Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 3, NWS Boston/Norton, MA

May 26, 2021Franklin County, Middlesex County, Worcester County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at May 26, 2021, 6:13 PM EDT for Franklin County, Middlesex County, Worcester County, Massachusetts. It was in force for 62 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
May 26, 2021, 6:13 PM EDT (22:13 UTC)
Expired
May 26, 2021, 7:15 PM EDT
In force
62 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Franklin County, MA, Middlesex County, MA, Worcester County, MA

The radar

The Boston radar (KBOX), 101 km from the middle of the area, began a volume at 22:15 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.

IssuedProductOfficeLasted
May 26, 3:56 PM EDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Albany, NY (KALY), launched 12:00Z, 10.2 hours before the alert went out and 153 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, Albany, NY at 12:00Z on 2021-05-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 6 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, Albany, NY at 12:00Z on 2021-05-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 149 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
6 J/kg
Mixed-layer CIN
-291 J/kg
Mixed-layer LCL
1196 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
149 m²/s²
0-3 km storm-relative helicity
137 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

411 
WUUS51 KBOX 262213
SVRBOX
MAC011-017-027-262315-
/O.NEW.KBOX.SV.W.0003.210526T2213Z-210526T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
613 PM EDT Wed May 26 2021

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Northern Worcester County in central Massachusetts...
  Northwestern Middlesex County in northeastern Massachusetts...
  Northeastern Franklin County in western Massachusetts...

* Until 715 PM EDT.

* At 613 PM EDT, severe thunderstorms were located along a line
  extending from near Sharon to near Winchendon to near New Salem,
  moving east at 40 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Leominster, Fitchburg, Orange, Deerfield, Westford, Gardner, Athol,
  Pepperell, Tyngsborough, Groton, Winchendon, Lunenburg, Townsend,
  Montague, Lancaster, Templeton, Sterling, Ayer, Westminster and
  Shirley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4269 7138 4248 7166 4251 7259 4269 7240
      4273 7234
TIME...MOT...LOC 2213Z 264DEG 37KT 4281 7199 4265 7211 4251 7233 

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

BL
2 follow-up statements
833 
WWUS51 KBOX 262231
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
631 PM EDT Wed May 26 2021

MAC011-017-027-262315-
/O.CON.KBOX.SV.W.0003.000000T0000Z-210526T2315Z/
Worcester MA-Middlesex MA-Franklin MA-
631 PM EDT Wed May 26 2021

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

At 631 PM EDT, severe thunderstorms were located along a line
extending from Wilton to near Ashby to near Templeton, moving east at
35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Leominster, Fitchburg, Orange, Westford, Gardner, Athol, Pepperell,
Tyngsborough, Groton, Winchendon, Lunenburg, Townsend, Lancaster,
Templeton, Sterling, Ayer, Westminster, Shirley, Harvard and
Ashburnham.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4269 7138 4248 7166 4251 7244 4264 7233
      4273 7225
TIME...MOT...LOC 2231Z 271DEG 32KT 4284 7176 4268 7188 4254 7210 

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

BL
561 
WWUS51 KBOX 262247
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
647 PM EDT Wed May 26 2021

MAC011-017-027-262315-
/O.CON.KBOX.SV.W.0003.000000T0000Z-210526T2315Z/
Worcester MA-Middlesex MA-Franklin MA-
647 PM EDT Wed May 26 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM EDT
FOR NORTHERN WORCESTER...NORTHWESTERN MIDDLESEX AND SOUTHEASTERN
FRANKLIN COUNTIES...

At 646 PM EDT, severe thunderstorms were located along a line
extending from Amherst to near Townsend to Westminster, moving east
at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Leominster, Fitchburg, Westford, Gardner, Athol, Pepperell,
Tyngsborough, Groton, Winchendon, Lunenburg, Townsend, Lancaster,
Templeton, Ayer, Westminster, Shirley, Harvard, Ashburnham,
Hubbardston and Princeton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4269 7138 4248 7166 4251 7230 4263 7214
      4272 7201
TIME...MOT...LOC 2246Z 268DEG 33KT 4286 7160 4270 7172 4256 7194 

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

BL

The office that day

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

IssuedProductOfficeCountiesLasted
May 25, 10:05 PM EDTSmall Craft AdvisoryBOX12 hr
May 26, 9:51 AM EDTSmall Craft AdvisoryBOX21 hr
May 26, 5:03 PM EDTSpecial Weather StatementBOXFranklin27 min
May 26, 5:30 PM EDTSpecial Weather StatementBOXFranklin45 min
May 26, 5:47 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampshire, Worcester58 min
May 26, 6:39 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire, Worcester66 min
May 26, 7:05 PM EDTSevere Thunderstorm WarningBOXHampden55 min
May 26, 7:15 PM EDTSpecial Weather StatementBOXEssex, Middlesex45 min
May 26, 7:21 PM EDTSpecial Marine WarningBOX54 min
May 26, 7:45 PM EDTSevere Thunderstorm WarningBOXHampden, Hampshire, Worcester60 min

Nearby

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