Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 85, NWS Boston/Norton, MA
NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 20, 2021, 9:53 PM EDT for Franklin County, Hampshire County, Massachusetts. It was in force for 52 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
- Jul 20, 2021, 9:53 PM EDT (01:53 UTC)
- Expired
- Jul 20, 2021, 10:45 PM EDT
- In force
- 52 min
- Issued by
- NWS Boston/Norton, MA
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Franklin County, MA, Hampshire County, MA
The radar
The Albany radar (KENX), 101 km from the middle of the area, began a volume at 01:54 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
Albany, NY (KALY), launched 00:00Z, 1.9 hours before the alert went out and 81 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.
- Mixed-layer CAPE
- 1226 J/kg
- Mixed-layer CIN
- -24 J/kg
- Mixed-layer LCL
- 1198 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 89 m²/s²
- 0-3 km storm-relative helicity
- 82 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 4.6
The text
As transmitted.
068
WUUS51 KBOX 210153
SVRBOX
MAC011-015-210245-
/O.NEW.KBOX.SV.W.0085.210721T0153Z-210721T0245Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
953 PM EDT Tue Jul 20 2021
The National Weather Service in Boston/Norton has issued a
* Severe Thunderstorm Warning for...
Northern Hampshire County in western Massachusetts...
Northwestern Franklin County in western Massachusetts...
* Until 1045 PM EDT.
* At 953 PM EDT, a severe thunderstorm was located near Williamstown,
or near North Adams, moving east at 40 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect damage to trees and power lines.
* Locations impacted include...
Greenfield, Deerfield, Monroe, Montague, Sunderland, Northfield,
Bernardston, Buckland, Conway, Shelburne, Erving, Ashfield,
Colrain, Gill, Whately, Charlemont, Leyden, Heath, Plainfield and
Rowe.
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.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4273 7259 4270 7244 4245 7256 4255 7298
4263 7295 4267 7296 4266 7298 4267 7300
4270 7295 4270 7302 4274 7302
TIME...MOT...LOC 0153Z 289DEG 34KT 4275 7317
HAIL...<.75IN
WIND...60MPH
$$
RM1 follow-up statement
542
WWUS51 KBOX 210228
SVSBOX
Severe Weather Statement
National Weather Service Boston/Norton MA
1028 PM EDT Tue Jul 20 2021
MAC011-015-210245-
/O.CON.KBOX.SV.W.0085.000000T0000Z-210721T0245Z/
Hampshire MA-Franklin MA-
1028 PM EDT Tue Jul 20 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1045 PM EDT
FOR NORTHERN HAMPSHIRE AND NORTHWESTERN FRANKLIN COUNTIES...
At 1028 PM EDT, a severe thunderstorm was located near Heath, or 9
miles west of Greenfield, moving east at 40 mph.
HAZARD...60 mph wind gusts and penny size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to trees and power lines.
Locations impacted include...
Greenfield, Deerfield, Monroe, Montague, Northfield, Bernardston,
Buckland, Conway, Shelburne, Ashfield, Colrain, Gill, Whately,
Charlemont, Leyden, Heath, Plainfield, Rowe and Hawley.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4271 7247 4246 7261 4255 7298 4263 7295
4267 7296 4266 7298 4267 7300 4270 7295
4270 7302 4274 7302 4273 7259
TIME...MOT...LOC 0228Z 289DEG 34KT 4265 7278
HAIL...0.75IN
WIND...60MPH
$$
RMThe office that day
Everything else NWS Boston/Norton, MA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 20, 10:39 PM EDT | Special Weather Statement | BOX | Franklin | 66 min |
| Jul 20, 11:03 PM EDT | Special Weather Statement | BOX | Worcester | 57 min |
| Jul 20, 11:53 PM EDT | Special Weather Statement | BOX | Worcester | 67 min |
| Jul 21, 12:02 AM EDT | Special Weather Statement | BOX | Essex | 58 min |
| Jul 21, 7:27 PM EDT | Special Marine Warning | BOX | 63 min | |
| Jul 21, 7:39 PM EDT | Special Marine Warning | BOX | 66 min | |
| Jul 21, 7:50 PM EDT | Special Weather Statement | BOX | Suffolk | 40 min |
Nearby
Severe Thunderstorm Warnings in Massachusetts, 2021Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.