Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 170204
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1004 PM EDT THU OCT 16 2014

.SYNOPSIS...
SCATTERED SHOWERS WILL IMPACT EASTERN MASSACHUSETTS THIS EVENING
WITH PERIODS OF HEAVY RAIN CONFINED TO CAPE COD AND NANTUCKET.
PLEASANT WEATHER IS EXPECTED FRIDAY INTO SATURDAY...WITH MILD
TEMPERATURES CONTINUING. A COLD FRONT WILL SWEEP ACROSS THE REGION
SATURDAY EVENING WITH MUCH COOLER TEMPERATURES BY SUNDAY. HIGH
PRESSURE BUILDS IN EARLY NEXT WEEK. COASTAL LOW WILL DEVELOP TUES-
THURSDAY...A LOT OF UNCERTAINTY ON ITS IMPACT TO SOUTHERN NEW
ENGLAND SO STAY TUNED.

&&

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

***FLASH FLOOD WATCH CONFINED TO CAPE COD AND NANTUCKET UNTIL 11
 PM ***

10 PM UPDATE...

LARGE PLUME OF PRECIP IS IMPACTING THE CAPE AND NANTUCKET AS OF 10
PM. LATEST WATER VAPOR IMAGERY SHOWS COOLING CLOUD TOP MOVING UP
FROM ATLANTIC...HOWEVER APPEARS THAT THE HEAVIEST PRECIP WILL JUST
BE OFFSHORE. ANTICIPATE PRECIP TO CONTINUE OVER THE NEXT FEW HOURS
AS THE NEGATIVE TILTED TROUGH IS PULLING IN THE WARM CONVEYOR
BELT MOISTURE PLUME. LATEST HI-RES GUIDANCE SHOWS THAT THE PRECIP
WILL MOVE OFFSHORE CLOSER TO 6Z WITH THE SHORTWAVE TROUGH
CONTINUES ITS EASTWARD TRACK.

OTHERWISE WITH DEEP MOISTURE PLUME CONFINED TO CAPE COD AND
NANTUCKET...LIGHTER NUISANCE TYPE SHOWERS ARE POSSIBLE ACROSS RI
AND EASTERN MA. MEANWHILE...CLEARING LINE IS BACK ACROSS THE
BERKSHIRES OF WESTERN MA...CENTRAL CT TO BLOCK ISLAND. THIS WILL
LIKELY FILL BACK IN OVERNIGHT AS MID/UPPER TROUGH SWINGS ACROSS
THE AREA.

MILD BUT NOT AS WARM OR HUMID AS LAST NIGHT AS DEW PTS IN THE 50S
ADVECT ACROSS THE REGION OVERNIGHT. HOWEVER GIVEN THE HEAVY
RAINFALL FROM TODAY AND SLACKENING WINDS EXPECT PATCHY DENSE FOG
OVERNIGHT.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
FRIDAY...

A BEAUTIFUL DAY OF WEATHER ON TAP TO CLOSE OUT THE WORK WEEK.  ANY
LOW CLOUDS/FOG PATCHES SHOULD BURN OFF BY MID TO LATE MORNING.
PARTLY TO MOSTLY SUNNY SKIES EXPECTED WITH SOUTHWEST FLOW ALOFT
CONTINUING.  THEREFORE...TEMPS WILL REMAIN MILD FOR THIS TIME OF
YEAR.  HIGHS SHOULD RANGE FROM THE UPPER 60S ACROSS THE HIGHER
TERRAIN...TO THE LOWER 70S ELSEWHERE.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
HEADLINES...

*SCATTERED SHOWERS POSSIBLE DURING THE WEEKEND
*MONDAY HAS BEST CHANCE TO REMAIN DRY...BUT WILL BE CLOUDY
*COASTAL STORM DEVELOPS TUES AND STAYS THROUGH THURS

OVERVIEW...

AN AMPLIFIED PATTERN OVER THE UNITED STATES BRINGS A RIDGE OVER THE
WESTERN STATES AND A TROUGH OVER THE EASTERN STATES. AN UPPER LEVEL
LOW OVER THE EASTERN UNITED STATES SERVES AS THE POINT THAT
SHORTWAVES ARE ABLE TO PINWHEEL AROUND FOR THE WEEKEND. AS THE UPPER
LEVEL LOW SLOWLY LEAVES THE STATES ANOTHER SHORTWAVE DIVES OUT OF
CANADA AND DEVELOPS INTO A COASTAL LOW INSIDE THE TEMPERATURE
GRADIENT ALONG THE EAST COAST. THIS SETS UP ANOTHER PERIOD OF WEAK
SHOWERS WHERE MODEL DISCREPANCIES AGAIN RESULT.

MODELS HAVE A HARD TIME HANDLING THE WEEKEND/S AND LATE WEEK/S
PRECIPITATION FROM THE UPPER LEVEL LOWS/ SLOW MOVEMENT. AS IS
FREQUENTLY SEEN IN MODEL EVOLUTION...VORTICITY IS NOT HANDLED WELL
FAR INTO THE FUTURE. SO EXACT PLACEMENT OF THE PRECIPITATION FOR
NEXT WEEK/S COASTAL LOW HAS LOW CONFIDENCE ASSOCIATED WITH IT.

