Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 311927 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 327 PM EDT FRI OCT 31 2014 .SYNOPSIS...
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DRY AND SEASONABLE CONDITIONS WILL CONTINUE TODAY AS HIGH PRESSURE MOVES ACROSS NORTHERN NEW ENGLAND. A DEVELOPING COASTAL STORM WILL MOVE UP THE COAST SATURDAY AND PASS OFFSHORE SATURDAY NIGHT AND EARLY SUNDAY BRINGING HIGH WINDS AND RAIN TO THE REGION. HIGH PRESSURE BUILDS OVER THE EASTERN USA EARLY NEXT WEEK. ONE OR TWO COLD FRONTS MAY CROSS SOUTHERN NEW ENGLAND WEDNESDAY THROUGH FRIDAY.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/... 130 PM UPDATE...DID NOT MAKE ANY MAJOR CHANGES TO THE FORECAST AT THIS TIME. UPDATED WINDS AND POPS THROUGH THE PERIOD BUT DID NOT STRAY FAR FROM THE MORNING UPDATE...ONLY INCORPORATED NEW GUIDANCE WHICH IS ON TRACK WITH EARLIER GUIDANCE. WILL BE LOOKING CLOSER AT TEMPERATURES AND WEATHER /ANY P-TYPE ISSUES/ FOR THE REMAINDER OF THE AFTERNOON. CURRENT WEATHER IS ON TRACK WITH TEMPERATURES IN THE UPPER 40S TO LOW 50S AS OF 1 PM. ***UPDATES MADE TO WEEKEND STORM*** 1015 AM UPDATE...BASED ON LATEST MODEL GUIDANCE HAVE INCREASED WINDS FOR THE SATURDAY TO SUNDAY TIME PERIOD. WHILE THERE IS STILL A BIT OF UNCERTAINTY ON THE TRACK OF THE COASTAL LOW...BELIEVE IT WILL BE CLOSE ENOUGH TO SOUTHERN NEW ENGLAND TO RESULT IN VERY GUSTY TO POSSIBLY DAMAGING WINDS FOR AT LEAST A PORTION OF THE REGION. THE HIGHEST CONFIDENCE FOR HIGH WINDS TO OCCUR IS OVER THE CAPE AND ISLANDS SATURDAY NIGHT AND SUNDAY. HOWEVER...WITH THE 06Z GFS BRINGING THE LOW A BIT CLOSER TO SOUTHERN NEW ENGLAND...HAVE ISSUED A HIGH WIND WATCH FOR ALL OF EASTERN MASSACHUSETTS AND RHODE ISLAND. OVERALL...THE FORECAST FOR TODAY IS ON TRACK...NO CHANGES WERE MADE TO THE FORECAST FOR TODAY. 745 AM UPDATE... ONLY MINOR TWEAKS TO THE FORECAST THIS MORNING. PREVIOUS DISCUSSION... AREA OF LOW TO MID LEVEL CLOUDS REMAIN ACROSS CENTRAL AND EASTERN AREAS AT 07Z...THOUGH NOTING SOME CLEARING ACROSS THE CT VALLEY AS WELL AS ALONG THE S COAST ON LATEST IR SATELLITE LOOP. NAM AND GFS BUFKIT SOUNDINGS INDICATING THAT THE 5-6KFT CEILINGS MAY BREAK UP BRIEFLY AROUND MID TO LATE MORNING BEFORE REDEVELOPING AS NE WINDS BRING IN INCREASING LOW LEVEL MOISTURE DURING THE AFTERNOON... AGAIN ACROSS CENTRAL AND EASTERN AREAS. LOW PRES MOVES SE OUT OF THE GREAT LAKES...THEN SECONDARY DEVELOPMENT BEGINS OFF THE MID ATLC COAST. LOOKS LIKE MOST OF THE DEEP MOISTURE WITH THE CYCLOGENESIS WILL REMAIN S OF THE REGION SO HAVE KEPT A DRY FORECAST GOING. MAY SEE SOME SPRINKLES AND PATCHY DRIZZLE DEVELOP LATE IN THE DAY ALONG THE E COAST...BUT NOT ENOUGH TO MENTION AT THIS POINT. EXPECT TEMPS TO ONLY RISE TO THE UPPER 40S ACROSS THE HIGHER INLAND TERRAIN...THEN MAINLY IN THE 50S ELSEWHERE WITH THE FRESHENING E-NE WINDS ESPECIALLY DURING THE AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... TONIGHT...SHORT RANGE MODELS APPEAR TO BE IN BETTER AGREEMENT IN THE DEVELOPMENT OF NOT ONE BUT TWO CENTERS OF LOW PRES AS H5 LONG WAVE TROUGH DIGS ACROSS THE SE U.S. NOTING TWO