Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 31, NWS Boston/Norton, MA

June 30, 2021Middlesex County, Worcester County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jun 30, 2021, 5:00 PM EDT for Middlesex County, Worcester County, Massachusetts. It was in force for 30 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: Jun 30, 2021, 5:00 PM EDT (21:00 UTC)
Expired: Jun 30, 2021, 5:30 PM EDT
In force: 30 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Middlesex County, MA, Worcester County, MA

The radar

The Boston radar (KBOX), 89 km from the middle of the area, began a volume at 21:00 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
Jun 30, 3:21 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Gray, ME (KGYX), launched 12:00Z, 9.0 hours before the alert went out and 173 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: 906 J/kg
Mixed-layer CIN: -60 J/kg
Mixed-layer LCL: 1312 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 102 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.3

Open this sounding in Storm Lab

The text

As transmitted.

610 
WUUS51 KBOX 302100
SVRBOX
MAC017-027-302200-
/O.NEW.KBOX.SV.W.0031.210630T2100Z-210630T2200Z/

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

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  North central Worcester County in central Massachusetts...
  Northwestern Middlesex County in northeastern Massachusetts...

* Until 600 PM EDT.

* At 500 PM EDT, a severe thunderstorm was located over Townsend, or
  7 miles northeast of Fitchburg, moving east at 20 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...
  Fitchburg, Pepperell, Tyngsborough, Groton, Lunenburg, Townsend,
  Dunstable and Ashby.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4270 7144 4264 7145 4263 7180 4271 7185
TIME...MOT...LOC 2100Z 259DEG 19KT 4268 7172 

HAIL...1.00IN
WIND...60MPH
 
$$

Frank

1 follow-up statement

862 
WWUS51 KBOX 302130
SVSBOX

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

MAC017-027-302140-
/O.CAN.KBOX.SV.W.0031.000000T0000Z-210630T2200Z/
Worcester MA-Middlesex MA-
530 PM EDT Wed Jun 30 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL WORCESTER AND
NORTHWESTERN MIDDLESEX COUNTIES IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
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 1000 PM EDT for
central and northeastern Massachusetts.

LAT...LON 4270 7144 4264 7145 4263 7180 4271 7185
TIME...MOT...LOC 2129Z 259DEG 19KT 4271 7150 

$$

Frank

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 30, 2:29 AM EDT	Small Craft Advisory	BOX		18 hr
Jun 30, 3:40 PM EDT	Special Weather Statement	BOX	Hampshire	65 min
Jun 30, 3:42 PM EDT	Special Weather Statement	BOX	Franklin	63 min
Jun 30, 3:48 PM EDT	Severe Thunderstorm Warning	BOX	Franklin, Hampden, Hampshire	57 min
Jun 30, 4:03 PM EDT	Severe Thunderstorm Warning	BOX	Franklin, Hampshire	57 min
Jun 30, 4:32 PM EDT	Severe Thunderstorm Warning	BOX	Franklin, Middlesex, Worcester	58 min
Jun 30, 4:39 PM EDT	Severe Thunderstorm Warning	BOX	Franklin, Hampden, Hampshire, Worcester	66 min
Jun 30, 4:45 PM EDT	Tornado Warning	BOX	Franklin, Worcester	26 min
Jun 30, 5:13 PM EDT	Severe Thunderstorm Warning	BOX	Middlesex, Worcester	62 min
Jun 30, 5:25 PM EDT	Severe Thunderstorm Warning	BOX	Essex, Middlesex	49 min
Jun 30, 5:26 PM EDT	Special Marine Warning	BOX		64 min
Jun 30, 5:29 PM EDT	Severe Thunderstorm Warning	BOX	Worcester	44 min
Jun 30, 5:43 PM EDT	Severe Thunderstorm Warning	BOX	Essex, Middlesex	51 min
Jun 30, 5:54 PM EDT	Severe Thunderstorm Warning	BOX	Middlesex, Norfolk, Suffolk, Worcester	53 min
Jun 30, 5:58 PM EDT	Special Marine Warning	BOX		62 min
Jun 30, 6:11 PM EDT	Special Weather Statement	BOX	Norfolk	49 min
Jun 30, 6:12 PM EDT	Severe Thunderstorm Warning	BOX	Middlesex, Norfolk, Plymouth, Suffolk, Worcester	47 min
Jun 30, 6:22 PM EDT	Special Marine Warning	BOX		53 min
Jun 30, 6:31 PM EDT	Special Marine Warning	BOX		59 min
Jun 30, 6:45 PM EDT	Severe Thunderstorm Warning	BOX	Hampden	60 min
Jun 30, 6:57 PM EDT	Special Marine Warning	BOX		33 min
Jun 30, 7:15 PM EDT	Severe Thunderstorm Warning	BOX	Hampden, Worcester	60 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.