Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 031354 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 954 AM EDT MON AUG 3 2015 .SYNOPSIS...
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DRY WEATHER PREVAILS MUCH OF TODAY THEN THE THREAT OF SHOWERS AND THUNDERSTORMS RETURNS LATE TONIGHT TOWARDS TUESDAY MORNING. DRY... WARM AND LESS HUMID WEATHER ARRIVES WEDNESDAY AND CONTINUES INTO 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 /UNTIL 6 PM THIS EVENING/...
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10 AM UPDATE... SCATTERED SHOWERS SOME OF WHICH EVOLVING INTO THUNDERSTORMS HAVE ERUPTED SE OF NEW ENGLAND OVER THE WATERS. BENEATH FAVORABLE MID- LEVEL LAPSE RATES ALONG A LOW- TO MID-LEVEL GRADIENT OF HIGHER THETA-E AIR...CONVERGENCE IS LENDING TO DEVELOPMENT. BUT ACTIVITY IS STAYING LOW AND NOT BECOMING ROBUST DUE TO THE ABSENCE OF DEEP LAYER FORCING. ONLY INSTABILITY AND CONVERGENCE OF MOISTURE ARE AIDING IN THE PROCESS WITHIN AN ENVIRONMENT OF BULK SHEAR VALUES OF AROUND 25 KTS. COLLOCATED UPPER-LEVEL JET STREAK AND ATTENDANT VENTING AIDING AS WELL. FEEL THE ENVIRONMENT WILL CONTINUE THROUGH THE DAY AND THUS HAVE INCREASED THE RAIN CHANCES ACROSS THE SE WATERS. UNCERTAIN AS TO PRECIP CHANCES OVER THE CAPE/ISLANDS. WILL HAVE TO WATCH CLOSELY AND AS TO WHETHER WE CAN GENERATE SOME UPPER-LEVEL SUPPORT VIA A COLLOCATED AFOREMENTIONED H3 JET STREAK. AGAIN...FORCING APPEARS TO BE CONVERGENT RELATED SO WITH ANY LATER ACTIVITY FEEL IT WILL REMAIN SUB-SEVERE. OTHERWISE A WARM AND HUMID DAY ESPECIALLY FOR SE NEW ENGLAND AS TEMPERATURES TOP OUT INTO THE UPPER-80S TO LOW-90S WITH DEWPOINTS AROUND THE MID-60S. DRIER N/W WITH UPPER-50 TO LOW-60 DEWPOINTS. A MIX OF SUN AND CLOUDS UNDER BREEZY SW-WINDS GUSTING 20-25 MPH. AGREE WITH THE PRIOR FORECAST TEAM THAT LITTLE HEIGHT FALLS ARE ANTICIPATED TODAY BENEATH MID-LEVEL DRY AIR PER 12Z SOUNDINGS. RIDGE SHOULD HOLD IN PLACE ACROSS THE REGION KEEPING OUR AREA DRY. THUS CONVECTIVE ACTIVITY SHOULD REMAIN MOSTLY N AND W BUT IT IS NOT OUT OF THE QUESTION THAT THE REMNANTS AS WELL AS THE CONVECTIVE ENVIRONMENT OF BETTER INSTABILITY AND FORCING CAN DRIFT INTO NW MA TOWARDS THE END OF THE PERIOD INTO EVENING WITH THE MEAN WIND. CHANCE POPS FOR NOW.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... *** POSSIBLE STRONG TO SEVERE T-STORMS LATER TONIGHT INTO TUE *** TONIGHT... MORE POTENT TRAILING SHORT WAVE TROUGH APPROACHES SOUTHERN NEW ENGLAND FROM THE WEST. THIS IS QUITE EVIDENT IN WIND FIELDS ALOFT WHERE 500 MB SPEEDS APPROACH 50 KTS! THIS SHORT WAVE TROUGH COOLS H5 TEMPS TO -11C/-12C. THIS COMBINED WITH SURFACE DEW PTS INCREASING INTO THE U60S AND L70S PROVIDES MUCAPES GREATER THAN 2000J/KG AND MID LEVEL LAPSE RATES BETWEEN 6.5 AND 7.0C/KM BY 12Z TUE ACROSS RI AND EASTERN MA PER 00Z EC AND 00Z GFS! EVEN THE COURSE 00Z GEFS HAS THE SAME SIGNAL AND STRENGTH. THIS AMOUNT OF INSTABILITY COMBINED WITH DEEP LAYER SHEAR UP TO 50 KT PROVIDES AN ENVIRONMENT FAVORABLE FOR SEVERE STORMS. ONLY UNCERTAINTY IS WILL THERE BE ENOUGH FORCING FOR ASCENT TO UNLEASH THIS STRONG INSTABILITY. MIXED SIGNALS WITHIN THE GUIDANCE WITH THE GFS AND ECMWF NOT GENERATING MUCH QPF TONIGHT WHILE THE HI RES GUID NMM AND ARW HAVE CONVECTION BUT WEAKENING AS IT CROSSES THE AREA FROM WEST TO EAST. SOMEWHAT DISCOUNTING THE NAM GIVEN IT/S HIGH BIASED DEW PTS AND CORRESPONDING INSTABILITY PARAMETERS. THUS LOW FORECAST CONFIDENCE ON AREAL COVERAGE AND INTENSITY OF CONVECTION. HOWEVER IF STORMS CAN FIRE STRONG TO DAMAGING WINDS WILL BE A CONCERN. LOW