Alert archive / Massachusetts / Tornado Warnings in 2021

Tornado Warning 3, NWS Boston/Norton, MA

August 19, 2021Essex County, Middlesex County, Suffolk County, Massachusetts

NWS Boston/Norton, MA issued this tornado warning at Aug 19, 2021, 12:49 PM EDT for Essex County, Middlesex County, Suffolk County, Massachusetts. It was in force for 39 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 19, 2021, 12:49 PM EDT (16:49 UTC)
Expired
Aug 19, 2021, 1:28 PM EDT
In force
39 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

Counties Essex County, MA, Middlesex County, MA, Suffolk County, MA

The radar

The Boston radar (KBOX), 61 km from the middle of the area, began a volume at 16:51 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.

The nearest sounding before it

Gray, ME (KGYX), launched 12:00Z, 4.8 hours before the alert went out and 166 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 2021-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 110 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 2021-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 36 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
110 J/kg
Mixed-layer CIN
-40 J/kg
Mixed-layer LCL
884 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
36 m²/s²
0-3 km storm-relative helicity
68 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

398 
WFUS51 KBOX 191649
TORBOX
MAC009-017-025-191745-
/O.NEW.KBOX.TO.W.0003.210819T1649Z-210819T1745Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Boston/Norton MA
1249 PM EDT Thu Aug 19 2021

The National Weather Service in Boston/Norton has issued a

* Tornado Warning for...
  North central Suffolk County in eastern Massachusetts...
  South central Essex County in northeastern Massachusetts...
  East central Middlesex County in northeastern Massachusetts...

* Until 145 PM EDT.
    
* At 1249 PM EDT, a severe thunderstorm capable of producing a
  tornado was located over Revere, moving northeast at 15 mph.

  HAZARD...Tornado.

  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.

* This dangerous storm will be near...
  Lynn and Nahant around 105 PM EDT.
  Swampscott around 120 PM EDT.
  Salem around 125 PM EDT.
  Marblehead around 130 PM EDT.
  Beverly around 145 PM EDT.

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 4257 7080 4253 7078 4255 7082 4254 7090
      4254 7087 4250 7089 4252 7085 4250 7085
      4246 7094 4242 7091 4245 7094 4245 7097
      4241 7099 4237 7097 4237 7099 4238 7101
      4235 7099 4245 7114 4262 7086
TIME...MOT...LOC 1649Z 240DEG 13KT 4242 7102 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

Chai
2 follow-up statements
506 
WWUS51 KBOX 191711
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
111 PM EDT Thu Aug 19 2021

MAC025-191721-
/O.CAN.KBOX.TO.W.0003.000000T0000Z-210819T1745Z/
Suffolk MA-
111 PM EDT Thu Aug 19 2021

...THE TORNADO WARNING FOR NORTH CENTRAL SUFFOLK COUNTY IS
CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled.

LAT...LON 4257 7080 4253 7078 4255 7082 4254 7090
      4254 7087 4251 7089 4252 7085 4250 7085
      4249 7094 4250 7106 4262 7086
TIME...MOT...LOC 1711Z 240DEG 13KT 4246 7093 

$$

MAC009-017-191745-
/O.CON.KBOX.TO.W.0003.000000T0000Z-210819T1745Z/
Essex MA-Middlesex MA-
111 PM EDT Thu Aug 19 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 145 PM EDT FOR SOUTH
CENTRAL ESSEX AND EASTERN MIDDLESEX COUNTIES...
    
At 111 PM EDT, a severe thunderstorm capable of producing a tornado
was located over Swampscott, or over Lynn, moving northeast at 15
mph.

HAZARD...Tornado.

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.

This dangerous storm will be near...
  Salem around 125 PM EDT.
  Marblehead around 130 PM EDT.
  Beverly around 150 PM EDT.

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 4257 7080 4253 7078 4255 7082 4254 7090
      4254 7087 4251 7089 4252 7085 4250 7085
      4249 7094 4250 7106 4262 7086
TIME...MOT...LOC 1711Z 240DEG 13KT 4246 7093 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

Chai
999 
WWUS51 KBOX 191728
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
128 PM EDT Thu Aug 19 2021

MAC009-017-191738-
/O.CAN.KBOX.TO.W.0003.000000T0000Z-210819T1745Z/
Essex MA-Middlesex MA-
128 PM EDT Thu Aug 19 2021

...THE TORNADO WARNING FOR SOUTH CENTRAL ESSEX AND EASTERN MIDDLESEX
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.  However heavy rain is still possible with this
thunderstorm.

LAT...LON 4257 7080 4253 7078 4255 7082 4254 7090
      4254 7087 4251 7089 4252 7085 4250 7085
      4249 7094 4250 7106 4262 7086
TIME...MOT...LOC 1727Z 240DEG 13KT 4249 7086 

$$

Chai

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 19, 8:14 AM EDTFlash Flood WarningBOXHampden, Worcester3 hr
Aug 19, 9:18 AM EDTFlash Flood WarningBOXHampden, Hampshire, Worcester3 hr
Aug 19, 10:14 AM EDTSevere Thunderstorm WarningBOXMiddlesex, Worcester44 min
Aug 19, 10:21 AM EDTTornado WarningBOXMiddlesex, Worcester29 min
Aug 19, 10:46 AM EDTFlash Flood WarningBOXEssex, Middlesex, Norfolk, Suffolk, Worcester3 hr
Aug 19, 11:36 AM EDTSevere Thunderstorm WarningBOXEssex, Middlesex, Norfolk, Suffolk, Worcester54 min
Aug 19, 11:40 AM EDTFlash Flood WarningBOXEssex, Middlesex3 hr
Aug 19, 12:32 PM EDTSevere Thunderstorm WarningBOXEssex, Middlesex, Norfolk, Suffolk58 min
Aug 19, 12:33 PM EDTSpecial Marine WarningBOX57 min
Aug 19, 1:18 PM EDTTornado WarningBOXMiddlesex, Worcester27 min
Aug 19, 1:37 PM EDTSpecial Weather StatementBOXEssex38 min
Aug 19, 1:38 PM EDTSpecial Marine WarningBOX67 min
Aug 19, 1:46 PM EDTSpecial Weather StatementBOXBarnstable59 min
Aug 19, 1:48 PM EDTSpecial Marine WarningBOX57 min
Aug 19, 1:54 PM EDTSpecial Weather StatementBOXMiddlesex51 min
Aug 19, 2:23 PM EDTSevere Thunderstorm WarningBOXMiddlesex37 min

Nearby

Tornado Warnings in Massachusetts, 2021Every tornado warning in 2021Tornadoes 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.