Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 94, NWS Boston/Norton, MA

July 27, 20216 counties in Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 27, 2021, 6:33 PM EDT for 6 counties in Massachusetts. It was in force for 57 min. 34 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 27, 2021, 6:33 PM EDT (22:33 UTC)
Expired
Jul 27, 2021, 7:30 PM EDT
In force
57 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Hail
0.88 in
Wind
60.0 mph

Counties Essex County, MA, Middlesex County, MA, Norfolk County, MA, Plymouth County, MA, Suffolk County, MA, Worcester County, MA

The radar

The Boston radar (KBOX), 43 km from the middle of the area, began a volume at 22:36 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 27, 6:33 PM EDTTSTM WND DMGSpencer, MATREE DOWN ON WIRES BETWEEN 73 AND 95 MCCORMICK ROAD. RELAYED BY AMATEUR RADIO.
Jul 27, 6:38 PM EDTTSTM WND DMGHolden, MATREE DOWN ON TOP OF A CAR. WIRES DOWN. RELAYED BY AMATEUR RADIO.
Jul 27, 6:38 PM EDTTSTM WND DMGWorcester, MATREE DOWN ON A CAR AT 61 BRIAR LANE. POWER LINES DOWN ON TACOMA STREET AND CLARK STREET. TREE AND WIRES DOWN BLOCKING ROAD ON QUINAPOXET LANE NEAR BERGSTROM ROAD. RELAYED BY AMATEUR RADIO.
Jul 27, 6:40 PM EDTTSTM WND DMG2 Wnw Shrewsbury, MALARGE TREE DOWNED ON MAIN AND MILL ST IN BOYLSTON.
Jul 27, 6:40 PM EDTTSTM WND DMGBoylston, MA4-5 FOOT DIAMETER TREE DOWN AT CORNER OF MAIN STREET AND PAUL TIVMAN ROAD. LARGE BRANCH DOWN AT THE CORNER OF BELAIR STREET AND MAIN STREET.
Jul 27, 6:40 PM EDTTSTM WND DMGShrewsbury, MATWO TREES DOWN ON HILLANDO DRIVE NEAR WALNUT STREET. RELAYED BY AMATEUR RADIO.
Jul 27, 6:45 PM EDTTSTM WND DMGWorcester, MATREE DOWN PARTIALLY BLOCKING ROAD AT 1222 PLEASANT STREET. RELAYED BY AMATEUR RADIO.
Jul 27, 6:48 PM EDTTSTM WND DMGNorthborough, MASIDING BLOWN OFF THE SIDE OF A HOUSE ON BRIGHAM STREEET NEAR SOUTH STREET. RELAYED BY AMATEUR RADIO.
Jul 27, 6:55 PM EDTTSTM WND DMGWestborough, MATREE AND WIRES DOWN AT 7 ARCH STREET. RELAYED BY AMATEUR RADIO.
Jul 27, 7:00 PM EDTTSTM WND DMGUpton, MATREE DOWN NEAR 8 NORTH MAIN STREET. RELAYED BY AMATEUR RADIO.
Jul 27, 7:10 PM EDTTSTM WND DMGNatick, MATREE DOWN ON A HOUSE AT 88 KENDALL LANE. RELAYED BY AMATEUR RADIO.
Jul 27, 7:18 PM EDTTSTM WND DMGWellesley, MATREE DOWN BLOACKING WALNUT STREET AT WHITTIER ROAD. RELAYED BY AMATEUR RADIO.
Jul 27, 7:18 PM EDTTSTM WND DMGWellesley, MALARGE BRANCH DOWN NEAR 33 CEDAR STREET. RELAYED BY AMATEUR RADIO.
Jul 27, 7:19 PM EDTTSTM WND DMGSherborn, MATREE DOWN ON SOUTH MAIN STREET AT BULLARD ROAD. RLEAYED BY AMATEUR RADIO.
Jul 27, 7:21 PM EDTTSTM WND DMG2 Wnw Newton, MATREE DOWN ON A CAR ON COMMONWEALTH AVE IN NEWTON
