Area Forecast Discussion
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000
FXUS61 KBOX 041057
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
657 AM EDT WED MAY 4 2016

.SYNOPSIS...

CLOUDY...DREARY AND COOL WEATHER CONTINUES THROUGH FRIDAY WITH PERIODS
OF RAIN AS WEAK WAVES OF LOW PRESSURE PASS SOUTH AND EAST OF OUR
REGION. SOME SHOWERS ARE STILL POSSIBLE AT TIMES THIS WEEKEND...BUT
TEMPERATURES WILL BEGIN TO MODERATE. SIGNIFICANT IMPROVEMENT WILL
LIKELY OCCUR EARLY TO MIDDLE OF NEXT WEEK AS HIGH PRESSURE BUILDS
IN WITH MUCH MILDER TEMPERATURES.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

*** STEADY RAIN DEVELOPS AFTERNOON-EARLY EVENING TODAY ***

7 AM UPDATE...

NO MAJOR CHANGES TO THE FORECAST OTHER THAN MINOR UPDATES TO BETTER
ALIGN WITH PRESENT TRENDS. BRIEF GLIMPSES OF SUNSHINE BEING REPORTED
THIS MORNING WHICH WILL BECOME OVERSHADOWED BY CLOUDS AND THE THREAT
OF RAIN THROUGH TODAY INTO THIS EVENING AS MID-LEVEL ENERGY AS NOTED
IN THE DISCUSSION BELOW ROTATES THROUGH THE BROADER CYCLONIC FLOW
CAPTURING AND BACK-BUILDING THE MOIST TROPICAL-ORIGIN PLUME OFFSHORE.
SUBSEQUENTLY LOOKING AT A POSSIBLE ISOLATED HEAVY DOWNPOUR /
THUNDERSTORM THREAT OVER SE NEW ENGLAND DURING THE PM COMMUTE.

PREVIOUS DISCUSSION...

WATER VAPOR IMAGERY DEPICTS A NOTABLE SHORT WAVE TROUGH OVER TN
AND KY EARLY THIS MORNING...MOVING NORTHEAST TOWARD THE MID ATLC
STATES. WELL IN ADVANCE OF THIS SYSTEM THERE IS SOME WEAK SHORT
WAVE RIDGING AND ASSOCIATED SUBSIDENCE ACROSS SOUTHERN NEW
ENGLAND. THIS WILL YIELD MOSTLY DRY CONDITIONS THIS MORNING ACROSS
THE AREA. HOWEVER BY AFTERNOON AND ESPECIALLY AFTER 5 PM THE SHORT
WAVE CURRENTLY OVER TN/KY APPROACHES THE AREA AND INDUCES A
COASTAL LOW OFF THE MID ATLC COAST. AS THE LOW TRACKS NORTHEAST THIS
WILL RESULT IN AN INCREASE IN ONSHORE ENE WINDS YIELDING ANOTHER
DAY OF COOL CONDITIONS.

AS THIS SHORT WAVE APPROACHES IT BACKS THE MID LEVEL FLOW ALONG
THE EASTERN SEABOARD AND CAPTURES A SUBTROPICAL PLUME OF MOISTURE
JUST OFFSHORE WITH PWATS OVER 1 INCH. THIS WILL RESULT IN A SHIELD
OF RAIN OVERSPREADING THE AREA BETWEEN 18Z AND 00Z. THERE IS SOME
ELEVATED INSTABILITY OVER RI AND SOUTHEAST MA THAT MAY RESULT IN A
FEW T-STORMS WITH LOCALLY HEAVY RAINFALL HERE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...

TONIGHT ...

WIDESPREAD RAIN LIKELY DURING THE EVENING BUT THEN SHOULD TRANSITION
TO SPOTTY LIGHT RAIN/DRIZZLE LATE EVENING AND OVERNIGHT AS DRY
SLOT OVERSPREADS THE AREA. HOWEVER DAMP/RAW NORTHEAST FLOW
CONTINUES AND MAINTAINS COOL TEMPS.

THURSDAY ...

FORECAST UNCERTAINTY HINGES ON LOCATION OF WARM CONVEYOR BELT
/WCB/ AND CORRESPONDING DRY SLOT. ALL NON NAM SOLUTIONS SUPPORT
DEEP LAYER MOISTURE ASSOCIATED WITH WCB REMAINING JUST OFFSHORE
AND ONLY CLIPPING EXTREME EASTERN MA. THUS GREATEST RISK FOR
APPRECIABLE RAINFALL IS OVER EASTERN MA AND SOUTHEAST MA.
ELSEWHERE ANOTHER DREARY DAY WITH MOIST AND COOL NORTHEAST WINDS
AS NEXT FRONTAL WAVE APPROACHES FROM THE SOUTH.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...

*/ HIGHLIGHTS...

