Severe Thunderstorm Warning 132, NWS Boston/Norton, MA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
448 PM EDT MON AUG 13 2007

.SYNOPSIS...
A COLD FRONT WILL CROSS SOUTHERN NEW ENGLAND TONIGHT. HIGH PRESSURE
WILL BUILD OVER SOUTHERN NEW ENGLAND TUE. ANOTHER WEAK COLD FRONT
WILL CROSS THE REGION WED FOLLOWED BY A STRONGER COLD FRONT LATE THU
AND EARLY FRI. DRY HIGH PRESSURE WILL BUILD INTO THE REGION LATE FRI
THROUGH SUN.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A BROKEN LINE OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A COLD
FRONT WAS CROSSING CENTRAL AND EASTERN MASSACHUSETTS THIS EVENING.
THE CONVECTION WAS INTERACTING WITH MODERATE LOW LEVEL INSTABILITY
AHEAD OF IT...WITH SURFACE BASED CAPES BETWEEN 1500 TO 2000 J/KG.
THE SHOWERS AND THUNDERSTORMS WILL BEGIN TO WEAKEN TOWARDS SUNSET
DUE TO THE LOSS OF DAYTIME HEATING. USED ENHANCED WORDING THROUGH
00Z WITH GUSTY WINDS AND SMALL HAIL POSSIBLE. OTHERWISE DRIER
DEWPOINT AIR WILL BEGIN TO INFILTRATE THE REGION OVERNIGHT. MOSTLY
CLEAR SKIES AND DECOUPLING WINDS WILL ALLOW FOG PATCHES TO FORM.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE COVERS THE REGION WITH MOSTLY CLEAR SKIES AND JUST A
FEW FAIR WEATHER CUMULUS CLOUDS. 850 MILLIBAR TEMPERATURES BETWEEN
+7 AND +9 CELSIUS AND BOUNDARY MIXING UP THE DRY ADIABAT NEAR 800
MILLIBARS SUPPORTS HIGHS IN THE MID 70S TO SOME LOWER 80S AWAY FROM
THE COAST. USED THE WARMER MAVMOS GUIDANCE TEMPS WHICH APPEARED MORE
REASONABLE...EXCEPT USED THE NAM/WRF WIND VELOCITIES.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
WARM AIR ADVECTION PATTER TUESDAY NIGHT...BUT MOISTURE IN THE COLUMN
LOOKS A BIT TOO MEAGER FOR ANY PRECIPITATION. ON WEDNESDAY...COLD
FRONT WILL TRAVERSE THE CWA. THE FROPA LOOKS TO BE SLOW ENOUGH SO
THAT AT LEAST THE SOUTHEASTERN HALF OF THE CWA WILL STILL BE IN THE
PREFRONTAL AIRMASS DURING PEAK HEATING. THEREFORE...HAVE FORECASTED
LOW CHANCE POPS FOR SHOWERS AND THUNDERSTORMS. THE CHANCE WILL BE A
BIT BETTER IF WE CAN SOMEHOW MUSTER UP A DEEPER LOW LEVEL MOISTURE
PROFILE. STAYED CLOSE TO MAV GUIDANCE FOR MAXES.

SOME SHOWERS AND/OR ISOLD TSTMS SHOULD BE LINGERING ACROSS THE SOUTH
COAST DURING WEDNESDAY EVENING BEFORE DISSIPATING LATE. COLD FRONT
QUICKLY MOVES BACK NORTH AS A WARM FRONT SOMETIME THURSDAY AS SHORT
WAVE APPROACHES AND PUSHES A COLD FRONT ACRS THE REGION SOMETIME
FRIDAY. WILL THEREFORE GO WITH CHANCE POPS FOR SHOWERS AND TSTMS
DURING THIS TIMEFRAME. WENT WITH THE WARMER MAV GUIDANCE FOR MAXES
ON THURSDAY.

FAIR WEATHER FOR FRIDAY THROUGH THE WEEKEND AS A POTENTIALLY SHARP
CANADIAN AIRMASS MOVES INTO NEW ENGLAND IN THE WAKE OF THE COLD
FRONT FRIDAY. THIS SHOULD SET US UP WITH SOME COOL...DRY...AND
SUNNY/CLEAR WX FOR THIS TIMEFRAME. THIS COULD END UP BEING THE MOST
STELLAR WEEKEND OF THE SUMMER IF CURRENT MODEL PROGS VERIFY. THE GFS
IS USUALLY TOO COLD WITH AIRMASSES AT THIS RANGE...BUT IN THE RARE
CHANCE THAT IT DOES THIS TIME...I COULD SEE LOWS AROUND 40 IN
PORTIONS OF SRN NH AND NWRN MASS SAT NIGHT. ARE THE SEASONS STARTING
TO CHANGE?

