Alert archive / Massachusetts / Severe Thunderstorm Watches in 2008

Severe Thunderstorm Watch 894

September 9, 2008Northeastern Connecticut Planning Region, Connecticut; 7 counties in Massachusetts; 5 counties in Rhode Island

The Storm Prediction Center issued this severe thunderstorm watch at Sep 9, 2008, 11:40 AM EDT for Northeastern Connecticut Planning Region, Connecticut; 7 counties in Massachusetts; 5 counties in Rhode Island. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Sep 9, 2008, 11:40 AM EDT (15:40 UTC)
Expired
Sep 9, 2008, 2:57 PM EDT
In force
3 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt

Counties Northeastern Connecticut Planning Region, CT, Bristol County, MA, Essex County, MA, Middlesex County, MA, Norfolk County, MA, Plymouth County, MA, Suffolk County, MA, Worcester County, MA, Bristol County, RI, Kent County, RI, Newport County, RI, Providence County, RI, Washington County, RI

The radar

The Boston radar (KBOX), 42 km from the middle of the area, began a volume at 15:43 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
10%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
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
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Sep 9, 11:52 AM EDTSevere Thunderstorm WarningBOXMiddlesex, Worcester38 min
Sep 9, 12:08 PM EDTSevere Thunderstorm WarningBOXNortheastern Connecticut Planning Region37 min
Sep 9, 12:16 PM EDTSevere Thunderstorm WarningBOXNortheastern Connecticut Planning Region44 min
Sep 9, 12:52 PM EDTSevere Thunderstorm WarningBOXEssex, Middlesex, Norfolk, Plymouth, Suffolk38 min
Sep 9, 12:57 PM EDTSevere Thunderstorm WarningBOXBristol, Norfolk, Plymouth, Worcester48 min
Sep 9, 1:44 PM EDTSevere Thunderstorm WarningBOXBristol, Plymouth31 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

Chatham, MA (KCHH), launched 12:00Z, 3.7 hours before the alert went out and 143 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 2008-09-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2008-09-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 52 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1524 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
52 m²/s²
0-3 km storm-relative helicity
79 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 9, 8:35 AM EDTMesoscale DiscussionSPC115 min
Sep 9, 9:33 AM EDTSevere Thunderstorm WatchSPCGreater Bridgeport Planning Region, Lower Connecticut River Valley Planning Region, Naugatuck Valley Planning Region, Southeastern Connecticut Planning Region6 hr
Sep 9, 11:39 AM EDTMesoscale DiscussionSPC36 min
Sep 9, 12:11 PM EDTMesoscale DiscussionSPC94 min

Nearby

Severe Thunderstorm Watches in Massachusetts, 2008Severe Thunderstorm Watches in Rhode Island, 2008Severe Thunderstorm Watches in Connecticut, 2008Every severe thunderstorm watch in 2008

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.