Special Weather Statement, NWS Boston/Norton, MA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
326 PM EDT WED AUG 15 2012

.SYNOPSIS...
WEAK LOW PRESSURE AND A FRONTAL SYSTEM WILL BRING SCATTERED SHOWERS
AND THUNDERSTORMS AS IT MOVES ACROSS SOUTHERN NEW ENGLAND
TONIGHT...EXITING THE COAST THU AFTERNOON.  AFTER A BRIEF DRY
SPELL...ANOTHER COLD FRONT MAY BRING ADDITIONAL SCATTERED SHOWERS
AND THUNDERSTORMS LATE FRI INTO THE WEEKEND. HIGH PRESSURE SHOULD
BRING DRY AND COOLER WEATHER TO THE REGION EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WEAK SHEAR ENVIRONMENT AND MARGINAL MID LEVEL LAPSE RATES ARE
LIMITING CONVECTION THIS AFTERNOON...WITH JUST SCT SHOWERS
DEVELOPING ACROSS INTERIOR NEW ENG.  HOWEVER...AS MID LEVEL
SHORTWAVE OVER W PA/WV APPROACHES TOWARD 00Z...LAPSE RATES AND DEEP
LAYER SHEAR IS FORECAST TO INCREASE WHICH SHOULD ALLOW STORMS TO
BECOME BETTER ORGANIZED WITH INCREASING COVERAGE. WE WILL CONTINUE
WITH LIKELY POPS THIS EVENING.  A SECOND SHORTWAVE FROM THE GT LAKES
MOVES INTO NEW ENG LATE TONIGHT WHICH WILL HELP TO SUSTAIN
CONVECTION ACROSS E NEW ENG OVERNIGHT THROUGH COOLING ALOFT AND
STEEPENING MID LEVEL LAPSE RATES.  500 MB TEMPS DECREASE TO -12 TO
14C BY 12Z AND MODELS MAINTAIN SOME SFC INSTABILITY THROUGH THE
NIGHT...WITH AN INCREASE NOTED OVER THE COASTAL PLAIN TOWARD 12Z
ASSOCD WITH THE SHORTWAVE AND COOLING ALOFT.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
MID LEVEL TROF WILL BE OVER NEW ENG AT 12Z THEN IT LIFTS NE DURING
THE DAY.  COLD POOL ALOFT WILL HELP TO DESTABILIZE ATMOSPHERE AS SFC
HEATING TAKES PLACE...WITH CAPES INCREASING TO 1000-1500 J/KG.
EXPECT SCT SHOWERS/TSTMS TO REDEVELOP BY LATE MORNING...ESPECIALLY
FROM S NH THROUGH E MA WHERE BEST INSTABILITY IS LOCATED...THEN
ACTIVITY DECREASING TOWARD MID/LATE AFTERNOON AS THE COLD POOL LIFTS
OUT WITH WARMING TEMPS ALOFT.  WE WILL HAVE CHC POPS CENTRAL AND
EASTERN NEW ENG WITH POPS DECREASING TOWARD CT VALLEY WHERE IT
SHOULD REMAIN DRY.  WE HAVE A MODERATELY SHEARED ENVIRONMENT
THURSDAY WITH 0-6KM SHEAR 30-35 KT SO POTENTIAL EXISTS FOR SOME
STORMS TO BECOME ORGANIZED WITH LOW PROB OF A FEW SEVERE STORMS.
HAIL WOULD BE THE PRIMARY THREAT GIVEN COLD TEMPS ALOFT.  850 MB
TEMPS 14-15C TRANSLATES TO MAXES IN THE LOW TO MID 80S...COOLER
HIGHER TERRAIN. MORE WEIGHT GIVEN TO COOLER BIAS CORRECTED
GUIDANCE AS TRADITIONAL MOS LOOKS A BIT TOO WARM.

