Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 272038 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 438 PM EDT MON JUL 27 2015 .SYNOPSIS... SCATTERED SHOWERS AND THUNDERSTORMS MAINLY ACROSS THE INTERIOR WILL GRADUALLY DIMINISH THIS EVENING WITH THE LOSS OF DAYTIME HEATING. A FAST MOVING DISTURBANCE WILL BRING A ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS TO EASTERN NEW ENGLAND TUESDAY AFTERNOON AND EVENING. A COLD FRONT MAY BRING SCATTERED THUNDERSTORMS LATE THURSDAY AND THURSDAY NIGHT. WARM AND DRY WEATHER IS EXPECTED FRIDAY INTO NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... ***SCATTERED SHOWERS AND THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL MAINLY ACROSS THE INTERIOR SHOULD GRADUALLY DISSIPATE LATER THIS EVENING*** SCATTERED SHOWERS AND THUNDERSTORMS WERE FOCUSED ACROSS INTERIOR SOUTHERN NEW ENGLAND LATE THIS AFTERNOON. WHILE HIT AND MISS ACTIVITY IS POSSIBLE ACROSS MUCH OF THE REGION...HIGHEST RISK FOR TORRENTIAL RAINFALL/LOCALIZED FLOODING WILL BE ACROSS NORTHERN MA. THIS IS WHERE THERE IS SOME SURFACE CONVERGENCE AND ACTIVITY IS MOVING QUITE SLOWLY. A LOCALIZED FLASH FLOOD EVENT OR TWO IS ALSO POSSIBLE WITH POTENTIAL VERY LOCALIZED 3+ INCH PER HOUR RAINFALL RATES. 0 TO 6 KM SHEAR VALUES ARE QUITE WEAK...SO OVERALL SEVERE WEATHER POTENTIAL LOW. NONETHELESS...AN ISOLATED STRONG TO SEVERE THUNDERSTORM OR TWO WILL REMAIN POSSIBLE INTO EARLY THIS EVENING GIVEN MLCAPES OVER 1500 J/KG. DIURNALLY DRIVEN SCATTERED SHOWERS/THUNDERSTORMS SHOULD GRADUALLY COME TO AN END LATER THIS EVENING WITH THE LOSS OF DAYTIME HEATING. OTHERWISE...IT LOOKS LIKE MUCH OF THE OVERNIGHT HOURS WILL BE DRY. WE WILL HAVE TO WATCH FOR THE RISK FOR A FEW SPOT SHOWERS/ISOLATED THUNDERSTORMS DEVELOPING ACROSS EASTERN NEW ENGLAND OVERNIGHT WITH SOME ELEVATED INSTABILITY. LOW LEVEL FORCING DOES NOT SEEM AS STRONG AS LAST NIGHT THOUGH DESPITE FAIRLY HIGH MUCAPES. THEREFORE...JUST WENT WITH LOW POPS OVERNIGHT AS MUCH OF THE REGION SHOULD END UP DRY. THE OTHER CONCERN WILL BE FOR AREAS OF FOG TO DEVELOP OVERNIGHT. WITH RATHER LIGHT WINDS AND WET GROUND...WILL HAVE TO WATCH FOR SOME PATCHY DENSE FOG ESPECIALLY ACROSS THE INTERIOR. THAT WILL DEPEND UPON THE AMOUNT OF BREAKS IN THE SKY COVER OVERNIGHT...BUT SOMETHING LATER SHIFTS WILL HAVE TO WATCH CLOSELY. LOW TEMPS WILL GENERALLY BOTTOM OUT BETWEEN 65 AND 70. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... ***A FEW STRONG TO SEVERE THUNDERSTORMS POSSIBLE TUESDAY AFTERNOON AND EARLY EVENING ALONG WITH LOCALLY HEAVY RAINFALL ACROSS EASTERN MA AND RHODE ISLAND*** TUESDAY... ANY LOW CLOUDS AND FOG PATCHES SHOULD BURN OFF BY LATE MORNING ACROSS THE REGION. OTHERWISE...EXPECT PARTLY SUNNY SKIES TO RESULT IN A VERY WARM TO EVEN BORDERLINE HOT AFTERNOON. HIGH TEMPS WILL TOP OUT MAINLY IN THE UPPER 80S TO NEAR 90. IN ADDITION...IT WILL BE RATHER HUMID OUTSIDE WITH DEWPOINTS IN THE 60S AND RATHER LIGHT WINDS. MAINLY DRY WEATHER EXPECTED TUESDAY MORNING...BUT WE CAN NOT RULE OUT A SPOT SHOWER OR THUNDERSTORM. THE MAIN CONCERN THEN TURNS TO A STRONG PIECE OF SHORTWAVE ENERGY THAT WILL BE