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Area Forecast Discussion
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000
FXUS61 KBOX 302309
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
709 PM EDT TUE SEP 30 2014

.SYNOPSIS...
COOL DAMP CONDITIONS REMAIN IN PLACE INTO THURSDAY...WITH MORE
WIDESPREAD RAINFALL EXPECTED TOMORROW. DRY WEATHER RETURNS LATER
THURSDAY INTO FRIDAY AS HIGH PRESSURE BUILDS BACK ACROSS THE
REGION. A COLD FRONT WITH ASSOCIATED LOW PRESSURE WILL LIKELY
BRING A PERIOD OF RAIN SATURDAY FOLLOWED BY COOLER AND DRIER
CONDITIONS FOR SUNDAY INTO MONDAY.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
7 PM UPDATE...
AREA OF LIGHT RAIN IS DIMINISHING ACROSS SNE AS WV LOOP SHOWS
DEEPER MOISTURE MOVING OFF TO THE EAST. HOWEVER...GIVEN ALL THE
N-NE FLOW OFF THE COOL GULF OF MAINE...WILL LIKELY SEE AREAS OF
DRIZZLE AND PATCHY FOG DEVELOP THROUGH THIS EVENING. 

MID LEVEL LOW SPINNING NEAR LAKE ERIE WITH ASSOCD COLD POOL
HELPING TO TRIGGER CONVECTION ACROSS CENTRAL PA AND W NY.
INSTABILITY IS EXPECTED TO DIMINISH TONIGHT SO THUNDER NOT
ANTICIPATED FOR SNE...BUT WE EXPECT RAIN TO EXPAND ACROSS THE
REGION OVERNIGHT AS THE MID LEVEL LOW APPROACHES SNE FROM THE
WEST AND MID LEVEL OMEGA INCREASES ALONG WITH DEEPENING MOISTURE.

PREVIOUS DISCUSSION...
THROUGH THE EARLY MORNING HOURS HOWEVER...EXPECT INVERTED TROF
BETWEEN THE OFFSHORE LOW PRES AND THE E MOVING UPPER CUTOFF TO
BEGIN TO ENHANCE. NOTE INCREASE IN BAROCLINICITY AND DEFORMATION
ACROSS THE AREA THROUGH THE MORNING...WHICH COMBINED WITH
DEEPENING MOISTURE FROM THE SFC TO H4 OR SO...SUSPECT INCREASE IN
MORE WIDESPREAD RAINFALL ACROSS SRN NEW ENGLAND DURING THE EARLY
MORNING HOURS...SUCH THAT IT/S LIKELY RAINING AT OVER MUCH OF THE
BOX CWA BY 12Z. 

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
TOMORROW...
AS MENTIONED ABOVE...AS UPPER LVL CUTOFF SHIFTS ALMOST DIRECTLY
OVERHEAD AND LOW PRES CONTINUES WELL TO THE SE OF THE
BENCHMARK...A MODERATE INVERTED TROF IS LIKELY TO CONTINUE TO
DEVELOP THROUGH THE MORNING AND INTO THE AFTERNOON. THIS PROVIDES
BETTER F-GEN AND EVEN A DEFORMATION AXIS FOR DEEPER LIFT ACROSS
THE AREA. THIS IS ALSO COMBINED WITH MODEST ELY LLJ WITH WIND
SPEEDS AT H85 AROUND 25-30 KT /2+ STD DEVIATIONS ABOVE NORMAL/
AND PWATS TO AROUND 1.5 INCHES WHICH IS 1-2 STD DEVIATIONS ABOVE
NORMAL FOR EARLY OCTOBER. THEREFORE...EXPECT MORE WIDESPREAD
RAINFALL ACROSS MOST OF SRN NEW ENGLAND THROUGH THE DAY...ITS NOT
UNTIL THE SFC OCEAN SYSTEM PULLS E LATE IN THE DAY THAT THE
MOISTURE BEGINS TO DECREASE. MANY AREAS MAY RECEIVE SOME OF THE
STEADY SOAKING RAINFALL THEY HAVE NEEDED FOR SOME TIME NOW WITH
THE POSSIBILITY OF RAINFALL AMOUNTS RANGING 0.25-0.75 INCHES.
POCKETS OF HEAVIER RAIN ARE ALSO POSSIBLE GIVEN THE BANDING
POTENTIAL WHICH MAY BE ENHANCED THANKS TO K-VALUES IN THE LOW
30S...BUT IT/S DIFFICULT TO SAY EXACTLY WHERE THIS WILL SET UP. SO
WILL AT LEAST HIGHLIGHT THE POTENTIAL FOR SOME LOCALIZED AREAS OF
1.0+ INCHES. FOR NOW...THE BEST CHANCE LOOKS LIKE SE MA...WHERE
THE INVERTED TROF HOLDS IN THE LONGEST...BUT IT/S NOT OUT OF THE
QUESTION IT IS OBSERVED INLAND...ESPECIALLY WHERE AN E COMPONENT
TO THE FLOW ENHANCES UPSLOPE.

