Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 113, NWS Boston/Norton, MA

August 23, 20205 counties in Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Aug 23, 2020, 4:34 PM EDT for 5 counties in Massachusetts. It was in force for 56 min. 9 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
Aug 23, 2020, 4:34 PM EDT (20:34 UTC)
Expired
Aug 23, 2020, 5:30 PM EDT
In force
56 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Essex County, MA, Middlesex County, MA, Norfolk County, MA, Suffolk County, MA, Worcester County, MA

The radar

The Boston radar (KBOX), 63 km from the middle of the area, began a volume at 20:37 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

TimeReportWhereRemark
Aug 23, 4:45 PM EDTTSTM WND DMGStoneham, MATREE DOWN ON CAR ON FRANKLIN ST
Aug 23, 4:45 PM EDTTSTM WND DMGWakefield, MATREES DOWN ON AVON AVE, GREEN ST. TREE DOWN ON HOUSE ON MAIN ST AT LAKE
Aug 23, 4:45 PM EDTHAIL 1Wakefield, MA
Aug 23, 4:50 PM EDTTSTM WND DMGWakefield, MATREE DOWN ON COMMUTER RAIL TRAIN TRACKS CAUSING DELAYS.
Aug 23, 4:50 PM EDTTSTM WND DMGWakefield, MAMYRTLE AVE BLOCKED BY 5 LARGE TREES - 4 DIAMETER
Aug 23, 4:55 PM EDTHAIL 0.75Lynn, MA
Aug 23, 5:00 PM EDTHAIL 0.75Boston, MAHYDE PARK SECTION OF BOSTON
Aug 23, 5:05 PM EDTTSTM WND DMGSaugus, MATREE DOWN ON WIRES ON HOBSON ST
Aug 23, 5:06 PM EDTTSTM WND DMGMalden, MATREE DOWN ON RTE 99 JUST BEFORE US RTE 1

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

The nearest sounding before it

Chatham, MA (KCHH), launched 12:00Z, 8.6 hours before the alert went out and 121 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, Chatham, MA at 12:00Z on 2020-08-23Temperature 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, Chatham, MA at 12:00Z on 2020-08-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 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
-159 J/kg
Mixed-layer LCL
1231 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
33 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

056 
WUUS51 KBOX 232034
SVRBOX
MAC009-017-021-025-027-232130-
/O.NEW.KBOX.SV.W.0113.200823T2034Z-200823T2130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
434 PM EDT Sun Aug 23 2020

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Suffolk County in eastern Massachusetts...
  North central Norfolk County in eastern Massachusetts...
  Southern Essex County in northeastern Massachusetts...
  East central Worcester County in central Massachusetts...
  Southeastern Middlesex County in northeastern Massachusetts...

* Until 530 PM EDT.

* At 433 PM EDT, a severe thunderstorm was located over Reading, or
  near Woburn, moving east at 15 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...
  Boston, Cambridge, Lynn, Newton, Somerville, Framingham, Waltham,
  Malden, Brookline, Medford, Revere, Peabody, Arlington, Everett,
  Salem, Billerica, Beverly, Marlborough, Woburn and Chelsea.

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 4270 7079 4264 7076 4269 7062 4258 7066
      4261 7066 4253 7078 4254 7090 4253 7088
      4244 7093 4242 7091 4245 7097 4233 7089
      4238 7105 4232 7100 4231 7104 4231 7097
      4219 7169 4255 7126 4272 7078
TIME...MOT...LOC 2033Z 266DEG 12KT 4255 7112 

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

Frank
2 follow-up statements
210 
WWUS51 KBOX 232042
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
442 PM EDT Sun Aug 23 2020

MAC009-017-021-025-027-232130-
/O.CON.KBOX.SV.W.0113.000000T0000Z-200823T2130Z/
Suffolk MA-Norfolk MA-Essex MA-Worcester MA-Middlesex MA-
442 PM EDT Sun Aug 23 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM EDT
FOR SUFFOLK...NORTH CENTRAL NORFOLK...SOUTHERN ESSEX...EAST CENTRAL
WORCESTER AND SOUTHEASTERN MIDDLESEX COUNTIES...

At 440 PM EDT, a severe thunderstorm was located over Reading, or
near Woburn, moving east at 15 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Trained weather spotters have indicated numerous reports of 
         wind damage and downed trees across parts of this region 
         over the past hour. Current radar indicates strong winds 
         will be entering Watertown, Stoneham, Melrose, Cambridge 
         and Boston.

IMPACT...Expect wind damage to trees and power lines. Minor hail 
         damage to vehicles is possible.

Locations impacted include...
Boston, Cambridge, Lynn, Newton, Somerville, Framingham, Waltham,
Malden, Brookline, Medford, Revere, Peabody, Arlington, Everett,
Salem, Billerica, Beverly, Marlborough, Woburn and Chelsea.

