Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 71, NWS Boston/Norton, MA
NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 16, 2021, 4:36 PM EDT for Middlesex County, Norfolk County, Worcester County, Massachusetts. It was in force for 35 min. 1 report 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 16, 2021, 4:36 PM EDT (20:36 UTC)
- Expired
- Jul 16, 2021, 5:11 PM EDT
- In force
- 35 min
- Issued by
- NWS Boston/Norton, MA
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Middlesex County, MA, Norfolk County, MA, Worcester County, MA
The radar
The Boston radar (KBOX), 53 km from the middle of the area, began a volume at 20:38 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 16, 5:00 PM EDT | TSTM WND DMG | Worcester, MA | LARGE LIMB ON POWER LINES AT GRANITE ST AND CLIFF ST. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Brookhaven, NY (KOKX), launched 12:00Z, 8.6 hours before the alert went out and 177 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
- 1044 J/kg
- Mixed-layer CIN
- -56 J/kg
- Mixed-layer LCL
- 994 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- 108 m²/s²
- 0-3 km storm-relative helicity
- 105 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
732
WUUS51 KBOX 162036
SVRBOX
MAC017-021-027-162130-
/O.NEW.KBOX.SV.W.0071.210716T2036Z-210716T2130Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
436 PM EDT Fri Jul 16 2021
The National Weather Service in Boston/Norton has issued a
* Severe Thunderstorm Warning for...
Southwestern Norfolk County in eastern Massachusetts...
Southeastern Worcester County in central Massachusetts...
South central Middlesex County in northeastern Massachusetts...
* Until 530 PM EDT.
* At 435 PM EDT, a severe thunderstorm was located over Auburn, or
near Worcester, moving east at 25 mph.
HAZARD...60 mph wind gusts, torrential rainfall and minor
flooding.
SOURCE...Radar indicated.
IMPACT...Expect damage to trees and power lines.
* Locations impacted include...
Worcester, Framingham, Shrewsbury, Natick, Franklin, Milford,
Westborough, Grafton, Ashland, Bellingham, Auburn, Northbridge,
Hopkinton, Northborough, Oxford, Holliston, Uxbridge, Millbury,
Charlton and Medway.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4217 7193 4229 7188 4231 7133 4203 7140
TIME...MOT...LOC 2035Z 280DEG 22KT 4222 7183
HAIL...<.75IN
WIND...60MPH
$$
Nocera1 follow-up statement
091
WWUS51 KBOX 162111
SVSBOX
Severe Weather Statement
National Weather Service Boston/Norton MA
511 PM EDT Fri Jul 16 2021
MAC017-021-027-162121-
/O.CAN.KBOX.SV.W.0071.000000T0000Z-210716T2130Z/
Norfolk MA-Worcester MA-Middlesex MA-
511 PM EDT Fri Jul 16 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN NORFOLK...
SOUTHEASTERN WORCESTER AND SOUTH CENTRAL MIDDLESEX COUNTIES IS
CANCELLED...
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled. However gusty winds and
heavy rain are still possible with this thunderstorm.
LAT...LON 4217 7193 4229 7188 4231 7133 4203 7140
TIME...MOT...LOC 2110Z 280DEG 22KT 4218 7154
$$The office that day
Everything else NWS Boston/Norton, MA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 16, 9:38 AM EDT | Heat Advisory | BOX | Bristol, Essex, Middlesex, Norfolk, Plymouth, Suffolk | 9 hr |
| Jul 16, 2:59 PM EDT | Flash Flood Watch | BOX | Franklin, Hampden, Hampshire, Worcester | 56 hr |
| Jul 16, 3:04 PM EDT | Severe Thunderstorm Warning | BOX | Norfolk, Worcester | 56 min |
| Jul 16, 3:41 PM EDT | Special Weather Statement | BOX | Hampden | 49 min |
| Jul 16, 4:26 PM EDT | Special Weather Statement | BOX | Norfolk, Suffolk | 49 min |
| Jul 16, 4:50 PM EDT | Special Marine Warning | BOX | 55 min | |
| Jul 16, 5:05 PM EDT | Severe Thunderstorm Warning | BOX | Hampden, Worcester | 55 min |
| Jul 16, 5:47 PM EDT | Severe Thunderstorm Warning | BOX | Bristol, Middlesex, Norfolk, Plymouth, Suffolk, Worcester | 33 min |
| Jul 16, 6:32 PM EDT | Special Marine Warning | BOX | 43 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.