Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 271753 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 153 PM EDT THU AUG 27 2015 .SYNOPSIS... HIGH PRESSURE WILL BE IN CONTROL BRINGING DRY AND SEASONABLE WEATHER THROUGH FRIDAY. THE HIGH MOVES OFFSHORE WITH A WARMING TREND THIS WEEKEND FOLLOWED BY INCREASING HEAT AND HUMIDITY FOR NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 2 PM UPDATE... COLD AIR ADVECTION/POST FRONTAL STRATO-CU A BIT MORE WIDESPREAD THAN PREVIOUS THOUGHT. THUS HAVE INCREASED CLOUD COVER IN OUR FORECAST DATABASE FOR THE REMAINDER OF THE DAY. IN FACT THE COLD AIR ALOFT /ABOUT -1 STD DEVIATION COLDER THAN CLIMO AT 850 MB AND 700 MB/ COMBINED WITH LAKE TEMPS AROUND 70F IS YIELDING A DELTA-T OF ABOUT 15C FROM LAKE/SURFACE TO 850 MB. THIS IS SUFFICIENT FOR LAKE INDUCED RAIN SHOWERS OVER THE MOHAWK VALLEY OF NY STATE INTO THE ALBANY/CAPITAL REGION OF NY THIS AFTERNOON. SO NOT OUT OF THE QUESTION FOR A STRAY SPRINKLE ACROS THE BERKSHIRES INTO THE I-91 CORRIDOR OF WESTERN MA. OTHERWISE DRY WEATHER PREVAILS WITH A MIX OF SUN AND CLOUDS... THEN CLEARING TOWARD SUNSET AS DAYTIME HEATING WANES. VERY PLEASANT TEMPS CONTINUE WITH HIGHS IN THE U70S TO L80S /M70S HIGH TERRAIN/ AND DEW PTS IN THE 50S PROVIDING COMFORTABLE HUMIDITY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... TONIGHT... HIGH PRES SLOWLY BUILDS IN FROM THE WEST WITH CLEAR SKIES AND LIGHT WINDS. WITH DRY AIRMASS IN PLACE...GOOD RADIATIONAL COOLING WILL RESULT IN A COOL NIGHT WITH MINS MOSTLY IN THE 50S WITH SOME UPPER 40S POSSIBLE ACROSS PORTIONS OF NW MA. MILDER LOWER 60S URBAN CENTER OF BOS AND OUTER CAPE/ACK. PATCHY LATE NIGHT RADIATION FOG POSSIBLE ACROSS W MA. FRIDAY... A BEAUTIFUL DAY AS HIGH PRES MOVES INTO NEW ENG WITH SUNSHINE AND LIGHT WINDS. MAX TEMPS UPPER 70S TO LOWER 80S WITH SEABREEZES DEVELOPING ALONG THE COAST. DEWPOINTS REMAIN IN THE 50S. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... HIGHLIGHTS... * SURFACE HIGH PRESSURE WILL LINGER OVER THE WEEKEND * ANOMALOUS STRONG RIDGE BUILDS DURING THE WORK WEEK OVERVIEW... 00Z GUIDANCE IS IN GOOD AGREEMENT FOR THIS PORTION OF THE FORECAST. THERE ARE SOME UNCERTAINTY WITH REGARDS TO THE STRENGTH OF A FEW PASSING SHORTWAVES BUT THIS SHOULD NOT IMPACT THE OVERALL TREND IN THE FORECAST. UPPER LEVEL RIDGE WILL BEGIN TO BUILD OVER THE REGION HOWEVER GUIDANCE IS STILL HAVING ISSUES WITH UPPER PLAINS SHORTWAVE. THE EC AMPLIFIES AND TURNS IT INTO A CUT-OFF LOW. FOR THE FIRST HALF OF THE WEEK. THIS WILL DELAY THE HEAT FOR NEXT WEEK BY A DAY OR TWO. WHERE AS THE GFS IS MORE PROGRESSIVE STRETCHING THE WAVE OVER NEW ENGLAND. REGARDLESS BERMUDA HIGH WILL ALLOW FOR AN INCREASE IN MOISTURE AND HEAT OVER THE REGION DURING THIS PERIOD. BEYOND THE PERIOD LARGE SIGNALS THAT THE RIDGE WILL STAY IN PLACE THROUGH THE WEEK AND INTO NEXT WEEKEND. DAILIES... SATURDAY...HIGH CONFIDENCE. HIGH PRESSURE WILL DOMINATE THE REGION HOWEVER THE HEAT AND HUMIDITY WILL BE ON THE INCREASE. MAX TEMPS WILL WARM INTO THE LOW TO MID 80S. THERE