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Area Forecast Discussion
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000
FXUS61 KBOX 301742
AFDBOX

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

.SYNOPSIS...
COOL TEMPERATURES EXPECTED THROUGH MOST OF THIS WEEK AS
PERSISTENT NORTHEAST WINDS REMAIN IN PLACE. ONE OR TWO WEAK WAVES
OF LOW PRESSURE MAY BRING A CHANCE OF SHOWERS FOR THE REGION. AN
APPROACHING FRONT WITH ASSOCIATED LOW PRESSURE LOOKS TO AFFECT
SOUTHERN NEW ENGLAND FRIDAY NIGHT AND SATURDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
130 PM UPDATE...
MORE OF THE SAME...MOISTURE CONTINUES TO STREAM OFF OF THE GULF OF
MAINE AS A WEAK DEFORMATION AXIS CONTINUES TO SPREAD RAINFALL FROM
CENTRAL CT INTO RI AND E MA. MOST OF THIS RAIN IS
LIGHT...GENERALLY ONLY A FEW HUNDREDTHS OR SO AN HOUR. THIS WILL
LIKELY BE THE CASE MOST OF THE EVENING AS WELL...THANKS TO THE
STRONGER DYNAMICS REMAINING OFFSHORE UNTIL THE EARLY MORNING
HOURS.

PREVIOUS DISCUSSION...
NORTHEASTERLY FLOW CONTINUES ALLOWING FOR AREAS OF
LOW CLOUDS... FOG...AND DRIZZLE THROUGH THE MORNING HOURS. AS THE
BOUNDARY LAYER STARTS TO MIX A BIT THOUGH...DRIZZLE SHOULD COME TO
AN END. A FEW STEADIER SHOWERS ARE POSSIBLE ACROSS RHODE ISLAND
AND SOUTHEASTERN MASSACHUSETTS LATER TODAY AS A WEAK SHORTWAVE
MOVES ACROSS SOUTHERN NEW ENGLAND. EXPECT TEMPERATURES TO BE ABOUT
5 DEGREES BELOW NORMAL.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
TONIGHT...EXPECTING ANOTHER NIGHT MUCH LIKE THE LAST WITH LOW 
PRESSURE WELL SOUTHEAST OF NANTUCKET.  AREAS OF LOW CLOUDS... 
FOG...AND DRIZZLE ARE LIKELY ONCE AGAIN WITH VERY MOIST AIR IN THE 
LOW LEVELS.  MORE WIDESPREAD SHOWERS ARE POSSIBLE ACROSS RHODE 
ISLAND AND SOUTHEASTERN MASSACHUSETTS AS THE MID LEVEL LOW PUSHES 
INTO SOUTHERN NEW ENGLAND.  OVERNIGHT LOWS WILL BE FAIRLY MILD 
THANKS TO THE LOW LEVEL HUMIDITY WITH MOST LOCATIONS REMAINING IN 
THE 50S.

WEDNESDAY...BEST SHOT OF SHOWERS AS MID LEVEL LOW MOVES OVER 
SOUTHERN NEW ENGLAND.  THESE WILL LIKELY BE LIMITED MAINLY TO 
SOUTHEASTERN MASSACHUSETTS AND RHODE ISLAND WHERE THE BEST LIFT 
EXISTS.  OTHERWISE...MORE OF THE SAME LOW CLOUDS...DRIZZLE...AND 
FOG. OVERCAST SKIES AND WET WEATHER WILL KEEP TEMPERATURES IN THE 
LOW TO MID 60S.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
BIG PICTURE... ALASKA SHORTWAVE DIGS OVER THE WESTERN USA/CANADA AND 
KICKS THE ESTABLISHED UPPER TROUGH EAST TO THE GREAT LAKES. THIS 
BRINGS A BROAD CYCLONIC FLOW OVER THE EASTERN USA WITH BELOW 
NORMAL HEIGHTS WHILE AN UPPER RIDGE BUILDS OVER THE WESTERN USA.

