Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 118, NWS Boston/Norton, MA

September 28, 20215 counties in Massachusetts; Providence County, Rhode Island

NWS Boston/Norton, MA issued this severe thunderstorm warning at Sep 28, 2021, 9:29 AM EDT for 5 counties in Massachusetts; Providence County, Rhode Island. It was in force for 61 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: Sep 28, 2021, 9:29 AM EDT (13:29 UTC)
Expired: Sep 28, 2021, 10:30 AM EDT
In force: 61 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

Counties Bristol County, MA, Middlesex County, MA, Norfolk County, MA, Suffolk County, MA, Worcester County, MA, Providence County, RI

The radar

The Boston radar (KBOX), 21 km from the middle of the area, began a volume at 13:28 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

Time	Report	Where	Remark
Sep 28, 9:40 AM EDT	HAIL 0.75	Cumberland, RI	TRAINED SPOTTER

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, 1.5 hours before the alert went out and 195 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 116 J/kg
Mixed-layer CIN: -338 J/kg
Mixed-layer LCL: 1298 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 118 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

594 
WUUS51 KBOX 281329
SVRBOX
MAC005-017-021-025-027-RIC007-281430-
/O.NEW.KBOX.SV.W.0118.210928T1329Z-210928T1430Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
929 AM EDT Tue Sep 28 2021

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Southwestern Suffolk County in eastern Massachusetts...
  Norfolk County in eastern Massachusetts...
  Southeastern Worcester County in central Massachusetts...
  Southeastern Middlesex County in northeastern Massachusetts...
  Northwestern Bristol County in southeastern Massachusetts...
  Northeastern Providence County in Rhode Island...

* Until 1030 AM EDT.

* At 928 AM EDT, a severe thunderstorm was located over Woonsocket,
  moving northeast at 35 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Minor hail damage to vehicles is possible.

* Locations impacted include...
  Boston, Worcester, Quincy, Newton, Framingham, Waltham, Brookline,
  Weymouth, Arlington, Woonsocket, Braintree, Shrewsbury, Cumberland,
  Natick, Randolph, Watertown, Franklin, Lexington, Needham and North
  Attleborough.

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 4214 7097 4210 7108 4202 7107 4186 7156
      4222 7183 4243 7120
TIME...MOT...LOC 1328Z 241DEG 32KT 4202 7147 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

Frank

2 follow-up statements

396 
WWUS51 KBOX 281403
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
1003 AM EDT Tue Sep 28 2021

MAC005-017-021-025-027-RIC007-281430-
/O.CON.KBOX.SV.W.0118.000000T0000Z-210928T1430Z/
Suffolk MA-Norfolk MA-Worcester MA-Middlesex MA-Bristol MA-
Providence RI-
1003 AM EDT Tue Sep 28 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1030 AM EDT
FOR SOUTHWESTERN SUFFOLK...NORFOLK...SOUTHEASTERN WORCESTER...
SOUTHEASTERN MIDDLESEX...NORTHWESTERN BRISTOL AND NORTHEASTERN
PROVIDENCE COUNTIES...

At 1002 AM EDT, a severe thunderstorm was located over Holbrook, or
near Randolph, moving east at 40 mph.

HAZARD...Quarter size hail.

SOURCE...Trained weather spotters reported penny sized hail in 
         Cumberland Rhode Island at 940 am.

IMPACT...Minor hail damage to vehicles is possible.

Locations impacted include...
Boston, Worcester, Quincy, Newton, Framingham, Waltham, Brookline,
Weymouth, Arlington, Woonsocket, Braintree, Shrewsbury, Cumberland,
Natick, Randolph, Watertown, Franklin, Lexington, Needham and North
Attleborough.

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 4214 7097 4210 7108 4202 7107 4186 7156
      4222 7183 4243 7120
TIME...MOT...LOC 1402Z 251DEG 40KT 4215 7099 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

Frank

841 
WWUS51 KBOX 281424
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
1024 AM EDT Tue Sep 28 2021

MAC005-017-021-025-027-RIC007-281432-
/O.EXP.KBOX.SV.W.0118.000000T0000Z-210928T1430Z/
Suffolk MA-Norfolk MA-Worcester MA-Middlesex MA-Bristol MA-
Providence RI-
1024 AM EDT Tue Sep 28 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN SUFFOLK...
NORFOLK...SOUTHEASTERN WORCESTER...SOUTHEASTERN MIDDLESEX...
NORTHWESTERN BRISTOL AND NORTHEASTERN PROVIDENCE COUNTIES WILL EXPIRE
AT 1030 AM EDT...
        
Additional thunderstorms with heavy rain, small hail and gusty winds 
will continue to impact this region over the next hour. However, the 
core of the strongest storm has exited the region. Therefore, the 
warning will be allowed to expire.  However small hail, gusty winds 
and heavy rain are still possible with this thunderstorm.

LAT...LON 4214 7097 4210 7108 4202 7107 4186 7156
      4222 7183 4243 7120
TIME...MOT...LOC 1422Z 241DEG 32KT 4222 7082 

$$

Frank

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 28, 10:02 AM EDT	Severe Thunderstorm Warning	BOX	Middlesex, Norfolk, Plymouth, Suffolk	43 min
Sep 28, 10:06 AM EDT	Special Marine Warning	BOX		54 min
Sep 28, 11:18 AM EDT	Special Weather Statement	BOX	Bristol	42 min
Sep 28, 11:42 AM EDT	Special Marine Warning	BOX		48 min
Sep 28, 1:58 PM EDT	Special Marine Warning	BOX		47 min
Sep 28, 2:07 PM EDT	Severe Thunderstorm Warning	BOX	Barnstable, Bristol, Dukes, Plymouth	53 min
Sep 28, 2:30 PM EDT	Special Marine Warning	BOX		45 min
Sep 28, 2:58 PM EDT	Special Weather Statement	BOX	Barnstable	47 min
Sep 28, 3:25 PM EDT	Small Craft Advisory	BOX		28 hr
Sep 28, 3:29 PM EDT	Special Marine Warning	BOX		46 min
Sep 28, 9:11 AM EDT	Special Weather Statement	BOX	Providence	49 min
Sep 28, 10:50 AM EDT	Special Weather Statement	BOX	Providence	40 min
Sep 28, 1:36 PM EDT	Special Weather Statement	BOX	Newport, Washington	39 min

Nearby

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