Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Text Only | 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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBOX 280838 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 338 AM EST FRI NOV 28 2014 .SYNOPSIS...
-- Changed Discussion --
A TROUGH OF LOW PRESSURE ACROSS EASTERN NEW ENGLAND EXTENDS NORTHWEST FROM A LOW ABOUT 400 MILES SOUTHEAST OF NANTUCKET. THIS FEATURE WILL RESULT IN A PERIOD OF SNOW THIS MORNING ACROSS EASTERN MASSACHUSETTS AND SOUTHEAST NEW HAMPSHIRE. DRY BUT COLDER WEATHER THEN OVERSPREADS THE REGION THIS AFTERNOON AND TONIGHT. HIGH PRESSURE PROVIDES DRY BUT CHILLY WEATHER SATURDAY. A WARM FRONT CROSSES THE AREA SATURDAY NIGHT WITH A LIGHT WINTRY MIX OF PRECIPITATION POSSIBLE. BEHIND THE FRONT MUCH MILDER WEATHER IS ON TAP FOR SUNDAY AND MONDAY. A POLAR FRONT WILL THEN SWEEP ACROSS THE REGION LATER MON BRINGING A RETURN TO COLDER WEATHER TUE. A WARM FRONT MAY THEN BRING ANOTHER RISK OF WINTRY PRECIPITATION THE MIDDLE OF NEXT WEEK.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1 AM UPDATE... BAND OF RAIN/SNOW DEVELOPING AS SEEN ON LAST FEW SHORT RANGE MODEL RUNS COMING TOGETHER ACROSS E MA INTO SE NH. LOOKS LIKE INVERTED TROUGH SETTING UP IN A NNW-SSE ORIENTATION FROM NEAR KMHT-KGHG-KCQX AS SEEN ON LATEST NE REGIONAL 88D RADAR TRENDS. IR SATELLITE ALSO SHOWING THE DEVELOPING LOW PRES SE OF NANTUCKET WHICH THIS TROUGH IS EMANATING...AND ALSO SHOWING THE TROUGH EXTENDING FROM S CENTRAL NH SE TO CAPE COD AT 05Z. INTERESTING NOTE...TEMP AT KFMH AT 32 WITH LIGHT NW WIND WHILE LIGHT N WIND CONTINUE AT KPVC WITH A TEMP OF 41...SO GOOD BAROCLINIC ZONE SETTING UP. PLUS...JUST CAUGHT THE LATEST WEBCAM LOOP FROM MANCHESTER NH...ROADWAYS WENT FROM WET TO WHITE OVER THE LAST FEW HOURS. VSBYS ARE DROPPING IN SOME OF THE STEADIER SNOW ACROSS NE MA/S CENTRAL NH AS WELL AS ALONG THE IMMEDIATE E COAST. WILL CONTINUE TO SEE THIS TREND DOWNWARD AS AREA OF PRECIP BECOMES BETTER ORGANIZED. WHERE THE BACK EDGE OF THIS PRECIP SETS UP STILL IN QUESTION...WILL MONITOR THIS ASPECT AND ADJUST TRENDS ACCORDINGLY. HAVE INCREASED POPS ALONG THE E COAST TO CATEGORICAL...AND LIKELY AS FAR W AS S CENTRAL NH AND ALONG THE I-495 BELTWAY. CUT OFF THE PRECIP SHARPLY FURTHER W AFTER 07Z-08Z AS LEFTOVER PRECIP FROM FIRST SHORT WAVE ENDS. WILL KEEP AN EYE ON INCREASING INTENSITY OF PRECIP OVER THE NEXT FEW HOURS AND DECIDE WHETHER EXTENSION OF THE ADVISORY A BIT FURTHER TO THE W MAY BE NECESSARY. REMAINDER OF GRIDS WERE PRETTY GOOD BUT DID UPDATE TO BRING CURRENT. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... *** ACCUMULATING SNOW THROUGH MIDDAY ACROSS EASTERN MA FROM CAPE ANN TO BOSTON TO PORTIONS OF CAPE COD...POSSIBLY INTO S CENTRAL NH *** INVERTED TROUGH LOOKS TO PRODUCE MOD TO HVY SNOW FOR A TIME AFTER SUNRISE THROUGH LATE MORNING...THEN SHOULD PUSH BEGIN TO PUSH OFFSHORE BY AROUND MIDDAY. SHORT RANGE MODELS HAVE DONE RATHER WELL WITH THIS TIMING...BUT STILL SOME QUESTION AS TO HOW FAR W OR E THIS WILL ULTIMATELY SET UP. STILL NOTING IMPRESSIVE TOTAL TOTALS...ON ORDER OF 50-55 ON THE 00Z NAM RUN THROUGH 15Z-18Z THEN SHIFTS OFFSHORE. WILL NEED TO EXAMINE 00Z GFS BEFORE DECIDING UPON ADDING ANY ZONES TO THE CURRENT ADVISORY. FOR NOW...WILL ISSUE SPECIAL WEATHER STATEMENT FOR THE AREAS FROM S CENTRAL NH AND MOST OF E MA. && .LONG TERM /SATURDAY THROUGH THURSDAY/...
