Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 111200 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 700 AM EST THU FEB 11 2016 .SYNOPSIS... A STRONG COLD FRONT TODAY WILL BRING SCATTERED SNOW SHOWERS WITH A FEW LOCALIZED HEAVIER SNOW SQUALLS. BITTERLY COLD WEATHER IS EXPECTED THIS WEEKEND. THERE IS POTENTIAL FOR MORE PRECIP EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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***SCATTERED SNOW SHOWERS WITH A FEW LOCALLY HEAVIER SNOW SQUALLS EXPECTED TODAY*** 7 AM UPDATE... MODEST VORT ADVECTION THIS MORNING IS LEADING ANOTHER ROUND OF SHALLOW AND LIGHT SN ACROSS CT AND THE LOWER CT VALLEY OF MA. MODELS HAVING DIFFICULTY RESOLVING THIS FEATURE SO POPS ARE MAINLY MANUALLY GENERATED THIS MORNING...BUT BLENDED INTO THE NAM THIS AFTERNOON. THE REASON FOR THIS BLEND IS IT APPEARS TO BE CAPTURING THE INSTABILITY INCREASE EXPECTED THIS AFTERNOON AND HIGHLIGHTS THE SNOW SQUALL RISK NICELY. OTHERWISE...MOST OF THE FORECAST PARAMETERS ARE ON TRACK THIS MORNING. PREVIOUS DISCUSSION... ANOTHER FAIRLY ROBUST SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT APPROACHES THE REGION FROM THE WEST EARLY THIS MORNING. THIS WILL ALLOW SCATTERED SNOW SHOWERS TO OVERSPREAD SOUTHERN NEW ENGLAND THROUGH MID MORNING. THERE ARE ALSO SEVERAL PARAMETERS INDICATING THE POTENTIAL FOR LOCALIZED HEAVIER SNOW SQUALLS. THESE INCLUDE 0 TO 3 KM LAPSE RATES INCREASING TO NEAR 9C/KM...SHORTWAVE ENERGY AND LOW LEVEL CONVERGENCE ON AN ARCTIC COLD FRONT. BIGGEST UNCERTAINTY IS AREAL COVERAGE OF THE ACTIVITY WHICH WILL HINGE ON THE AMOUNT OF LOW LEVEL MOISTURE. THE GFS SEEMS TO HAVE HIGHER RELATIVE HUMIDITY VALUES IN THE LOWEST 0-2KM OF THE ATMOSPHERE THAN THE NAM...PROBABLY WHY IT SHOWS MORE QPF. WITH ALL THAT SAID...EXPECT SCATTERED SNOW SHOWERS ALONG WITH THE RISK OF A FEW LOCALIZED HEAVIER SQUALLS. MAIN CONCERN IS THAT ANY LOCALIZED SQUALLS MAY RESULT IN ROADS QUICKLY BE COME SNOW COVERED/SLIPPERY ALONG WITH BRIEF POOR VISIBILITY. UNLIKE YESTERDAY AFTERNOON...TEMPS WILL REMAIN BELOW FREEZING. HIGHS WILL PRETTY MUCH HOLD IN THE 20S IN MOST LOCATIONS TODAY...SO ANY SNOW SHOWER OF MODERATE INTENSITY WILL QUICKLY STICK TO ROADWAYS EVEN DURING THE AFTERNOON. SNOW ACCUMULATIONS WILL GENERALLY BE A COATING TO LESS THAN 1 INCH FOR MOST LOCATIONS...BUT CAN NOT RULE OUT LOCALIZED 1 TO 2 INCH AMOUNTS. IT WILL BECOME QUITE BLUSTERY DURING THE AFTERNOON WITH NORTHWEST WIND GUSTS OF 25 TO 35 MPH WITH WIND CHILLS IN THE HIGH SINGLE DIGITS AND TEENS.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... ***WIND CHILLS DROPPING TO BETWEEN 0 AND 10 BELOW ZERO LATE TONIGHT INTO EARLY FRIDAY MORNING*** TONIGHT... ANY LEFT OVER ISOLATED SNOW SHOWERS SHOULD COME TO AN END THIS EVENING AND SKIES WILL BECOME MOSTLY CLEAR. A SHOT OF VERY COLD AIR WILL BE USHERED IN ON GUSTY NORTHWEST WINDS WITH 850T FALLING TO NEAR -20C. LOW TEMPS WILL GENERALLY BOTTOM OUT IN THE SINGLE DIGITS TO AROUND 10 ABOVE BY DAYBREAK FRIDAY. WIND CHILL VALUES WILL