&&

.AVIATION /21Z MONDAY THROUGH SATURDAY/...
SCT SHRA/TSRA WILL BRING BRIEF IFR/MVFR VSBYS AND AN ABRUPT WINDSHIFT
TO THE NORTHWEST WITH GUSTS TO 35 KT POSSIBLE. MVFR VSBYS IN FOG
PATCHES POSSIBLE OVERNIGHT. SOME MECHANICAL WIND SHEAR POSSIBLE DUE
TO COOL AIR ADVECTION ACROSS THE LOW LYING TERMINALS KBAF-KBDL
OVERNIGHT. VFR CONDITIONS EXPECTED TUE WITH FEW050-060.

IN THE LONG TERM...NOT TOO MUCH TO SPEAK OF. WELL HAVE A COLD FRONT
CROSS SOUTHERN NEW ENGLAND ON WED WITH A CHANCE OF
SHOWERS/STORMS...AND ANOTHER POTENTIALLY STRONGER COLD FROPA FRIDAY.
OTHER THAN THAT...THERES NOT TOO MUCH THAT COULD BRING CIGS/VSBYS
DOWN LOWER THAN VFR IN THE LONG TERM...TUE NIGHT THRU FRI.

&&

.MARINE...
BRIEF WIND GUSTS AROUND 30 KT POSSIBLE THIS EVENING ACROSS THE
COASTAL WATERS IN WIDELY SCATTERED THUNDERSTORMS. OTHERWISE
BRIEF GUSTS AROUND 20 KT EXPECTED IN COOL AIR ADVECTION AROUND
06Z TONIGHT. LIGHT NORTH WINDS BECOMING LOCALLY ONSHORE TUE.
SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA
MAINLY 1 TO 3 FT.

IN THE LONG TERM TUE NIGHT THRU FRIDAY...NOTHING LOOKS LIKE ITLL
BREAK THE RELATIVE TRANQUILITY WEVE BEEN HAVING AS OF LATE. WELL
HAVE A COLD FRONT CROSS SOUTHERN NEW ENGLAND ON WED WITH A CHANCE OF
SHOWERS/STORMS. THE PRESSURE GRADIENT MAY TIGHTEN ENOUGH TO PRODUCE
SMALL CRAFT WINDS LATE WED MORNING INTO THE AFTERNOON HOURS. ANOTHER
FRONT LOOKS TO PASS ON FRIDAY. DEPENDING ON HOW COOL THE AIR IS
BEHIND THE FRONT...NORTHERLY SMALL CRAFT WINDS WILL BE POSSIBLE
LATER FRIDAY INTO EARLY SATURDAY.

&&

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

&&

SYNOPSIS...STRAUSS
NEAR TERM...STRAUSS
SHORT TERM...STRAUSS
LONG TERM...EKSTER
AVIATION...EKSTER/STRAUSS
MARINE...EKSTER/STRAUSS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TAUNTON MA
103 PM EDT MON AUG 13 2007

CTZ002>004-MAZ002>022-026-NHZ011-012-015-RIZ001>007-141715-
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-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-
103 PM EDT MON AUG 13 2007

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON. SOME WILL
BRING SMALL HAIL AND GUSTY WINDS TO 45 MPH WITH LOCALLY HEAVY
DOWNPOURS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

COLD FRONTAL PASSAGES WILL BE LIKELY WEDNESDAY AND FRIDAY. BOTH
FRONTAL PASSAGES MAY BE ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE NECESSARY THIS AFTERNOON. PLEASE SEND ANY
REPORTABLE CRITERIA TO THE NATIONAL WEATHER SERVICE.

ANZ230>237-250-254-255-270-MAZ023-024-RIZ008-141715-
BOSTON HARBOR-CAPE COD BAY-NANTUCKET SOUND-VINEYARD SOUND-
BUZZARDS BAY-RHODE ISLAND SOUND-NARRAGANSETT BAY-BLOCK ISLAND SOUND-
COASTAL WATERS FROM MERRIMACK RIVER MA OUT 25 NM TO PLYMOUTH MA OUT
40 NM...INCLUDING THE STELLWAGEN BANK NATIONAL MARINE SANCTUARY-
COASTAL WATERS FROM PROVINCETOWN MA TO CHATHAM MA TO NANTUCKET MA
OUT 20 NM-
COASTAL WATERS FROM MONTAUK NY TO BLOCK ISLAND RI TO MARTHAS
VINEYARD MA TO NANTUCKET MA SOUTHEAST TO 20 NM-
WATERS FROM MERRIMACK RIVER MA TO WATCH HILL RI FROM 25 TO 40 NM-
DUKES MA-NANTUCKET MA-BLOCK ISLAND RI-
103 PM EDT MON AUG 13 2007