EMBEDDED IN THIS FLOW...A CLOSED LOW OVER NEW ENGLAND WEDNESDAY 
NIGHT MOVES OFF THROUGH THE MARITIMES THURSDAY AND FRIDAY.

THE DAILIES... 

WEDNESDAY NIGHT-THURSDAY... UPPER LOW OVER SOUTHERN NEW ENGLAND 
MOVES OFF TO THE EAST. LINGERING INSTABILITY UNDER THE COLD CORE 
SHOULD SUPPORT LINGERING SHOWERS WEDNESDAY NIGHT TAPERING OFF 
THURSDAY MORNING. CROSS SECTIONS SHOW PLENTY OF MOISTURE BELOW 600 
MB THROUGH THURSDAY MIDDAY FOLLOWED BY A DRYING TREND IN THE 
AFTERNOON. TEMPS AT THE TOP OF THE MIXED LAYER ARE EQUIV TO 850 MB 
TEMPS OF 2-5C...SUPPORTING MAX TEMPS IN THE LOW TO MID 60S. MOIST 
GROUND AND COOLING TEMPS THURSDAY NIGHT WILL ALLOW PATCHY FOG TO 
FORM ESPECIALLY OVER THE INTERIOR.

FRIDAY... HIGH PRESSURE BUILDS SOUTH OVER NEW ENGLAND. CROSS 
SECTIONS OF RH SHOW INCREASING CIRRUS-LEVEL MOISTURE BUT DRY THROUGH 
MOST OF THE COLUMN...INCREASING LOW LEVEL MOISTURE TOWARD EVENING. 
OVERALL...EXPECT A FAIR WEATHER DAY WITH LIGHT EAST TO SOUTHEAST 
WIND. TEMPS AT THE TOP OF THE MIXED LAYER WOULD SUPPORT MAX TEMPS IN 
THE MID AND UPPER 60S. THE EAST FLOW MAY KEEP COOLER TEMPS NEAR THE 
EAST MASS COAST.

FRIDAY NIGHT-SATURDAY... SHORTWAVE DRIVING AROUND THE DEEPENING 
EASTERN TROUGH PUSHES A COLD FRONT ACROSS THE MID ATLANTIC STATES 
FRIDAY NIGHT AND ACROSS NEW ENGLAND ON SATURDAY. THE SHORTWAVE AND 
THE SUPPORTING JET ENERGY SHOW SIGNS OF LIFTING THROUGH EASTERN NY 
AND VERMONT...BUT WITH POTENTIAL TO DIRECTLY AFFECT SOUTHERN NEW 
ENGLAND. ANOTHER CONCERN WOULD BE THE DRY PATTERN WE HAVE BEEN IN 
FOR SEVERAL WEEKS...THESE PATTERNS TEND TO MAINTAIN THEMSELVES EVEN 
WHEN FORECAST DATA SAYS OTHERWISE. AND A DAY 5 FORECAST IS RATHER 
FAR OUT TO SHOW GREAT CERTAINTY. WE WILL MAINTAINING CONTINUITY WITH 
POPS FROM THE PREVIOUS FORECAST AND WITH ADJOINING OFFICES...BUT OUR 
ACTUAL CONFIDENCE IS 15-20 PERCENT LOWER.

SUNDAY-MONDAY... HIGH PRESSURE BUILDS UP FROM THE SOUTH AND SHOULD 
PROVIDE DRY WEATHER MUCH OF THIS PERIOD. THE UPPER TROUGH CENTERED 
TO OUR WEST WILL BRING LOWER HEIGHTS OVER THE GREAT LAKES WHICH WILL 
MEAN COOLER TEMPS. TEMPERATURES HERE IN NEW ENGLAND SHOULD BE A 
LITTLE COOLER THAN NORMAL BUT EXPECT THE COLDEST TEMPS TO REMAIN 
WEST OF NEW ENGLAND WITH THE AXIS OF THE TROUGH. 