Jul 27, 7:21 PM EDTTSTM WND DMGNewton, MATREE DOWN BLOCKING THE STREET NEAR 19 PARK DRIVE. TREE DOWN ON A HOUSE AT 111 PROSPECT STREET. RELAYED BY AMATEUR RADIO.
Jul 27, 7:21 PM EDTTSTM WND DMGNewton, MATREE DOWN ON A CAR NEAR 1750 COMMONWEALTH AVE. RELAYED BY AMATEUR RADIO.
Jul 27, 7:26 PM EDTTSTM WND DMGBrighton, MABRANCHES DOWN ON THE MASS PIKE (I-90) NEAR THE NEWTON LINE.
Jul 27, 7:26 PM EDTTSTM WND DMGWaltham, MATREE AND WIRES DOWN AT 33 BROWN STREET. RELAYED BY AMATEUR RADIO.
Jul 27, 7:27 PM EDTTSTM WND DMG1 Nw Allston, MATREE DOWN ON A CAR ON EVERETT ST
Jul 27, 7:27 PM EDTTSTM WND DMG1 Wnw Dover, MATREE DOWN ON HAVEN ST AND CHURCH ST INTESECTION IN DOVER. RELAYED BY AMATEUR RADIO.
Jul 27, 7:27 PM EDTTSTM WND DMG1 Wsw East Boston, MATREE DOWN NEAR THE CHANNEL 7 NEWS STATION ON BULLFINCH PLACE.
Jul 27, 7:27 PM EDTTSTM WND DMGBoston, MATREE DOWN ACROSS CRICUIT DRIVE; POWER LINES DOWN ON NEPONSET VALLEY PARKWAY, TWO TREES DOWN ON 400 BLOCK OF MARLBORO STREET, LARGE BRANCH DOWN ON CAR ON 1300 BLOCK OF COMMONWEALTH AVE, LARGE TREE DOWN ON CARS ON JAMAICA STREET, LARGE BRANCH ON WIRES ON CORMAN
Jul 27, 7:27 PM EDTTSTM WND DMGBrighton, MAPOWER LINES DOWN ON CUMMINGS ROAD. RELAYED BY AMATEUR RADIO.
Jul 27, 7:27 PM EDTTSTM WND DMGCambridge, MATREE DOWN ON FRESH POND PARKWAY. TREE DOWN AND BLOCKING ANTRIM STREET. RELAYED BY AMATEUR RADIO.
Jul 27, 7:27 PM EDTTSTM WND DMGDorchester, MAPOWER LINES DOWN ON WALES STREET. RELAYED BY AMATEUR RADIO.
Jul 27, 7:27 PM EDTTSTM WND DMGNewton, MATREE DOWN ON ADAMS STREET AT WILTSHIRE ROAD. RELAYED BY AMATEUR RADIO.
Jul 27, 7:27 PM EDTTSTM WND DMGRoslindale, MALARGE BRANCH DOWN ON LOWER SOUTH STREET NEXT TO ARNOLD STREET. RELAYED BY AMATEUR RADIO.
Jul 27, 7:30 PM EDTTSTM WND DMGSomerville, MATREE DOWN ON HOUSE IN THE AREA OF 101 PEARL STREET. SMALL TREE DOWN ON CAR ON BONAIR STREET. RELAYED BY AMATEUR RADIO.
Jul 27, 7:34 PM EDTTSTM WND DMGMedford, MATREE DOWN IN THE ROADWAY ON CRUSHING STREET. TREE DOWN ON CAR ON CLINTON STREET. TREE DOWN ON CARBERRY STREET. TREE AND WIRES DOWN AND LEANING ON A HOUSE ON GOVERNORS AVE. RELAYED BY AMATEUR RADIO.
Jul 27, 7:36 PM EDTTSTM WND DMG1 S Brighton, MATREE DOWN ON ENGLEWOOD AVE IN BRIGHTON. RELAYED BY AMATEUR RADIO.
Jul 27, 7:40 PM EDTTSTM WND DMG1 Ssw Quincy, MATREE DOWN ON 49 NELSON ST IN QUINCY. RELAYED BY AMATEUR RADIO
Jul 27, 7:40 PM EDTTSTM WND DMGQuincy, MATREE DOWN ON CAR ON EVANS AND WEST SQUANTUM STREETS, PERSON TRAPPED AND EXTRICATED, UNINJURED. RELAYED BY AMATEUR RADIO.
Jul 27, 7:40 PM EDTTSTM WND DMGQuincy, MATREE DOWN BLOCKING ROAD ON FURNACE BROOK PKWY IN QUINCY. RELAYED BY AMATEUR RADIO.

