Alert archive / South Dakota / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 450
The Storm Prediction Center issued this severe thunderstorm watch at Jul 1, 2012, 4:49 PM MDT for 8 counties in South Dakota. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 1, 2012, 4:49 PM MDT (22:49 UTC)
- Expired
- Jul 1, 2012, 10:36 PM MDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
Counties Butte County, SD, Custer County, SD, Fall River County, SD, Harding County, SD, Lawrence County, SD, Meade County, SD, Pennington County, SD, Perkins County, SD
The radar
The Rapid City radar (KUDX), 102 km from the middle of the area, began a volume at 22:51 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
5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 1, 5:48 PM MDT | Severe Thunderstorm Warning | UNR | Fall River | 57 min |
| Jul 1, 5:59 PM MDT | Severe Thunderstorm Warning | UNR | Butte, Lawrence, Meade | 61 min |
| Jul 1, 7:54 PM MDT | Severe Thunderstorm Warning | UNR | Harding | 66 min |
| Jul 1, 9:00 PM MDT | Severe Thunderstorm Warning | UNR | Harding, Perkins | 60 min |
| Jul 1, 9:38 PM MDT | Severe Thunderstorm Warning | UNR | Perkins | 56 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 (KUNR), launched 12:00Z, 10.8 hours before the alert went out and 103 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
- 979 J/kg
- Mixed-layer CIN
- -306 J/kg
- Mixed-layer LCL
- 1390 m above ground
- 0-6 km bulk shear
- 14 kt
- 0-1 km storm-relative helicity
- -63 m²/s²
- 0-3 km storm-relative helicity
- -81 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 30, 8:33 PM MDT | Mesoscale Discussion | SPC | Flathead, Lake, Lincoln, Mineral, Missoula, Sanders | 2 hr |
| Jul 1, 2:40 PM MDT | Mesoscale Discussion | SPC | Carter, Custer, Daniels, Dawson, Fallon, Garfield and 10 more | 2 hr |
| Jul 1, 4:04 PM MDT | Severe Thunderstorm Watch | SPC | Big Horn, Carter, Custer, Daniels, Dawson, Fallon and 13 more | 9 hr |
| Jul 1, 4:34 PM MDT | Mesoscale Discussion | SPC | Beaverhead, Blaine, Broadwater, Carbon, Cascade, Chouteau and 19 more | 86 min |
| Jul 1, 5:04 PM MDT | Severe Thunderstorm Watch | SPC | Beaverhead, Blaine, Broadwater, Carbon, Cascade, Chouteau and 18 more | 6 hr |
| Jun 30, 6:19 PM MDT | Mesoscale Discussion | SPC | Campbell, Corson, Dewey, Fall River, Haakon, Jackson and 4 more | 86 min |
Nearby
Severe Thunderstorm Watches in South Dakota, 2012Every severe thunderstorm watch in 2012
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.