 - THRU THE WEEKEND AN UNSETTLED COOL PATTERN OF LOW CLOUDS/DRIZZLE
 - TWO BOUTS OF MORE APPRECIABLE WET WEATHER: FRIDAY AND SUNDAY
 - FROST/FREEZE HEADLINES POSSIBLE MONDAY MORNING ESP OVER N/W MASS
 - MODERATE WARMING DRY TREND THRU NEXT WEEK
 - NEXT SHOT OF UNSETTLED WEATHER POSSIBLE AT THE FOLLOWING FRIDAY

*/ OVERVIEW...

COOL UNSETTLED WEATHER PATTERN CONTINUES THROUGH AT LEAST SATURDAY.
DREARY AND DRIZZLY SOCKED IN WITH LOW CLOUDS AND MIST WITH POSSIBLE
FOG RESULTING IN TEMPERATURES RUNNING BELOW-AVERAGE...ATYPICAL FOR
EARLY MAY. IN-BETWEEN TWO PERIODS OF MORE APPRECIABLE RAIN UPWARDS
OF A FEW TENTHS FORECAST. THE FIRST AROUND FRIDAY WITH THE BLOCKY
CONUS PATTERN TRAPPING A CLOSED CUT-OFF LOW AND COLD POOL AROUND THE
DELMARVA PENINSULA. DEEP LAYER FORCING THRU A CONDITIONALLY UNSTABLE
ENVIRONMENT...ANTICIPATE WIDESPREAD RAIN THOUGH CONVECTIVELY DRIVEN
MODERATE TO HEAVY SHOWERS ARE POSSIBLE. CHOKING OFF SATURDAY WITH
DRIER AIR WRAPPING IN AND A WEAK RIDGE BUILDING AHEAD OF THE N-
STREAM KICKER CONDITIONS MAY BRIEFLY IMPROVE PRIOR TO A SECOND BOUT
OF WET WEATHER SUNDAY ALONG A SWEEPING COLD FRONT.

IN WAKE OF THE COLD FRONT DREARY WEATHER IS PUSHED OUT...COOLER AIR
MOVES IN. A MODERATE RISK OF FREEZING TEMPERATURES AND FROST/FREEZE
HEADLINES FOR MONDAY MORNING ESPECIALLY OVER N/W MASS. A COOLER
AIRMASS IN PLACE BENEATH CYCLONIC FLOW AND MID LEVEL FORCING ALOFT
YIELDS CONVECTIVELY FORCED SHOWERS MONDAY. THIS ALL BEFORE A WARMING
TREND THROUGH THE FOLLOWING WEEK MORE TYPICAL FOR EARLY MAY.
ENSEMBLE MEAN H85 TEMPERATURES WARMING TO +10C SUGGEST SURFACE HIGHS
IN THE 70S BY WEDNESDAY INTO THURSDAY WHEN WINDS BEGIN TO TURN MORE
S/W. DRY FORECAST WITH HIGH PRESSURE. THE NEXT SHOT OF UNSETTLED
WEATHER IS POSSIBLE BY THE END OF THE WEEK.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...

FORECASTER CONFIDENCE LEVELS...

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

12Z UPDATE...

SHORT TERM /THROUGH THURSDAY/...MODERATE CONFIDENCE.

TODAY...

LOW-END VFR TO MVFR LOWERING DOWN TO LIFR TOWARDS THIS AFTERNOON
INTO EVENING WITH THE THREAT OF -RA. NE WINDS INCREASING 15-20 KTS
WITH GUSTS UP TO 25 KTS OVER E MASS.

TONIGHT...

WIDESPREAD IFR-LIFR. -RA THIS EVENING TAPERING OVERNIGHT. MODEST
NE WINDS 15-20 KTS WITH GUSTS UP TO 25 KTS OVER E MASS.

THURSDAY ...

GREATEST RISK FOR STEADY RAIN WILL BE OVER EXTREME EASTERN MA.
OTHERWISE NUISANCE TYPE SPOTTY LIGHT RAIN/DRIZZLE YIELDING LIFR
AND IFR TRENDING TOWARD MFR IN THE AFTERNOON.

KBOS TERMINAL...LOWERING TREND TOWARDS LATE AFTERNOON INTO
EVENING. CONFIDENT ON THE TREND BUT NOT ON THE SPECIFIC TIMING.
SCT IFR CIGS MAY FILTER IN AS EARLY AS 15Z.

KBDL TERMINAL...CIGS MAY LOWER EARLIER THEN PRESENT TAF SUGGESTS.
CONFIDENT ON THE TREND BUT NOT SO MUCH ON THE SPECIFIC TIMING.

OUTLOOK /THURSDAY NIGHT - SUNDAY NIGHT/...MODERATE CONFIDENCE.

