Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 63, NWS Boston/Norton, MA

July 7, 20215 counties in Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 7, 2021, 6:59 PM EDT for 5 counties in Massachusetts. It was in force for 61 min. 9 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 7, 2021, 6:59 PM EDT (22:59 UTC)
Expired: Jul 7, 2021, 8:00 PM EDT
In force: 61 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Hail: 0.88 in
Wind: 60.0 mph

Counties Bristol County, MA, Middlesex County, MA, Norfolk County, MA, Plymouth County, MA, Suffolk County, MA

The radar

The Boston radar (KBOX), 37 km from the middle of the area, began a volume at 23:01 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.

What was reported inside it

Time	Report	Where	Remark
Jul 7, 7:17 PM EDT	TSTM WND DMG	Dover, MA	MULTIPLE TREES DOWN ON FARM STREET
Jul 7, 7:17 PM EDT	TSTM WND DMG	Dover, MA	TREE DOWN ON WIRES ON STRAWBERRY HILL STREET
Jul 7, 7:17 PM EDT	TSTM WND GST 75	Blue Hill Coop, MA
Jul 7, 7:25 PM EDT	TSTM WND DMG	Dedham, MA	TREES AND WIRES DOWN ON LANCASTER ROAD
Jul 7, 7:35 PM EDT	TSTM WND DMG	Jamaica Plain, MA	TREES DOWN ON ON RIVER STREET AND PINE STREET
Jul 7, 7:50 PM EDT	TSTM WND DMG	Rockland, MA	TREE DOWN ON POND STREET
Jul 7, 7:50 PM EDT	TSTM WND DMG	Weymouth, MA	TREE AND WIRES DOWN WEST LAKE DRIVE
Jul 7, 7:50 PM EDT	TSTM WND DMG	Weymouth, MA	WIRES DOWN ON OAK STREET
Jul 7, 7:50 PM EDT	HAIL 1	Weymouth, MA

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

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

Issued	Product	Office	Lasted
Jul 7, 2:41 PM EDT	Severe Thunderstorm Watch	SPC	10 hr

The nearest sounding before it

Gray, ME (KGYX), launched 12:00Z, 11.0 hours before the alert went out and 190 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1184 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 2 m²/s²
0-3 km storm-relative helicity: 30 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

455 
WUUS51 KBOX 072259
SVRBOX
MAC005-017-021-023-025-080000-
/O.NEW.KBOX.SV.W.0063.210707T2259Z-210708T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
659 PM EDT Wed Jul 7 2021

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Suffolk County in eastern Massachusetts...
  Norfolk County in eastern Massachusetts...
  Southeastern Middlesex County in northeastern Massachusetts...
  Northwestern Plymouth County in southeastern Massachusetts...
  North central Bristol County in southeastern Massachusetts...

* Until 800 PM EDT.

* At 659 PM EDT, a severe thunderstorm was located over Medfield, or
  near Norwood, moving east at 10 mph.

  HAZARD...60 mph wind gusts and nickel size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to trees and power lines.

* Locations impacted include...
  Boston, Brockton, Quincy, Newton, Framingham, Brookline, Weymouth,
  Braintree, Natick, Randolph, Franklin, Needham, Norwood, Wellesley,
  Milton, Stoughton, Dedham, Walpole, Mansfield and Easton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Large hail and damaging winds and continuous cloud to ground
lightning is occurring with this storm. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4236 7103 4236 7099 4234 7102 4232 7100
      4233 7104 4231 7103 4230 7105 4229 7102
      4232 7101 4230 7100 4231 7097 4229 7101
      4226 7097 4228 7095 4225 7096 4225 7094
      4205 7088 4203 7143 4231 7141
TIME...MOT...LOC 2259Z 254DEG 8KT 4219 7129 

HAIL...0.88IN
WIND...60MPH
 
$$

Loconto

4 follow-up statements

730 
WWUS51 KBOX 072314
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
714 PM EDT Wed Jul 7 2021

MAC005-017-021-023-025-080000-
/O.CON.KBOX.SV.W.0063.000000T0000Z-210708T0000Z/
Suffolk MA-Norfolk MA-Middlesex MA-Plymouth MA-Bristol MA-
714 PM EDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM EDT
FOR SUFFOLK...NORFOLK...SOUTHEASTERN MIDDLESEX...NORTHWESTERN
PLYMOUTH AND NORTH CENTRAL BRISTOL COUNTIES...

