-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBOX 240819
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
419 AM EDT FRI MAY 24 2013

.SYNOPSIS...
A COLD FRONT WILL MOVE SLOWLY INTO NEW ENGLAND TODAY. A LOW
PRESSURE WILL DEVELOP ON THIS FRONT...CAUSING THE ENTIRE SYSTEM
TO LINGER ACROSS THE REGION THROUGH THIS WEEKEND. THIS WILL BRING
SHOWERS AND COOLER CONDITIONS...WITH A FEW THUNDERSTORMS POSSIBLE.
SOME OF THE RAINFALL WILL BE HEAVY AT TIMES. CONDITIONS SHOULD
IMPROVE MONDAY. DRY WEATHER AND SEASONABLE TEMPS ARE EXPECTED INTO
THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
2 AM UPDATE...

FLASH FLOOD WATCH WAS EXPANDED FARTHER EAST AS RAINFALL ASSOCIATED
WITH A STRONG LOW-LEVEL JET HAS STARTED TO TRACK FARTHER WESTWARD.
THIS WOULD PUT MANY OF THE MORE URBANIZED AREAS ACROSS RI AND
EASTERN MA MORE AT RISK.

CURRENT PREFERENCE IS FOR A BLEND OF THE 24/00Z NAM AND 24/00Z
GFS FOR THE TIMING AND LOCATION OF THE VARIOUS SYNOPTIC FEATURES
TODAY INTO TONIGHT. THE GFS SOLUTION WAS SLIGHTLY FASTER TO MOVE
THE UPPER LEVEL COMPONENTS OF THIS SYSTEM AWAY FROM SOUTHERN NEW
ENGLAND THAN THE NAM. HOWEVER...THERE ARE DETAILS IN THE NAM
SOLUTION WHICH WE FELT SHOULD NOT BE IGNORED...MAINLY THE BANDING
AND INTENSITY OF THE RAINFALL WHICH ARE TOUGHER FOR THE GFS TO
RESOLVE.

EXPECTING THE COLD FRONT ACROSS EASTERN NY STATE AND NORTHEAST PA
TO SLOWLY MOVE INTO SOUTHERN NEW ENGLAND LATE TONIGHT INTO THIS
MORNING. THIS FRONT SHOULD CONTINUE TO MOVE TOWARD THE COAST
BEFORE STALLING THIS EVENING AS A LOW PRESSURE DEVELOPS ALONG IT.
THIS FRONT WILL PROVIDE PLENTY OF LIFT FOR THE ABUNDANT MOISTURE
ALREADY IN PLACE TO PRODUCE PERIODS OF MODERATE TO HEAVY RAINFALL.

CONVECTIVE INSTABILITY IS WEAK THIS MORNING...HOWEVER THE LOW-
LEVEL JET MAY BE ENOUGH OF A FOCUS TO PRODUCE A FEW THUNDERSTORMS
TODAY. THE MAIN AREA OF CONCERN FOR THAT WOULD BE RI AND EASTERN
MA.

TEMPERATURES WERE A BLEND OF THE MAV AND MET MOS GUIDANCE...WITH
SOME LOCAL BIAS-CORRECTED GUIDANCE THROWN IN FOR GOOD MEASURE.
NOT EXPECTING A LARGE DIURNAL RANGE TODAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
A DEVELOPING LOW-PRESSURE JUST EAST OF MA THIS EVENING IS NOT
EXPECTED TO MAKE MUCH PROGRESS AWAY FROM OUR REGION. HOWEVER...AS
THIS LOW DEVELOPS A DRY SLOT IS EXPECTED TO BRIEFLY CUT BACK ON
THE COVERAGE OF RAINFALL TOWARD THE EAST COAST. MAIN DEFORMATION
AND FRONTOGENESIS ZONES SHIFT INLAND AS WELL.

SEASONABLE TEMPERATURES FORECAST. A BLEND OF THE MAV/MET GUIDANCE
HANDLES THIS WELL.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...