LOW END VFR TO LIFR MIX WITH LOW CIGS AND -DZ THOUGH SUNDAY. PARENT
VSBY IMPACTS WITH BR AND POSSIBLE FOG. TWO PERIODS OF -RA FRIDAY AND
AGAIN SUNDAY. E/NE FLOW SHIFTS OUT OF THE S SUNDAY BEFORE BACKING
N/W BY SUNDAY NIGHT WITH PASSAGE OF A COLD FRONT. STRONGEST WINDS
WITH GUSTS UP TO 25 KTS WITH THE WIND SHIFT. CONDITIONS IMPROVE TO
VFR INTO MONDAY MORNING.

&&

.MARINE...

FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH THURSDAY/...HIGH CONFIDENCE.

7 AM UPDATE...NO MAJOR CHANGES TO THE FORECAST.

TONIGHT AND WEDNESDAY...PERSISTENT NE FLOW WILL BUILD SEAS TO
BETWEEN 3 AND 5 FEET ACROSS OUR SOUTHERN OUTER-WATERS. SO WHILE
WIND SPEEDS WILL GENERALLY NOT EXCEED 20 KNOTS THROUGH MIDDAY
WEDNESDAY...WILL STILL NEED SMALL CRAFT HEADLINES FOR SOME 5 FOOT
SEAS. PATCHY FOG POSSIBLE AT TIMES AS WELL.

WEDNESDAY NIGHT...PRESSURE GRADIENT INCREASES AS WAVE OF LOW
PRESSURE APPROACHES FROM THE SOUTH AND COMBINES WITH HIGH PRESSURE
OVER THE CANADIAN MARITIMES.  NORTHEAST WIND GUSTS TO 25 KNOTS MAY
DEVELOP ACROSS A GOOD CHUNK OF OUR WATERS ALONG WITH SEAS BUILDING
TO BETWEEN 4 AND 7 FEET.  ADDITIONAL SCA HEADLINES WILL LIKELY BE
NEEDED...BUT SINCE ITS 3RD PERIOD WILL WAIT UNTIL THE NEXT SHIFT
GETS A LOOK AT IT.

OUTLOOK /THURSDAY NIGHT - SUNDAY NIGHT/...MODERATE CONFIDENCE.

DREARY AND DRIZZLY CONDITIONS WITH PERSISTENT E/NE FLOW INTO SUNDAY
MORNING WITH GUSTS UP TO 25 KTS. WAVES IN EXCESS OF 5 FEET ON THE
OUTER WATERS. EXPECT RESTRICTIONS IN VISIBILITY ESPECIALLY WITH RAIN
FRIDAY. WINDS VEER S AHEAD OF A COLD FRONT WITH ADDITIONAL RAIN FOR
SUNDAY. GUSTS UPWARDS OF 25 KTS AROUND COLD FRONTAL PASSAGE AS WINDS
SHIFT OUT OF THE N/W. WAVES BUILDING 5 TO 7 FEET ON THE OUTER WATERS
THROUGH MONDAY MORNING.

&&

.TIDES/COASTAL FLOODING...

325 AM UPDATE ...

HIGH ASTRONOMICAL TIDES ARE EXPECTED...WITH PRIME CONCERN ON THE
HIGHER OF THE TWO HIGH TIDE CYCLES THURSDAY NIGHT AND FRIDAY NIGHT.

ASTRO HEIGHTS ARE PROJECTED JUST BELOW 12 FEET AT BOSTON BOTH NIGHTS.
ASTRO HEIGHTS NEAR PROVIDENCE ARE PROJECTED AT 6 FEET THURSDAY NIGHT
AND 6.5 FEET FRIDAY NIGHT. IT WILL NOT TAKE MUCH OF A SURGE ON TOP
OF THOSE ASTRO HEIGHTS TO CAUSE SOME SPLASHOVER OR EVEN POSSIBLY
SOME MINOR COASTAL FLOODING. PERSISTENT NORTHEAST WINDS AGAINST
THE EAST MASSACHUSETTS COAST WILL ADD TO POTENTIAL FOR SURGE ALONG
THAT COASTLINE. THUS THE MOST LIKELY AREA TO EXPERIENCE MINOR
COASTAL FLOODING/INUNDATION IS ACROSS EASTERN MA COASTLINE FROM
SCITUATE...HULL AND IN BOSTON/DORCESTER SUCH AS MORISSEY BLVD.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...

CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM EDT
     THURSDAY FOR ANZ230>237-250-251.
     SMALL CRAFT ADVISORY UNTIL 7 PM EDT THURSDAY FOR ANZ254>256.

&&

$$

SYNOPSIS...NOCERA/SIPPRELL
NEAR TERM...NOCERA/SIPPRELL
SHORT TERM...NOCERA
LONG TERM...SIPPRELL
AVIATION...NOCERA/SIPPRELL
MARINE...NOCERA/SIPPRELL
TIDES/COASTAL FLOODING...WFO BOX STAFF


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