DAILIES...

SATURDAY...AN UPPER LEVEL AND IT/S ASSOCIATED SHORTWAVE OVER THE
NORTHERN MIDWEST MOVES EAST AND THEN PINWHEELS AROUND THE UPPER
LEVEL LOW OVER THE NORTHEAST. WITH THE COLD AIR ALOFT...AN
APPROACHING COLD FRONT AND THE AFOREMENTIONED SHORTWAVE...SHOWERS
SHOULD RESULT ESPECIALLY LATER IN THE DAY. THEY LOOK TO BE ON THE
WEAKER END OF THE SPECTRUM AND SCATTERED AT BEST. SOME SMALL HAIL
COULD BE SEEN WITH THE COLDER AIR ALOFT AND THE FREEZING LEVEL
CLOSER TO THE SURFACE THAN NORMAL. SUNNY PEAKS SHOULD BE SEEN DURING
THIS PERIOD. WITH 850MB TEMPS AROUND 9C...COULD SEE SFC TEMPS IN THE
LOW 70S DURING THE DAY AHEAD OF THE FRONT. WITH MIXING TO 850MB WIND
GUSTS COULD GET TO 25 MPH.

SUNDAY...SMALL CHANCE OF SHOWERS IN THE MORNING. AFTER THE COLD
FRONT...COOLER AIR IS ABLE TO SPILL IN. CLOUDS THIN OUT TOWARDS MID
AFTERNOON AND DRYING OCCURS. WITH 850 TEMPS AROUND -4C...SFC TEMPS
SHOULD STAY IN THE LOW TO MID 50S. THAT/S AROUND A 20F TEMP SWING IN
TERMS OF HIGH TEMPS THANKS TO THE COLD FRONT. WITH MIXING TO 850MB
WIND GUSTS COULD GET TO 30 MPH.

MONDAY...RIDGING OCCURS AS A HIGH PRESSURE SYSTEM SCOOTS SOUTH OF
THE REGION. THIS KEEPS THE REGION DRY. TEMPS COULD GET INTO THE MID
50S WITH LESS OF A NORTHERLY FLOW.

TUESDAY THROUGH THURSDAY...THIS PERIOD INCLUDES QUITE A BIT OF
UNCERTAINTY. ENSEMBLES ARE SMOOTHING OVER A LOT OF UNCERTAINTY
ESPECIALLY IN TERMS OF SURFACE PRESSURE AND TIMING. THE GENERAL
PATTERN FOR THIS TIME PERIOD EVOLVES AS ANOTHER SHORTWAVE DIVES
SOUTH OUT OF CANADA. IT THEN PINWHEELS AROUND THE BOTTOM OF THE
TROUGH FORMED BY THE UPPER LEVEL LOW. AS THE UPPER LEVEL CENTERED IN
SOUTHEAST CANADA QUICKLY MOVES NORTHEAST TO GO OFFSHORE...A SPACE
OPENS UP FOR DEVELOPMENT ALONG THE EAST COAST. THE QUESTION THEN
BECOMES IF THE SHORTWAVE CAN DEVELOP INTO AN UPPER LEVEL LOW. THE
ECENS HAS IT DOING JUST THAT...BUT THE GEFS HAS MORE SPREAD WITH A
POSITIVE TILT IN THE HEIGHTS. NORTHEAST FLOW DOES OCCUR IN ENSEMBLES
ESPECIALLY LATER TUESDAY AS THE COASTAL LOW IS SOUTH OF THE REGION.
AS IT PULLS TO THE EAST...NORTHWEST FLOW COMES IN LATE THURSDAY.
RAIN LOOKS LIGHT...BUT STEADY OVER THIS PERIOD ESPECIALLY FROM LATER
TUESDAY THROUGH MOST OF THURSDAY.

&&

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

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

SHORT TERM /THROUGH FRIDAY/...MODERATE CONFIDENCE TONIGHT AND HIGH
CONFIDENCE ON FRIDAY.

7 PM UPDATE...

NO WHOLESALE CHANGES FROM 18Z TAFS. IMPROVING TRENDS CONTINUE WITH
HEAVY RAIN CONFINED TO CAPE COD AND NANTUCKET. THUNDERSTORMS WELL
SOUTH OF NEW ENGLAND MAY CLIP NANTUCKET AND CAPE COD THRU AT LEAST
03Z AND POSSIBLY 06Z BEFORE MOVING WELL OFFSHORE. EARLIER
DISCUSSION BELOW.

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

TONIGHT...MVFR CONDITIONS DOMINATE THIS EVENING WITH PERIODS OF IFR
CONDITIONS ALONG EASTERN NEW ENGLAND WHERE THE HEAVY RAIN WILL BE
FOCUSED.  LOW PROBABILITY OF AN ISOLATED THUNDERSTORM THROUGH 00Z.
CONDITIONS IMPROVE EVEN IN THE EAST AFTER 00Z...BUT SCATTERED
SHOWERS MAY PERSIST.  ACROSS THE INTERIOR...TEMPORARY IMPROVEMENT TO
VFR IS POSSIBLE BUT LOW CLOUDS AND PATCHY FOG MAY RE-DEVELOP.

