Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 081122 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 722 AM EDT TUE JUL 8 2014 .SYNOPSIS... VERY WARM/HOT AND HUMID WEATHER WILL PERSIST THROUGH MID WEEK. WHILE MUCH OF THE TIME WILL BE DRY...A FEW STRONG HIT AND MISS THUNDERSTORMS WILL BE POSSIBLE AT TIMES ESPECIALLY ACROSS THE INTERIOR. SHOWERS OR AN ISOLATED THUNDERSTORM ARE POSSIBLY MAINLY NEAR THE SOUTH COAST ON THURSDAY. DRY WEATHER WITH LOWER HUMIDITY WILL ARRIVE BY THE END OF THE WEEK INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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7 AM UPDATE... FOR THE MOST PART...FORECAST PARAMETERS ARE ON TRACK THIS MORNING. WILL ADJUST TEMPS/DWPTS AND SKIES TO BRING THEM UP TO CURRENT TRENDS. JUST SEEING SOME MID-UPPER LVL CLOUDS ACROSS THE REGION WHICH ARE THE REMAINS OF CONVECTION FROM LATE LAST EVENING UPSTREAM. OTHERWISE...EXPECT MAINLY PARTLY CLOUDY CONDITIONS TODAY...WITH FULL MIXING AND SUNSHINE EXPECTED TO INCHTEMPERATURES UP A DEGREE OR SO FROM YESTERDAY. MAINLY UPPER 80S TO LOW 90S. AT THIS TIME...DID NOT HAVE ENOUGH TO CHANGE TIMING/LOCATION OF ANY POPS. TODAY... UPPER LEVEL TROUGH WILL CONTINUE TO SET-UP ACROSS THE NORTHERN U.S. TODAY AND INTO TOMORROW. TODAYS FOCUS IS ONCE AGAIN ON THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS...WHICH COULD BE STRONG TO SEVERE. HOWEVER THERE ARE A LOT OF PARAMETERS THAT NEED TO LINE UP FOR THIS TO OCCUR SO OVERALL HAVE A MODERATE CONFIDENCE ON THE FORECAST. DURING THE DAY...EXPECT HIGH TEMPS TO WARM WELL INTO THE UPPER 80S TO LOW 90S. ANTICIPATE SLIGHTLY COOLER TEMPS ACROSS THE SOUTH COAST THANKS TO SW FLOW PUSHING COOLER MARITIMES AIR ON LAND. DEWPOINTS AS WELL WILL INCREASE INTO THE UPPER 60S INTO LOW 70S KEEPING THE MUGGY AIR AROUND. INSTABILITY WILL INCREASE DURING THE DAY TO ABOVE 2000 J/KG WITH 0- 3KM BULK SHEAR VALUES BETWEEN 35-40 KTS. THIS IS SIGNIFICANTLY MORE SHEAR THEN YESTERDAY. THE ATMOSPHERE SHOULD BE PRIMED TODAY FOR THE POTENTIAL FOR THUNDERSTORMS BUT THE UNCERTAINTY IS ON THE TRIGGER POTENTIAL. BELIEVE A FEW ISOLATED SHOWERS MAY DEVELOP LATE THIS AFTERNOON WHETHER IT IS FROM OROGRAPHIC LIFT OR REACHING THE CONVECTIVE TEMP. COVERAGE COULD INCREASE CLOSER TO 00Z AS AN UPPER LEVEL SHORTWAVE WILL MOVE OVER THE REGION AROUND 00Z-06Z. THERE IS THE POTENTIAL FOR STRONG TO PERHAPS A FEW SEVERE THUNDERSTORMS WITH STRONG GUSTY WINDS BEING THE MAIN THREAT. BEST REGION FOR THIS TO OCCUR IS NORTH AND WEST THE BOS TO PVD LINE. PWAT VALUES INCREASE CLOSER TO 1.5-2 INCHES THROUGH THE EVENING HOURS LEADING TO HEAVY RAINFALL AND THE POSSIBILITY OF LOCALIZED FLOODING.