Alert archive / Connecticut / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 26, NWS Boston/Norton, MA

June 29, 2021Capitol Planning Region, Northeastern Connecticut Planning Region, Connecticut; Hampden County, Worcester County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jun 29, 2021, 7:34 PM EDT for Capitol Planning Region, Northeastern Connecticut Planning Region, Connecticut; Hampden County, Worcester County, Massachusetts. It was in force for 56 min. 3 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 29, 2021, 7:34 PM EDT (23:34 UTC)
Expired
Jun 29, 2021, 8:30 PM EDT
In force
56 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Capitol Planning Region, CT, Northeastern Connecticut Planning Region, CT, Hampden County, MA, Worcester County, MA

The radar

The Brookhaven radar (KOKX), 104 km from the middle of the area, began a volume at 23:34 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 29, 7:40 PM EDTTSTM WND DMGSomers, CTTREES AND WIRES DOWN ON MAPLE STREET NEAR THE ENFIELD TOWN LINE
Jun 29, 7:55 PM EDTTSTM WND DMGTolland, CTTREES AND WIRES DOWN ON RHODES ROAD
Jun 29, 8:22 PM EDTTSTM WND DMGBolton, CTWIRES DOWN ON RTE 44

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, 11.6 hours before the alert went out and 104 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 2021-06-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 681 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 2021-06-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 132 square meters per square second.1939Sfc1 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
681 J/kg
Mixed-layer CIN
-118 J/kg
Mixed-layer LCL
1052 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
132 m²/s²
0-3 km storm-relative helicity
179 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

795 
WUUS51 KBOX 292334
SVRBOX
CTC003-013-015-MAC013-027-300030-
/O.NEW.KBOX.SV.W.0026.210629T2334Z-210630T0030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
734 PM EDT Tue Jun 29 2021

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Western Windham County in northern Connecticut...
  Tolland County in northern Connecticut...
  Eastern Hartford County in northern Connecticut...
  Southwestern Worcester County in central Massachusetts...
  Southeastern Hampden County in western Massachusetts...

* Until 830 PM EDT.

* At 734 PM EDT, severe thunderstorms were located along a line
  extending from near Longmeadow to near Rocky Hill, moving southeast
  at 20 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Springfield, Hartford, Manchester, East Hartford, Enfield,
  Glastonbury, Vernon, Windsor, Agawam, West Springfield,
  Wethersfield, Mansfield, South Windsor, Windham, Rocky Hill,
  Willimantic, Southbridge, Longmeadow, Suffield and East Longmeadow.

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 these storms. 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 these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4211 7260 4209 7202 4165 7206 4166 7216
      4171 7224 4169 7227 4167 7227 4164 7233
      4161 7233 4159 7239 4160 7241 4159 7242
      4158 7246 4165 7251 4163 7266
TIME...MOT...LOC 2334Z 296DEG 16KT 4208 7256 4167 7262 

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

Loconto
4 follow-up statements
390 
WWUS51 KBOX 292351
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
751 PM EDT Tue Jun 29 2021

MAC013-027-300000-
/O.CAN.KBOX.SV.W.0026.000000T0000Z-210630T0030Z/
Worcester MA-Hampden MA-
751 PM EDT Tue Jun 29 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN WORCESTER AND
SOUTHEASTERN HAMPDEN COUNTIES IS CANCELLED...

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

LAT...LON 4200 7261 4202 7203 4165 7206 4166 7216
      4171 7224 4169 7227 4167 7227 4164 7233
      4161 7233 4163 7246 4165 7251 4164 7266
TIME...MOT...LOC 2350Z 297DEG 18KT 4199 7246 4167 7256 

$$

CTC003-013-015-300030-
/O.CON.KBOX.SV.W.0026.000000T0000Z-210630T0030Z/
Windham CT-Tolland CT-Hartford CT-
751 PM EDT Tue Jun 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM EDT
FOR WESTERN WINDHAM...TOLLAND AND EASTERN HARTFORD COUNTIES...

At 750 PM EDT, severe thunderstorms were located along a line
extending from Somers to Glastonbury, moving southeast at 20 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Hartford, Manchester, East Hartford, Enfield, Glastonbury, Vernon,
Windsor, Wethersfield, Mansfield, South Windsor, Windham, Rocky Hill,
Willimantic, Suffield, Ellington, Tolland, Coventry, Stafford, Somers
and East Windsor.

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 these storms.
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 these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4200 7261 4202 7203 4165 7206 4166 7216
      4171 7224 4169 7227 4167 7227 4164 7233
      4161 7233 4163 7246 4165 7251 4164 7266
TIME...MOT...LOC 2350Z 297DEG 18KT 4199 7246 4167 7256 

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

Loconto
606 
WWUS51 KBOX 300002
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
802 PM EDT Tue Jun 29 2021

CTC003-013-015-300030-
/O.CON.KBOX.SV.W.0026.000000T0000Z-210630T0030Z/
Windham CT-Tolland CT-Hartford CT-
802 PM EDT Tue Jun 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM EDT
FOR WESTERN WINDHAM...TOLLAND AND EASTERN HARTFORD COUNTIES...

