Area Forecast Discussion
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FXUS61 KBOX 060221
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1021 PM EDT THU MAY 5 2016

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

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...

10 PM UPDATE ...

COASTAL LOW OVER GEORGES BANK AND ITS RAIN SHIELD OVER EASTERN MA CONTINUES
TO MOVE NORTHEAST AND PULL AWAY FROM THE REGION. THUS A DOWNWARD
TREND IN RAINFALL IS EXPECTED OVERNIGHT. HOWEVER NOTING LOWER TOP
RAIN OCCURRING OVER THE WORCESTER HILLS/NORTHERN RI AND HILLY
TERRAIN OF NORTHEAST CT. THIS IS PARTIALLY ATTRIBUTED TO UPSLOPE
FLOW FROM NORTHEAST WINDS.

ALSO NOTEWORTHY IS WATER VAPOR IMAGERY BEGINNING TO SHOW DEEPER
WARM CONVEYOR BELT MOISTURE FROM CLOSED LOW OVER THE MID ATLC IS
BEGINNING TO STREAM NORTHWARD OFF THE OCEAN ACROSS LONG ISLAND AND
CT. THIS WILL RESULT IN RAIN CHANCES INCREASING ACROSS CT INTO
WESTERN MA AS THE NIGHT PROGRESSES.

POPS WERE ADJUSTED TO THE ABOVE THINKING.

OTHER CHANGE TO THE FORECAST WAS TO INCREASE WINDS AS OBSERVATIONS
INDICATE WINDS UP TO 35 KT AT EWB/36 KT AT MVY/38 KT AT FMH AND 39
KT AT ACK! THESE WINDS ARE PROVIDING WIND CHILLS IN THE 30S!

PREVIOUS DISCUSSION...

LOW PRESSURE SEVERAL HUNDRED MILES SOUTH OF NANTUCKET WAS
PROGRESSING TO THE NORTHEAST EARLY THIS EVENING. IT IS FORECAST TO
REACH THE BAY OF FUNDI BY DAYBREAK. RAIN...LOCALLY MODERATE TO
HEAVY...WAS OCCURRING OVER SOUTHEAST MA. THE WESTERN EDGE OF THIS
RAIN SHIELD IS EXPECTED TO PROGRESS SLIGHTLY FARTHER TO THE WEST
EARLY TONIGHT...REACHING THE I-495 CORRIDOR AND TO NEAR THE RI/CT
BORDER. THEN IT SHOULD HEAD OFF THE COAST AROUND OR AFTER
MIDNIGHT. WITH THE MOIST NORTHEAST FLOW...AREAS OF DRIZZLE AND FOG
CAN ALSO BE EXPECTED ANYWHERE IN SOUTHERN NEW ENGLAND OVERNIGHT...
BUT MOST LIKELY IN CENTRAL AND EASTERN SECTIONS.

MESOSCALE MODELS SHOW THE LOW LEVEL JET INCREASING FOR A FEW HOURS
BETWEEN NOW AND ABOUT 10 PM...SO NORTHEAST GUSTS TO 25-35 MPH WILL
CONTINUE THIS EVENING IN RI AND EASTERN MA. WINDS WILL DIMINISH
ACROSS THE REGION AFTER MIDNIGHT.

THERE IS THE LIKELIHOOD OF MINOR COASTAL FLOODING AT THE TIME OF
HIGH TIDE TONIGHT. PLEASE REFER TO THE COASTAL FLOODING SECTION
BELOW FOR MORE INFORMATION.

LOWS TONIGHT WILL BE IN THE 40S.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
FRIDAY...
A SECOND LOW PRESSURE SYSTEM WILL DEVELOP OFF OF DELMARVA BY
DAYBREAK FRI AND WORK ITS WAY WESTWARD INTO NEW JERSEY DURING THE
DAY. THIS KEEPS OUR REGION IN MOIST FLOW OFF THE OCEAN...BUT MORE
OF AN EAST TO SOUTHEAST DIRECTION INSTEAD OF NORTHEAST. THIS WILL
ALLOW TEMPERATURES TO MODERATE WITH HIGHS REACHING 55 TO 60 EXCEPT
COOLER ON THE CAPE AND ISLANDS AND IMMEDIATE COAST OF CAPE ANN. IT
WILL BECOME BREEZY ONCE AGAIN ACROSS EASTERN AND SOUTHERN PORTIONS
OF THE AREA.