At 714 PM EDT, a severe thunderstorm was located over Westwood, or
over Norwood, moving east at 10 mph.

HAZARD...70 mph wind gusts and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Expect considerable damage to trees and power lines. Damage 
         is likely to mobile homes and outbuildings.

Locations impacted include...
Boston, Brockton, Quincy, Newton, Framingham, Brookline, Weymouth,
Braintree, Natick, Randolph, Franklin, Needham, Norwood, Wellesley,
Milton, Stoughton, Dedham, Walpole, Mansfield and Easton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4236 7103 4236 7099 4234 7102 4232 7100
      4233 7104 4231 7103 4230 7105 4229 7102
      4232 7101 4230 7100 4231 7097 4229 7101
      4226 7097 4228 7095 4225 7096 4225 7094
      4205 7088 4203 7143 4231 7141
TIME...MOT...LOC 2314Z 254DEG 8KT 4220 7125 

HAIL...0.88IN
WIND...70MPH
 
$$

Loconto

827 
WWUS51 KBOX 072330
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
730 PM EDT Wed Jul 7 2021

MAC005-017-021-023-025-080000-
/O.CON.KBOX.SV.W.0063.000000T0000Z-210708T0000Z/
Suffolk MA-Norfolk MA-Middlesex MA-Plymouth MA-Bristol MA-
730 PM EDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM EDT
FOR SUFFOLK...NORFOLK...EAST CENTRAL MIDDLESEX...NORTHWESTERN
PLYMOUTH AND NORTH CENTRAL BRISTOL COUNTIES...

At 729 PM EDT, a severe thunderstorm was located over Westwood, or
over Norwood, moving east at 10 mph.

HAZARD...70 mph wind gusts and nickel size hail.

SOURCE...Trained weather spotters. At 717 PM multiple trees and 
         powerlines were downed in Dover.

IMPACT...Expect considerable damage to trees and power lines. Damage 
         is likely to mobile homes and outbuildings.

Locations impacted include...
Boston, Brockton, Quincy, Newton, Brookline, Weymouth, Braintree,
Randolph, Needham, Norwood, Wellesley, Milton, Stoughton, Dedham,
Walpole, Mansfield, Easton, Hingham, Canton and Sharon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4236 7103 4236 7099 4234 7102 4232 7100
      4233 7104 4231 7103 4230 7105 4229 7102
      4232 7101 4231 7100 4231 7097 4229 7101
      4226 7097 4228 7095 4225 7096 4225 7094
      4205 7088 4204 7114 4211 7133 4233 7127
TIME...MOT...LOC 2329Z 254DEG 8KT 4221 7121 

HAIL...0.88IN
WIND...70MPH
 
$$

Loconto

236 
WWUS51 KBOX 072340
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
740 PM EDT Wed Jul 7 2021

MAC005-017-021-023-025-080000-
/O.CON.KBOX.SV.W.0063.000000T0000Z-210708T0000Z/
Suffolk MA-Norfolk MA-Middlesex MA-Plymouth MA-Bristol MA-
740 PM EDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM EDT
FOR SOUTHWESTERN SUFFOLK...NORTHEASTERN NORFOLK...SOUTHEASTERN
MIDDLESEX...NORTHWESTERN PLYMOUTH AND NORTH CENTRAL BRISTOL
COUNTIES...

At 739 PM EDT, a severe thunderstorm was located over Holbrook, or
over Braintree, moving east at 15 mph.

HAZARD...70 mph wind gusts and ping pong ball size hail.

SOURCE...Trained weather spotters. Numerous trees and powerlines are 
         downed in Dedham, Canton, and Dover from this storm.

IMPACT...Expect considerable damage to trees and power lines. Wind 
         damage is also likely to mobile homes, roofs, and 
         outbuildings. Minor hail damage to vehicles is possible.

