Alert archive / South Dakota / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 692
The Storm Prediction Center issued this severe thunderstorm watch at Jul 26, 2011, 8:17 PM CDT for 8 counties in Minnesota; 20 counties in South Dakota. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 26, 2011, 8:17 PM CDT (01:17 UTC)
- Expired
- Jul 27, 2011, 4:00 AM CDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 28 counties
Cottonwood County, MN, Jackson County, MN, Lincoln County, MN, Lyon County, MN, Murray County, MN, Nobles County, MN, Pipestone County, MN, Rock County, MN, Aurora County, SD, Beadle County, SD, Bon Homme County, SD, Brookings County, SD, Brule County, SD, Charles Mix County, SD, Davison County, SD, Douglas County, SD, Gregory County, SD, Hanson County, SD, Hutchinson County, SD, Jerauld County, SD, Kingsbury County, SD, Lake County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Sanborn County, SD, Turner County, SD
The radar
The Sioux Falls radar (KFSD), 78 km from the middle of the area, began a volume at 01:19 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
9 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 26, 8:41 PM CDT | Severe Thunderstorm Warning | FSD | Beadle | 49 min |
| Jul 26, 9:02 PM CDT | Tornado Warning | FSD | Beadle | 14 min |
| Jul 26, 9:23 PM CDT | Severe Thunderstorm Warning | FSD | Beadle, Jerauld, Kingsbury, Miner, Sanborn | 36 min |
| Jul 26, 10:03 PM CDT | Severe Thunderstorm Warning | FSD | Jerauld | 42 min |
| Jul 26, 10:18 PM CDT | Severe Thunderstorm Warning | FSD | Aurora, Jerauld, Miner, Sanborn | 42 min |
| Jul 26, 10:54 PM CDT | Severe Thunderstorm Warning | FSD | Beadle, Brookings, Kingsbury, Lake, Miner, Sanborn | 40 min |
| Jul 26, 11:42 PM CDT | Severe Thunderstorm Warning | FSD | Lake, McCook, Minnehaha | 33 min |
| Jul 27, 12:16 AM CDT | Severe Thunderstorm Warning | FSD | McCook, Minnehaha | 44 min |
| Jul 27, 3:56 AM CDT | Flash Flood Warning | FSD | Lincoln, Minnehaha | 3 hr |
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, 1.3 hours before the alert went out and 123 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
- 3555 J/kg
- Mixed-layer CIN
- -42 J/kg
- Mixed-layer LCL
- 900 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 289 m²/s²
- 0-3 km storm-relative helicity
- 399 m²/s²
- Significant tornado parameter
- 7.2
- Supercell composite
- 32.6
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 27, 2:49 AM CDT | Mesoscale Discussion | SPC | Dickinson, Emmet, Lyon, Osceola | 56 min |
| Jul 27, 6:54 PM CDT | Mesoscale Discussion | SPC | Clayton, Clinton, Delaware, Dubuque, Jackson, Jones | 66 min |
| Jul 26, 7:24 PM CDT | Mesoscale Discussion | SPC | Big Stone, Grant, Stevens, Traverse, Wilkin | 36 min |
| Jul 26, 7:32 PM CDT | Tornado Watch | SPC | Big Stone, Chippewa, Douglas, Grant, Lac qui Parle, Otter Tail and 6 more | 5 hr |
| Jul 26, 8:10 PM CDT | Mesoscale Discussion | SPC | Big Stone, Douglas, Grant, Lac qui Parle, Otter Tail, Pope and 4 more | 95 min |
| Jul 26, 9:53 PM CDT | Mesoscale Discussion | SPC | Blue Earth, Brown, Carver, Chippewa, Cottonwood, Dakota and 37 more | 67 min |
| Jul 26, 10:10 PM CDT | Severe Thunderstorm Watch | SPC | Anoka, Benton, Blue Earth, Brown, Carver, Chippewa and 30 more | 8 hr |
| Jul 27, 3:49 PM CDT | Mesoscale Discussion | SPC | Custer, Fall River, Lawrence, Oglala Lakota, Pennington | 86 min |
Nearby
Severe Thunderstorm Watches in South Dakota, 2011Severe Thunderstorm Watches in Minnesota, 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.