Alert archive / Massachusetts / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 711
The Storm Prediction Center issued this severe thunderstorm watch at Aug 1, 2011, 2:34 PM EDT for 6 counties in Connecticut; 10 counties in Massachusetts; 5 counties in Rhode Island. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 1, 2011, 2:34 PM EDT (18:34 UTC)
- Expired
- Aug 1, 2011, 8:44 PM EDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 21 counties
Capitol Planning Region, CT, Greater Bridgeport Planning Region, CT, Lower Connecticut River Valley Planning Region, CT, Naugatuck Valley Planning Region, CT, Northeastern Connecticut Planning Region, CT, Southeastern Connecticut Planning Region, CT, Bristol County, MA, Essex County, MA, Franklin County, MA, Hampden County, MA, Hampshire 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), 89 km from the middle of the area, began a volume at 18:36 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
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- 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
21 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 1, 3:05 PM EDT | Severe Thunderstorm Warning | BOX | Northeastern Connecticut Planning Region | 17 min |
| Aug 1, 3:14 PM EDT | Severe Thunderstorm Warning | BOX | Franklin, Hampshire, Worcester | 38 min |
| Aug 1, 3:18 PM EDT | Severe Thunderstorm Warning | BOX | Franklin, Worcester | 42 min |
| Aug 1, 3:30 PM EDT | Severe Thunderstorm Warning | BOX | Franklin, Hampden, Hampshire, Worcester | 45 min |
| Aug 1, 3:41 PM EDT | Severe Thunderstorm Warning | BOX | Capitol Planning Region | 49 min |
| Aug 1, 3:59 PM EDT | Severe Thunderstorm Warning | BOX | Franklin, Worcester | 61 min |
| Aug 1, 4:07 PM EDT | Flash Flood Warning | BOX | Franklin, Worcester | 82 min |
| Aug 1, 4:18 PM EDT | Severe Thunderstorm Warning | BOX | Capitol Planning Region | 29 min |
| Aug 1, 4:31 PM EDT | Severe Thunderstorm Warning | BOX | Franklin, Worcester | 27 min |
| Aug 1, 4:35 PM EDT | Severe Thunderstorm Warning | BOX | Capitol Planning Region | 24 min |
| Aug 1, 4:40 PM EDT | Severe Thunderstorm Warning | OKX | Greater Bridgeport Planning Region | 65 min |
| Aug 1, 4:42 PM EDT | Severe Thunderstorm Warning | BOX | Franklin, Hampshire, Worcester | 63 min |
| Aug 1, 5:10 PM EDT | Severe Thunderstorm Warning | BOX | Capitol Planning Region | 35 min |
| Aug 1, 5:32 PM EDT | Severe Thunderstorm Warning | OKX | Greater Bridgeport Planning Region | 58 min |
| Aug 1, 5:34 PM EDT | Severe Thunderstorm Warning | OKX | Naugatuck Valley Planning Region | 56 min |
| Aug 1, 5:38 PM EDT | Severe Thunderstorm Warning | OKX | Greater Bridgeport Planning Region | 52 min |
| Aug 1, 5:57 PM EDT | Severe Thunderstorm Warning | OKX | Lower Connecticut River Valley Planning Region | 63 min |
| Aug 1, 6:20 PM EDT | Severe Thunderstorm Warning | OKX | Naugatuck Valley Planning Region | 40 min |
| Aug 1, 6:26 PM EDT | Flash Flood Warning | OKX | Naugatuck Valley Planning Region | 2 hr |
| Aug 1, 6:52 PM EDT | Severe Thunderstorm Warning | OKX | Greater Bridgeport Planning Region | 53 min |
| Aug 1, 6:55 PM EDT | Severe Thunderstorm Warning | OKX | Greater Bridgeport Planning Region, Lower Connecticut River Valley Planning Region, Naugatuck Valley Planning Region | 48 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
Brookhaven, NY (KOKX), launched 12:00Z, 6.6 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.
- Mixed-layer CAPE
- 529 J/kg
- Mixed-layer CIN
- -74 J/kg
- Mixed-layer LCL
- 975 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 25 m²/s²
- 0-3 km storm-relative helicity
- 52 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.4
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 1, 2:15 PM EDT | Mesoscale Discussion | SPC | 90 min | |
| Aug 1, 6:18 PM EDT | Mesoscale Discussion | SPC | 57 min | |
| Aug 1, 12:07 PM EDT | Mesoscale Discussion | SPC | Berkshire | 53 min |
Nearby
Severe Thunderstorm Watches in Massachusetts, 2011Severe Thunderstorm Watches in Connecticut, 2011Severe Thunderstorm Watches in Rhode Island, 2011Every severe thunderstorm watch 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.