Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 071106 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 706 AM EDT TUE JUL 7 2015 .SYNOPSIS... A WARM FRONT WILL WEAKEN AS IT MOVES NORTH ACROSS THE REGION TODAY. A COLD FRONT MOVES ACROSS THE REGION WEDNESDAY BRINGING SHOWERS AND THUNDERSTORMS...SOME WITH HEAVY DOWNPOURS. THE FRONT MOVES SOUTH OF NEW ENGLAND WEDNESDAY NIGHT AND STALLS...ALLOWING ANOTHER ROUND OF SHOWERS AND STORMS THURSDAY. HIGH PRESSURE THEN BUILDS IN WITH FAIR WEATHER FOR FRIDAY AND SATURDAY. ANOTHER WEATHER SYSTEM APPROACHES EARLY NEXT WEEK AND MAY BRING MORE WET WEATHER. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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7 AM UPDATE... MOST OF THE FOG IS LOCATED IN SOUTHWEST CT...BUT LOW CEILINGS EXTEND EAST INTO PARTS OF RI AS WELL. THIS IS PART OF A GENERAL CLOUD COVER THAT HAS BEEN EXPANDING NORTHEAST ACROSS ALL OF OUR AREA. EXPECT THE CLOUDS TO LINGER THIS MORNING AS THE WARM FRONT APPROACHES/MOVES THROUGH. AS WE MOVE INTO THE WARM SECTOR THE CLOUDS SHOULD THIN ENOUGH FOR BREAKS OF SUNSHINE. THE HRRR SHOWS OVER 1000 J/KG GENERATED DURING MID TO LATE AFTEROON...SUFFICIENT TO GENERATE A THUNDERSTORM. NO MAJOR CHANGES TO THE FORECAST AT THIS POINT. PREVIOUS DISCUSSION... AS FOR TODAY...WARM FRONT WILL TEND TO WEAKEN AS IT LIFTS ACROSS THE REGION. LOOKS LIKE THE BEST LIFT WITH THIS FRONT REMAINS ACROSS NY STATE INTO WESTERN VT...THOUGH SCT SHOWERS WILL PUSH ACROSS THE REGION THROUGH EARLY THIS AFTERNOON THEN WILL WEAKEN. BEST SHOT OF PRECIP WILL BE OVER THE CT VALLEY AND E SLOPES OF THE BERKSHIRES...WHERE LIKELY POPS ARE IN PLACE AROUND MIDDAY. MAY NOT SEE PRECIP ACROSS SE MA...CAPE COD AND THE ISLANDS THOUGH PATCHY FOG MAY LINGER. MAY SEE SOME ISOLD INSTABILITY WORK INTO THE REGION...WHICH MAY TRIGGER A THUNDERSTORM OR TWO. ALSO NOTING PWATS AROUND 2 INCHES...SO IF ANY THUNDERSTORMS DO DEVELOP MAY SEE LOCALIZED HEAVY RAINFALL. THE MUGGIES RETURN AS SURGE OF HIGHER DEWPTS WILL PUSH IN THIS AFTERNOON. EXPECT HIGHS MAINLY IN THE LOWER-MID 80S AWAY FROM THE S COAST...WHERE READINGS WILL HOLD IN THE 70S WITH THE ONSHORE WIND.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... TONIGHT... EXPECT COLD FRONT TO SLOWLY APPROACH THE REGION OUT OF NY STATE. SHOULD REMAIN DRY...EXCEPT FOR SOME WIDELY SCT SHOWERS POSSIBLE ACROSS NW MA EARLY TONIGHT. HAVE INCREASED CHANCE POPS AFTER MIDNIGHT FROM W-E. SOME SHORT RANGE MODEL DIFFERENCES IN HANDLING MOISTURE WITH AND AHEAD OF THE FRONT...THOUGH SOUPY AIRMASS REMAINS IN PLACE SO COULD SEE SCT PRECIP. ALSO HELD OFF MENTION OF THUNDER AS BEST INSTABILITY REMAINS CLOSER TO THE FRONT. WILL ALSO SEE FOG RETURN ESPECIALLY ACROSS S COASTAL AREAS ESPECIALLY THE CAPE AND ISLANDS AS TEMPS ONLY DROP TO AROUND 70. WEDNESDAY... COLD FRONT SLOWLY CROSSES THE REGION. BEST INSTABILITY ALSO MOVES IN BY MIDDAY...WITH K INDICES IN THE LOW-MID 30S...CAPES RISING TO 1000-1200 J/KG BY MIDDAY ESPECIALLY ACROSS