-- Changed Discussion --
HIGHLIGHTS...

* UPPER LEVEL SYSTEM WILL KEEP SHOWERS AND COOLER TEMPS FOR THE
  WEEKEND.
* IMPROVEMENTS BEGIN ON MONDAY WITH MODERATING TEMPS THROUGH THE MID
  WEEK.
* WARM FRONT BY END OF THE WEEK WILL PUSH TEMPS WELL ABOVE AVERAGE.

CONFIDENCE LEVEL/MODEL GUIDANCE... MODERATE CONFIDENCE IN THE
OVERALL FORECAST. MODEL GUIDANCE HAS SEEM TO GET ITS ACT TOGETHER
AND HAVE A BETTER HANDLE ON THE NORTHERN STREAM SHORTWAVE AND ITS
PHASING WITH THE UPPER LEVEL TROUGH. APPEARS THAT THE 00Z GFS HAS
GOOD RUN TO RUN CONSISTENCY AND IS SUPPORTED BY SEVERAL OTHER
MODELS...INCLUDING THE 00Z EC. HAVE TRENDED THE FORECAST TO A BLEND
OF THE NAM AND GFS AND GFS/EC FOR THE EXTENDED PORTION. OVERALL HAVE
HIGH CONFIDENCE OF RAIN AND COOLER TEMPS FOR THIS WEEKEND AND DRYING
CONDITIONS FOR MONDAY. LOW CONFIDENCE ON EXACT TIMING OF PRECIP AND
THUNDER POTENTIAL. MODERATE CONFIDENCE FOR NEXT WEEK...WITH DRY
WEATHER AND SEASONABLE TEMPS FOR MID WEEK. APPEARS A WARM FRONT WILL
TRY TO LIFT JUMPING TEMPS WELL ABOVE AVERAGE...HAVE MODERATE
CONFIDENCE.

DETAILS...

THE WEEKEND...

PRECIP/QPF...
COLD AND WET HOLIDAY WEEKEND IS IN STORE FOR SOUTHERN NEW
ENGLAND. THE ONLY REGION WHICH MAY HAVE SOME HOPE IS THE
CAPE/ISLANDS AND PERHAPS EASTERN MASS...WHERE DRY AIR WILL TRY TO
PUNCH THROUGH. UPPER LEVEL TROUGH WILL PUSH OVER THE REGION AND
PINWHEEL OVER SOUTHERN NEW ENGLAND TIL SUNDAY BEFORE PUSHING
NORTHWARD. SURFACE LOW OVER CAPE COD CANAL WILL PUSH EASTWARD OF
THE NORTH SHORE. THIS MAY ALLOW FOR SLIGHTLY WARMER TEMPS AND
DRIER CONDITIONS FOR THE CAPE ON SATURDAY AS DRY AIR INTRUSION
WILL PUSH THROUGH AS LOW PRESSURE UNDERGOES CYCLOGENESIS. APPEARS
THAT A GOOD WRAP AROUND OF RAIN ON THE BACK SIDE OF THE LOW WILL
DEVELOP OVER THE CT VALLEY AND DROP OVER AN INCH TO PERHAPS 2
INCHES OF PRECIP FOR THE WEEKEND IN THIS REGION...MAY NEED TO
WATCH FOR POSSIBLE RIVER FLOODING AS THERE HAVE BEEN SEVERAL
INCHES ALREADY FALLEN OVER THE PAST 24 HRS...WITH MORE ON THE
WAY. SURFACE LOW WILL GET PUSHED MORE NORTHWARD INTO THE GULF OF
MAINE...THIS WILL PUSH PRECIP FARTHER EAST AND NORTHWARD ON
SUNDAY AND SLOWLY DISSIPATE FROM SOUTH TO NORTH SUNDAY NIGHT. MAY
BE A TAD SLOW ON TIMING OF PRECIP YET HAVE LOW CONFIDENCE ON THE
EXACT EXIT TIMING.

