Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 030819 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 419 AM EDT MON AUG 3 2015 .SYNOPSIS... DRY WEATHER PREVAILS MUCH OF TODAY THEN THE THREAT OF SHOWERS AND THUNDERSTORMS RETURNS THIS EVENING INTO TUE. 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. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 4 AM UPDATE... QUITE THE CONVECTIVE COMPLEX EARLY THIS MORNING OVER THE OH VLY. MODELS APPEAR TO BE SIMULATING THIS CONVECTION FAIRLY WELL SO FORECAST CONFIDENCE IS HIGH REGARDING TODAY/S FORECAST FOR SOUTHERN NEW ENGLAND. GOOD MODEL AGREEMENT THAT LEAD SHORT WAVE OVER THE GREAT LAKES WILL EJECT NORTHEAST INTO WESTERN NY STATE TODAY AND THEN INTO NORTHERN VT AND ST LWRN RVR VLY THEREAFTER. THIS RESULTS IN LITTLE IF ANY HEIGHT FALLS ACROSS SOUTHERN NEW ENGLAND TODAY. THUS SHOULD BE ENOUGH EAST COAST RIDGING AND ASSOCIATED MID LEVEL DRY AIR TO PRECLUDE ANY STORMS FROM FORMING OR TRACKING INTO THE AREA. THE ONE EXCEPTION IS ACROSS WESTERN MA...CLOSER TO THE JET ENERGY/MOISTURE AND INSTABILITY AXIS. THEREFORE THERE IS A LOW RISK FOR A FEW STORMS LATE IN THE DAY TO POSSIBLY CLIP WESTERN MA. OTHERWISE REMAINDER OF THE REGION SHOULD REMAIN DRY. LOW CLOUDS...PATCHY FOG AND DRIZZLE WILL LIKELY IMPACT PARTS OF RI AND SOUTHEAST MA THIS MORNING...AS STRATUS ALREADY DEVELOPING AND OVERSPREADING THIS REGION. THIS LOW LEVEL MOISTURE SHOULD ERODE OR LIFT INTO A STRATOCU DECK BY AFTERNOON...YIELDING PARTLY SUNNY CONDITIONS. ELSEWHERE PARTLY TO MOSTLY SUNNY SKIES SHOULD PREVAIL. SOUTH-SOUTHWEST LOW LEVEL FLOW HAS RESULTED IN DEW PTS RISING OVERNIGHT INTO THE 60S TO AROUND 70 ACROSS RI AND SOUTHEAST MA. THUS MORE HUMID THAN YESTERDAY. WEAK LOW LEVEL WARM AIR ADVECTION WILL RESULT IN TEMPS MAKING A RUN AT 90 AWAY FROM THE SOUTH COAST. THEREFORE MOST LOCATIONS WILL SEE HIGHS TODAY 85 TO 90. AN INCREASING SSW WIND OF 15 TO 20 MPH WITH GUSTS UP TO 25 MPH THIS AFTERNOON WILL HELP TAKE SOME OF THE EDGE OFF THE WARM AND HUMID CONDITIONS. && .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 /08Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. TODAY...VFR AND DRY WEATHER FOR MOST TERMINALS. THE EXCEPTION WILL BE ALONG THE SOUTH COAST OF MA AND RI WHERE PATCHY IFR IN FOG AND DRIZZLE IS POSSIBLE THIS MORNING...THEN BURNING OFF BY MIDDAY. ALSO T-STORMS IN NY STATE THIS AFTERNOON MAY CLIP WESTERN MA LATE IN THE DAY. SSW WINDS INCREASE THIS AFTERNOON WITH GUSTS UP TO 20-25 KT POSSIBLE. MODERATE TO HIGH FORECAST CONFIDENCE. TONIGHT...LOTS OF UNCERTAINTY ON AREAL COVERAGE AND INTENSITY OF POTENTIAL T-STORMS. THUS LOW CONFIDENCE FORECAST HERE. VFR TO START BUT LOWERING TO MVFR AND PROBABLY IFR IN LOW CLOUDS AND FOG ACROSS RI AND SOUTHEAST MA. TUESDAY...LOTS OF UNCERTAINTY ON AREAL COVERAGE AND INTENSITY OF POTENTIAL T-STORMS. THUS LOW CONFIDENCE FORECAST HERE. 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. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM /THROUGH MONDAY NIGHT/... TODAY... SSW WINDS INCREASE TO 15 TO 20 KT WITH GUSTS UP TO 25 KT. SEAS INCREASE ESPECIALLY ACROSS THE SOUTH COASTAL WATERS. PATCHY FOG AND DRIZZLE IMPACT THE SOUTH WATERS THIS MORNING. IMPROVING THIS AFTERNOON. MODERATE TO HIGH CONFIDENCE. TONIGHT... 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... 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. && .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 SHORT TERM...NOCERA LONG TERM...DUNTEN AVIATION...NOCERA/DUNTEN MARINE...NOCERA/DUNTEN

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