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 4270 7079 4264 7076 4269 7062 4258 7066
      4261 7066 4253 7078 4254 7090 4253 7088
      4244 7093 4242 7091 4245 7097 4233 7089
      4238 7105 4232 7100 4231 7104 4231 7097
      4219 7169 4255 7126 4272 7078
TIME...MOT...LOC 2040Z 266DEG 12KT 4255 7109 

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

Frank
331 
WWUS51 KBOX 232116
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
516 PM EDT Sun Aug 23 2020

MAC009-017-021-025-027-232130-
/O.CON.KBOX.SV.W.0113.000000T0000Z-200823T2130Z/
Suffolk MA-Norfolk MA-Essex MA-Worcester MA-Middlesex MA-
516 PM EDT Sun Aug 23 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM EDT
FOR SUFFOLK...NORTH CENTRAL NORFOLK...SOUTHEASTERN ESSEX...EAST
CENTRAL WORCESTER AND SOUTHEASTERN MIDDLESEX COUNTIES...

At 514 PM EDT, a severe thunderstorm was located over Lynn, moving
east at 15 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Trained weather spotters continue to report pockets of 
         significant wind damage and downed trees across central and 
         northeast Massachusetts. Seek an indoor shelter immediately.

IMPACT...Expect wind damage to trees and power lines. Minor hail 
         damage to vehicles is possible.

Locations impacted include...
Boston, Cambridge, Lynn, Newton, Somerville, Framingham, Waltham,
Malden, Brookline, Medford, Revere, Peabody, Arlington, Everett,
Salem, Beverly, Chelsea, Natick, Watertown and Lexington.

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 4240 7128 4264 7065 4258 7066 4261 7066
      4253 7078 4254 7084 4253 7088 4244 7093
      4242 7091 4245 7097 4244 7096 4245 7099
      4233 7089 4238 7105 4232 7100 4231 7104
      4231 7097 4219 7169 4240 7140
TIME...MOT...LOC 2114Z 265DEG 12KT 4248 7094 

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

Frank

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 23, 1:50 PM EDTSpecial Weather StatementBOXFranklin25 min
Aug 23, 2:17 PM EDTSpecial Weather StatementBOXFranklin43 min
Aug 23, 2:21 PM EDTSevere Thunderstorm WarningBOXFranklin, Worcester54 min
Aug 23, 2:36 PM EDTSpecial Weather StatementBOXEssex39 min
Aug 23, 3:14 PM EDTSevere Thunderstorm WarningBOXFranklin, Middlesex, Worcester61 min
Aug 23, 3:47 PM EDTSevere Thunderstorm WarningBOXEssex, Franklin, Middlesex, Worcester58 min
Aug 23, 4:01 PM EDTAreal Flood WarningBOXEssex119 min
Aug 23, 4:05 PM EDTSpecial Marine WarningBOX85 min
Aug 23, 4:12 PM EDTSevere Thunderstorm WarningBOXMiddlesex, Worcester63 min
Aug 23, 4:39 PM EDTSpecial Marine WarningBOX96 min
Aug 23, 4:44 PM EDTSevere Thunderstorm WarningBOXMiddlesex, Worcester50 min
Aug 23, 4:55 PM EDTSevere Thunderstorm WarningBOXMiddlesex, Worcester65 min
Aug 23, 5:04 PM EDTAreal Flood WarningBOXEssex, Middlesex, Plymouth, Suffolk116 min
Aug 23, 5:07 PM EDTSpecial Marine WarningBOX83 min
Aug 23, 5:12 PM EDTSevere Thunderstorm WarningBOXEssex, Middlesex, Norfolk, Plymouth, Suffolk63 min
Aug 23, 5:17 PM EDTAreal Flood WarningBOXMiddlesex, Worcester118 min
Aug 23, 5:28 PM EDTSevere Thunderstorm WarningBOXHampden, Hampshire, Worcester62 min
Aug 23, 5:38 PM EDTSevere Thunderstorm WarningBOXBristol, Middlesex, Norfolk, Plymouth, Suffolk, Worcester52 min
Aug 23, 5:47 PM EDTFlash Flood WarningBOXMiddlesex, Norfolk, Suffolk, Worcester118 min
Aug 23, 6:03 PM EDTSpecial Weather StatementBOXWorcester42 min
Aug 23, 6:10 PM EDTSevere Thunderstorm WarningBOXBristol, Norfolk, Plymouth49 min
Aug 23, 6:11 PM EDTSpecial Marine WarningBOX51 min
Aug 23, 6:15 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampshire, Worcester60 min
Aug 23, 6:20 PM EDTSevere Thunderstorm WarningBOXBristol, Norfolk, Plymouth, Worcester40 min
Aug 23, 6:26 PM EDTFlash Flood WarningBOXBristol, Norfolk, Plymouth, Suffolk2 hr
Aug 23, 6:32 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire, Worcester58 min
Aug 23, 6:39 PM EDTAreal Flood WarningBOXBristol, Norfolk, Worcester2 hr
Aug 23, 6:50 PM EDTSpecial Marine WarningBOX36 min
Aug 23, 6:55 PM EDTFlash Flood WarningBOXFranklin, Hampden, Hampshire, Worcester2 hr
Aug 23, 7:22 PM EDTSevere Thunderstorm WarningBOXHampden, Hampshire, Worcester53 min
Aug 23, 7:43 PM EDTAreal Flood WarningBOXMiddlesex, Norfolk, Suffolk, Worcester2 hr

Nearby

Severe Thunderstorm Warnings in Massachusetts, 2020Every severe thunderstorm warning in 2020

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.