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000
FXUS61 KBOX 191958
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
358 PM EDT SUN MAY 19 2013

.SYNOPSIS...
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A WARM FRONT WILL CROSS THE AREA OVERNIGHT WITH SHOWERS...AND THEN
STALL IN THE VICINITY OF SOUTHERN NEW ENGLAND THROUGH MONDAY
NIGHT. THE FRONT WILL MOVE THRU SOUTHERN NEW ENGLAND TUE.
SCATTERED SHOWERS AND POSSIBLE THUNDERSTORMS ARE ANTICIPATED TUE
THRU THU. A COOLER AND LESS HUMID AIR MASS IS EXPECTED FOR THE
COMING WEEKEND.
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&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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BAND OF WARM ADVECTION SHOWERS CONTINUE TO MOVE E THROUGH THE
REGION THIS AFTERNOON. CURRENTLY...THIS BAND IS LINED FROM SW NH
INTO SRN RI...AND MAKING SLOW PROGRESSION TO THE E. THE PRIMARY
REGION FOR THE SLOW MOVEMENT E HAS BEEN THE NEAR 15-20F DEWPOINT
DEPRESSION WHICH HAS BEEN DIFFICULT TO OVERCOME. ALL
SOUNDINGS...INCLUDING THE LAPS IN THE E...SHOW THE COLUMN MOISTURE
LOADING FROM THE TOP DOWN THROUGH THE EVENING...SO SUSPECT THESE
-SHRA WILL BE EVERYWHERE BY THE TIME THE SUN SETS.

THE SFC WARM FRONT ASSOCIATED WITH THESE -SHRA IS CURRENTLY
SLIDING IN FROM THE W...SO EXPECT THAT THE THREAT FOR -SHRA WILL
LINGER WELL INTO THE OVERNIGHT HOURS AS THIS FRONT MAKES ITS SLOW
PASSAGE. NOT EXPECTING MUCH IN THE WAY OF QPF WITH THIS BUT MOST
LOCATIONS HAVE DAMP GROUND BY DAYBREAK. THE ADDED MOISTURE IN THE
COLUMN /SOUNDINGS SUGGEST 1.0-1.5 INCHES PWAT BY 12Z/ WILL LEAD TO
A FAIR AMOUNT OF CLOUDS AND FOG AFTER THE -SHRA COME TO AN END
DURING THE EARLY MORNING HOURS. LOW CONFIDENCE IN WIDESPREAD DENSE
FOG...BUT A FEW SPOTS MAY DIP TO NEAR 1/4 MILE OR LESS AT TIMES.

THE WARM FRONT WILL STALL SOMEWHERE IN THE VICINITY OF NH BY THE
EARLY MORNING HOURS...SO SUSPECT THAT MUCH OF SRN NEW ENGLAND WILL
BE IN THE WARM SECTOR BY 12Z. ALSO...WITH SOME WEAK MID LVL
RIDGING WITHIN THIS WARM SECTOR...COULD ACTUALLY SEE SOME BREAKS
OF EARLY MORNING SUN ESPECIALLY AWAY FROM THE S AND E COASTS WHERE
STRATUS LINGERS.
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&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
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TOMORROW...
SFC WARM FRONT REMAINS ENTRENCHED ACROSS NH AND CENTRAL NEW
ENGLAND THROUGH MUCH OF THE DAY...ALLOWING SRN NEW ENGLAND INTO
THE WARM SECTOR. WITH THE ACTUAL BOUNDARY TO THE N...AFTER SOME
EARLY MORNING FOG/STRATUS IS ALLOWED TO BURN OFF...SOME BREAKS OF
SUN ARE POSSIBLE THROUGH ABOUT MID DAY. THIS WILL HAVE TO BE
MONITORED SINCE WITHIN THE WARM SECTOR SFC DWPTS SHOULD REACH
+15-18C AND TEMPS INCREASING TO THE UPPER 70S TO AROUND 80F IN
SPOTS ESPECIALLY IF THE SUN DOES SHINE THROUGH. WHILE FORCING
MECHANISMS ARE MINIMAL AT BEST...GUIDANCE DOES SUGGEST THE FRONT
MAKES A SLOW SLIDE TO THE S DURING THE DAY. WITH WARM-HUMID
AIRMASS IN PLACE...SFC LI VALUES DIP TO 0 TO -3 WITH ABOUT
500-1000 J/KG OF SB CAPE TO WORK WITH. THEREFORE...MAY SEE A
THREAT FOR SOME DAYTIME T-STORMS ESPECIALLY AWAY FROM THE S
COAST...WHERE SLY MARINE FLOW AND EARLY DAY STRATUS WILL KEEP
TEMPS DOWN...INCREASING STABILITY. GIVEN THIS...HAVE SOME CHANCE
POPS FOR THUNDER IN THE INTERIOR DURING THE AFTERNOON HOURS. SHEAR
IS MINIMAL GIVEN THE WEAK RIDGING FLOW ALOFT...AND NORMALIZED CAPE
IS QUITE LOW SUGGESTING SKINNY PROFILE...SO HEAVY RAIN APPEARS TO
BE THE PRIMARY THREAT WITH ANY STORMS AND WILL INCLUDE THAT WITH
WX FOR THIS UPDATE.

