Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 250210
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1010 PM EDT THU JUL 24 2014

.SYNOPSIS...
HIGH PRESSURE WILL BRING DRY AND BEAUTIFUL WEATHER INTO THE FIRST
PART OF THE WEEKEND.  SHOWERS AND THUNDERSTORMS POSSIBLE LATE THIS
WEEKEND INTO EARLY NEXT WEEK WITH AN APPROACHING FRONTAL SYSTEM.
THE COLD FRONT MOVES OFFSHORE TUESDAY WITH HIGH PRESSURE BUILDING IN
BEHIND.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
1005 PM UPDATE...EARLIER THIS EVENING THERE WERE TWO RENEGADE
SHOWERS...ONE NEAR LAWRENCE MA AND ANOTHER NEAR HOPKINTON RI.
BOTH OF THESE HAVE DISSIPATED. SOME PATCHY LOW CLOUDS REMAIN OVER
RI AND SOUTHEAST MA. OTHERWISE JUST SOME HIGH CLOUDINESS WAS
MOVING THROUGH SOUTHERN NEW ENGLAND...FROM THE NORTHERN FRINGES OF
A CONVECTIVE CLUSTER OVER THE VIRGINIA TIDEWATER REGION. THE
REMAINDER OF THE FORECAST WAS ON TRACK.

PREVIOUS DISCUSSION...

DRIER AIR WILL WORK IN FROM THE NORTHWEST ALLOWING FOR SKIES TO
BECOME MAINLY CLEAR TONIGHT. THIS WILL COMBINED WITH DIMINISHING
WINDS RESULTING IN A GOOD NIGHT OF RADIATIONAL COOLING. LOW TEMPS
WILL MAINLY BE IN THE 50S...TO THE LOWER 60S IN THE URBAN HEAT
ISLAND OF BOSTON. WE MAY EVEN SEE A FEW UPPER 40S IN THE NORMALLY
COOLEST OUTLYING LOCATIONS OF NORTHWEST MA/SOUTHWEST NH. QUITE A
COMFORTABLE NIGHT FOR LATE JULY STANDARDS.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
***BEAUTIFUL WEATHER FRIDAY WITH SUNNY SKIES/WARM AFTERNOON TEMPS
  AND LOW HUMIDITY***

FRIDAY...

AFTER A DRY RELATIVELY COOL START...PLENTY OF JULY SUNSHINE SHOULD
ALLOW MOST HIGHS SATURDAY AFTERNOON TO TOP OUT IN THE LOWER TO
MIDDLE 80S IN MOST LOCALES.  A WEAK PRESSURE GRADIENT WILL ALLOW FOR
SEA BREEZES TO DEVELOP ON THE IMMEDIATE COAST...RESULTING IN HIGH
TEMPS A FEW DEGREES COOLER IN THOSE LOCATIONS.  THE BIG STORY WILL
BE THE LOW HUMIDITY MAKING FOR AN EXCELLENT DAY FOR OUTDOOR
ACTIVITIES.

FRIDAY NIGHT...

ANOTHER NICE/DRY NIGHT IN STORE FOR SOUTHERN NEW ENGLAND.  MAY SEE A
BIT OF HIGH CLOUDINESS MOVE INTO THE REGION LATE...BUT THAT IS ABOUT
IT.  LOW TEMPS SHOULD BOTTOM OUT MAINLY IN THE 50S...TO THE LOWER
60S.  MAY SEE A TOUCH OF PATCHY GROUND FOG DEVELOP LATE IN THE
TYPICALLY PRONE LOCATIONS...BUT NOTHING WIDESPREAD.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
* SHOWERS AND THUNDERSTORMS POSSIBLE OVER THE WEEKEND AND INTO EARLY
  NEXT WEEK
* HIGH PRESSURE BUILDS IN BEHIND COLD FRONT WED AND THU

ON A SYNOPTIC LEVEL...THE MODELS INCLUDING THE ECMWF ENSEMBLE AND
GEFS ARE IN DECENT AGREEMENT. HOWEVER...THERE ARE OF COURSE MANY
DISCREPANCIES WHEN IT COMES TO THE MESOSCALE DETAILS.  THE OVERALL
PATTERN HAS AN ANOMALOUSLY STRONG PERSISTENT UPPER TROUGH OVER THE
GREAT LAKES WITH PERSISTENT RIDGING OVER THE WESTERN CONUS.  THIS
BRINGS SOME TIMING CONCERNS AS THE PERSISTENT TROUGH IS LIKELY TO
SLOW THE TRAVEL OF A COLD FRONT EXPECTED TO MOVE ACROSS THE REGION
LATE SUNDAY THROUGH TUESDAY.  THE MAIN CONCERN FOR THIS PERIOD OF
THE FORECAST WILL BE THE SATURDAY TO MONDAY TIME FRAME WHEN SHOWERS
AND THUNDERSTORMS ARE LIKELY.  THERE IS A POTENTIAL FOR SEVERE
THUNDERSTORMS SOMETIME DURING THIS TIME FRAME BUT THERE IS QUITE A
BIT OF UNCERTAINTY WHEN IT COMES TO THE DETAILS AND TIMING OF THIS
POTENTIAL.  AFTER THE COLD FRONT MOVES OFFSHORE TUESDAY...EXPECT
HIGH PRESSURE TO BUILD IN ACROSS SOUTHERN NEW ENGLAND.

