Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 230716 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 316 AM EDT SAT MAY 23 2015 .SYNOPSIS...
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HIGH PRESSURE WILL BUILD TO THE MID ATLANTIC STATES TODAY... BRINGING COOLER AIR TO THE REGION. WARM AND MUGGY CONDITIONS TO BUILD ACROSS THE REGION BENEATH HIGH PRESSURE INTO NEXT WEEK. SHOULD REMAIN MOSTLY DRY WITH THE BETTER CHANCES FOR WET-WEATHER TO REMAIN MAINLY NORTH AND WEST OF OUR AREA PRIOR TO THE FOLLOWING WEEKEND.
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&& .NEAR TERM /THROUGH TODAY/...
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315 AM UPDATE... STILL SEEING PATCHY MID CLOUDS ON IR SATELLITE ACROSS CENTRAL NEW ENGLAND...SOME OF WHICH HAVE SPILLED INTO NORTHERN MA. THIS HAS KEPT TEMPERATURES HIGHER THAN EXPECTED...BUT WITH DRY AIRMASS IN PLACE WE STILL EXPECT TO SEE FROST/FREEZE IN AREAS WHERE HEADLINES ARE POSTED AS SKIES CLEAR BEFORE DAYBREAK. ELSEWHERE WINDS HAVE STAYED UP JUST ENOUGH TO PREVENT A FREE FALL IN TEMPERATURES. HIGH PRESSURE WILL BUILD TO MID ATLANTIC COAST TODAY...RESULTING IN DRY W/NW FLOW ACROSS SOUTHERN NEW ENGLAND. FORECAST SOUNDINGS SHOW POTENTIAL FOR DEEP MIXING TO AROUND 825 MB THIS AFTERNOON... WHICH WILL BRING 20-25 MPH GUSTS /ESPECIALLY THROUGH MIDDAY BEFORE WINDS ALOFT WEAKEN/. MIXING WILL ALSO BRING DRY AIR DOWN TO SURFACE...SO LOWERED DEWPOINTS INTO TEENS IN COLLABORATION WITH NEIGHBORING OFFICES AS OPPOSED TO 20S OFFERED BY GUIDANCE. ONLY NAM MOS SEEMS TO HAVE A HANDLE ON THIS. DESPITE SUNSHINE AND W FLOW...HIGHS WILL ONLY TOP OUT IN UPPER 50S TO MID 60S.
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&& .SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/...
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SW FLOW GETS UNDERWAY TONIGHT AS HIGH PRESSURE BECOMES POSITIONED OFFSHORE. SHOULD SEE SOME MID LEVEL CLOUDINESS TONIGHT IN ASSOCIATION WITH WEAK SHORT WAVE PASSING THROUGH...BUT LOWER LEVELS REMAIN BONE DRY SO NO RAINFALL IS EXPECTED. LOWS SHOULD FALL BACK INTO 40S AND LOWER 50S. WARMUP STARTS SUN WITH INCREASING SW FLOW AND SUBSIDENCE IN WAKE OF DEPARTING SHORT WAVE. MODEL 2M TEMPERATURES SUPPORT HIGHS WELL INTO 70S OR AROUND 80 AWAY FROM S COAST...WHERE TEMPERATURES SHOULD BE HELD IN 60S TO NEAR 70.
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&& .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
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*/ HIGHLIGHTS... - LOOKING GOOD FOR MEMORIAL DAY - WET-WX CHANCES ACROSS N/W-PORTIONS OF THE NE CONUS THRU THE WEEK - WARM AND MUGGY PATTERN EVOLVING - THE RETURN OF AN ACTIVE WET-WEATHER PATTERN BY NEXT WEEKEND */ DISCUSSION... LONG-TERM PATTERN MORE APPARENT WITH RUN-TO-RUN CONSISTENCY OF MODEL FORECAST GUIDANCE. RIDGE ENHANCES OVER THE E-CONUS AHEAD OF AN OPEN- WAVE W-CONUS TROUGH. WITH THE BERMUDA HIGH MAINTAINED THE LOW-TO MID- LEVEL CONVERGENT FLOW UP AGAINST THE N-CANADA VORTEX IS KEPT N/W OF S NEW ENGLAND THRU WHICH MID-LEVEL ENERGY STRETCHES PROVIDING FORCING OF SW-ISENTROPIC ASCENT OF THE WARM-MOIST CONVEYOR BELT. SUBSIDENCE AND DRY-AIR BENEATH ANTICYCLONIC FLOW IS AFFIRMED FOR S NEW ENGLAND. ANTICIPATING A WARM-MUGGY-DRY PATTERN THROUGH THE END OF THE WEEK PRIOR TO THE RIDGE ERODING UP AGAINST THE CUT-OFF RETROGRADING LOW THROUGH THE NW-ATLANTIC. WITH THE RIDGE ERODING IT IS MORE LIKELY THAT MID-LEVEL ENERGY AND CONVERGENT FLOW CAN SLIP SOUTHWARD PUTTING S NEW ENGLAND IN AN ACTIVE WEATHER PATTERN PERHAPS BY NEXT WEEKEND. SO WILL CONTINUE WITH HIGHER POP-CHANCES N/W KEEPING A MAJORITY OF THE FORECAST PERIOD DRY. STEERING FLOW MAINLY W/SW. S-FLOW BENEATH HIGH PRESSURE/SUBSIDENCE WILL LEAN WITH MUGGY UNSEASONABLY-WARM TEMPERATURES AS WE GO INTO THE WEEK. MAY HAVE TO DEAL WITH PERIODS OF MARINE STRATUS/FOG AS S-FLOW ADVECTS HIGHER DEWPOINT AIR N ACROSS THE COOLER WATERS. FOCUS ON THE OVERNIGHT INTO MORNING PERIODS. WILL HINT AT A SHIFT IN THE WEATHER PATTERN BY THE END OF NEXT WEEKEND.