&&

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

  * COLD FRONT BRINGS MORE SHOWERS/THUNDERSTORMS FRI INTO WEEKEND
  * HIGH PRESSURE/DRY WEATHER RETURNS EARLY NEXT WEEK

OVERVIEW...
MODELS ARE IN BETTER AGREEMENT ON THE SYNOPTIC PATTERN OVER THE LONG
TERM.  OVERALL PATTERN HAS A WEAK UPPER RIDGE MOVING OFFSHORE
THURSDAY NIGHT.  LOW PRESSURE MOVES THROUGH SOUTHEASTERN CANADA
BRINGING A COLD FRONT THROUGH SOUTHERN NEW ENGLAND FRIDAY NIGHT INTO
SATURDAY.  THIS WILL LIKELY BRING SHOWERS AND THUNDERSTORMS TO THE
REGION.  THEN HIGH PRESSURE BUILDS INTO THE REGION EARLY NEXT WEEK
BRINGING DRY WEATHER.

THURSDAY NIGHT AND FRIDAY...WEAK MID LEVEL RIDGE MOVES OFFSHORE
SOUTHERN NEW ENGLAND.  DRY WEATHER EXPECTED WITH GRADUALLY CLEARING
SKIES.  TEMPERATURES SHOULD BE RIGHT AROUND NORMAL.

FRIDAY NIGHT THROUGH SUNDAY...SLOW MOVING COLD FRONT MOVES THROUGH
SOUTHERN NEW ENGLAND BRINGING ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS.  SOUTHWESTERLY FLOW INTO THE REGION WILL BRING
TROPICAL MOISTURE INTO THE AREA WITH PWATS 1.75 INCHES TO 2 INCHES
/1.5 TO 2 TIMES NORMAL FOR AUGUST/.  THIS WILL RESULT IN HEAVY
DOWNPOURS WITH ANY SHOWERS AND THUNDERSTORMS THAT DEVELOP.  WILL
KEEP CHANCE POPS IN FOR THIS TIME PERIOD WITH UNCERTAINTY IN TIMING
AND COVERAGE.  TEMPERATURES SHOULD BE RIGHT AROUND OR A COUPLE OF
DEGREES BELOW NORMAL.

MONDAY THROUGH WEDNESDAY...HIGH PRESSURE BUILDS INTO SOUTHERN NEW
ENGLAND BEHIND THE COLD FRONT.  THIS WILL RESULT IN SEASONABLE...DRY
WEATHER.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
  LOW...LESS THAN 30 PERCENT
  MODERATE...30 PERCENT TO 60 PERCENT
  HIGH...GREATER THAN 60 PERCENT

OVERVIEW...MODERATE CONFIDENCE. SCT SHOWERS/TSTMS TO INCREASE IN
COVERAGE ACROSS THE INTERIOR THIS AFTERNOON...THEN MOVING EAST
ACROSS SNE TONIGHT. A PERIOD OF MVFR CONDITIONS EXPECTED IN ANY
STORMS AND PATCHY LATE NIGHT MVFR/IFR FOG POSSIBLE. MAINLY VFR
THU...BUT SCT SHOWERS/TSTMS EXPECTED TO REDEVELOP ESPECIALLY FROM
S NH THROUGH E MA.

KBOS TERMINAL...
MODERATE CONFIDENCE. NOT REALLY A TRUE SEABREEZE THIS AFTERNOON AS
LOW LEVEL FLOW DRIVING SE WINDS. SCT TSTMS POSSIBLE AFTER 20Z AND
MAY LINGER INTO TONIGHT.

KBDL TERMINAL...
MODERATE CONFIDENCE. SCT TSTMS LIKELY THIS AFTERNOON AND POSSIBLY
LINGERING INTO THIS EVENING.

OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...

THU NIGHT THRU MOST OF FRIDAY...HIGH CONFIDENCE OF VFR.
LATE FRIDAY THRU SATURDAY EVENING...MODERATE CONFIDENCE. MOSTLY VFR
BUT AREAS OF MVFR AND EVEN LOCALIZED IFR IN SCT SHOWERS AND TSTMS.
SUNDAY...LOW TO MODERATE CONFIDENCE. VFR EXPECTED W AND NW OF ORH
WHILE POTENTIAL FOR AREAS OF MVFR IN SHOWERS AND ISOLATED EMBEDDED
TSTMS E AND SE OF ORH.