DROPPING SOUTH ACROSS THE EASTERN NEW ENGLAND COAST. GIVEN VERY WARM AND HUMID AIRMASS WITH 500 MB TEMPS AROUND -10C...WE SHOULD BE ABLE TO GENERATE MLCAPE VALUES ON THE ORDER OF 1500 J/KG. THE SHORTWAVE COMBINED WITH THE INSTABILITY SHOULD LEAD TO SCATTERED CONVECTION. WHILE AN ISOLATED SHOWER OR THUNDERSTORM IS POSSIBLE ACROSS THE INTERIOR...GREATEST CONCERN IS ACROSS EASTERN MA AND RHODE ISLAND AS THEY WILL BE CLOSER TO THE SHORTWAVE...BUT CAN NOT COMPLETELY RULE OUT CENTRAL MA. WILL RUN WITH SCATTERED SHOWERS/THUNDERSTORMS MAINLY ACROSS THE EASTERN HALF OF THE REGION TUESDAY AFTERNOON AND EARLY EVENING WITH SOME ENHANCED WORDING. AS FOR SEVERE WEATHER POTENTIAL...LOW LEVEL WIND FIELDS ARE RATHER WEAK WHICH WILL BE A LIMITING FACTOR. NONETHELESS...STRONG WINDS ALOFT WILL LIKELY GENERATE 0 TO 6 KM SHEAR VALUES OF 35 TO 45 KNOTS AND THERE IS AN INVERTED V LOOK TO THE SOUNDINGS. THIS MEANS THAT THERE IS THE RISK FOR A FEW STRONG TO SEVERE THUNDERSTORMS...MAINLY ACROSS EASTERN MA AND RHODE ISLAND...BUT CAN NOT RULE OUT CENTRAL MA. LOCALLY DAMAGING WIND GUSTS AND HAIL ARE THE CONCERNS FOR TUESDAY AFTERNOON AND EARLY EVENING. HIGHEST RISK MIGHT BE ALONG THE SEA BREEZE FRONT THAT SETS UP ACROSS EASTERN MA AND RHODE ISLAND AS IT WILL PROVIDE A FOCUS FOR CONVECTION. ALSO...SOMETIMES WE END UP WITH SOME TRAINING ON THESE BOUNDARIES AND THE RISK FOR VERY LOCALIZED FLOODING. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... HIGHLIGHTS... * TRIPLE-H WEATHER WED/THU WITH HIGHS IN 90S. * SCATTERED STORMS THU/THU NIGHT. * DRIER BUT STILL VERY WARM FRI THRU SUN. LARGE SCALE PATTERN FEATURES BUILDING RIDGE OVER NORTHEAST WED/THU WHICH WILL BRING OUR NEXT SHOT OF HEAT AND HUMIDITY. HOWEVER THIS SHOULD BE RELATIVELY SHORT LIVED AS UPPER LOW DIGS ACROSS CANADIAN PRAIRIES AND EVENTUALLY BECOMES CENTERED NEAR HUDSON BAY...RESULTING IN MORE IN WAY OF CYCLONIC FLOW FOR LATER THIS WEEK INTO NEXT WEEKEND. STILL LOOKS SUMMERLIKE BEYOND THU BUT CHANGE IN UPPER AIR PATTERN SHOULD BREAK HUMIDITY AND KEEP TEMPERATURES CLOSER TO AVERAGE FOR LATE JULY. WED INTO THU...HIGH CONFIDENCE. RISING HEIGHTS SHOULD SUPPRESS CONVECTION WED SO AM CONTINUING WITH DRY FORECAST. NAM SUGGESTION OF DEVELOPMENT ALONG SEA BREEZE FRONT IS POSSIBLE BUT IS OUTLIER AT THIS POINT. HIGHS SHOULD TOP OUT IN LOW TO MID 90S AWAY FROM S COAST BUT WITH DEWPOINTS IN MID 60S TO AROUND 70 HEAT INDICES WILL PROBABLY FALL SHORT OF ADVISORY CRITERIA /100F FOR 2+ HOURS/. ANOTHER HOT/HUMID DAY EXPECTED THU BUT HIGHS SHOULD BE SLIGHTLY LOWER THAN WED GIVEN INCREASING CLOUD COVER AHEAD OF COLD FRONT APPROACHING FROM GREAT LAKES. DECENT CAPE/0-6KM SHOULD BE PRESENT ALONG WITH MARGINAL MID LEVEL LAPSE RATES...SO BETTER CHANCE OF SHOWERS/STORMS DURING AFTERNOON AND EVENING AS FRONT PROVIDES FOCUS FOR LIFT. FRI THROUGH SUN...MODERATE CONFIDENCE. HIGH PRESSURE BUILDS ACROSS NORTHEAST AS UPPER FLOW BECOMES MORE CYCLONIC. THIS WILL BRING SOME RELIEF FROM HEAT/HUMIDITY BUT HIGHS SHOULD STILL TOP OUT WELL INTO 80S AWAY FROM S COAST. GOING WITH DRY FORECAST AS ENSEMBLES SHOW FAIRLY LOW PROBABILITIES OF MEASURABLE RAINFALL