Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 39, NWS Boston/Norton, MA

June 30, 2021Hampden County, Worcester County, Massachusetts; Northeastern Connecticut Planning Region, Connecticut; Providence County, Rhode Island

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jun 30, 2021, 7:15 PM EDT for Hampden County, Worcester County, Massachusetts; Northeastern Connecticut Planning Region, Connecticut; Providence County, Rhode Island. It was in force for 60 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
Jun 30, 2021, 7:15 PM EDT (23:15 UTC)
Expired
Jun 30, 2021, 8:15 PM EDT
In force
60 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, Hampden County, MA, Worcester County, MA, Providence County, RI

The radar

The Boston radar (KBOX), 78 km from the middle of the area, began a volume at 23:17 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

TimeReportWhereRemark
Jun 30, 7:51 PM EDTTSTM WND DMGWoodstock, CTTREE DOWN ON CHILD ROAD
Jun 30, 8:00 PM EDTTSTM WND DMGKillingly, CTWIRES DOWN ON SOAP STREET

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.

IssuedProductOfficeLasted
Jun 30, 3:21 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 11.3 hours before the alert went out and 137 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, Brookhaven, NY at 12:00Z on 2021-06-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 658 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2021-06-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 48 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
658 J/kg
Mixed-layer CIN
-190 J/kg
Mixed-layer LCL
1595 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
48 m²/s²
0-3 km storm-relative helicity
67 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

166 
WUUS51 KBOX 302315
SVRBOX
CTC013-015-MAC013-027-RIC007-010015-
/O.NEW.KBOX.SV.W.0039.210630T2315Z-210701T0015Z/

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

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Northern Windham County in northern Connecticut...
  Northern Tolland County in northern Connecticut...
  Southeastern Worcester County in central Massachusetts...
  Southeastern Hampden County in western Massachusetts...
  Northwestern Providence County in Rhode Island...

* Until 815 PM EDT.

* At 714 PM EDT, a severe thunderstorm was located near Stafford, or
  11 miles north of Mansfield, moving east at 30 mph.

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

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Vernon, Johnston, Milford, Mansfield, Smithfield, Killingly,
  Webster, Southbridge, Burrillville, Northbridge, Ellington,
  Tolland, Wilbraham, Oxford, Uxbridge, Millbury, Charlton, Coventry,
  Stafford and North Smithfield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4182 7243 4213 7247 4217 7155 4183 7153
TIME...MOT...LOC 2314Z 275DEG 27KT 4196 7223 

HAIL...0.75IN
WIND...60MPH
 
$$

Frank
3 follow-up statements
566 
WWUS51 KBOX 302331
SVSBOX

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

CTC013-015-MAC013-027-RIC007-010015-
/O.CON.KBOX.SV.W.0039.000000T0000Z-210701T0015Z/
Windham CT-Tolland CT-Worcester MA-Hampden MA-Providence RI-
731 PM EDT Wed Jun 30 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM EDT
FOR NORTHERN WINDHAM...NORTHERN TOLLAND...SOUTHEASTERN WORCESTER...
SOUTHEASTERN HAMPDEN AND NORTHWESTERN PROVIDENCE COUNTIES...

At 731 PM EDT, a severe thunderstorm was located over Woodstock, or
14 miles northeast of Mansfield, moving east at 30 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Vernon, Johnston, Milford, Mansfield, Smithfield, Killingly, Webster,
Southbridge, Burrillville, Northbridge, Ellington, Tolland,
Wilbraham, Oxford, Uxbridge, Millbury, Charlton, Coventry, Stafford
and North Smithfield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4182 7243 4213 7247 4217 7155 4183 7153
TIME...MOT...LOC 2331Z 275DEG 27KT 4195 7205 

HAIL...0.75IN
WIND...60MPH
 
$$

Frank
832 
WWUS51 KBOX 302337
SVSBOX

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

CTC013-015-MAC013-027-RIC007-010015-
/O.CON.KBOX.SV.W.0039.000000T0000Z-210701T0015Z/
Windham CT-Tolland CT-Worcester MA-Hampden MA-Providence RI-
737 PM EDT Wed Jun 30 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM EDT
FOR NORTHERN WINDHAM...NORTHERN TOLLAND...SOUTHEASTERN WORCESTER...
SOUTHEASTERN HAMPDEN AND NORTHWESTERN PROVIDENCE COUNTIES...