-- Changed Discussion --
UPDATED 340 AM HIGHLIGHTS... * CHILLY BUT DRY SATURDAY * MUCH MILDER SUNDAY AND MONDAY * RETURN TO CHILLY WEATHER TUESDAY SYNOPTIC OVERVIEW AND MODEL GUIDANCE EVALUATION... 00Z GEFS AND ECENS ENSEMBLES IN GOOD AGREEMENT ON THE LARGE SCALE FLOW ACROSS NORTH AMERICA THIS PERIOD OFFERING A TYPICAL LATE FALL WEATHER PATTERN...AN AMPLIFIED BUT PROGRESSIVE NORTHERN STREAM. THIS RESULTS IN LARGE DAILY TEMPERATURE VARIATIONS ACROSS SOUTHERN NEW ENGLAND THIS PERIOD. AS FOR THE DETERMINISTIC RUNS OF THE 00Z GFS AND ECMWF...OTHER THAN TYPICAL TIMING /GFS FASTER WITH FROPA MON/ AND AMPLTIUDE DIFFERENCES AT THIS TIME RANGE THESE MODELS ARE IN GOOD AGREEMENT WITH THEIR ENSEMBLE COUNTERPARTS. THUS WILL USE A MODEL BLEND AS A BASELINE FOR THIS PORTION OF THE FORECAST. DAILY SENSIBLE WEATHER DETAILS... SATURDAY...COLD START TO THE DAY AFTER GOOD RADIATIONAL COOLING TONIGHT. HIGHS ONLY EXPECTED IN THE MU30S...WITH U20S AND L30S ACROSS THE HIGHER TERRAIN. THESE TEMPS ARE 10-15 DEGS COLDER THAN NORMAL. HOWEVER PARTLY SUNNY CONDITIONS ALONG WITH LIGHT WINDS WILL TAKE SOME OF THE EDGE OFF THE CHILLY TEMPS. SATURDAY NIGHT...WARM FRONT APPROACHES THE REGION. THUS INCREASING CLOUDS WITH THE CHANCE OF SOME SPOTTY LIGHT PRECIP. MODEL SOUNDINGS SUGGEST ANY LIGHT PRECIP WOULD BEGIN AS LIGHT SNOW OR FLURRIES THEN TRANSITIONING TO SLEET...FREEZING RAIN BEFORE ALL RAIN. COLUMN STRUGGLES TO SATURATE SO ANY PRECIP SHOULD LIGHT AND SPOTTY. HENCE NOT A HIGH IMPACT EVENT. SUNDAY AND MONDAY... SUBTROPICAL RIDGE BRIEFLY BUILDS ACROSS THE SOUTHEAST STATES AND THIS YIELDS MILDER AIR STREAMING NORTHWARD UP THE EASTERN SEABOARD INTO NEW ENGLAND WITH HIGHS INTO THE 50S ACROSS RI AND EASTERN MA BOTH DAYS. POLAR COLD FRONT MAY YIELD THE RISK FOR A FEW RAIN SHOWERS /POSSIBLE ENDING AS SNOW SHOWERS/ LATE MON/MON NIGHT. AS MENTIONED ABOVE ECMWF SLOWER WITH FROPA THAN GFS. GIVEN TIME RANGE WILL FOLLOW A MODEL BLEND. TUESDAY...1042 MB HIGH AND ITS ASSOCIATED POLAR AIRMASS SETTLE OVER NEW ENGLAND TUE WITH TEMPS NEARLY 20 DEGS COLDER THAN MON! HIGHS ONLY IN THE 30S...MU20S HIGHER TERRAIN. WEDNESDAY...OVERRUNNING PRECIP POSSIBLE WITH A WINTRY MIX GIVEN COLD AIR WILL INITIALLY BE SLOW TO DISLODGE. THURSDAY...TREND IS FOR DRIER BUT A RETURN TO COLDER WEATHER.
