Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 55, NWS Boston/Norton, MA

July 7, 2021Franklin County, Hampshire County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 7, 2021, 4:01 PM EDT for Franklin County, Hampshire County, Massachusetts. It was in force for 59 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: Jul 7, 2021, 4:01 PM EDT (20:01 UTC)
Expired: Jul 7, 2021, 5:00 PM EDT
In force: 59 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Franklin County, MA, Hampshire County, MA

The radar

The Albany radar (KENX), 100 km from the middle of the area, began a volume at 20:02 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 7, 4:50 PM EDT	TSTM WND DMG	Northampton, MA	TREE DOWN ACROSS ROAD AT AUDOBON ROAD
Jul 7, 4:50 PM EDT	TSTM WND DMG	Northampton, MA	TREES AND WIRES DOWN ON SPRING STEEL STREET AND ON EASTHAMPTON ROAD

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 7, 2:41 PM EDT	Severe Thunderstorm Watch	SPC	10 hr

The nearest sounding before it

Albany, NY (KALY), launched 12:00Z, 8.0 hours before the alert went out and 85 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: 18 J/kg
Mixed-layer CIN: -132 J/kg
Mixed-layer LCL: 923 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 49 m²/s²
0-3 km storm-relative helicity: 64 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

220 
WUUS51 KBOX 072001
SVRBOX
MAC011-015-072100-
/O.NEW.KBOX.SV.W.0055.210707T2001Z-210707T2100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
401 PM EDT Wed Jul 7 2021

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Western Hampshire County in western Massachusetts...
  Central Franklin County in western Massachusetts...

* Until 500 PM EDT.

* At 401 PM EDT, a severe thunderstorm was located over East Windsor,
  or 12 miles east of Pittsfield, moving east at 20 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...
  Amherst, Northampton, Deerfield, South Hadley, Montague, Granby,
  Hadley, Sunderland, Hatfield, Williamsburg, Huntington, Conway,
  Leverett, Shutesbury, Ashfield, Westhampton, Whately, Chesterfield,
  Worthington and Goshen.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4238 7301 4239 7301 4252 7297 4256 7298
      4256 7297 4252 7245 4226 7252 4229 7261
      4238 7306
TIME...MOT...LOC 2001Z 281DEG 18KT 4248 7302 

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

Chai

1 follow-up statement

257 
WWUS51 KBOX 072046
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
446 PM EDT Wed Jul 7 2021

MAC011-015-072100-
/O.CON.KBOX.SV.W.0055.000000T0000Z-210707T2100Z/
Hampshire MA-Franklin MA-
446 PM EDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 500 PM EDT
FOR CENTRAL HAMPSHIRE AND WEST CENTRAL FRANKLIN COUNTIES...

At 446 PM EDT, a severe thunderstorm was located over Williamsburg,
or 7 miles north of Northampton, moving east at 20 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...
Amherst, Northampton, Deerfield, South Hadley, Granby, Hadley,
Sunderland, Hatfield, Williamsburg, Huntington, Conway, Leverett,
Shutesbury, Ashfield, Westhampton, Whately, Chesterfield,
Worthington, Goshen and Middlefield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4235 7288 4239 7287 4245 7285 4249 7284
      4248 7266 4248 7246 4226 7252 4229 7261
      4238 7306
TIME...MOT...LOC 2046Z 281DEG 18KT 4244 7272 

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

Chai

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 7, 4:00 PM EDT	Severe Thunderstorm Warning	BOX	Hampden, Hampshire	60 min
Jul 7, 4:05 PM EDT	Special Weather Statement	BOX	Essex	40 min
Jul 7, 4:33 PM EDT	Severe Thunderstorm Warning	BOX	Essex, Middlesex	57 min
Jul 7, 5:02 PM EDT	Special Weather Statement	BOX	Worcester	43 min
Jul 7, 5:05 PM EDT	Special Marine Warning	BOX		25 min
Jul 7, 5:10 PM EDT	Tropical Storm Watch	BOX	Barnstable, Bristol, Dukes, Nantucket, Plymouth	13 hr
Jul 7, 5:21 PM EDT	Severe Thunderstorm Warning	BOX	Hampden, Hampshire, Worcester	54 min
Jul 7, 5:24 PM EDT	Special Marine Warning	BOX		66 min
Jul 7, 5:30 PM EDT	Severe Thunderstorm Warning	BOX	Hampden, Worcester	60 min
Jul 7, 6:01 PM EDT	Special Weather Statement	BOX	Worcester	44 min
Jul 7, 6:17 PM EDT	Severe Thunderstorm Warning	BOX	Bristol, Middlesex, Norfolk, Worcester	58 min
Jul 7, 6:18 PM EDT	Severe Thunderstorm Warning	BOX	Middlesex, Worcester	36 min
Jul 7, 6:22 PM EDT	Special Marine Warning	BOX		53 min
Jul 7, 6:59 PM EDT	Severe Thunderstorm Warning	BOX	Bristol, Middlesex, Norfolk, Plymouth, Suffolk	61 min
Jul 7, 7:18 PM EDT	Special Marine Warning	BOX		57 min
Jul 7, 7:47 PM EDT	Severe Thunderstorm Warning	BOX	Norfolk, Plymouth	25 min
Jul 7, 7:51 PM EDT	Special Marine Warning	BOX		54 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.