Area Forecast Discussion
Issued by NWS Boston, MA

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134 FXUS61 KBOX 140948 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 448 AM EST SUN FEB 14 2016 .SYNOPSIS... HISTORIC ARCTIC OUTBREAK FOR THE MODERN ERA CONTINUES THIS MORNING WITH DANGEROUSLY COLD WIND CHILLS OF 25 TO 40 BELOW. WINDS DIMINISH SOME LATER TODAY AND ESPECIALLY TONIGHT...BUT IT WILL REMAIN BITTERLY COLD. A PERIOD OF ACCUMULATING SNOW IS THEN LIKELY FOR MUCH OF REGION ESPECIALLY AWAY FROM THE COAST LATE MONDAY AFTERNOON AND EVENING...CHANGING TO RAIN BY TUESDAY MORNING. A POWERFUL STORM SYSTEM WILL LIKELY TRACK WEST OF NEW ENGLAND TUESDAY INTO TUESDAY NIGHT BRINGING HEAVY RAIN...STRONG WINDS AND WARM TEMPERATURES TO THE REGION. A TREND TOWARD DRIER AND COLDER WEATHER FOLLOWS ON WEDNESDAY AND THURSDAY. ANOTHER WEATHER SYSTEM WILL BRING SNOW AND RAIN TOWARD THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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***DANGEROUS WIND CHILLS OF 25 TO 40 BELOW ZERO THIS MORNING*** ***HISTORIC ARCTIC OUTBREAK FOR THE MODERN ERA BRINGS THE COLDEST TEMPERATURES TO BOSTON AND WORCESTER SINCE 1957*** EXTREME ARCTIC OUTBREAK FOR SOUTHERN NEW ENGLAND STANDARDS CONTINUES WITH TEMPS DOWN TO -15 IN WORCESTER AND -9 IN BOSTON AS OF 4 AM. THESE ARE THE COLDEST READINGS RECORDED AT BOTH LOCATIONS SINCE 1957! SO ITS FAIR TO SAY THAT THIS IS A HISTORIC ARCTIC OUTBREAK FOR THE MODERN ERA. A NEW RECORD WAS ALSO BROKEN WITH THE FEB 14/00Z UPPER AIR SOUNDING AT ALBANY. THE H850 TEMP WAS -30.8 C. THE PREVIOUS RECORD COLD 850 MB TEMPERATURE WAS -30.5 C SET BACK ON 4 JANUARY 1981 AND ON 18 JANUARY 1982. PUTTING THE RECORDS ASIDE...MAIN STORY THIS MORNING IS THE DANGEROUS WIND CHILLS OF 25 TO 40 BELOW ZERO. FROSTBITE CAN OCCUR ON EXPOSED FLESH IN JUST 10 MINUTES. MUCH OF THE REGION WILL SEE LOWS BETWEEN 10 AND 15 BELOW ZERO EARLY THIS MORNING WITH A FEW LOCATIONS NEAR - 20 ACROSS THE HIGHER TERRAIN. OCEAN EFFECT SNOW SHOWERS FOR OUTER-CAPE... WHILE THE REST OF THE REGION WAS CLEAR AND BITTERLY COLD...OCEAN EFFECT SNOW SHOWERS HAVE DEVELOPED ACROSS THE OUTER-CAPE. DESPITE LIMITED FETCH WITH WINDS AT 300 TO 310 DEGREES...MID LEVEL TROUGH SINKING SOUTH IS LIKELY AIDING IN SEEDER FEEDER PROCESSES. ALSO...EXTREME INSTABILITY WITH NEARLY 1500 J/KG OF OCEAN INDUCED CAPE IS LIKELY OVERCOMING THE VERY LIMITED FETCH. SO FAR THE BULK OF THE SNOW HAS BEEN NORTH OF ORLEANS AND ESPECIALLY IN THE PROVINCETOWN AREA....BUT THE SNOW HAS RECENTLY