Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBOX 171925 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 225 PM EST WED DEC 17 2014 .SYNOPSIS... SCATTERED RAIN OR SNOW SHOWERS ARE POSSIBLE TONIGHT AS AN UPPER LEVEL DISTURBANCE CROSSES NEW ENGLAND. HIGH PRESSURE BUILDING INTO THE REGION WILL BRING DRY WEATHER THURSDAY AND FRIDAY. LOW PRESSURE MAY IMPACT SOUTHERN NEW ENGLAND EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... 225 PM UPDATE... SEEING A FEW BREAKS IN CLOUD COVER ACROSS SOUTHERN NEW ENGLAND THIS AFTERNOON...BUT EXPECT THESE TO FILL BACK IN AS WE APPROACH SUNSET DUE TO LEFTOVER MOISTURE AND PRESENCE OF UPPER LEVEL TROUGH OVER REGION. STILL LOOKING AT DRY WEATHER THROUGH AT LEAST THIS EVENING PER HIGH-RES MODELS...BEFORE SCATTERED RAIN/SNOW SHOWERS DEVELOP EARLY TONIGHT IN RESPONSE TO APPROACHING SHORT WAVE. MOST OF THIS ACTIVITY SHOULD BE FOCUSED NORTH OF MASS PIKE...BUT COULD SEE A FEW RAIN OR SNOW SHOWERS INTO PARTS OF N CT...RI AND SE MA AS WELL. NOT LOOKING OVERLY IMPRESSIVE FOR ANY SNOW SQUALLS PER BTV 4KM WRF AND OTHER HIGH-RES MODELS. DESPITE PRESENCE OF MOISTURE AND UPPER TROUGH MOVING THROUGH NEW ENGLAND...LACKING GOOD INSTABILITY AND LAPSE RATES. SO OUR THINKING IS WE WILL SEE DUSTING TO PERHAPS AN INCH OF ACCUMULATION OF SNOW AT MOST...MAINLY ACROSS HIGHER TERRAIN. LOWS TONIGHT WILL DROP BACK INTO 30S...WITH FREEZING LINE PROBABLY STAYING JUST W OF I-495 CORRIDOR IN E MA BY DAYBREAK THU. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... EXPECT TO SEE FEW LINGERING SNOW SHOWERS THU MORNING ACROSS NE MA AS SYSTEM DEPARTS. OTHERWISE DRY WEATHER WILL PREVAIL THU AND THU NIGHT. GUSTY W/NW WINDS /30-35 MPH/ ANTICIPATED AS A RESULT OF LOW PRESSURE DEEPENING OVER MARITIMES. THIS SHOULD HELP TO SCOUR OUT CLOUDINESS A BIT...BUT DO NOT EXPECT TOTAL CLEARING AS UPPER TROUGH STILL HANGS BACK FROM NEW ENGLAND TO GREAT LAKES...EVEN THROUGH THU NIGHT. STAYED CLOSE TO BLEND OF MODEL GUIDANCE WHICH RESULTS IN HIGHS FROM UPPER 30S NW TO MID 40S SE THU...AND LOWS MAINLY IN 20S THU NIGHT. && .LONG TERM /FRIDAY THROUGH TUESDAY/... HIGHLIGHTS... * DRY WEATHER AND AT OR BELOW AVG TEMPS FRIDAY INTO SAT * WEAK WAVE OF LOW PRESSURE ON SUNDAY INTO MONDAY * ANOTHER SYSTEM POSSIBLE NEXT WED OR THURSDAY OVERVIEW... OVERALL 00Z GUIDANCE IS IN AGREEMENT SYNOPTICALLY. ACTIVE SPLIT-FLOW PATTERN OVER THE CONUS WILL TRANSITION TO A MORE AMPLIFIED RIDGE/TROUGH WITH A POSSIBLE NEGATIVELY TILT TROUGH SETTING UP OVER THE GREAT LAKES BY CHRISTMAS EVE. THIS IS THE BEGINNING OF THE PATTERN SHIFT WHICH COULD PUT THE REGION IN A MORE ACTIVE PATTERN FOR THE END OF THE MONTH. GUIDANCE TENDS TO HAVE ISSUES WITH THE PATTERN SHIFT AS WELL AS PHASING SO TIMING ON ANY SYSTEMS MAY SLOW DOWN OR EVEN SPEED UP. WHILE WE ARE IN TRANSITION...RIDGING WILL MOVE INTO THE REGION FRIDAY INTO SATURDAY. DIGGING SHORTWAVE ACROSS THE TENNESSEE VALLEY WILL DEVELOP A WEAK LOW PRESSURE SYSTEM BRINGING PRECIP TO THE AREA SUNDAY INTO MONDAY. ANOTHER STRONG TROUGH WILL DIG INTO THE SOUTHERN CONUS BRINGING ANOTHER LOW PRESSURE TOWARDS NEW ENGLAND AROUND THE CHRISTMAS TIMEFRAME. FOR NOW TRENDED TOWARDS THE ENSEMBLES FOR THIS FORECAST BECAUSE OF THE AMOUNT OF UNCERTAINTY. DETAILS... FRIDAY INTO SATURDAY...HIGH CONFIDENCE. AS UPPER LEVEL LOW SPINS INTO THE MARITIMES...HIGH PRESSURE WILL BUILD INTO SOUTHERN NEW ENGLAND. THIS WILL ALLOW FOR QUIET AND DRY WEATHER. TEMPERATURES WILL HOVER NEAR AVERAGE DURING THIS TIME PERIOD. ONSHORE FLOW SATURDAY NIGHT WITH APPROACHING SYSTEM FROM THE SOUTH MAY LEAD TO SOME DRIZZLE/FOG MOVING IN FROM THE OCEAN TO THE EAST MASS COASTLINE. SUNDAY INTO MONDAY...LOW CONFIDENCE. MAIN FOCUS OF THE FORECAST WAS ON THIS TRICKY TIME PERIOD. THE MODELS/ENSEMBLES HAVE OFFERED A VARIETY OF SOLUTIONS OVER THE PAST FEW DAYS FROM A VERY LOW AMPLITUDE AND FLAT WAVE MOVING THROUGH THE SOUTHEAST TO A WRAPPED UP SFC LOW HUGGING THE COAST INTO NEW ENGLAND. 