Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 42, NWS Boston/Norton, MA

August 20, 2004Essex County, Middlesex County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Aug 20, 2004, 4:29 PM EDT for Essex County, Middlesex County, Massachusetts. It was in force for 46 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 20, 2004, 4:29 PM EDT (20:29 UTC)
Expired
Aug 20, 2004, 5:15 PM EDT
In force
46 min
Issued by
NWS Boston/Norton, MA
Area
Counties, with a storm outline in the text

Counties Essex County, MA, Middlesex County, MA

The radar

The Boston radar (KBOX), 76 km from the middle of the area, began a volume at 20:31 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 20, 1:05 PM EDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Chatham, MA (KCHH), launched 12:00Z, 8.5 hours before the alert went out and 147 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Chatham, MA at 12:00Z on 2004-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1264 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Chatham, MA at 12:00Z on 2004-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 115 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1264 J/kg
Mixed-layer CIN
-82 J/kg
Mixed-layer LCL
795 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
115 m²/s²
0-3 km storm-relative helicity
130 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.6

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WUUS51 KBOX 202029
SVRBOX
MAC009-017-202115-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TAUNTON MA
429 PM EDT FRI AUG 20 2004

THE NATIONAL WEATHER SERVICE IN TAUNTON HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  ESSEX COUNTY IN EASTERN MASSACHUSETTS
  THIS INCLUDES THE CITIES OF...LAWRENCE...BEVERLY
  NORTHEASTERN MIDDLESEX COUNTY IN EASTERN MASSACHUSETTS
  THIS INCLUDES THE CITY OF LOWELL

* UNTIL 515 PM EDT

* AT 427 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM.  THIS STORM WAS LOCATED NEAR LOWELL...AND
  MOVING EAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  TEWKSBURY BY 435 PM EDT
  ANDOVER...WILMINGTON AND LAWRENCE BY 440 PM EDT
  NORTH ANDOVER BY 445 PM EDT
  NORTH READING BY 450 PM EDT
  MIDDLETON AND BOXFORD BY 455 PM EDT
  TOPSFIELD AND DANVERS BY 500 PM EDT

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

LAT...LON 4271 7142 4253 7141 4252 7081 4274 7081

$$

BELK

DUNHAM

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Boston/Norton, MA wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 20, 4:18 PM EDT, 11 minutes earlier.

Area forecast discussion, Aug 20, 4:18 PM EDT, 11 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
415 PM FRI AUG 20 2004

...SEVERE THUNDERSTORM WATCH FOR MUCH OF INTERIOR SOUTHERN NEW
ENGLAND AND NORTHEAST COASTAL MASSACHUSETTS UNTIL 7 PM....

.SHORT TERM...TONIGHT AND SATURDAY
COMING SOON

&&

.LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY
MID RANGE ENSEMBLE FORECASTS IN GOOD AGREEMENT REGARDING THE TIMING
OF THE COLD FRONTAL PASSAGE SATURDAY EVENING. WILL KEEP LINGERING
EVENING SHOWERS AND CHANCE FOR THUNDERSTORMS IN THE FORECAST ACROSS
SOUTHEASTERN MASSACHUSETTS AND PORTIONS OF RHODE ISLAND DURING
SATURDAY EVENING. OTHERWISE HIGH PRESSURE IS EXPECTED TO BUILD
ACROSS THE FORECAST AREA SUNDAY...PROVIDING A DRIER AND COOLER DAY.
THE HIGH WILL REMAIN ACROSS THE FORECAST AREA THROUGH MONDAY. A WEAK
COLD FRONT WILL APPROACH FROM THE NORTH MONDAY NIGHT. THE BEST
VORTICITY ADVECTION...STRONGEST AND MOST FAVORABLE WIND FIELDS FOR
DYNAMIC FORCING WILL CROSS NORTHERN NEW ENGLAND. THERE WILL BE
LIMITED MOISTURE ASSOCIATED WITH THIS COLD FRONT WHICH IS EXPECTED
TO REACH THE FORECAST AREA BY DAYBREAK TUESDAY. THUS DID NOT MENTION
CHANCE POPS AT THIS TIME. HIGH PRESSURE WILL BUILD FROM NORTHERN NEW
ENGLAND DURING THE MIDWEEK PERIOD PROVIDING DRY AIR AND SEASONABLE
TEMPERATURES. LOW PRESSURE CROSSING THE WESTERN GREAT LAKES WILL
SEND AN INITIAL SHORT WAVE (INSTABILITY BURST) WITH WARMER AND MORE
HUMID AIR BY FRIDAY. INCLUDED A CHANCE OF SHOWERS FOR DAY 7.