DROP TO BETWEEN 0 AND 10 BELOW ZERO. FRIDAY... MOSTLY SUNNY SKIES DURING THE MORNING WILL GIVE WAY TO A GRADUAL INCREASE IN CLOUDS FROM WEST TO EAST DURING THE AFTERNOON. THIS OUT AHEAD OF AN APPROACHING ARCTIC COLD FRONT. HIGH TEMPS WILL ONLY REACH INTO THE LOWER TO MIDDLE 20S BUT WINDS WILL BE MUCH LIGHTER THAN THIS AFTERNOON. DRY WEATHER SHOULD PREVAIL FOR MUCH OF THE DAY...BUT MAY SEE A FEW FLURRIES/LIGHT SNOW SHOWERS DEVELOP ACROSS OUR WESTERN ZONES BY EARLY EVENING WITH SOME MID LEVEL WARM ADVECTION. OF MORE INTEREST...WILL LIKELY SEE SOME RARE OCEAN EFFECT SNOW SHOWERS DEVELOP ALONG THE SOUTH COAST/CAPE AND ISLANDS BY LATE AFTERNOON/EARLY EVENING. SOUTHWEST FLOW DEVELOPS AHEAD OF THE ARCTIC COLD FRONT...BUT WITH 850T STILL AROUND -14C. THIS YIELDS 850/SST DIFFERENTIAL OF AROUND 22C AND GENERATES BETWEEN 400 AND 500 J/KG OF OCEAN INDUCED CAPE. MOST OUR MESO MODELS ARE GENERATING SCATTERED SNOW SHOWERS NEAR THE SOUTH COAST BY 00Z SATURDAY...ESPECIALLY ACROSS THE CAPE/ISLANDS. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... HIGHLIGHTS... * SNOW SHOWERS POSSIBLE THROUGH SAT * MUCH COLDER AIR MOVES INTO SOUTHERN NEW ENGLAND FOR THE WEEKEND * MORE PRECIPITATION POSSIBLE EARLY NEXT WEEK OVERVIEW AND MODEL PREFERENCES... HIGHLY AMPLIFIED FLOW PATTERN WILL GRADUALLY NEUTRALIZE TOWARD NEXT WEEK AS WEEKEND SRN AND NRN STREAM PHASING ALLOWS FOR SOME FLATTENING OF THE FLOW ACROSS THE NE CONUS. UNTIL THEN HOWEVER...CONDUIT FOR COLD AIR...WITH VERY CYCLONICALLY CURVED FLOW WILL YIELD A COLD AND UNSETTLED PATTERN CULMINATING IN POTENTIAL STORM FOR MID NEXT WEEK...BUT THIS FEATURE REMAINS ELUSIVE GIVEN SEVERE TRACK DISCREPANCIES AMONG OPERATIONAL AND ENSEMBLE SOLUTIONS. THERE IS ENOUGH SYNOPTIC AGREEMENT THAT A BLEND OF OPERATIONAL GUIDANCE WILL BE USED FOR THE BASELINE THROUGH THE MID TERM. HOWEVER...WILL FOLLOW PREVIOUS FORECASTER/S THINKING AND LEAN MORE HEAVILY ON ENSEMBLES FOR THE MIDDLE OF NEXT WEEK GIVEN THE TRACK UNCERTAINTY. DETAILS... FRI NIGHT INTO SAT... VERY ROBUST ARCTIC COLD FRONT WILL BE MOVING THROUGH THE AREA...FRI NIGHT AS ENERGY TRANSFERS FROM LOW PRES MOVING OUT OF ONTARIO TO LOW PRES DEVELOPING S OF THE GULF OF MAINE INTERSECTION WITH NOVA SCOTIA. WHILE THIS IS TOO FAR OFFSHORE FOR DIRECT IMPACT ON SRN NEW ENGLAND A STRONG INVERTED TROF IS EXPECTED TO DEVELOP WHICH WILL NEED TO BE WATCHED AS IT IS LIKELY TO PRODUCE ADVISORY TO WARNING LEVEL SNOWFALL OVER A VERY LOCALIZED AREA. CURRENT ORIENTATION IS MAINLY ACROSS COASTAL MAINE. A FEW SHSN ARE POSSIBLE ACROSS THE REGION AS THE COLD FRONT PASSES...AND WILL NEED TO MONITOR CAPE COD/ANN FOR OCEAN EFFECT GIVEN 25C OR GREATER SST-H85 DELTA-T VALUES. WINDS HAVE MAINLY A WESTERLY COMPONENT...SO THIS WILL NOT BE AS WIDESPREAD AS THEY COULD BE SHOULD THE WIND ORIENT MORE TO THE N. OTHERWISE...H92 TEMPS DROP FROM -12C TO -24C BY LATE SAT SUGGESTS THAT TEMPS MAY HOLD OR EVEN DROP DURING THE DAY ON SAT. EXPECT LOWS IN THE TEENS AND HIGHS ONLY IN THE 20S. SAT NIGHT INTO SUN... VERY COLD TEMPERATURES