Alert archive / South Dakota / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 696
The Storm Prediction Center issued this severe thunderstorm watch at Jul 28, 2011, 3:31 PM CDT for 27 counties in South Dakota. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 28, 2011, 3:31 PM CDT (20:31 UTC)
- Expired
- Jul 28, 2011, 8:57 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 27 counties
Buffalo County, SD, Butte County, SD, Campbell County, SD, Corson County, SD, Custer County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Haakon County, SD, Hand County, SD, Harding County, SD, Hughes County, SD, Hyde County, SD, Jackson County, SD, Jones County, SD, Lawrence County, SD, Lyman County, SD, McPherson County, SD, Meade County, SD, Mellette County, SD, Pennington County, SD, Perkins County, SD, Potter County, SD, Stanley County, SD, Sully County, SD, Walworth County, SD, Ziebach County, SD
The radar
The Rapid City radar (KUDX), 115 km from the middle of the area, began a volume at 20:33 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
- 40%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
14 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 28, 3:56 PM CDT | Severe Thunderstorm Warning | UNR | Custer, Pennington | 64 min |
| Jul 28, 4:05 PM CDT | Severe Thunderstorm Warning | UNR | Perkins, Ziebach | 55 min |
| Jul 28, 4:09 PM CDT | Severe Thunderstorm Warning | UNR | Harding | 66 min |
| Jul 28, 4:27 PM CDT | Severe Thunderstorm Warning | UNR | Butte, Harding | 63 min |
| Jul 28, 4:41 PM CDT | Severe Thunderstorm Warning | ABR | Corson | 49 min |
| Jul 28, 4:45 PM CDT | Severe Thunderstorm Warning | UNR | Harding, Perkins | 60 min |
| Jul 28, 4:49 PM CDT | Severe Thunderstorm Warning | UNR | Butte, Lawrence | 24 min |
| Jul 28, 4:58 PM CDT | Severe Thunderstorm Warning | UNR | Perkins, Ziebach | 62 min |
| Jul 28, 5:29 PM CDT | Severe Thunderstorm Warning | UNR | Ziebach | 61 min |
| Jul 28, 5:32 PM CDT | Severe Thunderstorm Warning | UNR | Butte, Harding | 58 min |
| Jul 28, 5:58 PM CDT | Severe Thunderstorm Warning | UNR | Perkins, Ziebach | 62 min |
| Jul 28, 6:13 PM CDT | Severe Thunderstorm Warning | ABR | Dewey | 62 min |
| Jul 28, 7:03 PM CDT | Severe Thunderstorm Warning | ABR | Dewey, Stanley, Sully | 57 min |
| Jul 28, 7:44 PM CDT | Severe Thunderstorm Warning | ABR | Dewey, Hughes, Stanley, Sully | 40 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
Bismarck Municip, ND (KBIS), launched 12:00Z, 8.5 hours before the alert went out and 225 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
- 135 J/kg
- Mixed-layer CIN
- -110 J/kg
- Mixed-layer LCL
- 1472 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km storm-relative helicity
- 41 m²/s²
- 0-3 km storm-relative helicity
- 43 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 |
|---|---|---|---|---|
| Jul 27, 7:09 PM CDT | Mesoscale Discussion | SPC | Dewey, Haakon, Jackson, Jones, Meade, Pennington and 2 more | 2 hr |
| Jul 28, 2:05 PM CDT | Mesoscale Discussion | SPC | Brown, Butte, Campbell, Corson, Dewey, Edmunds and 10 more | 115 min |
| Jul 28, 6:19 PM CDT | Mesoscale Discussion | SPC | Buffalo, Butte, Dewey, Haakon, Hughes, Hyde and 9 more | 86 min |
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.