Area Forecast Discussion
Issued by NWS Boston, MA

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921 FXUS61 KBOX 060320 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1020 PM EST FRI FEB 5 2016 .SYNOPSIS... HIGH PRESSURE BRINGS DRY WEATHER THIS WEEKEND WITH ABOVE NORMAL TEMPERATURES BY SUNDAY. A PERIOD OR TWO OF ACCUMULATING SNOW IS LIKELY MONDAY INTO WEDNESDAY ESPECIALLY ACROSS EASTERN MA...BUT ITS UNCERTAIN IF THIS WILL MAINLY BE A NUISANCE EVENT OR A SIGNIFICANT WINTER STORM. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 1030 PM UPDATE... NO MAJOR CHANGES TO THE ONGOING FORECAST. CONTINUE TO MONITOR TEMPS WHICH CONTINUE TO FALL TONIGHT. WINDS ARE STILL A BIT GUSTY SO THAT HAS SLOWED RADIATION COOLING A BIT. OTHERWISE LIGHT WINDS AND CLEAR SKIES TONIGHT AND QUIET WEATHER. 7 PM UPDATE... ALL WINTER WEATHER HEADLINES HAVE BEEN DROPPED. THE LAST OF THE LIGHT SNOW WILL COME TO AN END BY 8 PM ACROSS THE OUTER-CAPE AND NANTUCKET. OTHERWISE...SKIES HAVE BECOME MOSTLY CLEAR ACROSS THE REST OF THE REGION AND THIS WILL OCCUR ACROSS THE CAPE/ISLANDS OVER THE NEXT FEW HOURS. WINDS WILL ALSO CONTINUE TO DIMINISH ACROSS THE REGION AS PRESSURE GRADIENT WEAKENS. FRESH SNOW COVER AND DIMINISHING WIND WILL ALLOW TEMPERATURES TO FALL BELOW GUIDANCE NUMBERS IN THE OUTLYING LOCATIONS. LOWS WILL RANGE FROM BETWEEN 10 AND 15 ACROSS THE OUTLYING LOCATIONS...TO THE LOWER TO MIDDLE 20S IN THE URBAN HEAT ISLANDS OF DOWNTOWN BOSTON/PROVIDENCE. A SPECIAL WEATHER STATEMENT CONTINUES THIS EVENING...AS FALLING TEMPERATURES WILL ALLOW ANY STANDING WATER/SLUSH TO FREEZE SOLID. MOTORISTS SHOULD BE PREPARED FOR BLACK ICE. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... NOSE OF HIGH PRES BUILDS OVER FROM THE W. THE COMBINATION OF COLD ADVECTION ALOFT AND SLIGHT INCREASE IN LOW-MID LVL MOISTURE SUGGESTS SOME AFTERNOON CLOUD DEVELOPMENT...BUT LITTLE ELSE. DROPPED HIGHS A LITTLE BIT FROM CURRENT FORECASTS AS THE ADDED SNOWPACK WILL LIKELY KEEP 2M TEMPS A BIT LOWER THAN SOME OF THE GUIDANCE IS CURRENTLY SUGGESTING. EXPECT HIGHS MAINLY IN THE 30S. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... HIGHLIGHTS... * DRY WITH RELATIVELY MILD TEMPS SUN * PERIOD OR TWO OF ACCUMULATING SNOW LIKELY MON-WED ESPECIALLY COAST * UNCERTAIN IF MON-WED IS NUISANCE SNOW OR SIGNIFICANT WINTER STORM DETAILS... SATURDAY NIGHT AND SUNDAY... WEAK RIDGE OF HIGH PRESSURE WILL RESULT IN DRY WEATHER. LOW TEMPS SAT NIGHT MAINLY IN THE 20S...BUT SOME UPPER TEENS POSSIBLE ACROSS THE NORMALLY COLDER OUTLYING LOCATIONS. PLENTY OF SUNSHINE ON SUNDAY AND WESTERLY FLOW SHOULD ALLOW MUCH OF THE REGION TO SEE HIGHS WELL INTO THE 40S. LATE SUNDAY NIGHT THROUGH WEDNESDAY... EXTREMELY COMPLEX AND DIFFICULT FORECAST OVER THIS TIME PERIOD. A COUPLE OF POTENT SHORTWAVES WILL CARVE OUT A DEEP EAST COAST TROUGH. THERE IS SO MUCH ENERGY IN THE