Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 010757 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 357 AM EDT TUE SEP 1 2015 .SYNOPSIS...
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AFTER A WEAK COLD FRONT MOVES INLAND TODAY...HIGH PRESSURE ONCE AGAIN REGAINS CONTROL INTO WEDNESDAY. HEAT RETURNS WEDNESDAY INTO THURSDAY. ANOTHER COLD FRONT SHOULD BRING SCATTERED SHOWERS AND THUNDERSTORMS THURSDAY. THEN NOT AS WARM AND NOTICEABLY LESS HUMID WEATHER FOR FRIDAY INTO SAT MORNING. A WARMING TREND FOLLOWS FOR THE HOLIDAY WEEKEND WITH TEMPERATURES WELL INTO THE 80S TO PERHAPS NEAR 90 BY SUNDAY AND MONDAY ALONG WITH DRY WEATHER.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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VERY SUBTLE BACKDOOR COLD FRONT IS CURRENTLY SLIDING IN FROM THE NE EARLY THIS MORNING. SO SUBTLE IN FACT IT/S BARELY VISIBLE IN THERMAL FIELDS AND REQUIRES THE MASS FIELDS TO FULL APPRECIATE. AS SUCH...THE LACK OF ANY INSTABILITY/MOISTURE HAS ALLOWED MAINLY CLEAR SKIES TO DOMINATE ACROSS THE REGION. THIS WILL BE THE EXPECTATION WITH SUNRISE THIS MORNING AS WELL...PLENTY OF SUNSHINE OUTSIDE OF A FEW HIGH CI. THE COOLER AIRMASS ASSOCIATED WITH THE FRONT...COMBINED WITH ONSHORE FLOW ACROSS MAINLY ERN MA/RI WILL YIELD COOLER HIGHS TODAY THAN PREVIOUS DAYS. TEMPS WILL RANGE FROM THE MID 80S IN THE CT VALLEY...TO THE UPPER 70S NEAR THE E COAST. PLENTY OF DRY AIR SHOULD KEEP THE MOSTLY SUNNY SKIES IN PLACE AS STRONG SUBSIDENCE INVERSION BEGINS TO BUILD OVER THROUGH THE AFTERNOON AND EVENING HOURS.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
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TONIGHT... SUBSIDENCE INVERSION CONTINUES TO BUILD AS HIGH PRES REGAINS CONTROL ACROSS THE REGION. THIS WILL ALLOW MID LVL TEMPS /PARTICULARLY AROUND H85/ TO APPROACH +20C. ANY LOW LVL MOISTURE IS LIKELY TO BECOME TRAPPED AND WITH INCREASING DWPTS...LIGHT FLOW AND MAINLY CLEAR SKIES COULD SEE MORE WIDESPREAD FOG ESPECIALLY ACROSS WRN MA/CT DURING THE EARLY MORNING HOURS. WED... NEAR +20C H85 TEMPS AND PLENTY OF SUNSHINE WILL LEAD TO ONE OF THE HOTTEST DAYS YET THIS WEEK. EXPECT WIDESPREAD LOW 90S...WITH UPPER 80S ELSEWHERE. SEA BREEZE KEEP S NEAR SHORE LOCATIONS A BIT COOLER. NOTING A SLIGHT SLACKENING OF MASS FIELDS AS HIGH PRES SHIFTS N...BUT BUFKIT IS VERY DRY ALOFT. WHILE THE SUPPORTS STEEP MID LVL LAPSE RATES AND EVEN A VERY SLIM CORRIDOR OF CAPE ALOFT...THE DRY AIR AND SUBSIDENCE SHOULD CAP ANY DAYTIME/EVENING SHOWERS/STORMS. MAINLY DRY FORECAST.
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&& .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
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HIGHLIGHTS... * SCATTERED T-STORMS THU...OTHERWISE DRY WEATHER PREVAILS * COOLER AND LESS HUMID THU NIGHT/FRI INTO SAT MORNING * DRY WITH A GRADUAL WARMING TREND FOR THE HOLIDAY WEEKEND WED NIGHT...QUIET/DRY WEATHER WITH RIDGING HOLDING ON AND ASSOCIATED DEEP LAYER DRY AIR OVER THE REGION. IT WILL BE A WARM NIGHT AFTER DAYTIME TEMPS WED PEAK IN THE U80S AND L90S. THIS COMBINED WITH DEW PTS REMAINING IN THE 60S WILL RESULT IN MINS ONLY FALLING TO 65 TO 70...WITH LOW 70S IN THE URBAN AREAS. THURSDAY...BEST CHANCE FOR A BRIEF END TO OUR DRY WEATHER AS MID LEVEL TROUGH MOVES ACROSS THE MARITIMES AND DRAGS A COLD FRONT ACROSS SNE. BEST SYNOPTIC SCALE FORCING IS DISPLACED WELL EAST OF NEW ENGLAND...HOWEVER SHALLOW LIFT/CONVERGENCE ASSOCIATED WITH THE FRONT WILL COMBINE WITH MODEST DEEP LAYER MOISTURE TO YIELD A RISK FOR SCATTERED SHOWERS/T-STORMS. MODERATE INSTABILITY WITH PROJECTED CAPES ON THE ORDER OF 1000-2000J/KG. HOWEVER LIMITING FACTOR IS LACK OF DEEP LAYER SHEAR. THUS CONVECTION WILL BE DIFFICULT TO SUSTAIN AND THIS WILL REDUCE THE THREAT OF STRONG TO SEVERE