-- End Changed Discussion --
&& .AVIATION /09Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM /THROUGH TONIGHT/...MODERATE CONFIDENCE. THROUGH 12Z...MVFR-IFR CIGS HAVE STARTED TO DEVELOP ACROSS S CENTRAL NH INTO NE MA AND SHOULD LOWER AS PRECIP BECOMES BETTER ORGANIZED BY 08Z-10Z ACROSS MOST OF E MA...POSSIBLY AS FAR W AS KFIT-KSFZ-KUUU. VSBYS ALSO DROPPING FROM KMHT-KLWM TO IFR. WILL ALSO TREND CIGS/VSBYS DOWNWARD ACROSS E MA/E RI TERMINALS OVERNIGHT. ACROSS CENTRAL-W AREAS...MAINLY VFR WITH LOCAL MVFR CIGS/VSBYS IN LOCAL SNOW SHOWERS MAINLY ACROSS SW NH/N CENTRAL MA. TODAY...EXPECT AREA OF MAINLY SNOW...SOME OF WHICH MAY FALL MODERATELY AT TIMES...ACROSS S CENTRAL NH/E MA INTO E RI. VSBYS MAY BRIEFLY LOWER TO LIFR IN BRIEF PERIODS OF MOD-HVY SNOW. WILL SEE MIXED RAIN/SNOW ALONG COAST S OF BOSTON TO CAPE COD AND ISLANDS. CONDITIONS SHOULD BEGIN TO IMPROVE FROM W-E AROUND 16Z- 18Z AS TROUGH MOVES OFFSHORE. FURTHER INLAND...EXPECT MAINLY VFR. TONIGHT...MAY SEE LEFTOVER MVFR CONDITIONS ALONG E COAST WHICH SHOULD IMPROVE BY 02Z-03Z...OTHERWISE VFR. KBOS TERMINAL...MODERATE CONFIDENCE MAINLY FOR TIMING OF MVFR-IFR CONDITIONS THROUGH MIDDAY...THEN WHEN IMPROVING CONDITIONS MOVE IN. HIGH CONFIDENCE TONIGHT. KBDL TERMINAL...HIGH CONFIDENCE. OUTLOOK...SATURDAY THROUGH TUESDAY...MODERATE CONFIDENCE. UPDATED 340 AM SATURDAY...VFR. INCREASING SKY COVER SATURDAY. NORTHWEST WINDS BECOME SOUTHWEST BUT REMAIN LIGHT. SATURDAY NIGHT-SUNDAY...LOWERING CLOUDS SATURDAY NIGHT WITH POTENTIAL FOR MVFR CIGS/VSBYS IN WIDELY SCATTERED PCPN LATE AT NIGHT AND SUNDAY MORNING. LOW LEVEL WINDS...AROUND 2000 FEET...WILL INCREASE OVERNIGHT AND SUNDAY TO 40-45 KNOTS AND MAY CREATE LOW LEVEL WIND SHEAR. MONDAY...VFR WITH SCATTERED SHOWERS LATE OR AT NIGHT AS A COLD FRONT MOVES THROUGH. SOUTHWEST WINDS AHEAD OF THE COLD FRONT WILL SWITCH TO NORTHWEST AFTER THE FRONT MOVES THROUGH. TUESDAY...VFR WITH NORTH TO NORTHEAST WINDS. TUESDAY...VFR WITH NORTH TO NORTHEAST WINDS.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM /TODAY/...HIGH CONFIDENCE. OVERNIGHT...STILL NOTING SEAS UP TO 7 FT ON THE EASTERN WATERS AT 02Z...BUT APPEAR TO BE SUBSIDING. HAVE KEPT SMALL CRAFTS GOING. OTHERWISE CONTINUED TRENDS FROM PREVIOUS FORECAST WITH SEAS SUBSIDING EARLY...THEN BEGINNING TO BUILD AGAIN LATE AS LOW PRES PASSES S OF THE WATERS. WILL ALSO SEE N-NW WINDS THAT MAY BECOME NE ALONG THE COAST BUT REMAIN LIGHT THOUGH GUSTS INCREASE TOWARD DAYBREAK. TODAY...WINDS INCREASE...GUSTING TO NEAR 25 KTS. HAVE SMALL CRAFT ADVISORIES UP FOR MOST OF THE COASTAL WATERS FOR EITHER SEAS...GUSTY WINDS OR BOTH. OUTLOOK...TONIGHT THROUGH TUESDAY...MODERATE CONFIDENCE. SATURDAY...HIGH PRES OVER THE WATERS EARLY THEN SLIDES OFFSHORE SAT NIGHT. THUS FAIRLY LIGHT WINDS ALONG WITH DRY WEATHER DURING THE DAY. RISK OF A FEW SHOWERS OF RAIN AND SNOW AT NIGHT. SUNDAY...WARM FRONT LIFTS NORTH THRU THE REGION. MODEST SW WIND DEVELOPS BUT MAINLY DRY WEATHER. MONDAY...COLD FRONT REMAINS WEST OF NEW ENGLAND SO MODEST SW WINDS CONTINUE. TUE...COLD HIGH PRES DRIFTS ACROSS SOUTHERN QUEBEC.
-- End Changed Discussion --
&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MAZ007-015- 016-019. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ235- 237-250-251-254>256. && $$ SYNOPSIS...NOCERA NEAR TERM...EVT SHORT TERM...RLG LONG TERM...NOCERA AVIATION...NOCERA/RLG/EVT MARINE...NOCERA/RLG/EVT

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