Area Forecast Discussion
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000
FXUS61 KBOX 050800
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
400 AM EDT THU MAY 5 2016

.SYNOPSIS...
CLOUDY...DREARY AND COOL WEATHER CONTINUES THROUGH FRIDAY WITH
PERIODS OF RAIN AS WAVES OF LOW PRESSURE TRACK NEAR SOUTHERN NEW
ENGLAND. DESPITE SOME SHOWERS POSSIBLE THIS WEEKEND THERE WILL BE
MANY HOURS OF DRY WEATHER ALONG WITH MODERATING TEMPERATURES.
SIGNIFICANT IMPROVEMENT WILL LIKELY OCCUR EARLY TO MIDDLE OF NEXT
WEEK AS HIGH PRESSURE BUILDS IN WITH MUCH MILDER TEMPERATURES.

&&

.NEAR TERM /UNTIL 11 PM THIS EVENING/...

*** MORE RAIN POSSIBLE LATE TODAY AND THIS EVENING BUT LIKELY
CONFINED TO CAPE COD AND THE ISLANDS ***

THIS MORNING ...

DRY SLOT HAS OVERSPREAD THE REGION EARLY THIS MORNING BRINGING AN
END TO THE STEADY RAINS FROM LAST EVENING. HOWEVER AT THE SURFACE AN
INVERTED TROUGH OFFSHORE COUPLED WITH 1020 MB HIGH OVER THE
MARITIMES IS GENERATING A STIFF AND MOIST NE LOW LEVEL JET INTO THE
REGION. THIS IS RESULTING IN OVERCAST CONDITIONS ALONG WITH SPOTTY
LIGHT RAIN/DRIZZLE. IN ADDITION...WITH OCEAN TEMPS ONLY IN THE M40S
THIS NE WIND TRAJECTORY WILL LIMIT HIGHS TODAY TO THE 40S...POSSIBLY
L50S ACROSS CT RVR VLY. IT WILL FEEL EVEN COOLER GIVEN THE NE WINDS
ESPECIALLY ALONG THE EASTERN MA COASTLINE. KEEP IN MIND THE NORMAL
DAYTIME HIGH FOR EARLY MAY IS IN THE 60S.

THIS AFTERNOON AND EVENING ...

WATER VAPOR IMAGERY SHOWS A VIGOROUS SUBTROPICAL JET ACROSS THE GULF
OF MEXICO AND ACROSS FL WITH THE NOSE OF A 110KT JET STREAK OFF THE
COAST OF GA/SC. THIS JET IMPULSE INITIATES CYCLOGENESIS EARLY THIS
MORNING OFF THE CAROLINAS. NEW 00Z EC/UKMET/RGEM/ARW AND NMM HAVE
ALL TRENDED WEAKER/FLATTER AND FARTHER OFFSHORE WITH THIS DEVELOPING
SYSTEM AS IT TRACKS EAST OF 40N/70W BENCHMARK. THUS HAVE FOLLOWED A
NON-NAM SOLUTION HERE. THIS SCENARIO FOCUSES STEADY RAIN /PERHAPS
MODERATE TO HEAVY FOR AT TIME/ TO CAPE COD AND THE ISLANDS LATE
TODAY AND EVENING. FARTHER WEST THE RISK OF A STEADY/HEAVIER RAIN
DIMINISHES RAPIDLY. THEREFORE IT/S POSSIBLE MUCH OF THE DAY ACROSS
RI/CT AND WESTERN-CENTRAL JUST DEALS WITH SPOTTY LIGHT RAIN/DRIZZLE
THIS MORNING WITH A DRYING TREND THEREAFTER. NEVERTHELESS WILL HAVE
TO WATCH THIS CAREFULLY AS A SHIFT OF 50-100 MILES WEST WOULD RESULT
IN STEADY AND HEAVIER RAIN TRACKING NEAR RI AND THE WORCESTER HILLS.

IT WILL BECOME BREEZY TO WINDY ACROSS EASTERN MA AS 925 MB LOW LEVEL
NE JET INCREASES TO 35 TO 45 KT.

&&

.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM FRIDAY/...