&&

.MARINE...
HIGH CONFIDENCE THROUGH THURSDAY.

LIGHT WINDS LESS THAN 20 KT AND SEAS WELL BELOW 5 FT EXPECTED.  SCT
TSTMS POSSIBLE TONIGHT AND AGAIN DURING THU.

OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...

LIGHT WINDS GENERALLY LESS THAN 20 KT AND SEAS BELOW 5 FT EXPECTED
THRU THE PERIOD. THERE WILL BE A RISK OF TSTMS FROM TIME TO TIME
OVER THE WEEKEND...BEFORE TURNING DRY FOR THE FIRST PART OF NEXT
WEEK. PATCHY FOG POSSIBLE FRI AND SAT NIGHTS.

&&

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

&&

SYNOPSIS...KJC/RLG
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...RLG
AVIATION...KJC/RLG
MARINE...KJC/RLG

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TAUNTON MA
330 PM EDT WED AUG 15 2012

CTZ002>004-MAZ002>024-026-NHZ011-012-015-RIZ001>008-161930-
HARTFORD CT-TOLLAND CT-WINDHAM CT-WESTERN FRANKLIN MA-
EASTERN FRANKLIN MA-NORTHERN WORCESTER MA-CENTRAL MIDDLESEX MA-
WESTERN ESSEX MA-EASTERN ESSEX MA-WESTERN HAMPSHIRE MA-
WESTERN HAMPDEN MA-EASTERN HAMPSHIRE MA-EASTERN HAMPDEN MA-
SOUTHERN WORCESTER MA-WESTERN NORFOLK MA-SOUTHEAST MIDDLESEX MA-
SUFFOLK MA-EASTERN NORFOLK MA-NORTHERN BRISTOL MA-
WESTERN PLYMOUTH MA-EASTERN PLYMOUTH MA-SOUTHERN BRISTOL MA-
SOUTHERN PLYMOUTH MA-BARNSTABLE MA-DUKES MA-NANTUCKET MA-
NORTHERN MIDDLESEX MA-CHESHIRE NH-EASTERN HILLSBOROUGH NH-
WESTERN AND CENTRAL HILLSBOROUGH NH-NORTHWEST PROVIDENCE RI-
SOUTHEAST PROVIDENCE RI-WESTERN KENT RI-EASTERN KENT RI-BRISTOL RI-
WASHINGTON RI-NEWPORT RI-BLOCK ISLAND RI-
330 PM EDT WED AUG 15 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHERN CONNECTICUT...
CENTRAL MASSACHUSETTS...EASTERN MASSACHUSETTS...NORTHEASTERN
MASSACHUSETTS...SOUTHEASTERN MASSACHUSETTS...WESTERN MASSACHUSETTS...
SOUTHERN NEW HAMPSHIRE...NORTHERN RHODE ISLAND AND SOUTHERN RHODE
ISLAND.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

ISOLATED THUNDERSTORMS THIS AFTERNOON AND TONIGHT COULD BE STRONG
WITH THE POTENTIAL FOR STRONG WINDS...HAIL...AND LOCALIZED FLASH
FLOODING.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

THE POTENTIAL EXISTS FOR STRONG THUNDERSTORMS WITH HAIL IN
SOUTHEAST NH...EASTERN MA...AND RHODE ISLAND THU MORNING AND EARLY
AFTERNOON.

A FEW THUNDERSTORMS LATE IN THE AFTERNOON AND EVENING ON BOTH
FRIDAY AND SATURDAY COULD BE STRONG TO SEVERE...WITH DAMAGING
WINDS...LARGE HAIL...AND LOCALIZED HEAVY DOWNPOURS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