STRONG UPPER LEVEL JETS MOVING AROUND THE BASE OF THIS DIGGING TROUGH...THE FIRST 90-100 KT H3 JET AXIS WORKS NE OVERNIGHT. THIS WILL HELP INTENSIFY THE FIRST LOW OFF THE MID ATLC COAST AROUND 12Z SAT. AREA OF RAIN WILL WORK STEADILY NORTHWARD...ESPECIALLY AROUND OR AFTER MIDNIGHT. WILL ALSO SEE NE WINDS INCREASE ALONG THE COAST WITH GUSTS UP TO 25-30 KT...HIGHEST ALONG THE S COAST...CAPE COD AND THE ISLANDS. BEST SHOT FOR PRECIP WILL BE ACROSS RI/E MA. EXPECT OVERNIGHT LOWS TO RANGE FROM THE UPPER 30S OVER SW NH TO BETWEEN 45 AND 50 ALONG THE COAST. && .LONG TERM /SATURDAY THROUGH FRIDAY/...
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BIG PICTURE... THE LONG TERM PERIOD STARTS WITH A CLOSED LOW OVER THE NORTHEAST USA A TROUGH OVER THE ROCKIES...AND A RIDGE IN BETWEEN. THE CLOSED LOW LIFTS NORTHEAST INTO THE MARITIMES EARLY IN THE WEEK. THE RIDGE AND TROUGH TO OUR WEST MOVE EAST...BUT THE OVERALL FLOW BECOMES MORE ZONAL WITH TIME WITH A DETACHED SOUTHERN STREAM WAVE NEAR THE MEXICAN BORDER. HEIGHTS START THE PERIOD BELOW NORMAL DUE TO THE CLOSED LOW...THEN CLIMB TO NORMAL OR A LITTLE ABOVE NORMAL IN THE ZONAL FLOW. DEPENDING ON TIMING...COULD BE COOLING BACK TO BELOW NORMAL LATE IN WEEK. THIS SUGGESTS A COLD START TO THE WEEK BUT QUICKLY TRENDING BACK TO NORMAL MID WEEK...THEN COOLING AT END OF WEEK. ONCE THE UPPER FLOW BECOMES ZONAL...CONFIDENCE IN THE TIMING OF INDIVIDUAL WAVES IN THE FLOW AND THEIR ASSOCIATED SURFACE SYSTEMS WILL BE REDUCED. THE DAILIES... SUNDAY NIGHT-MONDAY-TUESDAY... THE AXIS OF THE UPPER LOW AND COLD POOL START SUNDAY NIGHT OVERHEAD AND MOVE OFF THROUGH THE MARITIMES BY MONDAY. DRIER AIR MOVES IN AT ALL LEVELS SUNDAY NIGHT AND REMAINS OVERHEAD MONDAY. FAIR MIXING SHOULD REACH TO AROUND 900 MB. TEMPS OF ZERO TO -1C AT THAT LEVEL TRANSLATE TO MAX SFC TEMPS INT HE UPPER 40S AND AROUND 50. THE HIGH MOVES OFF TO THE EAST TUESDAY WITH MILDER AIR MOVING IN ESPECIALLY ALOFT. CROSS SECTIONS SHOW INCREASING MOISTURE AT MID AND HIGH LEVELS...SO EXPECT SOME MID AND HIGH CLOUDS TOGETHER WITH THE SUN. TEMPS WARM UP A LITTLE BUT MIXING WILL BE SHALLOWER...950 MB TEMPS SUPPORT MAX TEMPS MID 50S. WEDNESDAY THROUGH FRIDAY... TWO SHORTWAVES MOVE ACROSS THE NORTHEAST AND EASTERN CANADA DURING MID TO LATE WEEK. THE FIRST WAVE LIFTS THROUGH QUEBEC WITH LIMITED CURVATURE IN NEW ENGLAND. THE SECOND WAVE DIGS DEEPER OVER THE GREAT LAKES AND SWEEPS ACROSS NEW ENGLAND 24-36 HOURS LATER THAN THE FIRST. AS THE UPPER FLOW IS ROUGHLY ZONAL...EXACT TIMING OF THE TWO PASSAGES IS LOW CONFIDENCE AT THIS TIME. WITH THE FIRST WAVE DIRECTED THROUGH CANADA AND THE UPPER FLOW REMAINING SOUTHWEST...THERE IS A GOOD CHANCE THE SURFACE FRONT STALLS OVER OR NEAR SOUTHERN NEW ENGLAND. THE SECOND DEEPER WAVE TURNS THE UPPER FLOW NORTHWEST AND SHOULD PUSH A COLD FRONT WELL OFFSHORE WITH COLDER AIR THEN FLOWING IN. WE WILL GO WITH CHANCE POPS NORTH OF THE PIKE LATE WEDNESDAY/NIGHT WITH THE FIRST WAVE AND FRONT...THEN MORE WIDESPREAD CHANCE POPS THURSDAY WITH THE SECOND WAVE AND FRONT. TIMING ON THIS WILL LIKELY CHANGE SOMEWHAT WITH SUCCESSIVE MODEL RUNS.
