Alert archive / Massachusetts / Tornado Watches in 2015

Tornado Watch 345

June 23, 20155 states

The Storm Prediction Center issued this tornado watch at Jun 23, 2015, 3:47 PM EDT for 5 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Jun 23, 2015, 3:47 PM EDT (19:47 UTC)
Expired
Jun 23, 2015, 10:46 PM EDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 33 counties

Capitol Planning Region, CT, Northeastern Connecticut Planning Region, CT, Barnstable County, MA, Bristol County, MA, Dukes County, MA, Essex County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Middlesex County, MA, Nantucket County, MA, Norfolk County, MA, Plymouth County, MA, Suffolk County, MA, Worcester County, MA, Cumberland County, ME, Oxford County, ME, York County, ME, Belknap County, NH, Carroll County, NH, Cheshire County, NH, Coos County, NH, Grafton County, NH, Hillsborough County, NH, Merrimack County, NH, Rockingham County, NH, Strafford County, NH, Sullivan County, NH, Bristol County, RI, Kent County, RI, Newport County, RI, Providence County, RI, Washington County, RI

The radar

The Boston radar (KBOX), 98 km from the middle of the area, began a volume at 19:50 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

25 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Jun 23, 4:21 PM EDTSevere Thunderstorm WarningBOXCapitol Planning Region39 min
Jun 23, 4:28 PM EDTSevere Thunderstorm WarningBOXNortheastern Connecticut Planning Region47 min
Jun 23, 4:57 PM EDTSevere Thunderstorm WarningBOXCapitol Planning Region, Northeastern Connecticut Planning Region40 min
Jun 23, 5:08 PM EDTSevere Thunderstorm WarningBOXBristol, Norfolk, Worcester52 min
Jun 23, 5:09 PM EDTSevere Thunderstorm WarningGYXYork51 min
Jun 23, 5:14 PM EDTSevere Thunderstorm WarningGYXCoos46 min
Jun 23, 5:16 PM EDTTornado WarningBOXBristol, Norfolk, Worcester44 min
Jun 23, 5:20 PM EDTSevere Thunderstorm WarningBOXNortheastern Connecticut Planning Region40 min
Jun 23, 5:25 PM EDTTornado WarningGYXCoos35 min
Jun 23, 5:30 PM EDTTornado WarningGYXBelknap, Carroll, Grafton30 min
Jun 23, 5:42 PM EDTSevere Thunderstorm WarningBOXBristol48 min
Jun 23, 5:46 PM EDTTornado WarningBOXBristol, Norfolk, Plymouth30 min
Jun 23, 5:50 PM EDTSevere Thunderstorm WarningGYXFranklin, Oxford40 min
Jun 23, 5:57 PM EDTSevere Thunderstorm WarningBOXFranklin, Worcester48 min
Jun 23, 5:57 PM EDTSevere Thunderstorm WarningGYXCoos48 min
Jun 23, 5:58 PM EDTSevere Thunderstorm WarningGYXYork47 min
Jun 23, 6:10 PM EDTTornado WarningBOXPlymouth30 min
Jun 23, 6:39 PM EDTSevere Thunderstorm WarningGYXFranklin, Oxford51 min
Jun 23, 6:45 PM EDTSevere Thunderstorm WarningGYXCumberland, York45 min
Jun 23, 7:01 PM EDTSevere Thunderstorm WarningBOXFranklin, Middlesex, Worcester47 min
Jun 23, 7:19 PM EDTSevere Thunderstorm WarningBOXCapitol Planning Region41 min
Jun 23, 7:45 PM EDTSevere Thunderstorm WarningBOXNortheastern Connecticut Planning Region45 min
Jun 23, 8:13 PM EDTSevere Thunderstorm WarningBOXCapitol Planning Region47 min
Jun 23, 8:22 PM EDTSevere Thunderstorm WarningBOXWashington32 min
Jun 23, 9:30 PM EDTSevere Thunderstorm WarningBOXBarnstable39 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Gray, ME (KGYX), launched 12:00Z, 7.8 hours before the alert went out and 165 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, Gray, ME at 12:00Z on 2015-06-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 17 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, Gray, ME at 12:00Z on 2015-06-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 187 square meters per square second.19395878Sfc1 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
17 J/kg
Mixed-layer CIN
-121 J/kg
Mixed-layer LCL
952 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
187 m²/s²
0-3 km storm-relative helicity
241 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

153 
WWUS20 KWNS 231945
SEL5  
SPC WW 231945
CTZ000-MAZ000-MEZ000-NHZ000-RIZ000-CWZ000-240300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 345
NWS STORM PREDICTION CENTER NORMAN OK
345 PM EDT TUE JUN 23 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  EASTERN CONNECTICUT
  MUCH OF MASSACHUSETTS
  FAR SOUTHERN MAINE
  CENTRAL AND SOUTHERN NEW HAMPSHIRE
  RHODE ISLAND
  COASTAL WATERS

* EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 345 PM UNTIL
  1100 PM EDT.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
  ISOLATED LARGE HAIL EVENTS TO 1 INCH IN DIAMETER POSSIBLE

SUMMARY...THUNDERSTORMS CONTINUE TO INCREASE IN COVERAGE AND
INTENSITY ACROSS EASTERN NEW YORK AND ADJACENT WESTERN NEW ENGLAND
THIS AFTERNOON...AND SHOULD CONTINUE TO INCREASE AS THEY MOVE
EASTWARD TOWARD THE ATLANTIC SEABOARD.  DAMAGING WINDS AND SOME HAIL
ARE EXPECTED...ALONG WITH POTENTIAL FOR A COUPLE OF TORNADOES.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE
MILES EAST AND WEST OF A LINE FROM 25 MILES NORTHEAST OF CONCORD
NEW HAMPSHIRE TO 10 MILES WEST OF PROVIDENCE RHODE ISLAND.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU5).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 341...WW 342...WW
343...WW 344...

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
MEAN STORM MOTION VECTOR 27040.


...GOSS

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 23, 8:57 AM EDTMesoscale DiscussionSPC63 min
Jun 23, 10:12 AM EDTSevere Thunderstorm WatchSPCGreater Bridgeport Planning Region, Capitol Planning Region, Northwest Hills Planning Region, Lower Connecticut River Valley Planning Region, Naugatuck Valley Planning Region, Southeastern Connecticut Planning Region and 1 more6 hr
Jun 23, 2:46 PM EDTMesoscale DiscussionSPC89 min
Jun 23, 3:35 PM EDTSevere Thunderstorm WatchSPCGreater Bridgeport Planning Region, Northwest Hills Planning Region, Lower Connecticut River Valley Planning Region, Naugatuck Valley Planning Region, Southeastern Connecticut Planning Region6 hr
Jun 23, 4:53 PM EDTMesoscale DiscussionSPC97 min
Jun 23, 6:55 PM EDTMesoscale DiscussionSPC95 min

Nearby

Tornado Watches in Massachusetts, 2015Tornado Watches in New Hampshire, 2015Tornado Watches in Rhode Island, 2015Every tornado watch in 2015

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.