SLIPPED SOUTH INTO CHATHAM. GIVEN LIMITED FETCH NOT EXPECTING MUCH MORE THAN FLURRIES FROM HYANNIS TO THE UPPER CAPE. SNOW AMOUNTS ACROSS THE OUTER-CAPE WILL VARY CONSIDERABLY OVER SHORT DISTANCES AND WILL BE TOUGH TO MEASURE WITH THE STRONG WINDS. OVERALL...A SWATH OF 1 TO 3 INCHES OF SNOW IS POSSIBLE THIS MORNING. SHOULD SEE THE SNOW TAPER OFF THIS AFTERNOON...BUT LOW CLOUDS WILL LINGER ACROSS THE OUTER-CAPE. THE BIGGEST CONCERN WILL PROBABLY BE THE STRONG WINDS/BITTERLY COLD TEMPS WHICH WILL RESULT IN LOCALIZED POOR VISIBILITY AT TIMES. A SPECIAL WEATHER STATEMENT IS IN EFFECT. THIS AFTERNOON... WHILE IT STILL WILL BE BREEZY AND BITTERLY COLD...TEMPERATURES WILL RECOVER ENOUGH TO ALLOW WIND CHILL HEADLINES TO EXPIRE THIS AFTERNOON. 850 MB TEMPERATURES ONLY MODERATE TO -22C...SO HIGH TEMPS WILL ONLY REACH INTO THE HIGH SINGLE DIGITS TO AROUND 10 ABOVE IN MOST LOCATIONS. NEW RECORD LOW HIGH TEMPS WILL LIKELY BE SET IN SOME LOCATIONS.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... ***BITTERLY COLD TONIGHT BUT WITHOUT THE WIND*** HIGH PRESSURE BUILDING ACROSS SOUTHERN NEW ENGLAND WILL RESULT IN LIGHT WINDS AND AN IDEAL NIGHT OF RADIATIONAL COOLING. GIVEN THE ARCTIC AIR FIRMLY IN PLACE ACROSS THE REGION...IT WILL BE ANOTHER BITTERLY COLD NIGHT BUT WITH OUT THE WIND. GUIDANCE TEMPS MAY BE 10+ DEGREES TOO WARM IN THE TYPICALLY PRONE OUTLYING LOCATIONS. WOULD THINK WE SEE LOW TEMPS NEAR 20 BELOW ZERO IN THE TYPICALLY COLDEST OUTLYING LOCATIONS OF WESTERN MA. MOST OTHER AREAS WILL LIKELY SEE LOW TEMPS BETWEEN -5 AND -15...BUT SOME URBAN HEAT ISLANDS WILL NOT GET QUITE THAT COLD. ONE EXAMPLE IS BOSTON...WHICH SHOULD SEE LOW TEMPS REMAIN ABOVE ZERO GIVEN LACK OF COLD ADVECTION WITH THAT LOCATION NEEDS TO GET BELOW ZERO. && .LONG TERM /MONDAY THROUGH SATURDAY/... HIGHLIGHTS... * WINTRY MIX POSSIBLE MON NIGHT * HEAVY RAIN EXPECTED ON TUE * BRIEF COOL DOWN WED NIGHT INTO THU OVERVIEW AND MODEL PREFERENCES... ALTHOUGH CURRENT WESTERN HEMISPHERIC SETUP SHOWS NEGATIVE NAO/AO AND POSITIVE PNA...WHICH HAS ALLOWED ARCTIC AIR TO SPILL SOMEWHAT MODIFIED ARCTIC AIR ACROSS THE REGION...THIS WILL BE CHANGING. IN FACT...THE MORE AMPLIFIED FLOW PATTERN BECOMES MUCH MORE ZONAL ACROSS THE CENTRAL CONUS MUCH OF THE COMING WEEK AND THESE SAME TELECONNECTIONS TREND IN THE OPPOSITE DIRECTION. THIS SUGGESTS A FAIRLY ACTIVE PATTERN BUT WITH LESS COLD AIR THAN THE LAST WEEK OR SO. INDEED THE TWO MOST IMPACTFUL FEATURES CURRENTLY PROGGED LOOK TO BE INSIDE RUNNERS THANKS TO EARLIER SHARPENING