Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 280540 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 140 AM EDT TUE JUL 28 2015 .SYNOPSIS... A FAST MOVING DISTURBANCE WILL BRING A ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS TO EASTERN NEW ENGLAND TUESDAY AFTERNOON AND EVENING. HOT AND HUMID TUESDAY THROUGH THURSDAY. 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 THIS MORNING/... 2 AM UPDATE... DEWPOINTS CONTINUE TO RISE OVERNIGHT KEEPING TEMPS NEAR STEADY. IN FACT MOST PLACES WILL REMAIN IN THE LOW 70S TO UPPER 60S OVERNIGHT. SURFACE MOISTURE CONTINUE TO INCREASE ALLOWING FOR A DESCENT INVERSION OVER THE AREA. SEVERAL PLACES HAVE ALREADY DROPPED IN VSBYS...ORE...CEF AND BAF. ANTICIPATE VSBYS TO BE AROUND 1SM DURING THE MORNING COMMUTE SO ENCOURAGE DRIVERS TO USE CAUTION. OTHERWISE PATCHY FOG AND STRATUS IS STARTING TO DEVELOP ACROSS THE SOUTH COAST OF RI AND SHOULD SPREAD INTO MASS OVERNIGHT. ASIDE FROM FOG...THE OTHER FOCUS IS ON THE CONVECTION ACROSS VT. HI-RES GUIDANCE SHOWS THESE STORM DISSIPATING AS IT MOVES TOWARDS SOUTHERN NEW ENGLAND...BUT WITH APPROACHING SHORTWAVE AND LINGERING INSTABILITY CANNOT RULE OUT A FEW OF THESE SHOWERS MOVING INTO NE MASS. WILL CONTINUE TO MONITOR OVER THE NEXT FEW HOURS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... ***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 /WEDNESDAY 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. OVERALL...GOOD AGREEMENT AMONGST THE MODELS ON THE SYNOPTIC PATTERN. UPPER RIDGE OVER THE GREAT LAKES AND OHIO VALLEY SLOWLY WEAKENS AS ITS PUSHED EASTWARD BY AN UPPER LOW TRAVELING ACROSS THE CANADIAN PRAIRIE. THIS LOW WILL BECOME STATIONARY OVER HUDSON BAY AND REMAIN THERE THROUGH MUCH OF THE FORECAST PERIOD WITH THE SURFACE REFLECTION PARKED JUST BELOW IN ABOUT THE SAME LOCATION. THIS WILL KEEP SOUTHERN NEW ENGLAND IN SOUTHWESTERLY TO WESTERLY SURFACE WINDS BRINGING HOT AND HUMID AIR INTO THE REGION. TUESDAY NIGHT...COULD SEE SOME LINGERING SHOWERS AND THUNDERSTORMS INTO THE EARLY PART OF THE NIGHT AS A FRONT EXTENDING FROM LOW PRESSURE IN THE MARITIMES MOVES OFFSHORE. OTHERWISE...A FAIRLY HUMID NIGHT WITH WARM TEMPERATURES EXPECTED TO REMAIN IN THE UPPER 60S TO LOWER 70S. WEDNESDAY...ANOTHER HOT...HUMID...AND HAZY DAY EXPECTED AS THE UPPER LEVEL RIDGE MOVES OVER SOUTHERN NEW ENGLAND. HIGH TEMPERATURES ARE EXPECTED TO BE IN THE LOWER 90S FOR MOST LOCATIONS. WITH DEWPOINTS REMAINING IN THE UPPER 60S TO LOWER 70S...HEAT INDICES WILL EASILY BE IN THE UPPER 90S TO NEAR 100. MAIN QUESTION FOR WEDNESDAY WILL BE WHETHER OR NOT THEY COULD REACH 100 AND HEAT ADVISORIES BE NEEDED. THURSDAY...A WEAK FRONT EXTENDING FROM THE LOW PRESSURE IN HUDSON BAY WILL SWING THROUGH SOUTHERN NEW ENGLAND ALLOWING FOR A POTENTIAL OF SHOWERS AND THUNDERSTORMS LATE IN THE DAY INTO THURSDAY NIGHT. DECENT INSTABILITY...0-6KM SHEAR...AND MARGINAL MID LEVEL LAPSE RATES WILL ALLOW A FEW OF THESE STORMS TO BECOME STRONG. FRIDAY THROUGH SUNDAY...WITH THE SYNOPTIC SCALE PATTERN FAIRLY STATIONARY...EXPECT HOT AND SOMEWHAT HUMID WEATHER TO CONTINUE THROUGH THE WEEKEND. TEMPERATURES WILL BE IN THE UPPER 80S TO LOWER 90S. MONDAY...ANOTHER FRONTAL SYSTEM MAY BRING SHOWERS AND THUNDERSTORMS TO THE REGION. && .AVIATION /06Z TUESDAY 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/... BEFORE 00Z...LOW TO MODERATE CONFIDENCE. DRY WEATHER DOMINATES OVERNIGHT...A FEW SPOT SHOWERS ARE POSSIBLE IN NE MASS AROUND DAYBREAK. OTHERWISE...LOW CLOUDS AND FOG HAVE STARTED TO DEVELOP ACROSS SOUTH COAST AND CT VALLEY. LOCALLY DENSE FOG IS POSSIBLE DROPPING TERMINALS TO LIFR. TODAY...MODERATE TO HIGH CONFIDENCE. ANY LOW CLOUDS AND FOG PATCHES SHOULD IMPROVE TO VFR BY LATE MORNING. SCATTERED SHOWERS/THUNDERSTORMS WILL 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. TONIGHT...MODERATE CONFIDENCE. VFR FOR MOST SITES. CANNOT RULE OUT IFR IN STRATUS AND FOG ACROSS SE MASS INCLUDING THE CAPE AND ISLANDS. WEDNESDAY...HIGH CONFIDENCE. VFR WITH DIURNAL CU DEVELOPING AROUND 5K. A SPOT SHOWER IS POSSIBLE. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SEA BREEZE AROUND 14-16Z. LOW CONFIDENCE ON STRONG/SEVERE THUNDERSTORM HITTING THE TERMINAL. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. LOW CLOUDS AND SOME FOG MAY DEVELOP EARLY THIS MORNING. OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/... THURSDAY...MODERATE CONFIDENCE. MAINLY VFR EXCEPT IN SCT -SHRA/TSRA. FRIDAY THROUGH SATURDAY...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 SATURDAY/... HIGH CONFIDENCE. QUIET BOATING WEATHER IS EXPECTED THROUGH THE PERIOD. THERE MAY BE SHOWERS AND THUNDERSTORMS OVER THE WATERS TUESDAY NIGHT AND AGAIN THURSDAY AND THURSDAY NIGHT. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...FRANK/RLG NEAR TERM...DUNTEN SHORT TERM...FRANK LONG TERM...RLG AVIATION...DUNTEN/RLG MARINE...FRANK/RLG

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