OTHER THAN THE RAINFALL...COOL TEMPS ARE EXPECTED AS MANY
LOCATIONS REMAIN IN THE UPPER 50S TO AROUND 60 DEGREES.

TOMORROW NIGHT...
RAINFALL WILL SLOWLY COME TO AN END FROM W TO E THROUGH THE
EVENING...POSSIBLY LINGERING ACROSS RI AND SE MA INTO THE EARLY
MORNING HOURS. HOWEVER...WITH E COMPONENT TO THE FLOW...AND LOW
LVL MOISTURE REMAINING IN PLACE...EXPECT ANOTHER CHANCE FOR FOG
AND DRIZZLE AT TIMES THROUGH THE OVERNIGHT HOURS. MIN TEMPS REMAIN
LIKELY IN THE 50S.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...

* SUNSHINE AND LIGHT WINDS FRIDAY
* RAIN LIKELY SATURDAY
* COOLER AND MAINLY DRY WEATHER SUNDAY INTO MONDAY
* MORE SHOWERS POSSIBLE TUESDAY

OVERVIEW... 
MEDIUM RANGE DETERMINISTIC AND ENSEMBLE GUIDANCE IN GENERAL 
AGREEMENT ON THE LARGE SCALE PATTERN DURING THE EXTENDED PERIOD. MID 
LEVEL LOW EXITS THE REGION TOWARD THE END OF THE WEEK...THEN MAIN 
FEATURE WILL BE AN ANOMALOUS MID LEVEL TROF/LOW DIGGING INTO THE 
UPPER MIDWEST AND WESTERN GT LAKES BY SAT. A PIECE OF ENERGY 
ROTATING AROUND THE MID LEVEL LOW WILL BRING A FRONTAL SYSTEM INTO 
NEW ENG LATE SAT/SAT NIGHT WHICH WILL BE ACCOMPANIED BY A PERIOD OF 
RAIN WHICH MAY BE LOCALLY HEAVY...BUT EXACT TIMING IS UNCERTAIN. 
AFTER SHORTWAVE EXITS...BROAD TROF WILL REMAIN ACROSS SOUTHERN 
CANADA AND GT LAKES SUNDAY INTO EARLY NEXT WEEK WITH NEXT SHORTWAVE 
AND FRONT APPROACHING NEXT TUESDAY. THERE ARE ALSO TIMING 
DIFFERENCES WITH THIS FRONT AS THE GFS IS MORE PROGRESSIVE THAN THE 
ECMWF WHICH WILL AFFECT TIMING OF POTENTIAL SHOWERS EARLY NEXT WEEK. 

DAILIES... 

THURSDAY...
MID LEVEL LOW WILL GRADUALLY PULL AWAY FROM SE NEW ENG AS HIGH PRES 
BUILDS INTO THE REGION.  CROSS SECTIONS SUGGEST MOCLDY SKIES DURING 
THE MORNING AND CANT RULE OUT A FEW SHOWERS NEAR THE COAST IN 
PERSISTENT CYCLONIC FLOW...THEN BECOMING PTSUNNY FROM WEST TO EAST 
IN THE AFTERNOON AS DRIER AIR MOVES IN. WITH NE FLOW... TEMPS WILL 
HOLD IN THE 60S.

