Alert archive / South Dakota / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 599
The Storm Prediction Center issued this severe thunderstorm watch at Jul 4, 2011, 11:41 PM CDT for 7 counties in Minnesota; 38 counties in South Dakota. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 4, 2011, 11:41 PM CDT (04:41 UTC)
- Expired
- Jul 5, 2011, 5:05 AM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 45 counties
Big Stone County, MN, Cottonwood County, MN, Lincoln County, MN, Lyon County, MN, Murray County, MN, Pipestone County, MN, Traverse County, MN, Aurora County, SD, Beadle County, SD, Brookings County, SD, Brown County, SD, Brule County, SD, Buffalo County, SD, Charles Mix County, SD, Clark County, SD, Codington County, SD, Davison County, SD, Day County, SD, Deuel County, SD, Douglas County, SD, Edmunds County, SD, Faulk County, SD, Grant County, SD, Gregory County, SD, Hamlin County, SD, Hand County, SD, Hanson County, SD, Hughes County, SD, Hutchinson County, SD, Hyde County, SD, Jerauld County, SD, Kingsbury County, SD, Lake County, SD, Lyman County, SD, Marshall County, SD, McCook County, SD, McPherson County, SD, Miner County, SD, Moody County, SD, Potter County, SD, Roberts County, SD, Sanborn County, SD, Spink County, SD, Sully County, SD, Walworth County, SD
The radar
The Aberdeen radar (KABR), 150 km from the middle of the area, began a volume at 04:43 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
- 5%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 90%
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 4, 11:58 PM CDT | Severe Thunderstorm Warning | ABR | Edmunds, Faulk, Hand, Hyde, Potter, Sully and 1 more | 62 min |
| Jul 5, 12:20 AM CDT | Severe Thunderstorm Warning | ABR | Traverse | 55 min |
| Jul 5, 12:24 AM CDT | Flash Flood Warning | ABR | Jones, Lyman, Stanley | 5 hr |
| Jul 5, 12:49 AM CDT | Severe Thunderstorm Warning | ABR | Big Stone | 41 min |
| Jul 5, 12:50 AM CDT | Severe Thunderstorm Warning | ABR | Brown | 55 min |
| Jul 5, 12:57 AM CDT | Severe Thunderstorm Warning | ABR | Big Stone, Traverse | 40 min |
| Jul 5, 1:35 AM CDT | Severe Thunderstorm Warning | ABR | Brown, Day, Edmunds, Faulk, Spink | 45 min |
| Jul 5, 1:53 AM CDT | Flash Flood Warning | ABR | Brown | 97 min |
| Jul 5, 2:41 AM CDT | Flash Flood Warning | ABR | Edmunds | 2 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, 4.7 hours before the alert went out and 93 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
- 3256 J/kg
- Mixed-layer CIN
- -52 J/kg
- Mixed-layer LCL
- 1088 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 94 m²/s²
- 0-3 km storm-relative helicity
- 150 m²/s²
- Significant tornado parameter
- 1.3
- Supercell composite
- 9.4
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 4, 7:14 PM CDT | Severe Thunderstorm Watch | SPC | Aitkin, Becker, Beltrami, Benton, Carlton, Cass and 38 more | 9 hr |
| Jul 4, 10:42 PM CDT | Mesoscale Discussion | SPC | Aitkin, Becker, Benton, Carlton, Cass, Clay and 19 more | 2 hr |
| Jul 5, 12:29 PM CDT | Mesoscale Discussion | SPC | Houston | 91 min |
| Jul 5, 3:32 PM CDT | Mesoscale Discussion | SPC | Nobles, Rock | 88 min |
| Jul 4, 7:59 PM CDT | Mesoscale Discussion | SPC | Beadle, Bennett, Brown, Brule, Buffalo, Campbell and 28 more | 2 hr |
| Jul 4, 11:14 PM CDT | Mesoscale Discussion | SPC | Aurora, Beadle, Bon Homme, Brown, Brule, Buffalo and 32 more | 91 min |
| Jul 5, 2:17 PM CDT | Mesoscale Discussion | SPC | Bennett, Custer, Fall River, Jackson, Mellette, Oglala Lakota and 1 more | 73 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.