Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 261509 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1009 AM EST THU FEB 26 2015 .SYNOPSIS... LOW PRESSURE PASSING OUT TO SEA MAY BRING AN INCH OR TWO OF SNOW TODAY TO THE FAR SOUTHEAST NEW ENGLAND COAST. DRY BUT UNSEASONABLY COLD WEATHER CONTINUES TONIGHT AND FRIDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. TEMPS SLOWLY MODERATE SAT AS HIGH PRES BUILDS INTO THE REGION...THEN A FRONTAL SYSTEM MAY BRING SOME SNOW LATE SUN INTO MON AND POSSIBLY FOLLOWED BY ADDITIONAL SNOW OR MIXED SNOW AND RAIN TUE NIGHT INTO WED. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... *** AN INCH OR TWO OF SNOW POSSIBLE TODAY FOR THE FAR SOUTHEAST NEW ENGLAND COAST *** 10 AM UPDATE... WIDESPREAD LIGHT RETURNS NOTED ON RADAR...BUT STILL MOSTLY ALOFT DUE TO PRESENCE OF VERY DRY LAYER IN THE LOW LEVELS AS INDICATED BY CHH/OKX SOUNDINGS. MOISTENING FROM THE TOP DOWN WILL ERODE THIS DRY LAYER WITH SOUNDINGS SHOWING SATURATION BY MIDDAY FOR LIGHT SNOW TO REACH THE GROUND NEAR THE COAST. NO CHANGES TO CURRENT FORECAST. BLEND OF THE GUIDANCE SUGGESTS AN INCH OR 2 POSSIBLE OVER CAPE COD AND POSSIBLY INTO SE PLYMOUTH COUNTY...WITH UP TO 3 INCHES AT ACK WHERE DECENT OMEGA IS PRESENT IN THE SNOW GROWTH REGION. WEST OF THE CANAL EXPECTING A COATING TO AN INCH NEAR THE COAST. HIGH TEMPS TODAY WILL ONLY BE IN THE UPPER TEENS TO MID 20S...EXCEPT NEAR 30 ACROSS THE CAPE/NANTUCKET. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... TONIGHT AND FRIDAY... SPRAWLING HIGH PRESSURE ACROSS THE CENTRAL PLAINS BUILDS INTO SOUTHERN NEW ENGLAND TONIGHT AND FRIDAY. MAINLY DRY WEATHER EXPECTED...BUT A FEW LINGERING FLURRIES/LIGHT SNOW SHOWERS CAN/T BE RULED OUT ACROSS THE OUTER-CAPE TONIGHT. SHOULD SEE A LOT OF CLOUDS TONIGHT...BUT MAY SEE THEM SCATTER OUT LATE AS DRIER AIR WORKS IN FROM THE WEST. IT WILL BE QUITE COLD WITH LOWS MAINLY IN THE SINGLE DIGITS TO LOWER TEENS. SOME OF THE COLDEST OUTLYING LOCATIONS MAY DROP BELOW ZERO...BUT THAT WILL DEPEND ON HOW MANY BREAKS DEVELOP IN THE CLOUD COVER. A MIXTURE OF CLOUDS AND SUNSHINE EXPECTED ON FRIDAY...BUT ONLY EXPECT HIGHS IN THE 20S WITH LIMITED MIXING. WINDS WILL BE RATHER LIGHT AND WITH SOME SUNSHINE EXPECTED...IT WILL FEEL AT LEAST A LITTLE MORE COMFORTABLE THEN TODAY. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... HIGHLIGHTS... * COLD AND MAINLY DRY FRIDAY THROUGH SUNDAY MORNING * CHANCE OF SNOW SUNDAY NIGHT INTO MONDAY * CHANCE OF SNOW POSSIBLY MIXING WITH RAIN TUESDAY NIGHT AND WEDNESDAY OVERVIEW AND MODEL PREFERENCES... WITH THE NAO/AO REMAINING POSITIVE FOR THE FORESEEABLE FUTURE...AS NOTED BY THE PREVIOUS FORECASTER...THE NEXT WEEK OR SO/S SENSIBLE WX IS LIKELY TO BE DEFINED BY WHAT HAPPENS IN THE SPLITTING FLOW REGIMES ACROSS THE WRN CONUS AND ERN PACIFIC. WITH SPLIT FLOW MERGING SOMEWHERE NEAR THE NE...IT WILL BE STRONGLY DEPENDENT ON WHETHER WAVES WITHIN THE SRN OR NRN STREAM REMAIN DOMINANT...SOMETHING GUIDANCE TYPICALLY DOESN/T