Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 162303 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 703 PM EDT THU OCT 16 2014 .SYNOPSIS...
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SCATTERED SHOWERS WILL IMPACT EASTERN MASSACHUSETTS THIS EVENING WITH PERIODS OF HEAVY RAIN CONFINED TO CAPE COD AND NANTUCKET. PLEASANT WEATHER IS EXPECTED FRIDAY INTO SATURDAY...WITH MILD TEMPERATURES CONTINUING. A COLD FRONT WILL SWEEP ACROSS THE REGION SATURDAY EVENING WITH MUCH COOLER TEMPERATURES BY SUNDAY. HIGH PRESSURE BUILDS IN EARLY NEXT WEEK. COASTAL LOW WILL DEVELOP TUES- THURSDAY...A LOT OF UNCERTAINTY ON ITS IMPACT TO SOUTHERN NEW ENGLAND SO STAY TUNED.
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&& .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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***FLASH FLOOD WATCH CONFINED TO CAPE COD AND NANTUCKET UNTIL 11 PM *** 7 PM UPDATE... AXIS OF HEAVY RAIN JUST CLIPPING NANTUCKET AND CAPE COD AT 7 PM WITH LIGHTER SHOWERS OVER RI AND EASTERN MA. THUS WILL DROP THE FLOOD WATCH FOR THESE AREAS. HOWEVER WILL CONTINUE THE FLOOD WATCH FOR CAPE COD AND EXPAND IT TO INCLUDE NANTUCKET AS SOME OF THE MODEL GUIDANCE SUGGEST NEGATIVE TILTED TROUGH MAY BE ABLE TO RETROGRADE WARM CONVEYOR BELT MOISTURE PLUME BACK INTO THIS AREA LATER THIS EVENING. CONCERN IS THAT COOLING CLOUD TOPS WELL SOUTH OF NANTUCKET MAY CLIP THE ISLAND AND CAPE COD LATER THIS EVENING. GIVEN THE TROPICAL CONNECTION...NW TO SE MID LEVEL TROUGH ORIENTATION ALONG WITH VERY STRONG UPPER LEVEL JET STREAK THINK THERE IS A LOW RISK OF HEAVY RAINS AND POTENTIAL FLOODING LATER THIS EVENING ACROSS NANTUCKET AND CAPE COD. WATCH IS VALID TIL 11 PM BUT MAY HAVE TO EXTEND THIS TIL 2 AM OR SO. WILL MONITOR CLOSELY. OTHERWISE WITH DEEP MOISTURE PLUME CONFINED TO CAPE COD AND NANTUCKET...LIGHTER NUISANCE TYPE SHOWERS ARE POSSIBLE ACROSS RI AND EASTERN MA. MEANWHILE...CLEARING LINE IS BACK ACROSS THE BERKSHIRES OF WESTERN MA...CENTRAL CT TO BLOCK ISLAND. THIS WILL LIKELY FILL BACK IN OVERNIGHT AS MID/UPPER TROUGH SWINGS ACROSS THE AREA. MILD BUT NOT AS WARM OR HUMID AS LAST NIGHT AS DEW PTS IN THE 50S ADVECT ACROSS THE REGION OVERNIGHT. HOWEVER GIVEN THE HEAVY RAINFALL FROM TODAY AND SLACKENING WINDS EXPECT PATCHY DENSE FOG OVERNIGHT.