WHILE IT COULD SHOWER AT ANY TIME...THE GREATEST CHANCE OF
SHOWERS WILL BE OVER CT AND WESTERN MA FROM MID AFTERNOON INTO
FRI EVENING. PROBABILITIES INCREASE TO LIKELY WEST OF THE CONNECTICUT
RIVER IN BOTH MA AND CT BY LATE AFTERNOON. QPF AMOUNTS RANGE FROM
LESS THAN A TENTH OF AN INCH ON THE GFS TO 0.3 TO 0.4 INCHES ON
THE ECMWF AND NAM.

FRIDAY NIGHT...
A COLD POOL ALOFT WITH 500 MB TEMPERATURES OF -22C MOVES INTO
WESTERN PORTIONS OF CT AND MA FRI EVENING. THIS CAUSES A FAIR
AMOUNT OF INSTABILITY WITH TOTAL TOTALS INDICES REACHING
50-55...THE SHOWALTER INDEX BETWEEN 0 AND -2...AND EVEN THE LIFTED
INDEX FROM 0 TO -1 IN THOSE AREAS. WILL CONTINUE WITH A CHANCE OF
SHOWERS AND CANNOT EVEN RULE OUT AN ISOLATED THUNDERSTORM
ANYWHERE ACROSS THE FORECAST AREA FRI NIGHT. LOWS WILL BE IN THE
MID AND UPPER 40S.

WE CANNOT RULE OUT POCKETS OF MINOR COASTAL FLOODING FRI NIGHT
AGAIN...BUT THE THREAT IS LESS THAN TONIGHT. PLEASE SEE COASTAL
FLOOD SECTION BELOW.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
*/ HIGHLIGHTS...

 - DREARY WEATHER OF LIGHT RAIN / DRIZZLE 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

OVERVIEW AND MODEL PREFERENCES...
FINAL BREAKDOWN OF THE AMPLIFIED FLOW PATTERN ACROSS THE CONUS
BEGINS LATE SAT INTO SUN AS ARCTIC VORT MAX WITHIN THE NRN STREAM
IS FINALLY ABLE TO SHIFT THE STUBBORN CUTOFF E OF THE REGION. THIS
WILL COME WITH SOME CONSEQUENCE IN THE FORM OF A COLD FRONTAL
PASSAGE ON SUN...BUT AT THE VERY LEAST...SOME MODERATION IN TYPES
AND DRYING OF THE COLUMN IS EXPECTED.

BEYOND THE WEEKEND...CONFIDENCE IN THE FORECAST WAINS. AT ISSUE
IS THE DEVELOPMENT OF YET ANOTHER CUTOFF DEVELOPS TO THE N AS THE
NRN STREAM VORT MAX PHASES WITH SRN STREAM ENERGY EARLY IN THE
WEEK. THE RESULTING CUTOFF COULD END UP ANYWHERE FROM ONTARIO TO S
OF GREENLAND...AND THIS LOCATION WILL ULTIMATELY HELP TO DEFINE
THE DAILY SENSIBLE WX ACROSS SRN NEW ENGLAND. AGREE WITH THE
PREVIOUS FORECASTER THAT AN ENSEMBLE APPROACH IS BEST HERE...AND
GIVEN WPC/S LEANING ON AN ECENS ENSEMBLE MEAN...WILL BE FOLLOWING
SUIT WITH THIS UPDATE. THE OVERALL RESULT WILL BE THE RISK FOR
MORE WET/GRAY CONDITIONS MID-LATE WEEK AS A BAROCLINIC ZONE
SETTLES NEAR NEW ENGLAND S OF THE THE DEVELOPING CUTOFF.

DETAILS...

SAT AND SAT NIGHT...
FILLING OCCLUSION WILL BE SHIFTING E OF THE REGION AND GRADUALLY
ALLOWING MORE DRY AIR THROUGH THE COLUMN. AFTER A
DAMP/SHOWERY/DRIZZLE START TO THE DAY...SOME BREAKS ARE EXPECTED
IN THE AFTERNOON AND EVENING...WITH EVEN THE LOW POSSIBILITY OF A
FEW PEAKS OF SUN. WITH FLOW SHIFTING S...TEMPS WILL BE MODERATING
ALLOWING FOR A FEW MORE 50S AND LOW 60S THAN PREVIOUS DAYS WITH
LOWS NOW FALLING INTO THE 40S.

