Alert archive / Massachusetts / Tornado Warnings in 2023

Tornado Warning 13, NWS Boston/Norton, MA

August 18, 2023Norfolk County, Plymouth County, Massachusetts

NWS Boston/Norton, MA issued this tornado warning at Aug 18, 2023, 9:45 AM EDT for Norfolk County, Plymouth County, Massachusetts. It was in force for 21 min. 3 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 18, 2023, 9:45 AM EDT (13:45 UTC)
Expired
Aug 18, 2023, 10:06 AM EDT
In force
21 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Tornado
Radar indicated
Hail
1.0 in

Counties Norfolk County, MA, Plymouth County, MA

The radar

The Boston radar (KBOX), 26 km from the middle of the area, began a volume at 13:46 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 18, 9:45 AM EDTTSTM WND DMGWeymouth, MANumerous reports of trees and wires down across the town.
Aug 18, 9:45 AM EDTTSTM WND DMGWeymouth, MANumerous trees and wires down.
Aug 18, 9:50 AM EDTTORNADOWeymouth, MAA confirmed tornado touched down in Weymouth MA. An EF-rating and path length will be determined at the completion of the Storm Survey.

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

The nearest sounding before it

Gray, ME (KGYX), launched 12:00Z, 1.8 hours before the alert went out and 202 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 2023-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 64 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 2023-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 162 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
64 J/kg
Mixed-layer CIN
-36 J/kg
Mixed-layer LCL
471 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
162 m²/s²
0-3 km storm-relative helicity
236 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

781 
WFUS51 KBOX 181345
TORBOX
MAC021-023-181445-
/O.NEW.KBOX.TO.W.0013.230818T1345Z-230818T1445Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Boston/Norton MA
945 AM EDT Fri Aug 18 2023

The National Weather Service in Boston/Norton has issued a

* Tornado Warning for...
  East central Norfolk County in eastern Massachusetts...
  Northern Plymouth County in southeastern Massachusetts...

* Until 1045 AM EDT.
    
* At 944 AM EDT, a severe thunderstorm capable of producing a tornado
  was located over Holbrook, or near Randolph, moving east at 30 mph.

  HAZARD...Tornado and quarter size hail.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* Locations impacted include...
  Brockton, Weymouth, Braintree, Randolph, Stoughton, Marshfield,
  Hingham, Canton, Scituate, Pembroke, Rockland, Abington, Whitman,
  Hanover, Holbrook, Norwell, Hanson, Cohasset, and Avon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4209 7108 4217 7111 4227 7080 4209 7064
TIME...MOT...LOC 1344Z 253DEG 25KT 4214 7101 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN

$$
Dooley
2 follow-up statements
237 
WWUS51 KBOX 181359
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
959 AM EDT Fri Aug 18 2023

MAC021-023-181445-
/O.CON.KBOX.TO.W.0013.000000T0000Z-230818T1445Z/
Norfolk MA-Plymouth MA-
959 AM EDT Fri Aug 18 2023

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1045 AM EDT FOR EASTERN
NORFOLK AND NORTHWESTERN PLYMOUTH COUNTIES...
    
At 958 AM EDT, a severe thunderstorm capable of producing a tornado
was located over Rockland, or near Weymouth, moving east at 30 mph.

HAZARD...Tornado and quarter size hail.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

Locations impacted include...
Weymouth, Braintree, Marshfield, Hingham, Scituate, Rockland,
Abington, Hanover, Holbrook, Norwell, and Cohasset.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

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

&&

LAT...LON 4214 7096 4220 7103 4227 7080 4216 7070
      4215 7070
TIME...MOT...LOC 1358Z 253DEG 25KT 4217 7089 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN

$$
Dooley
170 
WWUS51 KBOX 181406
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
1006 AM EDT Fri Aug 18 2023

MAC021-023-181415-
/O.CAN.KBOX.TO.W.0013.000000T0000Z-230818T1445Z/
Norfolk MA-Plymouth MA-
1006 AM EDT Fri Aug 18 2023

...THE TORNADO WARNING FOR EASTERN NORFOLK AND NORTHWESTERN PLYMOUTH
COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning has been cancelled.  However gusty winds and
heavy rain are still possible with this thunderstorm.

LAT...LON 4214 7096 4220 7103 4227 7080 4216 7070
      4215 7070
TIME...MOT...LOC 1404Z 253DEG 25KT 4219 7082 

$$
Dooley

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 8:05 AM EDTSevere Thunderstorm WarningBOXBristol, Middlesex, Norfolk, Worcester55 min
Aug 18, 8:26 AM EDTFlash Flood WarningBOXBristol2 hr
Aug 18, 8:35 AM EDTTornado WarningBOXBristol, Norfolk, Worcester40 min
Aug 18, 8:50 AM EDTSevere Thunderstorm WarningBOXBristol55 min
Aug 18, 8:56 AM EDTSevere Thunderstorm WarningBOXMiddlesex, Norfolk, Worcester34 min
Aug 18, 9:12 AM EDTSevere Thunderstorm WarningBOXBristol, Middlesex, Norfolk, Plymouth, Suffolk63 min
Aug 18, 9:18 AM EDTFlash Flood WarningBOXBristol, Essex, Middlesex, Norfolk, Plymouth, Suffolk and 1 more79 min
Aug 18, 9:22 AM EDTTornado WarningBOXBristol, Norfolk, Plymouth23 min
Aug 18, 9:28 AM EDTSpecial Marine WarningBOX92 min
Aug 18, 9:36 AM EDTFlash Flood WarningBOXBristol, Norfolk, Plymouth2 hr
Aug 18, 10:03 AM EDTFlash Flood WarningBOXEssex, Middlesex98 min
Aug 18, 10:19 AM EDTFlash Flood Warning Considerable damage threatBOXEssex, Middlesex84 min
Aug 18, 10:24 AM EDTSevere Thunderstorm WarningBOXEssex24 min
Aug 18, 10:25 AM EDTSpecial Marine WarningBOX65 min
Aug 18, 10:41 AM EDTSpecial Marine WarningBOX64 min
Aug 18, 10:55 AM EDTRiver Flood WarningBOXEssex17 hr
Aug 18, 3:33 PM EDTSpecial Weather StatementBOXNorfolk57 min
Aug 18, 3:57 PM EDTSpecial Marine WarningBOX63 min
Aug 18, 5:28 PM EDTSpecial Weather StatementBOXEssex62 min

Nearby

Tornado Warnings in Massachusetts, 2023Every tornado warning in 2023Tornadoes in 2023

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.