WILL ATTEMPT TO MELT THE WARM HEARTS OF VALENTINES DAY. ENSEMBLES SHOW NEARLY 80 PERCENT PROBS OF H85 TEMPS BELOW -30C. THIS WILL BE ACCOMPANIED BY A SECONDARY SHORTWAVE PASSAGE WHICH WILL ENHANCE NW WINDS ACROSS THE REGION DURING THE OVERNIGHT AND MORNING HOURS. AMBIENT TEMPERATURES ALONE WILL BE IN THE SINGLE DIGITS BELOW 0F...BUT COMBINED WITH THIS 20-30 MPH BREEZE...SUSPECT 15-25 BELOW ZERO WIND CHILLS ACROSS MUCH OF THE REGION. WILL LIKELY NEED WIND CHILL WARNINGS/ADVISORIES FOR SAT NIGHT INTO SUN. STILL COLD ON SUN AS HIGHS WILL STRUGGLE TO MAKE IT INTO THE SINGLE DIGITS LEAVING WIND CHILLS BELOW 0F. THE SECONDARY ARCTIC ENHANCEMENT WILL ALSO LEAD TO AN INCREASED RISK FOR OCEAN EFFECT SNOWS ALONG CAPE ANN/COD AGAIN AND WILL SHIFT THE INVERTED TROF TO THE S. WILL NEED TO MONITOR THIS SNOWFALL. SUN NIGHT INTO MON... HIGH PRES CRESTS OVER THE REGION WITH SLIGHT WARMING TREND. H92 TEMPS REBOUND TO NEAR -12C. SO HIGHS WILL RISE CLOSER TO SEASONAL NORMALS...MAINLY IN THE 20S AND LOW 30S. LESS OF A RISK FOR COLD WIND CHILLS AS PRES GRADIENT SLACKENS. TUE AND WED... INTERESTING SETUP WITH SRN STREAM REGAINING CONTROL AND DEVELOPING A LOW PRES WITH CONNECTION TO GULF OF MEXICO MOISTURE. LOTS OF UNCERTAINTY IN THE TRACK AS GEFS MEAN IS OVER THE BENCHMARK WHILE ECENS MEAN IS WELL INLAND. IN ANY CASE...A POTENTIAL P-TYPE ISSUE STORM WITH A FAIR AMOUNT OF POTENTIAL QPF. THE WEDGE OF COLD AIR LEFT OVER MAY LEAD TO SOME ICE DEVELOPMENT DEPENDING ON THIS TRACK...OR EVEN JUST ALL RAIN/SNOW. WILL NEED TO CONTINUE TO MONITOR THIS FEATURE AS IMPACTS COULD BE SUBSTANTIAL IF ICE IS INVOLVED. FOR NOW...THE BLEND DOES HAVE A BIT OF ICE TRANSITIONING TO MAINLY RAIN ACROSS SRN NEW ENGLAND...BUT THIS IS LIKELY TO CHANGE. && .AVIATION /11Z THURSDAY THROUGH MONDAY/...
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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/... TODAY...HIGH CONFIDENCE OVERALL...LOWER CONFIDENCE IN EXACT TIMING OF ANY SHSN THROUGH THE DAY. OUTSIDE OF SOME LIGHT SN IN THE CT VALLEY...MAINLY VFR CONDITIONS ARE EXPECTED THROUGH ABOUT MID MORNING. THEN FROM MID MORNING THROUGH MID-LATE AFTERNOON...THERE WILL BE AN ONGOING RISK FOR SHSN...SOME OF WHICH COULD BE BRIEFLY HEAVY WITH GUSTY WINDS AND LIGHT ACCUMULATIONS ON RUNWAYS. THIS RISK DIMINISHES THIS EVENING. OTHERWISE...WIND GUSTS INCREASE THIS AFTERNOON OUT OF THE W...WITH 20-30KT POSSIBLE. TONIGHT...HIGH CONFIDENCE. ANY LEFT OVER ISOLATED SNOW SHOWERS COME TO AN END THIS EVENING. OTHERWISE...VFR CONDITIONS. FRIDAY...HIGH CONFIDENCE. MAINLY VFR BUT SOME MARGINAL MVFR CIGS MAY DEVELOP FRIDAY AFTERNOON. IN ADDITION...OCEAN EFFECT SNOW SHOWERS MAY DEVELOP ACROSS THE SOUTH COAST AND ESPECIALLY CAPE/ISLANDS BETWEEN 21Z AND 00Z RESULTING LOCALIZED IFR CONDITIONS. KBOS TERMINAL...MODERATE TO HIGH CONFIDENCE IN TAF. SCATTERED SNOW SHOWERS WILL BE IN THE VICINITY OF THE TERMINAL LATER THIS MORNING INTO EARLY THIS EVENING. TEMPS WILL REMAIN BELOW FREEZING...SO ANY SNOW SHOWER THAT MOVES OVER THE TERMINAL