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

The watch it was issued in

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

IssuedProductOfficeLasted
Jul 27, 2:47 PM EDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Gray, ME (KGYX), launched 12:00Z, 10.6 hours before the alert went out and 185 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, Gray, ME at 12:00Z on 2021-07-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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, Gray, ME at 12:00Z on 2021-07-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 square meters per square second.19395878Sfc1 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
1 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1443 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
24 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

012 
WUUS51 KBOX 272233
SVRBOX
MAC009-017-021-023-025-027-272330-
/O.NEW.KBOX.SV.W.0094.210727T2233Z-210727T2330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
633 PM EDT Tue Jul 27 2021

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Suffolk County in eastern Massachusetts...
  Norfolk County in eastern Massachusetts...
  South central Essex County in northeastern Massachusetts...
  Eastern Worcester County in central Massachusetts...
  Middlesex County in northeastern Massachusetts...
  Northwestern Plymouth County in southeastern Massachusetts...

* Until 730 PM EDT.

* At 632 PM EDT, severe thunderstorms were located along a line
  extending from near Fitchburg to Leicester, moving east at 40 mph.

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

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Boston, Worcester, Cambridge, Brockton, Quincy, Newton, Somerville,
  Framingham, Waltham, Malden, Brookline, Medford, Weymouth, Revere,
  Arlington, Everett, Leominster, Fitchburg, Billerica and
  Marlborough.

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 these storms. 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 4259 7104 4247 7105 4244 7096 4241 7099
      4236 7096 4238 7105 4233 7101 4230 7105
      4229 7102 4232 7101 4228 7102 4226 7097
      4232 7093 4226 7096 4223 7091 4215 7093
      4205 7119 4215 7208 4264 7183
TIME...MOT...LOC 2232Z 279DEG 34KT 4256 7179 4221 7192 

HAIL...0.88IN
WIND...60MPH
 
$$

Loconto/Gaucher
3 follow-up statements
782 
WWUS51 KBOX 272257
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
657 PM EDT Tue Jul 27 2021

MAC009-017-021-023-025-027-272330-
/O.CON.KBOX.SV.W.0094.000000T0000Z-210727T2330Z/
Suffolk MA-Norfolk MA-Essex MA-Worcester MA-Middlesex MA-Plymouth MA-
657 PM EDT Tue Jul 27 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM EDT
FOR SUFFOLK...NORFOLK...SOUTH CENTRAL ESSEX...EASTERN WORCESTER...
MIDDLESEX AND NORTHWESTERN PLYMOUTH COUNTIES...

At 656 PM EDT, severe thunderstorms were located along a line
extending from Ayer to Auburn, moving east at 35 mph.

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

SOURCE...Trained weather spotters. Multiple trees and powerlines 
         been downed in Worcester from these severe thunderstorms. 
         In addition, a 52 mph wind gust was reported at Worcester 
         Airport at 633 PM. 

IMPACT...Expect wind damage to trees and power lines. Minor hail 
         damage to vehicles is possible.

Locations impacted include...
Boston, Worcester, Cambridge, Brockton, Quincy, Newton, Somerville,
Framingham, Waltham, Malden, Brookline, Medford, Weymouth, Revere,
Arlington, Everett, Leominster, Fitchburg, Billerica and Marlborough.