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&& .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
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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 SUNDAY/... THROUGH 00Z...HIGH CONFIDENCE. VFR. THERE ARE A FEW LOCATIONS ON THE CAPE AND ISLANDS THAT ARE HAVING PATCHY MVFR CIGS. TONIGHT...MODERATE CONFIDENCE. CONDITIONS DETERIORATE THROUGH THE NIGHT TO MVFR-IFR FROM SOUTH TO NORTH WITH LOWEST CONDITIONS ALONG THE COAST. EXPECT SCATTERED SHOWERS SOUTH OF THE MASS PIKE WITH THE GREATEST CHANCE OF STEADIER RAINFALL ALONG THE SOUTH COAST. SATURDAY THROUGH SUNDAY...MODERATE TO HIGH CONFIDENCE. MVFR/IFR CONDITIONS CONTINUE THROUGH 12Z SUNDAY WHEN CEILINGS START TO RISE FROM WEST TO EAST AS LOW PRESSURE PULLS AWAY FROM SOUTHERN NEW ENGLAND. NORTHEASTERLY WINDS INCREASE THROUGH THE PERIOD...PEAKING IN THE 40 TO 50 KT RANGE SATURDAY NIGHT INTO SUNDAY MORNING FOR THE EASTERN TERMINALS. WINDSPEEDS WILL BE LOWER ACROSS THE WESTERN TERMINALS BUT STILL GUSTING UP TO 35 TO 45 KTS PEAKING MORE ON SUNDAY. WIDESPREAD RAIN EXPECTED THROUGH SUNDAY MORNING MOST LOCATIONS AND CONTINUING ON THE EAST COAST...CAPE...AND ISLANDS INTO SUNDAY AFTERNOON. KBOS...HIGH CONFIDENCE IN TAF TRENDS. LOWER CONFIDENCE ON EXACT TIMING OF ONSET OF RAIN AND HIGHER WINDS. KBDL...HIGH CONFIDENCE IN TAF TRENDS. LOWER CONFIDENCE ON EXACT TIMING OF ONSET OF RAIN AND HIGHER WINDS. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...MODERATE CONFIDENCE SUNDAY NIGHT THROUGH TUESDAY...VFR. NORTHWEST WINDS MONDAY WILL GUST 25 TO 30 KNOTS DURING THE DAY. WEDNESDAY...VFR. POSSIBLE BRIEF MVFR CIGS/VSBYS IN SHOWERS LATE IN THE DAY AND AT NIGHT.
