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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBOX 180805
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
405 AM EDT TUE JUN 18 2013

.SYNOPSIS...

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ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS IS ANTICIPATED TODAY
INTO TONIGHT AHEAD OF A REINFORCING COLD FRONT PUSHING SOUTH
ACROSS NEW ENGLAND. HIGH PRESSURE WILL FOLLOW THEREAFTER BRINGING
MAINLY DRY AND SEASONABLE CONDITIONS WEDNESDAY THROUGH SATURDAY.
THE HIGH WILL THEN ANCHOR ITSELF SOUTH OF NEW ENGLAND THIS
WEEKEND...YIELDING A TREND TOWARD WARMER AND MORE HUMID WEATHER.
AN APPROACHING WARM FRONT MAY BRING WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS NEXT WEEKEND.
-- End Changed Discussion --

&&

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

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4 AM UPDATE...

ISOLATED SHOWERS CONTINUE TO PUSH ACROSS THE REGION. MEANWHILE FOG
AND LOW CLOUDS HAVE BECOME PROBLEMATIC. HAVE ADJUSTED THE FORECAST
ACCORDINGLY. EXPECTING ANY FOG AND LOW CLOUDS TO BURN OFF WITH
SUNRISE.

TODAY...

A COLD FRONT ALONG THE LEADING EDGE OF A DEEPER COLD POOL WILL PUSH
SOUTH ACROSS NEW ENGLAND ALONG AND AHEAD SHOWERS AND THUNDERSTORMS
WILL RENEW.

CONSIDERING THE ENVIRONMENT...BULK SHEAR IS PRONOUNCED WITH VALUES
OF AROUND 40 KTS THROUGH 0-6 KM...ROUGHLY PARALLEL TO THE SURFACE
COLD FRONT INDICATING FAVORABILITY TO LINE RATHER THAN DISCREET
THUNDERSTORMS /SIMILAR TO WHAT WE SAW YESTERDAY/. THERE IS SOME
SLIGHT INDICATION OF TURNING WITHIN 0-3 KM...WHICH WOULD SUPPORT
ROTATING UPDRAFTS. SHOULD BE PLENTY OF LIFT AS THE COLD FRONT IS
PARENT WITH MID-LEVEL ENERGY PROVIDING ENHANCED ASCENT COUPLED WITH
THE RIGHT-REAR QUADRANT OF THE UPPER-LEVEL JET. MEANWHILE...THE 0Z
CHATHAM SOUNDING IS INDICATIVE OF A PRIME ENVIRONMENT WITH FAIRLY
STEEP LAPSE RATES FROM THE LOW-LEVEL INVERSION AROUND H9 UP TO H6.

BUT THE OUTCOMES LOOK RATHER MESSY. THE POTENTIAL EARLY INITIATION
CLOSER TO MIDDAY AS INDICATED BY THE 18.0Z WRF AND 18.04Z HRRR/RUC
SUGGEST LESS AVAILABLE INSTABILITY DUE TO LESS DESTABILIZATION. AS
THE COLD FRONT PUSHES SOUTH...EXPECTING MULTI-CELLULAR AND LINE-ECHO
WAVE PATTERN THUNDERSTORMS EMBEDDED WITHIN A WIDESPREAD AREA OF
RAIN. THE SUBSTANTIAL AMOUNT OF LIFT SHOULD RESULT IN SOME HEAVY
RAINERS UTILIZING THE LOCAL ATMOSPHERE WITH PERCEPTIBLE WATER
VALUES OF 1.0 TO 1.5 INCHES.

FEEL THE SEVERE WEATHER THREAT WILL BE LESS COMPARED TO YESTERDAY
BUT CAN NOT RULE OUT THE POTENTIAL OF DEADLY LIGHTNING AND DAMAGING
WINDS. GREATER CONFIDENCE LIES IN THE POTENTIAL FOR LOCALIZED URBAN
AND SMALL STREAM FLOODING. SURELY TO BE PONDING OF WATER ON ROADWAYS
AND REDUCED VISIBILITIES...HAZARDOUS FOR MOTORISTS. EVENING
COMMUTE WILL BE UNDER GREATEST THREAT. FOLLOWING THE PREVIOUS
FORECASTER...WILL APPEND HEAVY RAIN TO THE FORECAST.

MUCH OF THE ACTIVITY SHOULD REMAIN ALONG AND SOUTH OF THE ROUTE 2
CORRIDOR ACROSS NORTHERN MASSACHUSETTS PUSHING SOUTH AND EAST
TOWARDS THE WATERS INTO THE EVENING PERIOD. HIGHS FOR THE DAY WILL
BE AROUND THE LOW TO MID 70S.
-- End Changed Discussion --

&&

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

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TONIGHT...