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... TONIGHT... UPPER LEVEL SHORTWAVE WILL MOVE ACROSS THE REGION TONIGHT. BELIEVE ANY CONVECTION THAT IS ONGOING WILL CONTINUE AS SHORTWAVE WILL KEEP THE CONVECTION POTENTIAL ALIVE. GUIDANCES INDICATES THAT INSTABILITY AND EVEN SHEAR VALUES INCREASE SLIGHTLY OVERNIGHT ALLOWING FOR AN INCREASE IN CONFIDENCE THAT THE POTENTIAL FOR STRONG STORMS MAY OCCUR. LLJ WILL ALSO INCREASING ALLOWING FOR ANY CONVECTION TO DEVELOP OR CONTINUE INTO THE OVERNIGHT HOURS. PWAT VALUES DO INCREASE CLOSER TO 2 INCHES SO ANY STRONG THUNDERSTORMS MAY RESULT IN LOCALIZE FLOODING. TOMORROW... UPPER LEVEL TROUGH WILL CONTINUE TO SPIN OVER THE REGION...BUT WILL BEGIN TO PUSH OUT OF THE REGION BY THE EVENING HOURS. THIS TROUGH WILL ROUND A STRONG SHORTWAVE PUSHING A SLOW MOVING COLD FRONT ACROSS THE REGION. SINCE THE AIRMASS WILL STILL BE WARM AND MUGGY ANTICIPATE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WITH THE POTENTIAL FOR STRONG THUNDERSTORMS TO OCCUR. INSTABILITY VALUES WILL INCREASE TO 2000 J/KG AND 0-3 KM BULK SHEAR VALUES ARE STILL 25-30 KTS. RIGHT ENTRANCE REGION OF THE JET STREAK WILL ALSO SET UP OVER THE REGION INCREASING THE LIFT EVEN MORE. ONLY CAVEAT IS THE LACK OF DEEP LAYER MOISTURE AS DRY AIR DOES MOVE INTO THE REGION. RIGHT NOW BELIEVE THAT LOCATION SOUTH AND EAST OF A MHT-ORH-BDL LINE HAS THE BEST CHANCE FOR STRONG TO MAYBE SEVERE WEATHER ON WEDNESDAY. PWAT VALUES WILL STILL BE HIGH...CLOSE TO 2 INCHES SO HEAVY DOWNPOURS ARE A MAIN THREAT AS WELL AS GUSTY WINDS AND SMALL HAIL. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... HIGHLIGHTS... * A FEW THUNDERSTORMS POSSIBLE WED NIGHT INTO THU * DRIER AND LESS HUMID AIR RETURNS BY THE END OF THE WEEK OVERVIEW AND MODEL PREFERENCES... OVERALL...BOTH OPERATIONAL AND ENSEMBLE MODELS ARE IN FAIR AGREEMENT THROUGH THE LONG TERM. LONGWAVE TROF WILL BE LIFTING THROUGH NEW ENGLAND THROUGH THE...AS THE SFC REFLECTION...A COLD FRONT SLIDES FURTHER OFFSHORE. THE UPPER PATTERN SHIFT FORCES A ZONAL FLOW ACROSS THE REGION...ALLOWING DRIER AND MORE SEASONAL AIRMASS TO MOVE INTO PLACE. THEN YET ANOTHER DEEP CUTOFF TRIES TO DEVELOP THANKS TO SHORTWAVE ENERGY DIVING S FROM N CENTRAL CANADA. WHILE THERE IS SOME DISAGREEMENT ON WHERE THE CORE