Alert archive / Connecticut / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 101, NWS Boston/Norton, MA

August 12, 2021Capitol Planning Region, Northeastern Connecticut Planning Region, Connecticut

NWS Boston/Norton, MA issued this severe thunderstorm warning at Aug 12, 2021, 6:26 PM EDT for Capitol Planning Region, Northeastern Connecticut Planning Region, Connecticut. It was in force for 49 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
Aug 12, 2021, 6:26 PM EDT (22:26 UTC)
Expired
Aug 12, 2021, 7:15 PM EDT
In force
49 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Capitol Planning Region, CT, Northeastern Connecticut Planning Region, CT

The radar

The Brookhaven radar (KOKX), 105 km from the middle of the area, began a volume at 22:30 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
Aug 12, 6:40 PM EDTTSTM WND DMGWillington, CTTREES 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, 10.4 hours before the alert went out and 105 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 2021-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 278 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 2021-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -82 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
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.

992 
WUUS51 KBOX 122226
SVRBOX
CTC003-013-015-122330-
/O.NEW.KBOX.SV.W.0101.210812T2226Z-210812T2330Z/

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

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Southern Windham County in northern Connecticut...
  Tolland County in northern Connecticut...
  Central Hartford County in northern Connecticut...

* Until 730 PM EDT.

* At 625 PM EDT, severe thunderstorms were located along a line
  extending from Stafford to Canton, moving east at 25 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Expect wind damage to trees and power lines. Minor hail 
           damage to vehicles is possible.

* Locations impacted include...
  Hartford, New Britain, West Hartford, Manchester, East Hartford,
  Glastonbury, Newington, Vernon, Windsor, Wethersfield, Mansfield,
  South Windsor, Farmington, Windham, Simsbury, Bloomfield, Berlin,
  Rocky Hill, Avon and Willimantic.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4181 7295 4183 7294 4184 7294 4185 7295
      4187 7295 4199 7226 4177 7185 4171 7223
      4171 7225 4162 7277 4180 7299
TIME...MOT...LOC 2225Z 281DEG 20KT 4197 7232 4187 7293 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Nash
2 follow-up statements
853 
WWUS51 KBOX 122259
SVSBOX

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

CTC003-122308-
/O.CAN.KBOX.SV.W.0101.000000T0000Z-210812T2330Z/
Hartford CT-
659 PM EDT Thu Aug 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL HARTFORD COUNTY IS
CANCELLED...

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

LAT...LON 4172 7217 4176 7228 4186 7202 4177 7185
TIME...MOT...LOC 2258Z 286DEG 24KT 4179 7195 4175 7213 

$$

CTC013-015-122330-
/O.CON.KBOX.SV.W.0101.000000T0000Z-210812T2330Z/
Windham CT-Tolland CT-
659 PM EDT Thu Aug 12 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM EDT
FOR CENTRAL WINDHAM AND EAST CENTRAL TOLLAND COUNTIES...

At 658 PM EDT, severe thunderstorms were located along a line
extending from Brooklyn to near Chaplin, moving east at 25 mph.

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

SOURCE...Radar indicated.

IMPACT...Expect wind damage to trees and power lines. Minor hail 
         damage to vehicles is possible.

Locations impacted include...
Mansfield, Windham, Killingly, Brooklyn, Canterbury, Pomfret,
Chaplin, Hampton, Eastford and Scotland.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4172 7217 4176 7228 4186 7202 4177 7185
TIME...MOT...LOC 2258Z 286DEG 24KT 4179 7195 4175 7213 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Nash
422 
WWUS51 KBOX 122315
SVSBOX

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

CTC013-015-122325-
/O.CAN.KBOX.SV.W.0101.000000T0000Z-210812T2330Z/
Windham CT-Tolland CT-
715 PM EDT Thu Aug 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL WINDHAM AND EAST
CENTRAL TOLLAND COUNTIES IS CANCELLED...
    
The storms which prompted the warning have weakened below severe
limits, and have exited the warned area. Therefore, the warning has
been cancelled.

LAT...LON 4172 7217 4176 7228 4186 7202 4177 7185
TIME...MOT...LOC 2314Z 281DEG 20KT 4177 7183 4173 7201 

$$

Nash

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 2:53 PM EDTHeat AdvisoryBOXCapitol Planning Region, Northeastern Connecticut Planning Region29 hr
Aug 12, 5:35 PM EDTSevere Thunderstorm WarningBOXCapitol Planning Region55 min
Aug 12, 6:13 PM EDTSevere Thunderstorm WarningBOXNortheastern Connecticut Planning Region62 min

Nearby

Severe Thunderstorm Warnings in Connecticut, 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.