Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 241941 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 341 PM EDT SUN APR 24 2016 .SYNOPSIS...
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HIGH PRESSURE WILL PASS ACROSS THE REGION TONIGHT KEEPING CONDITIONS DRY AND COOL. A FRONT WILL STALL ACROSS THE REGION MONDAY...THEN SLOWLY PUSH SOUTH TUESDAY...BRINGING MUCH NEEDED RAINFALL. DRY BUT COOL CONDITIONS RETURN WITH HIGH PRESSURE FOR MID WEEK. ANOTHER FRONT AND ASSOCIATED LOW PRESSURE MAY APPROACH LATE NEXT WEEK...BRINGING ADDITIONAL RAINFALL.
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&& .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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4 PM UPDATE... SEA BREEZE CONTINUES TO DOMINATE ACROSS THE MASS EAST COAST THIS AFTERNOON KEEPING TEMPS IN THE UPPER 40S TO LOW 50S. ELSEWHERE...TEMPS HAVE RISEN INTO THE LOW 60S ACROSS THE INTERIOR. CLEAR SKIES AND MAINLY LIGHT WINDS HAS RESULTED IN A SPRING DAY IN SOUTHERN NEW ENGLAND. TONIGHT... HIGH PRESSURE OVERHEAD WILL ALLOW FOR LIGHT WINDS AND MOSTLY CLEAR SKIES. ANTICIPATE SURFACE TEMPS TO DROP INTO THE LOW TO MID 30S ESPECIALLY ACROSS AREAS WHERE THE GROWING SEASON HAS BEGUN. THE ONLY ISSUE IS THE HIGH LEVEL CLOUDS ROLLING IN FROM THE EASTERN GREAT LAKES. BELIEVE THE CLOUDS WILL LIMIT RADIATIONAL POTENTIAL ACROSS WESTERN MASS AND CT WHERE AS SOUTHEASTERN MASS COULD TRULY RADIATE OUT ENOUGH FOR FROST DEVELOPMENT. THEREFOR ISSUED A FROST ADV FOR SE MASS FOR TONIGHT. IF CLOUDS HOLD UP HOWEVER THEN FROST ADV MAY NEED TO BE EXPANDED. OTHERWISE ANTICIPATE A DRY FORECAST OVERNIGHT.
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&& .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
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TOMORROW INTO TOMORROW NIGHT... HIGH PRESSURE WILL MOVE OFFSHORE TOMORROW AS A STATIONARY FRONT BEGINS TO PUSH INTO THE REGION. CLOUDS WILL INCREASE THROUGHOUT THE DAY. OVERALL EXPECT DRY WEATHER TO START...WITH SOME SHOWERS MOVING ACROSS NORTHERN MASS LATE TOMORROW AFTERNOON THANKS TO WEAK ISENTROPIC LIFT AND WAA. TEMPERATURES ACROSS THE REGION WILL WARM INTO THE MID 60S WITH THE POTENTIAL FOR A WEAK SEA BREEZE ACROSS THE MASS EAST COAST. UPPER LEVEL SHORTWAVE WILL PUSH THROUGH THE ZONAL FLOW AND MOVE ALONG THE STATIONARY FRONT. GUIDANCE IS STRUGGLING ON EXACT LOCATION OF THE FRONT AND THUS BOTH TEMPERATURES AND WIND FORECASTS HAVE BEEN A STRUGGLE. RIGHT NOW BELIEVE THE FRONT OVER WILL PUSH THROUGH SOUTHERN NEW ENGLAND RESULTING IN SHOWERY WEATHER OVERNIGHT. ADDED THE POTENTIAL FOR THUNDER ACROSS SOUTHERN ZONES AND THE SOUTHERN WATERS AS MODELS SHOW ELEVATED INSTABILITY. TEMPS WILL REMAIN MILD THROUGH THE FIRST HALF OF THE NIGHT BEFORE DROPPING INTO THE 40S TOWARDS DAY BREAK AS THE FRONT PASSES THROUGH.
