Tornadoes · United States · Massachusetts · 2021

EF0 tornado, Clinton, Massachusetts, August 19, 2021

This EF0 tornado ran 0.5 miles across Worcester County on August 19, 2021, touching down at 1:30 PM EDT and reaching 35 yards wide. It killed nobody, and did $12,000 of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mphthis tornado

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. EF186 to 110 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. EF2111 to 135 mph

    Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

  4. EF3136 to 165 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. EF4166 to 200 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. EF5over 200 mph

    Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

  7. Unrated

    The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

The record

Rating
EF0
Date
August 19, 2021
Touchdown
1:30 PM EDT (17:30 UTC)
Lifted
1:31 PM EDT (17:31 UTC)
On the ground
1 minutes
Path length
0.5 miles (0.9 km)
Path width
35 yards (32 m)
Deaths
0
Injuries
0
Property damage
$12,000
County
Worcester County
Touchdown point
42.415, -71.679
Lift-off point
42.421, -71.673
Record number
2108191130-01

What the Weather Service recorded

The remnants of Tropical Storm Fred moved across Southern New England producing heavy rain, gusty winds, and two tornadoes - one that moved from northeast Connecticut into Worcester County and another in central Worcester County.

A weak tornado touched down in the early afternoon in the town of |Clinton in eastern Worcester County, Massachusetts. A NWS |meteorologist conducted a storm survey following tips from amateur |radio operators and the local fire chief. The following information |summarizes all of the reports. ||The tornado touched down near the intersection of Cedar Street and |Church Street. It tracked northeastward, impacting Benefit Street, |Haskell Avenue, and Water Street at Beech Street. This is a path |length of 0.5 miles. The approximate path width was 35 yards. Damage |photos led to estimates of maximum wind speeds of 75 to 80 mph, |which is an EF0 on the Enhanced Fujita Scale. The time, based on |radar and eyewitness accounts, was from 130 PM to 131 PM EDT. ||A row of trees was snapped and downed in a convergent fashion near |Church Street at Cedar Street. Other trees were downed on Haskell |Avenue at Beech Street. The fire chief relayed that multiple |residents witnessed a tornado touchdown on Water Street, where |extensive damage was observed.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

12 minutes of warning. NWS BOX issued a tornado warning for this county at 17:18 UTC, 12 minutes before the tornado touched down, in force until 17:45 UTC.

Issued (UTC)ExpiredProductOffice
12:14 UTC15:15 UTCFlash Flood WarningBOX
13:18 UTC16:15 UTCFlash Flood WarningBOX
14:14 UTC14:58 UTCSevere Thunderstorm WarningBOX
14:21 UTC14:50 UTCTornado WarningBOX
14:46 UTC17:45 UTCFlash Flood WarningBOX
15:36 UTC16:14 UTCSevere Thunderstorm WarningBOX
17:18 UTC17:45 UTCTornado WarningBOX

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The forecast that day

The Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 16:44 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The air that afternoon

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Albany, NY (KALY), 12:00Z

5.5 hours before the tornado, 179 km from the path. August 19, 2021.

Skew-T log-pSkew-T log-p diagram, Albany, NY at 12:00Z on 2021-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 5 joules per kilogram, CIN -104, lifted condensation level 523 meters above ground. Wind barbs in knots down the right edge.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. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Albany, NY at 12:00Z on 2021-08-19The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 194 square meters per square second, 0 to 6 km bulk shear 11 knots.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. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
5 J/kg
Mixed-layer CIN
-104 J/kg
Surface CAPE
50 J/kg
Mixed-layer LCL
523 m above ground
0-6 km bulk shear
11 kt
0-1 km bulk shear
29 kt
0-1 km storm-relative helicity
194 m²/s²
0-3 km storm-relative helicity
350 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3
0-3 km lapse rate
4.5 K/km

Open this sounding in Storm Lab

Albany, NY (KALY), 00:00Z

6.5 hours after it, 179 km from the path. August 20, 2021.

