JET DEVELOPS ACROSS THE REGION THIS AFTERNOON INTO TONIGHT. WITH STILL COOL AIR OVER WARMER SST...MIXING OVER THE WATER WILL BE SUFFICIENT FOR GUSTS TO 35-40 KT DEVELOPING THIS AFTERNOON INTO TONIGHT...WITH STRONGEST WINDS E AND S OF CAPE COD. WE CONVERTED THE GALE WATCH TO WARNINGS...WITH SCA FOR BOS HARBOR...NARRAGANSETT BAY AND MASS BAY. SEAS BUILD TO 10 FEET TONIGHT OVER SOUTHERN WATERS. SUNDAY...GUSTY SW WINDS 25-30 KT IN THE MORNING WILL BE DIMINISHING THROUGH THE AFTERNOON AND DROPPING BELOW 20 KT. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY. SUNDAY NIGHT INTO MONDAY...MODERATE CONFIDENCE. CONDITIONS DETERIORATE INTO MONDAY MORNING WITH RAIN OVER THE WATERS AND EMBEDDED HEAVIER SHOWERS. VISIBILITY IMPACTS POSSIBLE. WINDS INCREASING OUT OF THE S. GUSTS EXCEEDING GALE FORCE APPEAR LIKELY. WAVES SUBSEQUENTLY INCREASING TO 10 FEET ON THE OUTER WATERS. MONDAY NIGHT THROUGH TUESDAY...MODERATE CONFIDENCE. WINDS TURNING SW REMAINING BLUSTERY WITH GUSTS EXCEEDING 25 KTS. WAVES MAINTAINED WITH HEIGHTS OF 8 TO 10 FEET ON THE OUTER WATERS. WEDNESDAY...LOW CONFIDENCE. AN OFFSHORE STORM SYSTEM COULD BRING SIGNIFICANT IMPACTS TO THE WATERS YET DETAILS UNCERTAIN AT THIS TIME.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...GALE WARNING FROM 3 PM THIS AFTERNOON TO 4 AM EST SUNDAY FOR ANZ231-232. GALE WARNING FROM 3 PM THIS AFTERNOON TO 1 AM EST SUNDAY FOR ANZ233>235-237-256. SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 6 AM EST SUNDAY FOR ANZ230-236-251. GALE WARNING FROM 3 PM THIS AFTERNOON TO 6 AM EST SUNDAY FOR ANZ250-254-255.
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&& $$ SYNOPSIS...KJC/DOODY NEAR TERM...KJC SHORT TERM...KJC LONG TERM...DOODY AVIATION...KJC/DOODY MARINE...KJC/DOODY

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