Locations impacted include...
Boston, Brockton, Quincy, Newton, Brookline, Weymouth, Braintree,
Randolph, Norwood, Milton, Stoughton, Dedham, Easton, Hingham,
Canton, Rockland, Abington, Westwood, Whitman and East Bridgewater.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4234 7102 4232 7100 4233 7104 4231 7103
      4230 7105 4229 7102 4232 7101 4231 7100
      4231 7097 4229 7101 4226 7097 4228 7095
      4225 7096 4225 7094 4205 7088 4208 7112
      4217 7116 4230 7119
TIME...MOT...LOC 2339Z 269DEG 14KT 4217 7100 

HAIL...1.50IN
WIND...70MPH
 
$$

Loconto

852 
WWUS51 KBOX 072354
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
754 PM EDT Wed Jul 7 2021

MAC005-017-021-023-025-080002-
/O.EXP.KBOX.SV.W.0063.000000T0000Z-210708T0000Z/
Suffolk MA-Norfolk MA-Middlesex MA-Plymouth MA-Bristol MA-
754 PM EDT Wed Jul 7 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN SUFFOLK...
NORTHEASTERN NORFOLK...SOUTHEASTERN MIDDLESEX...NORTHWESTERN PLYMOUTH
AND NORTH CENTRAL BRISTOL COUNTIES WILL EXPIRE AT 800 PM EDT...
        
The storm which prompted the warning has moved out of much of the 
area. Therefore the warning will be allowed to expire. However the 
storm remains severe and a Severe Thunderstorm Warning has been 
issued for northern Plymouth and far eastern Norfolk Counties until 
845 PM.

A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
eastern, southeastern and northeastern Massachusetts.

LAT...LON 4234 7102 4232 7100 4233 7104 4231 7103
      4230 7105 4229 7102 4232 7101 4231 7100
      4231 7097 4229 7101 4226 7097 4228 7095
      4225 7096 4225 7094 4205 7088 4208 7112
      4217 7116 4230 7119
TIME...MOT...LOC 2352Z 254DEG 8KT 4218 7097 

$$

Loconto

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 7, 4:00 PM EDT	Severe Thunderstorm Warning	BOX	Hampden, Hampshire	60 min
Jul 7, 4:01 PM EDT	Severe Thunderstorm Warning	BOX	Franklin, Hampshire	59 min
Jul 7, 4:05 PM EDT	Special Weather Statement	BOX	Essex	40 min
Jul 7, 4:33 PM EDT	Severe Thunderstorm Warning	BOX	Essex, Middlesex	57 min
Jul 7, 5:02 PM EDT	Special Weather Statement	BOX	Worcester	43 min
Jul 7, 5:05 PM EDT	Special Marine Warning	BOX		25 min
Jul 7, 5:10 PM EDT	Tropical Storm Watch	BOX	Barnstable, Bristol, Dukes, Nantucket, Plymouth	13 hr
Jul 7, 5:21 PM EDT	Severe Thunderstorm Warning	BOX	Hampden, Hampshire, Worcester	54 min
Jul 7, 5:24 PM EDT	Special Marine Warning	BOX		66 min
Jul 7, 5:30 PM EDT	Severe Thunderstorm Warning	BOX	Hampden, Worcester	60 min
Jul 7, 6:01 PM EDT	Special Weather Statement	BOX	Worcester	44 min
Jul 7, 6:17 PM EDT	Severe Thunderstorm Warning	BOX	Bristol, Middlesex, Norfolk, Worcester	58 min
Jul 7, 6:18 PM EDT	Severe Thunderstorm Warning	BOX	Middlesex, Worcester	36 min
Jul 7, 6:22 PM EDT	Special Marine Warning	BOX		53 min
Jul 7, 7:18 PM EDT	Special Marine Warning	BOX		57 min
Jul 7, 7:47 PM EDT	Severe Thunderstorm Warning	BOX	Norfolk, Plymouth	25 min
Jul 7, 7:51 PM EDT	Special Marine Warning	BOX		54 min

Nearby

Severe Thunderstorm Warnings in Massachusetts, 2021 Every severe thunderstorm warning in 2021

Sources

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