Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 69, NWS Boston/Norton, MA

July 14, 20214 counties in Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 14, 2021, 7:46 PM EDT for 4 counties in Massachusetts. It was in force for 26 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 14, 2021, 7:46 PM EDT (23:46 UTC)
Expired
Jul 14, 2021, 8:12 PM EDT
In force
26 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Franklin County, MA, Hampden County, MA, Hampshire County, MA, Worcester County, MA

The radar

The Boston radar (KBOX), 102 km from the middle of the area, began a volume at 23:50 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 12:00Z, 11.8 hours before the alert went out and 135 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-pSkew-T log-p diagram, Albany, NY at 12:00Z on 2021-07-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 20 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Albany, NY at 12:00Z on 2021-07-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 129 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
20 J/kg
Mixed-layer CIN
-211 J/kg
Mixed-layer LCL
871 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
129 m²/s²
0-3 km storm-relative helicity
134 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

254 
WUUS51 KBOX 142346
SVRBOX
MAC011-013-015-027-150045-
/O.NEW.KBOX.SV.W.0069.210714T2346Z-210715T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
746 PM EDT Wed Jul 14 2021

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Southwestern Worcester County in central Massachusetts...
  Southeastern Hampshire County in western Massachusetts...
  Southeastern Franklin County in western Massachusetts...
  East central Hampden County in western Massachusetts...

* Until 845 PM EDT.

* At 746 PM EDT, a severe thunderstorm was located over Ludlow, or
  near Chicopee, moving east 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...
  Springfield, Chicopee, Ludlow, South Hadley, Southbridge,
  Belchertown, Wilbraham, Charlton, Palmer, Spencer, Ware,
  Sturbridge, Monson, Rutland, Granby, Warren, Paxton, North
  Brookfield, West Brookfield and Brimfield.

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 4212 7256 4230 7257 4235 7197 4208 7197
TIME...MOT...LOC 2346Z 269DEG 16KT 4222 7247 

HAIL...0.75IN
WIND...60MPH
 
$$

RM
1 follow-up statement
832 
WWUS51 KBOX 150012
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
812 PM EDT Wed Jul 14 2021

MAC011-013-015-027-150022-
/O.CAN.KBOX.SV.W.0069.000000T0000Z-210715T0045Z/
Worcester MA-Hampshire MA-Franklin MA-Hampden MA-
812 PM EDT Wed Jul 14 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN WORCESTER...
SOUTHEASTERN HAMPSHIRE...SOUTHEASTERN FRANKLIN AND EAST CENTRAL
HAMPDEN 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 heavy rain is
still possible with this thunderstorm.

LAT...LON 4212 7256 4230 7257 4235 7197 4208 7197
TIME...MOT...LOC 0011Z 269DEG 16KT 4222 7231 

$$

RM

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 14, 12:32 AM EDTDense Fog AdvisoryBOXBarnstable, Bristol, Dukes, Essex, Middlesex, Nantucket and 4 more9 hr
Jul 14, 3:36 AM EDTSpecial Weather StatementBOXHampden, Hampshire39 min
Jul 14, 4:15 AM EDTSpecial Weather StatementBOXHampden, Hampshire45 min
Jul 14, 4:46 PM EDTSpecial Weather StatementBOXWorcester44 min
Jul 14, 4:53 PM EDTSevere Thunderstorm WarningBOXFranklin, Worcester52 min
Jul 14, 5:30 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampshire, Worcester45 min
Jul 14, 6:05 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire, Worcester40 min
Jul 14, 6:38 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire, Worcester52 min
Jul 14, 7:16 PM EDTFlash Flood WarningBOXHampshire53 min
Jul 14, 7:31 PM EDTSpecial Weather StatementBOXWorcester44 min
Jul 14, 7:33 PM EDTSpecial Weather StatementBOXHampden42 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.