THUNDER...
THERE IS A LOW PROBABILITY OF THUNDER FOR SATURDAY AND INTO SUNDAY.
HOWEVER INCLUDED AN ISOLATED CHANCE AS TOTAL TOTALS REACH ABOVE 50
AND SURFACE LIS DO DROP TO NEAR 0. APPEARS THAT THE POTENTIAL IS
THERE ESP ACROSS THE EASTERN HALF OF THE REGION ON SATURDAY THANKS
TO THE DRY AIR ALLOWING FOR SOME DIURNAL HEATING TO BREAK THROUGH.
DO NOT ANTICIPATE ANYTHING TO BE STRONG OR SEVERE. HOWEVER WITH IT
BEING A HOLIDAY WEEKEND WANTED TO FOCUS ON THAT THE POTENTIAL IS
THERE.

TEMPERATURES...
AS UPPER LEVEL LOW DROPS OVER SOUTHERN NEW ENGLAND...A COLD POOL
WILL SET UP ALLOWING FOR TEMPS TO DROP WELL BELOW AVERAGE. EXPECT
HIGHS TO STRUGGLE TO REACH INTO THE 60S ON SATURDAY AND THE MID
60S ON SUNDAY. LOWS OVERNIGHT DO GET QUITE CHILLY...IN THE MID TO
UPPER 30S.


MONDAY AND WEDNESDAY...

MONDAY IS A TRANSITION DAY FROM THE SOGGY COOL WEEKEND TO A
WARM...DRY MID-WEEK. UPPER LEVEL LOW WILL CONTINUE TO PUSH OFF SHORE
INTO THE GULF OF MAINE...ALLOWING FOR MIDWEST RIDGE TO BUILD.
SURFACE HIGH PRESSURE WILL SLIDE OVER AND HELP KEEP A DRY FORECAST
FOR MOST OF THE WORK WEEK. HOWEVER CANNOT RULE OUT A SPOT SHOWER OR
TWO...ESP IF SEA BREEZES DEVELOPS. TEMPS WILL INCREASE THROUGH THE
MID-WEEK...WITH UPPER 60S FOR MONDAY TO UPPER 70S BY WEDNESDAY.

THURSDAY...
MOTHER NATURE IS TRYING TO MAKE UP FOR THE COLD/RAINY WEEKEND BY
BRING A STRONG WARM FRONT TO SOUTHERN NEW ENGLAND BY LATE WEEK.
THIS WARM FRONT WILL BRING MUGGY CONDITIONS AND A CHANCE OS
ISOLATED SHOWERS. HOWEVER MAIN THINK TO WATCH IS MAX TEMPS...WHICH
MAY REACH THE MID 80S. SOME MODELS EVEN PUSH THE REGION INTO THE
90S. SINCE THIS IS SEVERAL DAYS AWAY...KEEP IN MIND THAT MOTHER
NATURE MAY CHANGE HER MIND.
-- End Changed Discussion --

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS...

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

OVERVIEW...MODERATE CONFIDENCE.

THROUGH 12Z...MVFR-IFR CONDITIONS EXPECTED IN MODERATE TO HEAVY
RAINFALL...ESPECIALLY TOWARD THE EAST COAST. LLWS POSSIBLE TOWARD
THE OUTER CAPE AND ADJACENT COASTAL WATERS AS A STRONG SOUTHERLY LOW-
LEVEL JET NUDGES ITS WAY NORTH.

TODAY...MVFR-IFR CIGS/VSBYS CONTINUE THROUGH THE DAY. WINDS SHIFT
TO W-NW ACROSS WESTERN AREAS THIS AFTERNOON...THEN LATE TODAY
ACROSS THE EASTERN AREAS. LOCALLY HEAVY RAINFALL...MAINLY THIS
MORNING. LLWS LIKELY ACROSS CAPE/ISLANDS THROUGH MIDDAY.

TONIGHT...EXPECTING SOME IMPROVEMENT TO VSBYS OVERNIGHT...
PARTICULARLY INLAND. NOT MUCH IMPROVEMENT IN CIGS THOUGH.

