Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 52, NWS Boston/Norton, MA

July 18, 20126 counties in Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 18, 2012, 2:39 PM EDT for 6 counties in Massachusetts. It was in force for 51 min. 4 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
Jul 18, 2012, 2:39 PM EDT (18:39 UTC)
Expired
Jul 18, 2012, 3:30 PM EDT
In force
51 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon

Counties Bristol County, MA, Middlesex County, MA, Norfolk County, MA, Plymouth County, MA, Suffolk County, MA, Worcester County, MA

The radar

The Boston radar (KBOX), 33 km from the middle of the area, began a volume at 18:42 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
Jul 18, 2:40 PM EDTHAIL 0.75Framingham, MA
Jul 18, 2:43 PM EDTHAIL 0.75Natick, MA
Jul 18, 2:44 PM EDTHAIL 1.75Framingham, MA
Jul 18, 3:01 PM EDTHAIL 0.75Needham, MA

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 18, 12:20 PM EDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Chatham, MA (KCHH), launched 12:00Z, 6.7 hours before the alert went out and 111 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 2012-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1521 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Chatham, MA at 12:00Z on 2012-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 42 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
1521 J/kg
Mixed-layer CIN
-208 J/kg
Mixed-layer LCL
1597 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
42 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

488 
WUUS51 KBOX 181839
SVRBOX
MAC005-017-021-023-025-027-181930-
/O.NEW.KBOX.SV.W.0052.120718T1839Z-120718T1930Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TAUNTON MA
239 PM EDT WED JUL 18 2012

THE NATIONAL WEATHER SERVICE IN TAUNTON HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EXTREME NORTH CENTRAL BRISTOL COUNTY IN SOUTHEAST MASSACHUSETTS...
  SOUTH CENTRAL MIDDLESEX COUNTY IN SOUTHEAST MASSACHUSETTS...
  NORFOLK COUNTY IN EASTERN MASSACHUSETTS...
  EXTREME NORTHWESTERN PLYMOUTH COUNTY IN SOUTHEAST MASSACHUSETTS...
  SOUTHWESTERN SUFFOLK COUNTY IN EASTERN MASSACHUSETTS...
  EXTREME EAST CENTRAL WORCESTER COUNTY IN CENTRAL MASSACHUSETTS...

* UNTIL 330 PM EDT

* AT 236 PM EDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
  CAPABLE OF PRODUCING QUARTER SIZE HAIL AND DAMAGING WINDS IN
  EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR FRAMINGHAM...AND
  MOVING SOUTHEAST AT 30 MPH.

* LOCATIONS IMPACTED INCLUDE...
  BROCKTON...QUINCY...NEWTON...FRAMINGHAM...BROOKLINE...
  WEYMOUTH...AVON...BRAINTREE...RANDOLPH...STOUGHTON...NEEDHAM...
  NORWOOD...WESTWOOD...WELLESLEY...MILTON...DEDHAM...ABINGTON...
  ROCKLAND...WHITMAN AND HOLBROOK. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS IN EXCESS OF 60 MPH...
DESTRUCTIVE HAIL...DEADLY LIGHTNING AND VERY HEAVY RAIN. FOR YOUR
PROTECTION...MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

&&

LAT...LON 4199 7097 4224 7153 4240 7143 4229 7101
      4229 7102 4227 7099 4226 7097 4228 7095
      4226 7097 4225 7096 4226 7090 4225 7088
      4226 7087 4224 7081
TIME...MOT...LOC 1836Z 295DEG 25KT 4230 7142 

$$

KJC

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 17, 8:23 PM EDTSpecial Weather StatementBOXEssex67 min
Jul 18, 12:37 PM EDTSpecial Weather StatementBOXMiddlesex53 min
Jul 18, 12:41 PM EDTHeat AdvisoryBOXBristol, Essex, Franklin, Hampden, Hampshire, Middlesex and 2 more6 hr
Jul 18, 12:54 PM EDTSevere Thunderstorm WarningBOXEssex, Middlesex66 min
Jul 18, 1:21 PM EDTSpecial Marine WarningBOX84 min
Jul 18, 1:29 PM EDTFlash Flood WarningBOXEssex, Middlesex98 min
Jul 18, 1:43 PM EDTSevere Thunderstorm WarningBOXEssex, Middlesex, Suffolk36 min
Jul 18, 1:45 PM EDTSpecial Marine WarningBOX60 min
Jul 18, 1:50 PM EDTSpecial Weather StatementBOXHampden40 min
Jul 18, 2:04 PM EDTSevere Thunderstorm WarningBOXHampden, Hampshire, Worcester56 min
Jul 18, 2:04 PM EDTTornado WarningBOXEssex, Suffolk12 min
Jul 18, 2:21 PM EDTSevere Thunderstorm WarningBOXEssex, Middlesex, Suffolk39 min
Jul 18, 2:21 PM EDTSevere Thunderstorm WarningBOXHampden54 min
Jul 18, 2:24 PM EDTFlash Flood WarningBOXHampden, Worcester3 hr
Jul 18, 2:30 PM EDTSpecial Marine WarningBOX90 min
Jul 18, 2:44 PM EDTSevere Thunderstorm WarningBOXHampden, Norfolk, Worcester61 min
Jul 18, 3:09 PM EDTSevere Thunderstorm WarningBOXBristol, Norfolk, Worcester51 min
Jul 18, 3:46 PM EDTSevere Thunderstorm WarningBOXBarnstable, Bristol, Norfolk, Plymouth59 min
Jul 18, 4:04 PM EDTSpecial Marine WarningBOX56 min
Jul 18, 4:25 PM EDTSpecial Marine WarningBOX80 min
Jul 18, 4:42 PM EDTSevere Thunderstorm WarningBOXBarnstable, Plymouth36 min
Jul 18, 5:08 PM EDTSpecial Weather StatementBOXNorfolk, Suffolk52 min
Jul 18, 5:24 PM EDTFlash Flood WarningBOXMiddlesex, Norfolk, Suffolk78 min
Jul 18, 5:27 PM EDTSevere Thunderstorm WarningBOXMiddlesex, Norfolk, Plymouth, Suffolk48 min
Jul 18, 5:30 PM EDTSpecial Marine WarningBOX54 min
Jul 18, 6:08 PM EDTSpecial Marine WarningBOX67 min
Jul 18, 6:27 PM EDTSpecial Weather StatementBOXEssex33 min

Nearby

Severe Thunderstorm Warnings in Massachusetts, 2012Every severe thunderstorm warning in 2012

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.