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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBOX 190720
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
320 AM EDT SUN MAY 19 2013

.SYNOPSIS...
-- Changed Discussion --
HIGH PRESSURE WILL MOVE OFFSHORE TODAY. A WARM FRONT WILL BRING A
FEW SHOWERS TO THE REGION TONIGHT AS IT CROSSES THE AREA. THE
FRONT IS EXPECTED TO STALL OVER CENTRAL NEW ENGLAND MONDAY. WARM
AND HUMID CONDITIONS ARE EXPECTED FOR MOST OF THE WEEK WITH SCATTERED
SHOWERS AND POSSIBLE THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON AND EVENING HOURS.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
320 AM UPDATE...

PLENTY OF MID/HIGH CLOUDS ACROSS SOUTHERN NEW ENGLAND THIS MORNING
BUT LOW CLOUD DECK OVER COASTAL ME/NH PUSHED BACK INTO
MANCHESTER...LAWRENCE AND BEVERLY. HIGH RES MODELS INDICATE THAT
IS ABOUT AS FAR S AS IT WILL GET BEFORE IT BEGINS TO PUSH
OFFSHORE BY MID MORNING.

STILL NOT SEEING MUCH IN WAY OF SHOWERS TO OUR SW AS ACTIVITY OVER
NJ IS PIVOTING OFFSHORE. HIGH RES MODELS ARE INSISTENT WE WILL
SEE DEVELOPMENT INTO HUDSON VALLEY AND CT BEFORE DAYBREAK.
RAP/HRRR BRING SHOWERS TO CT VALLEY BY 8 AM AND TO REST OF AREA
BEFORE NOON. NOT SEEING MUCH SUPPORT FOR THAT TO OCCUR BASED UPON
RADAR MOSAIC SO WE CONTINUED WITH SLOWER TREND SHOWN BY 00Z NAM...
NAMELY ANY SHOWERS HOLD OFF UNTIL THIS AFTERNOON. ANY RAINFALL IS
EXPECTED TO BE LIGHT.

TEMPS ARE A CHALLENGE TODAY WITH VARYING AMOUNTS OF CLOUD COVER.
SHOULD BE ABLE TO WARM QUICKLY THIS MORNING BEFORE SKIES CLOUD
OVER AREAWIDE THIS AFTERNOON. WE WILL CONTINUE TO SHOW WARMEST
TEMPS ACROSS RI/EASTERN MA /UPPER 60S/ AND USED A NAM/GFS MOS
BLEND AS CONFIDENCE IS MODERATE AT BEST.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
-- Changed Discussion --
WARM FRONT LIFTS THROUGH REGION TONIGHT ACCOMPANIED BY FEW SHOWERS.
DYNAMICS ARE NOT OVERLY STRONG AS MAIN FORCING MECHANISM APPEARS
TO BE MID LEVEL WARM ADVECTION...ESPECIALLY ACROSS CT/RI/SE MA
WHERE WE EXPECT GREATEST COVERAGE. MODELS DO SHOW MARGINAL
INSTABILITY AND MEAGER CAPE SO INCLUDED ISOLATED THUNDER...AGAIN
MAINLY FOR LOCATIONS CLOSER TO S COAST. HIGHER DEWPOINT AIR ON
S/SW WINDS SHOULD PROMOTE PATCHY FOG FORMATION.

ALTHOUGH FRONT REMAINS TO OUR N MON...CROSS SECTIONS SHOW PLENTY
OF LOWER LEVEL MOISTURE WHICH MEANS CLOUD COVER WILL BE TOUGH TO
BREAK...ESPECIALLY NEAR S COAST WHERE SW FLOW WILL MAINTAIN DEEPER
MARINE LAYER. MODELS DIFFER IN COVERAGE AND TIMING OF
PRECIPITATION...BUT IT APPEARS WE WILL SEE AT LEAST SCATTERED
SHOWERS/ISOLATED THUNDER ACROSS INTERIOR THROUGHOUT DAY.