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&& .LONG TERM /TUESDAY THROUGH SUNDAY/... OVERVIEW... UPPER LEVEL FLOW ACROSS THE LOWER 48 REMAINS PROGRESSIVE WITH BROAD H5 CUTOFF LOW ACROSS THE LOWER ROCKIES WHILE H5 VORTEX CONTINUES TO SPIN ACROSS QUEBEC/LABRADOR EARLY NEXT WEEK KEEPING A CYCLONIC FLOW ACROSS THE REGION. WILL STILL SEE A GENERAL W-NW UPPER LEVEL STEERING CURRENT...THOUGH THIS WILL FLATTEN TO A MORE W FLOW AS THE CUTOFF MEANDERS N OF NEW ENGLAND. FIRST H5 SHORT WAVE IN THE STEERING FLOW APPROACHES DURING TUE...BUT AT THE SURFACE WILL SEE DEVELOPING FRONTAL ZONE AS IT SHIFT SE MON NIGHT. THIS FRONT WILL SLOWLY CROSS THE REGION MON NIGHT/TUE AS IT BECOMES PARALLEL TO THE UPPER FLOW...WHILE WEAK WAVES OF LOW PRES MOVE ALONG IT. THIS WILL ENHANCE THE RAINFALL SOMEWHAT MON NIGHT/TUE. HIGH PRES RIDGING OUT OF CENTRAL CANADA WILL PUSH THE FRONT S OF THE REGION DURING TUE. AS THIS FRONT STALLS ACROSS THE MID ATLC STATES...MID WEEK LOOKS TO BE DRY. ANOTHER SHORT WAVE MOVES ALONG IN THE STEERING FLOW LATE THIS WEEK...WHICH COULD LIFT THE SOUTHERN STALLED FRONT BACK N AS A SURFACE LOW FORMS ALONG IT. TIMING ISSUES CONTINUE ON THE OPERATIONAL MODEL RUNS SO LOWER CONFIDENCE IN THE THU-SAT TIMEFRAME. DETAILS... MONDAY NIGHT-TUESDAY NIGHT... H5 SHORT WAVE APPROACHES IN THE W-NW WIND FLOW ALOFT. COLD FRONT SINKS SLOWLY S OUT OF NY STATE AND NORTHERN NEW ENGLAND. PRECIP DEVELOPS IN INCREASING ISENTROPIC LIFT AS IT SHIFTS SE. SHOWERS WILL MOVE IN DURING MON NIGHT...WITH THE BEST CHANCE FOR SHOWERS DURING TUESDAY AS WEAK LOW PRES WAVE MOVES ALONG THE FRONT. MAY SEE SOME BRIEF HEAVY RAINFALL WITH SOME OF THESE SHOWERS AS PWATS RANGE FROM 1.1 TO 1.25 INCHES...HIGHEST ACROSS S COASTAL AREAS. QPF AMOUNTS RANGING FROM 0.5 TO 0.75 INCHES...BUT COULD SEE A FEW SPOTS THAT RECEIVE A BIT MORE. DID NOTE SOME MARGINAL INSTABILITY PARAMETERS... K INDICES IN THE LOWER 30S S OF THE MASS PIKE OVERNIGHT MON AND SURFACE BASED LI/S NEAR ZERO. AT THIS POINT...DO NOT THINK WILL SEE CONVECTION AS FRONT PUSHES S. SOMETHING TO KEEP AN EYE ON THOUGH. AS COLD FRONT SINKS DOWN THE COAST MON NIGHT INTO TUE MORNING... NOTING A STRONG LOW LEVEL NE JET WORKING DOWN FROM THE MAINE COAST. WINDS UP TO 20-25 KT AT H95 AND H9 WHICH SHOULD GUST AS THE FRONT PASSES E COASTAL AREAS INTO TUE MORNING. WHEN THE FRONT REACHES THE S COAST TUE AFTERNOON...GUSTS UP TO 20-25 KT SHOULD ALSO KICK IN FOR A TIME. H5 SHORT WAVE MOVES ACROSS THE REGION TUE NIGHT. EXPECT PRECIP TO END FAIRLY QUICKLY AFTER THAT...SHOULD BE OFF THE S COAST BY MIDNIGHT OR SO AS DRIER AIR WORKS IN. TEMPS TUE NIGHT MAY BOTTOM OUT CLOSE TO OR JUST BELOW FREEZING ACROSS N CENTRAL AND W MA...RANGING TO AROUND 40 ALONG THE S COAST. WEDNESDAY... HIGH PRES RIDGE BUILDS SE OUT OF CENTRAL