SUN...
STRONG COLD FRONT WILL SWEEP THROUGH THE REGION DURING THE MID
DAY PERIOD. THE COMBINATION OF PWATS APPROACHING AN INCH WITH A
MODEST ELEVATED UNSTABLE LAYER BETWEEN H9 AND H7 SUGGESTS SOME
SHRA COULD BE BRIEFLY HEAVY AT TIMES...PARTICULARLY ACROSS THE NRN
HALF OF THE AREA...CLOSER TO THE INFLUENCE OF A LLJ. SOME WETTING
PRECIP EXPECTED ACROSS ALL OF SRN NEW ENGLAND HOWEVER...WITH
HIGHEST TOTALS MAINLY N OF THE MASS PIKE IN THE 0.25-0.50 RANGE
WITH LOCALLY HIGHER AMOUNTS.

MON...
BRIEF REPRIEVE FROM EXPECTED RAINFALL WITH COLD FRONT SHIFTING E
OF THE REGION...ALLOWING A DRIER...BUT COLDER AIRMASS TO SPILL
ACROSS SRN NEW ENGLAND. BREEZY NW FLOW EXPECTED WITH SOME CLOUD
COVER...THE RESULT OF A SECONDARY SHORTWAVE MOVING THROUGH LATE IN
THE DAY. TEMPS MAINLY NEAR TO BELOW SEASONAL NORMALS.

TUE...
CONFIDENCE IN THE FORECAST DROPS RAPIDLY AT THIS POINT DUE TO A
WIDE ARRAY OF POSSIBILITIES FOR A BAROCLINIC ZONE AND UPPER LVL
CUTOFF. FOR NOW...FEEL THAT WITH A DRY COLUMN TO START...TUE WILL
ITSELF BE MAINLY DRY BUT TRANSITIONING BACK TO GRAY/DAMP
CONDITIONS LATE. ECENS/GEFS PROBABILITIES FOR PRECIP ARE RATHER
LOW...HENCE THE DECISION TO LEAN CLOSER TO A DRY FORECAST FOR TUE.
TEMPS WILL BE DETERMINED BY THE FINAL LOCATION OF THE BAROCLINIC
ZONE.

LATE WEEK...
ALTHOUGH NOT LIKELY AS PERSISTENTLY GRAY AND DAMP AS THIS
WEEK...A SHIFT IN THE PATTERN SUGGESTS THAT SEVERAL WAVES ACTING
ALONG THE BAROCLINIC ZONE COULD PROVIDE PERIODS OF RAIN AND EVEN
SOME POSSIBLE THUNDER. OVERALL..NOT AS COLD AS THIS WEEK THANKS TO
INFLUENCE OF THE SRN STREAM WITH THIS FEATURE.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...

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

2030Z UPDATE...

SHORT TERM /THROUGH FRIDAY NIGHT/...

OVERNIGHT...MODERATE CONFIDENCE.
IFR AND LOWER END MVFR CIGS CONTINUE...BUT GRADUALLY RISE TO UPPER
END IFR AND UPPER END MVFR BY THE EARLY MORNING HOURS. AREAS OF
FOG AND DRIZZLE ESPECIALLY IN EASTERN AND CENTRAL SECTIONS. WINDS
SLOWLY DIMINISHING. RAIN HEADS NORTHEAST AND OFF THE COAST AROUND
OR SHORTLY AFTER MIDNIGHT.

FRIDAY...AREA OF IFR WITH POSSIBLE DRIZZLE EARLY. THEN CONDITIONS
IMPROVING TO MVFR. SHOWERS LIKELY IN CT AND WESTERN MA IN THE
AFTERNOON WITH A CHANCE OF SHOWERS ELSEWHERE. ENE WINDS BECOMING E
OR ESE LATE...GUSTING TO 20-25 KT ALONG THE SOUTH COAST LATE.

FRIDAY NIGHT...MORE OF THE SAME. IFR AND LOW-END MVFR WITH
SCATTERED SHOWERS EAST AND SHOWERS LIKELY WEST. CANNOT RULE OUT AN
ISOLATED THUNDERSTORM SOMEWHERE ACROSS THE REGION.

KBOS TERMINAL...MODERATE CONFIDENCE CONCERNING THE TAF. IFR IN
RAIN THROUGH ABOUT 02-03Z THEN RAIN ENDING AND CONDITIONS SLOWLY
IMPROVING TO MVFR CIGS TOWARD DAYBREAK...CONTINUING THROUGH FRI.

