Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 280205
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1005 PM EDT WED MAY 27 2015

.SYNOPSIS...
SHOWERS AND ISOLATED THUNDERSTORMS WILL DIMINISH THIS
EVENING...WITH MAINLY DRY CONDITIONS EXPECTED AFTER MIDNIGHT. A
COLD FRONT MAY BRING A FEW STRONG THUNDERSTORMS TO THE REGION
THURSDAY AFTERNOON BUT A WIDESPREAD/SOAKING RAINFALL IS NOT
EXPECTED. DURING FRIDAY HIGH PRESSURE WILL BRING DRY CONDITIONS.
FOR THIS WEEKEND...A SLOW MOVING FRONT WILL BRING THE CHANCE FOR
SHOWERS AND SOME THUNDERSTORMS. THIS FRONT MAY LINGER NEAR OUR
AREA INTO THE BEGINNING OF THE NEXT WORKWEEK...WITH HIGH PRESSURE
RETURNING BY MIDWEEK.

&&

.NEAR TERM /THROUGH THURSDAY/...

1000 PM UPDATE...

PRECIPITATION IS DISSIPATING AS IT MOVES EASTWARD THANKS TO MID-
LEVEL DRY AIR PER 00Z SOUNDING OUT OF CHH. K INDEX ALSO DROPS OFF
SIGNIFICANTLY SO ANTICIPATE THAT RI AND LOCATIONS ACROSS METROWEST
POINTS EASTWARD WILL REMAIN DRY. ANY PRECIP TONIGHT WILL BE LIGHT
AND DROP PERHAPS A FEW HUNDREDTHS OF AN INCH. CONVECTIVE CLOUDS
CONTINUE TO STREAM ACROSS THE REGION BUT SHOULD BEGIN TO DISSIPATE LATE
TONIGHT. MAY HAVE TO WATCH FOR PATCHY FOG ACROSS THE CT VALLEY AS
PRECIP ADDED LOW LEVEL MOISTURE TO THE PROFILE AND WITH DRY AIR
MOVING ALOFT COULD CREATE A SUBTLE INVERSION.

AFTER MIDNIGHT...SHOULD SEE LOW CLOUDS INCREASE OVERNIGHT BUT
AREAL COVERAGE IS VERY UNCERTAIN WITH HIGHEST RISK ACROSS SOUTH OF
MA PIKE. WINDS DO NOT TOTALLY DECOUPLE IN MOST LOCATIONS...SO
WHILE SOME FOG PATCHES ARE POSSIBLE ESPECIALLY NEAR THE SOUTH
COAST ITS EXTENT SHOULD BE LIMITED TO SOME DEGREE. LOW TEMPS WILL
NOT DROP BELOW 65 DEGREES IN MANY LOCATIONS AS A RESULT OF
INCREASING LOW LEVEL MOISTURE.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH 6 PM THURSDAY/...
*** A FEW STRONG TO MARGINALLY SEVERE THUNDERSTORMS POSSIBLE
  THURSDAY AFTERNOON/EARLY EVENING BUT A WIDESPREAD OUTBREAK IS NOT
  EXPECTED ***

THURSDAY...

ANY LOW CLOUDS AND FOG PATCHES SHOULD MIX OUT ACROSS MOST OF THE
REGION BY LATE MORNING.  THIS A RESULT OF WINDS VEERING AT LEAST A
BIT AHEAD OF A PRE-FRONTAL TROUGH/COLD FRONT.  THE EXCEPTION TO THIS
WILL BE THE SOUTH COAST/CAPE/ISLANDS...WHERE MARINE INFLUENCE MAY
ALLOW LOW CLOUDS/FOG PATCHES TO HANG ON MUCH OF THE AFTERNOON.

