Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 271740 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 140 PM EDT MON APR 27 2015 .SYNOPSIS... UNSETTLED WEATHER AND BELOW NORMAL TEMPS WILL CONTINUE INTO TUESDAY. WEAK HIGH PRESSURE WILL BRIEFLY VISIT THE AREA DURING MIDWEEK...WITH TEMPERATURES NEAR OR SLIGHTLY ABOVE NORMAL. BELOW NORMAL TEMPS AND UNSETTLED WEATHER RETURN THURSDAY NIGHT INTO FRIDAY...WITH IMPROVEMENTS FOR THIS WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 130 PM UPDATE... LINE OF SHOWERS MOVING SOUTHWARD TO WHICH THE HRRR HAS TRENDED WELL...PERHAPS AN HOUR OFF. PREVIOUS DISCUSSION BELOW APPLIES. PREVIOUS DISCUSSION... SOME LIGHT SHOWER ACTIVITY IS MOVING OFFSHORE ALONG AN ELONGATED TROUGH AND ATTENDANT STRETCHED MID-LEVEL ENERGY REARWARD OF THE NEARLY-STACKED LOW SE OF NEWFOUNDLAND SWEEP ACROSS S NEW ENGLAND. FOCUS SHIFTS TOWARDS A RAIN-BAND PUSHING S OUT OF MAINE ALONG A BACK-DOOR COLD FRONT. COLLOCATED WITH A STOUT MID-LEVEL IMPULSE ASSOCIATED WITH THE BACK-BUILDING LOW AHEAD OF WHICH DEEP-LAYER FORCING IS INVOKED HAVE HIGH CONFIDENCE IN HRRR TRENDS AS WE GO INTO EVENING. LIKELY TO HIGH CATEGORICAL POPS MAINLY E OF THE CT- RIVER VALLEY. PUNCH OF COLDER AIR S/SW AS WINDS TURN BLUSTERY OUT OF THE N/NE. MORE DETAILS IN THE /TONIGHT/ DISCUSSION BELOW. SO FOR TODAY...ABUNDANCE OF CLOUDS WITH SPOTTY SHOWERS WHICH WOULD YIELD SOME MEASURABLE PRECIPITATION ON THE ORDER OF A TRACE TO A COUPLE OF HUNDREDTHS. TEMPERATURES KEPT AT BELOW-SEASONABLE LEVELS AROUND THE MID- TO UPPER-50S...COOLER ACROSS THE HIGH TERRAIN AND ALONG THE COAST. SADLY NOT VERY SPRING-LIKE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... THE CORE OF THE UPPER LEVEL CUTOFF MAKES ITS CLOSET APPROACH TO S NEW ENGLAND THIS EVENING...THEN STARTS TO ROTATE BACK OUT TO SEA LATE TONIGHT INTO TUESDAY. AS IT DOES...SOUTHERN NEW ENGLAND GETS INTO A PATTERN OF DECREASING MOISTURE. IN TURN...THIS MEANS A LOWER RISK FOR RAINFALL THROUGH THE DAY TUESDAY. WINDS ARE EXPECTED TO BE NORTH TO NORTHWEST TONIGHT INTO TUESDAY. THERE IS STILL SOME QUESTION IF THE PRESSURE GRADIENT RELAXES ENOUGH...AND WE SEE ENOUGH SUNSHINE...WHERE SEABREEZES COULD DEVELOP. THAT WOULD HAVE A MAJOR IMPACT ON TEMPERATURES TOWARD THE COASTS. AT THIS TIME...THINKING THE PRESSURE GRADIENT STAYS STRONG ENOUGH TO PREVENT SEABREEZE DEVELOPMENT TUESDAY. THIS WILL NEED TO BE MONITORED. TEMPERATURES RISE SLIGHTLY TUESDAY WITH THE ADDITIONAL SUNSHINE... BUT SHOULD STILL BE SLIGHTLY LOWER THAN NORMAL FOR THIS TIME OF YEAR. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * RELIEF ON WEDNESDAY WITH ABOVE AVERAGE TEMPS * DIGGING TROUGH/COASTAL LOW ON THURS/FRIDAY BRINGS BELOW NORMAL TEMPS * IMPROVEMENTS FOR THE WEEKEND OVERVIEW... CLOSED LOW WHICH HAS PLAGUED THE REGION FOR SEVERAL DAYS NOW WILL EJECT OFFSHORE BY TUES ALLOWING FOR BRIEF RIDGING ON WED. STILL WATCHING TWO SYSTEMS WHICH WILL PUT THE NORTHEAST BACK INTO A DEEP TROUGH BY THURSDAY/FRIDAY. STILL A LOT OF UNCERTAINTY ON HOW THE NORTHERN STREAM PHASES WITH THE SOUTHERN STREAM WHICH HAS ALLOWED FOR LARGE MODEL SPREAD OVER THE PAST SEVERAL DAYS. OVERALL THE 00Z GUIDANCE GENERALLY SHOWS A STRONGER OH VLY/MID ATLC UPPER LOW THUS LEADING TO A FARTHER WESTWARD SURFACE TRACK THURSDAY. THE 00Z GFS IS LOOKING LIKE A DEEP EXTREME WITH ITS UPR LOW THOUGH...WITH THE GEFS MEAN AND NEW ECMWF SUPPORTING MORE MODERATE DEPTH. THEREFORE BELIEVE GFS TO BE AN OUTLIER COMPARED THE OTHER GUIDANCE AND TRENDED TOWARDS WPC/EC/UKMET. ONCE THE SYSTEMS PHASE...SURFACE LOW PRESSURE WILL DEVELOP OVER THE CAROLINAS AND MOVE UP THE EASTERN SEABOARD. APPEARS THAT THIS COASTAL LOW WILL STAY SOUTH AND EAST OF THE BENCHMARK...WHICH IS SUPPORTED BY THE 12Z EC ENSEMBLES. BEGINNING OF THE WEEKEND SHOULD BE IMPROVEMENTS AS CENTRAL CONUS RIDGE WILL MOVE EASTWARD. DETAILS... * WEDNESDAY...HIGH CONFIDENCE. DIGGING TROUGH ACROSS THE CENTRAL CONUS WILL PUSH A WEAK RIDGE OVER THE REGION. THIS WILL GIVE SOUTHERN NEW ENGLAND A BREAK IN PRECIP AND TEMPS ABOVE NORMAL. COASTAL COMMUNITIES WILL BE COOLER THANKS TO SEA BREEZE DEVELOPMENT. * THURSDAY AND FRIDAY...LOW CONFIDENCE. STILL SOME UNCERTAINTY IN THIS PORTION OF THE FORECAST. EVERYTHING IS DEPENDENT ON HOW THE LOW CURRENTLY LOCATED OVER THE 4 CORNERS AND THE DIGGING NORTHERN STREAM WAVES BEHAVES. REGARDLESS APPEARS DEEP TROUGH WILL DEVELOP PUTTING SOUTHERN NEW ENGLAND BACK BELOW NORMAL FOR TEMPS. THIS TROUGH WILL DEVELOP A COASTAL LOW OFF THE CAROLINAS AND PUSH NORTHWARDS. THE GFS APPEARS TO BE THE OUTLIER STALLING THE LOW INSIDE THE BENCHMARK FOR SEVERAL HOURS. TRENDED TOWARDS THE CONSISTENT EC WHICH STILL KEEPS IT SOUTH AND EAST OF THE BENCHMARK...YET SLIGHTLY STRONGER THEN PREV RUNS. BELIEVE THURS AND FRI WILL BE MORE HIT OF MISS SHOWERS AND CONTINUE TO KEEP HIGHER POPS ALONG THE CAPE AND ISLANDS FOR COASTAL SYSTEM. ALSO KNOCKED TEMPS DOWN A FEW DEGREES FROM GUIDANCE AS CLOUDS WILL LIMIT DIURNAL HEATING. * THE WEEKEND...MODERATE CONFIDENCE. UPPER LEVEL TROUGH WILL BEGIN TO MOVE OFFSHORE BY SATURDAY AS WEAK RIDGE BUILDS OVER NEW ENGLAND. MAY NEED TO WATCH QUICK MOVING NORTHERN STREAM ENERGY WHICH COULD GIVE SHOWERS TO THE AREA ON SUNDAY...BUT OVERALL HOPING FOR A NICE WEEKEND WITH TEMPS NEAR NORMAL. * MONDAY...LOW CONFIDENCE. MONDAY IS LOOKING WARM BUT STILL UNCERTAIN ON PRECIP CHANCES AS PATTERN WILL ALL BE DEPENDENT ON THE THURS/FRI SYSTEM. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT-TERM /TILL 0Z WEDNESDAY/... 