Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 42, NWS Boston/Norton, MA

June 30, 2021Bristol County, Norfolk County, Plymouth County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jun 30, 2021, 8:31 PM EDT for Bristol County, Norfolk County, Plymouth County, Massachusetts. It was in force for 59 min. 7 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: Jun 30, 2021, 8:31 PM EDT (00:31 UTC)
Expired: Jun 30, 2021, 9:30 PM EDT
In force: 59 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Bristol County, MA, Norfolk County, MA, Plymouth County, MA

The radar

The Boston radar (KBOX), 32 km from the middle of the area, began a volume at 00:29 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
Jun 30, 8:33 PM EDT	TSTM WND DMG	Mansfield, MA	TREE AND WIRES DOWN ON PRATT STREET
Jun 30, 8:45 PM EDT	TSTM WND DMG	Easton, MA	MULTIPLE TREES AND WIRES DOWN ON NORTON AVE
Jun 30, 8:45 PM EDT	TSTM WND DMG	Easton, MA	TREE DOWN ON BAY ROAD
Jun 30, 8:50 PM EDT	TSTM WND DMG	Bridgewater, MA	TREE DOWN ON GARAGE ON NORLEN PARK. TREE AND POWER LINES DOWN ON CONANT STREET
Jun 30, 9:00 PM EDT	TSTM WND DMG	Norton, MA	POWER LINES DOWN KILYSYTH ROAD
Jun 30, 9:05 PM EDT	TSTM WND DMG	Halifax, MA	TREES DOWN ON FULLER STREET. TREE DOWN ON SOUTH STREET
Jun 30, 9:15 PM EDT	TSTM WND DMG	Middleborough, MA	TREE AND POWER LINES DOWN ON RIVER ROAD

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
Jun 30, 3:21 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Gray, ME (KGYX), launched 00:00Z, 0.5 hours before the alert went out and 214 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: 505 J/kg
Mixed-layer CIN: -92 J/kg
Mixed-layer LCL: 1353 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 98 m²/s²
0-3 km storm-relative helicity: 125 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

As transmitted.

569 
WUUS51 KBOX 010031
SVRBOX
MAC005-021-023-010130-
/O.NEW.KBOX.SV.W.0042.210701T0031Z-210701T0130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
831 PM EDT Wed Jun 30 2021

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Southeastern Norfolk County in eastern Massachusetts...
  Plymouth County in southeastern Massachusetts...
  Northeastern Bristol County in southeastern Massachusetts...

* Until 930 PM EDT.

* At 831 PM EDT, severe thunderstorms were located along a line
  extending from Walpole to Rehoboth, moving east at 35 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Brockton, Quincy, Plymouth, Taunton, Weymouth, Braintree, Randolph,
  Norwood, Milton, Stoughton, Bridgewater, Marshfield, Dedham,
  Walpole, Mansfield, Middleborough, Easton, Hingham, Wareham and
  Canton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4184 7053 4176 7112 4179 7112 4176 7114
      4220 7130 4227 7084 4224 7077 4225 7077
      4209 7064 4205 7066 4202 7062 4204 7066
      4202 7068 4200 7064 4201 7060 4199 7063
      4201 7071 4195 7065 4192 7054
TIME...MOT...LOC 0031Z 262DEG 40KT 4214 7124 4185 7128 

HAIL...<.75IN
WIND...60MPH
 
$$

Nocera

1 follow-up statement

014 
WWUS51 KBOX 010109
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
909 PM EDT Wed Jun 30 2021

MAC005-010116-
/O.CAN.KBOX.SV.W.0042.000000T0000Z-210701T0130Z/
Bristol MA-
909 PM EDT Wed Jun 30 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN BRISTOL COUNTY IS
CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1000 PM EDT for
eastern and southeastern Massachusetts.

LAT...LON 4184 7053 4180 7086 4191 7093 4203 7097
      4225 7098 4227 7084 4224 7077 4225 7077
      4209 7064 4205 7066 4202 7062 4204 7066
      4202 7068 4200 7064 4201 7060 4199 7063
      4201 7071 4195 7065 4192 7054
TIME...MOT...LOC 0106Z 262DEG 40KT 4219 7074 4190 7078 

$$

MAC021-023-010130-
/O.CON.KBOX.SV.W.0042.000000T0000Z-210701T0130Z/
Norfolk MA-Plymouth MA-
909 PM EDT Wed Jun 30 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM EDT
FOR EAST CENTRAL NORFOLK AND PLYMOUTH COUNTIES...

At 906 PM EDT, severe thunderstorms were located along a line
extending from Scituate to near Carver, moving east at 40 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated. At 845 PM large trees down in Easton, MA 
         and at 905 PM in Halifax, MA multiple trees down.

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

Locations impacted include...
Quincy, Plymouth, Weymouth, Braintree, Bridgewater, Marshfield,
Middleborough, Hingham, Scituate, Pembroke, Rockland, Abington,
Duxbury, Whitman, Hanover, East Bridgewater, Kingston, Carver,
Norwell and Hull.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4184 7053 4180 7086 4191 7093 4203 7097
      4225 7098 4227 7084 4224 7077 4225 7077
      4209 7064 4205 7066 4202 7062 4204 7066
      4202 7068 4200 7064 4201 7060 4199 7063
      4201 7071 4195 7065 4192 7054
TIME...MOT...LOC 0106Z 262DEG 40KT 4219 7074 4190 7078 

HAIL...<.75IN
WIND...60MPH
 
$$

Nocera

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 30, 8:08 PM EDT	Severe Thunderstorm Warning	BOX	Bristol, Norfolk, Worcester	67 min
Jun 30, 8:14 PM EDT	Severe Thunderstorm Warning	BOX	Norfolk, Plymouth, Suffolk	46 min
Jun 30, 8:16 PM EDT	Special Marine Warning	BOX		59 min
Jun 30, 8:41 PM EDT	Special Marine Warning	BOX		64 min
Jun 30, 8:57 PM EDT	Special Marine Warning	BOX		63 min
Jun 30, 9:54 PM EDT	Special Marine Warning	BOX		66 min
Jul 1, 4:01 PM EDT	Special Weather Statement	BOX	Bristol, Plymouth	59 min
Jul 1, 4:02 PM EDT	Small Craft Advisory	BOX		4 days
Jul 1, 4:29 PM EDT	Special Marine Warning	BOX		61 min
Jul 1, 5:03 PM EDT	Special Weather Statement	BOX	Barnstable	42 min
Jul 1, 5:21 PM EDT	Special Marine Warning	BOX		54 min
Jul 1, 7:05 PM EDT	Special Weather Statement	BOX	Hampden	55 min
Jul 1, 7:59 PM EDT	Areal Flood Warning	BOX	Hampden, Hampshire	3 hr

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.