OTHERWISE...SHOULD SEE PARTIAL SUNSHINE EMERGE.  MILD START AND WITH
850 MB TEMPS AROUND +15C TO +16C SHOULD ALLOW HIGHS TO REACH INTO
THE MIDDLE TO UPPER 80S NORTHWEST OF BOS TO PVD LINE.  IN FACT...MAY
SEE A FEW LOCATIONS NEAR 90 IN THE MERRIMACK RIVER VALLEY.  TEMPS
WILL BE COOLER SOUTHEAST OF A BOS TO PVD LINE GIVEN THE MARINE
INFLUENCE ON GUSTY SOUTHWEST WINDS.

THE MAIN CONCERN THURSDAY AFTERNOON AND EARLY EVENING WILL THE
POTENTIAL FOR A FEW STRONG TO MARGINALLY SEVERE THUNDERSTORMS.
CAPES SHOULD INCREASE ON THE ORDER OF 1000 TO 2000 J/KG AHEAD OF AN
APPROACHING PRE-FRONTAL TROUGH/COLD FRONT.  IN ADDITIONAL...0 TO 6
KM SHEAR ON THE ORDER OF 30 TO 35 KNOTS WITH MID LEVEL LAPSE RATES
STEEPENING A LAPSE RATES SHOULD ALLOW SOME SCATTERED
SHOWERS/THUNDERSTORMS TO DEVELOP DURING THE AFTERNOON.  THIS WILL
FIRST OCCUR IN THE INTERIOR AND THEN MAKE THEIR WAY TOWARDS THE
COASTAL PLAIN LATER IN THE AFTERNOON/EARLY EVENING WITH THE PRE-
FRONTAL TROUGH COLD FRONT.  ENOUGH 0 TO 6 KM SHEAR AND 500 MB TEMPS
DROPPING TO AROUND -12C...MAY ALLOW FOR A FEW STRONG TO SEVERE
THUNDERSTORMS.  WHILE WE ARE NOT EXPECTING A WIDESPREAD/HIGH END
OUTBREAK...A FEW STORMS MAY CONTAIN LOCALLY STRONG TO DAMAGING WIND
GUSTS AND HAIL.  LOCALLY HEAVY RAINFALL WILL ALSO BE A CONCERN...AS
IT TYPICALLY IS WITH THUNDERSTORMS.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
DETAILS...

THURSDAY NIGHT...COLD FRONT MOVES OFFSHORE THURSDAY EVENING. SLIGHT
CHANCE OF SHOWERS/THUNDER EARLY ACROSS EAST AND SOUTH COASTAL AREAS
WITH THE FRONT...THEN PRECIP CHANCES COME TO AN END AND HIGH
PRESSURE STARTS TO BUILD INTO OUR AREA. THE POTENTIAL EXISTS FOR
AREAS OF FOG TO DEVELOP ALONG SOUTH COASTAL MA AND RI.

FRIDAY...UPPER LEVEL RIDGING AND PASSING SURFACE HIGH PRESSURE BRING
A MAINLY DRY DAY TO SOUTHERN NEW ENGLAND. A BIT LESS WARM WITH HIGHS
IN THE UPPER 70S TO LOW 80S...EXCEPT ONSHORE WINDS KEEP TEMPS LOWER
CLOSE TO THE SHORELINE.

SATURDAY...SURFACE HIGH PRESSURE SLIDES OFFSHORE...ENABLING
SOUTHWEST FLOW TO BRING INCREASING MOISTURE/HUMIDITY TOWARDS OUR
AREA. LATE IN THE DAY A COLD FRONT APPROACHES OUR REGION FROM THE
WEST...EMERGING FROM THE EASTERN GREAT LAKES REGION AND QUEBEC.  WE
COULD SEE SCATTERED SHOWERS/THUNDERSTORMS DURING SATURDAY AFTERNOON
IN WESTERN MA AND NORTHERN CT...WITH SHOWER/THUNDERSTORM CHANCES
EXTENDING EASTWARD SATURDAY EVENING AS THE COLD FRONT PUSHES INTO
OUR AREA. WITH PRECIPITABLE WATER INCREASING TO OVER 1.5 INCHES
AHEAD OF THE FRONT...LOCALLY HEAVY DOWNPOURS WILL BE POSSIBLE.