FLOW THAT THE MODELS ARE GOING TO HAVE A TOUGH TIME ON RESOLVING WHAT EXACTLY UNFOLDS. FIRST THING IS FIRST...AN INITIAL SHORTWAVE WILL EMERGE OFF THE SOUTHEAST COAST AND RAPIDLY INTENSIFY AS IT MOVES NORTHEAST. CURRENT INDICATIONS TAKE THE STORM SOUTHEAST OF THE BENCHMARK. NOW OF COURSE THAT IS 72+ HOURS OUT...SO A TRACK CLOSER TO THE COAST IS CERTAINLY POSSIBLE AND WILL NEED TO BE WATCHED. HOWEVER...EVEN IF THE STORM PASSES WELL SOUTHEAST OF THE BENCHMARK...MAY STILL END UP WITH A LIGHT TO MODERATE SNOW EVENT ESPECIALLY ON THE COAST. THIS STORM LOOKS TO HAVE A FAIRLY BROAD CIRCULATION WITH 35 TO 50 KNOTS OF ENE FLOW AT 850 MB...SO ACCUMULATING SNOW IS LIKELY FOR AT LEAST THE COASTAL PLAIN. ALSO...SOME LAND/SEA INTERFACE AND OCEAN ENHANCEMENT MAY OCCUR IN EASTERN MA. A SECOND POTENT SHORTWAVE WILL DROP DOWN FROM THE GREAT LAKES. THIS WILL ALLOW LOW PRESSURE TO DEVELOP OFF THE MID ATLANTIC COAST AND TRACK NORTHEAST TUE INTO EARLY WED. A LOT OF WHAT HAPPENS WITH THIS SYSTEM WILL BE AFFECTED BY THE STRENGTH/TRACK OF THE FIRST SYSTEM ON MONDAY. THERE ARE A WIDE RANGE OF POSSIBILITIES...FROM A GLANCING BLOW...TO A STRONG NOREASTER AND EVEN AN INVERTED TROUGH SETUP. TO SUM UP...THE MAIN IDEA IS THAT WE ARE LIKELY TO RECEIVE AT LEAST SOME SNOW AT TIMES MONDAY INTO WED. WHETHER OR NOT WE SEE A SIGNIFICANT WINTER STORM REMAINS TO BE SEEN...BUT AS MENTIONED IN THE PREVIOUS PARAGRAPHS ALL OPTIONS ARE ON THE TABLE. WE ARE LIKELY TO SEE AT LEAST SOME ACCUMULATING SNOW ESPECIALLY ALONG THE COAST. THURSDAY AND FRIDAY... LOTS OF UNCERTAINTY OVER THIS TIME FRAME. WILL HAVE TO WATCH A WAVE OR TWO OF LOW PRESSURE THAT MAY END UP BRINGING A BIT MORE SNOW...BUT MUCH OF THIS PERIOD MAY END UP DRY. GIVEN LOW CONFIDENCE...WILL KEEP POPS AT SLIGHT CHANCE FOR NOW. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SATURDAY/... TONIGHT...HIGH CONFIDENCE. LINGERING SNOW EXITS THE OUTER-CAPE/NANTUCKET BY 01Z WITH CONDITIONS IMPROVING IN THOSE LOCATIONS TO VFR BY 02Z. OTHERWISE...VFR CONDITIONS TONIGHT. ANY UNTREATED AND WET RUNWAYS WILL FREEZE AS TEMPERATURES DROP. WIND GUSTS REMAIN N-NW BUT DIMINISH THROUGH THE OVERNIGHT HOURS. TOMORROW...HIGH CONFIDENCE. MAINLY VFR. WINDS SHIFT TO THE SW...BUT SHOULD REMAIN AROUND 10 KT OR LESS. KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS...TIMING MAY BE OFF A BIT. KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS....TIMING MAY BE OFF A BIT. OUTLOOK /SATURDAY NIGHT THROUGH WEDNESDAY/... SATURDAY NIGHT AND SUNDAY...HIGH CONFIDENCE IN VFR CONDITIONS. MONDAY THROUGH WEDNESDAY...LOW CONFIDENCE ESPECIALLY ON TIMING. PERIOD OR TWO OF SNOW LIKELY IN THIS TIME FRAME...SO WILL PROBABLY SEE SOME IFR CONDITIONS ESPECIALLY ALONG THE COAST ON MON. NORTHEAST WIND GUSTS OF 30 TO 40 KNOTS LIKELY ON MONDAY ALONG THE COAST. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SATURDAY/...HIGH CONFIDENCE. STRONG NORTHWEST WINDS WILL DISSIPATE THROUGH THE LATE EVENING HOURS SUCH THAT MOST GALE WARNINGS CAN BE DROPPED BY ABOUT MIDNIGHT. SMALL CRAFT ADVISORIES WILL HAVE TO FOLLOW...BECAUSE EVEN THOUGH WINDS WILL DROP BELOW THRESHOLDS...HIGH SEAS OF 10-12 FT HAVE DEVELOPED AND WILL LINGER WELL INTO THE DAY TOMORROW. SO...EXPECT SMALL CRAFT ADVISORY...MAINLY FOR HAZARDOUS SEAS TO FOLLOW. OUTLOOK /SATURDAY NIGHT THROUGH WEDNESDAY/... SATURDAY NIGHT AND SUNDAY...HIGH CONFIDENCE. LEFT OVER 5 FOOT SWELL MAY LINGER INTO EARLY SUNDAY MORNING ACROSS OUR EASTERN OUTER- WATERS. OTHERWISE...WINDS/SEAS WILL BE BELOW SMALL CRAFT ADVISORY THRESHOLDS WITH A WEAK RIDGE OF HIGH PRESSURE IN CONTROL. MONDAY...MODERATE CONFIDENCE. GALE FORCE NORTHEAST WIND GUSTS LIKELY AS A RAPIDLY DEEPENING LOW PRESSURE SYSTEM LIKELY TRACKS SOUTHEAST OF THE BENCHMARK. THERE IS A LOW PROBABILITY FOR A PERIOD OF STORM FORCE WIND GUSTS IF THAT SYSTEM TRACKS CLOSER TO THE COAST THAN CURRENTLY EXPECTED. SEAS LIKELY BUILD TO AT LEAST 15 FEET ACROSS OUR EASTERN OUTER-WATERS WITH LONG NORTHEAST FETCH AND GOOD MIXING. TUESDAY AND WEDNESDAY...LOW CONFIDENCE. AT THE VERY LEAST NORTHEAST SMALL CRAFT WIND GUSTS AND HIGH SEAS WILL CONTINUE INTO TUE EVENING. HOWEVER...POTENTIAL FOR STRONGER WIND GUSTS DEPENDING ON STRENGTH AND LOCATION OF ANOTHER LOW PRESSURE SYSTEM. BY WEDNESDAY WIND GUSTS AND SEAS ARE QUITE UNCERTAIN...DEPENDING ON WHAT HAPPENS WITH THAT SECOND LOW PRESSURE SYSTEM. && .TIDES/COASTAL FLOODING... MONDAY... THERE IS A FAIRLY HIGH ASTRO TIDE OF 11.2 IN BOSTON LATE MONDAY MORNING. NORTHEAST WIND GUSTS OF 30 TO 40 KNOTS FROM LARGE CIRCULATION OF THE INTENSIFYING OCEAN STORM WILL LIKELY RESULT IN A 1 TO 1.5 SURGE. SEAS SHOULD BE BUILT UP TO BETWEEN 10 AND 15 FEET BY THEN...SO FEEL THERE IS A DECENT SHOT FOR POCKETS OF MINOR COASTAL FLOODING ALONG EASTERN MA COAST. THERE IS A LOW RISK FOR POCKETS OF MODERATE COASTAL FLOODING...IF THE STORMS ENDS UP A BIT FASTER AND TRACKING FURTHER WEST THAN CURRENT GUIDANCE INDICATES. MONDAY NIGHT AND TUESDAY... MAIN CONCERN IS IF WE END UP WITH A SECOND AREA OF STRONG LOW PRESSURE TRACKING UP THE COAST...WHICH COULD IMPACT ADDITIONAL HIGH TIDE CYCLES. LARGE SPREAD IN THE GUIDANCE ON WHETHER OR NOT THIS HAPPENS. IF SO...WILL HAVE TO WATCH THE TUESDAY NOON HIGH TIDE CYCLE ACROSS EASTERN MA AS BOSTON HAS AN 11.5 ASTRO TIDE. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST SATURDAY FOR ANZ231>235- 237. SMALL CRAFT ADVISORY UNTIL 1 PM EST SATURDAY FOR ANZ250. SMALL CRAFT ADVISORY UNTIL 7 AM EST SATURDAY FOR ANZ251-256. GALE WARNING UNTIL 2 AM EST SATURDAY FOR ANZ254-255. && $$ SYNOPSIS...FRANK/DOODY NEAR TERM...FRANK/DUNTEN SHORT TERM...DOODY LONG TERM...FRANK AVIATION...FRANK/DOODY MARINE...FRANK/DOODY TIDES/COASTAL FLOODING...

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