Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 61, NWS Boston/Norton, MA

July 7, 2021Middlesex County, Worcester County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 7, 2021, 6:18 PM EDT for Middlesex County, Worcester County, Massachusetts. It was in force for 36 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 7, 2021, 6:18 PM EDT (22:18 UTC)
Expired: Jul 7, 2021, 6:54 PM EDT
In force: 36 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Middlesex County, MA, Worcester County, MA

The radar

The Boston radar (KBOX), 64 km from the middle of the area, began a volume at 22:20 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 7, 2:41 PM EDT	Severe Thunderstorm Watch	SPC	10 hr

The nearest sounding before it

Albany, NY (KALY), launched 12:00Z, 10.3 hours before the alert went out and 180 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: 18 J/kg
Mixed-layer CIN: -132 J/kg
Mixed-layer LCL: 923 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 49 m²/s²
0-3 km storm-relative helicity: 64 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

776 
WUUS51 KBOX 072218
SVRBOX
MAC017-027-072315-
/O.NEW.KBOX.SV.W.0061.210707T2218Z-210707T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
618 PM EDT Wed Jul 7 2021

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  East central Worcester County in central Massachusetts...
  Central Middlesex County in northeastern Massachusetts...

* Until 715 PM EDT.

* At 617 PM EDT, a severe thunderstorm was located over West
  Boylston, or near Shrewsbury, moving east at 15 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, Framingham, Leominster, Marlborough, Shrewsbury,
  Westford, Acton, Hudson, Westborough, Concord, Sudbury, Holden,
  Northborough, Clinton, Wayland, Groton, Maynard, Southborough,
  Littleton and Lancaster.

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 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.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4224 7183 4242 7190 4261 7147 4232 7134
TIME...MOT...LOC 2217Z 254DEG 12KT 4236 7177 

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

Loconto

2 follow-up statements

608 
WWUS51 KBOX 072238
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
638 PM EDT Wed Jul 7 2021

MAC017-027-072315-
/O.CON.KBOX.SV.W.0061.000000T0000Z-210707T2315Z/
Worcester MA-Middlesex MA-
638 PM EDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM EDT
FOR EAST CENTRAL WORCESTER AND CENTRAL MIDDLESEX COUNTIES...

At 638 PM EDT, a severe thunderstorm was located over Berlin, or near
Shrewsbury, moving east at 15 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Worcester, Framingham, Leominster, Marlborough, Shrewsbury, Westford,
Acton, Hudson, Westborough, Concord, Sudbury, Northborough, Clinton,
Wayland, Groton, Maynard, Southborough, Littleton, Lancaster and
Sterling.

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.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4225 7175 4246 7182 4261 7147 4232 7134
TIME...MOT...LOC 2238Z 254DEG 12KT 4238 7168 

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

Loconto

198 
WWUS51 KBOX 072254
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
654 PM EDT Wed Jul 7 2021

MAC017-027-072301-
/O.CAN.KBOX.SV.W.0061.000000T0000Z-210707T2315Z/
Worcester MA-Middlesex MA-
654 PM EDT Wed Jul 7 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL WORCESTER AND
CENTRAL MIDDLESEX COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.  However gusty winds and
heavy rain are still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
central and northeastern Massachusetts.

LAT...LON 4225 7175 4246 7182 4261 7147 4232 7134
TIME...MOT...LOC 2242Z 254DEG 12KT 4239 7162 

$$

Loconto

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 7, 4:00 PM EDT	Severe Thunderstorm Warning	BOX	Hampden, Hampshire	60 min
Jul 7, 4:01 PM EDT	Severe Thunderstorm Warning	BOX	Franklin, Hampshire	59 min
Jul 7, 4:05 PM EDT	Special Weather Statement	BOX	Essex	40 min
Jul 7, 4:33 PM EDT	Severe Thunderstorm Warning	BOX	Essex, Middlesex	57 min
Jul 7, 5:02 PM EDT	Special Weather Statement	BOX	Worcester	43 min
Jul 7, 5:05 PM EDT	Special Marine Warning	BOX		25 min
Jul 7, 5:10 PM EDT	Tropical Storm Watch	BOX	Barnstable, Bristol, Dukes, Nantucket, Plymouth	13 hr
Jul 7, 5:21 PM EDT	Severe Thunderstorm Warning	BOX	Hampden, Hampshire, Worcester	54 min
Jul 7, 5:24 PM EDT	Special Marine Warning	BOX		66 min
Jul 7, 5:30 PM EDT	Severe Thunderstorm Warning	BOX	Hampden, Worcester	60 min
Jul 7, 6:01 PM EDT	Special Weather Statement	BOX	Worcester	44 min
Jul 7, 6:17 PM EDT	Severe Thunderstorm Warning	BOX	Bristol, Middlesex, Norfolk, Worcester	58 min
Jul 7, 6:22 PM EDT	Special Marine Warning	BOX		53 min
Jul 7, 6:59 PM EDT	Severe Thunderstorm Warning	BOX	Bristol, Middlesex, Norfolk, Plymouth, Suffolk	61 min
Jul 7, 7:18 PM EDT	Special Marine Warning	BOX		57 min
Jul 7, 7:47 PM EDT	Severe Thunderstorm Warning	BOX	Norfolk, Plymouth	25 min
Jul 7, 7:51 PM EDT	Special Marine Warning	BOX		54 min

Nearby

Severe Thunderstorm Warnings in Massachusetts, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.