FRIDAY... 
SNE WILL BE IN BETWEEN SYSTEMS WITH HIGH PRES OVERHEAD LEADING TO 
MOSUNNY SKIES AND LIGHT WINDS.  WILL HAVE TO WATCH CLOUDS BACKING IN 
FROM THE OCEAN ASSOCIATED WITH OFFSHORE STORM WHICH MAY BRING MORE 
CLOUDS TO THE OUTER CAPE.  GFS AND NAM ARE SUGGESTING THIS INCREASED 
CLOUD COVER WHILE ECMWF KEEPS CLOUDS TO THE EAST.  WITH CONTINUED 
ONSHORE FLOW TEMPS EXPECTED TO BE IN THE 60S...COOLEST E MA COAST. 
 
SATURDAY INTO SATURDAY NIGHT...
MODELS ARE IN GOOD AGREEMENT ON TIMING OF COLD FRONT INTO SNE LATE 
SAT INTO SAT NIGHT. DECENT LOW LEVEL JET AND ANOMALOUS PWAT PLUME 
AHEAD OF THE FRONT WILL BRING A PERIOD OF RAIN TO SNE WHICH MAY BE 
LOCALLY HEAVY...BUT THIS SYSTEM IS FAIRLY PROGRESSIVE. TIMING IS 
STILL UNCERTAIN BUT IT APPEARS BULK OF RAIN WILL FALL DURING 
SAT...WHICH MAY LINGER INTO SAT EVENING ACROSS E NEW ENG.   

SUNDAY...
FRONT IS OFFSHORE SUNDAY WITH DRY WESTERLY FLOW WHICH WILL LEAD TO 
SUNSHINE AND BLUSTERY CONDITIONS. 850 MB TEMPS BELOW NORMAL AND WILL 
LEAD TO BELOW NORMAL TEMPS SUNDAY.

MONDAY AND TUESDAY... 
NEXT FRONT APPROACHES FROM THE WEST BUT THERE ARE DIFFERENCES IN 
TIMING AND AMPLITUDE OF THE SHORTWAVE AND HOW PROGRESSIVE THE FRONT 
WILL BE. EVEN FASTER GFS IS MAINLY DRY FOR MON SO WE ARE GOING WITH 
A DRY FORECAST FOR NOW.  THE MAIN UNCERTAINTY IS WITH TUE AS 
PROGRESSIVE GFS MOVES THE SHOWERS OFFSHORE WHILE MORE AMPLIFIED 
ECMWF IS WET.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT. 
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

SHORT TERM...HIGH CONFIDENCE ON TRENDS BUT LOWER CONFIDENCE IN
TIMING.

THROUGH TONIGHT...
MAINLY IFR EAST OF AN IJD-ORH-MHT LINE...WITH MVFR WEST. THIS IS
MAINLY DUE TO CIGS THROUGH EVENING...BUT VSBYS MAY BEGIN TO DIP
AS WELL TONIGHT IN A MIX OF DRIZZLE/FOG/LIGHT RAIN. POSSIBILITY
OF PERIODIC IFR VSBYS. CIGS REMAIN LOW...BUT VSBYS LIFT DURING
THE MORNING HOURS AS RAIN BECOMES MORE WIDESPREAD AND ALLOWS VSBYS
TO LIFT TO MAINLY MVFR/VFR. WINDS PICK UP NEAR SHORE IN THE
EAST...WITH A FEW GUSTS APPROACHING 20 KT AT COASTAL TERMINALS.

TOMORROW AND TOMORROW NIGHT....
MUCH OF THE SAME...MAINLY IFR/MVFR CIGS WITH SOME MVFR CONDITIONS
IN RAIN. EXPECT A VERY SLOW IMPROVEMENT FROM W TO E LATE IN THE
DAY AND OVERNIGHT...BUT THIS WILL BE MAINLY TOWARD RAIN
ENDING...WITH CATEGORIES ONLY REALLY IMPROVING DURING THE DAYLIGHT
HOURS ON THU.

