Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 88, NWS Boston/Norton, MA

July 23, 2021Essex County, Middlesex County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 23, 2021, 4:57 PM EDT for Essex County, Middlesex County, Massachusetts. It was in force for 63 min. 7 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: Jul 23, 2021, 4:57 PM EDT (20:57 UTC)
Expired: Jul 23, 2021, 6:00 PM EDT
In force: 63 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), 91 km from the middle of the area, began a volume at 20:58 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
Jul 23, 5:05 PM EDT	HAIL 0.88	Haverhill, MA
Jul 23, 5:09 PM EDT	HAIL 1	Merrimac, MA
Jul 23, 5:19 PM EDT	HAIL 0.5	West Newbury, MA
Jul 23, 5:20 PM EDT	HAIL 1	Haverhill, MA
Jul 23, 5:35 PM EDT	HAIL 1.25	1 W Georgetown, MA	ON ROUTE 97 BETWEEN GROVELAND AND GEORGETOWN MA
Jul 23, 5:36 PM EDT	HAIL 0.5	Georgetown, MA	AT I-95 AND RT 133
Jul 23, 5:40 PM EDT	HAIL 0.5	Boxford, MA

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, 9.0 hours before the alert went out and 136 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: 16 J/kg
Mixed-layer CIN: -94 J/kg
Mixed-layer LCL: 1504 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -19 m²/s²
0-3 km storm-relative helicity: -5 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

403 
WUUS51 KBOX 232057
SVRBOX
MAC009-017-232200-
/O.NEW.KBOX.SV.W.0088.210723T2057Z-210723T2200Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
457 PM EDT Fri Jul 23 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 600 PM EDT.

* At 457 PM EDT, a severe thunderstorm was located over Merrimac, or
  near Haverhill, moving south at 15 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...
  Haverhill, Peabody, Salem, Beverly, Gloucester, North Andover,
  Danvers, Newburyport, Amesbury, North Reading, Ipswich, Lynnfield,
  Middleton, Salisbury, Georgetown, Boxford, Hamilton, Newbury,
  Groveland and Merrimac.

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.

&&

LAT...LON 4282 7086 4281 7087 4280 7083 4277 7081
      4275 7083 4273 7081 4276 7081 4270 7078
      4270 7080 4267 7074 4260 7069 4250 7103
      4282 7113 4281 7107 4286 7103 4289 7090
TIME...MOT...LOC 2057Z 340DEG 11KT 4282 7099 

HAIL...1.00IN
WIND...60MPH
 
$$

Loconto

4 follow-up statements

684 
WWUS51 KBOX 232119
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
519 PM EDT Fri Jul 23 2021

MAC009-017-232200-
/O.CON.KBOX.SV.W.0088.000000T0000Z-210723T2200Z/
Essex MA-Middlesex MA-
519 PM EDT Fri Jul 23 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM EDT
FOR ESSEX AND NORTHEASTERN MIDDLESEX COUNTIES...

At 518 PM EDT, a severe thunderstorm was located over Georgetown, or
near Haverhill, moving south at 15 mph.

HAZARD...Ping pong ball size hail and 60 mph wind gusts.

SOURCE...Public and broadcast media. At 500 PM, quarter size hail 
         was reported in Merrimac.

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

Locations impacted include...
Haverhill, Peabody, Salem, Beverly, Gloucester, North Andover,
Danvers, Newburyport, Amesbury, North Reading, Ipswich, Lynnfield,
Middleton, Salisbury, Georgetown, Boxford, Hamilton, Newbury,
Groveland and Merrimac.

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.

&&

LAT...LON 4282 7086 4281 7087 4280 7083 4277 7081
      4275 7083 4273 7081 4276 7081 4270 7078
      4270 7080 4267 7074 4260 7069 4250 7103
      4282 7113 4281 7107 4286 7103 4289 7090
TIME...MOT...LOC 2118Z 340DEG 11KT 4276 7096 

HAIL...1.50IN
WIND...60MPH
 
$$

Loconto

506 
WWUS51 KBOX 232133
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
533 PM EDT Fri Jul 23 2021

MAC009-017-232200-
/O.CON.KBOX.SV.W.0088.000000T0000Z-210723T2200Z/
Essex MA-Middlesex MA-
533 PM EDT Fri Jul 23 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM EDT
FOR CENTRAL ESSEX AND NORTHEASTERN MIDDLESEX COUNTIES...