MON NIGHT...
WARM FRONT CONTINUES SLOW MIGRATION OVER SRN NEW ENGLAND THROUGH
THE OVERNIGHT HOURS...BUT WILL LIKELY ONLY HANG SOMEWHERE THROUGH
CENTRAL PORTIONS OF THE CWA BY 12Z TUE. THEREFORE...WITH DIURNAL
HEATING EARLY...MAY SEE LINGERING -SHRA/TSTMS INTO THE EVENING
HOURS UNTIL THE COLUMN IS ABLE TO STABILIZE. WITH SOME DRIER AIR
FILTERING BEHIND THE FRONT TO THE N...MAY ACTUALLY SEE PRECIP COME
TO AN END DURING THE OVERNIGHT HOURS. HOWEVER...WITH HIGH DWPT AIR
HANGING IN THE WARM SECTOR NEAR THE S COAST...A RETURN TO
FOG/STRATUS IS LIKELY ONCE AGAIN. EXPECT THAT OVERNIGHT MINS WILL
REMAIN IN THE UPPER 50S TO LOW 60S WITH A FAIR AMOUNT OF CLOUD
COVER EVEN IF THE PRECIPITATION DOES COMPLETELY CEASE.
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&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
HIGHLIGHTS...

HIGHLIGHTS...
* BACKDOOR COLD FRONT WILL REDUCE HUMIDITY AND CHANCE FOR SHOWERS/TSTMS
  EAST OF THE CT RIVER VALLEY ON TUE
* WARM AND HUMID WITH SCATTERED SHOWERS AND POSSIBLE TSTMS WED AFTERNOON
  THRU AT LEAST THU NIGHT
* COOLER AND DRIER AIR EXPECTED FOR THE COMING WEEKEND

MEDIUM RANGE MODELS PAINT A CONSISTENT SYNOPTIC SCALE PICTURE FOR
TUE THRU THU BUT STILL DIFFICULT TO RESOLVE TIMING AND
DISTRIBUTION OF SHORT WAVE ENERGY. BOTH 00Z GFS AND 00Z ECMWF
MODELS SUGGEST A BACKDOOR INTRUSION OF DRY AIR ON TUE INTO WED
MORNING THRU ALL EXCEPT POSSIBLY THE CT RIVER VALLEY. THE FRONT
LIFTS BACK NE DURING WED AFTERNOON. THUS FOR TUE WILL RELEGATE
CHANCE SHOWERS/TSTMS JUST TO SW ZONES. THEN THE ECMWF AND GFS
OPERATIONAL RUNS AND THE PRIOR RUN ENSEMBLES DIVERGE ON CHARACTER
OF EASTERN TROF THAT WILL FLUSH OUT THE AIR MASS LATE IN THE WEEK.
THE ECMWF HAS BEEN CONSISTENTLY SHOWING A CONSOLIDATED NORTHERN
STREAM TROF DRIVING A COLD FRONT THRU THU NIGHT/EARLY FRI MORNING.
THE GFS OPERATIONAL RUN AND ENSEMBLE MEAN KEEP A NOTABLE CHUNK OF
ENERGY SOUTH OF THE MAIN STREAM NORTHERN FLOW AND RESULTS IN THE
SPIN UP OF A SFC LOW OFF THE MID ATLC COAST AND WET DAY FOR MUCH
OF THE FORECAST AREA ON FRI.

