Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 106, NWS Boston/Norton, MA
NWS Boston/Norton, MA issued this severe thunderstorm warning at Aug 19, 2021, 2:23 PM EDT for Middlesex County, Massachusetts. It was in force for 37 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, 2:23 PM EDT (18:23 UTC)
- Expired
- Aug 19, 2021, 3:00 PM EDT
- In force
- 37 min
- Issued by
- NWS Boston/Norton, MA
- Area
- Storm-based polygon
- Tornado
- Possible
- Hail
- 0.75 in
- Wind
- 60.0 mph
County Middlesex County, MA
The radar
The Boston radar (KBOX), 83 km from the middle of the area, began a volume at 18:23 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, 6.4 hours before the alert went out and 160 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
- 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
The text
As transmitted.
959
WUUS51 KBOX 191823
SVRBOX
MAC017-191900-
/O.NEW.KBOX.SV.W.0106.210819T1823Z-210819T1900Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
223 PM EDT Thu Aug 19 2021
The National Weather Service in Boston/Norton has issued a
* Severe Thunderstorm Warning for...
North central Middlesex County in northeastern Massachusetts...
* Until 300 PM EDT.
* At 223 PM EDT, a severe thunderstorm was located over Tyngsborough,
or near Dracut, moving northeast at 20 mph.
HAZARD...60 mph wind gusts and penny size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to trees and power lines.
* Locations impacted include...
Lowell, Chelmsford, Dracut, Westford, Pepperell, Tyngsborough and
Dunstable.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4268 7124 4267 7124 4261 7136 4269 7157
4270 7156 4270 7129 4274 7126
TIME...MOT...LOC 1823Z 225DEG 17KT 4269 7141
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Chai3 follow-up statements
685
WWUS51 KBOX 191837
SVSBOX
Severe Weather Statement
National Weather Service Boston/Norton MA
237 PM EDT Thu Aug 19 2021
MAC017-191900-
/O.CON.KBOX.SV.W.0106.000000T0000Z-210819T1900Z/
Middlesex MA-
237 PM EDT Thu Aug 19 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM EDT
FOR NORTH CENTRAL MIDDLESEX COUNTY...
At 237 PM EDT, a severe thunderstorm was located over Pelham, or near
Dracut, moving northeast at 20 mph.
HAZARD...60 mph wind gusts and penny size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to trees and power lines.
Locations impacted include...
Lowell, Dracut and Tyngsborough.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4268 7124 4267 7124 4263 7136 4270 7143
4270 7129 4274 7126
TIME...MOT...LOC 1837Z 225DEG 17KT 4274 7134
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Chai526
WWUS51 KBOX 191850
SVSBOX
Severe Weather Statement
National Weather Service Boston/Norton MA
250 PM EDT Thu Aug 19 2021
MAC017-191900-
/O.CON.KBOX.SV.W.0106.000000T0000Z-210819T1900Z/
Middlesex MA-
250 PM EDT Thu Aug 19 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM EDT
FOR NORTHEASTERN MIDDLESEX COUNTY...
At 249 PM EDT, a severe thunderstorm was located near Pelham, or near
Salem, moving northeast at 20 mph.
HAZARD...60 mph wind gusts and penny size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to trees and power lines.
Locations impacted include...
Dracut.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4268 7124 4268 7129 4270 7134 4270 7129
4274 7126
TIME...MOT...LOC 1849Z 225DEG 17KT 4278 7128
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Chai071
WWUS51 KBOX 191855
SVSBOX
Severe Weather Statement
National Weather Service Boston/Norton MA
255 PM EDT Thu Aug 19 2021
MAC017-191905-
/O.EXP.KBOX.SV.W.0106.000000T0000Z-210819T1900Z/
Middlesex MA-
255 PM EDT Thu Aug 19 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN MIDDLESEX COUNTY
WILL EXPIRE AT 300 PM EDT...
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.
LAT...LON 4268 7124 4268 7129 4270 7134 4270 7129
4274 7126
TIME...MOT...LOC 1855Z 225DEG 17KT 4280 7126
$$
ChaiThe office that day
Everything else NWS Boston/Norton, MA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 19, 8:14 AM EDT | Flash Flood Warning | BOX | Hampden, Worcester | 3 hr |
| Aug 19, 9:18 AM EDT | Flash Flood Warning | BOX | Hampden, Hampshire, Worcester | 3 hr |
| Aug 19, 10:14 AM EDT | Severe Thunderstorm Warning | BOX | Middlesex, Worcester | 44 min |
| Aug 19, 10:21 AM EDT | Tornado Warning | BOX | Middlesex, Worcester | 29 min |
| Aug 19, 10:46 AM EDT | Flash Flood Warning | BOX | Essex, Middlesex, Norfolk, Suffolk, Worcester | 3 hr |
| Aug 19, 11:36 AM EDT | Severe Thunderstorm Warning | BOX | Essex, Middlesex, Norfolk, Suffolk, Worcester | 54 min |
| Aug 19, 11:40 AM EDT | Flash Flood Warning | BOX | Essex, Middlesex | 3 hr |
| Aug 19, 12:32 PM EDT | Severe Thunderstorm Warning | BOX | Essex, Middlesex, Norfolk, Suffolk | 58 min |
| Aug 19, 12:33 PM EDT | Special Marine Warning | BOX | 57 min | |
| Aug 19, 12:49 PM EDT | Tornado Warning | BOX | Essex, Middlesex, Suffolk | 39 min |
| Aug 19, 1:18 PM EDT | Tornado Warning | BOX | Middlesex, Worcester | 27 min |
| Aug 19, 1:37 PM EDT | Special Weather Statement | BOX | Essex | 38 min |
| Aug 19, 1:38 PM EDT | Special Marine Warning | BOX | 67 min | |
| Aug 19, 1:46 PM EDT | Special Weather Statement | BOX | Barnstable | 59 min |
| Aug 19, 1:48 PM EDT | Special Marine Warning | BOX | 57 min | |
| Aug 19, 1:54 PM EDT | Special Weather Statement | BOX | Middlesex | 51 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.