Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 111, NWS Boston/Norton, MA

September 13, 2021Essex County, Middlesex County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Sep 13, 2021, 5:34 AM EDT for Essex County, Middlesex County, Massachusetts. It was in force for 31 min. 2 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: Sep 13, 2021, 5:34 AM EDT (09:34 UTC)
Expired: Sep 13, 2021, 6:05 AM EDT
In force: 31 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Essex County, MA, Middlesex County, MA

The radar

The Boston radar (KBOX), 77 km from the middle of the area, began a volume at 09:33 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

Time	Report	Where	Remark
Sep 13, 5:44 AM EDT	TSTM WND DMG	Billerica, MA	TREE OR LARGE BRANCH DOWN NEAR CONNOLLY ROAD
Sep 13, 5:50 AM EDT	TSTM WND DMG	Boxford, MA	POWER LINES DOWN ON GEORGETOWN ROAD

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 00:00Z, 9.6 hours before the alert went out and 149 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 59 J/kg
Mixed-layer CIN: -20 J/kg
Mixed-layer LCL: 1125 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 66 m²/s²
0-3 km storm-relative helicity: 114 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

580 
WUUS51 KBOX 130934
SVRBOX
MAC009-017-131030-
/O.NEW.KBOX.SV.W.0111.210913T0934Z-210913T1030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
534 AM EDT Mon Sep 13 2021

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Essex County in northeastern Massachusetts...
  Northeastern Middlesex County in northeastern Massachusetts...

* Until 630 AM EDT.

* At 534 AM EDT, a severe thunderstorm was located over Chelmsford,
  moving east at 50 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...
  Lowell, Lynn, Lawrence, Peabody, Methuen, Salem, Billerica,
  Beverly, Woburn, Chelmsford, Andover, Dracut, Tewksbury,
  Gloucester, North Andover, Saugus, Danvers, Wakefield, Reading and
  Burlington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4270 7080 4267 7073 4264 7076 4269 7063
      4265 7059 4258 7066 4253 7078 4256 7078
      4254 7090 4250 7089 4252 7085 4249 7086
      4253 7153 4270 7150 4274 7082 4270 7083
      4274 7079
TIME...MOT...LOC 0934Z 272DEG 44KT 4262 7140 

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

$$

BL

3 follow-up statements

233 
WWUS51 KBOX 130949
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
549 AM EDT Mon Sep 13 2021

MAC009-017-131030-
/O.CON.KBOX.SV.W.0111.000000T0000Z-210913T1030Z/
Essex MA-Middlesex MA-
549 AM EDT Mon Sep 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 AM EDT
FOR ESSEX AND NORTHEASTERN MIDDLESEX COUNTIES...

At 549 AM EDT, a severe thunderstorm was located over Middleton, or
near Danvers, moving east at 65 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...
Lowell, Lynn, Lawrence, Peabody, Methuen, Salem, Billerica, Beverly,
Woburn, Chelmsford, Andover, Dracut, Tewksbury, Gloucester, North
Andover, Saugus, Danvers, Wakefield, Reading and Burlington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4270 7080 4267 7073 4264 7076 4269 7063
      4265 7059 4258 7066 4253 7078 4256 7078
      4254 7090 4250 7089 4252 7085 4249 7086
      4252 7134 4271 7132 4274 7082 4270 7083
      4274 7079
TIME...MOT...LOC 0949Z 270DEG 55KT 4262 7102 

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

$$

BL

387 
WWUS51 KBOX 130956
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
556 AM EDT Mon Sep 13 2021

MAC009-017-131030-
/O.CON.KBOX.SV.W.0111.000000T0000Z-210913T1030Z/
Essex MA-Middlesex MA-
556 AM EDT Mon Sep 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 AM EDT
FOR CENTRAL ESSEX AND EAST CENTRAL MIDDLESEX COUNTIES...

At 556 AM EDT, a severe thunderstorm was located over Wenham, or near
Danvers, moving east at 60 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Lynn, Lawrence, Peabody, Salem, Beverly, Woburn, Andover, Tewksbury,
Gloucester, North Andover, Saugus, Danvers, Wakefield, Reading,
Burlington, Wilmington, Marblehead, North Reading, Ipswich and
Lynnfield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4270 7080 4267 7073 4264 7076 4269 7063
      4265 7059 4258 7066 4253 7078 4256 7078
      4254 7090 4250 7089 4252 7085 4249 7086
      4251 7118 4272 7117 4274 7082 4270 7083
      4274 7079
TIME...MOT...LOC 0956Z 272DEG 52KT 4261 7089 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

BL

355 
WWUS51 KBOX 131005
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
605 AM EDT Mon Sep 13 2021

MAC009-017-131015-
/O.CAN.KBOX.SV.W.0111.000000T0000Z-210913T1030Z/
Essex MA-Middlesex MA-
605 AM EDT Mon Sep 13 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL ESSEX AND EAST CENTRAL
MIDDLESEX COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.  However gusty winds are
still possible with this thunderstorm.

LAT...LON 4270 7080 4267 7073 4264 7076 4269 7063
      4265 7059 4258 7066 4253 7078 4256 7078
      4254 7090 4250 7089 4252 7085 4249 7086
      4251 7118 4272 7117 4274 7082 4270 7083
      4274 7079
TIME...MOT...LOC 1003Z 272DEG 44KT 4261 7074 

$$

BL

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 13, 2:44 AM EDT	Special Weather Statement	BOX	Essex	46 min
Sep 13, 3:14 AM EDT	Severe Thunderstorm Warning	BOX	Essex, Middlesex	31 min
Sep 13, 3:17 AM EDT	Special Marine Warning	BOX		43 min
Sep 13, 3:51 AM EDT	Special Marine Warning	BOX		25 min
Sep 13, 5:24 AM EDT	Special Weather Statement	BOX	Essex	66 min
Sep 13, 5:39 AM EDT	Special Marine Warning	BOX		66 min
Sep 13, 8:02 AM EDT	Special Marine Warning	BOX		43 min

Nearby

Severe Thunderstorm Warnings in Massachusetts, 2021 Every 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.