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON. SOME WILL
BRING SMALL HAIL AND GUSTY WINDS TO 45 MPH WITH LOCALLY HEAVY
DOWNPOURS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

OLD FRONTAL PASSAGES WILL BE LIKELY WEDNESDAY AND FRIDAY. BOTH
FRONTAL PASSAGES MAY BE ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE NECESSARY THIS AFTERNOON. PLEASE SEND ANY
REPORTABLE CRITERIA TO THE NATIONAL WEATHER SERVICE.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TAUNTON MA
114 PM EDT MON AUG 13 2007

MAZ005-014-026-131745-
CENTRAL MIDDLESEX COUNTY MA-NORTHWEST MIDDLESEX COUNTY MA-SOUTHEAST
MIDDLESEX MA-
114 PM EDT MON AUG 13 2007

AT 109 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM WITH POSSIBLE SMALL HAIL OVER BOXBOROUGH MOVING
SOUTHEAST AT 15 MPH. THIS STORM ALSO CONTAINS VERY HEAVY RAIN WHICH
WILL IMPACT COMMUTERS WITH LOW VISIBILITIES AND PONDING OF WATER ON
ROADWAYS.

THE THUNDERSTORM WILL BE NEAR...MAYNARD BY 120 PM EDT...CONCORD BY
130 PM EDT...LINCOLN BY 140 PM EDT...WESTON AND WALTHAM BY 150 PM
EDT.

DUNHAM

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TAUNTON MA
349 PM EDT MON AUG 13 2007

MAZ004>007-012>015-132045-
CENTRAL MIDDLESEX COUNTY MA-EASTERN ESSEX MA-NORTHERN WORCESTER
MA-SOUTHEAST MIDDLESEX MA-SOUTHERN WORCESTER MA-SUFFOLK MA-WESTERN
ESSEX MA-WESTERN NORFOLK MA-
349 PM EDT MON AUG 13 2007

AT 341 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE
OF STRONG THUNDERSTORMS WITH THE POTENTIAL TO PRODUCE WIND GUSTS TO
40 MPH AND SMALL HAIL ALONG A LINE EXTENDING FROM 9 MILES SOUTH OF
NEWBURYPORT TO 5 MILES SOUTHWEST OF WORCESTER...MOVING SOUTHEAST AT
15 MPH. THESE STORMS ALSO CONTAIN VERY HEAVY RAIN THAT MAY CAUSE
LOCALIZED ROAD FLOODING

THUNDERSTORMS WILL BE NEAR...IPSWICH...WOBURN...WESTBOROUGH AND
WENHAM BY 400 PM EDT...ESSEX...WINCHESTER...WAYLAND AND WALTHAM BY
410 PM EDT...MANCHESTER AND WESTON BY 420 PM EDT.

DUNHAM

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TAUNTON MA
505 PM EDT MON AUG 13 2007

MAZ013-017>020-RIZ001-002-004-005-132200-
BRISTOL RI-EASTERN KENT RI-EASTERN PLYMOUTH MA-NORTHERN BRISTOL
MA-NORTHWEST PROVIDENCE RI-SOUTHEAST PROVIDENCE RI-SOUTHERN BRISTOL
MA-WESTERN NORFOLK MA-WESTERN PLYMOUTH MA-
505 PM EDT MON AUG 13 2007

AT 459 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE
OF STRONG THUNDERSTORMS WITH THE POTENTIAL TO PRODUCE WIND GUSTS TO
40 MPH AND SMALL HAIL ALONG A LINE EXTENDING FROM SHARON
MASSACHUSETTS TO 4 MILES NORTHEAST OF SCITUATE RHODE ISLAND MOVING
EAST AT 20 MPH. THESE STORMS ALSO CONTAIN VERY HEAVY RAIN.

THUNDERSTORMS WILL BE NEAR...NORTH PROVIDENCE...STOUGHTON...
PROVIDENCE AND PAWTUCKET BY 510 PM EDT...PROVIDENCE...NORTON...EASTON
AND BROCKTON BY 520 PM EDT...EAST PROVIDENCE AND SEEKONK BY 530 PM
EDT.

DUNHAM