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 these storms.
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 these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4259 7104 4247 7105 4244 7096 4241 7099
      4236 7096 4238 7105 4233 7101 4230 7105
      4229 7102 4232 7101 4228 7102 4226 7097
      4232 7093 4226 7096 4223 7091 4215 7093
      4205 7119 4215 7208 4264 7183
TIME...MOT...LOC 2256Z 279DEG 32KT 4254 7159 4217 7184 

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

Loconto/Gaucher
770 
WWUS51 KBOX 272314
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
714 PM EDT Tue Jul 27 2021

MAC009-017-021-023-025-027-272330-
/O.CON.KBOX.SV.W.0094.000000T0000Z-210727T2330Z/
Suffolk MA-Norfolk MA-Essex MA-Worcester MA-Middlesex MA-Plymouth MA-
714 PM EDT Tue Jul 27 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM EDT
FOR SUFFOLK...NORFOLK...SOUTH CENTRAL ESSEX...SOUTHEASTERN
WORCESTER...MIDDLESEX AND NORTHWESTERN PLYMOUTH COUNTIES...

At 713 PM EDT, severe thunderstorms were located along a line
extending from Littleton to near Sutton, moving east at 40 mph.

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

SOURCE...Trained weather spotters. Multiple trees and powerlines 
         have been downed in Worcester and Westborough from these 
         severe thunderstorms. 

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

Locations impacted include...
Boston, Worcester, Cambridge, Brockton, Quincy, Newton, Somerville,
Framingham, Waltham, Malden, Brookline, Medford, Weymouth, Revere,
Arlington, Everett, Billerica, Marlborough, Woburn and Braintree.

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 these storms.
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 these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4259 7104 4247 7105 4244 7096 4241 7099
      4236 7096 4238 7105 4233 7101 4230 7105
      4229 7102 4232 7101 4228 7102 4226 7097
      4232 7093 4226 7096 4223 7091 4215 7093
      4205 7119 4215 7208 4261 7138
TIME...MOT...LOC 2313Z 279DEG 34KT 4253 7146 4216 7171 

HAIL...0.88IN
WIND...60MPH
 
$$

Loconto
996 
WWUS51 KBOX 272328
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
728 PM EDT Tue Jul 27 2021

MAC009-017-021-023-025-027-272338-
/O.EXP.KBOX.SV.W.0094.000000T0000Z-210727T2330Z/
Suffolk MA-Norfolk MA-Essex MA-Worcester MA-Middlesex MA-Plymouth MA-
728 PM EDT Tue Jul 27 2021

...THE SEVERE THUNDERSTORM WARNING FOR SUFFOLK...NORFOLK...SOUTH
CENTRAL ESSEX...SOUTHEASTERN WORCESTER...MIDDLESEX AND NORTHWESTERN
PLYMOUTH COUNTIES WILL EXPIRE AT 730 PM EDT...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.  However gusty
winds are still possible with these thunderstorms.

A Severe Thunderstorm Watch remains in effect until 1000 PM EDT for
eastern, central, southeastern and northeastern Massachusetts.

LAT...LON 4259 7104 4247 7105 4244 7096 4241 7099
      4236 7096 4238 7105 4233 7101 4230 7105
      4229 7102 4232 7101 4228 7102 4226 7097
      4232 7093 4226 7096 4223 7091 4215 7093
      4205 7119 4215 7208 4261 7138
TIME...MOT...LOC 2328Z 279DEG 34KT 4251 7127 4214 7153 

$$

Loconto/Gaucher

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 27, 4:48 PM EDTSpecial Weather StatementBOXFranklin27 min
Jul 27, 4:59 PM EDTSpecial Weather StatementBOXHampshire31 min
Jul 27, 5:04 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire56 min
Jul 27, 5:15 PM EDTSpecial Weather StatementBOXFranklin30 min
Jul 27, 5:34 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire56 min
Jul 27, 6:01 PM EDTSpecial Weather StatementBOXWorcester29 min
Jul 27, 6:50 PM EDTSpecial Weather StatementBOXEssex25 min
Jul 27, 6:52 PM EDTSpecial Marine WarningBOX53 min
Jul 27, 7:01 PM EDTSevere Thunderstorm WarningBOXHampden, Worcester44 min
Jul 27, 7:11 PM EDTSpecial Marine WarningBOX94 min
Jul 27, 7:26 PM EDTSevere Thunderstorm WarningBOXBristol, Essex, Middlesex, Norfolk, Plymouth, Suffolk and 1 more64 min
Jul 27, 7:39 PM EDTSpecial Marine WarningBOX66 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.