TONIGHT ... RAIN SHIELD ASSOCIATED WITH COASTAL LOW WILL PULL AWAY
FROM CAPE COD AND THE ISLANDS AS DRY SLOT APPROACHES FROM THE SOUTH.
THIS MAY RESULT IN AREAS OF DRIZZLE AND FOG FORMING WITH DRY AIR
ALOFT AND MOIST NE LOW LEVEL FLOW ACROSS SOUTHERN NEW ENGLAND.

FRIDAY ... OTHER THAN SPOTTY LIGHT RAIN/DRIZZLE THE DAY SHOULD START
OFF MAINLY DRY. IN FACT SOME OF THE MODEL GUID SUGGEST THERE COULD
BE A FEW BREAKS OF SUNSHINE ACROSS CAPE COD AND NANTUCKET EARLY IN
THE MORNING. ALTHOUGH THIS WILL BE SHORT LIVED AS VERTICALLY
STACKED LOW TRACKS FROM THE MID ATLC TO THE NJ COAST. THIS ADVECTS
DEEP LAYER MOISTURE IN THE FORM OF RAIN INTO CT AND WESTERN-CENTRAL
MA FRI AFTN. PRECIP MAY NOT REACH EASTERN MA UNTIL AFTER DARK.

IT WILL BECOME BREEZY ONCE AGAIN ACROSS EASTERN MA AS EAST WINDS
INCREASE.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...

*/ HIGHLIGHTS...

 - DREARY WEATHER OF LIGHT RAIN / DRIZZLE FRIDAY NIGHT - SATURDAY
 - COLD FRONT AND BEST CHANCES OF RAIN ON SUNDAY
 - QUICK BLAST OF COLDER AIR MONDAY MORNING BEHIND THE FRONT...DRY
 - POSSIBLE PROLONGED PERIOD OF UNSETTLED WEATHER THRU THE WEEK

*/ DISCUSSION...

TACKLING AN ENSEMBLE FORECAST APPROACH WITH A BROADER VIEW...BLOCKY
FLOW PATTERN DEAMPLIFIES WHILE SEEMINGLY TO SUBTLY SHIFT E OVER THE
COURSE OF NEXT WEEK. RIDGING PREVAILS ACROSS THE NE PACIFIC INTO THE
GULF OF ALASKA WITH TROUGHING OVER THE N-CENTRAL CONUS. DOWNSTREAM
RIDGING IS PREFERRED OVER THE NE CONUS WITH A FAVORABLE ENVIRONMENT
FOR STORM DEVELOPMENT S OF GREENLAND. PERHAPS A CONSEQUENCE OF POOR
FORECAST CONSENSUS OF THE PACIFIC NORTH AMERICA PATTERN...WHAT WAS
JUST A DAY OR TWO AGO A FORECAST OF DRY WEATHER AND TEMPERATURES
INTO THE 70S HAS BEEN COMPLETELY OBLITERATED INTO RENEWED PERIOD
OF DREARY WET WEATHER.

SO AN INITIAL WET AND DREARY PERIOD BENEATH A DYING LOW OCCLUSION
FRIDAY NIGHT INTO SATURDAY. SHOWERS ERODING INTO POCKETS OF LIGHT
RAIN / DRIZZLE AS DRIER AIR WRAPS INTO THE SYSTEM. TRICKY FORECAST
THAT WARRANTS AT LEAST CHANCE POPS. OVERALL SATURDAY INTO SATURDAY
NIGHT DOES NOT APPEAR TO BE A WASH-OUT...PERHAPS THE SALVAGEABLE DAY
OF THE WEEKEND PRIOR TO THE DISMAL WEATHER CONCLUDING SUNDAY AS A
N-STREAM DISTURBANCE AND ATTENDANT COLD FRONT SWEEPS NEW ENGLAND
WITH THE BEST AND LIKELY CHANCES OF RAIN. BEHIND THIS FRONT WILL
SEE A QUICK BLAST OF COLD AIR ADVECTION AND BREEZY W/NW FLOW.
OVERALL TEMPERATURES THROUGHOUT THE AFOREMENTIONED FORECAST PERIOD
REMAINING BELOW-AVERAGE.