THE COLD FRONT WILL SLOW AS IT PUSHES OFFSHORE AS A WEAK WAVE LIFTS
ALONG THE FRONT FROM THE MID-ATLANTIC. EXPECTING WIDESPREAD RAIN
WITH EMBEDDED HEAVIER SHOWERS AND THUNDERSTORMS TO LINGER OVER THE
SOUTH COAST AND ADJACENT WATERS. CONCERNS WILL STILL BE PRESENT FOR
LOCALIZED URBAN FLOODING AND PONDING OF WATER ALONG ROADWAYS...BUT
LOW CONFIDENCE ON SEVERE WEATHER THREATS AS INSTABILITY IS EXPECTED
TO BE MINIMAL. LOWS DOWN TO AROUND LOW 50S.

WEDNESDAY...

COOLER AIRMASS BUILDING SOUTH SHOULD ALLOW SIGNIFICANT BOUNDARY
LAYER MIXING OF AROUND 4-6 KFT. SUBSEQUENTLY...ANTICIPATING THE MIX-
DOWN OF FASTER MOMENTUM AND DRIER AIR. NOT LOOKING AT ANY FIRE
WEATHER HEADLINES WITH RECENT RAINS. DEWPOINTS DOWN TO AROUND 50
DEGREES...SOME GUSTY NORTHERLY WINDS MAINLY ACROSS EASTERN NEW
ENGLAND. EXPECTING DIURNAL SCATTERED TO BROKEN FAIR-WEATHER CUMULUS
ACROSS INTERIOR NEW ENGLAND.
-- End Changed Discussion --

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...

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HIGHLIGHTS...

* TEMPS NEAR NORMAL THU AND FRI...TRENDING WARMER/HUMID THIS WEEKEND
* MAINLY DRY WED NGT THROUGH FRI THEN CHANCE OF TSTMS SAT/SUN/MON

00Z DETERMINISTIC MODELS AND 00Z ENSEMBLES ARE IN GOOD AGREEMENT ON
THE LARGE SCALE PATTERN THIS PERIOD...WITH BROAD LOW AMPLITUDE
TROUGH OVER THE NORTHEAST STATES AND SOUTHEAST CANADA PERSISTING
MUCH OF THE REMAINDER OF THE WORK WEEK. HOWEVER WITH THE MEAN TROUGH
AXIS PUSHING OFFSHORE LATER WED...HIGH PRES AND A DRIER AIRMASS
ADVECT ACROSS THE REGION PROVIDING DRY AND SEASONABLE WEATHER FROM
LATE WED THROUGH FRI. IN FACT THU COULD BE THE PICK OF THE
WEEK...STARTING OFF WITH COOL MORNING TEMPS IN THE U40S AND L50S BUT
THEN REBOUNDING INTO THE 70S DURING THE AFTERNOON COURTESY OF
STRONG MID-LATE JUN SUNSHINE.

FRI...A VERY LOW RISK OF AN AFTN/EVENING TSTM AS A WEAK TROUGH
PASSES ACROSS THE AREA. OTHERWISE THE BULK OF WED NGT THROUGH FRI
SHOULD BE DRY.

BY THE WEEKEND ALL MODEL GUIDANCE IN GOOD AGREEMENT ON NORTHERN
BRANCH JET LIFTING NORTHWARD INTO CANADA AS SUBTROPICAL RIDGE BUILDS
FROM THE SOUTHERN PLAINS INTO THE MID ATLC REGION. THIS WILL SUPPORT
A TREND TOWARD WARMER AND MORE HUMID WEATHER FOR SOUTHERN NEW
ENGLAND. IN FACT BY SUN AND/OR MON SOME LOCATIONS ACROSS INTERIOR
SOUTHERN NEW ENGLAND MAY BE PUSHING 90 DEGS AS 00Z ECENS ADVECTS 850
TEMPS OF AROUND +16 INTO THE AREA. CAN/T RULE OUT ISOLATED OR WIDELY
SCATTERED CONVECTION AS WARM SECTOR OVERSPREADS SOUTHERN NEW
ENGLAND...ALTHOUGH NOT EXPECTING A WASHOUT WITH MANY HOURS OF DRY
WEATHER.
-- End Changed Discussion --

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...

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FORECASTER CONFIDENCE LEVELS...

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

NEAR-TERM /THROUGH WEDNESDAY/...MODERATE CONFIDENCE.

