Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 51, NWS Boston/Norton, MA

July 6, 2021Middlesex County, Norfolk County, Worcester County, Massachusetts; Providence County, Rhode Island; Northeastern Connecticut Planning Region, Connecticut

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 6, 2021, 5:21 PM EDT for Middlesex County, Norfolk County, Worcester County, Massachusetts; Providence County, Rhode Island; Northeastern Connecticut Planning Region, Connecticut. It was in force for 42 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
Jul 6, 2021, 5:21 PM EDT (21:21 UTC)
Expired
Jul 6, 2021, 6:03 PM EDT
In force
42 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, Middlesex County, MA, Norfolk County, MA, Worcester County, MA, Providence County, RI

The radar

The Boston radar (KBOX), 57 km from the middle of the area, began a volume at 21:23 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
Jul 6, 5:40 PM EDTTSTM WND DMGDudley, MATREE DOWN ON CHASE AVE

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
Jul 6, 1:13 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 9.4 hours before the alert went out and 150 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 2021-07-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 230 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 2021-07-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 139 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
230 J/kg
Mixed-layer CIN
-195 J/kg
Mixed-layer LCL
1202 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
139 m²/s²
0-3 km storm-relative helicity
184 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

054 
WUUS51 KBOX 062121
SVRBOX
CTC015-MAC017-021-027-RIC007-062215-
/O.NEW.KBOX.SV.W.0051.210706T2121Z-210706T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
521 PM EDT Tue Jul 6 2021

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Northeastern Windham County in northern Connecticut...
  West central Norfolk County in eastern Massachusetts...
  Southeastern Worcester County in central Massachusetts...
  South central Middlesex County in northeastern Massachusetts...
  Providence County in Rhode Island...

* Until 615 PM EDT.

* At 521 PM EDT, a severe thunderstorm was located over Dudley, or 16
  miles southwest of Worcester, 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...
  Worcester, Cranston, Framingham, Woonsocket, Shrewsbury,
  Cumberland, North Providence, Johnston, Milford, Plainfield,
  Smithfield, Lincoln, Westborough, Grafton, Killingly, Webster,
  Southbridge, Ashland, Bellingham and Auburn.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4174 7210 4229 7203 4230 7142 4175 7150
TIME...MOT...LOC 2121Z 281DEG 26KT 4205 7194 

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

Frank
2 follow-up statements
773 
WWUS51 KBOX 062147
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
547 PM EDT Tue Jul 6 2021

CTC015-MAC017-021-027-RIC007-062215-
/O.CON.KBOX.SV.W.0051.000000T0000Z-210706T2215Z/
Windham CT-Norfolk MA-Worcester MA-Middlesex MA-Providence RI-
547 PM EDT Tue Jul 6 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR NORTHEASTERN WINDHAM...WEST CENTRAL NORFOLK...SOUTHEASTERN
WORCESTER...SOUTH CENTRAL MIDDLESEX AND PROVIDENCE COUNTIES...

At 546 PM EDT, a severe thunderstorm was located near Douglas, or 11
miles west of Woonsocket, 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...
Cranston, Framingham, Woonsocket, Cumberland, North Providence,
Johnston, Milford, Plainfield, Smithfield, Lincoln, Grafton,
Killingly, Webster, Southbridge, Ashland, Bellingham, Burrillville,
Northbridge, Hopkinton and Oxford.

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 this storm.
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.

&&

LAT...LON 4174 7210 4206 7205 4230 7142 4175 7150
TIME...MOT...LOC 2146Z 281DEG 26KT 4202 7171 

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

RM
118 
WWUS51 KBOX 062203
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
603 PM EDT Tue Jul 6 2021

CTC015-MAC017-021-027-RIC007-062212-
/O.CAN.KBOX.SV.W.0051.000000T0000Z-210706T2215Z/
Windham CT-Norfolk MA-Worcester MA-Middlesex MA-Providence RI-
603 PM EDT Tue Jul 6 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN WINDHAM...WEST
CENTRAL NORFOLK...SOUTHEASTERN WORCESTER...SOUTH CENTRAL MIDDLESEX
AND PROVIDENCE COUNTIES IS CANCELLED...
    