KBDL TERMINAL...MODERATE TO HIGH CONFIDENCE IN TAF. MVFR CIGS.
RAIN EXPECTED TO REMAIN TO THE EAST TONIGHT BUT SHOWERS DEVELOPING
AFTER NOON ON FRI. CANNOT RULE OUT AN ISOLATED THUNDERSTORM FRI
NIGHT.

OUTLOOK /SATURDAY THROUGH TUESDAY/...

SAT...HIGH CONFIDENCE.
MIX OF MVFR/IFR GIVES WAY TO MORE WIDESPREAD VFR LATER IN THE DAY
AS RAIN/DRIZZLE COMES TO AN END.  LOW RISK OF A MID DAY TS.

SUN...MODERATE CONFIDENCE.
VFR TO START THE DAY...BUT MIX OF SHOWERS WITH MVFR CONDITIONS
THROUGH MID AFTERNOON WITH A COLD FRONTAL PASSAGE. VFR FOLLOWS
INTO SUN NIGHT.

MON AND TUE...HIGH CONFIDENCE.
MAINLY VFR WITH BRIEF RIDGE OF HIGH PRES.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

430 PM UPDATE...

TONIGHT...HAVE CONTINUED THE GALE WARNINGS FOR ALL COASTAL WATERS
THIS EVENING BUT HAVE ENDED ALL GALES BY 09Z LATE TONIGHT. AT THAT
TIME...THEY WILL NEED TO BE CONVERTED TO SMALL CRAFT ADVISORIES
FOR AT LEAST THE OUTER WATERS.

BUZZARDS BAY TOWER HAS INCREASED TO 39 KT GUSTS FROM 36 KT GUSTS
EARLIER AND BOSTON LIGHT WAS GUSTING TO NEAR GALE AT 31 KT.
MESOSCALE MODELS SHOW AN INCREASE IN WINDS THIS EVENING...THEN
DIMINISHING AFTER 10 PM OR SO...HENCE THE REASON FOR KEEPING GALE
WARNINGS POSTED EARLY TONIGHT. WAVES WILL BUILD TO 9 TO 11 FT OVER
THE OUTER WATERS. VISIBILITIES WILL BE REDUCED TO 1 TO 3 MILES IN
RAIN...DRIZZLE...AND AREAS OF FOG TONIGHT.

FRIDAY...ANOTHER LOW PRESSURE SYSTEM WILL MOVE FROM OFF THE
DELMARVA COAST TO NEW JERSEY. THIS WILL RESULT IN EAST WINDS
INCREASING AS THE DAY PROGRESSES...PERHAPS TO 20-25 KT. THERE WILL
ALSO BE RENEWED CHANCES OF SHOWERS...ESPECIALLY ALONG THE SOUTH
COAST IN THE AFTERNOON. SEAS...MAINLY SWELLS...OF 6 TO 9 FT
CONTINUING.

FRIDAY NIGHT...CONTINUED CHANCES OF SHOWERS AND AN OUTSIDE CHANCE
OF AN ISOLATED THUNDERSTORM TOWARD DAYBREAK. VISIBILITIES GREATLY
REDUCED IN AREAS OF FOG AND DRIZZLE. WINDS TURNING BACK TO THE
NORTHEAST BUT LESS THAN 20 KT. SEAS SLOWLY SUBSIDING TO 5-7 FT
OVER THE OUTER WATERS.

OUTLOOK /SATURDAY THROUGH TUESDAY/...MODERATE CONFIDENCE.

SAT AND SUN...
ALTHOUGH WINDS WILL BE SHIFTING TO THE S AND RECEDING...LINGERING
SWELL ON THE OCEAN WATERS REMAINS NEAR 5-6FT. THEREFORE...SMALL
CRAFT ADVISORIES ARE LIKELY TO LINGER FOR AT LEAST SEAS.

MON AND TUE...
HIGH PRES BRIEFLY BUILDS OVER THE WATERS BUT WITH SUSTAINED NW
FLOW SEAS HOLD NEAR 5 FT ON THE OCEAN WATERS. QUIETER BOATING
WEATHER CLOSER TO SHORE.

&&

.TIDES/COASTAL FLOODING...