At 801 PM EDT, severe thunderstorms were located along a line
extending from Somers to near Glastonbury, moving southeast at 20
mph.

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

SOURCE...Trained weather spotters. Trees and wires were downed in 
         Somers at 740 PM, with trees and wires downed in Tolland at 
         755 PM.       

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

Locations impacted include...
Hartford, Manchester, East Hartford, Enfield, Glastonbury, Vernon,
Windsor, Wethersfield, Mansfield, South Windsor, Windham, Rocky Hill,
Willimantic, Suffield, Ellington, Tolland, Coventry, Stafford, Somers
and East Windsor.

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 these storms.
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 these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4200 7261 4202 7203 4165 7206 4166 7216
      4171 7224 4169 7227 4167 7227 4164 7233
      4161 7233 4163 7246 4165 7251 4164 7266
TIME...MOT...LOC 0001Z 296DEG 16KT 4198 7244 4166 7254 

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

Loconto
903 
WWUS51 KBOX 300013
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
813 PM EDT Tue Jun 29 2021

CTC003-013-015-300030-
/O.CON.KBOX.SV.W.0026.000000T0000Z-210630T0030Z/
Windham CT-Tolland CT-Hartford CT-
813 PM EDT Tue Jun 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM EDT
FOR NORTHWESTERN WINDHAM...TOLLAND AND NORTHEASTERN HARTFORD
COUNTIES...

At 812 PM EDT, severe thunderstorms were located along a line
extending from near Somers to near Marlborough, moving southeast at
20 mph.

HAZARD...60 mph wind gusts.

SOURCE...Trained weather spotters. Trees and power lines were downed 
         in Somers and Tolland from these storms.

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

Locations impacted include...
Manchester, East Hartford, Enfield, Glastonbury, Vernon, Windsor,
Wethersfield, Mansfield, South Windsor, Windham, Rocky Hill,
Willimantic, Ellington, Tolland, Coventry, Stafford, Somers, East
Windsor, Hebron and Woodstock.

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 these storms.
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 these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4196 7261 4201 7230 4202 7203 4177 7205
      4173 7214 4172 7223 4171 7228 4169 7244
      4168 7265
TIME...MOT...LOC 0012Z 296DEG 16KT 4197 7241 4165 7251 

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

Loconto
836 
WWUS51 KBOX 300025
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
825 PM EDT Tue Jun 29 2021

CTC003-013-015-300035-
/O.EXP.KBOX.SV.W.0026.000000T0000Z-210630T0030Z/
Windham CT-Tolland CT-Hartford CT-
825 PM EDT Tue Jun 29 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN WINDHAM...TOLLAND
AND NORTHEASTERN HARTFORD COUNTIES WILL EXPIRE AT 830 PM EDT...
    
The storms which prompted the warning have weakened below severe
limits, and have exited the warned area. Therefore, the warning will
be allowed to expire.  However gusty winds and heavy rain are still
possible with these thunderstorms.

LAT...LON 4196 7261 4201 7230 4202 7203 4177 7205
      4173 7214 4172 7223 4171 7228 4169 7244
      4168 7265
TIME...MOT...LOC 0025Z 296DEG 16KT 4196 7238 4164 7248 

$$

Loconto

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 29, 6:11 PM EDTSevere Thunderstorm WarningBOXNortheastern Connecticut Planning Region64 min
Jun 29, 6:48 PM EDTSevere Thunderstorm WarningBOXCapitol Planning Region57 min
Jun 29, 6:59 PM EDTSevere Thunderstorm WarningBOXCapitol Planning Region44 min
Jun 29, 2:26 AM EDTSmall Craft AdvisoryBOX8 hr
Jun 29, 4:44 PM EDTSpecial Weather StatementBOXHampden31 min
Jun 29, 5:00 PM EDTSpecial Weather StatementBOXNorfolk45 min
Jun 29, 5:34 PM EDTSpecial Weather StatementBOXWorcester41 min
Jun 29, 5:56 PM EDTSpecial Weather StatementBOXFranklin49 min
Jun 29, 6:03 PM EDTSpecial Weather StatementBOXPlymouth42 min
Jun 29, 6:07 PM EDTSpecial Weather StatementBOXHampden, Hampshire38 min
Jun 29, 6:28 PM EDTSpecial Marine WarningBOX47 min
Jun 29, 6:32 PM EDTSpecial Weather StatementBOXHampden43 min
Jun 29, 7:22 PM EDTSpecial Weather StatementBOXHampshire53 min
Jun 29, 7:54 PM EDTSpecial Weather StatementBOXWorcester51 min

Nearby

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