THEREAFTER A LOW CONFIDENCE FORECAST. FROM AN ENSEMBLE APPROACH IT
WOULD APPEAR ENERGY OUT OF THE N-CENTRAL CONUS DEAMPLIFIES BENEATH A
MID-UPPER LEVEL CONFLUENT FLOW PATTERN AND FAVORABLE RIDGING. BUT IN
EVALUATING DETERMINISTIC GUIDANCE...VARIANCE IS EVIDENT IN HANDLING
INDIVIDUAL WAVES THROUGH THE MID LEVEL FLOW WITH THE 05.0Z ECMWF
HIGHLIGHTING A MORE ROBUST N STREAM WAVE AROUND MIDWEEK. LEANING ON
AN ENSEMBLE-WEIGHTED FORECAST WILL LEAN TOWARDS A FORECAST OF WAVE
ENERGY SWEEPING ALONG A STALLED W TO E FRONTAL BOUNDARY BETWEEN THE
C-CONUS AND STORMS DEVELOPING S OF GREENLAND. NO CERTAINTY ON THE
EXACT FRONTAL BOUNDARY / BAROCLINIC ZONE BUT A PROLONGED PERIOD
LOOKS PLAUSIBLE OF NUISANCE LIGHT TO MODERATE RAIN UNDER BROKEN TO
OVERCAST CONDITIONS WHICH WILL MAKE CONDITIONS COOLER THAN AVERAGE
TOWARDS MID MAY. CAN NOT RULE OUT SOME BREAKS IN-BETWEEN AND SUN-
SHINE...AND IF THE BOUNDARY LAYER IS ABLE TO MIX OUT AND H85
TEMPERATURES HOVER AROUND +10C WE COULD SEE SEASONABLE TEMPERATURES
AROUND THE 60S. AGAIN...A LOW CONFIDENCE FORECAST FROM TUESDAY INTO
THE FOLLOWING WEEKEND.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...

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

4 AM UPDATE ...

SHORT TERM /THROUGH FRIDAY/ ... HIGH CONFIDENCE ON TRENDS BUT
LOWER ON EXACT DETAILS.

THRU 12Z ... PERSISTENCE A GOOD SHORT TERM FORECAST IN THIS
REGIME. THUS EXPECT MVFR ACROSS CT RVR VLY WITH IFR ELSEWHERE.
MAINLY DRY BUT AREAS OF DRIZZLE POSSIBLE. GUSTY NE WINDS UP TO 25
KT WITH STRONGEST WINDS ALONG THE IMMEDIATE COAST.

AFTER 12Z ... MVFR ACROSS CT RVR VLY SPREADS EASTWARD INTO RI AND
CENTRAL MA HOWEVER IFR LIKELY LINGERS ACROSS EASTERN MA. NE WINDS
INCREASE TO 30-35 KT LATE IN THE DAY OVER EASTERN MA. RAIN
REDEVELOPS ACROSS EASTERN MA AROUND 21Z AND THEREAFTER.

TONIGHT ... MVFR EXCEPT IFR EASTERN MA IN STEADY RAIN BUT THEN A
DRYING TREND AFTER MIDNIGHT ALONG WITH IFR CONFINED TO ONLY
SOUTHEAST MA. GUSTY NE WINDS 30-35 KT ACROSS EASTERN MA SLOWLY
EASE LATE.

FRI ... MVFR LIKELY WITH RAIN REDEVELOPING LATE IN THE DAY ACROSS
CT. NE WINDS FAIRLY LIGHT EARLY BUT THEN BEGINNING TO INCREASE
LATE IN THE DAY.

KBOS TERMINAL ... UNCERTAINTY IN TAF CENTERED ON POTENTIAL
STEADY/HEAVY RAIN 21Z TODAY THRU 03Z THIS EVENING. HEAVIEST RAIN
MAY REMAIN OFFSHORE. OTHERWISE ANY RAIN TODAY WILL BE LIGHT AND
SPOTTY.

KBDL TERMINAL ... HIGH CONFIDENCE IN TAF.

OUTLOOK /FRIDAY NIGHT - MONDAY NIGHT/...MODERATE CONFIDENCE.