OF THE ASSOCIATED TROF ALONG WITH SOME INFLUENCE OF THE SRN STREAM. A BLEND OF OPERATIONAL GUIDANCE WILL BE USED AS A BASELINE AS THE TRACK DISCREPANCIES ARE BEGINNING TO CONVERGE FOR THE TUE LOW PRES PASSAGE. DETAILS... MON... HIGH PRES WILL BE MOVING OVER THE REGION THROUGH THE DAY ON MON. ALTHOUGH TEMPS WILL START COLD THANKS TO GOOD RADIATIONAL COOLING SUN NIGHT...MODEST LATE DAY RETURN FLOW WILL ALLOW FOR SOME WARMING AS H92 TEMPS INCREASE BACK TO NEAR -8C. THIS WILL ALLOW A BIT OF A REPRIEVE AS HIGHS GO BACK INTO THE 20S TO MID 30S. HOWEVER...DIURNAL COOLING...ALONG WITH EVAPORATIONAL COOLING IS EXPECTED AS ISENTROPIC LIFT BEGINS BY LATE AFTERNOON/EVENING. MON NIGHT INTO TUE NIGHT... STRENGTHENING BUT NON-OCCLUDING LOW PRES APPROACHES FROM THE MISSISSIPPI VALLEY...CARRYING WITH IT GULF MOISTURE AND PWATS OF 2 STD DEVIATIONS ABOVE NORMAL...OR GENERALLY ABOVE 1.00 INCHES. ISENTROPIC LIFT ON THE FRONT END MON NIGHT WILL YIELD EVAPORATIVE COOLING AND DIURNAL COOLING SUCH THAT PRECIP WILL START IN THE EVENING AS LIGHT-MOD SN. QPF VALUES DURING THIS PERIOD RANGE FROM ABOUT 0.1 TO 0.25 INCHES...SO WHERE IT STAYS DEEPLY COLDEST THE LONGEST /NW MA/...AS MUCH AS 2-3 INCHES OF SNOW /LESS AND LESS TOWARD THE COAST/ IS POSSIBLE BEFORE WARMER AIR ABOVE 0F MOVES IN AT H92-H85. THIS WILL BEGIN A TRANSITION TO RAIN FROM S-N AFTER MIDNIGHT THROUGH ABOUT 7AM. NOT A TRADITIONAL COLD AIR DAMMING SITUATION HERE AS HIGH PRES IS ORIENTED WELL TO THE ENE...ALTHOUGH DO NOTE SOME RESPONSE IN THE MASS FIELDS IN THE FORM OF AN INVERTED RIDGE. THEREFORE...CAN/T RULE OUT SOME ICE ACCRETION ON THE NEW FRESH SNOWPACK...ESPECIALLY IN THE CT VALLEY AND COLDER VALLEYS OF THE WORCESTER HILLS AND NRN CT HIGH TERRAIN. POSSIBLE T-0.2 INCHES OF ICE IS POSSIBLE...SUGGESTING AT LEAST WINTER WX ADVISORIES ARE LIKELY GOING TO BE NEEDED. BY TUE...WARM ADVECTION WILL HAVE INCREASED ENOUGH TO BRING SFC TEMPS ABOVE NORMAL IN SPITE OF THE MODEST SNOWPACK ACROSS THE REGION. THIS WILL LEAD TO A CHANGEOVER TO ALL RAIN. HEAVY RAIN LOOKS LIKELY AT TIMES GIVEN THE HIGH PWATS AND INCREASING LLJ WITH 60-70 KT POSSIBLE AS LOW AS H92. QPF VALUES COULD BE GREATER THAN AN INCH AFTER THE CHANGEOVER GIVEN THE DYNAMICS AND MOISTURE AVAILABLE...SO WILL NEED TO WATCH FOR MINOR/NUISANCE FLOODING ESPECIALLY AS SNOWS COULD CLOG AREA DRAINS. OTHER ISSUES IS THE LLJ ITSELF...WHICH COULD YIELD DANGEROUS STRONG WINDS. HOWEVER...THE EARLY SNOW AND INCREASE IN TEMPS ALOFT COULD YIELD ENOUGH OF AN INVERSION TO LIMIT POTENTIAL WIND