CANADA. EXPECT MOSTLY SUNNY SKIES. HOWEVER...EXPECT TEMPS TO ONLY REACH TO THE 50S TO AROUND 60 AS GOOD MIXING BRINGS COOLER AIR DOWN FROM AROUND 850 HPA. THE FRONT THAT PASSED THROUGH TUE STALLS ALONG THE MID ATLC COAST. HOWEVER...WITH THE FAST FLOW ALOFT AND ANOTHER SHORT WAVE IN THE FLOW...MAY START TO SEE MORE CLOUDS RETURN LATE WED NIGHT. TEMPS MAY STILL FALL BACK TO NEAR OR BELOW FREEZING IN THE NORMALLY COLDER INLAND LOCATIONS...RANGING TO THE LOWER 40S ALONG THE S COAST. THURSDAY-FRIDAY... ANOTHER H5 SHORT WAVE MOVES E IN THE FAST FLOW ALOFT...BUT SOME QUESTION ON TIMING IN THE PRECIP DURING THU. THE 00Z GFS AND GGEM IN PRETTY GOOD AGREEMENT IN BRINGING PRECIP IN DURING THE DAY THU...BUT THE 00Z ECMWF IS MUCH SLOWER AND FURTHER S. LEANED TOWARD GFS/GGEM AND ENSEMBLES WHICH WERE IN GENERALLY GOOD AGREEMENT THOUGH HAVE LOWERED CONFIDENCE DURING THIS TIMEFRAME. CARRYING LOW END POPS THU INTO FRIDAY MORNING THEN SHOULD IMPROVE. SATURDAY...ANOTHER CANADIAN HIGH BUILDS ACROSS THE NORTHEAST BRINGING MORE DRY AND SEASONABLE CONDITIONS. TEMPS SHOULD REACH INTO THE LOWER-MID 60S INLAND...BUT WILL HOLD IN THE 50S ALONG THE IMMEDIATE COAST WITH SEA BREEZES. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/...
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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 MONDAY NIGHT/...HIGH CONFIDENCE. TONIGHT...HIGH CONFIDENCE. VFR CONDITIONS. HIGH CLOUDS WILL BEGIN TO INCREASE AFTER 03Z FROM WEST TO EAST. MONDAY...MODERATE TO HIGH CONFIDENCE. VFR CONDITIONS. SEA BREEZE DEVELOPMENT IS POSSIBLE IN THE AFTERNOON FOR MASS EAST COASTLINE. SOME SHOWERY WEATHER WILL MOVE IN NORTH OF THE PIKE DURING THE AFTERNOON. MONDAY NIGHT...MODERATE CONFIDENCE. VFR TO MVFR CONDITIONS OVERNIGHT AS SHOWERS CONTINUE TO SPREAD AND INCREASE ACROSS THE REGION. KBOS TAF...HIGH CONFIDENCE. SEA BREEZE WILL DISSIPATE BY SUNSET. LOW PROB IN SEA BREEZE DEVELOPMENT TOMORROW. KBDL TAF...HIGH CONFIDENCE. LOW PROBABILITY OF MVFR CIGS/VSBYS IN -SHRA LATE MON AFTERNOON. OUTLOOK /TUESDAY THROUGH FRIDAY/...MODERATE CONFIDENCE. MONDAY NIGHT...MVFR TO LOCAL IFR CIGS/VSBYS IN DEVELOPING SHOWERS AND PATCHY FOG. SW WINDS SHIFT TO N ACROSS CENTRAL AND N MA OVERNIGHT WITH GUSTS UP TO AROUND 20 KT ALONG E COASTAL TERMINALS. TUESDAY...MVFR CONDITIONS THROUGH MOST OF THE DAY...WITH PATCHY IFR CIGS/VSBYS IN ANY HEAVIER SHOWERS AND PATCHY FOG. COLD FRONT MOVES S AS WINDS SHIFT TO NE ACROSS N CT/RI/SE MA...GUSTING UP TO 20 KT ALONG S COASTAL TERMINALS AS WELL AS CAPE COD AND THE ISLANDS. CONDITIONS SHOULD IMPROVE TO VFR FROM N-S TUE NIGHT. WEDNESDAY...VFR. THURSDAY...VFR EARLY...THEN AREAS OF MVFR CIGS/VSBYS MOVING IN FROM SW-NE FROM LATE THURSDAY MORNING ONWARD...CONTINUING INTO THU 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 