Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 081512 AFDBOX AREA FORECAST DISCUSSION...MARINE UPDATE NATIONAL WEATHER SERVICE TAUNTON MA 1110 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/... ***LOW CONFIDENCE FORECAST ON CONVECTIVE POTENTIAL THIS AFTERNOON AND EVENING*** 925 AM UPDATE... ANOTHER VERY WARM/HOT AND HUMID DAY ON TAP FOR SOUTHERN NEW ENGLAND. 850 MB TEMPS AROUND +16C TO +17C SHOULD YIELD HIGH TEMPS IN THE UPPER 80S TO LOWER 90S FOR MUCH OF THE REGION. SOUTH TO SOUTHWEST WINDS BLOWING OFF THE OCEAN WILL RESULT IN TEMPS A FEW DEGREES COOLER ON THE IMMEDIATE SOUTH COAST AND PARTICULARLY NANTUCKET. ANOTHER LOW CONFIDENCE FORECAST IN TERMS OF POTENTIAL CONVECTION THIS AFTERNOON AND EVENING. A BATCH OF MID LEVEL CLOUDINESS WAS LOCATED ACROSS OUR SOUTHWEST ZONES AT MID MORNING...WITH EVEN A FEW SPRINKLES. THERE APPEARS TO BE A VERY SUBTLE SHORTWAVE THAT WILL BE LIFTING ACROSS THE REGION LATER THIS MORNING AND INTO THE AFTERNOON. THE HRRR/RAP/NAM MODELS TRY TO BLOSSOM CONVECTION AS IT LIFTS NORTHEAST LATER THIS MORNING AND AFTERNOON. NOT SURE IF ITS OVERDONE BECAUSE OTHER MODELS HAVE IT PRETTY QUIET RIGHT THROUGH THE AFTERNOON. HOWEVER...SINCE WE ARE EXPECTING 1000 TO 2000 J/KG OF CAPE ALONG WITH 30 TO 40 KNOTS OF 0 TO 6 KM SHEAR WILL HAVE TO WATCH THINGS CLOSELY. "IF" WE ARE ABLE TO GET A FEW STORMS GOING THIS AFTERNOON THEY COULD BECOME STRONG TO SEVERE GIVEN ENVIRONMENTAL CONDITIONS. THE MAIN THREAT WOULD BE STRAIGHT LINE DAMAGING WINDS WITH A SECONDARY CONCERN OF HAIL. PWATS BETWEEN 1.5 AND 2 INCHES WOULD ALSO ALLOW FOR TORRENTIAL RAINFALL WITH ANY OF THE ACTIVITY. HOWEVER...WE CERTAINLY COULD END UP DRY RIGHT THROUGH EARLY THIS EVENING WITH A LACK OF SIGNIFICANT FORCING. JUST GOING TO HAVE PLAY THINGS CONDITIONALLY AND COVER FORECAST WITH LOW POPS FOR NOW. WILL ALSO HAVE TO WATCH FOR A SECONDARY BATCH OF CONVECTION THAT MAY TRY TO WORK INTO OUR WESTERN ZONES THIS EVENING...BUT LOW CONFIDENCE ON HOW WELL IT WILL HOLD TOGETHER. && .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 /13Z 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/... 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. && .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. HAVE EXPANDED SCA HEADLINES TO INCLUDE ALL NEAR SHORE WATERS FOR THIS AFTERNOON/EARLY EVENING FOR GUSTS OF 25 KNOTS. OTHERWISE SCA CONTINUES FOR OUTER WATERS FROM THE PERSISTENT 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 UNTIL 11 AM EDT WEDNESDAY FOR ANZ231>234. SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ230-236-251. SMALL CRAFT ADVISORY UNTIL 9 PM EDT WEDNESDAY FOR ANZ235-237- 254>256. && $$ SYNOPSIS...DOODY/DUNTEN NEAR TERM...FRANK SHORT TERM...DUNTEN LONG TERM...DOODY AVIATION...DOODY/DUNTEN MARINE...DOODY/DUNTEN

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