GUSTS. BUFKIT CURRENTLY SUPPORTS THIS HYPOTHESIS...KEEPING ANY MOMENTUM TRANSFER NUMBERS BELOW EVEN ADVISORY CRITERIA. WILL STILL NEED TO WATCH THIS HOWEVER...GIVEN HOW STRONG THE LLJ IS EXPECTED TO BE /AS MUCH AS 3 STD DEVIATIONS ABOVE H92 NORMAL/. OVERNIGHT LOWS IN THE 20S WILL GIVE WAY TO HIGHS MAINLY IN THE UPPER 30S AND 40S...ALTHOUGH AN ISOLATED 50F CANNOT BE RULED OUT. WED INTO THU... SECONDARY ARCTIC FRONT WILL BE SLIDING THROUGH THE REGION FOLLOWING THE EXITING LOW PRES. WED HIGHS STILL MILD...MAINLY IN THE UPPER 30S TO UPPER 40S AS THE COLD AIR WILL NOT ARRIVE UNTIL OVERNIGHT. AN ISOLATED OVERNIGHT SHSN IS POSSIBLE AS THE WAVE MOVES THROUGH...BUT OVERALL THIS FEATURE IS MOISTURE STARVED SO ANY ACCUMS WOULD BE LIGHT. HOWEVER THE INCREASED CLOUD COVER WILL KEEP MINS MAINLY IN THE 20S. BY THU...H92 TEMPS ARE BACK TO NEAR -10C...SO HIGHS WILL ONLY BE IN THE 20S TO MID 30S AT THE WARMEST IN SPITE OF THE CLEARING SKIES. THU NIGHT INTO FRI... HIGH PRES CRESTS OVER THE REGION...WITH ANOTHER GRADUAL WARMING TREND AS THE HIGH MOVES E AND H92 TEMPS RETURN TO NEAR -4C. THIS SUGGESTS HIGHS FRI BACK IN THE 40S ONCE AGAIN. SAT INTO SUN... ALTHOUGH FAR FROM A WASHOUT...ALBERTA CLIPPER ASSOCIATED WITH SHORTWAVE ENERGY CURRENTLY WRAPPED UP IN THE ALLEUTIAN VORTEX WILL BE CROSSING THE REGION. CURRENT STEERING FLOW SUGGESTS A NORTHWARD PASSAGE WHICH KEEPS SRN NEW ENGLAND ON THE CLIMATOLOGICALLY DRIER SIDE OF A CLIPPER. THEREFORE...EXPECT THE MILDER WX TO CONTINUE...WITH A RISK FOR SHRA FOR A PERIOD ONCE THE TIMING IS BETTER LOCKED IN. THIS WILL BE LIKELY ONCE THE AFOREMENTIONED SHORTWAVE MOVES ONSHORE FROM THE PACIFIC. && .AVIATION /10Z SUNDAY THROUGH THURSDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/... TODAY AND TONIGHT...HIGH CONFIDENCE. VFR CONDITIONS WITH CLEAR SKIES. NORTHWEST WIND GUSTS OF 20 TO 30 KNOTS GRADUALLY DIMINISH TODAY AND ESPECIALLY BY EARLY THIS EVENING. THE EXCEPTION TO THE CLEAR SKIES WILL BE THE OUTER-CAPE/NANTUCKET WHERE OCEAN EFFECT CLOUDS BETWEEN 2000 TO 3000 FEET WILL PERSIST INTO THE AFTERNOON. OCEAN EFFECT SNOW SHOWERS WILL ALSO CONTINUE ACROSS THE OUTER-CAPE THIS MORNING...BEFORE TAPERING OFF THIS AFTERNOON. THE LIMITED FETCH WILL RESULT IN LITTLE MORE THAN FLURRIES FROM HYANNIS TO THE UPPER CAPE. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK /MONDAY THROUGH THURSDAY/... MON...HIGH CONFIDENCE. MAINLY VFR THROUGH THE DAY WITH HIGH PRES. WINDS SHIFT TO THE SE. MON NIGHT INTO TUE NIGHT...MODERATE CONFIDENCE. PERIODS OF IFR/MVFR DUE TO A COMBINATION OF LOW CIGS AND VSBYS. PRECIP STARTS AS SNOW MON EVENING...THEN TRANSITIONS TO A BRIEF PERIOD OF FZRA/SLEET BRIEFLY BEFORE TURNING TO ALL RAIN DURING THE DAY ON TUE. SE WINDS MAY GUST 20-30 KT AT TIMES DURING THE DAY ON TUE...BUT VERY STRONG WINDS JUST OFF THE DECK COULD MIX DOWN AT TIMES. EXPECT LLWS...WITH AS MUCH AS 60-70 KT AT 2KFT. WED INTO THU...MODERATE CONFIDENCE. MAINLY VFR BUT WITH COOLING CONDITIONS LATE WED INTO THU. LOW RISK FOR AN ISOLATED SHSN WED NIGHT. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/...HIGH CONFIDENCE. ***HEAVY FREEZING SPRAY/ARCTIC SEA SMOKE AND GALE FORCE WIND GUSTS PERSISTS INTO MID/LATE MORNING BEFORE DIMINISHING*** TODAY...INCREDIBLE ARCTIC OUTBREAK FOR THE MODERN ERA WILL RESULT IN AREAS OF HEAVY FREEZING SPRAY AND GALE FORCE WIND GUSTS THIS MORNING. IN ADDITION...ARCTIC SEA SMOKE WILL OCCUR WITH LARGE AIR TO SST DIFFERENTIAL. WINDS SHOULD GRADUALLY BEGIN TO SLACKEN LATER THIS MORNING AND EARLY AFTERNOON...DROPPING TO SMALL CRAFT LEVELS. STILL MAY HAVE POCKETS OF MODERATE FREEZING SPRAY PERSIST INTO THE AFTERNOON ACROSS OUR EASTERN MA WATERS. TONIGHT....LINGERING SMALL CRAFT SEAS/WIND GUSTS AND MODERATE FREEZING SPRAY ACROSS OUR EASTERN WATERS SHOULD DIMINISH BELOW CRITERIA AFTER MIDNIGHT. OTHERWISE...WINDS/SEAS BELOW SCA THRESHOLDS THE REST OF THE NIGHT AS LARGE HIGH PRESSURE BUILDS ACROSS THE REGION. SUNDAY INTO SUNDAY NIGHT...HIGH CONFIDENCE. NW-WINDS TAPERING ALONG WITH SEAS. GALES CONCLUDING...SMALL CRAFT HEADLINES WILL LIKELY HOLD FOR A MAJORITY OF THE FORECAST PERIOD. HIGH PRESSURE BUILDING ACROSS THE WATERS. OUTLOOK /MONDAY THROUGH THURSDAY/... MON...HIGH CONFIDENCE. QUIET BOATING WEATHER WITH HIGH PRES OVER THE WATERS. MON NIGHT INTO TUE NIGHT...MODERATE CONFIDENCE. LOW PRES WILL APPROACH FROM THE SW...THEN MOVE INLAND DURING THE DAY TUE. INCREASE SE WINDS WILL LEAD TO GUSTS 25-30 KT MON NIGHT...THEN SHIFTING LATE TUE NIGHT. SEAS BUILD DURING THIS TIME AS WELL...AND COULD REACH 10-13 FT BY TUE EVENING. SMALL CRAFT ADVISORIES WILL BE NEEDED. THERE IS A LOW RISK FOR GALES...BUT IT IS UNCERTAIN AT THIS TIME. WED AND WED NIGHT...HIGH CONFIDENCE. WINDS SHIFT TO THE W...BUT DROP BELOW 25 KT. SEAS WILL BEGIN TO SUBSIDE...BUT WILL TAKE SOME TIME. SO SMALL CRAFT ADVISORIES ARE LIKELY TO CONTINUE THROUGH MUCH OF THE DAY FOR SEAS ALONE. THU...HIGH CONFIDENCE. ALTHOUGH WIND GUSTS SHOULD REMAIN BELOW THRESHOLD AS WINDS SHIFT TO THE NW AND PERSIST...THERE COULD BE 5-7 FT SEAS PERSISTING ON THE OCEAN WATERS. && .CLIMATE...