DURING THIS TIME FRAME. && .AVIATION /20Z MONDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY AFTERNOON/... REST OF THIS AFTERNOON...MODERATE TO HIGH CONFIDENCE. MAINLY VFR EXCEPT LOCALIZED IFR TO LIFR CONDITIONS IN SCATTERED HEAVIER SHOWERS AND THUNDERSTORMS. MAIN FOCUS IS ACROSS INTERIOR SOUTHERN NEW ENGLAND AND ESPECIALLY IN NORTHERN MA. TONIGHT...LOW TO MODERATE CONFIDENCE. DIURNALLY DRIVEN SCATTERED SHOWERS AND THUNDERSTORMS SHOULD DIMINISH THIS EVENING. WHILE DRY WEATHER PROBABLY DOMINATES MOST LOCATIONS OVERNIGHT...A FEW SPOT SHOWERS OR PERHAPS A THUNDERSTORM OR TWO CAN NOT BE RULED OUT. OTHERWISE...MAIN CONCERN OVERNIGHT WILL BE FORMATION OF LOW CLOUDS AND FOG. TIMING UNCERTAIN...BUT WILL HAVE TO WATCH FOR LOCALLY DENSE FOG DEVELOPING OVERNIGHT ESPECIALLY ACROSS THE INTERIOR. TUESDAY...MODERATE TO HIGH CONFIDENCE. ANY LOW CLOUDS AND FOG PATCHES SHOULD IMPROVE TO VFR BY LATE MORNING. MAIN CONCERN IS SCATTERED SHOWERS/THUNDERSTORMS THAT ARE EXPECTED TO DEVELOP GENERALLY ACROSS EASTERN MA/RHODE ISLAND. WHILE ACTIVITY WILL BE HIT AND MISS...THE POTENTIAL IS THERE FOR ISOLATED STRONG TO SEVERE STORMS WITH LOCALLY HEAVY RAINFALL. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. MAINLY VFR THROUGH TONIGHT BUT WILL HAVE TO WATCH FOR A THUNDERSTORM IN THE VICINITY OF THE TERMINAL. HIGHEST RISK IS NORTH OF THE AIRPORT...BUT IT IS POSSIBLE IN BOSTON AS WELL. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. MAINLY VFR THROUGH THIS EVENING BUT WILL HAVE TO WATCH FOR A THUNDERSTORM IN THE VICINITY OF THE TERMINAL. LOW CLOUDS AND SOME FOG MAY DEVELOP LATE TONIGHT. OUTLOOK /TUESDAY NIGHT THROUGH FRIDAY/... TUESDAY NIGHT AND WEDNESDAY...HIGH CONFIDENCE. MVFR/IFR IN SCT SHRA/TSRA TUESDAY EVENING...OTHERWISE VFR. THURSDAY...MODERATE CONFIDENCE. MVFR/IFR IN SCT SHRA/TSRA MAINLY DURING AFTERNOON AND EVENING. FRIDAY...MODERATE CONFIDENCE. VFR. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY AFTERNOON/...HIGH CONFIDENCE. WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS THROUGH TUESDAY AFTERNOON. A FEW SPOT SHOWERS AND PERHAPS A THUNDERSTORM WILL BE POSSIBLE TONIGHT. HOWEVER...A BETTER CHANCE OF A FEW STRONG TO SEVERE THUNDERSTORMS TUESDAY AFTERNOON WHICH MAY RESULT IN BRIEFLY STRONG WIND GUSTS AND HAIL. SPECIAL MARINE WARNINGS MAY BE NEEDED WITH THE HIGHEST RISK ACROSS OUR WATERS ADJACENT TO EASTERN MA. OUTLOOK /TUESDAY NIGHT THROUGH FRIDAY/... TUESDAY NIGHT AND WEDNESDAY...HIGH CONFIDENCE. WINDS AND SEAS REMAIN BELOW SCA. SCA. MAY SEE LEFTOVER SHOWERS/STORMS ON WATERS DURING EVENING. THURSDAY...MODERATE CONFIDENCE. INCREASING S/SW WINDS EXPECTED AHEAD OF COLD FRONT...BUT GUSTS SHOULD PEAK AROUND 20KT MAINLY ON S COASTAL WATERS. BUILDING S SWELL MAY REACH 5 FT ON OUTER WATERS S OF ISLANDS. MAY SEE THUNDERSTORMS LATER IN DAY AND THU EVENING. FRIDAY...MODERATE CONFIDENCE. HIGH PRESSURE BUILDS OVER WATERS. WINDS AND SEAS BELOW SCA. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...FRANK/RLG NEAR TERM...FRANK SHORT TERM...FRANK LONG TERM...RLG AVIATION...FRANK/RLG MARINE...FRANK/RLG

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