CENTRAL AND EASTERN AREAS ALONG WITH TQ VALUES IN THE UPPER TEENS SIGNALING SOME ELEVATED CONVECTION.BIG CONCERN THOUGH IS THE INCREASING PWATS... UP TO 2 TO 2.2 INCHES WITH GOOD LOW LEVEL MOISTURE CONVERGENCE. COULD SEE A FEW STRONG STORMS THOUGH CHANCE LIMITED WITH CLOUD COVER...BUT BETTER SHOT FOR HEAVY DOWNPOURS WHICH COULD CAUSE LOCALIZED URBAN AND POOR DRAINAGE FLOODING. EXPECT THREAT FOR THUNDER TO WIND DOWN ACROSS ROUTE 2 AREA AROUND OR AFTER 18Z...WITH BEST SHOT FOR PRECIP SHIFTING TO NEAR AND S OF THE MASS PIKE THROUGH THE REMAINDER OF THE DAY. FRONT LOOKS TO BE SLOWING AS IT MOVES S DURING THE AFTERNOON AS WELL. MAY SEE IMPULSE MOVE ALONG THE FRONT WHICH COULD CAUSE TRAINING OF SHOWERS AND CONVECTION...ANOTHER PROBLEM FOR POSSIBLE FLOODING. EXPECT A WARM AND MUGGY DAY WITH DEWPTS IN THE MID 60S TO NEAR 70 AS HIGHS REACH INTO THE MID AND UPPER 80S ACROSS THE LOWER CT VALLEY AND INTERIOR E MA...EVEN REACHING THE LOWER 80S ON THE CAPE. TEMPS LOOK TO HOLD IN THE UPPER 70S ON THE ISLANDS. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... BIG PICTURE... UPPER HIGH PRESSURE REMAINS IN CONTROL OVER THE ATLANTIC COAST WHILE LOW PRESSURE DIGS OVER THE WESTERN USA. JET FLOW FROM WESTERN CANADA RIDES ALONG THE US/CANADIAN BORDER. THE RIDGE SHIFTS TO THE MIDWEST AND PLAINS OVER THE WEEKEND MAKING ROOM FOR A TROUGH TO DIG OVER THE CANADIAN MARITIMES. UPPER HEIGHTS REMAIN AT OR ABOVE SEASONAL NORMALS THROUGH THE PERIOD. THIS SUGGESTS NORMAL SUMMER TEMPERATURES...ALTHOUGH DAYTIME HIGHS WILL OF COURSE BE HELD BACK ON DAYS OF HEAVY SKY COVER OR STRONG EAST FLOW. THE DAILIES... WEDNESDAY NIGHT-THURSDAY...MODERATE CONFIDENCE. COLD FRONT IN SOUTHEAST NEW ENGLAND DURING THE EVENING MOVES OFFSHORE BEFORE MIDNIGHT. THE FRONT THEN BECOMES ALIGNED WITH THE UPPER FLOW AND STALLS SOUTH OF THE REGION. SHORTWAVE IN THE UPPER FLOW MOVES THROUGH DURING THURSDAY...GENERATING A WAVE ALONG THE FRONT AND MAINTAINING A RISK OF SHOWERS THURSDAY. THE BEST CHANCE WILL BE SOUTH OF THE MASS PIKE NEAREST THE WAVE AND THE FRONT. PRECIPITABLE WATER VALUES REMAIN HIGH NEAR THE SOUTH COAST...SO LOCALLY HEAVY DOWNPOURS WILL CONTINUE TO BE A CONCERN IN SOUTHERN AREAS. CLOUDS AND A LIGHT EAST FLOW SHOULD KEEP DAYTIME TEMPS IN THE 70S. FRIDAY-SATURDAY...MODERATE TO HIGH CONFIDENCE. HIGH PRESSURE BUILDS OVER THE REGION WITH CLEARING SKIES AND LIGHT WINDS. MIXING SHOULD REACH TO AT LEAST 850 MB AND POSSIBLY TO 800 MB. TEMPS AT THESE LEVELS WOULD SUPPORT MAX TEMPS OF 80-85 FRIDAY AND MID 80S SATURDAY. DEW POINTS 55 TO 65 AND LIGHT WINDS SUGGEST MIN TEMPS IN THE SAME RANGE AS WELL AS PATCHY FOG. SUNDAY-MONDAY...LOW CONFIDENCE. CHANGES IN THE OPERATIONAL MODEL SOLUTIONS REGARDING MOISTURE IN THE VERTICAL ACTS TO SUPPRESS PCPN IN SOUTHERN NEW ENGLAND DURING THIS PERIOD. MEANWHILE A SHORTWAVE SWINGS ACROSS NORTHERN NEW ENGLAND INTO THE MARITIMES...PUSHING A COLD FRONT THROUGH OUR AREA. IT IS HARD TO TOTALLY KILL OFF POPS WHILE SUCH A MECHANISM IS IN PLACE. WE