Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 222313 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 713 PM EDT MON SEP 22 2014 .SYNOPSIS... HIGH PRESSURE WILL BRING DRY WEATHER ALONG WITH MILD DAYS AND COOL NIGHTS THROUGH WEDNESDAY. DISTANT COASTAL LOW PRESSURE MAY GRAZE SE NEW ENGLAND WITH THE LOW RISK FOR FEW SHOWERS WEDNESDAY NIGHT INTO THURSDAY. HIGH PRESSURE RETURNS FRIDAY INTO EARLY NEXT WEEK WITH DRY WEATHER AND UNSEASONABLY WARM AFTERNOON/S. ITS POSSIBLE A FEW RECORD HIGH TEMPS ARE CHALLENGED THIS WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 710 PM UPDATE... CLEAR SKIES IN PLACE EARLY THIS EVENING. WINDS WERE GRADUALLY DIMINISHING AS HIGH PRESSURE WAS BUILDING IN FROM THE WEST. THERE APPEARS TO BE ENOUGH GRADIENT TO LIMIT RADIATIONAL COOLING...SO TEMPS WILL LIKELY STAY ABOVE FROST THRESHOLDS IN MOST LOCATIONS. THE EXCEPTION IS PORTIONS OF NORTHWEST MA/SOUTHWEST NH...WHERE GUIDANCE SHOWS DECOUPLING WINDS AND LOWS BOTTOMING OUT IN THE MIDDLE 30S BY DAYBREAK. WILL GO AHEAD AND HOIST A FROST ADVISORY FOR THAT REGION. ACROSS THE REST OF THE REGION...STILL A CHILLY NIGHT WITH MINS IN UPPER 30S AND 40S. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... TUESDAY... HIGH PRES CRESTS ACROSS THE REGION WHICH WILL BRING MOSUNNY SKIES AND LIGHT WINDS. SUBSIDENCE INVERSION WILL LIMIT MIXING HEIGHT BELOW 850 MB. 925 MB TEMPS 10-11C WHICH SUPPORTS TEMPS 65-70 DEGREES...COOLER HIGHER TERRAIN WHICH IS LINE WITH 2M TEMPS. SOME OF THE HIRES GUIDANCE IS HINTING A SEABREEZE DEVELOPING ALONG THE COAST IN THE AFTERNOON. TUESDAY NIGHT... HIGH PRES BUILDS TO THE NORTH WITH A CONTINUATION OF CLEAR SKIES AND A LIGHT NE WIND DEVELOPING OVERNIGHT. WE USED A BLEND OF THE GUIDANCE WHICH YIELDS MINS MOSTLY IN THE 40S. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... HIGHLIGHTS... * COOL NIGHTS/MILD DAYS WED AND THU * LOW RISK OF A FEW SHOWERS NEAR THE SOUTH COAST WED NIGHT INTO THU * UNSEASONABLY WARM AFTERNOON/S THIS WEEKEND PERHAPS INTO MONDAY * DRY WITH NO APPRECIABLE RAINFALL IN SITE DETAILS... WEDNESDAY... LARGE HIGH PRESSURE CENTERED OVER NORTHERN NEW ENGLAND WILL RESULT IN DRY/PLEASANT WEATHER FOR LATE SEPTEMBER. GIVEN THE POSITIONING OF THE HIGH PRESSURE SYSTEM...EXPECT EASTERLY WINDS AT THE SURFACE SO COOLEST TEMPS WILL BE FOUND NEAR THE EASTERN MA COAST. HIGHS SHOULD RANGE FROM MAINLY THE 60S...TO PERHAPS NEAR 70 IN THE LOWER CT RIVER VALLEY. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT... WE WILL HAVE TO KEEP AN EYE ON A LOW PRESSURE SYSTEM THAT WILL BE EMERGING OFF THE MID ATLANTIC COAST. HOWEVER...WEAK UPPER LEVEL FLOW AND A SURFACE HIGH NEARBY ARE NOT FAVORABLE FOR ALLOWING THE LOW PRESSURE SYSTEM TO TRACK UP THE COAST. IN ADDITION...WEAK BAROCLINICITY WILL ALSO LIMIT NORTHWEST AXIS OF QPF SHIELD. NONETHELESS...THE GFS AND ITS ENSEMBLES INDICATE AT LEAST A LOW RISK FOR A FEW BRIEF SHOWERS ACROSS OUR SOUTHERN ZONES. WHETHER OR NOT THIS COMES TO FRUITION REMAINS TO BE SEEN...BUT CERTAINLY DO NOT EXPECT ANY APPRECIABLE RAINFALL. AS FOR HIGH TEMPS ON THURSDAY...ONSHORE FLOW WILL RESULT IN HIGHS IN THE 60S TO NEAR 70. AGAIN...MILDEST READINGS WILL BE FOUND ACROSS THE DISTANT INTERIOR. LOW TEMPS WED NIGHT AND THU NIGHT SHIELD BE IN THE 40S...TO THE LOWER 50S. FRIDAY THROUGH MONDAY... ANOMALOUS UPPER LEVEL RIDGING TAKES HOLD OF THE NORTHEAST U.S. FROM FRI INTO EARLY NEXT WEEK. THIS WILL RESULT IN DRY WEATHER WITH UNSEASONABLY WARM AFTERNOON/S. NEAR RECORD HIGH TEMPS POSSIBLE THIS WEEKEND. ANOTHER