MAY COAT THE AIRPORT RUNWAYS. KBDL TERMINAL...MODERATE TO HIGH CONFIDENCE IN TAF. SCATTERED SNOW SHOWERS WILL BE IN THE VICINITY OF THE TERMINAL LATER THIS MORNING INTO EARLY THIS EVENING. TEMPS WILL REMAIN BELOW FREEZING...SO ANY SNOW SHOWER THAT MOVES OVER THE TERMINAL MAY COAT THE AIRPORT RUNWAYS. OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/... FRI NIGHT...HIGH CONFIDENCE. GUSTY NW WINDS...BUT MAINLY VFR. SATURDAY AND SUNDAY...MODERATE CONFIDENCE. MAINLY VFR CONDITIONS. NW WINDS GUSTING TO 25-30 KTS LIKELY. BITTERLY COLD TEMPERATURES EXPECTED. THERE IS A LOW RISK FOR COASTAL SNOW SHOWERS PARTICULARLY CAPE COD...CAPE ANN AND PORTIONS OF THE SOUTH SHORE. MONDAY...LOW CONFIDENCE. VFR TO START BUT LATE DAY DROPPING TO MVFR/IFR POSSIBLE WITH ONSET OF PRECIPITATION. TIMING UNCERTAIN.
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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 AND TONIGHT...HIGH CONFIDENCE. WEST TO NORTHWEST WIND GUSTS WILL INCREASE TO AROUND 35 KNOTS THIS AFTERNOON AND CONTINUE INTO TONIGHT OVER THE OPEN WATERS. THIS A RESULT OF VERY COLD AIR WITH 850T DROPPING TO NEAR -20C PROMOTING EXCELLENT MIXING OVER THE RELATIVELY MILD OCEAN. GALE WARNINGS ALL WATERS EXCEPT STRONG SCA HEADLINES BOSTON HARBOR/NARRAGANSETT BAY. FINALLY...ADVISORY FOR MODERATE FREEZING SPRAY FOR EASTERN MA WATERS/CAPE COD BAY TONIGHT. FRIDAY...HIGH CONFIDENCE. WESTERLY WIND GUSTS WILL DIMINISH BY EARLY FRIDAY MORNING BUT REMAIN AT SMALL CRAFT ADVISORY THRESHOLDS THROUGH MUCH OF THE MORNING. WINDS/SEAS SHOULD FINALLY DROP BELOW SCA LEVELS DURING THE AFTERNOON AS WINDS SHIFT TO THE SOUTHWEST AHEAD OF AN ARCTIC COLD FRONT. OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/... FRIDAY NIGHT...HIGH CONFIDENCE. WEAK HIGH PRES WILL LEAD TO A PERIOD OF QUIET BOATING WEATHER OVERNIGHT. SAT INTO SUN...MODERATE CONFIDENCE. STRONG N-NW WINDS WILL LEAD TO GALE FORCE WIND GUSTS AT TIMES ALONG WITH MODERATE FREEZING SPRAY. SNOW SHOWERS ARE LIKELY OFFSHORE. THESE WINDS DISSIPATE SOME ON SUN...BUT ITS LIKELY SMALL CRAFT ADVISORIES WILL FOLLOW. MONDAY...MODERATE CONFIDENCE. WINDS REMAIN BELOW SMALL CRAFT CRITERIA... BUT SEAS BUILD AS SOME SORT OF LOW PRESSURE SYSTEM APPROACHES SOUTHERN NEW ENGLAND.
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&& .CLIMATE... BITTERLY COLD TEMPERATURES ARE EXPECTED THIS WEEKEND. RECORD COLD HIGH AND LOW TEMPERATURES MAY BE TIED OR BROKEN. HERE ARE THE CURRENT RECORDS FOR THE WEEKEND. 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 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 4 AM EST FRIDAY FOR ANZ231>235-237-250-251-254>256. SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 4 AM EST FRIDAY FOR ANZ230-236. FREEZING SPRAY ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST FRIDAY FOR ANZ231-250-251. && $$ SYNOPSIS...FRANK/DOODY NEAR TERM...FRANK/DOODY SHORT TERM...FRANK LONG TERM...DOODY AVIATION...FRANK/DOODY MARINE...FRANK/DOODY CLIMATE...

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