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&& .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH SUN. W/NW WINDS GUST TO 20-25 KT THROUGH MIDDAY...BEFORE WINDS BACK TO W/SW AND DIMINISH THIS AFTERNOON AND TONIGHT. SW WINDS GUST TO 20-25KT SUN...ESPECIALLY NEAR S COAST. VFR THROUGH PERIOD. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. W/NW FLOW. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY NIGHT... MODERATE CONFIDENCE. MAINLY VFR. LOWEST CIGS MAINLY N/W. SW-WINDS BLUSTERY AT TIMES DURING DAYTIME PERIODS. LOW CONFIDENCE WITH IFR- LIFR MARINE STRATUS / FOG ACROSS THE S/SE-COAST OCCURRING DURING THE OVERNIGHT INTO MORNING PERIODS.
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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. HIGH CONFIDENCE THROUGH SUN. SCA REMAINS POSTED FOR W/NW WINDS GUSTING TO 25KT THROUGH MID MORNING...ESPECIALLY WITHIN A FEW MILES OF SHORE BEFORE DIMINISHING AND BECOMING W/SW THIS AFTERNOON. LIGHTER SW FLOW EXPECTED TONIGHT WITH INCREASING SW WINDS SUN WHICH MAY REACH SCA...ESPECIALLY ON S COASTAL BAYS AND SOUNDS. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY NIGHT... MODERATE CONFIDENCE. PERSISTENT SW-FETCH WITH DAYTIME GUSTS AROUND 20-25 KTS ESP ALONG THE SHORES AND INNER-WATERS WILL RESULT IN WAVE HEIGHTS IN EXCESS OF 5-FEET MOSTLY ON THE OUTER WATERS. LOW CONFIDENCE ON THE POTENTIAL FOR MARINE FOG DURING THE OVERNIGHT INTO MORNING PERIODS.
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&& .FIRE WEATHER...
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W/NW WINDS GUST TO 25 MPH AT TIMES...ESPECIALLY THROUGH MIDDAY BEFORE DIMINISHING. MINIMUM RH DROPS TO 10 TO 20 PERCENT THIS AFTERNOON ACROSS MUCH OF SOUTHERN NEW ENGLAND. ALTHOUGH WE ARE FARTHER ALONG IN GREENUP...DUE TO LACK OF SIGNIFICANT RAINFALL OVER PAST SEVERAL DAYS AND INFORMATION FROM STATE FIRE OFFICIALS... WE WILL ISSUE A SPECIAL WEATHER STATEMENT FOR AN ELEVATED FIRE WEATHER RISK TODAY. DRY PATTERN MAY PERSIST FOR NEXT FEW DAYS...ALTHOUGH RH WILL BE SOMEWHAT HIGHER DUE TO SW FLOW.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...FROST ADVISORY UNTIL 7 AM EDT THIS MORNING FOR MAZ004-009>011- 026. FREEZE WARNING UNTIL 7 AM EDT THIS MORNING FOR MAZ002-003-008. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR ANZ230>237-251-255-256. SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ250- 254.
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&& $$ SYNOPSIS...SIPPRELL/JWD NEAR TERM...JWD SHORT TERM...JWD LONG TERM...SIPPRELL AVIATION...SIPPRELL/JWD MARINE...SIPPRELL/JWD FIRE WEATHER...JWD

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