LEVEL SHEAR IS IMPRESSIVE TOO ALONG WITH SUFFICIENT INSTABILITY AND LOW LCLS /HIGH DEW PTS/ FOR A LOW RISK OF AN ISOLATED TORNADO. IT WILL BE A WARM AND HUMID NIGHT WITH DEW PTS RISING THROUGH THE U60S AND L70S. TUESDAY... FORECAST UNCERTAINTY CONTINUES AS AREAL COVERAGE OF NOCTURNAL CONVECTION AND CLOUD DEBRIS FROM TONIGHT WILL IMPACT IF NEW CONVECTION FIRES DURING THE DAY TUES. SHORT WAVE TROUGH MOVES ACROSS THE AREA ALONG WITH ATTENDING SURFACE TROUGH. THIS SHOULD PROVIDE ENOUGH FORCING FOR ASCENT TO INITIATE CONVECTION. DEEP LAYER MOISTURE AND INSTABILITY APPEARS TO BE FOCUSED ACROSS RI AND EASTERN MA. THUS RISK OF STORMS GREATEST ACROSS THIS AREA. WINDS FIELDS REMAIN IMPRESSIVE SO RISK OF STRONG TO DAMAGING WINDS CONTINUES. ANOTHER WARM DAY WITH HIGHS WELL INTO THE 80S ALONG WITH DEW PTS IN THE U60S TO L70S. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * UNSETTLED WEATHER POSSIBLE AROUND FRIDAY * TEMPERATURES TRENDING BELOW NORMAL DURING THIS PERIOD OVERVIEW... 00Z GUIDANCE IS IN DESCENT AGREEMENT FOR THIS PORTION OF THE FORECAST. UPPER LEVEL LOW OVER JAMES BAY WILL BEGIN ITS EASTWARD MOVEMENT TOWARDS THE MARITIMES. ELONGATED TROUGH WILL SET UP OVER THE REGION BEFORE TRENDING TOWARDS A ZONAL FLOW. SEVERAL SOUTHERN STREAM WAVES WILL MOVE THROUGH AND TRIES TO BRING A FEW COASTAL SYSTEMS TOWARDS SNE. THE PATTERN DOES NOT SEEM THAT AMPLIFIED TO MAKE IT A CLASSIC COASTAL LOW...HOWEVER UPPER LEVEL JET MAY BRING A FEW SYSTEMS JUST SOUTH OF THE REGION. BECAUSE OF THE UNCERTAINTY AT THE END OF THE WEEK...TRENDED TOWARDS THE ENSEMBLES WHICH INDICATE PRECIP AROUND LATE THURSDAY INTO FRIDAY AND AGAIN POSSIBLE SATURDAY/SUNDAY. THIS UNSEASONABLE PATTERN WILL LEAD TO BELOW NORMAL TEMPERATURES TOWARD THE END OF THE WEEK INTO THE WEEKEND. DAILIES... WEDNESDAY INTO THURSDAY...MODERATE CONFIDENCE. A FEW LINGERING SHOWERS AND THUNDERSTORMS OVER THE WATERS AS COLD FRONT PASSES THROUGH LATE TUESDAY NIGHT. SHORTWAVE WILL PUSH THROUGH ON WEDNESDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. UPPER LEVEL TROUGH WILL ALLOW FOR CYCLONIC FLOW AND COLD AIR ALOFT...RESULTING IN A FEW AFTERNOON INSTABILITY SHOWERS ACROSS THE HIGHER TERRAIN. OTHERWISE IT WILL BE A MIX OF CLOUDS AND SUNSHINE. CYCLONIC FLOW WILL STILL BE ALOFT BY THURSDAY BUT COLD AIR ALOFT WILL BE FOCUS MORE ACROSS NORTHERN NEW ENGLAND. THEREFORE BELIEVE THURSDAY WILL BE DRY WITH A MIX OF SUN AND CLOUDS. TEMPERATURES WILL BE COOLER THAN NORMAL BOTH DAYS WITH SNE REACHING INTO THE 80S ON WEDNESDAYS BUT BELOW 80 ON THURSDAY. THURSDAY NIGHT INTO FRIDAY...MODERATE CONFIDENCE. POTENT SHORTWAVE WILL TRY TO DEVELOP A SOUTHERN WAVE DURING THE END OF THE WORK WEEK. BOTH ENSEMBLE MEMBERS AS WELL AS THE OPERATIONS EC BRINGS PRECIP TO THE REGION DURING THIS TIME FRAME. THEREFORE HAVE INCREASED PRECIP CHANCES ACROSS THE SOUTH COAST WHERE CONFIDENCE IS HIGHEST. SNE WILL BE ON THE NORTHERN SIDE OF THIS SYSTEM SO ANY SHIFT IN THE PATTERN WILL MOVE THE PRECIP CHC FOR THE REGION. FINALLY BEING ON THE NORTH-SIDE OF THE SYSTEM...TEMPERATURES WILL BE UNSEASONABLE COOLER. IN FACT TEMPERATURES WILL STRUGGLE TO GET ABOVE 80F. SATURDAY AND BEYOND...MODERATE CONFIDENCE. ANOTHER SOUTHERN STREAM WAVE TRIES TO DEVELOP OVER THE WEEKEND. LOW CONFIDENCE ON IF THE PATTERN WILL BRING THIS LOW TO SNE. HAVE KEPT A LOW CHC AS GUIDANCE CONTINUES TO FLIP-FLOP DURING THE TIMEFRAME. OTHERWISE...TEMPERATURES WILL BEGIN TO MODERATE OVER THE WEEKEND INTO NEXT WEEK AS UPPER LEVEL RIDGE OVER THE CONUS BEGINS TO BUILD AGAIN. && .AVIATION /14Z MONDAY THROUGH FRIDAY/...
