Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 151105 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 705 AM EDT MON SEP 15 2014 .SYNOPSIS... HIGH PRESSURE FROM NORTHERN NEW ENGLAND TO PENNSYLVANIA WILL SLIDE SOUTHEASTWARD ACROSS THE REGION TODAY AND OFF THE COAST TONIGHT. A COLD FRONT WILL MOVE ACROSS THE AREA LATE MONDAY NIGHT AND TUESDAY MORNING BRINGING A ROUND OF SHOWERS...THEN CLEARING. MAINLY DRY BUT COOLER THAN NORMAL WEATHER FOLLOWS NEXT WEDNESDAY THROUGH SATURDAY. TEMPERATURES THEN LIKELY MODERATE TO NEAR NORMAL BY NEXT SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 700 AM UPDATE... OVERALL TRENDS IN THE FORECAST REMAIN ON TRACK THIS MORNING. HAVE DROPPED THE FROST ADV AS MANY SITES ARE AT OR ABOVE 40F AND WITH SUNRISE...WILL ONLY GET WARMER. THUS FAR A FEW SITES IN NH DID DROP AT OR BELOW 36F LAST NIGHT PER COOP SITES. OTHERWISE MID LEVEL CLOUD DECK WILL MOVE ACROSS THE REGION THIS MORNING. FINALLY ANY PATCHY GROUND FOG WILL DISSIPATE WITHIN THE HOUR AS DIURNAL HEATING BEGINS. PREVIOUS FORECAST... SKY COVER IS A BIT OF A TRICKY FORECAST THIS MORNING. THE RAP MODEL RH AT 925 MB HAS THE BEST HANDLE ON EXTENSIVE LOW CLOUDINESS THAT HAS FORMED IN THREE MAIN AREAS...CENTRAL AND EASTERN NY STATE...CAPE COD AND PLYMOUTH COUNTY...AND EAST COAST OF NH. SCATTERED LOW CLOUDS HAD FORMED OVERNIGHT IN OTHER AREAS...SUCH AS WORCESTER COUNTY AS WELL. THE CLOUDS SEEM TO BE THE RESULT OF A COLD POOL IN THE 850-700 MB LAYER MOVING ACROSS EASTERN NY AND SOUTHERN NEW ENGLAND. THE TEMPERATURES IN THAT LAYER COOL UNTIL ABOUT 15-18Z AND THEN THEY BEGIN TO WARM ACROSS SOUTHERN NEW ENGLAND. CLOUDS HAVE BASES MAINLY 4000-5000 FT IN EASTERN NY AND THUS SHOULD MAKE IT OVER THE BERKSHIRES. HAVE INCREASED SKY COVER TO 60-70 PCT IN MUCH OF SNE...ESPECIALLY N OF THE MA PIKE FOR THE EARLY TO MID MORNING HOURS. IN ADDITION...AM EXPECTING CLOUD COVER TO BECOME WIDESPREAD OVER THE WATER ALONG THE E COAST OF MA AS THE COLDER AIR MOVES OVER THE RELATIVELY WARMER WATERS...BREAKING UP THIS AFTERNOON. AGAIN...A TRICKY FORECAST. BY THIS AFTERNOON MOST AREAS SHOULD BECOME PARTLY TO MOSTLY SUNNY AND THUS THE HIGH TEMPERATURE FORECAST SHOULD STILL BE ABOUT AS FORECAST PREVIOUSLY...MAINLY MID AND UPPER 60S EXCEPT NEAR 70 IN INTERIOR SE MA. LIGHT WINDS. SHOULD SEE SOME LIGHT SEA BREEZES DEVELOP ALONG E COASTAL MA AND SOUTHERN RI IN THE AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... TONIGHT...DRY WEATHER IS EXPECTED UNTIL WELL AFTER MIDNIGHT AS HIGH PRESSURE MOVES OFFSHORE. A COLD FRONT TRAILING FROM LOW PRESSURE IN NORTHERN QUEBEC WILL APPROACH