SUNDAY... COLD FRONT SLOWLY MOVES THROUGH OUR REGION DURING SUNDAY.
EXPECTING SHOWERS TO CROSS OUR AREA DURING THE DAY...LOWER CHANCE
FOR THUNDERSTORMS. THE FRONT MAY REACH THE SOUTH COAST BY SUNDAY
NIGHT...BUT THERE IS SOME UNCERTAINTY AS TO WHETHER THE FRONT HANGS
UP IN OUR AREA FOR A PERIOD OF TIME. AT THIS TIME WILL CONTINUE WITH
HIGH CHANCE TO LIKELY POPS ON SUNDAY...THEN CHANCE POPS THRU SUNDAY
NIGHT.

MONDAY AND TUESDAY...THERE CONTINUES TO BE UNCERTAINTY ON HOW FAR
SOUTH THE FRONT TRACKS EVEN INTO THIS TIMEFRAME...WHETHER IT STALLS
NEAR THE SOUTH COAST OR FURTHER OFFSHORE. THIS WILL AFFECT OUR
CHANCES FOR SHOWERS. 00Z ECMWF WAS LEAST PROGRESSIVE WITH THE
FRONT...BUT THE 12Z ECMWF IS MORE PROGRESSIVE...NUDGING THE FRONT
SOUTH OF OUR AREA FOR MONDAY EVENING. 12Z GFS HAS OUR AREA MAINLY
DRY ON MONDAY. AT THIS TIME WILL CONTINUE WITH SLIGHT CHANCE TO
CHANCE POPS FOR MONDAY...AND TUESDAY GOING MAINLY DRY...WITH THE
HIGHEST POPS ALONG SOUTH COASTAL LOCALES. THUNDER LOOKS LESS
PROBABLE FOR THIS TIMEFRAME.

WEDNESDAY...MODELS ARE SHOWING SURFACE HIGH PRESSURE AND UPPER LEVEL
RIDGING BRINGING MAINLY DRY CONDITIONS TO OUR AREA.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...

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

THIS EVENING...LOW TO MODERATE CONFIDENCE. MIX OF VFR AND MVFR
CONDITIONS FOR THIS EVENING...WITH THE LOWER CIGS/VSBYS OVER THE
INTERIOR IN SCATTERED SHOWERS/ISOLATED THUNDERSTORMS...AND MVFR
CIGS SOUTH COASTAL MA AND RI IN STRATUS.

TONIGHT...LOW CLOUDS SHOULD ADVANCE FURTHER NORTH TONIGHT..BUT HOW
FAR NORTH THE LOW CLOUDS GET AND THEIR EXTENT REMAINS UNCERTAIN.
CIGS SHOULD BECOMING MAINLY MVFR...EXCEPT IFR SOUTH COASTAL MA
AND RI. WINDS PROBABLY DO NOT COMPLETELY DECOUPLE OVERNIGHT IN
MOST LOCATIONS...SO EXTENT OF FOG MAY BE LIMITED BUT SOME STILL
POSSIBLE ESPECIALLY ALONG AREAS OF THE SOUTH COAST/CAPE/ISLANDS.

THURSDAY...MODERATE CONFIDENCE. ANY LOWER CLOUDS AND FOG PATCHES
SHOULD BURN OFF BY LATE MORNING...EXCEPT FOR THE SOUTH
COAST/CAPE/ISLANDS WHERE MAY HANG TOUGH THROUGH THE AFTERNOON.
OTHERWISE...VFR BUT A COLD FRONT/PRE-FRONTAL TROUGH MAY BRING A
FEW STRONG THUNDERSTORMS DURING THE AFTERNOON RESULTING IN BRIEFLY
LOWER CONDITIONS.

