Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 040804 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 404 AM EDT TUE AUG 4 2015 .SYNOPSIS...
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THUNDERSTORMS ARE ONCE AGAIN EXPECTED TODAY...BUT MAINLY ACROSS THE EASTERN HALF OF THE AREA. SOME OF THESE MAY BECOME SEVERE. DRY...WARM AND LESS HUMID WEATHER ARRIVES THURSDAY. A PERIOD OF UNSETTLED WEATHER IS POSSIBLE THURSDAY NIGHT INTO SATURDAY BUT CONFIDENCE IS LOW ON THE TIMING OF POTENTIAL WET WEATHER.
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&& .NEAR TERM /THROUGH WEDNESDAY/...
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CONVECTION DEVELOPING IN PA AND SE NY CONTINUES TO DIMINISH AS IT APPROACHES THE NE...WHERE DRY AIR AND SOME SUBSIDENCE CONTINUES TO LIMIT THE CONVECTION AS IT APPROACHES. ONLY SOME SHOWERS JUST NOW ENTERING THE LOWER CT VALLEY. STRONGER STORMS ARE STAYING TO THE S...MAINLY WHERE THE HIGHEST CAPE VALUES ARE PER LATEST MESO- ANALYSIS. THEREFORE...OUTSIDE OF A SHOWER...OR MAINLY AN ISOLATED RUMBLE OF THUNDER IN THE W SUSPECT MOST OF THE MORNING TO REMAIN QUIET. THE REST OF THE DAY...STILL REMAINS SOMEWHAT UNCERTAIN. AT ODDS IS THE ABILITY TO GENERATE SFC INSTABILITY AS A COLD FRONT SWEEPS THROUGH FROM ABOUT 14Z - 22Z. UPPER LVL INSTABILITY IS LIKELY SOMEWHERE BETWEEN THE MOIST NAM AND THE DRIER GFS...BUT WITH A MODIFIED EML AND 6.0-7.0C/KM LAPSE RATES AND AROUND 2000J/KG OF MU CAPE...THERE IS PLENTY AVAILABLE. SHEAR INCREASES AS THE FRONT APPROACHES AS WELL. SREF PROBS CONTINUE TO HIGHLIGHT GREATER THAN 50 PERCENT PROBABILITY OF MUCAPES GREATER THANK 2000/SHEAR GREATER THAN 40 KT...ESPECIALLY ACROSS THE ERN 2/3 OF THE REGION...WHERE SPC HAS UPGRADED TO A SLIGHT RISK. THE SFC CONNECTION...WILL BE BASED ON THE AMOUNT OF CLOUD COVER THAT REMAINS OVER THE AREA FROM THE WEAKENED CONVECTION THIS MORNING AND LOW STRATUS ACROSS SE MASS. LATEST QPF ON MESOSCALE GUIDANCE IS HIGHER THAN PREVIOUS RUNS...WHICH INCREASES CONFIDENCE THAT BETTER DESTABILIZATION WILL OCCUR LATER IN THE DAY IN SPITE OF THE EARLY CLOUD COVER...THEREFORE...WILL INCREASE AFTERNOON/EVENING POPS...AND BE ADDING ENHANCED/SEVERE WORDING WITH THIS UPDATE. SOME DRY AIR AT THE SFC...AND SHEAR SUGGEST THAT STRONG WINDS AND DOWNDRAFTS ARE THE PRIMARY CONCERN. SOME HAIL POSSIBLE ESPECIALLY GIVEN NAM SHOWS HAIL CAPES APPROACHING 500+. PWATS INCREASING TO NEAR 2.0 INCHES WILL ONCE AGAIN SUPPORT HEAVY RAIN...BUT STORMS SHOULD BE MOVING. SHEAR ALSO HIGH ENOUGH TO SUPPORT THE RISK OF A WEAK TORNADO...REFLECTING CURRENT THINKING BY SPC. THEREFORE...STAY TUNED TO UPDATES THROUGH THE DAY. OTHERWISE...HEAT AND HUMIDITY REMAINS TODAY AHEAD OF THE FRONT...WITH DWPTS IN THE UPPER 6OS TO NEAR 70. HIGHS MAINLY IN THE MID-UPPER 80S.
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&& .SHORT TERM /WEDNESDAY NIGHT THROUGH 6 PM WEDNESDAY/...