A SHORTWAVE MOVES THROUGH THE TROUGH ON MONDAY AND SOUTHERLY WINDS 
AHEAD OF THE SHORTWAVE WILL BRING HIGHER MOISTURE AIR OUR 
WAY...GENERATING SOME CLOUDS AND POSSIBLY SHOWERS. THESE 
CLOUDS/SHOWERS SHOULD HOLD UNTIL THE SHORTWAVE GETS 
CLOSER...PROBABLY MONDAY NIGHT.

&&

.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
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 IN EAST OF AN IJD-ORH-MHT LINE...WITH MVFR WEST. THIS
IS MAINLY DUE TO CIGS THROUGH EVENING...BUT AROUND 23Z AND AFTER
VSBYS MAY BEGIN TO DIP AS WELL IN A MIX OF DRIZZLE/FOG/LIGHT RAIN.
POSSIBILITY OF PERIODIC IFR VSBYS...BUT MAINLY VFR EXPECTED. 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...WEDNESDAY NIGHT THROUGH SATURDAY...

WEDNESDAY NIGHT-THURSDAY...CIGS/VSBYS AT MVFR/IFR IN LINGERING LOW 
CLOUDS AND FOG WEDNESDAY NIGHT AND THURSDAY MORNING. CONDITIONS 
SHOULD IMPROVE TO VFR THURSDAY AFTERNOON.  PATCHY IFR CIGS/VSBYS IN 
FOG AFTER MIDNIGHT THURSDAY NIGHT.

FRIDAY...VFR.

SATURDAY...CONDITIONS DIMINISHING TO MVFR IN SHOWERS AS A COLD FRONT 
MOVES THROUGH.  SOUTH WINDS LEAD THE COLD FRONT...WITH WINDS 
SHIFTING TO WEST AFTER THE FRONT MOVES THROUGH.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM...HIGH CONFIDENCE THROUGH WED.

PERSISTENT NORTHEASTERLY FLOW WILL RESULT IN BUILDING SEAS THROUGH 
THE PERIOD.  INCREASED WAVE WATCH GUIDANCE BY 20 PERCENT TO ACCOUNT 
FOR A GENERAL LOW BIAS IN THIS TYPE OF SCENARIO. SCA CONTINUES FOR 
THE NORTHEASTERN WATERS THROUGH THIS MORNING.  ALSO ISSUED SCA FOR 
SEAS ACROSS THE SOUTHERN AND SOUTHEASTERN OUTER WATERS FOR TONIGHT 
AND WEDNESDAY.

OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...MODERATE CONFIDENCE.

NORTHEAST WINDS WEDNESDAY NIGHT THROUGH FRIDAY WITH GUSTS NEAR 20 
KNOTS. WINDS SHIFT TO SOUTH SATURDAY AHEAD OF THE COLD FRONT...THEN 
SHIFT WEST AFTER THE COLD FRONT MOVES THROUGH. WIND GUSTS 20 TO 25 
KNOTS POSSIBLE ON SATURDAY. SEAS OF 5 TO 8 FEET LINGER ON THE 
EXPOSED WATERS THROUGH MUCH OF THE PERIOD.  EXPECT SMALL CRAFT 
ADVISORY ON AT LEAST THE EXPOSED WATERS FOR MUCH OF THE PERIOD. 

MAY EXPERIENCE A STORM SURGE OF 1 TO 1.5 FEET DURING MIDWEEK BUT
THE ASTRONOMICAL TIDES ARE NOT ALL THAT HIGH.

&&

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

&&

$$
SYNOPSIS...WTB/RLG
NEAR TERM...DOODY/RLG
SHORT TERM...RLG
LONG TERM...WTB
AVIATION...WTB/DOODY
MARINE...WTB/RLG



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