KBOS TERMINAL...CONFIDENCE IN TAF DETERIORATES LATE THIS EVENING
AND OVERNIGHT.  VFR INTO THIS EVENING.  LOW CONFIDENCE IF IFR OR LOW
END MVFR CIGS CAN MAKE IT AS FAR NORTH AS THE BOS TERMINAL.

KBDL TERMINAL...LOW CONFIDENCE IN TAF. AN AREA OF
SHOWERS/THUNDERSTORMS CROSSING THRU BDL THRU 02Z OR SO WILL
PRODUCE VARIABLE CIGS/VSBYS. OTHERWISE...IMPROVEMENT TO VFR IS
PROBABLE LATE THIS EVENING...UNTIL LOWER CIGS MAY INVADE DURING THE
OVERNIGHT HOURS.

OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...MODERATE CONFIDENCE.

FRIDAY...VFR. MAY SEE LOCAL MVFR-IFR CONDITIONS EARLY MORNING ALONG
S COAST IN PATCHY FOG...THEN MAY LOWER AGAIN LATE FRI NIGHT TO MVFR-
IFR.

SATURDAY...PATCHY EARLY MORNING FOG WITH MVFR-IFR CONDITIONS... WILL
IMPROVE. SCT SHRA/TSRA SAT AFTERNOON THROUGH SAT NIGHT... WITH LOCAL
MVFR-IFR CONDITIONS.

SUNDAY...SCT SHOWERS LINGER WITH ISOLD TSTMS POSSIBLE DURING THE
DAY. MAY SEE BRIEF MVFR CONDITIONS.

MONDAY...CONDITIONS MAINLY VFR...EXCEPT MVFR WITH SCT SHOWERS SOUTH
COASTAL MA/RI.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /TONIGHT AND THURSDAY/...

TONIGHT...MODERATE TO HIGH CONFIDENCE.  NEAR SHORE SMALL CRAFT WIND
GUSTS DIMINISH AS THE EVENING PROGRESSES. HOWEVER...SCA CONTINUE
FOR THE OUTER- WATERS OVERNIGHT FOR MARGINAL 5 FOOT SEAS. AREAS OF
FOG MAY DEVELOP OVERNIGHT...BUT WINDS MAY BE A BIT TOO STRONG FOR
WIDESPREAD DENSE FOG.

THURSDAY...MODERATE TO HIGH CONFIDENCE.  ANOTHER ROUND OF NEAR SHORE
SOUTHWEST WIND GUSTS OF 25 KNOTS EXPECTED THURSDAY AFTERNOON.  LATER
SHIFTS WILL LIKELY HAVE TO HOIST MORE SMALL CRAFT ADVISORIES TO
COVER THIS POTENTIAL.  IN ADDITION...A FEW STRONG THUNDERSTORMS WITH
GUSTY WINDS AND HAIL ARE POSSIBLE LATE THURSDAY AFTERNOON AND
EVENING.

OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...MODERATE CONFIDENCE.

FRIDAY...LIGHT N-NE WINDS BECOME E DURING THE DAY...THEN SHIFT TO S-
SW FRI NIGHT. EXPECT WINDS AND SEAS BELOW SMALL CRAFT CRITERIA.

SATURDAY-SUNDAY...SW WINDS MAY BRIEFLY GUST TO 25 KT DURING SAT ON
THE EASTERN WATERS...AS A COLD FRONT APPROACHES THE WATERS.
OTHERWISE...EXPECTING GUSTS UP TO 20 KT. SEAS BUILD AGAIN TO AROUND
5 FT ACROSS THE OUTER WATERS.

MONDAY...COLD FRONT MAY LINGER NEAR THE WATERS DURING THIS
TIMEFRAME...WITH SEAS UP TO 5 FEET AND GUSTS TO 20 KT.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR ANZ250-
     254>256.

&&

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


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