Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 311416 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1016 AM 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 U.S. FOR EARLY NEXT WEEK. ONE OR TWO COLD FRONTS MAY CROSS SOUTHERN NEW ENGLAND WEDNESDAY AND THURSDAY.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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***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.
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&& .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 THURSDAY/... BIG PICTURE... DEEP AMPLITUDE TROUGHS ON BOTH COASTS SATURDAY WITH A RIDGE IN BETWEEN. SHORTWAVE MOVING THROUGH THE EASTERN TROUGH GENERATES A CUTOFF UPPER LOW WITH TWO JET STREAMS...A NORTHERN STREAM ALONG THE CANADIAN BORDER AND A SOUTHERN STREAM MOVING WITH THE SHORT WAVE. THE PATTERN SHIFTS EAST DURING THE WEEK WITH THE RIDGE BUILDING OVER NEW ENGLAND. THE PATTERN THEN TRANSFORMS TO A MORE ZONAL FLOW. REMAINS OF THE PACIFIC COAST TROUGH MOVE ACROSS NEW ENGLAND MIDWEEK. COLDER THAN NORMAL HEIGHTS WITH THE EASTERN TROUGH THIS WEEKEND. HEIGHTS INCREASE TO NORMAL OR A LITTLE ABOVE NORMAL BY MIDWEEK. THIS POINTS TO A COLDER THAN NORMAL WEEKEND...TRENDING TO NORMAL TEMPERATURES BY MIDWEEK. 31/00Z GUIDANCE SUITE REMAINS IN DECENT OVERALL AGREEMENT. THERE ALSO REMAIN SOME DIFFERENCES WITH TRACK...INTENSITY AND TIMING. AT THIS POINT IT APPEARS SNOWFALL IS MOSTLY OFF THE TABLE AWAY FROM A VERY BRIEF PERIOD LATE SATURDAY NIGHT ACROSS THE HIGHER TERRAIN. EVEN THEN...IT WILL NOT AMOUNT TO MUCH. FAVORED A BLEND TO SMOOTH OVER SOME OF THE MORE MINOR DIFFERENCES. THIS RESULTED IN VERY GOOD CONTINUITY WITH THE PREVIOUS FORECAST. THE DAILIES... SATURDAY-SUNDAY... COASTAL STORM CONTINUES TO BE INDICATED FOR SATURDAY AND EARLY SUNDAY. SUPPORT COMES FROM TWO SETS OF FORCING MECHANISMS... SUGGESTING A TWO-PART EVENT. INITIAL FORCING COMES FROM RIGHT ENTRANCE REGION OF NORTHERN STREAM JET SATURDAY MORNING. THIS WILL SEND A COASTAL WAVE OF LOW PRESSURE PAST SOUTHERN NEW ENGLAND DURING THE DAY SATURDAY. THE SECOND FORCING COMES FROM LEFT EXIT REGION OF JET SUPPORTING A POTENT SHORTWAVE ROUNDING THE BASE OF THE EASTERN TROUGH LATE SATURDAY/SATURDAY NIGHT. EVEN SO...MOST OF THE FRONTOGENETIC FORCING WITH EACH SEGMENT IS FOCUSED OFFSHORE INTO THE MARITIMES AND MAINE. THE WESTERN EDGE OF THIS FORCING SHOULD EXTEND INTO SOUTHERN NEW ENGLAND WITH THE FIRST...AND POSSIBLY THE SECOND...OF THE SEGMENTS. WE EXPECT RAIN SATURDAY AND SATURDAY NIGHT WITH HIGHEST POPS OVER CAPE COD AND THE ISLANDS...LESSER VALUES NORTH AND WEST. STRONG PRESSURE GRADIENT AT THE SURFACE AND A 50 KNOT LOW LEVEL JET WILL CONTRIBUTE TO WINDY CONDITIONS. THE STRONGEST WINDS WILL BE OVER THE EASTERN/SOUTHEAST WATERS. STRONGEST LAND WINDS WILL BE OVER THE OUTER CAPE AND ISLANDS...DIMINISHING FARTHER WEST. HAVE FEATURED 45 KNOTS FOR THE STRONGEST WINDS AND 20-25 KNOTS IN THE INTERIOR. A COASTAL STORM WILL PASS US IN PIECES SATURDAY AND LATER SATURDAY NIGHT...AS NOTED ABOVE. EXPECT PRECIPITATION TO DIMINISH WEST TO EAST AFTER MIDNIGHT AND END ON THE MA EAST COAST AFTER SUNRISE SUNDAY MORNING. TEMPERATURES THROUGH MOST OF THIS STORM SHOULD REMAIN FAVORABLE FOR ALL RAIN. AS THE WINDS SHIFT FROM NORTHEAST TO NORTHWEST SATURDAY NIGHT...COLDER AIR WILL BE DRAWN IN WHICH COULD CHANGE THE LAST SHOWERS OVER TO SNOW ACROSS THE HIGHER TERRAIN. ANY ACCUMULATIONS SHOULD NOT BE MUCH MORE THAN A TRACE...WHERE IT SNOWS AT ALL. DRIER AIR SUNDAY WILL BRING CLEARING SKIES. COLD