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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/... TODAY...HIGH CONFIDENCE. VFR AND DRY. TSRA IN NY STATE THIS AFTERNOON MAY CLIP W LATE. SSW WINDS INCREASING WITH GUSTS UP TO 20-25 KT. TONIGHT...LOW CONFIDENCE. LOTS OF UNCERTAINTY ON AREAL COVERAGE AND INTENSITY OF POTENTIAL TSRA. VFR TO START BUT LOWERING TO MVFR AND PROBABLY IFR IN LOW CLOUDS AND FOG ACROSS RI AND SE MA. TUESDAY...LOW CONFIDENCE. LOTS OF UNCERTAINTY ON AREAL COVERAGE AND INTENSITY OF POTENTIAL TSRA. A MIX OF MVFR AND IFR IN THE MORNING AS LOW CLOUDS AND FOG IMPACT THE TERMINALS. LIKELY IMPROVING TO VFR IN THE AFTERNOON. KBOS TERMINAL...HIGH CONFIDENCE IN TAF TODAY THEN LOWERING TONIGHT AND TUE. KBDL TERMINAL...HIGH CONFIDENCE IN TAF TODAY THEN LOWERING TONIGHT AND TUE. OUTLOOK /TUESDAY NIGHT THROUGH FRIDAY/... WEDNESDAY...MODERATE CONFIDENCE. MAINLY VFR. COULD SEE MVFR IN SHOWERS ACROSS HIGHER TERRAIN. THURSDAY INTO FRIDAY...LOW CONFIDENCE. A PERIOD OF SHOWERS AND MVFR/IFR POSSIBLE BUT TIMING IS UNCERTAIN. LATEST INDICATIONS ARE THAT BEST CHANCE FOR WET WEATHER WILL BE ON FRI.
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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 MONDAY NIGHT/... TODAY...HIGH CONFIDENCE. SSW WINDS INCREASE TO 15 TO 20 KT WITH GUSTS UP TO 25 KT. SEAS INCREASE ESPECIALLY ACROSS THE SOUTH COASTAL WATERS. TONIGHT...MODERATE CONFIDENCE. SSW WINDS 15 TO 20 KT. GUSTS UP TO 25 KT POSSIBLE. PATCHY FOG WILL LIMIT VSBY. A FEW STRONG T-STORMS POSSIBLE ESPECIALLY AFTER MIDNIGHT. LOW CONFIDENCE ON T-STORM FORECAST. TUESDAY...MODERATE CONFIDENCE. SSW WINDS 15 TO 20 KT WITH GUSTS UP TO 25 KT POSSIBLE. PATCHY MORNING FOG MAY REDUCE VSBY. A FEW STRONG T-STORMS POSSIBLE. LOW CONFIDENCE ON T-STORM FORECAST. OUTLOOK /TUESDAY NIGHT THROUGH FRIDAY/...MODERATE CONFIDENCE. WEDNESDAY...MODERATE CONFIDENCE. W/SW WINDS BELOW SCA BUT GUSTS TO 20 KT POSSIBLE. SEAS SUBSIDING. THURSDAY INTO FRIDAY...LOW CONFIDENCE. WINDS AND SEAS WILL DEPEND ON TRACK AND TIMING OF LOW PRES APPROACHING THE REGION. COULD SEE A PERIOD OF GUSTY NE WINDS...ESPECIALLY FRI.
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&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 8 PM EDT TUESDAY FOR ANZ230>237-250-251-254>256. && $$ SYNOPSIS...NOCERA/DUNTEN NEAR TERM...NOCERA/DUNTEN/SIPPRELL SHORT TERM...NOCERA LONG TERM...DUNTEN AVIATION...NOCERA/DUNTEN MARINE...NOCERA/DUNTEN

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