EXPECT WARMER/MORE HUMID DAY BUT NOT QUITE SURE WE CAN REACH
LOWER 80S AS INDICATED BY GFS MOS. TONED BACK A BIT BY BLENDING
NAM MOS AND 2M TEMPERATURES WHICH YIELDS HIGHS IN MID-UPPER 70S
EXCEPT 60S AROUND CAPE COD/ISLANDS WITH ONSHORE FLOW.
-- End Changed Discussion --

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
-- Changed Discussion --
HIGHLIGHTS...

*  WARM AND HUMID WITH SCATTERED SHOWERS THRU AT LEAST THU

OVERVIEW AND MODEL PREFERENCES...
18/12Z LONG RANGE GUIDANCE SUITE IS IN FAIR AGREEMENT THROUGH THE
MID TERM PERIOD...BUT THEN STRUGGLES WITH THE MERGING /OR NON-
MERGING/ OF A SPLIT FLOW REGIME TOWARD THE END OF THE PERIOD.
GIVEN THE AGREEMENT THAT THE CONVERGENT REGION OF THESE TWO
STREAMS WILL DOMINATE THROUGH THE MID TERM...WILL USE A GFS/ECMWF
BLEND TO BASELINE FORECAST. FOR THE TAIL END OF THE LONG
TERM...WILL LIKELY LEAN AWAY FROM THE ECMWF DETERMINISTIC RUN...AS
IT GENERATES A VERY DEEP MEANDERING CUTOFF IN NRN NEW ENGLAND
WHICH WOULD SUGGEST THAT UNSETTLED CONDITIONS CONTINUE WELL INTO
/AND POSSIBLY BEYOND/ THE WEEKEND. IN ANY CASE...WITH CONVERGENT
STREAMS ALOFT THROUGH THE MID TERM...UNSETTLED CONDITIONS ARE
LIKELY...BUT AS WAS NOTED...IT SHOULD NOT BE A WASHOUT.

DETAILS...

MON NIGHT...
SFC WARM FRONT SHIFTS INTO NRN NEW ENGLAND WITH TIME...ALLOWING
MUCH OF SRN NEW ENGLAND TO BREAK INTO THE WARM SECTOR THROUGH THE
PERIOD. LOOKS LIKE A FAIR AMOUNT OF MOISTURE WILL COMBINE WITH
DIURNAL HEATING TO YIELD SOME DAYTIME -SHRA...PARTICULARLY OVER
SRN NH AN NRN MA. SOUNDINGS LOOK TO REMAIN FAIRLY STABLE DURING
THE DAY...SO WILL KEEP THUNDER OUT OF THE FORECAST FOR NOW. WITH
HIGH TEMPS IN THE UPPER 60S TO NEAR 70 AND DWPTS IN THE UPPER
50S...CONDITIONS ARE LIKELY TO FEEL MUGGY.

TUE INTO WED...
THE WARM FRONT IN NRN AND CENTRAL NEW ENGLAND IS EXPECTED TO
GRADUALLY SINK S OF THE REGION THROUGH THE PERIOD. ON TUE...THIS
FRONTAL PASSAGE /PARTICULARLY DURING THE AFTERNOON HEAT/ EXPECT
SOME DESTABILIZATION...ESPECIALLY IF THERE ARE SOME EARLY DAY
CLOUD BREAKS AS SOME OF THE GUIDANCE SUGGESTS. COOLING UPPER LVLS
AS HIGH PRES NOSES IN FROM THE N SUGGEST A RISE IN K/TT AND LI/S
DIPPING TO 0 TO NEGATIVE VALUES. SHEAR IS NOT
GREAT...PARTICULARLY THROUGH H85...BUT THERE IS ENOUGH SUPPORT FOR
UPDRAFTS...SO WILL CONTINUE TO SUGGEST THUNDER FOR TUE. ON
WED...WEAK EARLY DAY RIDGING WILL LIKELY YIELD A PARTLY CLOUDY
START TO THE DAY UNTIL RETURN FLOW DEVELOPS AS HIGH PRES SLIDES TO
THE NE. GIVEN THE APPROACHING SHORTWAVE...EARLY CLEARING AND
INCREASING MOISTURE...MAY SEE ANOTHER DAY WITH THE THREAT FOR
TSTMS...ESPECIALLY IN THE W AS A SECONDARY WARM FRONT MOVES
THROUGH THE AREA. A LITTLE BETTER SHEAR ON WED TOO POSSIBLY...SO
WILL CONTINUE WITH A THUNDER THREAT ON WED AS WELL.