IS A LOW PROB OF A SEA BREEZE SO COASTAL LOCATIONS MAY BE WARM AS WELL. OVERNIGHT LOWS WILL DROP INTO THE LOW TO MID 60S. WARMER ON THE SOUTH COASTLINE WHICH MAY LEAD TO FOG DEVELOPMENT. SUNDAY AND BEYOND...LOW CONFIDENCE. GUIDANCE BEGINS TO DIVERGE DURING THIS PERIOD AS THERE ARE SOME UNCERTAINTIES ON THE STRENGTH OF THE SHORTWAVE MOVING THROUGH THE FLOW. AS MENTIONED ABOVE THE DIFFERENCES BETWEEN THE GFS/EC...BOTH THE UKMET AND THE CANADIAN LEAN TOWARDS THE CUT-OFF LOW SCENARIO OF THE EC. THE GEFS ARE ALSO NOT IN FULL SUPPORT OF THE GFS SO DECIDED TO KEEP IT A DRY FORECAST ON SUNDAY. GUIDANCE IS ALSO INDICATING THE POTENTIAL FOR ANOTHER SHOT OF PRECIP AROUND TUES/WED...BUT BECAUSE OF THE TIMING ISSUES AMONGST GUIDANCE DECIDED TO KEEP THE FORECAST DRY FOR NOW. TEMPERATURES WILL BEGIN TO TREND ABOVE AVERAGE STARTING ON SUNDAY AND INTO THE FIRST WEEK OF SCHOOL FOR SOME. BOTH MODELS AND ENSEMBLES ARE HINTING AT ANOMALOUS UPPER LEVEL RIDGE TRYING TO BUILD. DEPENDING ON WHERE THE AXIS OF THE RIDGE SETS UP WE COULD SEE EITHER U80S/L90S OR EVEN MID 90S FOR NEXT WEEK. IF THE AXIS IS WEST OF THE AREA THEN THERE IS THE POTENTIAL FOR POTENTIAL FOR BACK DOOR COLD FRONTS OR EVEN REMNANTS OF MCS ARE POSSIBLE. WILL CONTINUE TO WATCH AS THIS IS AN IMPRESSIVE WARM SIGNAL FROM THE GUIDANCE. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY NIGHT/... THRU 00Z...VFR WITH CIGS BKN035-050. HIGH CONFIDENCE. AFTER 00Z...VFR WITH ISOLATED MVFR LATE IN PATCHY FOG IN INTERIOR VALLEYS. HIGH CONFIDENCE EXCEPT LOWER IN AREAL COVERAGE OF FOG. FRIDAY/FRI NIGHT...HIGH CONFIDENCE. VFR. ISOLATED MVFR POSSIBLE IN LATE NIGHT FOG INTERIOR. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SEA BREEZE LIKELY FRIDAY. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK /SAT THROUGH MONDAY/...HIGH CONFIDENCE. SATURDAY INTO MONDAY...VFR CONDITIONS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY/...HIGH CONFIDENCE. 10 AM UPDATE... ONLY WRINKLE TO THE FORECAST IS A PERSISTENT EAST SWELL OF AROUND 4 FT EVERY 9 SECONDS. THIS COMBINED WITH OFFSHORE WNW WINDS MAY YIELD SOME CHOPPY SEAS AT TIMES FOR THE OCEAN WATERS. THEREFORE HAVE INCREASED SEAS TO ABOUT 4 FT FOR THE WATERS EAST OF CAPE COD AND NANTUCKET. OTHERWISE NO MAJOR CHANGES TO PREVIOUS FORECAST. EARLIER DISCUSSION BELOW. ================================================================== QUIET BOATING WEATHER WITH WINDS AND SEAS BELOW SCA THRESHOLDS. GENERALLY W/NW FLOW BUT WINDS BECOMING LOCALLY ONSHORE OVER NEARSHORE WATERS THIS AFTERNOON AND AGAIN FRI AFTERNOON AS SEABEEZES DEVELOP. OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...HIGH CONFIDENCE. A PERIOD OF QUIET BOATING WEATHER IS EXPECTED THANKS TO BUILDING HIGH PRES. WINDS OUT OF THE SW THROUGH THE PERIOD WITH THE POTENTIAL OF 20 KT GUSTS SUNDAY AFTERNOON. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...KJC/DUNTEN NEAR TERM...NOCERA SHORT TERM...KJC LONG TERM...DUNTEN AVIATION...NOCERA/DUNTEN MARINE...KJC/NOCERA/DUNTEN

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