The severe thunderstorm which prompted the warning remains severe 
and a new Severe Thunderstorm Warning has been issued until 645 PM 
for Providence and Windham Counties. Therefore, the original warning 
has been cancelled. 

A Severe Thunderstorm Watch remains in effect until 800 PM EDT for
northern Connecticut...eastern, central and northeastern
Massachusetts...and Rhode Island.

Remember, a Severe Thunderstorm Warning still remains in effect for
Providence and Windham Counties until 645 PM.

LAT...LON 4174 7210 4206 7205 4230 7142 4175 7150
TIME...MOT...LOC 2154Z 281DEG 26KT 4200 7156 

$$

Loconto

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 6, 1:42 AM EDTSpecial Weather StatementBOXFranklin33 min
Jul 6, 1:57 AM EDTSpecial Weather StatementBOXFranklin33 min
Jul 6, 2:20 AM EDTSpecial Weather StatementBOXFranklin25 min
Jul 6, 2:34 AM EDTSpecial Weather StatementBOXWorcester41 min
Jul 6, 3:33 AM EDTHeat AdvisoryBOXBristol, Essex, Franklin, Hampden, Hampshire, Middlesex and 4 more39 hr
Jul 6, 2:14 PM EDTSpecial Weather StatementBOXFranklin46 min
Jul 6, 3:02 PM EDTSpecial Weather StatementBOXHampshire43 min
Jul 6, 3:06 PM EDTSpecial Weather StatementBOXHampden39 min
Jul 6, 3:12 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire63 min
Jul 6, 3:36 PM EDTSpecial Weather StatementBOXHampden39 min
Jul 6, 3:49 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampshire, Worcester56 min
Jul 6, 4:13 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire, Worcester40 min
Jul 6, 4:20 PM EDTSevere Thunderstorm WarningBOXHampden, Hampshire55 min
Jul 6, 4:42 PM EDTSpecial Weather StatementBOXMiddlesex, Worcester48 min
Jul 6, 4:43 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire, Worcester62 min
Jul 6, 4:51 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire, Worcester33 min
Jul 6, 5:13 PM EDTSevere Thunderstorm WarningBOXEssex, Middlesex, Suffolk, Worcester62 min
Jul 6, 5:16 PM EDTSpecial Marine WarningBOX44 min
Jul 6, 5:19 PM EDTSpecial Weather StatementBOXEssex41 min
Jul 6, 5:21 PM EDTSpecial Marine WarningBOX39 min
Jul 6, 5:52 PM EDTSevere Thunderstorm WarningBOXBristol, Middlesex, Norfolk, Worcester53 min
Jul 6, 5:54 PM EDTSpecial Marine WarningBOX66 min
Jul 6, 5:57 PM EDTSpecial Marine WarningBOX48 min
Jul 6, 6:00 PM EDTSpecial Weather StatementBOXEssex30 min
Jul 6, 6:07 PM EDTSpecial Marine WarningBOX23 min
Jul 6, 6:13 PM EDTSevere Thunderstorm WarningBOXBristol, Middlesex, Norfolk, Plymouth, Suffolk31 min
Jul 6, 6:37 PM EDTSpecial Marine WarningBOX23 min
Jul 6, 6:45 PM EDTSpecial Weather StatementBOXBristol, Plymouth45 min
Jul 6, 6:52 PM EDTSpecial Marine WarningBOX53 min
Jul 6, 6:58 PM EDTSpecial Weather StatementBOXWashington32 min
Jul 6, 5:00 PM EDTSevere Thunderstorm WarningBOXCapitol Planning Region, Northeastern Connecticut Planning Region60 min

Nearby

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