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OVERNIGHT... COLD FRONT WILL BE SLOWING TO A NEAR STALL BETWEEN 00Z AND 04Z THIS EVENING JUST OFFSHORE. THIS WILL ALLOW A CONTINUATION OF T-STORM RISK MAINLY ACROSS COASTAL REGIONS UNTIL DRIER AIR MOVES IN FROM THE NW AND CONVECTION SHIFTS S TOWARD BETTER INSTABILITY. THEREFORE...GRADUAL IMPROVEMENT EXPECTED. SOME FOG POSSIBLE WHERE RAINFALL OCCURS. OTHERWISE...TEMPS A LITTLE COOLER...MAINLY IN THE LOWER 60S ACROSS THE AREA...OR EVEN IN THE 50S ACROSS NW MA. WEDNESDAY... CYCLONICALLY CURVED FLOW REMAINS IN PLACE ACROSS THE REGION COMBINED WITH H5 TEMPS ABNORMALLY COLD...AROUND -13C. STALLED FRONTAL BOUNDARY REMAINS TO THE S...BUT ONE FINAL SHORTWAVE WILL BE ROTATING THROUGH TO THE N. THIS MAY LEAD TO SOME SCT SHOWERS/T-STORMS MAINLY N OF THE MASS PIKE. WITH THE VERY COLD H5 TEMPERATURES...THERE IS A RISK FOR HAIL AS WELL. KEY WILL BE HOW MUCH DRY AIR BUILDS THROUGH THE COLUMN. NOT EXPECTING SHOWERS/STORMS TO BE AS WIDESPREAD AS TODAY...BUT SOME LOW CHANCE OR AT LEAST SLIGHT CHANCE POPS ARE NEEDED TO REFLECT THE RISK. WARMER TEMPS REMAIN IN PLACE...MAINLY THE LOW-MID 80S.
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&& .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... HIGHLIGHTS... * UNSETTLED WEATHER POSSIBLE AROUND FRIDAY * TEMPERATURES TRENDING BELOW NORMAL DURING THIS PERIOD OVERALL...THE MODELS HAVE RATHER POOR AGREEMENT ON THE GENERAL PATTERN AND TIMING THROUGH THE LONG TERM. IN SOME TIME PERIODS IT SEEMS THAT THE GFS MAY JUST BE SLOWER THAN THE ECMWF. IN OTHERS... THEY ARE JUST COMPLETELY DIFFERENT. THE ENSEMBLES ARE NOT MUCH HELP IN THAT THE ECMWF ENSEMBLES LOOK VERY SIMILAR TO THE OPERATIONAL MODEL AND THE GEFS IS VERY SIMILAR TO THE GFS. BASICALLY HAVE TWO FAIRLY DIFFERENT SOLUTIONS FOR MUCH OF THE LONG TERM. HOWEVER... GENERAL TRENDS ARE SIMILAR. LOOKING AT A PERIOD OF UNSETTLED WEATHER WITH TEMPERATURES TRENDING BELOW NORMAL THROUGH MUCH OF THE WEEK. WEDNESDAY...LOOKS TO BE THE WARMEST DAY OF THE PERIOD WITH TEMPERATURES AROUND OR JUST ABOVE NORMAL. DESPITE THE POTENTIAL FOR A FEW SHOWERS OR THUNDERSTORMS ACROSS THE NORTHWESTERN ZONES AS A SHORTWAVE PUSHES INTO THE REGION...EXPECT MUCH OF THE DAY AND MUCH OF THE AREA TO REMAIN DRY. THURSDAY...MUCH OF THE DAY LOOKS TO BE DRY WITH HIGH PRESSURE BUILDING INTO THE AREA. THIS IS ONE OF THOSE TIMES THE TIMING IS OFF BETWEEN THE ECMWF AND THE GFS. THE ECMWF IS QUICK TO MOVE THE HIGH PRESSURE OUT OF THE REGION...PUSHED BY LOW PRESSURE MOVING INTO THE MID-ATLANTIC FROM THE GREAT LAKES. THE GFS KEEPS THAT HIGH PRESSURE OVER SOUTHERN NEW ENGLAND AND THE LOW PRESSURE IN THE GREAT LAKES. THURSDAY NIGHT THROUGH SATURDAY...THIS LOOKS TO BE THE MOST UNSETTLED TIME WITH LOW PRESSURE MOVING INTO THE MID-ATLANTIC AND THEN POSSIBLY UP THE EAST COAST OVER THE 40/70 BENCHMARK SOUTHEAST OF SOUTHERN NEW ENGLAND. THE ECMWF IS THE MOST BULLISH WITH THIS... TRACKING THE LOW DIRECTLY OVER THE BENCHMARK AND BRINGING AN EXTENDED PERIOD OF RAIN TO MUCH OF SOUTHERN NEW ENGLAND. THE GFS DEVELOPS SOME SORT OF BOUNDARY ALONG WHICH SEVERAL AREAS OF LOW PRESSURE TRAVEL...BRINGING PERIODS OF RAIN TO THE REGION. BELOW NORMAL TEMPERATURES ARE A GIVEN WITH LOWERING HEIGHTS/TEMPS ALOFT AND MOSTLY CLOUDY TO OVERCAST SKIES FOR MUCH OF THIS TIME. WOULDN/T BE SURPRISED TO SEE TEMPS TOP OUT IN THE UPPER 60S TO LOWER 70S ON FRIDAY. SUNDAY AND MONDAY...MUCH OF THIS FORECAST WILL DEPEND ON HOW FRIDAY AND SATURDAY SHAKE OUT...BUT IN GENERAL THE WEATHER LOOKS DRIER AND QUIETER WITH REBOUNDING TEMPERATURES. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM /THROUGH WEDNESDAY/... THROUGH 12Z...MODERATE CONFIDENCE. MAINLY VFR...WILL HAVE TO WATCH SOME LEFTOVER SHRA/TSTMS MOVING THROUGH NY/PA WHICH MAY IMPACT MAINLY CT DURING THE EARLY MORNING HOURS. TODAY...MODERATE CONFIDENCE. DEPENDING ON SUNSHINE...EXPECT SOME THUNDERSTORMS AND SHOWERS TO DEVELOP MID DAY AND CONTINUE...FROM W-E INTO THE EVENING HOURS. SOME OF THESE STORMS MAY BE SEVERE...WITH STRONG WINDS AND HAIL...AS WELL AS BRIEF MVFR/IFR CONDITIONS. TONIGHT INTO WEDNESDAY...HIGH CONFIDENCE. AFTER STORMS/RAIN SWEEPS OFFSHORE LATE THIS EVENING...EXPECT IMPROVEMENT TO VFR WHICH WILL LINGER INTO THE DAYLIGHT HOURS ON WED. AN ISOLATED SHOWER OR THUNDERSTORM IS THEN POSSIBLE MAINLY N OF THE MASS PIKE ON WED...BUT NOT AS WIDESPREAD AS TUE. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. LOWER CONFIDENCE IN TIMING OF ANY AFTERNOON STORMS. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. LOWER CONFIDENCE IN TIMING OF ANY AFTERNOON STORMS. OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/... WEDNESDAY NIGHT THROUGH THURSDAY...HIGH CONFIDENCE. VFR. LOW PROBABILITY OF A FEW SHOWERS/STORMS ACROSS NW MA WEDNESDAY. ANY STORMS THAT DEVELOP MAY HAVE MVFR/IFR CONDITIONS. THURSDAY NIGHT THROUGH SATURDAY...LOW CONFIDENCE ON TIMING...HIGHER CONFIDENCE ON TRENDS. MVFR/IFR CONDITIONS IN WIDESPREAD RAIN LIKELY SOMETIME DURING THIS PERIOD. VFR BEFORE AND AFTER PERIOD OF RAIN. && .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 TUESDAY NIGHT/... THROUGH TODAY...MODERATE CONFIDENCE. SW WINDS REMAIN IN PLACE AND WITH SOME GUSTS POTENTIALLY APPROACHING 25-30 KT AT TIMES. THIS WILL ALLOW SEAS...WHICH ARE ALREADY RUNNING AROUND 5 FT ON THE S WATERS TO INCREASE...POSSIBLY INCREASING TO AS HIGH AS 7 FT BY THE EVENING. SMALL CRAFT ADVISORIES CURRENTLY OUT REFLECT THIS...SO NO CHANGES. TONIGHT INTO WEDNESDAY...MODERATE CONFIDENCE. FRONT MOVES FURTHER OFFSHORE...OUTSIDE OF ANY STORMS/SHOWERS...WINDS AND SEAS WILL GRADUALLY DIMINISH...SO EXPECT THESE SMALL CRAFT ADVISORIES TO GRADUALLY BE DROPPED THROUGH THE PERIOD. OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/...MODERATE CONFIDENCE. WEDNESDAY NIGHT THROUGH FRIDAY...HIGH CONFIDENCE. QUIET BOATING WEATHER WITH LIGHT WINDS AND SEAS BELOW 5 FEET EXPECTED. RAIN IS LIKELY THURSDAY NIGHT THROUGH FRIDAY...LIMITING VISIBILITIES AT TIMES. FRIDAY NIGHT AND SATURDAY...MODERATE CONFIDENCE. EASTERLY WINDS AND SEAS INCREASE AS LOW PRESSURE PASSES SOUTH OF THE WATERS. SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED FOR THE OUTER WATERS. RAIN IS LIKELY FRIDAY NIGHT INTO SATURDAY...LIMITING VISIBILITIES AT TIMES.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ230>234-236-250-251. SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR ANZ235-237- 254>256.
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&& $$ SYNOPSIS...BELK/DOODY NEAR TERM...DOODY SHORT TERM...DOODY LONG TERM...BELK AVIATION...BELK/DOODY MARINE...BELK/DOODY

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