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&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... FRIDAY... A BEAUTIFUL DAY OF WEATHER ON TAP TO CLOSE OUT THE WORK WEEK. ANY LOW CLOUDS/FOG PATCHES SHOULD BURN OFF BY MID TO LATE MORNING. PARTLY TO MOSTLY SUNNY SKIES EXPECTED WITH SOUTHWEST FLOW ALOFT CONTINUING. THEREFORE...TEMPS WILL REMAIN MILD FOR THIS TIME OF YEAR. HIGHS SHOULD RANGE FROM THE UPPER 60S ACROSS THE HIGHER TERRAIN...TO THE LOWER 70S ELSEWHERE. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... HEADLINES... *SCATTERED SHOWERS POSSIBLE DURING THE WEEKEND *MONDAY HAS BEST CHANCE TO REMAIN DRY...BUT WILL BE CLOUDY *COASTAL STORM DEVELOPS TUES AND STAYS THROUGH THURS OVERVIEW... AN AMPLIFIED PATTERN OVER THE UNITED STATES BRINGS A RIDGE OVER THE WESTERN STATES AND A TROUGH OVER THE EASTERN STATES. AN UPPER LEVEL LOW OVER THE EASTERN UNITED STATES SERVES AS THE POINT THAT SHORTWAVES ARE ABLE TO PINWHEEL AROUND FOR THE WEEKEND. AS THE UPPER LEVEL LOW SLOWLY LEAVES THE STATES ANOTHER SHORTWAVE DIVES OUT OF CANADA AND DEVELOPS INTO A COASTAL LOW INSIDE THE TEMPERATURE GRADIENT ALONG THE EAST COAST. THIS SETS UP ANOTHER PERIOD OF WEAK SHOWERS WHERE MODEL DISCREPANCIES AGAIN RESULT. MODELS HAVE A HARD TIME HANDLING THE WEEKEND/S AND LATE WEEK/S PRECIPITATION FROM THE UPPER LEVEL LOWS/ SLOW MOVEMENT. AS IS FREQUENTLY SEEN IN MODEL EVOLUTION...VORTICITY IS NOT HANDLED WELL FAR INTO THE FUTURE. SO EXACT PLACEMENT OF THE PRECIPITATION FOR NEXT WEEK/S COASTAL LOW HAS LOW CONFIDENCE ASSOCIATED WITH IT. DAILIES... SATURDAY...AN UPPER LEVEL AND IT/S ASSOCIATED SHORTWAVE OVER THE NORTHERN MIDWEST MOVES EAST AND THEN PINWHEELS AROUND THE UPPER LEVEL LOW OVER THE NORTHEAST. WITH THE COLD AIR ALOFT...AN APPROACHING COLD FRONT AND THE AFOREMENTIONED SHORTWAVE...SHOWERS SHOULD RESULT ESPECIALLY LATER IN THE DAY. THEY LOOK TO BE ON THE WEAKER END OF THE SPECTRUM AND SCATTERED AT BEST. SOME SMALL HAIL COULD BE SEEN WITH THE COLDER AIR ALOFT AND THE FREEZING LEVEL CLOSER TO THE SURFACE THAN NORMAL. SUNNY PEAKS SHOULD BE SEEN DURING THIS PERIOD. WITH 850MB TEMPS AROUND 9C...COULD SEE SFC TEMPS IN THE LOW 70S DURING THE DAY AHEAD OF THE FRONT. WITH MIXING TO 850MB WIND GUSTS COULD GET TO 25 MPH. SUNDAY...SMALL CHANCE OF SHOWERS IN THE MORNING. AFTER THE COLD FRONT...COOLER AIR IS ABLE TO SPILL IN. CLOUDS THIN OUT TOWARDS MID AFTERNOON AND DRYING OCCURS. WITH 850 TEMPS AROUND -4C...SFC TEMPS SHOULD STAY IN THE LOW TO MID 50S. THAT/S AROUND A 20F TEMP SWING IN TERMS OF HIGH TEMPS THANKS TO THE COLD FRONT. WITH MIXING TO 850MB WIND GUSTS COULD GET TO 30 MPH. MONDAY...RIDGING OCCURS AS A HIGH PRESSURE SYSTEM SCOOTS SOUTH OF THE REGION. THIS KEEPS THE REGION DRY. TEMPS COULD GET