TUE-WED...WILL INDICATE SCT SHOWERS AND WIDELY SCT TSTMS DURING
THIS PERIOD WITH HIGHEST POPS DURING THE DIURNALLY FAVORED
AFTERNOON/EVENING PERIOD AND SW OF A EEN-ORH-EWB LINE GIVEN THE
POTENTIAL FOR A BACKDOOR AIR MASS TO EASE INTO OUR NE ZONES.

THE TREND FOR BOTH THE GFS AND ECMWF MODELS TO BRING A BACKDOOR
INTRUSION OF DRY AIR INTO THE REGION ON TUE LENDS GREATER
CONFIDENCE THAT ANY SHOWER ACTIVITY TUE WILL LIKELY BE RESTRICTED
TO THE CT RIVER VALLEY AREA. HAVE ALSO LOWERED DEWPOINTS. ONSHORE
FLOW WILL KEEP TEMPS COOLER ALONG THE E COAST. THUS FOR EASTERN MA
AND RI TUE NO LONGER LOOKS TO BE A WARM AND HUMID DAY.

WED...THE WARM AND HUMID AIR MASS ADVANCES BACK NE AND SO DOES
THE RISK OF SCT SHOWERS AND WIDELY SCT TSTMS IN THE AFTERNOON AND
EARLY EVENING.

THU...RELATIVELY STRONG SHORT WAVE TROF AND COLD FRONT WILL BE
APPROACHING FROM THE WEST LATE IN THE DAY. ANTICIPATING RELATIVELY
UNSTABLE AIR MASS AND INCREASING VERTICAL SHEAR THU AFTERNOON AND
EVENING. IT IS POSSIBLE THAT WE MAY EXPERIENCE A FEW STRONG/SEVERE
TSTMS LATE THU AFTERNOON AND EVENING...MOST LIKELY WESTERN HALF OF
AREA GIVEN THE TIMING OF THE SHORT WAVE AND FRONT. RAISED POPS TO
HIGH CHANCE LATE THU AND THU NIGHT.

FRI...HAVE RELATIVELY LOW CONFIDENCE FOR THIS DAY DUE TO MODEL
DISPARITY IN HANDLING THE CONFIGURATION OF THE EASTERN TROF
ENERGY. FOR NOW...PLAN TO HAVE SHOWERS INTO AT LEAST FRI MORNING
FOR MOST LOCATIONS AND PERHAPS HAVE A CHANCE OF SHOWERS THAT
PERSIST OVER THE SE ZONES...OR AT LEAST THE CAPE AND ISLANDS...TO
PERSIST TO AT LEAST FRI EVENING. IN ESSENCE AM LEANING TOWARD
ECMWF SOLUTION WHICH HAS REMAINED RELATIVELY CONSISTENT AND SEEMS
TO BE FAVORED BY WPC. THE GFS HAS...HOWEVER...BEEN FAIRLY
CONSISTENT IN ITS SOLUTION AND THE OPERATIONAL RUN IS SUPPORTED BY
ITS ENSEMBLES SO CANNOT COMPLETELY RULE THAT OUT. IF INDEED A
SURFACE LOW WERE TO DEVELOP AS ADVERTISED BY THE GFS...WE COULD
SEE WINDS APPROACHING MARGINAL GALES ON THE WATER AND A RISK FOR
SOME COASTAL FLOODING WITH THE LATE FRI EVENING HIGH TIDE...WHICH
IS QUITE HIGH ASTRONOMICALLY TO BEGIN WITH. THAT DOES NOT SEEM TO
BE THE MOST LIKELY SOLUTION AT THIS TIME BUT WILL NEED TO KEEP AN
EYE ON IT.

SAT...MODERATE TO HIGH CONFIDENCE OF A COOL DRY AIR MASS
DOMINATING THE REGION.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
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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 THE AFTERNOON...LOWER CONFIDENCE IN TIMING
OF MVFR/IFR DURING THE OVERNIGHT HOURS.