KBOS TERMINAL...MODERATE CONFIDENCE...MAINLY DUE TO TIMING ISSUES.
SCATTERED TSRA POSSIBLE. LLWS LIKELY EAST OF THE TERMINAL FOR
APPROACHES OVER THE OCEAN.

KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE IN
TIMING.

OUTLOOK...SATURDAY THROUGH TUESDAY...

THE WEEKEND...LOW TO MODERATE CONFIDENCE. VERY UNSETTLED PATTERN
WITH VARIABILITY BETWEEN VFR CONDITIONS AND MVFR/IFR CONDITIONS IN
SHRA/TSRA/FOG. IMPROVING CONDITIONS LATE SUNDAY NIGHT INTO MONDAY
MORNING FROM SOUTH TO NORTH.

MONDAY INTO TUESDAY...HIGH CONFIDENCE. VFR. LOW CONFIDENCE ON SEA
BREEZE DEVELOPMENT.
-- 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 LOW-LEVEL JET AND MODERATE TO HEAVY RAINFALL WILL BRING NEAR 25
KT GUSTS ON THE WATERS EARLY THIS MORNING. A STRONG LOW-LEVEL
INVERSION WILL LIMIT GUSTS...SO GALES NOT EXPECTED. PERSISTENT SW
FLOW WILL RESULT IN BUILDING SEAS TODAY. WINDS WILL DIMINISH LATER
TODAY AS THIS LOW-LEVEL JET DEPARTS. EXPECTING LOW VSBYS IN FOG
AND LOCALLY HEAVY SHOWERS. ISOLATED THUNDERSTORMS ARE ALSO
POSSIBLE.

TONIGHT...MODERATE CONFIDENCE. A LOW PRES AND COLD FRONT WILL
LIKELY STALL ACROSS THE EASTERN NEAR-SHORE WATERS. WIND DIRECTIONS
WILL BE QUITE DIFFERENT DEPENDING UPON WHERE THIS FRONT SETS UP
EXACTLY. SOUTH WINDS SHOULD CONTINUE TO DIMINISH...BEFORE
REINTENSIFYING FROM THE NORTH BEHIND THIS LOW PRESSURE. LOW
PROBABILITY FOR THUNDERSTORMS. AREAS OF LOW VSBYS IN HEAVIER
SHOWERS AND PATCHY FOG. SEAS WILL REMAIN 5 FT OR HIGHER...MAINLY
ACROSS THE OPEN WATERS.

OUTLOOK...SATURDAY THROUGH TUESDAY...

THE WEEKEND...UPPER LEVEL SYSTEM WILL LINGER ACROSS NEW ENGLAND AS
SURFACE LOW STAYS OVER THE NEW ENGLAND WATERS. EXPECT SEAS TO REMAIN
HIGH FOR MOST OF THE WEEKEND. SMALL CHANCE FOR AN ISOLATED T-
STORMS...BUT RAIN/SHOWERS WILL LOWER VSBYS ESP ON SATURDAY. GUSTY NW
BRING GUSTS CLOSE TO GALE FORCE SAT INTO SAT NIGHT...HAVE HOISTED A
GALE WATCH. STRONG SCA WILL BE NEEDED FOR SUNDAY.

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

&&

.HYDROLOGY...
EXPANDED FLASH FLOOD WATCH TO RI AND SE MA...AS FAR N AS
BOS...BASED ON RADAR AND SATELLITE TRENDS. LATEST NAM...RAP AND
HRR MODELS ALSO DEPICT THIS AREA. THE LOW LEVEL JET IS FORECAST TO
SHIFT E DURING THE MORNING HOURS BUT WV IMAGERY DEPICTS A LITTLE
SHARPENING OF THE MID TROPOSPHERIC TROUGH AS IT HEADS TOWARD THE
EASTERN SEABOARD. IR AND WV IMAGERY SHOWS FAIRLY IMPRESSIVE
TROPICAL CONNECTION ATTM. WE WILL EVENTUALLY LOSE THAT BUT
PROBABLY NOT UNTIL LATER IN THE DAY.

