Alert archive / Connecticut / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 38, NWS Boston/Norton, MA

June 30, 2021Hampden County, Massachusetts; Capitol Planning Region, Northeastern Connecticut Planning Region, Connecticut

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jun 30, 2021, 6:45 PM EDT for Hampden County, Massachusetts; Capitol Planning Region, Northeastern Connecticut Planning Region, Connecticut. It was in force for 60 min. 1 report 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, 6:45 PM EDT (22:45 UTC)
Expired
Jun 30, 2021, 7:45 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 Capitol Planning Region, CT, Northeastern Connecticut Planning Region, CT, Hampden County, MA

The radar

The Boston radar (KBOX), 119 km from the middle of the area, began a volume at 22:47 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, 7:27 PM EDTTSTM WND DMGEllington, CTTREE DOWN ON WIRES ON MAPLE 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, 10.8 hours before the alert went out and 119 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.

083 
WUUS51 KBOX 302245
SVRBOX
CTC003-013-015-MAC013-302345-
/O.NEW.KBOX.SV.W.0038.210630T2245Z-210630T2345Z/

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

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Northwestern Windham County in northern Connecticut...
  Tolland County in northern Connecticut...
  Northeastern Hartford County in northern Connecticut...
  Southeastern Hampden County in western Massachusetts...

* Until 745 PM EDT.

* At 644 PM EDT, a severe thunderstorm was located over East Windsor,
  or near South Windsor, 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...
  Springfield, Manchester, Enfield, Vernon, Windsor, Agawam,
  Mansfield, South Windsor, Simsbury, Bloomfield, Avon, Longmeadow,
  Suffield, East Longmeadow, Ellington, Tolland, Windsor Locks,
  Coventry, Stafford and Somers.

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 4181 7285 4203 7284 4212 7218 4180 7213
TIME...MOT...LOC 2244Z 276DEG 28KT 4191 7258 

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

Frank
2 follow-up statements
866 
WWUS51 KBOX 302254
SVSBOX

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

CTC003-013-015-MAC013-302345-
/O.CON.KBOX.SV.W.0038.000000T0000Z-210630T2345Z/
Windham CT-Tolland CT-Hartford CT-Hampden MA-
654 PM EDT Wed Jun 30 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM EDT
FOR NORTHWESTERN WINDHAM...TOLLAND...NORTHEASTERN HARTFORD AND
SOUTHEASTERN HAMPDEN COUNTIES...

At 654 PM EDT, a severe thunderstorm was located over East Windsor,
or near Enfield, moving east at 25 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Springfield, Manchester, Enfield, Vernon, Windsor, Agawam, Mansfield,
South Windsor, Simsbury, Bloomfield, Avon, Longmeadow, Suffield, East
Longmeadow, Ellington, Tolland, Windsor Locks, Coventry, Stafford and
Somers.

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 4181 7285 4203 7284 4212 7218 4180 7213
TIME...MOT...LOC 2254Z 261DEG 20KT 4191 7255 

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

Frank
373 
WWUS51 KBOX 302312
SVSBOX

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

CTC003-013-015-MAC013-302345-
/O.CON.KBOX.SV.W.0038.000000T0000Z-210630T2345Z/
Windham CT-Tolland CT-Hartford CT-Hampden MA-
712 PM EDT Wed Jun 30 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM EDT
FOR NORTHWESTERN WINDHAM...TOLLAND...NORTHEASTERN HARTFORD AND
SOUTHEASTERN HAMPDEN COUNTIES...

At 712 PM EDT, a severe thunderstorm was located over Tolland, or
near Vernon, 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...
Springfield, Manchester, Enfield, Vernon, Windsor, Agawam, Mansfield,
South Windsor, Bloomfield, Longmeadow, Suffield, East Longmeadow,
Ellington, Tolland, Windsor Locks, Coventry, Stafford, Somers, East
Windsor and Southwick.

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 4181 7272 4205 7273 4212 7218 4180 7213
TIME...MOT...LOC 2312Z 276DEG 28KT 4190 7236 

HAIL...0.75IN
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, 6:57 PM EDTSpecial Marine WarningBOX33 min
Jun 30, 7:15 PM EDTSevere Thunderstorm WarningBOXHampden, Worcester60 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 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.