KBOS...HIGH CONFIDENCE ON TRENDS...LOWER CONFIDENCE ON TIMING.
ALSO LOW CONFIDENCE OF A BRIEF PERIOD OF LIFR CONDITIONS POSSIBLE
DURING THE OVERNIGHT HOURS BEFORE IMPROVEMENT IN THE MORNING.

KBDL...HIGH CONFIDENCE ON TRENDS...LOWER CONFIDENCE ON TIMING.

OUTLOOK...THURSDAY THROUGH SUNDAY...

THU...MODERATE CONFIDENCE. AREAS OF IFR IN THE MORNING SHOULD 
IMPROVE TO VFR IN THE AFTERNOON AS CIGS LIFT AND CLOUDS BREAK UP. 

FRI...HIGH CONFIDENCE. VFR.

SAT...MODERATE CONFIDENCE.  CONDITIONS LOWERING TO MVFR/IFR AS 
SHOWERS MOVE INTO THE REGION. LOWER CONFIDENCE ON TIMING. GUSTY 
SOUTHERLY WINDS POSSIBLE AHEAD OF A COLD FRONT SHIFTING TO WEST SAT 
NIGHT.

SUN...MODERATE CONFIDENCE. VFR.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT. 
MODERATE...30 TO 60 PERCENT. 
HIGH...GREATER THAN 60 PERCENT.

SHORT TERM...HIGH CONFIDENCE THROUGH TOMORROW NIGHT.

N-NE FLOW WILL GRADUALLY INCREASE THROUGH THE EARLY MORNING HOURS
INTO TOMORROW...WITH WIND GUSTS AROUND 25 KT AT TIMES POSSIBLE
PARTICULARLY BY TOMORROW AFTERNOON AND OVERNIGHT. SMALL CRAFT
ADVISORIES HAVE BEEN ISSUED FOR THE OCEAN WATERS AS WELL AS RI/BI
SOUND FOR THESE WINDS...AND MAY NEED TO BE ADDED FOR THE WATERS
SURROUNDING CAPE COD FOR LATE IN THE DAY TOMORROW.

OTHERWISE...SMALL CRAFT ADVISORY CONDITIONS ARE LIKELY DUE TO
INCREASING SWELL ALONE...WHICH HAS THE POTENTIAL TO REACH 7-8FT
BY TOMORROW AFTERNOON ON THE OCEAN WATERS. IT/S LIKELY THAT THESE
SMALL CRAFT ADVISORIES WILL NEED TO LINGER INTO THURSDAY.

OUTLOOK...THURSDAY THROUGH SUNDAY...MODERATE CONFIDENCE.

THU INTO FRI...EXPECT NE WIND GUSTS TO 25-30 KT THU MORNING OVER SE 
WATERS WHICH WILL GRADUALLY DIMINISH THU AFTERNOON AND NIGHT. 
CONTINUED NE WINDS FRI BUT SPEEDS LESS THAN SCA.  HAZARDOUS SEA 
CONDITIONS EXPECTED THU INTO FRI OVER OUTER WATERS. 

SAT...SOUTHERLY WINDS DEVELOPING AHEAD OF A COLD FRONT WITH GUSTS 
INCREASING TO 25-30 KT. WINDS SHIFTING TO WEST DURING SAT NIGHT. 
HAZARDOUS SEA CONDITIONS CONTINUE OVER OUTER WATERS.  VSBYS MAY BE 
REDUCED IN SHOWERS AND FOG.

SUN...WEST WINDS MAY GUST TO 25-30 KT IN POST FRONTAL AIRMASS. 
HAZARDOUS SEAS CONTINUE OVER OUTER WATERS.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM WEDNESDAY TO 8 AM EDT THURSDAY 
     FOR ANZ235-237.
     SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR ANZ250-251.
     SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 8 AM EDT 
     THURSDAY FOR ANZ254>256.

&&

$$
SYNOPSIS...KJC/DOODY
NEAR TERM...KJC/DOODY
SHORT TERM...DOODY
LONG TERM...KJC
AVIATION...KJC/DOODY
MARINE...KJC/DOODY



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