Alert archive / Massachusetts / Severe Thunderstorm Warnings in 1993

Severe Thunderstorm Warning 21, NWS Boston/Norton, MA

July 7, 1993Middlesex County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 7, 1993, 3:45 PM EDT for Middlesex County, Massachusetts. It was in force for 60 min.

The area

The counties it named.

The facts

Issued
Jul 7, 1993, 3:45 PM EDT (19:45 UTC)
Expired
Jul 7, 1993, 4:45 PM EDT
In force
60 min
Issued by
NWS Boston/Norton, MA
Area
Whole counties

County Middlesex County, MA

The nearest sounding before it

Chatham, MA (KCHH), launched 12:00Z, 7.8 hours before the alert went out and 148 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 1993-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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 1993-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 129 square meters per square second.1939Sfc1 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
1 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1020 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
129 m²/s²
0-3 km storm-relative helicity
97 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.

000 
TTAA00 KBOS 071946
SVRBOS
MAC017-072045-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE BOSTON MA
345 PM EDT WED JUL 7 1993
 
THE NATIONAL WEATHER SERVICE IN BOSTON HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  445 PM EDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN  MASSACHUSETTS
 
   ...NORTHERN MIDDLESEX COUNTY
 
RADAR INDICATED A THUNDERSTORM IM NORTHWEST MIDDLESEX COUNTY THAT MAY
BECOME SEVERE BY 350 PM AS IT CROSSES NEAR GROTON. THIS STORM COULD
BRING DAMAGING WIND...LARGE HAIL AND RAINFALL OF 1 INCH TO PARTS OF
NORTHERN MIDDLESEX COUNTY NEAR CHELMSFORD...GROTON AND LITTLETON BY 420
PM.
 
DRAG
 
 
IF THREATENING WEATHER APPROACHES...GO TO A SHAFE PLACE IMMEDIATELY.
IF SEVERE WEATHER OCCURS...ASK YOUR NEAREST LAW ENFORCEMENT AGENCY TO
RELAY YOUR SEVERE WEATHER REPORT TO THE NATIONAL WEATHER SERVICE.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 7, 5:01 PM EDTSevere Thunderstorm WarningBOXWorcester59 min
Jul 7, 5:56 PM EDTSevere Thunderstorm WarningBOXWorcester64 min
Jul 7, 6:43 PM EDTSevere Thunderstorm WarningBOXBristol47 min

Nearby

Severe Thunderstorm Warnings in Massachusetts, 1993Every severe thunderstorm warning in 1993

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.