THU AND FRI...
TRICKY FORECAST HERE AS IT WILL BE DEPENDENT ON HOW QUICKLY NRN
STREAM JET ENERGY SINKS S FROM QUEBEC AND ONTARIO. THIS WILL
DICTATE HOW QUICKLY A SERIES OF SHORTWAVES AND THEIR SFC LOW PRES
WAVES WILL AFFECT THE REGION. IN ANY CASE...THE WET WX CONTINUES
ALTHOUGH A BIT MORE STABLE THAN TUE AND WED. GIVEN THE DIFFERENCES
BETWEEN MODELS IN HOW THE NRN STREAM WORKS OUT...EXACT TIMING FOR
ANY OF THESE WAVES REMAINS A BIT OF A QUESTION MARK. ONCE
AGAIN...IT WILL LIKELY NOT RAIN EVERYDAY...BUT THERE IS THE THREAT
FOR AT LEAST -SHRA THROUGH THE PERIOD.

THE WEEKEND...
THE SRN STREAM RIDGE BEGINS TO MOVE THE NRN STREAM LONGWAVE TROF
OFFSHORE THROUGH THE PERIOD...SO LOOKS LIKE A TRANSITION TO MORE
DRY WX WILL BE LIKELY SOMETIME DURING THE WEEKEND.
-- End Changed Discussion --

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
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FORECASTER CONFIDENCE LEVELS...

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

OVERVIEW...HIGH CONFIDENCE.

IFR CIGS ALONG ME/NH COAST AND INTO MHT/LWM ARE NOT EXPECTED TO
DROP MUCH FARTHER S EARLY THIS MORNING...AND SHOULD ERODE TOWARD
DAYBREAK AS THIS DECK OF LOW CIGS BEGINS TO PUSH OFFSHORE.
OTHERWISE VFR CIGS AOA 080 EXPECTED THIS MORNING...BEFORE SLOWLY
LOWERING TO MVFR THIS AFTERNOON FROM SW TO NE.

S/SW GRADIENT REMAINS WEAK BUT SEA BREEZES SHOULD BE LIMITED TO S
COAST TODAY. DOES NOT APPEAR FAVORABLE ALONG E MA COAST BUT IF IT
WERE TO OCCUR IT WOULD BE EARLY THIS AFTERNOON.

FAIRLY CONFIDENT ON PERIOD OF SHOWERS LATE THIS AFTERNOON BAF/BDL
WHICH SHIFTS TO RI/MA COASTS THIS EVENING. SHOWERS WILL BE MOST
NUMEROUS NEAR S COAST TONIGHT...WHERE ISOLATED THUNDER IS ALSO
POSSIBLE.

ALTHOUGH SHOWERS EXIT BEFORE DAYBREAK...ADDITIONAL SHOWERS/
THUNDER MAY REDEVELOP DURING DAY TUE AS WARM FRONT LIFTS TO OUR N.
APPEARS COVERAGE WILL BE SCATTERED AT BEST...WITH INTERIOR
SOUTHERN NEW ENGLAND HAVING BEST CHANCE.

KBOS TERMINAL...HIGH CONFIDENCE IN TAF. IFR CIGS EXPECTED TO
REMAIN N OF AIRPORT /LWM-BVY/ EARLY THIS MORNING AND INCLUDED
FEW008 AS A HEADS UP. NOT CONFIDENT SEA BREEZE WILL OCCUR BUT IF
IT DOES IT WOULD BE 16Z-19Z.

KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. MVFR CIGS POSSIBLE
PRIOR TO 12Z BUT NOT CONFIDENT IT WILL OCCUR GIVEN HIGHER CIGS
ACROSS NYC METROS.

OUTLOOK...TUESDAY THROUGH THURSDAY...

MODERATE CONFIDENCE THROUGH THE PERIOD.

MAINLY VFR/MVFR DURING THE DAYS...WITH THE BEST CHANCE FOR MVFR IN
ANY DAYTIME SHOWERS OR OCCASIONAL THUNDERSTORMS. EXPECT MAINLY
MVFR/IFR DURING THE OVERNIGHT HOURS IN A MIX OF FOG AND LOW
STRATUS...ESPECIALLY CLOSER TO THE SOUTH COAST.

IN SUM...A PERIOD OF UNSETTLED WX IS EXPECTED THROUGH THE PERIOD.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS...

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

HIGH CONFIDENCE THROUGH MON.

HIGH PRESSURE MOVING OFFSHORE WILL MAINTAIN LIGHT WINDS/FLAT SEAS
TODAY. COULD SEE FEW LIGHT SHOWERS LATER THIS AFTERNOON AS WARM
FRONT APPROACHES.

INCREASING S/SW FLOW DEVELOPS TONIGHT AND MON AS WARM FRONT LIFTS
INTO CENTRAL NEW ENGLAND. THIS WILL BRING SLOWLY BUILDING SEAS TO
OUTER WATERS WHERE CURRENT SCA HAS BEEN EXTENDED INTO MON. ADDED
RI/BLOCK IS SOUNDS TO SCA AS WELL...AND BUZZARDS BAY/VINEYARD
SOUND WHERE SW WINDS WILL CREATE STEEP WAVES DURING TIMES OF
DEPARTING TIDE /HIGH TIDE 355 AM AND 437 PM MON AT NEW BEDFORD/.

SHOULD ALSO SEE PERIOD OF SHOWERS/ISOLATED THUNDER TONIGHT AND
MORE WIDELY SCATTERED ACTIVITY MON. PATCHY DENSE FOG PROBABLE
AROUND CAPE COD AND ISLANDS.

OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...

MODERATE CONFIDENCE THROUGH THE PERIOD.

WINDS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS THROUGH
THE PERIOD. ALSO...A COMBINATION OF SHOWERS AND FOG WILL LIKELY
LEAD TO REDUCTIONS IN VISIBILITIES THROUGH THE PERIOD.

MON NIGHT INTO TUE...LINGERING SWELL ALONG THE SRN WATERS AND ERN
OUTER WATERS GRADUALLY SUBSIDES THROUGH TUE. WILL LIKELY NEED
SMALL CRAFT ADVISORY FOR SEAS INTO THE DAY TUE.

WED AND WED NIGHT...SEAS REMAIN BELOW SMALL CRAFT THRESHOLDS.

THU...AS LOW PRES APPROACHES FROM THE W. EXPECT GRADUALLY BUILDING
SEAS...WHICH MAY REACH 5-7 FT DURING THE DAY THU. SMALL CRAFT
ADVISORIES MAY BE NEEDED AGAIN.
-- End Changed Discussion --

&&

.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 TO 7 PM EDT
     MONDAY FOR ANZ233>235-237.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 AM TO 7 PM EDT
     MONDAY FOR ANZ254-255.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 5 PM THIS
     AFTERNOON TO 7 PM EDT THIS EVENING FOR ANZ256.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM MIDNIGHT TONIGHT
     TO 7 PM EDT MONDAY FOR ANZ256.
-- End Changed Discussion --

&&

$$
SYNOPSIS...JWD/THOMPSON
NEAR TERM...JWD
SHORT TERM...JWD
LONG TERM...DOODY
AVIATION...JWD/THOMPSON
MARINE...JWD/THOMPSON