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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBOX 230635
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
235 AM EDT THU MAY 23 2013

.SYNOPSIS...
-- Changed Discussion --
A STALLED FRONT ACROSS CENTRAL SOUTHERN NEW ENGLAND WILL MOVE
NORTH AS A WARM FRONT LATER TODAY. EXPECT WARM...HUMID AND
SHOWERY WEATHER TO CONTINUE INTO SATURDAY. SCATTERED STRONG
THUNDERSTORMS ARE POSSIBLE TODAY AND FRIDAY. A COLD FRONT WILL BE
SLOW TO CLEAR...SO SHOWERS MAY LINGER INTO SUNDAY. COOLER AND
LESS HUMID CONDITIONS SHOULD MOVE IN FOR THE HOLIDAY INTO NEXT
WEEK.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TODAY/...
-- Changed Discussion --
2 AM UPDATE...STILL RATHER TRANQUIL ACROSS SOUTHERN NEW ENGLAND IN
COMPARISON. LOTS OF STRATUS WITH AREAS OF POOR VISIBILITY IN FOG
AND DRIZZLE TO CONTEND WITH. A FRONTAL BOUNDARY STILL LOOKS TO BE
STALLED ALONG I-90 IN MA. 23/00Z GUIDANCE HAS STRUGGLED WITH THE
MOVEMENT OF THIS FRONT...AND THINK THE GUIDANCE IS TOO QUICK TO
PUSH THIS FRONT NORTH. ADJUSTED THE TIMING OF THIS FRONT BASED ON
OBSERVED TRENDS FOR THIS MORNING. CURRENT EXPECTATION IS THIS
FRONT WILL PUSH NORTH QUICKLY THIS MORNING AFTER SUNRISE.

OTHERWISE...EXPECTING A LOW PRESSURE TO MOVE THROUGH THE GREAT
LAKES INTO THE SAINT LAWRENCE RIVER VALLEY TODAY. A BLEND OF THE
23/00Z GFS AND NAM LOOKS LIKE A GOOD SOLUTION FOR TIMING OF THIS
FEATURE. THIS SHOULD LEAVE SOUTHERN NEW ENGLAND IN THE WARM SECTOR
OF THIS LOW FOR MOST OF TODAY. INSTABILITY SHOULD BE LIMITED BY
THE COPIOUS CLOUDS TO START THE DAY...WITH SOME BREAKS POSSIBLE
THIS AFTERNOON. MODEST LOW-LEVEL WINDS COULD PROVIDE ENOUGH
ORGANIZATION WHERE SOME SEVERE THUNDERSTORMS ARE POSSIBLE...MUCH
LIKE THE PAST COUPLE OF DAYS. AREAS ACROSS THE WESTERN HALF OF
SOUTHERN NEW ENGLAND WILL BE MORE AT RISK FOR ANY SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING.

TEMPERATURES WERE A BLEND OF THE VARIOUS MOS PRODUCTS. DID ADJUST
TEMPERATURE TRENDS IN THE NEAR-TERM TO GO ALONG WITH SLOWER TIMING
OF WARM FRONT.
-- End Changed Discussion --

&&

.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
-- Changed Discussion --
A SLOW-MOVING COLD FRONT SHOULD PLOD ITS WAY EAST ACROSS SOUTHERN
NEW ENGLAND TONIGHT INTO FRIDAY. WIDESPREAD SHOWERS ARE A NEAR
CERTAINTY. A PLUME OF PRECIPITABLE WATER VALUES BETWEEN 1.50-1.75
INCHES AHEAD OF THIS FRONT SHOULD ALSO MEAN LOCALLY HEAVY
DOWNPOURS AS WELL. ENOUGH INSTABILITY TO KEEP A MENTION OF
ISOLATED TO SCATTERED THUNDERSTORMS IN THE FORECAST THROUGH THIS
PERIOD.

USED A BLEND OF THE SLOWER 23/00Z NAM AND THE SLIGHTLY FASTER 23/00Z
GFS FOR THE TIMING OF THIS COLD FRONT. THIS WAS ALSO SUPPORTED
FAIRLY WELL BY THE 22/21Z SREF.

TEMPERATURES WERE A BLEND OF THE VARIOUS MOS PRODUCTS.
-- End Changed Discussion --

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
-- Changed Discussion --
HIGHLIGHTS...

* SHOWERS AND THUNDERSTORMS FRIDAY AND SATURDAY
* UNSETTLED WEATHER CONTINUES SUNDAY...THEN SLOWLY IMPROVING
  MONDAY
* DRY BUT COOL CONDITIONS INTO THE MIDDLE OF NEXT WEEK

OVERVIEW AND MODEL PREFERENCES...

