Area Forecast Discussion
Issued by NWS Boston, MA

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620 FXUS61 KBOX 031914 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 315 PM EDT TUE MAY 3 2016 .SYNOPSIS... CLOUDY...DREARY AND COOL WEATHER CONTINUES THROUGH FRIDAY WITH PERIODS OF RAIN AS WEAK WAVES OF LOW PRESSURE PASS SOUTH OF OUR REGION. SOME SHOWERS ARE STILL POSSIBLE AT TIMES THIS WEEKEND...BUT TEMPERATURES WILL BEGIN TO MODERATE. SIGNIFICANT IMPROVEMENT WILL LIKELY OCCUR EARLY NEXT WEEK WITH MUCH MILDER TEMPERATURES. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... SCATTERED SHOWERS WILL COME TO AN END EARLY THIS EVENING AS DRIER MID LEVEL AIR WORKS INTO THE REGION. STILL AN ABUNDANCE OF LOW LEVEL MOISTURE...SO CLOUDS WILL PERSIST OVERNIGHT AND CAN NOT RULE OUT A SPOT SHOWER OR TWO AND PERHAPS SOME PATCHY DRIZZLE. LOW TEMPS WILL BE IN THE 40S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... ***NEXT BAND OF STEADY RAIN AFFECTS MOST OF THE REGION LATE WEDNESDAY AFTERNOON/EVENING PARTICULARLY EASTERN MA/RI*** WEDNESDAY AND WEDNESDAY NIGHT... MOIST EAST TO NORTHEAST FLOW WILL DOMINATE INTO EARLY WEDNESDAY AFTERNOON WITH LOW CLOUDS TRAPPED BENEATH THE SUBSIDENCE INVERSION. FORCING WILL BE LIMITED THROUGH THAT TIME...BUT GIVEN THE DEEP LOW LEVEL MOISTURE A FEW SHOWERS ARE EXPECTED. HIGH TEMPS WILL MAINLY BE IN THE 50S. PORTIONS OF THE EASTERN MA COAST MAY STRUGGLE TO GET PASSED THE 50 DEGREE MARK. THINGS BECOME MORE INTERESTING LATE WEDNESDAY AFTERNOON AND EVENING. CLOSED UPPER LEVEL LOW PRESSURE DIGGING ACROSS THE OHIO VALLEY WILL BACK THE MID LEVEL FLOW AND INCREASE THE FORCING FOR ASCENT. STEADY RAIN SHOULD OVERSPREAD MOST OF THE REGION LATE WEDNESDAY AFTERNOON/EARLY EVENING. APPEARS MOST OF THE GUIDANCE INDICATES BETTER MID LEVEL FORCING/LIFT ACROSS EASTERN MA/RI...SO EXPECT THE HIGHER RAINFALL TOTALS IN THESE LOCATIONS. THERE IS SOME MARGINAL ELEVATED INSTABILITY...SO A LOW RISK FOR A FEW EMBEDDED THUNDERSTORMS EXISTS ACROSS THE SOUTHEAST NEW ENGLAND COAST WEDNESDAY EVENING. THE BULK OF THE HEAVIER RAIN SHOULD BE OVER BY MIDNIGHT...BUT MOIST NORTH NORTHEAST LOW LEVEL FLOW WILL RESULT IN SOME SCATTERED SHOWERS AND AREAS OF DRIZZLE PERSISTING...ESPECIALLY NEAR THE COAST. LOW TEMPS WILL BE IN THE 40S. && .LONG TERM /THURSDAY THROUGH TUESDAY/... */ HIGHLIGHTS... - AN UNSETTLED AND COOL PATTERN THROUGH WEEKS END - POTENTIALLY CLEARING OUT OVER THE WEEKEND IN WAKE OF A COLD FRONT - THE POTENTIAL NEXT WEEK FOR A MORE TYPICAL PATTERN FOR MAY */ DISCUSSION... A COOL UNSETTLED WEATHER PATTERN SETTING UP THROUGH EARLY NEXT WEEK GIVEN THE BLOCKY PATTERN. ENSEMBLE FORECAST APPROACH PREFERRED GIVEN ANOMALOUS SETUP OF 3 TO 4 STANDARD DEVIATIONS BELOW-AVERAGE ATYPICAL FOR MAY. THIS PARENT WITH A DEEP TROUGH W EVOLVING INTO A CLOSED CUT- OFF LOW BY WEEKS END PRIOR TO N-STREAM KICKER OVER THE WEEKEND. LOTS OF ENERGY WITHIN THE OVERALL PATTERN DRAWING AND FORCING MOISTURE N AS COOLER AIR IS ISENTROPICALLY DRAWN S. DAMP AND DREARY GIVEN THE LIKELIHOOD A MAJORITY OF THE FORECAST PERIOD WILL BE SOCKED IN BY CLOUDS AND POSSIBLY FOG/DRIZZLE GIVEN DOMINANT N/NE ONSHORE FLOW. MAYBE A BRIEF BREAK PRIOR TO THE N-STREAM KICKER AND ATTENDANT COLD FRONT CENTERED AROUND SUNDAY. CHANCE TO LIKELY POPS THROUGHOUT. FOR NEXT WEEK A MORE AVERAGE AND DRIER WEATHER PATTERN POSSIBLY SETS UP WITH DOMINANT W/SW FLOW MORE TYPICAL FOR THE MONTH OF MAY. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH WEDNESDAY NIGHT/... TONIGHT...MODERATE CONFIDENCE. MVFR CONDITIONS WILL PROBABLY DOMINATE WITH LOW CLOUDS TRAPPED BENEATH THE SUBSIDENCE INVERSION. HOWEVER...SOME LOCATIONS NORTH OF THE PIKE AND ESPECIALLY NORTHEAST MA MAY IMPROVE TO VFR FOR A TIME AS DRIER AIR TEMPORARILY TRIES TO WORK INTO THIS REGION. MEANWHILE...MAINLY IFR CONDITIONS PROBABLY PERSIST ACROSS THE CAPE AND ISLANDS. WEDNESDAY...MODERATE CONFIDENCE. MVFR CONDITIONS AGAIN EXPECTED TO BE THE RULE FOR MUCH OF THE DAY...BUT SOME MARGINAL VFR CONDITIONS MAY OCCUR. MEANWHILE...IFR CONDITIONS MAY PERSIST ACROSS THE CAPE/ISLANDS GIVEN NORTHEAST FLOW. A FEW SHOWERS POSSIBLE THROUGH MID AFTERNOON...BUT A BAND OF STEADY RAIN WILL LIKELY MOVE INTO THE REGION FROM SOUTHWEST TO NORTHEAST LATE IN THE AFTERNOON/EVENING. LOW RISK OF AN EMBEDDED THUNDERSTORM OR TWO ACROSS SOUTHEAST NEW ENGLAND WEDNESDAY EVENING. WEDNESDAY NIGHT...MODERATE CONFIDENCE. LOW END MVFR TO IFR CONDITIONS EXPECTED. STEADY RAIN FOR MUCH OF THE REGION DURING THE EVENING DIMINISHES TO SCATTERED SHOWERS AND AREAS OF DRIZZLE AFTER MIDNIGHT. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. MVFR CONDITIONS MAY IMPROVE TO VFR FOR A TIME TONIGHT. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. OUTLOOK /THURSDAY - SATURDAY NIGHT/...MODERATE CONFIDENCE. MVFR TO LIFR MIX ESPECIALLY WITH -RA. WORST CONDITIONS POISED E/S ALONG THE COASTS. DOMINANT E/NE FLOW. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH WEDNESDAY NIGHT/...HIGH CONFIDENCE. TONIGHT AND WEDNESDAY...PERSISTENT NORTHEAST FLOW WILL BUILD SEAS TO BETWEEN 3 AND 5 FEET ACROSS OUR SOUTHERN OUTER-WATERS. SO WHILE WIND SPEEDS WILL GENERALLY NOT EXCEED 20 KNOTS THROUGH MIDDAY WEDNESDAY...WILL STILL NEED SMALL CRAFT HEADLINES FOR SOME 5 FOOT SEAS. PATCHY FOG POSSIBLE AT TIMES AS WELL. WEDNESDAY NIGHT...PRESSURE GRADIENT INCREASES AS WAVE OF LOW PRESSURE APPROACHES FROM THE SOUTH AND COMBINES WITH HIGH PRESSURE OVER THE CANADIAN MARITIMES. NORTHEAST WIND GUSTS TO 25 KNOTS MAY DEVELOP ACROSS A GOOD CHUNK OF OUR WATERS ALONG WITH SEAS BUILDING TO BETWEEN 4 AND 7 FEET. ADDITIONAL SCA HEADLINES WILL LIKELY BE NEEDED...BUT SINCE ITS 3RD PERIOD WILL WAIT UNTIL THE NEXT SHIFT GETS A LOOK AT IT. OUTLOOK /THURSDAY - SATURDAY NIGHT/...MODERATE CONFIDENCE. PERSISTENT E/NE FLOW THOUGH REMAINING BELOW 20 KTS WITH AREAS OF LOW PRESSURE DEVELOPING NE ACROSS THE WATERS AT THE BEGINNING OF THE PERIOD AND AGAIN FRIDAY INTO FRIDAY NIGHT. WAVES BUILDING 5 TO 7 FEET REQUIRING SMALL CRAFTS FOR HAZARDOUS SEAS. CONFIDENCE ON THE OUTER WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR ANZ254>256. && $$ SYNOPSIS...FRANK/SIPPRELL NEAR TERM...FRANK SHORT TERM...FRANK LONG TERM...SIPPRELL AVIATION...FRANK/SIPPRELL MARINE...FRANK/SIPPRELL

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