Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 220841 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 341 AM EST SAT NOV 22 2014 .SYNOPSIS... 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. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 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. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... 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. && .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 LATE WEEK OVERVIEW AND MODEL PREFERENCES... 22.00Z MODEL GUIDANCE CONTINUES TO EXHIBIT GOOD AGREEMENT IN THE SYNOPTIC PATTERN THROUGH ABOUT MID WEEK. THE KEY IS A DEVELOPING LONGWAVE TROF...WHICH AXIS REMAINS WELL TO THE W ACROSS THE GREAT LAKES AND INTO THE OHIO VALLEY. THIS YIELDS CONTINUES STACKED SW FLOW THROUGH THE PERIOD...KEEPING THE BULK OF THE COLDER AIR TO THE W. THE ONE PRIMARY ISSUE STILL WITHIN THE MOST UNCERTAIN PORTION...FROM WED ONWARD...IS A NRN STREAM SHORTWAVE EJECTING OUT OF THE PACIFIC TO THE S OF THE ALLEUTIAN ISLANDS. IT IS THIS FEATURE WHICH IS STILL GENERATING A WAVE OF LOW PRES ALONG A STALLED FRONTAL BOUNDARY FROM THE MID ATLANTIC. THIS LOW PRES WOULD THEN PASS SOMEWHERE FROM THE S COAST TO WELL SE OF THE 40/70 BENCHMARK. THE ENVELOP OF POTENTIAL TRACKS START LATE WED INTO WED NIGHT...AND RANGE FROM NEAR THE CAPE COD CANAL TO WELL OFFSHORE WITH LITTLE TO NO IMPACT. THE ENSEMBLES ALL FALL IN THIS ENVELOP WHILE THE GFS IS NEAR THE E EDGE AND THE ECMWF NEAR THE W EDGE. THEREFORE...FEEL THAT A BLEND OF GUIDANCE WILL CONVEY BOTH THE UNCERTAINTY AND TAKE INTO ACCOUNT THE POTENTIAL SOLUTIONS. THIS INCLUDES THERMAL PROFILES AS THE ECMWF IS SIGNIFICANTLY WARMER THAN THE GFS. DETAILS... SUN NIGHT INTO MON... WARM OCCLUSION WILL BE MOVING THROUGH EARLY MON MORNING...THIS IS ASSOCIATED WITH PWATS BETWEEN 1.0-1.25 INCHES...MODERATE SLY LLJ AROUND 65 KT AND K-VALUES ABOVE 30. ESSENTIALLY ALL INGREDIENTS FOR WIDESPREAD RAINFALL WITH EMBEDDED HEAVIER RAIN AND CONVECTIVE ELEMENTS. TS WOULD BE ISOLATED...BUT NOT OUT OF THE QUESTION. WILL NEED TO MONITOR FOR THIS HEAVY RAIN THREAT UNTIL IT MOVES THROUGH BY ABOUT MID MORNING-MID DAY MON. WILL ALSO NEED TO MONITOR FOR STRONG WINDS THANKS TO PRECIP DRAG OR CONVECTIVE FORCING TO THE SFC AS THE 65 KT LLJ CORE IS ONLY AT ABOUT H92. NOTE MODEST INVERSION INITIALLY...BUT SOME MIXING OF THIS MOMENTUM IS NOT OUT OF THE QUESTION. SHOWERS MAY LINGER INTO THE MON NIGHT HOURS...BUT WILL BE LIGHTER AND LESS WIDESPREAD AS THE UPPER LVL IMPULSE MOVES THROUGH AND LOW-MID LVL MOISTURE REMAINS IN PLACE. TUE AND TUE NIGHT... BRIEF RIDGE OF HIGH PRES MOVES OVER FROM THE SW AND CRESTS ACROSS THE REGION. MID LVL TEMPS STILL RELATIVELY HIGH...SO EXPECT TEMPS MAINLY ABOVE NORMAL. WED AND THU... AS MENTIONED ABOVE CONFIDENCE IS LOW IN THIS PORTION OF THE FORECAST BUT WILL NEED TO MONITOR A COASTAL LOW PRES SYSTEM MOVING NE FROM THE MID ATLANTIC. DEPENDING ON THE TRACK...COULD SEE JUST SOME RAIN FOR E MA AND RI WITH THE POSSIBILITY OF A BIT OF LIGHT MIXED PRECIP TO THE INTERIOR CT/MA/SW NH...THIS IS THE E EDGE OF THE ENVELOP REPRESENTED BY THE GFS. THE ECMWF IS MUCH WARMER AND PASSES NEAR THE CANAL..BUT ALSO IS MORE DYNAMIC WITH MORE PRECIPITATION. AT THIS TIME...GIVEN THE LACK OF A BLOCKING ARCTIC HIGH AND SLIGHTLY POSITIVE AO/NAO AS THE PREVIOUS FORECASTER NOTED...FEEL THAT THERE WILL BE ENOUGH WARM AIR IN PLACE FOR RAIN/MIXED PRECIP RATHER THAN SNOW OUTRIGHT EVEN IF THE GFS OR E TRACKING ENSEMBLES VERIFY. WILL NEED TO MONITOR THIS HOWEVER...GIVEN THAT WARM AIR COULD COME IN FASTER ALOFT AND THERE WILL BE SIGNIFICANT TRAVEL FOR THE HOLIDAY. LATE NEXT WEEK-EARLY WEEKEND... THU-FRI COULD SEE BRIEF SHOT OF LIGHT PRECIP AS THE UPPER SHORTWAVE EJECTS ENE...BUT BY THIS POINT DRIER AIR IS ALREADY MOVING IN BEHIND THE COASTAL LOW. IN ANY CASE EXPECT COOLER AIR TO BEGIN TO FILTER IN TOWARD THE END OF THE WEEK.
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&& .AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
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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. 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. WSW-FLOW WITH MAINLY VFR. WEDNESDAY...LOW CONFIDENCE. AN OFFSHORE STORM SYSTEM COULD BRING SIGNIFICANT IMPACTS ESPECIALLY TO THE SE-TERMINALS.
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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 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. SOUTHERLY WINDS GUST TO AROUND 30 KT...WITH SEAS BUILDING TO ABOUT 10+ FEET ON THE SRN OCEAN WATERS. SMALL CRAFT ADVISORIES AT LEAST NEEDED. 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... 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. && $$ SYNOPSIS...KJC/DOODY NEAR TERM...KJC SHORT TERM...KJC LONG TERM...DOODY AVIATION...KJC/DOODY MARINE...KJC/DOODY

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