KBOS...MODERATE TO HIGH CONFIDENCE IN MVFR WITH PERIODS OF IFR
CONDITIONS THROUGH 00Z.  MAINLY MVFR TO PERHAPS EVEN VFR AFTER 00Z.

KBDL...MODERATE CONFIDENCE.  MVFR CONDITIONS THIS EVENING.  MAY SEE
IMPROVEMENT TO VFR FOR A TIME THIS EVENING...BUT WILL HAVE TO WATCH
FOR LOWER CLOUDS AND PATCHY FOG MOVING INTO THE REGION OVERNIGHT.

OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...

SATURDAY AND SUNDAY...MODERATE CONFIDENCE. VFR FOR MOST LOCATIONS.
ISOLATED MVFR IN DIURNAL SHOWERS FOR BOTH DAYS. GUSTY WESTERLY WINDS
UP TO 20 KTS...25 KTS ON SUNDAY.

MONDAY...MODERATE CONFIDENCE. VFR.

TUESDAY...MODERATE CONFIDENCE...RAIN OVERSPREADS THE REGION
ESPECIALLY LATE IN THE DAY. WINDS TURN NE DURING THE DAY AS THE
COASTAL STORM DEVELOPS.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /TONIGHT THROUGH FRIDAY/...HIGH CONFIDENCE.

7 PM UPDATE...

STRONGEST SSE WINDS HAVE MOVED EAST OF NANTUCKET AND CAPE COD AS
OF 7 PM. HOWEVER LARGE SOUTHERLY WIND WAVES CONTINUE ON THE
SOUTHERN OCEAN WATERS WITH SEAS OF 5 TO 9 FT. SWELLS FROM
HURRICANE GONZALO STILL WELL SOUTH OF NEW ENGLAND. HEAVY RAIN AND
THUNDERSTORMS TONIGHT SHOULD BE CONFINED TO NANTUCKET...CAPE COD
AND POINTS EASTWARD...THEN WELL OFFSHORE AFTER 2 AM OR SO. EARLIER
DISCUSSION BELOW.

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

TONIGHT...LOW LEVEL JET WILL CONTINUE TO RESULT IN SOUTHERLY WIND
GUSTS OF 20 TO 25 KNOTS INTO THE EVENING OVER THE OPEN WATERS.
WINDS SHOULD DIMINISH SOME BY LATE EVENING AS LOW LEVEL JET WEAKENS
AND SHIFTS EAST OF THE REGION...BUT SCA SEAS WILL CONTINUE.  HEAVY
SHOWERS AND AN EMBEDDED THUNDERSTORM OR TWO WILL LOWER VISIBILITIES
AT TIMES.

FRIDAY...SOUTHWEST WIND GUSTS OF 20 TO 25 KNOTS ARE EXPECTED WITH
GOOD MIXING BEHIND THE FRONT PARTICULARLY NEAR SHORE.
HOWEVER...SEAS OF 5 TO 8 FEET EXPECTED ACROSS THE OPEN WATERS AS A
RESULT OF SOUTHEAST SWELL FROM DISTANT HURRICANE GONZALO.  SCA
HEADLINES CONTINUE FOR MOST OPEN WATERS.

OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...

SATURDAY...MODERATE CONFIDENCE...AS GONZALO PASSES SOUTHEAST OF THE
REGION...EXPECT SEA SWELLS TO GO ABOVE SCA THRESHOLD AND WINDS TO GO
ABOVE SCA THRESHOLD. SCA WILL BE NEEDED.

SUNDAY...MODERATE CONFIDENCE. GUSTY WEST WINDS AROUND 30KTS WILL
IMPACT THE WATERS AS WELL. STILL EXPECTING ROUGH SEAS AS CAA COMES
IN AND INTERACTS WITH THE LEFTOVER SOUTHEAST SEA SWELLS FROM
GONZALO. SCA WILL STILL PROBABLY NEEDED FOR THIS PERIOD.

MONDAY...MODERATE CONFIDENCE. HIGH PRESSURE WILL SLIDE SOUTH OF THE
WATERS REDUCING WIND SPEEDS TO 20 KT GUSTS. SEAS WILL REMAIN UP TO
AROUND 5 FT ACROSS THE OUTER WATERS.

TUESDAY...WINDS AND SEAS REMAIN BELOW SCA THRESHOLD. WIND GUSTS
APPROACH 25 KTS AND SWELLS BEGIN TO RISE AS THE COASTAL STORM
DEVELOPS LATE

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR MAZ022-024.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
     ANZ231>234.
     SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ235-237-
     254>256.
     SMALL CRAFT ADVISORY UNTIL 8 AM EDT SATURDAY FOR ANZ250.

&&

$$
SYNOPSIS...FRANK/99
NEAR TERM...NOCERA/DUNTEN
SHORT TERM...FRANK
LONG TERM...FRANK/99
AVIATION...FRANK/NOCERA/99
MARINE...FRANK/NOCERA/99



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