00Z MODELS CONTINUE TO DO A SLIGHT SHIFT IN DEVELOPING THIS SYSTEM FAR ENOUGH OFFSHORE TO HAVE LOW IMPACTS ALONG THE COAST... BUT COULD THROW SOME LIGHT RAIN/SNOW BACK INTO THE MID- ATLANTIC/NORTHEAST AS IT EXITS INTO THE ATLANTIC. WILL NEED TO CONTINUE TO MONITOR THIS SYSTEM AS A FEW MEMBERS OF THE GEFS AS WELL AS THE CANADIAN AND ECMWF ENSEMBLES STILL SHOW THIS STORM NEAR THE BENCHMARK. RIGHT NOW APPEARS THAT MOISTURE WILL STREAM INTO THE REGION ON SUNDAY ALLOWING FOR LIGHT PRECIP WITH A CHANCE FOR MORE SHOWERS LATE SUNDAY INTO MONDAY. STILL A LOW CONFIDENCE AS EXACT TIMING OF THIS SYSTEM REMAINS IN QUESTION DUE TO HIGH MODEL SPREAD. TUESDAY AND BEYOND...LOW CONFIDENCE. ANTICIPATE DRY AIR TO WORK ITS WAY INTO THE REGION BEHIND THE DEPARTING SYSTEM ON TUESDAY. STRONG SHORTWAVE WILL DIG WELL INTO THE SOUTHERN CONUS EARLY NEXT WEEK DEVELOPING A STRONG LOW PRESSURE SYSTEM BY WEDNESDAY. WE COULD BEGIN TO SEE IMPACTS FROM THIS SYSTEM BY WEDNESDAY BUT EXACT DETAILS REMAIN UNCERTAIN. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH THURSDAY NIGHT/...MODERATE CONFIDENCE. MVFR CIGS WILL PREVAIL THROUGH THIS EVENING. CIGS LIFT TO VFR ACROSS MOST OF AREA TONIGHT WITH INCREASING W/NW WINDS...GUSTING TO 25KT ESPECIALLY NEAR COAST. ALSO EXPECT SCATTERED RAIN/SNOW SHOWERS...MAINLY ACROSS NORTHERN MA WITH BRIEF MVFR CIGS/VSBYS. VFR CIGS DOMINATE THU AFTER LEFTOVER MVFR CIGS DURING MORNING... PERHAPS SCATTERED RAIN/SNOW SHOWERS ACROSS NE MA. NW WINDS GUST AS HIGH AS 25-30KT. KBOS TERMINAL...MODERATE CONFIDENCE. LOW-END MVFR CIGS THROUGH EVENING PUSH. COULD SEE CIGS IMPROVE TO OVC025 AS BEST CASE...BUT NOT LIKELY AT THIS TIME. KBDL TERMINAL...HIGH CONFIDENCE. OUTLOOK...FRIDAY THROUGH SUNDAY... FRIDAY THROUGH SATURDAY...HIGH CONFIDENCE. VFR CONDITIONS EXPECTED. SUNDAY...LOW CONFIDENCE. DEVELOPING MVFR CONDITIONS ESP ACROSS THE EASTERN MASS COASTLINE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...MODERATE CONFIDENCE. SCA REMAINS POSTED FOR ALL WATERS THROUGH THU...AND FOR OUTER WATERS THROUGH THU NIGHT. LOW PRESSURE DEEPENING OVER MARITIMES WILL RESULT IN STRONG W/NW WINDS ACROSS WATERS...SOLIDLY 25-30KT GUSTS WITH OUTSIDE CHANCE OF SOME 35KT GUSTS ON OUTER WATERS. HOWEVER WE ARE NOT CONFIDENT ENOUGH TO UPGRADE TO GALE WARNINGS AT THIS TIME. PEAK GUSTS SHOULD OCCUR LATE TONIGHT THROUGH THU AFTERNOON. WINDS GRADUALLY SUBSIDE THU NIGHT BUT SEAS WILL TAKE A BIT LONGER TO DIMINISH. MAY SEE SCATTERED RAIN/SNOW SHOWERS ON E MA WATERS LATE TONIGHT INTO THU MORNING...ESPECIALLY NEAR CAPE ANN AND MERRIMACK RIVER. OUTLOOK...FRIDAY INTO SUNDAY...MODERATE TO HIGH CONFIDENCE. ANTICIPATE DIMINISHING WINDS AND SEAS INTO SATURDAY LEADING TO BELOW SMALL CRAFT ADVISORY LEVELS. CONTINUE TO MONITOR THE POTENTIAL FOR A COASTAL STORM FOR SUNDAY INTO MONDAY. THERE IS A LARGE UNCERTAINTY IN THE TRACK AND INTENSITY OF THIS SYSTEM AND ANY CORRESPONDING IMPACT ON WINDS AND SEAS IN THE COASTAL WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR ANZ232>235- 237-250-254>256. SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST THURSDAY FOR ANZ230-236. SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR ANZ231-251. && $$ SYNOPSIS...EVT/JWD NEAR TERM...JWD SHORT TERM...JWD LONG TERM...DUNTEN AVIATION...EVT/JWD MARINE...EVT/JWD

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.