Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 100, NWS Boston/Norton, MA

August 12, 20215 counties in Massachusetts; Providence County, Rhode Island; Northeastern Connecticut Planning Region, Connecticut

NWS Boston/Norton, MA issued this severe thunderstorm warning at Aug 12, 2021, 6:13 PM EDT for 5 counties in Massachusetts; Providence County, Rhode Island; Northeastern Connecticut Planning Region, Connecticut. It was in force for 62 min. 2 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: Aug 12, 2021, 6:13 PM EDT (22:13 UTC)
Expired: Aug 12, 2021, 7:15 PM EDT
In force: 62 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Northeastern Connecticut Planning Region, CT, Bristol County, MA, Hampden County, MA, Middlesex County, MA, Norfolk County, MA, Worcester County, MA, Providence County, RI

The radar

The Boston radar (KBOX), 46 km from the middle of the area, began a volume at 22:12 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
Aug 12, 6:38 PM EDT	TSTM WND DMG	Worcester, MA	TREES AND WIRES DOWN ON FERDINAND STREET
Aug 12, 6:40 PM EDT	TSTM WND DMG	Willington, CT	TREES DOWN ON ELDRIDGE MILLS ROAD

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 10.2 hours before the alert went out and 175 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: 278 J/kg
Mixed-layer CIN: -162 J/kg
Mixed-layer LCL: 1400 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: -82 m²/s²
0-3 km storm-relative helicity: -47 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

668 
WUUS51 KBOX 122213
SVRBOX
CTC013-015-MAC005-013-017-021-027-RIC007-122315-
/O.NEW.KBOX.SV.W.0100.210812T2213Z-210812T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
613 PM EDT Thu Aug 12 2021

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Northern Windham County in northern Connecticut...
  Northeastern Tolland County in northern Connecticut...
  Western Norfolk County in eastern Massachusetts...
  Southern Worcester County in central Massachusetts...
  Southeastern Middlesex County in northeastern Massachusetts...
  Southeastern Hampden County in western Massachusetts...
  Northwestern Bristol County in southeastern Massachusetts...
  Providence County in Rhode Island...

* Until 715 PM EDT.

* At 612 PM EDT, severe thunderstorms were located along a line
  extending from Spencer to near Willington, moving east at 45 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Worcester, Providence, Newton, Pawtucket, Framingham, Woonsocket,
  Marlborough, Shrewsbury, Cumberland, Natick, North Providence,
  Franklin, Needham, Johnston, North Attleborough, Milford,
  Wellesley, Attleboro, Dedham and Walpole.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These storms have produced wind damage. For your protection move to 
an interior room on the lowest floor of a building.

&&

LAT...LON 4235 7117 4181 7141 4186 7238 4236 7204
TIME...MOT...LOC 2212Z 268DEG 38KT 4227 7201 4193 7225 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Nash

2 follow-up statements

609 
WWUS51 KBOX 122243
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
643 PM EDT Thu Aug 12 2021

MAC013-122251-
/O.CAN.KBOX.SV.W.0100.000000T0000Z-210812T2315Z/
Hampden MA-
643 PM EDT Thu Aug 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN HAMPDEN COUNTY IS
CANCELLED...

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

LAT...LON 4235 7117 4181 7141 4186 7233 4209 7193
      4232 7194
TIME...MOT...LOC 2241Z 280DEG 30KT 4227 7174 4187 7185 

$$

CTC013-015-MAC005-017-021-027-RIC007-122315-
/O.CON.KBOX.SV.W.0100.000000T0000Z-210812T2315Z/
Windham CT-Tolland CT-Norfolk MA-Worcester MA-Middlesex MA-
Bristol MA-Providence RI-
643 PM EDT Thu Aug 12 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM EDT
FOR NORTHERN WINDHAM...EAST CENTRAL TOLLAND...WESTERN NORFOLK...
SOUTHEASTERN WORCESTER...SOUTHEASTERN MIDDLESEX...NORTHWESTERN
BRISTOL AND PROVIDENCE COUNTIES...

At 641 PM EDT, severe thunderstorms were located along a line
extending from Shrewsbury to near Putnam, moving east at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Worcester, Providence, Newton, Pawtucket, Framingham, Woonsocket,
Marlborough, Shrewsbury, Cumberland, Natick, North Providence,
Franklin, Needham, Johnston, North Attleborough, Milford, Wellesley,
Attleboro, Dedham and Walpole.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These storms have been producing wind damage. For your protection 
move to an interior room on the lowest floor of a building.

&&

LAT...LON 4235 7117 4181 7141 4186 7233 4209 7193
      4232 7194
TIME...MOT...LOC 2241Z 280DEG 30KT 4227 7174 4187 7185 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Nash

057 
WWUS51 KBOX 122310
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
710 PM EDT Thu Aug 12 2021

CTC013-015-MAC005-017-021-027-RIC007-122319-
/O.EXP.KBOX.SV.W.0100.000000T0000Z-210812T2315Z/
Windham CT-Tolland CT-Norfolk MA-Worcester MA-Middlesex MA-
Bristol MA-Providence RI-
710 PM EDT Thu Aug 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN WINDHAM...EAST
CENTRAL TOLLAND...WESTERN NORFOLK...SOUTHEASTERN WORCESTER...
SOUTHEASTERN MIDDLESEX...NORTHWESTERN BRISTOL AND PROVIDENCE COUNTIES
WILL EXPIRE AT 715 PM EDT...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire.

LAT...LON 4235 7117 4181 7141 4186 7233 4209 7193
      4232 7194
TIME...MOT...LOC 2309Z 268DEG 32KT 4207 7143 4183 7161 

$$

Nash

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 12, 2:53 PM EDT	Heat Advisory	BOX	Barnstable, Bristol, Essex, Franklin, Hampden, Hampshire and 5 more	29 hr
Aug 12, 3:45 PM EDT	Special Weather Statement	BOX	Franklin, Hampshire	60 min
Aug 12, 4:45 PM EDT	Special Weather Statement	BOX	Franklin, Hampden, Hampshire	60 min
Aug 12, 5:02 PM EDT	Severe Thunderstorm Warning	BOX	Franklin, Hampden, Hampshire	58 min
Aug 12, 5:35 PM EDT	Severe Thunderstorm Warning	BOX	Hampden, Hampshire, Worcester	55 min
Aug 12, 5:42 PM EDT	Special Weather Statement	BOX	Worcester	48 min
Aug 12, 5:51 PM EDT	Severe Thunderstorm Warning Considerable damage threat	BOX	Franklin, Hampden, Hampshire, Worcester	39 min
Aug 12, 6:52 PM EDT	Special Marine Warning	BOX		53 min
Aug 12, 7:14 PM EDT	Special Weather Statement	BOX	Bristol, Plymouth	61 min
Aug 12, 6:26 PM EDT	Severe Thunderstorm Warning	BOX	Capitol Planning Region, Northeastern Connecticut Planning Region	49 min

Nearby

Severe Thunderstorm Warnings in Massachusetts, 2021 Severe Thunderstorm Warnings in Connecticut, 2021 Severe Thunderstorm Warnings in Rhode Island, 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.