SATURDAY THROUGH MONDAY...LOW PRESSURE MOVES THROUGH SOUTHEASTERN
CANADA EVENTUALLY...SLOWLY...PULLING A COLD FRONT THROUGH SOUTHERN
NEW ENGLAND.  CONCURRENTLY...A SERIES OF SHORTWAVES WILL ROTATE
AROUND THE PERSISTENT UPPER TROUGH OVER THE GREAT LAKES.
INCREASINGLY WARMER AND MORE HUMID AIR WILL MOVE INTO THE REGION ON
SOUTHWESTERLY WINDS.  ALL OF THIS WILL COME TOGETHER RESULTING IN A
RATHER UNSTABLE ENVIRONMENT WITH MULTIPLE POTENTIAL TRIGGERS FOR
SHOWERS AND THUNDERSTORMS.

MUCH OF SATURDAY LOOKS TO BE DRY WITH SHOWERS AND THUNDERSTORMS
LIKELY NOT DEVELOPING UNTIL SATURDAY NIGHT.  THEN QUITE A BIT OF
INSTABILITY ACROSS THE REGION SATURDAY NIGHT INTO SUNDAY WITH SB
CAPES FORECAST TO BE OVER 1000 J/KG AND POSSIBLY OVER 2000 J/KG ON
SUNDAY.  IN ADDITION...EXPECTING 30 TO 40 KTS OF 0 TO 6 KM BULK
SHEAR DURING THIS TIME.  DEPENDING ON WHEN ALL OF THIS COMES
TOGETHER AND WHICH MODEL HAS THE DETAILS RIGHT...WE COULD BE LOOKING
AT SOME OF THESE THUNDERSTORMS BECOMING SEVERE.  SUNDAY IS THE REAL
QUESTION MARK AS WHETHER THERE ARE STORMS OR NOT WILL DEPEND ON HOW
MUCH OCCURS SATURDAY NIGHT AND HOW WORKED OVER THE ATMOSPHERE
BECOMES.  EXPECT STORMS TO OCCUR AGAIN MONDAY AS THE COLD FRONT
FINALLY STARTS TO MOVE INTO SOUTHERN NEW ENGLAND.

TUESDAY THROUGH THURSDAY...THE COLD FRONT FINALLY MOVES OFFSHORE ON
TUESDAY.  THERE COULD BE A FEW LINGERING SHOWERS ON THE CAPE BEFORE
IT PUSHES THE REST OF THE WAY OFFSHORE.  HIGH PRESSURE THEN BUILDS
IN OVER SOUTHERN NEW ENGLAND WEDNESDAY AND SLIDES OFFSHORE ON
THURSDAY.  OF COURSE...ALL OF THIS WILL BE DEPENDENT ON THE SPEED OF
THE COLD FRONT.  IF IT SLOWS DOWN ANYMORE...THEN SHOWERS AND STORMS
COULD LINGER INTO TUESDAY FOR MORE OF THE AREA.

&&

.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 NIGHT/...HIGH CONFIDENCE.

TONIGHT THROUGH FRIDAY NIGHT...

VFR CONDITIONS RIGHT THROUGH FRIDAY NIGHT OTHER THAN VERY
LOCALIZED LATE NIGHT/EARLY MORNING FOG.

KBOS TAF...HIGH CONFIDENCE. SEA BREEZE RETURNS BY FRIDAY AFTERNOON.

KBDL TAF...HIGH CONFIDENCE.

OUTLOOK...SATURDAY THROUGH TUESDAY...

SATURDAY THROUGH MONDAY...MODERATE CONFIDENCE. MAINLY VFR. PERIODS
OF MVFR/IFR LIKELY IN SHRA/TSRA.

TUESDAY...MODERATE CONFIDENCE.  VFR. LOW PROBABILITY OF MVFR
CONDITIONS ON THE CAPE AND ISLANDS.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

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

EXCELLENT BOATING WEATHER THROUGH FRIDAY NIGHT WITH WEAK PRESSURE
GRADIENT KEEPING WINDS/SEAS WELL BELOW SCA THRESHOLDS.  VISIBILITIES
SHOULD BE EXCELLENT MOST OF THE TIME.

OUTLOOK...SATURDAY THROUGH TUESDAY...

MODERATE CONFIDENCE.  SOUTHWESTERLY WINDS AND SEAS INCREASE
GRADUALLY AS A COLD FRONT SLOWLY APPROACHES THE WATERS.  SHOWERS AND
THUNDERSTORMS ARE POSSIBLE SATURDAY NIGHT THROUGH TUESDAY OVER THE
WATERS.  SMALL CRAFT ADVISORIES WILL BE NECESSARY SATURDAY NIGHT
THROUGH TUESDAY FOR SEAS AND SUNDAY FOR WINDS GUSTING TO AROUND 25
KTS.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...FRANK/RLG
NEAR TERM...FRANK/FIELD
SHORT TERM...FRANK
LONG TERM...RLG
AVIATION...FRANK/RLG/FIELD
MARINE...FRANK/RLG/FIELD



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