Alert archive / Massachusetts / Tornado Warnings in 2021

Tornado Warning 5, NWS Boston/Norton, MA

August 23, 2021Middlesex County, Worcester County, Massachusetts

NWS Boston/Norton, MA issued this tornado warning at Aug 23, 2021, 11:45 AM EDT for Middlesex County, Worcester County, Massachusetts. It was in force for 45 min. 2 reports 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 23, 2021, 11:45 AM EDT (15:45 UTC)
Expired: Aug 23, 2021, 12:30 PM EDT
In force: 45 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.0 in

Counties Middlesex County, MA, Worcester County, MA

The radar

The Boston radar (KBOX), 60 km from the middle of the area, began a volume at 15:45 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
Aug 23, 11:45 AM EDT	TORNADO	3 Sw Marlborough, MA	SPOTTER WAS WATCHING TORNADO AT THE TIME OF THE CALL.
Aug 23, 12:30 PM EDT	TORNADO	2 E Bolton, MA	NWS NORTON SURVEY TEAM CONFIRMED AN EF0 TORNADO BETWEEN 175 AND 198 MAIN ST IN BOLTON. THIS CAUSED MINOR DAMAGE CONSISTING OF TREES KNOCKED DOWN INTO POWERLINE WIRES AND A LARGE TREE BRANCH THAT WAS RIPPED FROM ANOTHER TREE. THE TORNADO TRAVELED A TENTH OF A M

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Albany, NY (KALY), launched 12:00Z, 3.8 hours before the alert went out and 186 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: 40 J/kg
Mixed-layer CIN: -54 J/kg
Mixed-layer LCL: 666 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 180 m²/s²
0-3 km storm-relative helicity: 154 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

479 
WFUS51 KBOX 231545
TORBOX
MAC017-027-231630-
/O.NEW.KBOX.TO.W.0005.210823T1545Z-210823T1630Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Boston/Norton MA
1145 AM EDT Mon Aug 23 2021

The National Weather Service in Boston/Norton has issued a

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

* Until 1230 PM EDT.

* At 1140 AM EDT, a thunderstorm capable of producing a tornado was 
  located over Marlborough, moving north at 15 mph.

  HAZARD...Tornado.

  SOURCE...Weather spotters reported funnel.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* Locations impacted include...
  Marlborough, Hudson, Westborough, Northborough, Clinton,
  Southborough, Lancaster, Sterling, Stow, Harvard, Boxborough,
  Bolton, Boylston and Berlin.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

Motorists should not take shelter under highway overpasses. If you
cannot safely drive away from the tornado, as a last resort, either
park your vehicle and stay put, or abandon your vehicle and lie down
in a low lying area and protect yourself from flying debris.

&&

LAT...LON 4231 7156 4229 7160 4245 7174 4249 7155
TIME...MOT...LOC 1540Z 174DEG 12KT 4232 7158 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...0.00 IN

$$

Gaucher

1 follow-up statement

407 
WWUS51 KBOX 231607
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
1207 PM EDT Mon Aug 23 2021

MAC017-027-231630-
/O.CON.KBOX.TO.W.0005.000000T0000Z-210823T1630Z/
Worcester MA-Middlesex MA-
1207 PM EDT Mon Aug 23 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1230 PM EDT FOR EAST
CENTRAL WORCESTER AND CENTRAL MIDDLESEX COUNTIES...
    
At 1206 PM EDT, a confirmed tornado was located over Berlin, or near 
Marlborough, moving north at 15 mph. This storm has had a history of 
producing a brief tornado and could continue to produce brief 
tornadoes.

HAZARD...Damaging tornado.

SOURCE...Weather spotters confirmed tornado. At 1145 AM a tornado 
         was reported west of I-495 in Marlborough. 

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

Locations impacted include...
Marlborough, Hudson, Northborough, Clinton, Lancaster, Sterling,
Harvard, Boxborough, Bolton, Boylston and Berlin.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. TAKE COVER NOW! Move to a
basement or an interior room on the lowest floor of a sturdy
building. Avoid windows. If you are outdoors, in a mobile home, or in
a vehicle, move to the closest substantial shelter and protect
yourself from flying debris.

Motorists should not take shelter under highway overpasses. If you
cannot safely drive away from the tornado, as a last resort, either
park your vehicle and stay put, or abandon your vehicle and lie down
in a low lying area and protect yourself from flying debris.

&&

LAT...LON 4232 7156 4231 7162 4245 7174 4249 7155
TIME...MOT...LOC 1603Z 174DEG 12KT 4240 7159 

TORNADO...OBSERVED
MAX HAIL SIZE...0.00 IN

$$

Gaucher

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 23, 11:30 AM EDT	Special Weather Statement	BOX	Middlesex	45 min
Aug 23, 12:26 PM EDT	Tornado Warning	BOX	Middlesex, Worcester	43 min
Aug 23, 1:35 PM EDT	Tornado Warning	BOX	Middlesex, Worcester	40 min
Aug 23, 4:15 PM EDT	Special Weather Statement	BOX	Middlesex	45 min
Aug 23, 5:19 PM EDT	Special Weather Statement	BOX	Middlesex	41 min

Nearby

Tornado Warnings in Massachusetts, 2021 Every tornado warning in 2021 Tornadoes 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.