GREATER CONFIDENCE OF LOW CLOUDS AND FOG IMPACTING INTERIOR VALLEY
TERMINALS NEAR BODIES OF WATER /RIVER VALLEYS/ AND ALONG THE SOUTH
SHORE INTO THE MORNING HOURS...BURNING OFF WITH SUNRISE. THEN ATTENTION
FOCUSES ON THE RENEWED +RA/TSRA THREAT BY MIDDAY INTO EVENING.
ANTICIPATE LOW-VFR/MVFR CIGS WITH MVFR/IFR VSBYS WITH +RA/TSRA.

VARIABLE WINDS AS A COLD FRONT SLIDES ACROSS THE REGION...MAINLY
SOUTH AND EAST...BACKING OUT OF THE NORTH WITH THE COLD FRONTAL
PASSAGE. ANTICIPATING GRADUAL CLEARING NORTH TO SOUTH OVERNIGHT
INTO WEDNESDAY...BECOMING VFR. PERHAPS SOME GUSTY NORTHERLY WINDS
ALONG EASTERN NEW ENGLAND WEDNESDAY.

KBOS TERMINAL...MODERATE CONFIDENCE. RA/TSRA POSSIBLE MIDDAY INTO
AFTERNOON.

KBDL TERMINAL...MODERATE CONFIDENCE. RA/TSRA POSSIBLE MIDDAY INTO
AFTERNOON.

OUTLOOK...WEDNESDAY NIGHT THROUGH FRIDAY...

HIGH CONFIDENCE FOR VFR AND MAINLY DRY WEATHER.
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&&

.MARINE...

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FORECASTER CONFIDENCE LEVELS...

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

NEAR-TERM /THROUGH WEDNESDAY/...MODERATE CONFIDENCE.

WINDS AND SEAS HAVE DIMINISHED PROMPTING THE CANCELING OF SMALL
CRAFT ADVISORIES ON THE SOUTH-SOUTHEAST OUTER WATERS. WILL SEE A
COLD FRONT SLIDE ALONG WATERS OVERNIGHT TONIGHT ALONG WHICH
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. EXPECT THIS ACTIVITY
TO BE SOUTH OF THE WATERS INTO WEDNESDAY...BEHIND WHICH WINDS WILL
SHIFT OUT OF THE NORTH-NORTHEAST. GUSTS UP TO 25 KTS WILL BE
POSSIBLE SUBSEQUENTLY AMPLIFYING WAVE HEIGHTS OF 5 TO 6 FEET ON
THE OUTER WATERS.

OUTLOOK...WEDNESDAY NIGHT THROUGH FRIDAY...

HIGH CONFIDENCE.

DEPARTING LOW PRES WED OVER GEORGES BANK WILL RESULT IN LEFTOVER NE
SWELLS ACROSS THE OCEAN WATERS. SEAS WILL EVENTUALLY SUBSIDE BY THU
AND ESPECIALLY FRI AS HIGH PRES MOVES OVER THE WATERS. MAINLY DRY
WEATHER EXPECTED THIS PERIOD ALONG WITH GOOD VSBY.
-- End Changed Discussion --

&&

.HYDROLOGY...

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RIVERS CONTINUE TO RECEDE ACROSS THE REGION...WITH MOST FALLING
BELOW FLOOD STAGE YESTERDAY AND OVERNIGHT. ONLY THE CHARLES RIVER AT
DOVER REMAINS IN MINOR FLOOD. LATEST GUIDANCE INDICATES THAT THIS
RIVER WILL ONLY SLOWLY FALL AND REMAIN IN MINOR FLOOD INTO
WEDNESDAY MORNING.

THE MAIN CONCERN WILL BE LOCALLY HEAVY RAINFALL/POOR DRAINAGE STREET
FLOODING FROM EMBEDDED HEAVY RAINS AND THUNDERSTORMS ANTICIPATED
AROUND MIDDAY TODAY INTO THIS AFTERNOON. WILL CONTINUE TO HAVE TO
KEEP AN EYE ON SOME OF THEM ESPECIALLY THE SMALLER STREAMS.
-- End Changed Discussion --

&&

.BOX WATCHES/WARNINGS/ADVISORIES...

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CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
-- End Changed Discussion --

&&

$$

SYNOPSIS...NOCERA/SIPPRELL
NEAR TERM...SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...NOCERA
AVIATION...NOCERA/SIPPRELL
MARINE...NOCERA/SIPPRELL
HYDROLOGY...WFO BOX STAFF