ADVECTION WILL PROMOTE MIXING THROUGH AT LEAST 850 MB. WINDS IN THIS LAYER WILL BE 35 TO 40 KNOTS...SO EXPECT NORTHWEST GUSTS TO AT LEAST THE LOWER END OF THIS RANGE. WINDS DIMINISH SUNDAY NIGHT AS THE STORM MOVES FARTHER AWAY. MONDAY-TUESDAY... HIGH PRESSURE BUILDS OVER THE REGION. MONDAY SHOULD BE SUNNY AS THIS HIGH MOVES OVERHEAD. MIXING WILL AGAIN BRING INCREASED WIND GUSTS DURING THE AFTERNOON. WINDS IN THE MIXED LAYER ARE EXPECTED AROUND 30 KNOTS WITH POTENTIAL FOR A LITTLE STRONGER SPEEDS. WINDS WILL DIMINISH WITH SUNSET. THIS HIGH PRESSURE MOVES OFFSHORE TUESDAY. THIS WILL MAKE ROOM FOR A WARM FRONT TO SWING PAST. SUFFICIENT LIFT AND MOISTURE TO SUPPORT MID AND HIGH CLOUDS...BUT THE BEST WARM FRONTAL LIFT WILL REMAIN TO OUR NORTH AND WEST SO EXPECT AT LEAST SOME SUN THROUGH THE DAY. WEDNESDAY-THURSDAY... LOW CONFIDENCE ON MIDWEEK WEATHER. AT LEAST ONE TROUGH IN THE ZONAL FLOW WILL SWING ACROSS THE REGION DURING THIS TIME. GFS AND ECMWF ARE HINTING AT ONE ON WEDNESDAY...BUT SHOWING A MORE SUBSTANTIAL TROUGH PASSING ON THURSDAY. THE FORECAST WILL HAVE CLOUDS AND LOW-END CHANCE OR SLIGHT CHANCE POPS. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/... TODAY...HIGH CONFIDENCE. VFR. ANY LEFTOVER IFR CIGS IN PATCHY FOG WILL IMPROVE BY 13Z. TONIGHT...MODERATE CONFIDENCE. CONDITIONS DETERIORATE THROUGH THE NIGHT TO MVFR-IFR FROM SOUTH TO NORTH WITH LOWEST CONDITIONS ALONG THE COAST. EXPECT LIGHT RAIN ALONG THE S COAST AND INTO SE MA AROUND OR AFTER MIDNIGHT...MOVING INTO THE REMAINDER MOST OF THE REGION TOWARD DAYBREAK. KBOS...HIGH CONFIDENCE IN TAF. KBDL...HIGH CONFIDENCE IN TAF. OUTLOOK...SATURDAY THROUGH TUESDAY...MODERATE CONFIDENCE. SATURDAY-SUNDAY...IFR CIGS AND MVFR OR IFR VSBYS IN PERIODS OF RAIN SATURDAY AND SATURDAY NIGHT. VFR AND DRIER WEATHER MOVE IN FROM WEST TO EAST EARLY SUNDAY. NORTHEAST WINDS SATURDAY GUSTING 35-45 KNOTS ON THE CAPE AND ISLANDS AND 25-35 KNOTS ACROSS THE COASTAL PLAIN. WINDS SHIFT TO NORTH SATURDAY NIGHT AND NORTHWEST SUNDAY. GUSTS 40- 45 KNOTS ON THE CAPE AND ISLANDS...WITH 25-35 KNOTS ELSEWHERE ACROSS SOUTHERN NEW ENGLAND. MONDAY...VFR. DAYTIME WIND GUSTS WILL INCREASE TO NEAR 30 KNOTS INLAND AND 35 KNOTS CAPE AND ISLANDS...DIMINISHING TOWARD EVENING. TUESDAY...VFR WITH INCREASING HIGH CLOUDS. && .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. OUTLOOK...SATURDAY THROUGH TUESDAY...MODERATE CONFIDENCE. ***STORM WATCH ISSUED FOR ALL THE COASTAL WATERS FOR SATURDAY AFTERNOON THROUGH SUNDAY MORNING*** 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. MONDAY...GUSTY NORTHWEST WINDS WITH WIND GUSTS APPROACHING GALE FORCE AGAIN DURING THE DAY. WINDS DIMINISH TOWARD EVENING. SEAS WILL LINGER AT 5-9 FEET...ESPECIALLY ON THE OUTER WATERS. SMALL CRAFT ADVISORY IS LIKELY...LOW END CHANCE THAT GALES MAY BE NEEDED ON SOME OF THE WATERS. TUESDAY...WINDS AND SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY LEVELS.
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&& .TIDES/COASTAL FLOODING...
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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.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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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.
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&& $$ SYNOPSIS...WTB/EVT NEAR TERM...BELK/RLG/EVT SHORT TERM...EVT LONG TERM...WTB AVIATION...WTB/EVT MARINE...WTB/EVT TIDES/COASTAL FLOODING...FRANK

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