Alert archive / South Dakota / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 470
The Storm Prediction Center issued this severe thunderstorm watch at Jun 12, 2011, 7:33 PM CDT for 18 counties in South Dakota. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 12, 2011, 7:33 PM CDT (00:33 UTC)
- Expired
- Jun 13, 2011, 2:00 AM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
Counties Buffalo County, SD, Campbell County, SD, Corson County, SD, Dewey County, SD, Haakon County, SD, Hughes County, SD, Hyde County, SD, Jones County, SD, Lyman County, SD, Mellette County, SD, Perkins County, SD, Potter County, SD, Stanley County, SD, Sully County, SD, Todd County, SD, Tripp County, SD, Walworth County, SD, Ziebach County, SD
The radar
The Rapid City radar (KUDX), 140 km from the middle of the area, began a volume at 00:36 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
- 20%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 12, 7:44 PM CDT | Severe Thunderstorm Warning | UNR | Butte, Harding, Perkins | 61 min |
| Jun 12, 8:19 PM CDT | Severe Thunderstorm Warning | UNR | Harding, Perkins | 43 min |
| Jun 12, 8:40 PM CDT | Severe Thunderstorm Warning | ABR | Corson, Dewey | 65 min |
| Jun 12, 9:13 PM CDT | Severe Thunderstorm Warning | ABR | Hughes, Jones, Lyman, Stanley | 62 min |
| Jun 12, 9:42 PM CDT | Severe Thunderstorm Warning | ABR | Campbell, Corson, Dewey, Potter, Sully, Walworth | 45 min |
| Jun 12, 10:39 PM CDT | Severe Thunderstorm Warning | ABR | Edmunds, Potter, Walworth | 7 min |
| Jun 13, 12:47 AM CDT | Severe Thunderstorm Warning | UNR | Todd | 58 min |
| Jun 13, 1:36 AM CDT | Severe Thunderstorm Warning | UNR | Todd, Tripp | 54 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
Aberdeen, SD (KABR), launched 00:00Z, 0.6 hours before the alert went out and 228 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
- 70 J/kg
- Mixed-layer CIN
- -309 J/kg
- Mixed-layer LCL
- 1253 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 117 m²/s²
- 0-3 km storm-relative helicity
- 192 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 12, 7:07 PM CDT | Mesoscale Discussion | SPC | Brown, Buffalo, Corson, Dewey, Edmunds, Faulk and 16 more | 53 min |
| Jun 12, 9:55 PM CDT | Mesoscale Discussion | SPC | Bennett, Campbell, Corson, Dewey, Haakon, Hughes and 11 more | 65 min |
| Jun 13, 1:44 AM CDT | Mesoscale Discussion | SPC | Jones, Lyman, Mellette, Todd, Tripp | 61 min |
| Jun 13, 2:53 PM CDT | Mesoscale Discussion | SPC | Lyman, Mellette, Todd, Tripp | 2 hr |
| Jun 13, 5:24 PM CDT | Severe Thunderstorm Watch | SPC | Bennett, Fall River, Jackson, Mellette, Todd, Tripp | 7 hr |
Nearby
Severe Thunderstorm Watches in South Dakota, 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.