Alert archive / South Dakota / Severe Thunderstorm Watches in 2017
Severe Thunderstorm Watch 469
The Storm Prediction Center issued this severe thunderstorm watch at Aug 26, 2017, 2:04 PM MDT for 9 counties in Nebraska; 17 counties in South Dakota. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 26, 2017, 2:04 PM MDT (20:04 UTC)
- Expired
- Aug 26, 2017, 8:54 PM MDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2.5 in
- Strongest gust expected
- 65 kt
All 26 counties
Box Butte County, NE, Cherry County, NE, Dawes County, NE, Garden County, NE, Grant County, NE, Hooker County, NE, Morrill County, NE, Sheridan County, NE, Thomas County, NE, Bennett County, SD, Corson County, SD, Custer County, SD, Dewey County, SD, Fall River County, SD, Haakon County, SD, Jackson County, SD, Jones County, SD, Lawrence County, SD, Meade County, SD, Mellette County, SD, Oglala Lakota County, SD, Pennington County, SD, Perkins County, SD, Stanley County, SD, Todd County, SD, Ziebach County, SD
The radar
The Rapid City radar (KUDX), 43 km from the middle of the area, began a volume at 20:05 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
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 40%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
24 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 26, 2:47 PM MDT | Severe Thunderstorm Warning | UNR | Custer, Fall River, Oglala Lakota | 58 min |
| Aug 26, 3:14 PM MDT | Severe Thunderstorm Warning | UNR | Lawrence, Meade | 46 min |
| Aug 26, 3:27 PM MDT | Severe Thunderstorm Warning | UNR | Haakon, Meade, Pennington, Ziebach | 63 min |
| Aug 26, 3:28 PM MDT | Severe Thunderstorm Warning | UNR | Fall River, Oglala Lakota | 50 min |
| Aug 26, 3:30 PM MDT | Tornado Warning | CYS | Dawes | 30 min |
| Aug 26, 3:30 PM MDT | Tornado Warning | UNR | Fall River, Oglala Lakota | 17 min |
| Aug 26, 3:53 PM MDT | Severe Thunderstorm Warning | UNR | Haakon, Jackson | 67 min |
| Aug 26, 3:57 PM MDT | Severe Thunderstorm Warning | UNR | Meade | 63 min |
| Aug 26, 3:58 PM MDT | Severe Thunderstorm Warning | CYS | Dawes | 62 min |
| Aug 26, 4:05 PM MDT | Severe Thunderstorm Warning | UNR | Lawrence, Meade | 25 min |
| Aug 26, 4:27 PM MDT | Severe Thunderstorm Warning | UNR | Meade, Pennington | 24 min |
| Aug 26, 4:30 PM MDT | Severe Thunderstorm Warning | UNR | Meade | 23 min |
| Aug 26, 4:45 PM MDT | Severe Thunderstorm Warning | UNR | Haakon, Jackson, Mellette | 60 min |
| Aug 26, 4:54 PM MDT | Severe Thunderstorm Warning | CYS | Box Butte, Dawes | 66 min |
| Aug 26, 5:37 PM MDT | Severe Thunderstorm Warning | UNR | Bennett, Jackson, Mellette, Todd | 53 min |
| Aug 26, 5:38 PM MDT | Severe Thunderstorm Warning | UNR | Meade | 52 min |
| Aug 26, 5:59 PM MDT | Severe Thunderstorm Warning | CYS | Box Butte | 28 min |
| Aug 26, 6:00 PM MDT | Severe Thunderstorm Warning | ABR | Jones | 17 min |
| Aug 26, 6:01 PM MDT | Severe Thunderstorm Warning | LBF | Cherry, Hooker | 44 min |
| Aug 26, 6:10 PM MDT | Severe Thunderstorm Warning | UNR | Meade | 50 min |
| Aug 26, 6:17 PM MDT | Severe Thunderstorm Warning | LBF | Garden, Sheridan | 29 min |
| Aug 26, 6:29 PM MDT | Severe Thunderstorm Warning | UNR | Meade | 61 min |
| Aug 26, 7:08 PM MDT | Severe Thunderstorm Warning | UNR | Meade, Ziebach | 33 min |
| Aug 26, 7:42 PM MDT | Severe Thunderstorm Warning | ABR | Jones | 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
Rapid City, SD (KRAP), launched 12:00Z, 8.1 hours before the alert went out and 44 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
- 69 J/kg
- Mixed-layer CIN
- -227 J/kg
- Mixed-layer LCL
- 2080 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 55 m²/s²
- 0-3 km storm-relative helicity
- 110 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 |
|---|---|---|---|---|
| Aug 26, 1:13 PM MDT | Mesoscale Discussion | SPC | Arthur, Box Butte, Cherry, Dawes, Garden, Grant and 3 more | 3 hr |
| Aug 26, 3:24 PM MDT | Mesoscale Discussion | SPC | Arthur, Blaine, Box Butte, Cherry, Dawes, Garden and 6 more | 2 hr |
| Aug 26, 3:46 PM MDT | Mesoscale Discussion | SPC | Furnas, Hitchcock, Red Willow | 2 hr |
Nearby
Severe Thunderstorm Watches in South Dakota, 2017Severe Thunderstorm Watches in Nebraska, 2017Every severe thunderstorm watch in 2017
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.