LOW END VFR TO LIFR MIX WITH LOW CIGS AND VSBY RESTRICTIONS PER
SHRA/DZ/BR INITIALLY...IMPROVING THROUGH SATURDAY. E WINDS VEER S
WHILE INCREASING AHEAD OF A COLD FRONT SWEEPING TERMINALS SUNDAY
WITH GUSTS UP TO 25 KTS. POSSIBLE LLWS AND LIKELY -RA/RA IMPACTS
PRIOR TO THE COLD FRONT...BEHIND WHICH WINDS BACK W/NW AND ARE
IMMEDIATELY GUSTY WITH UP TO 30 KTS SUNDAY NIGHT INTO MONDAY
MORNING. IMPROVING VFR WHILE WINDS W/NW WINDS DIMINISH MONDAY INTO
MONDAY NIGHT.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

4 AM UPDATE ...

TODAY ... NE WINDS INCREASE TO 30-35 KT LATER THIS MORNING INTO THIS
AFTERNOON. THUS GALES HAVE BEEN POSTED. PATCHY DRIZZLE AND FOG MAY
REDUCE VSBY.

TONIGHT ... NE GALES CONTINUE DURING THE EVENING FOLLOWED BY WINDS
DIMINISHING AFTER MIDNIGHT. VSBY MAY BE REDUCED IN AREAS OF FOG AND
DRIZZLE AT TIMES.

FRI ... LOW PRES MOVES UP THE COAST FROM THE MID ATLC TO NJ. THIS
WILL RESULT IN EAST WINDS INCREASING AS THE DAY PROGRESSES ALONG
WITH RAIN OVERSPREADING THE RI WATERS IN THE AFTERNOON.

OUTLOOK /FRIDAY NIGHT - MONDAY NIGHT/...MODERATE CONFIDENCE.

WET WEATHER CONTINUES FRIDAY NIGHT UNDER E/NE FLOW WITH POTENTIAL
VISIBILITY RESTRICTIONS. CONDITIONS IMPROVE SATURDAY INTO SATURDAY
NIGHT AS E WINDS VEER S ALLOWING WAVE ACTION TO DIMINISH. BUT SHORT
LIVED AS S WINDS INCREASE AHEAD OF A COLD FRONT SWEEPING THE WATERS
LATE SUNDAY. GUSTS TO 25 KTS AHEAD OF THE FRONT WITH WAVES BUILDING
5 TO 7 FEET...BACKING W/NW WITH GUSTS TO 30 KTS IMMEDIATELY BEHIND
THE FRONT DIMINISHING MONDAY INTO MONDAY NIGHT ALLOWING WAVES TO
DIMINISH BELOW 5 FEET BY THE END OF PERIOD.

&&

.TIDES/COASTAL FLOODING...

COASTAL FLOOD ADVISORY HAS BEEN POSTED FOR THIS EVENING/S HIGH TIDE.
ASTRO TIDE AT BOSTON IS 11.95 FT AT 10:55 PM. NE WINDS OF 25 TO 35
KT THIS AFTERNOON AND EVENING WILL RESULT IN A STORM SURGE AROUND 1
FT. THIS COMBINED WITH SOME WAVE ACTION ONTOP OF THE SURGE WILL BE
SUFFICIENT TO PRODUCE MINOR COASTAL FLOODING ALONG THE EASTERN MA
COASTLINE FROM BOSTON SOUTHWARD THRU PLYMOUTH COUNTY...CAPE COD BAY
AND NANTUCKET. RISK IS LOWER NORTH OF BOSTON BUT LATER SHIFTS WILL
HAVE TO EVALUATE FOR POTENTIAL HEADLINES.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...COASTAL FLOOD ADVISORY FROM 9 PM THIS EVENING TO 1 AM EDT
     FRIDAY FOR MAZ015-016-019-022-024.
RI...NONE.
MARINE...GALE WARNING FROM NOON TODAY TO 2 AM EDT FRIDAY FOR ANZ231>235-
     237.
     GALE WARNING FROM NOON TODAY TO 10 PM EDT THIS EVENING FOR
     ANZ230-236.
     GALE WARNING FROM NOON TODAY TO 2 AM EDT SATURDAY FOR ANZ250-
     251-254>256.

&&

$$
SYNOPSIS...NOCERA/SIPPRELL
NEAR TERM...NOCERA
SHORT TERM...NOCERA
LONG TERM...SIPPRELL
AVIATION...NOCERA/SIPPRELL
MARINE...NOCERA/SIPPRELL
TIDES/COASTAL FLOODING...NOCERA


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