&&

.AVIATION...
COMING SOON

.MARINE...
IN THE LONGER TERM...SOUTHERLY SWELL UP TO 7 FT CAN BE EXPECTED
SATURDAY EVENING...THOUGH THE SWELL IS EXPECTED TO DIMINISH
ON SUNDAY. OTHERWISE WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW
SMALL CRAFT ADVISORY CRITERIA THROUGH WEDNESDAY.

&&

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

.SHORT TERM...DRAG
.LONG TERM...STRAUSS
Hazardous weather outlook, Aug 20, 11:12 AM EDT, 5 hours 17 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TAUNTON MA
1112 AM EDT FRI AUG 20 2004

CTZ002>004-MAZ002>024-026-NHZ011-012-015-RIZ001>008-211113-
BARNSTABLE MA-BLOCK ISLAND RI-BRISTOL RI-CENTRAL MIDDLESEX MA-
CHESHIRE NH-DUKES MA-EASTERN ESSEX MA-EASTERN FRANKLIN MA-
EASTERN HAMPDEN MA-EASTERN HAMPSHIRE MA-EASTERN HILLSBOROUGH NH-
EASTERN KENT RI-EASTERN NORFOLK MA-EASTERN PLYMOUTH MA-HARTFORD CT-
NANTUCKET MA-NEWPORT RI-NORTHERN BRISTOL MA-NORTHERN WORCESTER MA-
NORTHWEST MIDDLESEX MA-NORTHWEST PROVIDENCE RI-
SOUTHEAST MIDDLESEX MA-SOUTHEAST PROVIDENCE RI-SOUTHERN BRISTOL MA-
SOUTHERN PLYMOUTH MA-SOUTHERN WORCESTER MA-SUFFOLK MA-TOLLAND CT-
WASHINGTON RI-WESTERN AND CENTRAL HILLSBOROUGH NH-WESTERN ESSEX MA-
WESTERN FRANKLIN MA-WESTERN HAMPDEN MA-WESTERN HAMPSHIRE MA-
WESTERN KENT RI-WESTERN NORFOLK MA-WESTERN PLYMOUTH MA-WINDHAM CT-
1112 AM EDT FRI AUG 20 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND NORTHEAST
CONNECTICUT...MASSACHUSETTS EAST OF BERKSHIRE COUNTY...SOUTHWEST NEW
HAMPSHIRE AND ALL OF RHODE ISLAND.

.DAY ONE (TODAY AND TONIGHT)...
THIS UPDATE IS TO UPGRADE THE RISK OF STRONG THUNDERSTORMS FROM
HARTFORD AND TOLLAND COUNTIES NORTHEASTWARD THROUGH WORCESTER...
NORFOLK AND SUFFOLK COUNTIES NORTHWARD INTO SOUTHERN NEW HAMPSHIRE
BETWEEN 3 PM AND MIDNIGHT. THE RISK IS FOR DAMAGING WIND AND OR LARGE
HAIL LATE TODAY OR EARLY TONIGHT...ESPECIALLY THE CONNECTICUT RIVER
VALLEY THROUGH WORCESTER COUNTY INTO NORTHERN MIDDLESEX COUNTY
MASSACHUSETTS UP INTO SOUTHWEST NEW HAMPSHIRE (HFD-IJD-OWD-NZW
NORTHWARD).  BRIEF STREET FLOODING RAINS ARE ANTICIPATED... A COUPLE
OF SPOTS MAY RECEIVE 3 INCHES IN 90 MINUTES.  WE ARE EXPECTING THAT
SEVERE WEATHER WILL OCCUR IN AT LEAST TWO COUNTIES BY MIDNIGHT
TONIGHT.  HEAT WILL BE THE DRIVER IN HARTFORD AND HAMPDEN COUNTIES
MID OR LATE AFTERNOON...LOOKING FOR THUNDERSTORMS TO FORM BETWEEN
POUGHKEEPSIE AND LITCHFIELD COUNTY AROUND 3 PM.  FURTHER NORTH A
LONGER DURATION THREAT IS EXPECTED WITH A LATE AFTERNOON PULSE AND
THEN POSSIBLY ANOTHER LATE THIS EVENING.

SKYWARN ACTIVIATION IS ANTICIPATED FOR WITH A POSSIBLE OPERATOR
REQUEST FOR THE OFFICE BEGINNING AROUND 3 OR 4 PM.

.DAYS TWO THROUGH SEVEN (SATURDAY THROUGH THURSDAY)...
LIKELY SHOWERS AND SCATTERED THUNDERSTORMS ARE POSSIBLE SATURDAY
AFTERNOON AND EVENING AS A STRONGER COLD FRONT CROSSES THE REGION
SATURDAY NIGHT.

