Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 102, NWS Boston/Norton, MA

August 14, 2021Barnstable County, Plymouth County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Aug 14, 2021, 12:08 PM EDT for Barnstable County, Plymouth County, Massachusetts. It was in force for 27 min. 4 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 14, 2021, 12:08 PM EDT (16:08 UTC)
Expired
Aug 14, 2021, 12:35 PM EDT
In force
27 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Barnstable County, MA, Plymouth County, MA

The radar

The Boston radar (KBOX), 57 km from the middle of the area, began a volume at 16:10 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
Aug 14, 12:15 PM EDTTSTM WND DMGBourne, MA2 LARGE LIMBS DOWN ON PURITAN ROAD AT WALL ST
Aug 14, 12:15 PM EDTTSTM WND DMGBourne, MATWO TREES DOWN ON WIRES ON SNOW CIRCLE
Aug 14, 12:20 PM EDTMARINE TSTM WIND 50Sandwich, MA
Aug 14, 12:22 PM EDTTSTM WND DMGSandwich, MAMANY LARGE BRANCHES DOWN ON SANDWICH ROAD AT BEN ABBEY DRIVE. LARGE BRANCHES WERE ALSO DOWN ON WIRES ON TYLER DRIVE.

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 4.1 hours before the alert went out and 218 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, Brookhaven, NY at 12:00Z on 2021-08-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 748 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, Brookhaven, NY at 12:00Z on 2021-08-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 18 square meters per square second.1939Sfc1 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
748 J/kg
Mixed-layer CIN
-93 J/kg
Mixed-layer LCL
1208 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
90 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

765 
WUUS51 KBOX 141608
SVRBOX
MAC001-023-141715-
/O.NEW.KBOX.SV.W.0102.210814T1608Z-210814T1715Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
1208 PM EDT Sat Aug 14 2021

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Central Barnstable County in southeastern Massachusetts...
  Southeastern Plymouth County in southeastern Massachusetts...

* Until 115 PM EDT.

* At 1208 PM EDT, a severe thunderstorm was located over Bourne, or 8
  miles northeast of Marion, moving east at 25 mph.

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

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Plymouth, Barnstable, Brewster, Yarmouth, Wareham, Sandwich,
  Bourne, Dennis, Mashpee and Harwich.

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.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4166 7063 4168 7063 4166 7065 4172 7063
      4170 7062 4175 7063 4174 7066 4173 7064
      4170 7065 4170 7067 4181 7072 4186 7053
      4182 7054 4176 7047 4172 7030 4172 7035
      4171 7033 4178 7005 4168 7003
TIME...MOT...LOC 1608Z 257DEG 21KT 4176 7061 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Chai
3 follow-up statements
627 
WWUS51 KBOX 141626
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
1226 PM EDT Sat Aug 14 2021

MAC001-023-141715-
/O.CON.KBOX.SV.W.0102.000000T0000Z-210814T1715Z/
Barnstable MA-Plymouth MA-
1226 PM EDT Sat Aug 14 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 PM EDT
FOR CENTRAL BARNSTABLE AND SOUTHEASTERN PLYMOUTH COUNTIES...

At 1224 PM EDT, a severe thunderstorm was located near Sandwich, or
10 miles southeast of Plymouth, moving east at 25 mph.

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

SOURCE...Radar indicated and train spotter reported. Weather station 
         reported a sustained 40 mph wind with 50 mph gust at 
         Sandwich Marina. 

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

Locations impacted include...
Plymouth, Barnstable, Brewster, Yarmouth, Wareham, Sandwich, Bourne,
Dennis, Mashpee and Harwich.

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 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 4166 7063 4168 7063 4166 7065 4172 7063
      4170 7062 4175 7063 4174 7066 4173 7064
      4170 7065 4170 7067 4181 7072 4186 7053
      4182 7054 4176 7047 4172 7030 4172 7035
      4171 7033 4178 7005 4168 7003
TIME...MOT...LOC 1624Z 257DEG 21KT 4178 7049 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Chai
654 
WWUS51 KBOX 141628
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
1228 PM EDT Sat Aug 14 2021

MAC001-023-141715-
/O.CON.KBOX.SV.W.0102.000000T0000Z-210814T1715Z/
Barnstable MA-Plymouth MA-
1228 PM EDT Sat Aug 14 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 PM EDT
FOR CENTRAL BARNSTABLE AND SOUTHEASTERN PLYMOUTH COUNTIES...

At 1226 PM EDT, a severe thunderstorm was located near Sandwich, or
10 miles northwest of Barnstable, moving east at 25 mph.

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

SOURCE...Radar indicated and public. At 1222 PM, amateur radio 
         reported tree down on Sandwich Road at Ben Abbey Drive as 
         well as tree down on 6 Tyler Drive.

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

Locations impacted include...
Plymouth, Barnstable, Brewster, Yarmouth, Wareham, Sandwich, Bourne,
Dennis, Mashpee and Harwich.

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 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 4166 7063 4168 7063 4166 7065 4172 7063
      4170 7062 4175 7063 4174 7066 4173 7064
      4170 7065 4170 7067 4181 7072 4186 7053
      4182 7054 4176 7047 4172 7030 4172 7035
      4171 7033 4178 7005 4168 7003
TIME...MOT...LOC 1626Z 257DEG 21KT 4178 7047 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Chai
424 
WWUS51 KBOX 141635
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
1235 PM EDT Sat Aug 14 2021

MAC001-023-141645-
/O.CAN.KBOX.SV.W.0102.000000T0000Z-210814T1715Z/
Barnstable MA-Plymouth MA-
1235 PM EDT Sat Aug 14 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL BARNSTABLE AND
SOUTHEASTERN PLYMOUTH COUNTIES IS CANCELLED...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning has
been cancelled.

LAT...LON 4166 7063 4168 7063 4166 7065 4172 7063
      4170 7062 4175 7063 4174 7066 4173 7064
      4170 7065 4170 7067 4181 7072 4186 7053
      4182 7054 4176 7047 4172 7030 4172 7035
      4171 7033 4178 7005 4168 7003
TIME...MOT...LOC 1634Z 257DEG 21KT 4179 7040 

$$

Chai

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 13, 8:48 PM EDTSpecial Weather StatementBOXFranklin57 min
Aug 14, 12:04 PM EDTSpecial Weather StatementBOXBarnstable56 min
Aug 14, 12:07 PM EDTSpecial Marine WarningBOX68 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.