WILL MAINTAIN CHANCE POPS FOR THE MOMENT AND AWAIT FUTURE MODEL RUNS. && .AVIATION /12Z 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/... TODAY...MODERATE TO HIGH CONFIDENCE. MAINLY VFR VSBYS DURING THE MORNING...THEN PATCHY MVFR CIGS MAINLY ALONG THE S COAST. BRIEF MVFR CONDITIONS IN SCT SHOWERS. LOW PROB OF ISOLD AFTERNOON THUNDERSTORMS. S-SE WIND GUSTS UP TO 20-25 KT ALONG COAST THIS AFTERNOON...HIGHEST ALONG E COAST. TONIGHT...MODERATE CONFIDENCE. CONDITIONS LOWER TO MAINLY MVFR BY 04Z-05Z IN PATCHY FOG. CHANCE OF SHOWERS ACROSS W MA/N CENTRAL CT THROUGH MOST OF THE NIGHT WITH CHANCE OF ISOLD THUNDERSTORMS THROUGH 04Z. MAY SEE IFR VSBYS ACROSS E MA/RI/N CT AFTER 06Z-07Z. WEDNESDAY...MODERATE CONFIDENCE. EXPECT MVFR TO LOCAL IFR CONDITIONS IN SCT SHOWERS AS COLD FRONT SLOWLY CROSSES THE REGION. CHANCE OF AFTERNOON THUNDERSTORMS... SOME WITH HEAVY DOWNPOURS. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... WEDNESDAY NIGHT-THURSDAY...MODERATE CONFIDENCE. A COLD FRONT OVER SOUTHEAST MASS/RI IN THE EVENING MOVES OFFSHORE WITH WINDS BECOMING NORTH OVERNIGHT AND NORTHEAST THURSDAY BUT WITH SPEEDS BELOW 15 KNOTS. SHOWERS MOVING UP THE FRONT THURSDAY WILL BRING AREAS OF MVFR CIGS/VSBYS WITH THE BEST CHANCE IN CT-RI AND SOUTHEAST MASS. FRIDAY-SATURDAY...MODERATE-HIGH CONFIDENCE. HIGH PRESSURE BRINGS CLEARING SKIES. VFR. AREAS OF IFR POSSIBLE IN EARLY MORNING FOG.
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&& .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. TODAY...EXPECT LIGHT/VRBL WINDS BECOMING S-SE BY MIDDAY...THEN SHIFT TO S AS WARM FRONT LIFTS N. MAY SEE GUSTS UP TO 20-25 KT ACROSS THE NEAR SHORE WATERS...HIGHEST ON THE EASTERN WATERS. SEAS BUILD UP TO 4 FT...MAINLY ACROSS THE SOUTHERN WATERS. TONIGHT...MAY SEE LEFTOVER 20-25 KT GUSTS THIS EVENING THEN WILL DIMINISH. PATCHY FOG DEVELOPS WITH REDUCED VSBYS...BELOW 3 MILES AFTER MIDNIGHT. WEDNESDAY...SW WINDS WILL INCREASE...WITH GUSTS UP TO 20 KT ON THE SOUTHERN OUTER WATERS. EXPECT SEAS TO REMAIN BELOW 5 FT...THOUGH MAY BRIEFLY REACH 5 FT AT TIMES. CHANCE OF SHOWERS/THUNDERSTORMS SOME WITH HEAVY RAINFALL. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... WINDS AND SEAS REMAIN BELOW SMALL CRAFT THRESHOLDS THROUGH THE PERIOD. A COLD FRONT MOVES OFFSHORE WEDNESDAY NIGHT AND STALLS OVER THE SOUTHERN WATERS. A DISTURBANCE MOVING ALONG THE FRONT WILL BRING SHOWERS AND SCATTERED TSTMS WEDNESDAY NIGHT/THURSDAY WITH REDUCED VSBYS IN ANY HEAVY DOWNPOURS. HIGH PRESSURE BRINGS FAIR WEATHER FRIDAY AND SATURDAY. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 10 PM EDT THIS EVENING FOR ANZ250. SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM EDT THIS EVENING FOR ANZ231-251. SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 PM EDT THIS EVENING FOR ANZ230. && $$ SYNOPSIS...WTB/EVT NEAR TERM...WTB/EVT SHORT TERM... LONG TERM...WTB/EVT AVIATION...WTB/EVT MARINE...WTB/EVT

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