TWO AREAS ARE BEING WATCHED ESPECIALLY CLOSELY FOR NEED FOR FLASH
FLOOD WARNINGS. ONE IS THE URBAN AREAS OF SE MA...INCLUDING FALL
RIVER AND NEW BEDFORD. THERE DOES SEEM TO BE SOME EASTWARD SHIFT
OF THE HEAVY RAIN AXIS...CONSISTENT WITH THE LOW LEVEL JET
FORECAST ON THE NAM AND GFS. BOTH LOCATIONS CAN FLOOD QUICKLY
HOWEVER SO WATCHING VERY CLOSELY. SECOND AREA IS NORTHERN
WORCESTER COUNTY AND FAR NW MIDDLESEX COUNTY WHERE PERSISTENT BAND
IS CAUSING SHARP RISES IN SMALL STREAMS. THE NORTH NASHUA RIVER AT
FITCHBURG ITSELF IS SHOWING A MODERATELY STEEP RISE AND NEEDS TO
BE WATCHED CLOSELY. SATELLITE IMAGERY IS SHOWING COOLING TOPS
HEADING TOWARD NORTHERN WORCESTER COUNTY AND SO A FLASH FLOOD
WARNING MAY BECOME NECESSARY IN THE NEAR FUTURE THERE.

&&

.TIDES/COASTAL FLOODING...

-- Changed Discussion --
EAST COAST OF MA THIS WEEKEND...
ASTRONOMICAL HIGH TIDES WILL OCCUR THIS WEEKEND INTO EARLY NEXT
WEEK. WITH A SURFACE LOW LINGERING JUST OFF THE SOUTHERN NEW
ENGLAND EAST COAST SATURDAY INTO SUNDAY...EXPECTING GUSTY
NORTHERLY TO NORTHWEST WINDS ESPECIALLY DURING THE DAYTIMES HOURS.
AT BOSTON...A HIGH TIDE OF 11.9FT WILL OCCUR TONIGHT AT 11:21 PM
AND 12.2 FT EARLY SUNDAY MORNING AT 12:12 AM. EXPECTING LIGHT
SOUTHERLY WINDS DURING TODAY/S DAYTIME HIGH TIDE...SO THIS IS LESS
OF A CONCERN. LOOKING AT THE SUNDAY MORNING HIGH TIDE... NORTHERLY
TO NORTHWESTERLY WINDS MAY HELP INCREASE THE SURGE ESPECIALLY FOR
CAPE COD BAY. RIGHT NOW ONLY EXPECTING MINOR SPLASHOVER ACROSS
NORTH-FACING BEACHES. WILL NEED TO CONTINUE TO MONITOR AND UPDATE
WITH THE LATEST FORECAST GUIDANCE.
-- End Changed Discussion --

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...FLASH FLOOD WATCH UNTIL NOON EDT TODAY FOR CTZ002>004.
MA...FLASH FLOOD WATCH UNTIL NOON EDT TODAY FOR MAZ002>004-008>013-
     015>021-026.
NH...FLASH FLOOD WATCH UNTIL NOON EDT TODAY FOR NHZ011-015.
RI...FLASH FLOOD WATCH UNTIL NOON EDT TODAY FOR RIZ001>007.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR
     ANZ231>234-251.
     GALE WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY MORNING FOR
     ANZ235-237-255-256.
     SMALL CRAFT ADVISORY UNTIL 2 PM EDT SATURDAY FOR ANZ235-237-
     255-256.
     SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ250-254.
-- End Changed Discussion --

&&

$$
SYNOPSIS...BELK/DUNTEN
NEAR TERM...BELK
SHORT TERM...BELK
LONG TERM...DUNTEN
AVIATION...BELK/DUNTEN
MARINE...BELK/DUNTEN
HYDROLOGY...THOMPSON
TIDES/COASTAL FLOODING...DUNTEN