NO HAZARDOUS WEATHER IS EXPECTED FROM SUNDAY THROUGH THURSDAY.

.SPOTTER CALL TO ACTION STATEMENT...
SPOTTER ACTIVATION IS ANTICIPATED LATE TODAY AS DISCUSSED IN THE DAY
ONE PORTION.

DRAG

In the hours before

Local storm report, Aug 20, 2:54 PM EDT, 1 hour 35 minutes before
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE TAUNTON MA
254 PM EDT FRI AUG 20 2004

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0225 PM     HAIL             ASHBURNHAM              42.63N 71.90W
08/20/2004  1.75 INCH        WORCESTER          MA   TRAINED SPOTTER

0225 PM     HAIL             ASHBURNHAM              42.63N 71.90W
08/20/2004  0.88 INCH        WORCESTER          MA   FIRE DEPT/RESCUE

0250 PM     HAIL             LUNENBURG               42.60N 71.73W
08/20/2004  1.00 INCH        WORCESTER          MA   TRAINED SPOTTER

&&

TLM
Local storm report, Aug 20, 2:55 PM EDT, 1 hour 34 minutes before
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE TAUNTON MA
255 PM EDT FRI AUG 20 2004

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0225 PM     HAIL             ASHBURNHAM              42.63N 71.90W
08/20/2004  0.88 INCH        WORCESTER          MA   FIRE DEPT/RESCUE

0225 PM     HAIL             ASHBURNHAM              42.63N 71.90W
08/20/2004  1.75 INCH        WORCESTER          MA   TRAINED SPOTTER

0250 PM     HAIL             LUNENBURG               42.60N 71.73W
08/20/2004  1.00 INCH        WORCESTER          MA   TRAINED SPOTTER

0255 PM     HAIL             TOWNSEND                42.67N 71.70W
08/20/2004  1.75 INCH        MIDDLESEX          MA   TRAINED SPOTTER

&&

TLM
Local storm report, Aug 20, 3:00 PM EDT, 1 hour 29 minutes before
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE TAUNTON MA
300 PM EDT FRI AUG 20 2004

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0225 PM     HAIL             ASHBURNHAM              42.63N 71.90W
08/20/2004  1.75 INCH        WORCESTER          MA   TRAINED SPOTTER

0225 PM     HAIL             ASHBURNHAM              42.63N 71.90W
08/20/2004  0.88 INCH        WORCESTER          MA   FIRE DEPT/RESCUE

0250 PM     HAIL             LUNENBURG               42.60N 71.73W
08/20/2004  1.00 INCH        WORCESTER          MA   TRAINED SPOTTER

0255 PM     TSTM WND DMG     LUNENBURG               42.60N 71.73W
08/20/2004                   WORCESTER          MA   AMATEUR RADIO

            NUMEROUS TREE LIMBS UP TO 3 INCHES IN DIAMETER DOWN

0255 PM     HAIL             TOWNSEND                42.67N 71.70W
08/20/2004  1.75 INCH        MIDDLESEX          MA   TRAINED SPOTTER

0258 PM     TSTM WND DMG     TOWNSEND                42.67N 71.70W
08/20/2004                   MIDDLESEX          MA   AMATEUR RADIO

            LARGE TREES DOWN

&&

TLM
Local storm report, Aug 20, 3:03 PM EDT, 1 hour 26 minutes before
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE TAUNTON MA
303 PM EDT FRI AUG 20 2004

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0225 PM     HAIL             ASHBURNHAM              42.63N 71.90W
08/20/2004  1.75 INCH        WORCESTER          MA   TRAINED SPOTTER

0225 PM     HAIL             ASHBURNHAM              42.63N 71.90W
08/20/2004  0.88 INCH        WORCESTER          MA   FIRE DEPT/RESCUE

0250 PM     HAIL             LUNENBURG               42.60N 71.73W
08/20/2004  1.00 INCH        WORCESTER          MA   TRAINED SPOTTER

0255 PM     TSTM WND DMG     LUNENBURG               42.60N 71.73W
08/20/2004                   WORCESTER          MA   AMATEUR RADIO

            NUMEROUS TREE LIMBS UP TO 3 INCHES IN DIAMETER DOWN

0255 PM     HAIL             TOWNSEND                42.67N 71.70W
08/20/2004  1.75 INCH        MIDDLESEX          MA   TRAINED SPOTTER

            HAIL DENTING CARS IN THE SOUTHERN PART OF TOWN

0258 PM     TSTM WND DMG     TOWNSEND                42.67N 71.70W
08/20/2004                   MIDDLESEX          MA   AMATEUR RADIO