1015 PM UPDATE...

SURGE FORECAST FROM PREVIOUS SHIFT SPOT ON...RUNNING AROUND A FT
OR JUST ABOVE. AT 1006 PM BOSTON WAS AT 12.45 FT WITH A SURGE OF
1.1 FT. EXPECTING BOSTON TO TOP OUT AROUND 13 FT. IN ADDITION WAVE
ACTION RUNNING ABOUT 8 TO 11 FT JUST OFFSHORE. THIS COMBINATION OF
ELEVATED WATER LEVELS AND WAVE ACTION SHOULD RESULT IN WIDESPREAD
MINOR COASTAL FLOODING OF THE TYPICAL SHORELINE ROADS OF EASTERN
MA. EARLIER DISCUSSION BELOW.

===================================================================

COASTAL FLOOD ADVISORY REMAINS IN EFFECT FOR BOSTON SOUTH TO
NANTUCKET INCLUDING PLYMOUTH COUNTY AND BOTH THE BAY AND OCEAN
SIDES OF CAPE COD. HAVE EXTENDED THE COASTAL FLOOD ADVISORY TO
ALSO INCLUDE THE ESSEX COUNTY COAST...BUT REALLY ONLY FOR
SALISBURY TO CAPE ANN. THIS PROVIDES CONTINUITY WITH THE COASTAL
FLOOD ADVISORY ISSUED FOR THE NH SEACOAST AND APPEARS WARRANTED
GIVEN FETCH ACROSS THE GULF OF MAINE.

ASTRO HIGH TIDE AT BOSTON IS 11.95 FT AT 1055 PM. HIGHER
RESOLUTION MODELS INDICATE NE WINDS INCREASING A TAD THIS
EVENING...NEAR MINIMAL GALE AT LEAST IN GUSTS ALONG THE MA E
COAST WITH A REASONABLY SIZABLE FETCH ACROSS THE GULF OF MAINE.
ANTICIPATE THE STORM SURGE TO RUN GENERALLY 1 TO 1.5 FT AT THE
TIME OF THE EVENING HIGH TIDE. SEAS ACROSS IPSWICH BAY...MASS BAY
AND OPEN AREA OF NORTHERN CAPE COD BAY EXPECTED TO BE MOSTLY 8 TO
10 FT. AT 4 PM GULF OF MAINE BUOY REPORTED 10 FOOT SEAS AND THOSE
WILL LIKELY PROPAGATE CLOSER TO CAPE ANN AND INTO AT LEAST
STELLWAGEN BANK AND PORTIONS OF MASS BAY THIS EVENING. SEAS OF 10
TO 12 FT EXPECTED EAST OF CAPE COD. THIS SETS UP THE LIKELIHOOD
FOR MINOR COASTAL FLOODING ALONG THE MA E AND NE FACING SHORELINES
FROM SALISBURY TO CAPE ANN...BOSTON TO PLYMOUTH TO
DENNIS...ORLEANS AND CHATHAM...AND NANTUCKET HARBOR. INUNDATION
WILL BE FROM A COMBINATION OF HIGH TOTAL WATER LEVEL AND WAVE
SPLASHOVER. MINOR EROSION IS POSSIBLE BUT WOULD NEED GREATER WAVE
ACTION FOR A MORE SERIOUS EROSION CONCERN.

AT LEAST POCKETS OF MINOR COASTAL FLOODING ARE POSSIBLE FOR THE
MA EAST COAST FOR THE FRIDAY LATE EVENING HIGH TIDE DUE TO AN
EVEN HIGHER ASTRO TIDE AND A RESIDUAL SURGE. WEAK ONSHORE WINDS
AND A LINGERING SWELL ARE EXPECTED TO KEEP A .5 TO 1.0 FOOT SURGE
PERSISTING THROUGH THE FRIDAY EVENING HIGH TIDE.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...COASTAL FLOOD ADVISORY UNTIL 1 AM EDT FRIDAY FOR MAZ007-015-
     016-019-022-024.
RI...NONE.
MARINE...GALE WARNING UNTIL 5 AM EDT FRIDAY FOR ANZ231>235-237-250-251-
     254>256.
     GALE WARNING UNTIL 2 AM EDT FRIDAY FOR ANZ230-236.

&&

$$
SYNOPSIS...DOODY/GAF
NEAR TERM...NOCERA/DOODY/GAF
SHORT TERM...GAF
LONG TERM...DOODY
AVIATION...DOODY/GAF
MARINE...DOODY/GAF
TIDES/COASTAL FLOODING...THOMPSON/NOCERA


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