18Z UPDATE... TODAY INTO TONIGHT...HIGH CONFIDENCE. LOW-END VFR CIGS MAINLY. MVFR CIGS/VSBYS WITH -SHRA...ACROSS E MA / RI...DEVELOPING TOWARDS LATER AFTERNOON INTO EVENING...CONCLUDING BY 6Z. LOW- RISK IFR FOR CAPE. NW-WINDS BACKING N-NE BECOMING BLUSTERY. TUESDAY...MODERATE CONFIDENCE. CIGS IMPROVE TO LOW-END VFR. SEA BREEZE DEVELOPMENT IS POSSIBLE ALONG THE EAST COAST. REMAINS BLUSTERY OUT N TURNING NW. KBOS TAF...HIGH CONFIDENCE IN TAF. LOW CONFIDENCE ON SEABREEZE THIS AFTERNOON. WINDS BACK NE TOWARDS EVENING WITH BETTER SHRA CHANCES. KBDL TAF...HIGH CONFIDENCE IN TAF. .OUTLOOK /WEDNESDAY THROUGH FRIDAY/... WEDNESDAY...MODERATE CONFIDENCE. VFR CONDITIONS. SEA BREEZE DEVELOPMENT POSSIBLE. THURSDAY INTO FRIDAY...LOW CONFIDENCE. VFR CONDITIONS WITH MVFR POSSIBLE IN SCT SHOWERS ACROSS THE EASTERN HALF COASTLINE. CIGS/VSBYS COULD BE LOWER DEPENDENT ON THE TRACK OF A LOW PRESSURE SYSTEM. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT-TERM /TILL TUESDAY EVENING/... 130 PM UPDATE... GUSTY WINDS ACROSS THE INTERIOR...BUT A WEAK SEA-BREEZE BOUNDARY REMAINS ALONG THE COAST LENDING TO SOME VARIANCE IN THE WIND AT TIMES. NEVERTHELESS THE DOMINANT FLOW WILL BE NW WITH GUSTS UP TO 20 KTS. SEAS LIKELY TO ENHANCE...ESPECIALLY TOWARDS EVENING AS A COLD FRONTAL BOUNDARY DROPS S ALONG WHICH SHOWERS ARE EXPECTED. WITH PASSAGE...WIND GUSTS INCREASE OUT OF THE N WITH THE POTENTIAL FOR GALES. THESE WINDS CONTINUE INTO MORNING DIMINISHING THROUGH TUESDAY. SMALL-CRAFTS CONTINUE...BUT MAY NEED TO EXPAND AND ARE EVALUATING THE POSSIBILITY OF GALES. WAVES BUILDING 6-8 FEET ON THE E-OUTER WATERS. .OUTLOOK /TUESDAY NIGHT THROUGH WEDNESDAY/...HIGH CONFIDENCE. THURSDAY AND FRIDAY...MODERATE CONFIDENCE. WEDNESDAY...GOOD BOATING WEATHER AS WIND AND SEAS WILL BE BELOW SCA. THURSDAY AND FRIDAY...A LOW PRESSURE SYSTEM EMERGES FROM THE CAROLINA COASTLINE AND IS EXPECTED TO TRACK NORTHEASTWARD. THERE IS CONSIDERABLE UNCERTAINTY IN HOW CLOSE THE CENTER OF THIS SYSTEM MAKES IT TO THE SOUTHERN NEW ENGLAND COASTLINE. IF IT STAYS WELL OFFSHORE...SWELLS COULD BRING A PERIOD OF ROUGH SEAS TO OUR COASTAL WATERS. A CLOSER APPROACH WOULD HAVE SIGNIFICANT MARINE IMPACTS FOR FRIDAY. AGAIN HAVE UNDERCUT WNA WAVE GUIDANCE BY 40 TO 50 PERCENT. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 2 PM EDT TUESDAY FOR ANZ232. SMALL CRAFT ADVISORY FROM 6 AM TO 10 AM EDT TUESDAY FOR ANZ230. SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 2 PM EDT TUESDAY FOR ANZ231. SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM EDT TUESDAY FOR ANZ250-254-255. SMALL CRAFT ADVISORY FROM 4 AM TO 6 PM EDT TUESDAY FOR ANZ251. && $$ SYNOPSIS...BELK/DUNTEN NEAR TERM...BELK/DUNTEN/SIPPRELL SHORT TERM...BELK LONG TERM...DUNTEN AVIATION...BELK/DUNTEN/SIPPRELL MARINE...BELK/DUNTEN

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