            LARGE TREES DOWN

&&

TLM
Local storm report, Aug 20, 3:37 PM EDT, 52 minutes before
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE TAUNTON MA
337 PM EDT FRI AUG 20 2004

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0225 PM     HAIL             ASHBURNHAM              42.63N 71.90W
08/20/2004  1.75 INCH        WORCESTER          MA   TRAINED SPOTTER

0225 PM     HAIL             ASHBURNHAM              42.63N 71.90W
08/20/2004  0.88 INCH        WORCESTER          MA   FIRE DEPT/RESCUE

0250 PM     HAIL             LUNENBURG               42.60N 71.73W
08/20/2004  1.00 INCH        WORCESTER          MA   TRAINED SPOTTER

0255 PM     TSTM WND DMG     LUNENBURG               42.60N 71.73W
08/20/2004                   WORCESTER          MA   AMATEUR RADIO

            NUMEROUS TREE LIMBS UP TO 3 INCHES IN DIAMETER DOWN

0255 PM     HAIL             TOWNSEND                42.67N 71.70W
08/20/2004  1.75 INCH        MIDDLESEX          MA   TRAINED SPOTTER

            HAIL DENTING CARS IN THE SOUTHERN PART OF TOWN

0258 PM     TSTM WND DMG     TOWNSEND                42.67N 71.70W
08/20/2004                   MIDDLESEX          MA   AMATEUR RADIO

            LARGE TREES DOWN

0325 PM     TSTM WND DMG     CHELMSFORD              42.60N 71.37W
08/20/2004                   MIDDLESEX          MA   AMATEUR RADIO

            TREES DOWN

&&

TLM
Local storm report, Aug 20, 4:04 PM EDT, 25 minutes before
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE TAUNTON MA
404 PM EDT FRI AUG 20 2004

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0225 PM     HAIL             ASHBURNHAM              42.63N 71.90W
08/20/2004  1.75 INCH        WORCESTER          MA   TRAINED SPOTTER

0225 PM     HAIL             ASHBURNHAM              42.63N 71.90W
08/20/2004  0.88 INCH        WORCESTER          MA   FIRE DEPT/RESCUE

0250 PM     HAIL             LUNENBURG               42.60N 71.73W
08/20/2004  1.00 INCH        WORCESTER          MA   TRAINED SPOTTER

0255 PM     HAIL             TOWNSEND                42.67N 71.70W
08/20/2004  1.75 INCH        MIDDLESEX          MA   TRAINED SPOTTER

            HAIL DENTING CARS IN THE SOUTHERN PART OF TOWN

0255 PM     TSTM WND DMG     LUNENBURG               42.60N 71.73W
08/20/2004                   WORCESTER          MA   AMATEUR RADIO

            NUMEROUS TREE LIMBS UP TO 3 INCHES IN DIAMETER DOWN

0258 PM     TSTM WND DMG     TOWNSEND                42.67N 71.70W
08/20/2004                   MIDDLESEX          MA   AMATEUR RADIO

            LARGE TREES DOWN

0325 PM     HAIL             LOWELL                  42.64N 71.32W
08/20/2004  0.75 INCH        MIDDLESEX          MA   AMATEUR RADIO

            SOUTHERN PART OF TOWN

0325 PM     TSTM WND DMG     CHELMSFORD              42.60N 71.37W
08/20/2004                   MIDDLESEX          MA   AMATEUR RADIO

            TREES DOWN

&&

TLM

The office that day

Everything else NWS Boston/Norton, MA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 20, 1:59 PM EDTSevere Thunderstorm WarningBOXWorcester31 min
Aug 20, 2:07 PM EDTTornado WarningBOXWorcester23 min
Aug 20, 2:28 PM EDTSevere Thunderstorm WarningBOXMiddlesex, Worcester32 min
Aug 20, 2:58 PM EDTSevere Thunderstorm WarningBOXMiddlesex, Worcester47 min
Aug 20, 3:25 PM EDTSevere Thunderstorm WarningBOXEssex, Middlesex50 min
Aug 20, 3:51 PM EDTSpecial Marine WarningBOX84 min
Aug 20, 4:33 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampshire27 min
Aug 20, 5:27 PM EDTSpecial Marine WarningBOX48 min
Aug 20, 6:03 PM EDTSevere Thunderstorm WarningBOXMiddlesex, Worcester42 min
Aug 20, 6:41 PM EDTSevere Thunderstorm WarningBOXMiddlesex, Norfolk, Suffolk49 min
Aug 20, 6:46 PM EDTSpecial Marine WarningBOX89 min
Aug 20, 6:46 PM EDTSpecial Marine WarningBOX89 min

Nearby

Severe Thunderstorm Warnings in Massachusetts, 2004Every severe thunderstorm warning in 2004

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.