Skew-T log-pSkew-T log-p diagram, Albany, NY at 00:00Z on 2021-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 24 joules per kilogram, CIN -162, lifted condensation level 532 meters above ground. Wind barbs in knots down the right edge.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. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Albany, NY at 00:00Z on 2021-08-20The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity -103 square meters per square second, 0 to 6 km bulk shear 25 knots.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. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
24 J/kg
Mixed-layer CIN
-162 J/kg
Surface CAPE
87 J/kg
Mixed-layer LCL
532 m above ground
0-6 km bulk shear
25 kt
0-1 km bulk shear
19 kt
0-1 km storm-relative helicity
-103 m²/s²
0-3 km storm-relative helicity
-31 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.5 K/km

Open this sounding in Storm Lab

The surface observations

Fitchburg (FIT), 16 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
15:30 UTC110° 5 kt1014.6-RA BR
15:35 UTC7371100° 3 kt1014.6-RA BR
15:40 UTC110° 4 kt1014.6-RA BR
15:42 UTC737190° 4 kt1014.6-RA
15:45 UTC100° 2 kt1014.6-RA
15:50 UTC100° 2 kt1014.2
15:52 UTC7571 3 kt1014.2
15:55 UTC110° 4 kt1014.2
16:00 UTC90° 2 kt1014.2-RA
16:05 UTC90° 4 kt1014.2-RA
16:10 UTC120° 4 kt1013.9-RA
16:10 UTC7672120° 4 kt1013.9-RA
16:15 UTC90° 2 kt1013.9
16:18 UTC7672110° 3 kt1013.9
16:20 UTC100° 4 kt1013.9-RA
16:25 UTC100° 4 kt1013.9RA BR
16:25 UTC7672100° 4 kt1013.9RA BR
16:30 UTC90° 2 kt1013.9-RA BR
16:34 UTC76730° 0 kt1013.9-RA BR
16:35 UTC0° 0 kt1013.9-RA BR
16:45 UTC80° 4 kt1013.5-RA BR
16:50 UTC70° 2 kt1013.5-RA BR
16:52 UTC7672 3 kt1013.5-RA BR
16:55 UTC70° 2 kt1013.5-RA BR
17:05 UTC0° 0 kt1013.2-RA BR
17:05 UTC76730° 0 kt1013.2-RA BR
17:10 UTC0° 0 kt1013.2-RA BR
17:11 UTC76720° 0 kt1013.2-RA BR
17:15 UTC0° 0 kt1013.2-RA BR
17:20 UTC0° 0 kt1013.2RA BR
17:23 UTC76720° 0 kt1013.2RA BR
17:25 UTC0° 0 kt1013.2RA BR
17:30 UTC320° 2 kt1013.2+RA BR
17:35 UTC310° 4 kt1012.9+RA BR
17:38 UTC7773340° 5 kt1012.9-RA BR
17:40 UTC7773350° 4 kt1012.9-RA BR
17:40 UTC350° 4 kt1012.9-RA BR
17:45 UTC350° 2 kt1012.9-RA
17:50 UTC360° 2 kt1012.9
17:52 UTC7973360° 3 kt1012.5
17:55 UTC350° 2 kt1012.5
18:00 UTC350° 5 kt1012.5
18:05 UTC0° 0 kt1012.5
18:10 UTC0° 0 kt1012.5
18:15 UTC20° 4 kt1012.5
18:20 UTC10° 4 kt1012.5
18:25 UTC40° 4 kt1012.2
18:30 UTC30° 5 kt1012.2
18:35 UTC40° 2 kt1012.2
18:40 UTC40° 4 kt1012.2-RA
18:45 UTC40° 2 kt1012.2-RA
18:50 UTC30° 2 kt1012.2-RA
18:52 UTC787340° 4 kt1011.9-RA
18:55 UTC40° 2 kt1011.9-RA
19:00 UTC0° 0 kt1012.2
19:04 UTC78730° 0 kt1012.2
19:05 UTC0° 0 kt1011.9
19:10 UTC40° 4 kt1011.9
19:19 UTC777380° 3 kt1011.9+RA BR
19:20 UTC70° 4 kt1011.5+RA BR
19:25 UTC80° 5 kt1011.5+RA BR
19:29 UTC7773 6 kt1011.9-RA BR