INTO THE MID 50S WITH LESS OF A NORTHERLY FLOW. TUESDAY THROUGH THURSDAY...THIS PERIOD INCLUDES QUITE A BIT OF UNCERTAINTY. ENSEMBLES ARE SMOOTHING OVER A LOT OF UNCERTAINTY ESPECIALLY IN TERMS OF SURFACE PRESSURE AND TIMING. THE GENERAL PATTERN FOR THIS TIME PERIOD EVOLVES AS ANOTHER SHORTWAVE DIVES SOUTH OUT OF CANADA. IT THEN PINWHEELS AROUND THE BOTTOM OF THE TROUGH FORMED BY THE UPPER LEVEL LOW. AS THE UPPER LEVEL CENTERED IN SOUTHEAST CANADA QUICKLY MOVES NORTHEAST TO GO OFFSHORE...A SPACE OPENS UP FOR DEVELOPMENT ALONG THE EAST COAST. THE QUESTION THEN BECOMES IF THE SHORTWAVE CAN DEVELOP INTO AN UPPER LEVEL LOW. THE ECENS HAS IT DOING JUST THAT...BUT THE GEFS HAS MORE SPREAD WITH A POSITIVE TILT IN THE HEIGHTS. NORTHEAST FLOW DOES OCCUR IN ENSEMBLES ESPECIALLY LATER TUESDAY AS THE COASTAL LOW IS SOUTH OF THE REGION. AS IT PULLS TO THE EAST...NORTHWEST FLOW COMES IN LATE THURSDAY. RAIN LOOKS LIGHT...BUT STEADY OVER THIS PERIOD ESPECIALLY FROM LATER TUESDAY THROUGH MOST OF THURSDAY. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/...
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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 FRIDAY/...MODERATE CONFIDENCE TONIGHT AND HIGH CONFIDENCE ON FRIDAY. 7 PM UPDATE... NO WHOLESALE CHANGES FROM 18Z TAFS. IMPROVING TRENDS CONTINUE WITH HEAVY RAIN CONFINED TO CAPE COD AND NANTUCKET. THUNDERSTORMS WELL SOUTH OF NEW ENGLAND MAY CLIP NANTUCKET AND CAPE COD THRU AT LEAST 03Z AND POSSIBLY 06Z BEFORE MOVING WELL OFFSHORE. EARLIER DISCUSSION BELOW. =================================================================== TONIGHT...MVFR CONDITIONS DOMINATE THIS EVENING WITH PERIODS OF IFR CONDITIONS ALONG EASTERN NEW ENGLAND WHERE THE HEAVY RAIN WILL BE FOCUSED. LOW PROBABILITY OF AN ISOLATED THUNDERSTORM THROUGH 00Z. CONDITIONS IMPROVE EVEN IN THE EAST AFTER 00Z...BUT SCATTERED SHOWERS MAY PERSIST. ACROSS THE INTERIOR...TEMPORARY IMPROVEMENT TO VFR IS POSSIBLE BUT LOW CLOUDS AND PATCHY FOG MAY RE-DEVELOP. KBOS...MODERATE TO HIGH CONFIDENCE IN MVFR WITH PERIODS OF IFR CONDITIONS THROUGH 00Z. MAINLY MVFR TO PERHAPS EVEN VFR AFTER 00Z. KBDL...MODERATE CONFIDENCE. MVFR CONDITIONS THIS EVENING. MAY SEE IMPROVEMENT TO VFR FOR A TIME THIS EVENING...BUT WILL HAVE TO WATCH FOR LOWER CLOUDS AND PATCHY FOG MOVING INTO THE REGION OVERNIGHT. OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY... SATURDAY AND SUNDAY...MODERATE CONFIDENCE. VFR FOR MOST LOCATIONS. ISOLATED MVFR IN DIURNAL SHOWERS FOR BOTH DAYS. GUSTY WESTERLY WINDS UP TO 20 KTS...25 KTS ON SUNDAY. MONDAY...MODERATE CONFIDENCE. VFR. TUESDAY...MODERATE CONFIDENCE...RAIN OVERSPREADS THE REGION ESPECIALLY LATE IN THE DAY. WINDS TURN NE DURING THE DAY AS THE COASTAL STORM DEVELOPS.