At 735 PM EDT, a severe thunderstorm was located over Woodstock, or
15 miles northeast of Mansfield, moving east at 30 mph.

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

SOURCE...Radar indicated. At 727 PM tree an wires were knocked down 
         in Ellington, Connecticut. At 732 PM, there was a tree down 
         on 27 Sturbridge Road. 

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

Locations impacted include...
Vernon, Johnston, Milford, Mansfield, Smithfield, Killingly, Webster,
Southbridge, Burrillville, Northbridge, Ellington, Tolland,
Wilbraham, Oxford, Uxbridge, Millbury, Charlton, Coventry, Stafford
and North Smithfield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4182 7243 4213 7247 4217 7155 4183 7153
TIME...MOT...LOC 2335Z 275DEG 27KT 4195 7201 

HAIL...0.75IN
WIND...60MPH
 
$$

Frank
700 
WWUS51 KBOX 302357
SVSBOX

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

CTC013-015-MAC013-027-RIC007-010015-
/O.CON.KBOX.SV.W.0039.000000T0000Z-210701T0015Z/
Windham CT-Tolland CT-Worcester MA-Hampden MA-Providence RI-
757 PM EDT Wed Jun 30 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM EDT
FOR NORTHERN WINDHAM...NORTHERN TOLLAND...SOUTHEASTERN WORCESTER...
SOUTHEASTERN HAMPDEN AND NORTHWESTERN PROVIDENCE COUNTIES...

At 757 PM EDT, a severe thunderstorm was located near Putnam, or 15
miles west of Woonsocket, moving east at 30 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Vernon, Johnston, Milford, Mansfield, Smithfield, Killingly, Webster,
Southbridge, Burrillville, Northbridge, Ellington, Tolland,
Wilbraham, Oxford, Uxbridge, Millbury, Charlton, Coventry, Stafford
and North Smithfield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4182 7243 4213 7247 4217 7155 4183 7153
TIME...MOT...LOC 2357Z 275DEG 27KT 4194 7179 

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

Frank

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 30, 2:29 AM EDTSmall Craft AdvisoryBOX18 hr
Jun 30, 3:40 PM EDTSpecial Weather StatementBOXHampshire65 min
Jun 30, 3:42 PM EDTSpecial Weather StatementBOXFranklin63 min
Jun 30, 3:48 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire57 min
Jun 30, 4:03 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampshire57 min
Jun 30, 4:32 PM EDTSevere Thunderstorm WarningBOXFranklin, Middlesex, Worcester58 min
Jun 30, 4:39 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire, Worcester66 min
Jun 30, 4:45 PM EDTTornado WarningBOXFranklin, Worcester26 min
Jun 30, 5:00 PM EDTSevere Thunderstorm WarningBOXMiddlesex, Worcester30 min
Jun 30, 5:13 PM EDTSevere Thunderstorm WarningBOXMiddlesex, Worcester62 min
Jun 30, 5:25 PM EDTSevere Thunderstorm WarningBOXEssex, Middlesex49 min
Jun 30, 5:26 PM EDTSpecial Marine WarningBOX64 min
Jun 30, 5:29 PM EDTSevere Thunderstorm WarningBOXWorcester44 min
Jun 30, 5:43 PM EDTSevere Thunderstorm WarningBOXEssex, Middlesex51 min
Jun 30, 5:54 PM EDTSevere Thunderstorm WarningBOXMiddlesex, Norfolk, Suffolk, Worcester53 min
Jun 30, 5:58 PM EDTSpecial Marine WarningBOX62 min
Jun 30, 6:11 PM EDTSpecial Weather StatementBOXNorfolk49 min
Jun 30, 6:12 PM EDTSevere Thunderstorm WarningBOXMiddlesex, Norfolk, Plymouth, Suffolk, Worcester47 min
Jun 30, 6:22 PM EDTSpecial Marine WarningBOX53 min
Jun 30, 6:31 PM EDTSpecial Marine WarningBOX59 min
Jun 30, 6:45 PM EDTSevere Thunderstorm WarningBOXHampden60 min
Jun 30, 6:57 PM EDTSpecial Marine WarningBOX33 min
Jun 29, 8:23 PM EDTSpecial Weather StatementBOX52 min
Jun 29, 8:25 PM EDTSpecial Weather StatementBOX50 min
Jun 30, 6:39 PM EDTSpecial Weather StatementBOX51 min

Nearby

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