ANZ230>237-250-251-254>256-161930-
BOSTON HARBOR-CAPE COD BAY-NANTUCKET SOUND-VINEYARD SOUND-
BUZZARDS BAY-RHODE ISLAND SOUND-NARRAGANSETT BAY-BLOCK ISLAND SOUND-
COASTAL WATERS EAST OF IPSWICH BAY AND THE STELLWAGEN BANK NATIONAL
MARINE SANCTUARY-MASSACHUSETTS BAY AND IPSWICH BAY-
COASTAL WATERS FROM PROVINCETOWN MA TO CHATHAM MA TO NANTUCKET MA
OUT 20 NM-
COASTAL WATERS EXTENDING OUT TO 25 NM SOUTH OF MARTHAS VINEYARD AND
NANTUCKET-
COASTAL WATERS FROM MONTAUK NY TO MARTHAS VINEYARD EXTENDING OUT TO
20 NM SOUTH OF BLOCK ISLAND-
330 PM EDT WED AUG 15 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MASSACHUSETTS COASTAL WATERS
AND RHODE ISLAND COASTAL WATERS.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

SCATTERED STRONG THUNDERSTORMS TODAY AND TONIGHT COULD PRODUCE
LOCALLY HEAVY DOWNPOURS AND LOCALLY HIGHER WINDS AND SEAS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

THE POTENTIAL EXISTS FOR STRONG THUNDERSTORMS WITH HAIL ACROSS THE
WATERS THU MORNING AND EARLY AFTERNOON.

A FEW THUNDERSTORMS LATE IN THE AFTERNOON AND EVENING ON BOTH
FRIDAY AND SATURDAY COULD BE STRONG TO SEVERE...WITH DAMAGING
WINDS...LARGE HAIL...AND LOCALIZED HEAVY DOWNPOURS..

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TAUNTON MA
224 PM EDT WED AUG 15 2012

MAZ002-003-151915-
EASTERN FRANKLIN MA-WESTERN FRANKLIN MA-
224 PM EDT WED AUG 15 2012

...THUNDERSTORM WITH TORRENTIAL RAINFALL IN NORTHWEST
MASSACHUSETTS...

AT 220 PM...A SLOW MOVING THUNDERSTORM PRODUCING RAINFALL RATES OF 1
INCH PER HOUR WAS LOCATED NEAR CONWAY IN FRANKLIN COUNTY. THE STORM
WAS DRIFTING NORTHEAST AT 5 MPH.

THIS STORM WILL PRODUCE MINOR FLOODING AS IT AFFECTS
CONWAY...DEERFIELD...GREENFIELD AND MONTAGUE THROUGH 330 PM.

MINOR STREET FLOODING AND PONDING OF WATER IN LOW LYING AREAS SUCH
AS UNDERPASSES CAN BE EXPECTED. DO NOT DRIVE THROUGH FLOODED ROADS.

&&

LAT...LON 4261 7253 4253 7251 4248 7270 4256 7274

JWD

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TAUNTON MA
539 PM EDT WED AUG 15 2012

CTZ003-MAZ008>011-152245-
EASTERN HAMPDEN MA-EASTERN HAMPSHIRE MA-TOLLAND CT-WESTERN HAMPDEN
MA-WESTERN HAMPSHIRE MA-
539 PM EDT WED AUG 15 2012

AT 537 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM CAPABLE OF PRODUCING WIND GUSTS TO 40 MPH AND
PENNY SIZED HAIL 2 MILES NORTHEAST OF MONTGOMERY...OR ABOUT 9 MILES
SOUTHWEST OF NORTHAMPTON...MOVING SOUTHEAST AT 15 MPH.

* SOME LOCATIONS AFFECTED INCLUDE...SOUTHAMPTON...EASTHAMPTON...
  WESTFIELD...SOUTHWICK...HOLYOKE...WEST SPRINGFIELD...SOUTH
  HADLEY...GRANBY...CHICOPEE...AGAWAM...WILBRAHAM...SPRINGFIELD...
  LUDLOW...LONGMEADOW...EAST LONGMEADOW AND BELCHERTOWN.

FOR YOUR SAFETY...GET INSIDE WHEN THIS STORM APPROACHES. WINDS MAY BE
STRONG ENOUGH TO BRING DOWN SMALL BRANCHES. MINOR STREET FLOODING AND
PONDING OF WATER IN POOR DRAINAGE AREAS IS ALSO POSSIBLE.

&&

LAT...LON 4217 7285 4224 7283 4234 7283 4226 7231
      4203 7244 4204 7276 4210 7284 4213 7284

DUNTEN