WESTERN NEW ENGLAND LATE TONIGHT. SHOWERS WILL BECOME LIKELY TOWARD DAYBREAK IN WESTERN MA AND SOUTHWEST NH AND THERE IS A CHANCE OF SHOWERS ELSEWHERE. THERE IS ALSO POTENTIAL FOR SOME AREAS OF FOG. LIGHT SOUTHWEST WINDS AND INCREASING CLOUD COVER WILL PREVENT TEMPERATURES FROM BOTTOMING OUT LIKE THEY DID THIS MORNING. EXPECTING LOWS IN THE MID 40S TO MID 50S. TUESDAY... A WEAK LOW PRESSURE AREA MAY DEVELOP SOUTH OF NEW ENGLAND ALONG THE COLD FRONT THAT WILL BE PASSING THROUGH. THE FRONT AND ASSOCIATED LOW PRESSURE WILL EXIT THE COAST IN THE MID TO LATE AFTERNOON. SCATTERED SHOWERS IN THE MORNING WILL END AND SKIES SHOULD BECOME PARTLY SUNNY AS THE DAY PROGRESSES. RAINFALL AMOUNTS SHOULD BE LESS THAN ONE QUARTER OF AN INCH...ALTHOUGH THE 00Z ECMWF RUN HAS AS MUCH AS 0.4 INCHES IN A FEW SPOTS. HIGHS AGAIN MAINLY 65 TO 70. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * MAINLY DRY WEATHER WITH BELOW NORMAL TEMPS WED THROUGH SAT * FROST POTENTIAL FOR PORTIONS OF INTERIOR EARLY FRI/SAT MORNING/S * SHORT LIVED MILDER WEATHER LOOKS TO RETURN BY SUNDAY. OVERVIEW... 00Z MODEL GUIDANCE IS IN VERY GOOD AGREEMENT SYNOPTICALLY WITH JUST MINOR DIFFERENCES AT THE SURFACE. OVERALL...MEAN TROUGH OVER THE NORTHEAST PORTION OF THE NATION WILL PERSIST THROUGH MOST OF THE UPCOMING WEEK BEFORE LIFTING INTO THE MARITIMES BY NEXT WEEKEND. GUIDANCE SHOWS A BRIEF WARM-UP SUN/MON HOWEVER LOOKS TO BE SHORT- LIVED AND THE TROUGH WILL ONCE AGAIN REESTABLISH ITSELF BY NEXT WEEK. SINCE GUIDANCE IS IN GOOD AGREEMENT...USED A BLEND OF DETERMINISTIC AND ENSEMBLES FOR THIS FORECAST. DETAILS... TUESDAY NIGHT INTO WEDNESDAY NIGHT... DRIER AND COOLER AIR WILL MOVE IN BEHIND THE FRONT TUE NIGHT AS HIGH PRESSURE BUILDS ACROSS NEW ENGLAND. SKIES SHOULD GENERALLY BECOME MOSTLY CLEAR ALLOWING FOR TEMPS TO RADIATE OUT OVERNIGHT. ANTICIPATE TEMPS TO BE BELOW AVERAGE WITH LOWS IN THE LOW TO UPPER 40S AND HIGHS BARELY REACHING 70 IN SPOTS. THURSDAY NIGHT INTO SATURDAY... A DRY COLD FRONT WILL MOVE ACROSS THE REGION ON THURSDAY REINFORCING THE DRY...COOL AIR ALREADY IN PLACE. THERE IS A LOW PROBABILITY OF A SPOT SHOWER WHEN THE FRONT MOVES THROUGH BUT DUE TO LACK OF MOISTURE KEPT OUT OF THE FORECAST FOR NOW. CANADIAN HIGH PRESSURE BUILDS INTO THE REGION THURSDAY NIGHT LASTING INTO SATURDAY. THIS HIGH WILL KEEP TEMPS BELOW AVG FOR THIS TIME OF YEAR. LOW TEMPS WILL BE IN THE 30S ACROSS THE NORMALLY COOLER OUTLYING AREAS OF SOUTHWEST NH/WESTERN MA...WHERE FROST HEADLINES WILL LIKELY BE REQUIRED EARLY FRI/SAT MORNING/S. THE REST OF THE REGION SHOULD SEE LOWS MAINLY IN THE 40S. SUNDAY