Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 65, NWS Boston/Norton, MA

July 14, 2021Franklin County, Worcester County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 14, 2021, 4:53 PM EDT for Franklin County, Worcester County, Massachusetts. It was in force for 52 min. 6 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
Jul 14, 2021, 4:53 PM EDT (20:53 UTC)
Expired
Jul 14, 2021, 5:45 PM EDT
In force
52 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Franklin County, MA, Worcester County, MA

The radar

The Boston radar (KBOX), 126 km from the middle of the area, began a volume at 20:56 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

TimeReportWhereRemark
Jul 14, 5:23 PM EDTTSTM WND DMGNorthfield, MATREE DOWN ON PINE MEADOW ROAD NEAR THE S CURVES
Jul 14, 5:36 PM EDTHAIL 0.88Erving, MANICKEL SIZE HAIL
Jul 14, 5:40 PM EDTHAIL 1Erving, MAQUARTER SIZE HAIL
Jul 14, 5:45 PM EDTTSTM WND DMGErving, MATREE AND WIRES DOWN ON WELLS STREET AND STATE ROAD.
Jul 14, 5:45 PM EDTTSTM WND DMGGill, MATREE DOWN ON MUNNS FERRY ROAD
Jul 14, 5:50 PM EDTTSTM WND DMGWendell, MATREE AND LINES DOWN ON MONTAGUE ROAD AND MORMON HOLLOW ROAD

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, 8.9 hours before the alert went out and 121 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 2021-07-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 20 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 2021-07-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 129 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
20 J/kg
Mixed-layer CIN
-211 J/kg
Mixed-layer LCL
871 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
129 m²/s²
0-3 km storm-relative helicity
134 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

148 
WUUS51 KBOX 142053
SVRBOX
MAC011-027-142145-
/O.NEW.KBOX.SV.W.0065.210714T2053Z-210714T2145Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
453 PM EDT Wed Jul 14 2021

The National Weather Service in Boston/Norton has issued a

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

* Until 545 PM EDT.

* At 452 PM EDT, a severe thunderstorm was located over Bernardston,
  or 8 miles north of Greenfield, moving southeast at 20 mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Greenfield, Orange, Athol, Winchendon, Montague, Northfield,
  Bernardston, Shelburne, Erving, Phillipston, Colrain, Gill,
  Royalston, Petersham, New Salem, Wendell, Warwick and Leyden.

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.

&&

LAT...LON 4272 7218 4269 7208 4245 7225 4264 7273
      4273 7266
TIME...MOT...LOC 2052Z 298DEG 18KT 4273 7255 

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

RM
2 follow-up statements
448 
WWUS51 KBOX 142118
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
518 PM EDT Wed Jul 14 2021

MAC011-027-142145-
/O.CON.KBOX.SV.W.0065.000000T0000Z-210714T2145Z/
Worcester MA-Franklin MA-
518 PM EDT Wed Jul 14 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM EDT
FOR NORTHWESTERN WORCESTER AND NORTHEASTERN FRANKLIN COUNTIES...

At 517 PM EDT, a severe thunderstorm was located over Northfield, or
7 miles northwest of Orange, moving southeast at 20 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Greenfield, Orange, Athol, Winchendon, Montague, Northfield,
Bernardston, Shelburne, Erving, Phillipston, Colrain, Gill,
Royalston, Petersham, New Salem, Wendell, Warwick and Leyden.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

This storm is producing hail. SEEK SHELTER NOW inside a sturdy 
structure and stay away from windows.

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.

&&

LAT...LON 4272 7218 4269 7208 4245 7225 4264 7273
      4273 7266
TIME...MOT...LOC 2117Z 298DEG 18KT 4267 7240 

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

RM
638 
WWUS51 KBOX 142123
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
523 PM EDT Wed Jul 14 2021

MAC011-027-142145-
/O.CON.KBOX.SV.W.0065.000000T0000Z-210714T2145Z/
Worcester MA-Franklin MA-
523 PM EDT Wed Jul 14 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM EDT
FOR NORTHWESTERN WORCESTER AND NORTHEASTERN FRANKLIN COUNTIES...

At 523 PM EDT, a severe thunderstorm was located over Warwick, or
near Orange, moving southeast at 20 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Greenfield, Orange, Athol, Winchendon, Montague, Northfield,
Bernardston, Erving, Phillipston, Gill, Royalston, Petersham, New
Salem, Wendell and Warwick.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

This storm is producing pea sized to half inch hail. SEEK SHELTER 
NOW inside a sturdy structure and stay away from windows.

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 4260 7261 4272 7249 4268 7209 4245 7225
TIME...MOT...LOC 2123Z 298DEG 18KT 4266 7236 

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

RM

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 14, 12:32 AM EDTDense Fog AdvisoryBOXBarnstable, Bristol, Dukes, Essex, Middlesex, Nantucket and 4 more9 hr
Jul 14, 3:36 AM EDTSpecial Weather StatementBOXHampden, Hampshire39 min
Jul 14, 4:15 AM EDTSpecial Weather StatementBOXHampden, Hampshire45 min
Jul 14, 4:46 PM EDTSpecial Weather StatementBOXWorcester44 min
Jul 14, 5:30 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampshire, Worcester45 min
Jul 14, 6:05 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire, Worcester40 min
Jul 14, 6:38 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire, Worcester52 min
Jul 14, 7:16 PM EDTFlash Flood WarningBOXHampshire53 min
Jul 14, 7:31 PM EDTSpecial Weather StatementBOXWorcester44 min
Jul 14, 7:33 PM EDTSpecial Weather StatementBOXHampden42 min
Jul 14, 7:46 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire, Worcester26 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.