OF THIS CUTOFF ULTIMATELY RESIDES BY THE TIME IT SETTLES NEXT WEEK...THEY ARE ALL IN AGREEMENT THAT THIS CUTOFF WILL FORM TO OUR W. THEREFORE...WILL LIKELY SEE ANOTHER ROUND OF SW FLOW AND POTENTIAL FOR UNSETTLED AND WET CONDITIONS BY NEXT WEEK. GIVEN THE AGREEMENT...ANOTHER BLEND OF GUIDANCE WILL BE USED AS BASELINE. DETAILS... WED NIGHT INTO THU... CURRENT TIMING OF THE FINAL COLD FRONT HAS IT SLIDING ACROSS SRN NEW ENGLAND SLOWLY...MAINLY BETWEEN 00Z AND 12Z THU. AHEAD OF THE FRONT...HIGH DWPTS IN THE UPPER 60S TO AROUND 70 STILL SUPPORT 500-800J/KG OF ML CAPE COINCIDENT WITH REMAINING 40 KT OF 0-6KM SHEAR. THEREFORE...NOT OUT OF THE QUESTION THAT SOME CONVECTIVE ACTIVITY MAY CONTINUE INTO THE OVERNIGHT HOURS ESPECIALLY S OF THE MASS PIKE AND ALONG THE WATERS. HIGH SHEAR MAY PROMOTE GUSTY WINDS OR HAIL AS WELL. THE MAIN FLY IN THE OINTMENT IS DRYING IN THE MID LVLS WHICH MAY PRECLUDE CONVECTION SOMEWHAT...SO FOR NOW MOST POPS ARE CHANCE OR BELOW. THE KEY MAY BE ANYTHING THAT FORMS DURING THE AFTERNOON/EVENING WED WHICH WOULD BE WITHIN A MOIST COLUMN AND IS HELD TOGETHER BY THE SHEAR. BY THU...THE THREAT FOR SHOWERS OR AN ISOLATED STORM MAY LINGER UNTIL THE FRONT IS ABLE TO PUSH FURTHER OFFSHORE. THEREFORE...HAVE GRADUALLY LOWERING POPS THROUGH THE DAY. STILL WARM ON THU LIKELY AS THE MID LVL TEMPS ARE LIKELY TO BE SLOW TO CHANGE. SO WILL CONTINUE WITH HIGHS ABOVE NORMAL. FRI AND SAT... HIGH PRES MOVES IN FROM THE W AS W-E ZONAL FLOW DEVELOPS ALOFT. THIS NW FLOW WILL ALLOW THE PERSISTENT HUMIDITY EARLY THIS WEEK TO FINALLY BREAK WITH DWPTS BEING ALLOWED TO FALL INTO THE LOW-MID 50S. H85 TEMPS EACH DAY RANGE AROUND +12 TO +14C...WHICH SUGGEST HIGHS NEAR SEASONAL NORMALS OR IN THE LOW-MID 80S. SUN INTO MON... A GRADUALLY DEVELOPING CUTOFF TO THE W WILL YIELD INCREASING RETURN FLOW THROUGH THE PERIOD. THEREFORE...EXPECT INCREASING HUMIDITY AND COLUMN MOISTURE THROUGH THE PERIOD...AS WELL AS WARMER TEMPERATURES. ENSEMBLES SUGGEST THAT BY MON...PWATS MAY APPROACH 2 STD DEVIATIONS FROM NORMAL. ALTHOUGH THERE ARE SOME DISAGREEMENTS ON EXACTLY HOW IT TURNS OUT. BY SUN...WARM FRONT WILL MOVE INTO NRN NEW ENGLAND YIELDING THE POSSIBILITY OF SHOWERS OR POSSIBLY AN ISOLATED RUMBLE OF THUNDER. THE HIGHER THREAT LOOKS TO BE MON INTO TUE...AS ANOTHER SLOW MOVING COLD FRONT APPROACHES FROM THE W...IN WHAT COULD BE A MOISTURE RICH AND POTENTIALLY UNSTABLE AIRMASS. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/...