HANDLE WELL UNTIL CLOSER TO THE EVENT. INITIALLY IN THE MID TERM...THE CONFLUENCE OF THESE STREAMS LOOKS TO BE TO OUR WEST...LEADING TO THE BUILDING OF NEARLY 1045+ HPA THROUGH THE WEEKEND. ALSO...IT SHEARS A NRN STREAM WAVE SUN NIGHT INTO MON...WEAKENING IT SOMEWHAT. THE SFC REFLECTION IS A COLD FRONT AND WHILE IT APPEARS THAT IT WILL HAVE WITH IT ENOUGH MOISTURE FOR WIDESPREAD SNOWFALLS...THE WEAKENING NATURE SUGGESTS THAT AMOUNTS ARE LIKELY TO BE AT OR BELOW ADVISORY LEVEL. TUE INTO WED...WILL LEAN AWAY FROM A 12Z ECMWF BLEND USING GFS/GEFS AND ECENS AS EVEN THE ENSEMBLES ARE NOT AS FAR SUPPRESSED WITH THE STORMTRACK AS THE DETERMINISTIC RUN. THIS IS A POTENTIALLY WETTER SOLUTION. HOWEVER...GIVEN THE FACT THAT IT WILL DEPEND ON WHETHER THE STREAMS PHASE OR ONE DOMINATES...WILL HAVE TO WAIT AND SEE BEFORE THERMAL PROFILES ARE DEFINED. DETAILS... FRI NIGHT INTO SUN... INITIALLY COLD HIGH PRES WILL BE MOVING ACROSS THE REGION...CRESTING EARLY SUN MORNING. THIS SUGGESTS TEMPS GENERALLY BELOW NORMAL FRI NIGHT INTO SAT NIGHT WITH SOME MODERATION DURING THE DAY SUN. DEEP SNOWPACK AND WEAK PRES GRADIENT SUGGEST GOOD RADIATIONAL COOLING. EXPECT MINS DIPPING INTO THE NEGATIVE DOUBLE DIGITS IN THE COLD NW...TO NEAR 0 FOR INTERIOR EA MA/RI AND CT. HIGHS ON SAT MAINLY IN THE TEENS AND LOW 20S...TO THE 20S AND NEAR FREEZING BY SUN AFTERNOON. SUN NIGHT INTO MON... COLD FRONT MOVES ACROSS THE REGION WITH ENOUGH ISENTROPIC LIFT IN ADVANCE AND F-GEN NEAR TO THE FRONT ITSELF TO YIELD LIGHT- MODERATE PRECIP ACROSS THE AREA. AT THIS POINT IT APPEARS THAT THERMAL PROFILES WOULD SUPPORT ALL SNOW. QPF VALUES RANGE FROM ABOUT 0.2 TO 0.5 INCHES TOTAL...SO GIVEN THERE IS AT LEAST MODEST LIFT IN THE SNOW GROWTH REGION ALOFT...SUSPECT SOME AREAS WILL APPROACH WINTER WX ADVISORY CRITERIA. SNOWS COME TO AN END TUE AFTERNOON. MON NIGHT INTO TUE... BRIEF RIDGE OF HIGH PRES FOLLOWS BUT IS SHORT LIVED DUE TO PROGRESSIVE PATTERN ALOFT. TEMPS REMAIN BELOW ZERO...BUT NOT AS COLD AS PREVIOUS DAYS. TUE NIGHT INTO WED... AS MENTIONED ABOVE...THIS IS A TRICKY FORECAST REGARDING A STREAM PHASING SCENARIO AND STRONGER LOW PRES WITH CONNECTION TO THE SUBTROPICS. GUIDANCE SUGGESTING THAT PWATS COULD BE 2-3 STD DEVIATIONS ABOVE NORMAL. HOWEVER...TRACK REMAINS UNCERTAIN. GFS CONTINUES TO SHOW INSIDE RUNNER WITH ENERGY TRANSFER TO OFFSHORE LOW...WHILE THE 00Z ECMWF HAS COME FURTHER N...BUT IS COLDER /ALTHOUGH STILL WARMER THAN THE 12Z/ AS MENTIONED IN THE MODEL DISCUSSION...WILL CONTINUE TO LEAN AWAY FROM ECMWF AT 12Z...BUT WILL ADD IN SOME OF THE 00Z ECMWF TO THE BLEND FOR THERMALS. WILL NEED TO KEEP AN EYE ON THIS EVENT HAS THE POTENTIAL TO BE A MIXED P-TYPE EVENT WITH MODERATE-HIGH IMPACT GIVEN THE AVAILABLE MOISTURE AND STRONGER POTENTIAL DYNAMICS. THU... UNCERTAIN BECAUSE OF DIFFICULTY IN NAILING DOWN THE FINAL STREAM DOMINANCE. CHANCE FOR FURTHER STORMS IF THE NRN STREAM DOMINATES...MORE SUPPRESSED PATTERN IF THE SRN STREAM DOMINATES. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TODAY THROUGH FRIDAY/... TODAY...MODERATE CONFIDENCE. CIGS GRADUALLY LOWER THROUGH THE MORNING...WITH THE POSSIBILITY OF MVFR CIGS AT ALMOST ALL SITES BY EARLY AFTERNOON. SOME LIGHT SNOW SHOWERS POSSIBLE ANYWHERE THIS AFTERNOON WITH BRIEF MVFR VSBYS. THE BEST CHANCE FOR A LONGER PERIOD OF SN IS SE OF AN IJD-OWD LINE...WHERE EVEN BRIEF IFR CONDITIONS CAN/T BE RULED OUT. ACCUMS GENERALLY LIGHT...MAINLY 1-2 INCHES AT MOST...EXCEPT POSSIBLY A LITTLE HIGHER ON ACK. WINDS MAINLY N-NE. TONIGHT AND FRIDAY...MODERATE TO HIGH CONFIDENCE. MAINLY VFR CONDITIONS EXPECTED BUT SOME OCEAN EFFECT MVFR CIGS WILL PROBABLY AFFECT THE CAPE AND NANTUCKET FOR A TIME TONIGHT INTO FRI MORNING. KBOS TAF...MODERATE CONFIDENCE IN TAF. BRIEF PERIOD OF LIGHT SNOW SHOWERS/FLURRIES POSSIBLE LATER THIS MORNING INTO THIS AFTERNOON. ANY ACCUMS WOULD LIKELY BE A DUSTING TO LESS THAN AN INCH. KBDL TAF...MODERATE CONFIDENCE IN TAF. BRIEF PERIOD OF LIGHT SNOW SHOWERS/FLURRIES POSSIBLE LATER THIS MORNING INTO EARLY THIS AFTERNOON. ANY ACCUMS WOULD LIKELY BE NO MORE THEN A DUSTING TO LESS THAN AN INCH. OUTLOOK...FRIDAY NIGHT THROUGH MONDAY... FRIDAY NIGHT INTO SUNDAY...HIGH CONFIDENCE. MAINLY VFR. SUN NIGHT INTO MON...MODERATE CONFIDENCE. PERIODS OF IFR/MVFR IN SNOW ACROSS THE REGION. WINDS SHIFT FROM SLY TO WLY...WITH GUSTS 20-25 KT AT TIMES DURING THE DAY MON. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TODAY THROUGH FRIDAY/...HIGH CONFIDENCE. TODAY THROUGH FRIDAY...HIGH CONFIDENCE. LOW PRESSURE PASSING WELL SOUTHEAST OF THE BENCHMARK WILL ALLOW FOR NORTHEAST WIND GUSTS OF 20 TO 30 KNOTS TO DEVELOP LATER THIS MORNING AND CONTINUE INTO EARLY THIS EVENING. A PERIOD OF SNOW...MAINLY ACROSS THE SOUTHEAST WATERS MAY RESULT IN VISIBILITIES 1 MILE OR LESS FOR A TIME LATER THIS MORNING INTO THIS AFTERNOON. WINDS SHOULD DIMINISH BY LATER THIS EVENING AND REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS INTO FRIDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. HOWEVER...SMALL CRAFT SEAS WILL CONTINUE ACROSS THE OUTER-WATERS THROUGH FRIDAY AFTERNOON. OUTLOOK...FRIDAY NIGHT THROUGH MONDAY... FRI NIGHT THROUGH SUN...HIGH CONFIDENCE. A PERIOD OF MAINLY QUIET BOATING WEATHER IS EXPECTED AS HIGH PRES BUILDS OVER THE WATERS. A RISK FOR LIGHT FREEZING SPRAY IS POSSIBLE DURING THE OVERNIGHT HOURS. SUN NIGHT INTO MON...MODERATE CONFIDENCE. LOW PRES WILL BRING A PERIOD OF SNOW MIXING WITH RAIN ESPECIALLY ON THE SRN WATERS. WINDS BEGIN OUT OF THE S THEN SHIFT TO THE W...INCREASING WITH GUSTS APPROACHING GALE FORCE POSSIBLE BY LATER SUN. SEAS INCREASE AS WELL. WILL LIKELY NEED AT LEAST SMALL CRAFT ADVISORIES IF NOT GALES. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ231>235-237-251. SMALL CRAFT ADVISORY UNTIL 7 PM EST FRIDAY FOR ANZ250-254>256. && $$ SYNOPSIS...FRANK/DOODY NEAR TERM...FRANK/DOODY SHORT TERM...KJC/FRANK LONG TERM...DOODY AVIATION...FRANK/DOODY MARINE...FRANK/DOODY

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