Alert archive / Massachusetts / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 1, NWS Boston/Norton, MA

May 7, 2011Hillsborough County, New Hampshire; Middlesex County, Worcester County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at May 7, 2011, 12:31 PM EDT for Hillsborough County, New Hampshire; Middlesex County, Worcester County, Massachusetts. It was in force for 29 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: May 7, 2011, 12:31 PM EDT (16:31 UTC)
Expired: May 7, 2011, 1:00 PM EDT
In force: 29 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon

Counties Middlesex County, MA, Worcester County, MA, Hillsborough County, NH

The radar

The Boston radar (KBOX), 93 km from the middle of the area, began a volume at 16:34 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
May 7, 12:51 PM EDT	HAIL 0.75	Townsend, MA	PENNY SIZE HAIL REPORTED.

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

The nearest sounding before it

Gray, ME (KGYX), launched 12:00Z, 4.5 hours before the alert went out and 175 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 55 J/kg
Mixed-layer CIN: -166 J/kg
Mixed-layer LCL: 1294 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 57 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

515 
WUUS51 KBOX 071631
SVRBOX
MAC017-027-NHC011-071700-
/O.NEW.KBOX.SV.W.0001.110507T1631Z-110507T1700Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TAUNTON MA
1231 PM EDT SAT MAY 7 2011

THE NATIONAL WEATHER SERVICE IN TAUNTON HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTH CENTRAL WORCESTER COUNTY IN CENTRAL MASSACHUSETTS...
  NORTHWESTERN MIDDLESEX COUNTY IN SOUTHEAST MASSACHUSETTS...
  EXTREME SOUTH CENTRAL HILLSBOROUGH COUNTY IN SOUTHERN NEW
  HAMPSHIRE...

* UNTIL 100 PM EDT

* AT 1230 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL.  THIS
  STORM WAS LOCATED NEAR TOWNSEND...OR 7 MILES NORTHEAST OF
  FITCHBURG...AND WAS MOVING EAST AT 15 MPH.

* SOME LOCATIONS IN THE WARNING INCLUDE...PEPPERELL AND HOLLIS.

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS AND LARGE HAIL...AS WELL
AS DEADLY LIGHTNING AND TORRENTIAL RAIN. GET TO SAFE SHELTER NOW...
INSIDE A STURDY BUILDING OR IN A VEHICLE. DO NOT SEEK SHELTER UNDER
TREES. IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY
LIGHTNING. DRIVERS SHOULD BE ALERT FOR PONDING OF WATER AND AVOID
FLOODED ROADS.

&&
LAT...LON 4275 7159 4266 7155 4262 7178 4268 7182
TIME...MOT...LOC 1631Z 251DEG 15KT 4267 7173

$$
FIELD

The office that day

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

Issued	Product	Office	Counties	Lasted
May 7, 12:10 PM EDT	Special Weather Statement	BOX	Hillsborough	50 min
May 7, 12:41 PM EDT	Special Weather Statement	BOX	Hillsborough	49 min
May 7, 12:48 PM EDT	Severe Thunderstorm Warning	BOX	Hillsborough	57 min
May 7, 1:58 PM EDT	Special Weather Statement	BOX	Rockingham	62 min
May 7, 2:49 PM EDT	Special Weather Statement	BOX	Hillsborough	41 min
May 7, 11:32 AM EDT	Special Weather Statement	BOX	Worcester	43 min
May 7, 12:28 PM EDT	Special Weather Statement	BOX	Middlesex	32 min
May 7, 1:08 PM EDT	Severe Thunderstorm Warning	BOX	Middlesex, Norfolk	52 min
May 7, 1:32 PM EDT	Special Weather Statement	BOX	Norfolk	43 min
May 7, 2:08 PM EDT	Special Weather Statement	BOX	Norfolk	37 min
May 7, 4:53 PM EDT	Special Weather Statement	BOX	Middlesex	52 min

Nearby

Severe Thunderstorm Warnings in Massachusetts, 2011 Severe Thunderstorm Warnings in New Hampshire, 2011 Every severe thunderstorm warning in 2011

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.