Alert archive / South Dakota / Severe Thunderstorm Watches in 2007
Severe Thunderstorm Watch 152
The Storm Prediction Center issued this severe thunderstorm watch at Apr 20, 2007, 1:26 PM CDT for 6 counties in North Dakota; 33 counties in South Dakota. It was in force for 10 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 20, 2007, 1:26 PM CDT (18:26 UTC)
- Expired
- Apr 20, 2007, 11:00 PM CDT
- In force
- 10 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 39 counties
Dickey County, ND, LaMoure County, ND, McIntosh County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND, Aurora County, SD, Beadle County, SD, Bennett County, SD, Brown County, SD, Brule County, SD, Buffalo County, SD, Campbell County, SD, Charles Mix County, SD, Clark County, SD, Day County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Gregory County, SD, Haakon County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jackson County, SD, Jerauld County, SD, Jones County, SD, Lyman County, SD, Marshall County, SD, McPherson County, SD, Mellette County, SD, Potter County, SD, Roberts County, SD, Spink County, SD, Stanley County, SD, Sully County, SD, Todd County, SD, Tripp County, SD, Walworth County, SD
The radar
The Aberdeen radar (KABR), 65 km from the middle of the area, began a volume at 18:26 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
- 5%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 80%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
13 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 20, 1:30 PM CDT | Severe Thunderstorm Warning | ABR | Faulk, Hand | 30 min |
| Apr 20, 4:25 PM CDT | Severe Thunderstorm Warning | ABR | Hughes, Sully | 35 min |
| Apr 20, 6:18 PM CDT | Severe Thunderstorm Warning | ABR | Potter | 27 min |
| Apr 20, 6:21 PM CDT | Severe Thunderstorm Warning | BIS | Dickey, LaMoure | 39 min |
| Apr 20, 6:36 PM CDT | Severe Thunderstorm Warning | ABR | Faulk, Hyde | 39 min |
| Apr 20, 6:51 PM CDT | Severe Thunderstorm Warning | ABR | Brown | 24 min |
| Apr 20, 7:17 PM CDT | Severe Thunderstorm Warning | ABR | Faulk | 28 min |
| Apr 20, 7:33 PM CDT | Severe Thunderstorm Warning | FGF | Ransom | 33 min |
| Apr 20, 7:47 PM CDT | Severe Thunderstorm Warning | ABR | Faulk | 28 min |
| Apr 20, 8:01 PM CDT | Severe Thunderstorm Warning | ABR | Hand | 29 min |
| Apr 20, 8:17 PM CDT | Severe Thunderstorm Warning | ABR | Brown, Faulk, Spink | 43 min |
| Apr 20, 8:32 PM CDT | Severe Thunderstorm Warning | ABR | Hand | 28 min |
| Apr 20, 9:02 PM CDT | Severe Thunderstorm Warning | ABR | Brown | 28 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 12:00Z, 6.4 hours before the alert went out and 59 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 991 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- 132 m²/s²
- 0-3 km storm-relative helicity
- 287 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 |
|---|---|---|---|---|
| Apr 20, 1:05 PM CDT | Mesoscale Discussion | SPC | Dickey, Emmons, LaMoure, Logan, McIntosh | 55 min |
| Apr 20, 3:31 PM CDT | Mesoscale Discussion | SPC | Dickey, LaMoure, McIntosh, Ransom, Richland, Sargent | 119 min |
| Apr 20, 6:48 PM CDT | Mesoscale Discussion | SPC | Dickey, LaMoure, McIntosh, Ransom, Richland, Sargent | 117 min |
Nearby
Severe Thunderstorm Watches in South Dakota, 2007Severe Thunderstorm Watches in North Dakota, 2007Every severe thunderstorm watch in 2007
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.