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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 /TONIGHT THROUGH FRIDAY/...HIGH CONFIDENCE. 7 PM UPDATE... STRONGEST SSE WINDS HAVE MOVED EAST OF NANTUCKET AND CAPE COD AS OF 7 PM. HOWEVER LARGE SOUTHERLY WIND WAVES CONTINUE ON THE SOUTHERN OCEAN WATERS WITH SEAS OF 5 TO 9 FT. SWELLS FROM HURRICANE GONZALO STILL WELL SOUTH OF NEW ENGLAND. HEAVY RAIN AND THUNDERSTORMS TONIGHT SHOULD BE CONFINED TO NANTUCKET...CAPE COD AND POINTS EASTWARD...THEN WELL OFFSHORE AFTER 2 AM OR SO. EARLIER DISCUSSION BELOW. ==================================================================== TONIGHT...LOW LEVEL JET WILL CONTINUE TO RESULT IN SOUTHERLY WIND GUSTS OF 20 TO 25 KNOTS INTO THE EVENING OVER THE OPEN WATERS. WINDS SHOULD DIMINISH SOME BY LATE EVENING AS LOW LEVEL JET WEAKENS AND SHIFTS EAST OF THE REGION...BUT SCA SEAS WILL CONTINUE. HEAVY SHOWERS AND AN EMBEDDED THUNDERSTORM OR TWO WILL LOWER VISIBILITIES AT TIMES. FRIDAY...SOUTHWEST WIND GUSTS OF 20 TO 25 KNOTS ARE EXPECTED WITH GOOD MIXING BEHIND THE FRONT PARTICULARLY NEAR SHORE. HOWEVER...SEAS OF 5 TO 8 FEET EXPECTED ACROSS THE OPEN WATERS AS A RESULT OF SOUTHEAST SWELL FROM DISTANT HURRICANE GONZALO. SCA HEADLINES CONTINUE FOR MOST OPEN WATERS. OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY... SATURDAY...MODERATE CONFIDENCE...AS GONZALO PASSES SOUTHEAST OF THE REGION...EXPECT SEA SWELLS TO GO ABOVE SCA THRESHOLD AND WINDS TO GO ABOVE SCA THRESHOLD. SCA WILL BE NEEDED. SUNDAY...MODERATE CONFIDENCE. GUSTY WEST WINDS AROUND 30KTS WILL IMPACT THE WATERS AS WELL. STILL EXPECTING ROUGH SEAS AS CAA COMES IN AND INTERACTS WITH THE LEFTOVER SOUTHEAST SEA SWELLS FROM GONZALO. SCA WILL STILL PROBABLY NEEDED FOR THIS PERIOD. MONDAY...MODERATE CONFIDENCE. HIGH PRESSURE WILL SLIDE SOUTH OF THE WATERS REDUCING WIND SPEEDS TO 20 KT GUSTS. SEAS WILL REMAIN UP TO AROUND 5 FT ACROSS THE OUTER WATERS. TUESDAY...WINDS AND SEAS REMAIN BELOW SCA THRESHOLD. WIND GUSTS APPROACH 25 KTS AND SWELLS BEGIN TO RISE AS THE COASTAL STORM DEVELOPS LATE
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR MAZ022-024. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ231>234. SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ235-237- 254>256. SMALL CRAFT ADVISORY UNTIL 8 AM EDT SATURDAY FOR ANZ250.
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&& $$ SYNOPSIS...FRANK/99 NEAR TERM...FRANK/NOCERA SHORT TERM...FRANK LONG TERM...FRANK/99 AVIATION...FRANK/NOCERA/99 MARINE...FRANK/NOCERA/99

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