MAINLY VFR SAVE FOR IN AN AREA OF -SHRA IN WRN MA AND CENTRAL CT.
THIS BAND OF -SHRA AND MVFR CIGS WILL GRADUALLY SHIFT TO THE E
INTO THE EVENING. NOT CONFIDENT IN EXACT TIMING...BUT THE TAF
TREND REPRESENTS THE ROUGH TIMING OF BOTH -SHRA ONSET AND MVFR.
MAY SEE SOME MVFR/IFR FOG AS THE -SHRA MOVES OUT AFTER 06Z AT MANY
OF THE TERMINALS. SOME IMPROVEMENT TO VFR IS POSSIBLE EARLY
MON...ESPECIALLY AWAY FROM THE S COASTAL TERMINALS. AN ISOLATED
THUNDERSTORM IS ALSO POSSIBLE OVERNIGHT...AND AGAIN DURING THE
AFTERNOON MON.

KBOS TERMINAL...OVERALL HIGH CONFIDENCE IN THE TAF TRENDS...BUT
LOWER CONFIDENCE IN EXACT TIMING. SEA BREEZE CONTINUES INTO EARLY
EVENING HOURS...WITH THE POSSIBILITY OF SOME BKN LOW STRATUS.
EXPECT MVFR IN -SHRA AND FOG DURING THE OVERNIGHT HOURS WITH SOME
IMPROVEMENT MON MORNING. LOW PROBABILITY OF AN ISOLATED RUMBLE OF
THUNDER TONIGHT AND AGAIN TOMORROW AFTERNOON.

KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. MVFR WILL LIKELY
DOMINATE INTO THE OVERNIGHT HOURS...WITH SOME IMPROVEMENT
FOLLOWING SOME -SHRA/FOG OVERNIGHT. THE BEST CHANCE FOR MVFR WILL
BE DURING THE MORNING MON. LOW PROBABILITY OF AN ISOLATED T-STORM
OVERNIGHT AND AGAIN MON.

OUTLOOK...TUESDAY THROUGH FRIDAY...

MODERATE CONFIDENCE THROUGH THE PERIOD.

TUE...SCT MVFR CIGS/VSBYS IN SCT SHOWERS AND ISOLD TSTMS CT
VALLEY...VFR ELSEWHERE.

WED...AREAS OF MVFR CIGS/VSBYS IN SCT SHOWERS AND WIDELY SCT
TSTMS.

THU...MVFR CIGS/VSBYS WITH FOG AND STRATUS IN THE MORNING
AND THEN AGAIN IN THE AFTERNOON WITH SCT SHOWERS AND TSTMS.
POSSIBLY A FEW STRONG TSTMS LATE THU AFTERNOON/EVENING.
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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 MON NIGHT.

A WARM FRONT CROSSES THE WATERS TONIGHT WITH A MIX OF SHOWERS AND
POTENTIALLY DENSE FOG /PARTICULARLY OVER THE SRN WATERS/ WHICH
WILL REDUCE VISIBILITIES AT TIMES. THE FRONT STALLS NORTH OF THE
WATERS DURING THE DAY MONDAY.

WINDS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT THRESHOLDS THROUGH
THE PERIOD. HOWEVER...WITH LONG-FETCH AND PERSISTENT S FLOW...A
S-SW SWELL WILL BUILD DURING THE OVERNIGHT HOURS ON S COASTAL
WATERS...REACHING 5-7 FT AT TIMES. THIS SWELL IS EXPECTED TO
LINGER UNTIL MON NIGHT. THEREFORE...SMALL CRAFT ADVISORY FOR SEAS
REMAINS IN PLACE.

OUTLOOK...TUESDAY THROUGH FRIDAY...

MODERATE CONFIDENCE THROUGH THE PERIOD.

A LEFT OVER SWELL AT OR A LITTLE ABOVE 7 FT LIKELY TUE...SUBSIDING
WED. BUILDING SEAS LIKELY THU AS SW FLOW STRENGTHENS. AREAS OF
FOG LIKELY WED NIGHT THRU THU. WINDS MAY APPROACH SCA LEVELS LATE
THU AND THU NIGHT.
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&&

.BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 6 AM MONDAY TO 2
     AM EDT TUESDAY FOR ANZ233>235-237.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 AM MONDAY TO 8
     AM EDT TUESDAY FOR ANZ254-255.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM MIDNIGHT TONIGHT
     TO 8 AM EDT TUESDAY FOR ANZ256.
-- End Changed Discussion --

&&

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