FACTOR THAT MAY HELP IN THIS PROCESS IS THE VERY DRY GROUND...WHICH MAY ALLOW HIGH TEMPS TO GET A DEGREE OR SO HIGHER THAN THEY NORMALLY WOULD IN THIS SET UP. GUIDANCE NUMBERS HAVE LIKELY TRENDED TOO MUCH TOWARDS CLIMATOLOGY. HIGH TEMPS FRI...SHOULD BE WELL UP INTO THE 70S. SAT/SUN LOOKS LIKE THE WARMEST DAYS...WHERE HIGHS WILL PROBABLY REACH 80+ ACROSS THE LOWER ELEVATIONS AND AREAS AWAY FROM THE COAST. LOW CONFIDENCE ON HIGH TEMPS FOR MONDAY...WILL DEPEND WHETHER OR NOT A BACKDOOR COLD FRONT COOLS US OFF A BIT LIKE THE 12Z ECMWF DEPICTS. GFS IS STILL QUITE WARM...BUT OBVIOUSLY WERE A WEEK OUT SO THAT IS UNCERTAIN. AS LAST SHIFT POINTED OUT...DRY AIRMASS WILL KEEP HUMIDITY IN CHECK SO AFTERNOON/S WILL BE NICE FOR OUTDOOR ACTIVITIES. RECORD HIGH TEMPS THIS WEEKEND INTO NEXT MONDAY: SAT 9/27...SUN 9/28... MON 9/29... BOS...86...1998 BOS...90...1881 BOS...88...1952 BDL...88...1998 BDL...83...1959 BDL...86...1945 PVD...86...1998 PVD...84...1943 PVD...87...1945 ORH...85...1933 ORH...84...1916 ORH...84...1952 && .AVIATION /22Z MONDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY NIGHT/... HIGH CONFIDENCE. VFR AS GUSTY WINDS CONTINUE TO DIMINISH THIS EVENING. LIGHT WINDS TUE AND TUE NIGHT WITH LOW PROB OF A SEABREEZE TUE AFTERNOON. KBOS TERMINAL...HIGH CONFIDENCE. LOW PROB OF A SEABREEZE TUE AFTERNOON. KBDL TERMINAL...HIGH CONFIDENCE. OUTLOOK...WEDNESDAY THROUGH SATURDAY... HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE PERIOD...OTHER THAN BRIEF LATE NIGHT/EARLY MORNING PATCHY GROUND FOG IN THE TYPICALLY PRONE LOCALES. THERE IS A LOW RISK FOR A BRIEF PERIOD OF MVFR CONDITIONS NEAR THE SOUTH COAST/CAPE AND ISLANDS WED NIGHT INTO THU NIGHT. THIS WILL DEPEND UPON WHETHER A FEW SHOWERS CAN MAKE IT THAT FAR NORTH WITH AN OFFSHORE LOW PRESSURE SYSTEM. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY NIGHT/...HIGH CONFIDENCE. TONIGHT...GUSTY WINDS WILL GRADUALLY DIMINISH TONIGHT WITH GUSTS DROPPING BELOW SCA THRESHOLDS THIS EVENING. HOWEVER...SOUTHERLY SWELL WILL KEEP SEAS ABOVE 5 FT OVER THE OPEN WATERS THROUGH THE NIGHT SO SMALL CRAFT ADVISORIES WILL CONTINUE HERE. TUE AND TUE NIGHT...LIGHT WINDS BELOW 15 KT WITH SEAS SUBSIDING BELOW 5 FT DURING TUE OVER THE OPEN WATERS. LIGHT WINDS AND SEAS TUE NIGHT. OUTLOOK...WEDNESDAY THROUGH SATURDAY... MODERATE TO HIGH CONFIDENCE... THE MAIN CONCERN WILL BE A LOW PRESSURE SYSTEM THAT WILL TRACK NEAR OR SOUTHEAST OF THE BENCHMARK WED NIGHT INTO THU. IT WILL LIKELY RESULT IN ENOUGH SWELL FOR SCA SEAS TO DEVELOP ACROSS THE SOUTHERN OPEN WATERS WED NIGHT. SCA SWELL MAY PERSIST ACROSS THE OUTER WATERS RIGHT INTO FRI AFTERNOON BEFORE DIMINISHING. WINDS SHOULD GENERALLY REMAIN BELOW SCA THRESHOLDS THROUGH THE PERIOD. HOWEVER...A PERIOD OF NORTHEAST WIND GUSTS OF 20 TO 25 KNOTS ARE POSSIBLE ACROSS THE SOUTHERN WATERS WED NIGHT/THU IF COASTAL LOW PRESSURE TRACKS CLOSE ENOUGH TO OUR REGION. VISIBILITIES SHOULD BE GOOD THROUGH MOST IF NOT ALL OF THE PERIOD. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...FROST ADVISORY FROM 2 AM TO 7 AM EDT TUESDAY FOR MAZ003. NH...FROST ADVISORY FROM 2 AM TO 7 AM EDT TUESDAY FOR NHZ011. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ231>234-251. SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ235-237. SMALL CRAFT ADVISORY UNTIL 11 AM EDT TUESDAY FOR ANZ250- 254>256. && $$ SYNOPSIS...KJC/FRANK NEAR TERM...KJC/FRANK SHORT TERM...KJC LONG TERM...FRANK AVIATION...KJC/FRANK MARINE...KJC/FRANK

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