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***COLDEST TEMPERATURES RECORDED IN BOSTON/WORCESTER SINCE 1957*** BOSTON SET A NEW RECORD LOW OF -4 JUST BEFORE MIDNIGHT ON FEBRUARY 13TH. THROUGH 4 AM THIS MORNING...TEMP IS DOWN TO -9 WHICH ALSO ESTABLISHES A NEW RECORD FOR TODAY. THIS IS THE FIRST TIME BOSTON HAS SET A RECORD LOW IN THE MONTH OF FEBRUARY SINCE 1967. ITS ALSO THE COLDEST TEMPERATURE AT BOSTON SINCE 1957! THROUGH 4 AM THIS MORNING...WORCESTER HAS DROPPED TO -15 BREAKING THEIR OLD RECORD LOW OF -11 SET IN 1979. ITS ALSO THE COLDEST TEMPERATURES IN WORCESTER SINCE 1957! THROUGH 4 AM THIS MORNING...HARTFORD HAS DROPPED TO -10 WHICH BREAKS THEIR OLD RECORD LOW -9 IN 1979. THROUGH 4 AM THIS MORNING...PROVIDENCE HAS DROPPED TO -8 WHICH BREAKS THEIR OLD RECORD OF LOW OF -7 IN 1979. RECORD COLD HIGHS FOR FEB 13TH - 14TH... BOSTON.......15/1979 - 14/1916 HARTFORD.....11/1979 - 11/1979 PROVIDENCE...10/1979 - 10/1979 WORCESTER.... 8/1899 - 7/1979 BLUE HILL.... 9/1899 - 10/1979 RECORD COLD LOWS FOR FEB 13TH - 14TH - 15TH... BOSTON...... -3/1967 - -3/1934 - -14/1943 HARTFORD.... -7/1967 - -9/1979 - -18/1943 PROVIDENCE.. -5/1967 - -7/1979 - -14/1943 WORCESTER...-12/1967 - -11/1979 - -19/1943 BLUE HILL...-10/1967 - -9/1979 - -18/1943
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&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...WIND CHILL WARNING UNTIL NOON EST TODAY FOR CTZ002>004. MA...WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR MAZ022>024. WIND CHILL WARNING UNTIL NOON EST TODAY FOR MAZ002>021-026. RI...WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR RIZ008. WIND CHILL WARNING UNTIL NOON EST TODAY FOR RIZ001>007. MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 11 AM EST THIS MORNING FOR ANZ231>235-237-250-251-254>256. GALE WARNING UNTIL 10 AM EST THIS MORNING FOR ANZ231>235-237- 251-255-256. SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ230- 236. GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR ANZ250-254. && $$ SYNOPSIS...FRANK/DOODY NEAR TERM...FRANK SHORT TERM...FRANK LONG TERM...DOODY AVIATION...FRANK/DOODY MARINE...FRANK/DOODY CLIMATE...FRANK

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