MONDAY NIGHT/...HIGH CONFIDENCE. HIGH PRESSURE OVERHEAD HAS ALLOWED FOR GUSTS BELOW 20 KTS AND SEAS TO CONTINUE TO RELAX TONIGHT. STALLED FRONT OVER NEW ENGLAND TOMORROW WILL ALLOW FOR AN INCREASE SW WIND GRADIENT. SW GUSTS COULD INCREASE TO 20-25 KTS TOMORROW BEFORE THE FRONT MOVES THROUGH TOMORROW NIGHT. OUTLOOK /TUESDAY THROUGH FRIDAY/...MODERATE CONFIDENCE. MONDAY NIGHT...S-SW WINDS TO START...THEN WILL SHIFT TO NE ACROSS THE EASTERN WATERS TO NEAR CAPE COD BAY OVERNIGHT. WINDS WILL GUST UP TO 25 KT AFTER MIDNIGHT. SMALL CRAFTS LIKELY NEEDED. WINDS WILL REMAIN SW GUSTING TO NEAR 20 KT ON THE SOUTHERN WATERS WITH SEAS BUILDING TO AROUND 5 FT. VSBY RESTRICTIONS IN SHOWERS AND PATCHY FOG. TUESDAY...WINDS WILL SHIFT TO N-NW ACROSS THE SOUTHERN WATERS TUE MORNING...GUSTING UP TO 25 KT...WHILE N-NE WINDS REMAIN ON THE EASTERN WATERS. WINDS WILL DIMINISH DURING THE AFTERNOON FROM N-S. SEAS WILL REMAIN AROUND 5 FT ON THE SOUTHERN OPEN WATERS AS WELL AS THE WATERS E OF CAPE COD. VSBY RESTRICTIONS IN SHOWERS AND PATCHY FOG CONTINUE. TUESDAY NIGHT...N-NE WINDS WILL BACK TO NW. GUSTS TO 20 KT TUE EVENING WILL DIMINISH. SEAS REMAIN AT AROUND 5 FT ON THE SOUTHERN WATERS. VSBY RESTRICTIONS TUE NIGHT IN SHOWERS...IMPROVING FROM N-S OVERNIGHT. WEDNESDAY...NW WINDS EARLY WILL BECOMING LIGHT S-SW. SEAS AROUND 5 FT ON THE SOUTHERN WATERS EARLY...THEN SUBSIDE. THURSDAY...LIGHT S WINDS BACK TO E-NE THU NIGHT WITH GUSTS UP TO 20 KT. SEAS UP TO 4 FT ON THE SOUTHERN WATERS. VSBY RESTRICTIONS IN SCATTERED SHOWERS.
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&& .FIRE WEATHER...
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MONDAY...ANTICIPATE MAINLY DRY WEATHER CONDITIONS AS CLOUDS CONTINUE TO THICKEN ACROSS THE REGION. MIN RH VALUES WILL DROP DOWN CLOSE TO 30 PERCENT AS SW WINDS GUSTS WILL INCREASE BETWEEN 10-15 MPH. LOCATIONS ALONG THE CAPE MAY SEE GUSTS NEAR 30 MPH. A FEW SHOWERS ARE POSSIBLE IN THE AFTERNOON NORTH OF THE PIKE. TUESDAY...A SLOW MOVING COLD FRONT WILL BRING ABOUT ONE- HALF TO THREE-QUARTERS OF AN INCH OF RAIN TO THE REGION. WEDNESDAY...HIGH PRESSURE WILL BRING DRY CONDITIONS. MINIMUM RH VALUES OF 25 TO 35 PERCENT EXPECTED AWAY FROM THE COAST...AND 35 TO 50 PERCENT IN COASTAL AREAS. LIGHT NORTHWEST WINDS UNDER 15 MPH BECOME SOUTHWEST BY EVENING.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...FROST ADVISORY FROM 11 PM THIS EVENING TO 8 AM EDT MONDAY FOR MAZ017>021. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ250- 254.
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&& $$ SYNOPSIS...DUNTEN/EVT NEAR TERM...DUNTEN SHORT TERM...DUNTEN LONG TERM...EVT AVIATION...DUNTEN/EVT MARINE...DUNTEN/EVT FIRE WEATHER...STAFF

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