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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 WEDNESDAY/... TODAY INTO TONIGHT...MODERATE CONFIDENCE. MAINLY VFR TODAY. THE ONLY CAVEAT WILL BE FOR ISOLATED MVFR/IFR CONDITIONS IN LATE AFTERNOON SHOWERS AND THUNDERSHOWERS...THE FOCUS OF WHICH WILL BE NW MA AND SW NH. SW WINDS ONCE AGAIN WITH GUSTS 20-25 KT. BY THIS EVENING...LOW PROBABILITY OF SOME FOG AND LOW STRATUS LATE MAINLY ALONG PORTIONS OF THE S COAST. ALSO...POSSIBLE SHOWERS AND THUNDERSTORMS CONTINUE IN SPOTS THROUGH THE OVERNIGHT. WEDNESDAY...MODERATE CONFIDENCE. VFR CONDITIONS ESPECIALLY NORTH AND WEST OF A MHT-ORH-BDL LINE. SOUTH AND EST OF THE LINE...EXPECT VFR CONDITIONS WITH LOCALIZED MVFR ON SHOWERS AND THUNDERSTORMS. KBOS TAF...HIGH CONFIDENCE IN TAF THROUGH THE DAY. KBDL TAF...HIGH CONFIDENCE IN TAF. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... WED NIGHT INTO THU...MODERATE CONFIDENCE. MAINLY VFR. SHOWERS OR AN ISOLATED THUNDERSTORM POSSIBLE MAINLY NEAR THE S COAST WITH BRIEF MVFR/IFR CONDITIONS. ALL VFR EXPECTED BY LATE IN THE DAY THU. FRI INTO SAT...HIGH CONFIDENCE. MAINLY VFR.
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&& .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH WEDNESDAY/...HIGH CONFIDENCE. PERSISTENT SOUTHWEST FLOW WILL CONTINUE TONIGHT AHEAD OF A SLOW MOVING COLD FRONT. WINDS MAY GENERALLY BE 15-20 KTS BUT ACROSS THE NEAR SHORE WATERS OF THE CAPE AND BUZZARD BAY MAY SEE 25KTS SO HAVE ISSUED A SCA. OTHERWISE SCA CONTINUES FOR OUTER WATERS FROM THE LONG SOUTHWEST FETCH RESULTING IN 4 TO 7 FOOT SEAS. OTHERWISE...MAY SEE AREAS OF FOG DEVELOP TONIGHT WHICH COULD BE LOCALLY DENSE ACROSS THE SOUTHERN WATERS. IN ADDITION...LOW TO MODERATE PROBABILITY FOR A FEW STRONG THUNDERSTORMS TO MOVE ACROSS THE NEAR SHORE WATERS THIS EVENING AND TONIGHT AND AGAIN ON WEDNESDAY. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY. WEDNESDAY NIGHT INTO THURSDAY...MODERATE CONFIDENCE. A COLD FRONT WILL BE MOVING OFF THE SRN WATERS WED NIGHT. THIS MEANS SHOWERS AND AN ISOLATED THUNDERSTORM IS POSSIBLE THROUGH ABOUT MID DAY THU. OTHERWISE...SEAS WILL GRADUALLY BE DECLINING THROUGH THE PERIOD FROM ABOUT 5-6 FT ON THE OCEAN WATERS. THEREFORE...OUTSIDE OF ANY STORMS...SMALL CRAFT ADVISORIES ARE LIKELY TO BE COMING DOWN INTO EARLY THU. FRI AND SAT...HIGH CONFIDENCE. MAINLY QUIET BOATING WEATHER WITH HIGH PRESSURE. WINDS AND SEAS BELOW SMALL CRAFT THRESHOLDS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 11 AM EDT WEDNESDAY FOR ANZ231>234. SMALL CRAFT ADVISORY UNTIL 9 PM EDT WEDNESDAY FOR ANZ235-237- 254>256. && $$ SYNOPSIS...DOODY/DUNTEN NEAR TERM...DOODY/DUNTEN SHORT TERM...DUNTEN LONG TERM...DOODY AVIATION...DOODY/DUNTEN MARINE...DOODY/DUNTEN

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