NOTING A MAJOR PATTERN CHANGE ACROSS THE LOWER 48 AS SEEN ON THE
LAST FEW OP RUNS OF THE GFS...ECMWF AND...TO A LESSER DEGREE...THE
UKMET. MODELS SIGNALING DIGGING UPPER TROUGH/CUTOFF LOW PRES
MOVING INTO THE WESTERN U.S. WHICH BUILDS A LARGE RIDGE OVER THE
PLAINS STATES...THEN IN TURN DIGS ANOTHER TROUGH MOVING OUT OF THE
GREAT LAKES TO THE EASTERN SEABOARD. LOOKS LIKE H5 CUTOFF LOW
FORMS BY SATURDAY ALONG THE MID ATLC COAST...SLOWING THE
PROGRESSION OF THE COLD FRONT ACROSS NEW ENGLAND INTO THE WEEKEND
AT LEAST. SOME TIMING ISSUES WITH THE EXIT OF THE SYSTEM...MAINLY
DUE TO HOW MUCH THE UPPER SYSTEM DIGS AS WELL AS POSSIBLE NEGATIVE
TILTING OF THE TROUGH.

AT THIS POINT...LEANED TOWARD THE WPC GUIDANCE SOLUTION WHICH USED
MAINLY MODEL ENSEMBLES...THEN BLENDED IN THE 12Z GFS/00Z ECMWF
WHICH WAS MORE AGGRESSIVE IN KEEPING INCLEMENT CONDITIONS GOING
THROUGH A GOOD PORTION OF THE UPCOMING HOLIDAY WEEKEND. DUE TO
TIMING OF THE EXIT OF THE UPPER SYSTEM...CONFIDENCE IS LOWER FOR
TRANSITION TIME /FOR NOW...DURING SUNDAY/. CONDITIONS LOOK TO
IMPROVE AS HIGH PRES BUILDS OUT OF CENTRAL CANADA FOR MON THROUGH
NEXT WED.

DETAILS...

FRIDAY NIGHT-SATURDAY...AS THE UPPER TROUGH DIGS ACROSS THE
APPALACHIANS AND EVENTUALLY DEVELOPING H5 CUTOFF LOW OVER THE MID
ATLC...THIS WILL SLOW THE PROGRESSION OF THE COLD FRONT ACROSS THE
REGION DURING THIS TIMEFRAME.

PW VALUES WILL STILL BE AROUND 1.5 INCHES...SO HEAVY DOWNPOURS
STILL POSSIBLE AS WELL AS GUSTY WINDS AND EVEN SMALL HAIL. CAN NOT
RULE OUT SOME THUNDER EVEN DURING THE NIGHTTIME HOURS. COOLER AIR
STARTS TO WORK INTO WESTERN AREAS AS THE LOW SLOWLY MOVES E TOWARD
SE MA AND THE CAPE SAT.

DEPENDING UPON WHETHER CLOUDS BREAK ACROSS W MA/SW NH...TEMPS MAY
FALL BACK TO THE UPPER 30S...OTHERWISE LOWS SAT NIGHT WILL FALL TO
THE 40S.

SUNDAY...FOR NOW...THIS APPEARS TO BE THE TRANSITION DAY AS LOW
PRES SLOWLY MOVES NE TO THE MAINE COAST. WILL STILL SEE SCT
SHOWERS ACROSS S NH/N MA EARLY...THEN SHOULD EXIT. HOWEVER...
RATHER LOW CONFIDENCE AS THIS DEPENDS UPON MOVEMENT OF THE UPPER
TROUGH OFF THE EASTERN SEABOARD AND ITS CUTOFF SYSTEM.

MONDAY THROUGH WEDNESDAY...EXPECT HIGH PRES TO BUILD OUT OF
CENTRAL CANADA DOWN THE EASTERN SEABOARD. TEMPS WILL BE COOL ON
THE HOLIDAY...THEN WILL REBOUND TO SEASONAL LEVELS AS THE HIGH
WORKS OFF THE MID ATLC COAST.
-- End Changed Discussion --

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS...

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

OVERVIEW...MODERATE CONFIDENCE IN TIMING OF CEILINGS AND CONVECTION.

THROUGH 12Z...MODERATE CONFIDENCE. EXPECT CIGS TO BE MAINLY IFR-
LIFR...THOUGH CIGS MAY RISE TO MVFR AT TIMES ACROSS THE CT VALLEY.
VSBYS ALONG THE COAST WILL ALSO REMAIN AT IFR-LIFR. MAY ALSO SEE
ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS INTO WESTERN AREAS LATE.