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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 TONIGHT/...HIGH CONFIDENCE. TODAY...WINDS AND SEAS REMAIN BELOW SMALL CRAFT CRITERIA. WINDS WILL VEER TO E-NE DURING THE DAY AND BEGIN TO PICK UP. GUSTS UP TO 20 KT REACH THE SOUTHERN OUTER WATERS BY LATE IN THE DAY. SEAS REMAIN BELOW 5 FT. TONIGHT...E-NE WINDS INCREASE WITH GUSTS UP TO 25-30 KT. SMALL CRAFTS REMAIN IN EFFECT FOR MOST OF THE WATERS...BUT NOT QUITE THERE FOR BOSTON HARBOR AND MASS/IPSWICH BAYS. SEAS WILL ALSO BUILD ESPECIALLY ON THE SOUTHERN OPEN WATERS DURING THE NIGHT. 1015 AM UPDATE...GIVEN THE LATEST FORECAST GUIDANCE...HAVE INCREASED THE WINDS QUITE A BIT OVER THE COASTAL WATERS. LOOKS TO BE A HIGH LIKELIHOOD OF NORTHEASTERLY STORM FORCE GUSTS...PARTICULARLY OVER THE EASTERN WATERS. DEPENDING ON THE EXACT TRACK OF THE LOW...COULD SEE STORM FORCE GUSTS AS FAR WEST AS THE WATERS SOUTH OF RHODE ISLAND. SUNDAY...RAIN MOVES OFF TO THE EAST. WINDS SHIFT NORTHWEST. EXPECTING THESE WINDS TO DIMINISH BELOW GALE FORCE SUNDAY NIGHT. WITH THE WIND SHIFT...ROUGH SEAS WILL TRANSITION FARTHER OFFSHORE WITH DIMINISHING SEAS CLOSER TO SHORE. GALE WARNINGS WILL LIKELY LINGER INTO THE EVENING HOURS. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...MODERATE CONFIDENCE. SUNDAY NIGHT AND MONDAY...GUSTY NORTHWEST WINDS AT GALE FORCE EARLY SUNDAY NIGHT. WINDS THEN DIMINISH BUT REMAIN 25 TO 30 KNOTS THROUGH MONDAY. SEAS DIMINSH SUNDAY NIGHT BUT LINGER 5 TO 10 FEET THROUGH MONDAY. TUESDAY...WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT LEVELS. WEDNESDAY...SEAS WILL REMAIN BELOW 5 FEET. SOUTHWEST WINDS WILL INCREASE WITH FREQUENT GUSTS 20 TO 25 KNOTS.
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&& .TIDES/COASTAL FLOODING... 1015 AM UPDATE...A COASTAL FLOOD WATCH WAS ISSUED FOR THE SATURDAY EVENING AND EARLY SUNDAY MORNING HIGH TIDE CYCLES FOR THE EASTERN MA COAST...INCLUDING THE NORTH FACING PORTION OF CAPE COD AND NANTUCKET. THIS IS FOR THE POTENTIAL OF MINOR TO ISOLATED POCKETS OF MODERATE COASTAL FLOODING POSSIBLE ALONG WITH BEACH EROSION. ASTRONOMICAL HIGH TIDES ARE RATHER LOW SATURDAY EVENING AND AGAIN EARLY SUNDAY MORNING. HOWEVER...STRONG NORTH TO NORTHEAST WIND GUSTS UP TO 50 KNOTS MAY RESULT IN SEAS BUILDING TO AROUND 20 FEET OVER THE OPEN WATERS. STILL SOME UNCERTAINTY AS TO HOW STRONG THE WINDS WILL GET...GIVEN MODEL SPREAD. HOWEVER...THERE CERTAINLY IS THE POTENTIAL FOR A 2 TO 2.5 STORM SURGE TO COMBINED WITH SIGNIFICANT WAVE ACTION. THIS WILL RESULT IN MINOR COASTAL FLOODING WITH PERHAPS ISOLATED POCKETS OF MODERATE COASTAL FLOODING. THEREFORE...WE FELT IT WAS WORTH AT LEAST A WATCH AT THIS TIME. THE HIGHEST RISK AREAS APPEAR TO BE HULL AND SCITUATE. WE ALSO HAVE TO BE CONCERNED WITH THE TYPICAL HOT SPOTS...SUCH AS SALISBURY AND PLUM ISLAND WHICH ARE VERY SUSCEPTIBLE TO BEACH EROSION. WILL ALSO HAVE TO KEEP AN EYE ON NANTUCKET HARBOR...AS STRONG NORTHERLY WINDS CAN CAUSE ISSUES FOR THEM. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...HIGH WIND WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY MORNING FOR MAZ005>007-013>021. COASTAL FLOOD WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR MAZ007-015-016-019-022-024. HIGH WIND WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR MAZ022>024. NH...NONE. RI...HIGH WIND WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY MORNING FOR RIZ001>008. MARINE...STORM WATCH FROM SATURDAY MORNING THROUGH SUNDAY AFTERNOON FOR ANZ230>237-250-251-254>256. && $$ SYNOPSIS...WTB/EVT NEAR TERM...BELK/RLG/EVT SHORT TERM...EVT LONG TERM...WTB AVIATION...WTB/RLG MARINE...WTB/EVT TIDES/COASTAL FLOODING...

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