At 533 PM EDT, a severe thunderstorm was located over Boxford, or
near North Andover, moving south at 15 mph.

HAZARD...Ping pong ball size hail and 60 mph wind gusts.

SOURCE...Public. Quarter size hail was reported in Merrimac from 
         this severe thunderstorm.

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

Locations impacted include...
Haverhill, Peabody, Salem, Beverly, North Andover, Danvers, North
Reading, Ipswich, Lynnfield, Middleton, Georgetown, Boxford,
Hamilton, Newbury, Groveland, Topsfield, Rowley, Manchester, Wenham
and West Newbury.

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.

&&

LAT...LON 4279 7088 4278 7086 4275 7084 4268 7084
      4264 7082 4258 7078 4250 7103 4274 7108
      4278 7105 4279 7100
TIME...MOT...LOC 2133Z 346DEG 12KT 4268 7097 

HAIL...1.50IN
WIND...60MPH
 
$$

Loconto

012 
WWUS51 KBOX 232142
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
542 PM EDT Fri Jul 23 2021

MAC009-017-232200-
/O.CON.KBOX.SV.W.0088.000000T0000Z-210723T2200Z/
Essex MA-Middlesex MA-
542 PM EDT Fri Jul 23 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM EDT
FOR CENTRAL ESSEX AND NORTHEASTERN MIDDLESEX COUNTIES...

At 541 PM EDT, a severe thunderstorm was located over Topsfield, or
near Danvers, moving south at 15 mph.

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

SOURCE...Public. Quarter size hail was reported in Merrimac around 
         509 PM from this severe storm. 

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

Locations impacted include...
Peabody, Beverly, North Andover, Danvers, North Reading, Ipswich,
Lynnfield, Middleton, Georgetown, Boxford, Hamilton, Topsfield,
Rowley and Wenham.

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.

&&

LAT...LON 4272 7091 4271 7088 4269 7087 4266 7086
      4263 7084 4257 7085 4251 7099 4250 7102
      4268 7107 4269 7107 4272 7101 4273 7097
TIME...MOT...LOC 2141Z 340DEG 11KT 4265 7096 

HAIL...1.00IN
WIND...60MPH
 
$$

Loconto

447 
WWUS51 KBOX 232157
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
557 PM EDT Fri Jul 23 2021

MAC009-017-232206-
/O.EXP.KBOX.SV.W.0088.000000T0000Z-210723T2200Z/
Essex MA-Middlesex MA-
557 PM EDT Fri Jul 23 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL ESSEX AND NORTHEASTERN
MIDDLESEX COUNTIES WILL EXPIRE AT 600 PM EDT...
                
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 will be allowed to expire.  However small
hail, gusty winds and heavy rain are still possible with this
thunderstorm.

LAT...LON 4272 7091 4271 7088 4269 7087 4266 7086
      4263 7084 4257 7085 4251 7099 4250 7102
      4268 7107 4269 7107 4272 7101 4273 7097
TIME...MOT...LOC 2156Z 340DEG 11KT 4263 7095 

$$

Loconto

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 23, 2:28 PM EDT	Special Weather Statement	BOX	Middlesex	32 min
Jul 23, 2:49 PM EDT	Coastal Flood Statement	BOX	Barnstable, Essex, Nantucket, Norfolk, Plymouth, Suffolk	11 hr
Jul 23, 3:04 PM EDT	Special Weather Statement	BOX	Essex	26 min
Jul 23, 3:28 PM EDT	Severe Thunderstorm Warning	BOX	Essex, Middlesex, Suffolk	47 min
Jul 23, 3:29 PM EDT	Special Marine Warning	BOX		61 min
Jul 23, 4:41 PM EDT	Special Weather Statement	BOX	Essex	34 min
Jul 23, 5:23 PM EDT	Special Weather Statement	BOX	Bristol	52 min
Jul 23, 5:50 PM EDT	Special Marine Warning	BOX		55 min
Jul 23, 6:09 PM EDT	Severe Thunderstorm Warning	BOX	Bristol, Plymouth	26 min
Jul 23, 6:25 PM EDT	Special Weather Statement	BOX	Plymouth	50 min
Jul 23, 6:32 PM EDT	Special Weather Statement	BOX	Worcester	43 min
Jul 23, 6:42 PM EDT	Severe Thunderstorm Warning	BOX	Bristol, Norfolk, Plymouth	48 min
Jul 23, 7:28 PM EDT	Severe Thunderstorm Warning	BOX	Plymouth	34 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.