TODAY...MODERATE CONFIDENCE. CONTINUED UNSETTLED WEATHER. FOG AND
LOW CLOUDS WILL SLOWLY LIFT THIS MORNING. THE TAFS MAY BE TOO
FAST IN LIFTING CIGS/VSBYS...ESPECIALLY ACROSS THE COASTAL PLAIN.
SCATTERED SHOWERS/THUNDERSTORMS WILL REGENERATE DURING THE DAY
WITH MORE STRONG STORMS IN THE CT VALLEY AND CENTRAL HILLS.

THURSDAY NIGHT AND FRIDAY...LOW CONFIDENCE. VERY UNSETTLED
PATTERN WITH VARIABILITY BETWEEN VFR AND MVFR-IFR CONDITIONS IN
SHOWERS THUNDERSTORMS AND FOG. TIMING OF CONDITIONS AT SPECIFIC
TERMINALS VERY DIFFICULT TO PIN DOWN AT THIS TIME.

KBOS TERMINAL...MODERATE CONFIDENCE IN TRENDS AND CEILINGS...
MAINLY DUE TO TIMING ISSUES OF A WARM FRONT.

KBDL TERMINAL...MODERATE CONFIDENCE IN TIMING OF CONVECTION
THROUGH THE PERIOD. COULD SEE BRIEF IFR IN AN AREA OF TSRA.
POTENTIAL FOR HAIL OR WIND GUSTS TO 50 KNOTS IN ISOLATED TSTMS
THIS AFTERNOON AND EVENING.

OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...

SATURDAY...LOW CONFIDENCE. MAINLY MVFR CIGS/VSBYS WITH POCKETS OF
IFR CONDITIONS. ISOLD-SCT TSTMS POSSIBLE THROUGH EARLY AFTERNOON.
POCKETS OF IFR VSBYS IN FOG ALONG THE COAST EARLY.

SUNDAY...LOW TO MODERATE CONFIDENCE. MVFR CIGS/VSBYS POSSIBLE
THROUGH MIDDAY ACROSS S NH/N MA...OTHERWISE SHOULD SEE MAINLY VFR.
LOW CONFIDENCE ON TIMING OF EXIT OF PRECIP.

MONDAY...MODERATE CONFIDENCE. VFR.
-- 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 TODAY. A FRONT IS STALLED ACROSS THE EASTERN
WATERS THIS MORNING. THIS FRONT WILL SHIFT NORTH AS A WARM FRONT
LATER TODAY. SOUTHWEST WINDS WILL INCREASE TODAY WITH POTENTIAL
FOR 25 KT GUSTS. THIS WIND WILL CAUSE BUILDING SEAS THROUGH THE
PERIOD WITH 5-8 FOOT SEAS ON THE SOUTHERN EXPOSED WATERS AND
POSSIBLY THE EASTERN OUTER WATERS.

EXPECT LOW VSBYS IN FOG AND LOCALLY HEAVY SHOWERS. ISOLATED
THUNDERSTORMS ARE ALSO POSSIBLE.

TONIGHT-FRIDAY...MODERATE CONFIDENCE. A COLD FRONT WILL REMAIN
WEST OF THE WATERS...SO EXPECTING SOUTH TO SOUTHWEST WINDS TO
REMAIN GUSTY. LOW PROBABILITY FOR GALE-FORCE GUSTS. SEAS WELL
ABOVE 5 FT...MAINLY ACROSS THE OUTER COASTAL WATERS.

OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...

SATURDAY...LOW CONFIDENCE DUE TO TIMING OF FRONT. FRONT WILL BE
SLOW TO CLEAR THE EASTERN WATERS...BUT SHOULD DURING THE DAY. N
WINDS WILL GUST TO 25 KT MAINLY ON THE EASTERN WATERS. SEAS REMAIN
AOA 5 FT OVER THE OPEN WATERS.

SUNDAY...LOW TO MODERATE CONFIDENCE. EXPECT W-NW WIND GUSTS UP TO
25 KT AND SEAS AOA 5 FT.

MONDAY...MODERATE CONFIDENCE. WINDS AND SEAS WILL SLOWLY
DIMINISH.
-- End Changed Discussion --

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 6 AM EDT FRIDAY
     FOR ANZ232>234.
     SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 6 AM EDT
     FRIDAY FOR ANZ230-231-236-251.
     SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR ANZ235-237-250-
     254>256.
-- End Changed Discussion --

&&

$$
SYNOPSIS...BELK/EVT
NEAR TERM...BELK
SHORT TERM...BELK
LONG TERM...EVT
AVIATION...BELK/EVT
MARINE...BELK/EVT