STORMS. HOWEVER IF CAPES CAN GROW TO 2000 J/KG OR GREATER INSTABILITY MAY COMPENSATE FOR LACK OF DEEP LAYER SHEAR WITH THE RISK OF A FEW STORMS BECOMING STRONG TO PERHAPS SEVERE. ALTHOUGH WEAK WIND FIELDS ALOFT SUGGEST ONLY A LOW RISK OF STRONG STORMS. PWATS CLIMB TO ABOUT +1 STD DEVIATIONS GREATER THAN CLIMO. THIS COMBINED WITH WEAK WIND FIELDS ALOFT MAY POSE A LOW RISK OF SLOW MOVING STORMS AND ASSOCIATED FLOOD THREAT. OTHERWISE EXPECT ANOTHER VERY WARM AND HUMID DAY WITH HIGHS 85 TO 90. SO BY NO MEANS A WASHOUT OUT...A TYPICAL LATE SUMMER DAY WITH VERY WARM TEMPS AND A THREAT OF SCT AFTN/EVENING T-STORMS. THURSDAY NIGHT/FRIDAY/FRI NIGHT...NOTICEABLE AIRMASS CHANGE WITH COOLER AND LESS HUMID AIRMASS ADVECTS INTO THE REGION THU NIGHT AS 1027 MB CANADIAN HIGH BUILDS SOUTHWARD THRU QUEBEC. IN FACT COULD SEE NE WINDS GUSTS UP TO 20-25 MPH OVER SE MA FRI MORNING! ALTHOUGH THIS BACKDOOR COLD FRONT WON/T HAVE THE SAME PUNCH/COOL DOWN AS AN EARLY SUMMER/LATE SPRING EVENT AS SSTS IN GULF OF ME AND EASTERN MA WATERS ARE RUNNING 65-70! NEVERTHELESS REFRESHING CHANGE FRI INTO SAT AM AS 1027 HIGH BUILDS OVER THE AREA WITH DEW PTS IN THE 50S. THUS BREEZY NE WINDS FRI AM WILL SLACKEN IN THE AFTN. THIS WILL SET THE STAGE FOR A COOL FRI NIGHT WITH MINS EARLY SAT MORNING IN THE 50S REGIONWIDE...EXCEPT NEAR 60 IN THE URBAN AREAS AND ALONG THE COAST. HOLIDAY WEEKEND...AFTER A COOL/COMFORTABLE SAT MORNING A GRADUAL WARMING TREND AS MID LEVEL RIDGE BUILDS OVER THE AREA...RESULTING IN SURFACE RIDGE SLIDING SOUTH OF NEW ENGLAND YIELDING A WESTERLY SURFACE FLOW. THIS WEST WIND SHOULD KEEP HUMIDITY IN CHECK WITH DEW PTS LIKELY REMAINING IN THE 50S AND ONLY CREEPING UPWARD TOWARD 60 GIVEN DOWNSLOPE COMPONENT OF SFC WND. THUS EARLY INDICATIONS SUGGEST A DRY HOLIDAY WEEKEND WITH A GRADUAL WARMING TREND.
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&& .AVIATION /07Z 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/... THROUGH TODAY...HIGH CONFIDENCE. VFR. SEA BREEZES ASSISTED BY WEAK E-NE FLOW DEVELOPING ACROSS E MA. TONIGHT...MODERATE CONFIDENCE. MAINLY VFR THROUGH THE EVENING...HOWEVER AFTER MIDNIGHT SOME FOG MAY DEVELOP MAINLY AT TERMINALS WITHIN AND W OF THE CT VALLEY. THIS IS WHERE THE MODERATE CONFIDENCE COMES IN. WEDNESDAY...HIGH CONFIDENCE. VFR AFTER ANY FOG BURNS OFF. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SEA BREEZE TIMING 13-15Z THIS MORNING. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/...HIGH CONFIDENCE. MAINLY VFR CONDITIONS THROUGHOUT THE PERIOD. LOW PROBABILITY OF BRIEF MVFR CONDITIONS IN SCT SHRA/TSRA THU. ALSO...IFR VSBYS POSSIBLE IN PATCHY FOG EACH NIGHT.
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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 WEDNESDAY/...HIGH CONFIDENCE. SEAS WILL GRADUALLY RECEDE THROUGH THE DAY TODAY...SUCH THAT THEY DROP MAINLY BELOW 3 FT ACROSS ALL WATERS LATE TONIGHT INTO WED. WEAK FLOW THROUGH THE PERIOD. THEREFORE...MAINLY QUIET BOATING WEATHER PREVAILS THROUGH WED. OUTLOOK /WEDNESDAY THROUGH SATURDAY/...HIGH CONFIDENCE. FAIRLY TRANQUIL BOATING WEATHER THIS PERIOD. THE EXCEPTION WILL BE LATE THU NIGHT INTO FRI MORNING WHEN 1027 MB HIGH OVER QUEBEC YIELDS A STIFF NE WIND OF 15 TO 20 KT WITH GUSTS UP TO 25 KT POSSIBLE. WINDS DROP OFF LATE FRI HOWEVER LOW PRES MAY DEVELOP WELL SE OF NOVA SCOTIA NEXT WEEKEND. THIS MAY RESULT IN EASTERLY SWELLS IMPACTING THE EASTERN MA WATERS. DRY WEATHER MUCH OF THE PERIOD WITH THE EXCEPTION OF SCATTERED T-STORMS POSSIBLE THU AFTN AND EVENING.
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&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...NOCERA/DOODY NEAR TERM...DOODY SHORT TERM...DOODY LONG TERM...NOCERA AVIATION...NOCERA/DOODY MARINE...NOCERA/DOODY

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