INTO MONDAY... HIGH PRESSURE MOVING OFF THE COAST SATURDAY NIGHT WILL ALLOW FOR RETURN FLOW AND WARMER MID LEVEL AIR TO MOVE INTO THE REGION. HIGHS SHOULD TOP OUT WELL INTO THE MID 70S ON SUNDAY AND MONDAY. MOST OF THE FORCING FOR ORGANIZED PRECIP SHOULD REMAIN TO OUR NORTH AND WEST OVER THIS TIME...BUT CAN/T RULE OUT A FEW SPOT SHOWERS IN THE WARM ADVECTION PATTERN. AT THIS TIME...WILL JUST INCLUDE SLIGHT CHANCE POPS. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. TODAY...MODERATE CONFIDENCE. MAINLY VFR. MID-LEVEL DECK WILL MOVE ACROSS THE REGION THIS MORNING. SHOULD BE SKC BY THIS AFTERNOON. SEA BREEZES ALONG BOTH COASTLINES. TONIGHT...MODERATE CONFIDENCE. VFR EXCEPT AREAS OF MVFR MAINLY CAPE COD AND ISLANDS. MVFR/IFR CONDITIONS DEVELOPING IN SHOWERS AFTER ABOUT 08Z IN NW MA SW NH. LOW RISK OF PATCHY MVFR FOG INLAND. TUESDAY...MODERATE CONFIDENCE. SHOWERS WITH MVFR TO PERHAPS EVEN LOCALLY IFR CONDITIONS EXPECTED IN THE MORNING. CONDITIONS IMPROVE TO VFR FROM WEST TO EAST DURING THE AFTERNOON. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SEA BREEZE SHOULD MOVE IN BETWEEN 15-17Z. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY. TUESDAY NIGHT THROUGH FRIDAY...HIGH CONFIDENCE. VFR CONDITIONS EXPECTED OTHER THAN A TOUCH OF BRIEF EARLY MORNING PATCHY GROUND FOG IN THE TYPICALLY PRONE LOCATIONS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. TODAY THROUGH TUESDAY...HIGH CONFIDENCE. LIGHT WINDS AND GOOD VISIBILITY THROUGH MOST OF MONDAY NIGHT AS HIGH PRESSURE MOVES ACROSS THE WATERS. THERE IS A CHANCE OF SHOWERS VERY LATE MONDAY NIGHT AND TUESDAY AS A COLD FRONT MOVES ACROSS THE WATERS AND A WAVE OF LOW PRESSURE PASSES THROUGH. SEAS COULD BUILD TO NEAR 5 FT LATE TUE AFTERNOON IN THE SOUTHEASTERN OUTER WATERS OTHERWISE WINDS AND SEAS WILL BE WELL BELOW SCA THRESHOLDS. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY... TUESDAY NIGHT AND WEDNESDAY...MODERATE TO HIGH CONFIDENCE. A DEPARTING COLD FRONT WILL SWITCH THE WINDS TO THE NW AND GUST UP TO 20 KNOTS. SEAS AS WELL WILL INCREASE IN RESPONSE AND WILL REACH AT OR ABOVE 5FT ON THE OUTER WATERS. SCA MAY BE NEEDED. THURSDAY AND FRIDAY...MODERATE TO HIGH CONFIDENCE. A REINFORCING COLD FRONT WILL MOVE THROUGH THE REGION ON THU. MARGINAL SCA SEAS AND NORTHERLY WIND GUSTS TO 25 KNOTS EXPECTED TO DEVELOP LATE THU INTO FRI ACROSS SOME OF THE OUTER-WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...DUNTEN/GAF NEAR TERM...DUNTEN/GAF SHORT TERM...GAF LONG TERM...DUNTEN AVIATION...DUNTEN/GAF MARINE...DUNTEN/GAF

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