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Boston radar (KBOX), 68 km away, was scanning. The volume nearest the touchdown began at 17:32 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
15:38 UTCFLOODWorcesterWorcester, MAWILLIAM AT SOMERSET STREET FLOODED AND IMPASSABLE
15:42 UTCFLOODWorcesterWorcester, MAMULTIPLE FLOOD REPORTS OUT OF WORCESTER A THE FOLLOWING LOCATIONS. SOUTHBRIDGE ST MCKEON RD QUINSIGIMEOND AT LAMARTINE EAST CENTRAL UNDER I-290 BRIDGE GLENNY ST MILBROOK ST UNDER THE 190 BRIDGE ENID ST AT COMMONWEALTH.
15:45 UTCTSTM WND DMGMedfordMiddlesex, MATREE DOWN AT 900 BLOCK OF HIGHLAND AVE
16:05 UTCTSTM WND DMGMaldenMiddlesex, MALARGE TREE BRANCH DOWN AT SALEM AND BRANCH STREET.
16:42 UTCTSTM WND DMGSomervilleMiddlesex, MATREE DOWN AT 40 BLOCK OF DERBY STREET. RELAYED BY AMATEUR RADIO.
16:56 UTCFLOODSomervilleMiddlesex, MAMCGRATH HIGHWAY AT MIDDLESEX AVE FLOODED AND IMPASSABLE
17:00 UTCTSTM WND DMGLynnfieldEssex, MATREE DOWN ON POWER LINES AT HEATH CIRCLE
17:00 UTCFLOODPeabodyEssex, MAPIERMONT STREET FLOODED AND IMPASSABLE
17:23 UTCFLOODLynnEssex, MAMULTIPLE ROAD CLOSED DUE TO FLOODING ACROSS TOWN
17:30 UTCTSTM WND DMG1 E ClintonWorcester, MATREE AND WIRES DOWNED ON BEECH ST IN CLINTON. RELAYED BY AMATEUR RADIO
17:30 UTCTSTM WND DMG1 Ene ClintonWorcester, MAPOWERLINE WIRES DOWNED ON CENTENNIAL ST IN CLINTON. RELAYED BY AMATEUR RADIO
17:30 UTCTSTM WND DMGClintonWorcester, MATREE DOWN ON CEDAR ST. RELAYED BY AMATEUR RADIO
17:30 UTCTORNADOClintonWorcester, MAA NWS SURVEY CONFIRMED AN EFO TORNADO IN CLINTON, MA. MAXIMUM WINDS WERE ESTIMATED AT 80 MPH. THE PATH WIDTH WAS 35 YARDS AND THE PATH LENGTH WAS 0.5 MILES. IT BEGAN NEAR CEDAR AND CHURCH STREETS, TRAVELED NORTHEAST, AND
17:35 UTCTSTM WND DMGHarvardWorcester, MAMULTIPLE TREE DOWN ON HOUGTON LANE
17:40 UTCTSTM WND DMG2 N HarvardWorcester, MALARGE TREE DOWNED ON HOUGHTON LANE IN HARVARD. RELAYED BY AMATEUR RADIO.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2021 tornado in MassachusettsEvery tornado in Massachusetts since 1950Warnings in force in Massachusetts nowThe forecast where you are

The other tornadoes of August 19, 2021

5 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 192:38 AM EDTEF0Morris, NJ0.950
August 199:15 AM CDTEF0Northeastern Connecticut Planning Region, CT to MA4.650$25,000
August 195:07 PM MDTEF1Phillips, CO0.050$20,000
August 195:09 PM MDTEF0Phillips, CO0.025
August 195:20 PM MDTEF0Phillips, CO0.025

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.