Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 311958 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 358 PM EDT SUN MAY 31 2015 .SYNOPSIS... A COLD FRONT WILL MOVE SOUTH OFF THE COAST THIS EVENING...THEN STALL SOUTH OF NEW ENGLAND THROUGH TUESDAY AS LOW PRES TRACKS ALONG THE FRONT MONDAY NIGHT INTO TUESDAY. THIS WILL BRING PERIODS OF RAIN TO THE REGION THROUGH TUESDAY. HIGH PRESSURE RETURNS FOR WEDNESDAY AND THURSDAY. ANOTHER COLD FRONT WILL MOVE ACROSS THE REGION FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... SHOWERS AND EMBEDDED TSTMS WITH HEAVY RAINFALL PRODUCING LOCALIZED FLOODING ACROSS NE MA...WITH ADDITIONAL HEAVY RAINFALL MOVING ACROSS N CT AND SW MA. SPC MESOANALYSIS INDICATING SBCAPES 1000-1500 J/KG ACROSS N CT INTO RI AND ADJACENT AREAS OF MA. CLUSTER OF SHOWERS AND THUNDERSTORMS ARE MOVING NE FROM SE NY AND N NJ AND EXPECT SOME OF THIS ACTIVITY TO HOLD TOGETHER AS IT MOVES INTO CT GIVEN SOMEWHAT FAVORABLE INSTABILITY. FOCUS FOR HEAVIEST RAIN MAY END UP CLOSER TO THE CT COAST WHERE BETTER SFC INSTABILITY. HIRES-WRF SHOWING LOCALIZED 3-4" QPF BETWEEN 18-00Z ACROSS PORTIONS OF CT WITH AXIS OF RAINFALL EXTENDING INTO MA AND MUCH OF THIS RAINFALL COULD OCCUR IN A SHORT TIME. AS A RESULT WILL ISSUE A SHORT TERM FLASH FLOOD WATCH THROUGH THIS EVENING FOR N CT AND ADJACENT AREAS OF MA. COLD FRONT MOVING S ACROSS THE REGION AND APPROACHING RI AND SE MA. TEMPS WILL FALL SHARPLY THROUGH THE 60S AND INTO THE UPPER 50S BEHIND THE FRONT WHICH WILL REACH THE S COAST LATE AFTERNOON AND EARLY EVENING. NE WIND GUSTS TO 30 MPH WILL CONTINUE INTO EARLY EVENING ACROSS NE MA. TONIGHT...EXPECT CONVECTION TO WEAKEN THIS EVENING WITH JUST OCCASIONAL LIGHT SHOWERS ACROSS THE REGION...FOCUSED MORE IN THE INTERIOR. LATER TONIGHT...ANOTHER ROUND OF HEAVY RAINFALL WILL LIKELY SET UP ACROSS UPSTATE NY AND VT ASSOCD WITH STRONG LOW LEVEL CONVERGENCE AND FRONTOGENESIS WITH THE 850 MB FRONT TO THE NORTH. HOWEVER...MODELS ARE SHOWING AN AREA OF ENHANCED MID LEVEL OMEGA MOVING INTO SNE LATE TONIGHT WHICH WILL LIKELY BRING ANOTHER PERIOD OF RAIN. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... MONDAY... A BAND OF RAIN WILL LIKELY BE MOVING ACROSS SNE IN THE MORNING ASSOCD WITH AREA OF MID LEVEL LIFT. OTHERWISE...850 MB FRONT WILL REMAIN TO THE NORTH WHILE SFC FRONT IS TO THE S. WITH DECENT E/NE INFLOW AT 950 MB AND SOUTHERLY FLOW AT 850 MB ALONG WITH DEEP MOISTURE IN PLACE WITH PWATS NEAR 1.5" WILL SEE PERIODS OF COOL OVERRUNNING RAIN THROUGH MUCH OF THE DAY WHICH MAY BE LOCALLY HEAVY AT TIMES. ELEVATED INSTABILITY PARAMETERS ARE MARGINAL SO ONLY A LOW PROB FOR AN ISOLD TSTM. A VERY COOL DAY WITH TEMPS AVERAGING 15-20 DEGREES BELOW NORMAL...RANGING FROM NEAR 50 IN THE HIGHER TERRAIN TO MID/UPPER 50S NEAR THE S COAST. IN ADDITION...NE WINDS WILL GUST TO 25-30 MPH ACROSS NE MA. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... BIG PICTURE... CHANGEABLE PATTERN MUCH OF THIS WEEK. AN UPPER TROUGH SLOWLY CROSSES THE NORTHEAST USA EARLY THIS WEEK. AN UPPER RIDGE FROM THE WESTERN USA THEN SHIFTS EAST OVER THE EASTERN USA LATE THIS WEEK. EARLY INDICATIONS FOR THE END OF THE WEEK SHOW POTENTIAL INTERACTION BETWEEN NORTHERN AND SOUTHERN STREAM SHORTWAVES THAT COULD BRING SHOWERS TO NEW ENGLAND TOWARD NEXT WEEKEND. MODELS DIFFER MONDAY-TUESDAY REGARDING PLACEMENT OF FEATURES THAT WOULD FOCUS RAIN/SHOWERS AND BRING HIGHER AMOUNTS. BUT THE LONG RANGE MODELS ARE SIMILAR REGARDING LARGER SCALE FEATURES AND THE GENERAL FLOW OF WEATHER THROUGH THE WEEK. WE USED A BLEND OF THE MODELS TO GENERATE OUR GRID DATA. THE DAILIES... MONDAY NIGHT-TUESDAY... COLD FRONT REMAINS STALLED SOUTH OF NEW ENGLAND. A HIGH PRESSURE BUILDS OVER EASTERN CANADA. THIS WILL BRING AN INCREASING EAST- NORTHEAST WIND ACROSS THE GULF OF MAINE AND INTO SOUTHERN NEW ENGLAND. EXPECTING A COOL MOIST ENVIRONMENT...ESPECIALLY ACROSS EASTERN MA...WITH BELOW NORMAL TEMPERATURES. A LOW PRESSURE MOVES ALONG THE STALLED FRONT TO OUR SOUTH DURING THIS TIME. THIS WILL PROVIDE THE FOCUS FOR WIDESPREAD SHOWERS...AND PERHAPS A THUNDERSTORM OR TWO. THE MAIN CONCERN WILL BE LOCALLY HEAVY RAINFALL. RAINFALL CHANCES BEGIN TO DIMINISH FROM WEST TO EAST TUESDAY AFTERNOON. WEDNESDAY THROUGH FRIDAY...A NORTHERN STREAM SHORTWAVE MOVES EAST OF OUR REGION WEDNESDAY. HIGH PRESSURE BUILDS OVER THE NORTHEAST USA. THIS WILL FAVOR A DRY PERIOD WITH TEMPERATURES TRENDING HIGHER EACH DAY. THE PREVAILING FLOW WEDNESDAY WILL BE NORTHERLY. LIGHTER WINDS WILL FAVOR SEA BREEZES ALONG PORTIONS OF THE COASTLINE THURSDAY AND FRIDAY. SATURDAY...NORTHERN STREAM SHORTWAVE MAY DRIVE A COLD FRONT TOWARD NEW ENGLAND. SHOWERS AHEAD OF THIS FRONT MAY REACH THE WESTERN HALF OF SOUTHERN NEW ENGLAND...BUT LOW CONFIDENCE AT THIS TIME. WE ARE ALSO WATCHING A SOUTHERN STREAM TROUGH...WHICH MAY GENERATE A COASTAL LOW LATE THIS WEEK THAT COULD BRING RAIN UP THE COAST LATE NEXT WEEKEND. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. THROUGH 00Z...MODERATE CONFIDENCE. WIDESPREAD SHOWERS WITH SCT TSTMS WILL CONTINUE TO DEVELOP ACROSS SNE. LOCALLY VERY HEAVY RAINFALL POSSIBLE ACROSS CT. WIDESPREAD MVFR CONDITIONS DEVELOPING WITH LOCALIZED IFR. NE WIND GUSTS TO 25-30 KT DEVELOPING ACROSS NE MA. WIND SHIFT TO N/NE WILL OCCUR LATE AFTERNOON/EARLY EVENING ALONG THE S COAST. TONIGHT AND MONDAY...MODERATE CONFIDENCE. WIDESPREAD MVFR/IFR CONDITIONS. OCCASIONAL SHOWERS AND PERHAPS AN EMBEDDED TSTM WILL PERSIST...WITH GREATEST COVERAGE ACROSS INTERIOR. NE WIND GUSTS TO 25 KT NE MA IN THE EVENING...THEN DIMINISHING OVERNIGHT BUT ANOTHER PULSE TO GUSTS TO 25 KT POSSIBLE MONDAY. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. AREAS OF IFR LIKELY DEVELOP THIS AFTERNOON ALONG WITH NUMEROUS SHOWERS AS WINDS SHIFT TO NE BEHIND THE FRONT. NE WIND GUSTS TO 25 KT DEVELOPING THIS AFTERNOON INTO EARLY EVENING. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...MODERATE CONFIDENCE. MONDAY NIGHT AND TUESDAY...EAST TO NORTHEAST FLOW WITH WINDS ALONG THE MA EAST COAST 10 TO 15 KNOTS WITH GUSTS 15 TO 20 KNOTS POSSIBLE. LIGHTER NORTHEAST WINDS FARTHER INLAND. MVFR/IFR CIGS AND VSBYS... WITH THE GREATEST RISK ACROSS THE COASTAL PLAIN AND EASTERN SLOPES OF THE WORCESTER HILLS. SHOWERS POSSIBLE BOTH DAYS. WEDNESDAY...VFR WITH A NORTH-NORTHWEST WIND. THURSDAY...VFR. LOCAL SEABREEZES POSSIBLE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TODAY THROUGH MONDAY/...HIGH CONFIDENCE. NE GUSTS TO 30 KT WILL CONTINUE INTO THIS EVENING ACROSS NE COASTAL WATERS. EXPECT A BRIEF LULL OVERNIGHT..THEN ANOTHER PULSE OF NE GUSTS TO 30 KT IS EXPECTED DURING MONDAY...AGAIN MAINLY FOCUSED OVER NE COASTAL WATERS. ELSEWHERE...SW WINDS OVER S COASTAL WATERS WILL SHIFT TO NE THIS EVENING AND PERSIST THOUGH MONDAY WITH GUSTS TO 20 KT AT TIMES. SEAS WILL BUILD TO 5-8 FT OVER NE MA COASTAL WATERS. OCCASIONAL SHOWERS AND PATCHY FOG WILL REDUCE VSBYS. OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...MODERATE CONFIDENCE. MONDAY NIGHT-WEDNESDAY NIGHT...SMALL CRAFT ADVISORIES FOR ROUGH SEAS WILL LIKELY BE NEEDED ACROSS THE COASTAL WATERS EAST OF MASSACHUSETTS. SMALL CRAFT ADVISORIES MAY BE NEEDED ACROSS THE SOUTHERN OUTER COASTAL WATERS AS WELL. THURSDAY...NO HEADLINES EXPECTED. HIGH PRESSURE MOVES OVERHEAD. WINDS AND SEAS WILL BE LESS THAN SMALL CRAFT ADVISORY THRESHOLDS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR CTZ002>004. MA...FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR MAZ009-011- 012. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT MONDAY FOR ANZ230. SMALL CRAFT ADVISORY UNTIL 2 AM EDT MONDAY FOR ANZ231. SMALL CRAFT ADVISORY UNTIL 8 PM EDT MONDAY FOR ANZ250-251-254. && $$ SYNOPSIS...KJC/GAF NEAR TERM...KJC SHORT TERM...KJC LONG TERM...GAF AVIATION...KJC/GAF MARINE...KJC/GAF

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