Alert archive / South Dakota / Tornado Watches in 2009
Tornado Watch 582
The Storm Prediction Center issued this tornado watch at Jul 13, 2009, 8:42 PM MDT for 19 counties in South Dakota. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 13, 2009, 8:42 PM MDT (02:42 UTC)
- Expired
- Jul 14, 2009, 12:45 AM MDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
Counties Bennett County, SD, Buffalo County, SD, Dewey County, SD, Haakon County, SD, Hughes County, SD, Hyde County, SD, Jackson County, SD, Jones County, SD, Lyman County, SD, Meade County, SD, Mellette County, SD, Pennington County, SD, Potter County, SD, Stanley County, SD, Sully County, SD, Todd County, SD, Tripp County, SD, Walworth County, SD, Ziebach County, SD
The radar
The Rapid City radar (KUDX), 130 km from the middle of the area, began a volume at 02:44 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
- 40%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 50%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 13, 8:58 PM MDT | Severe Thunderstorm Warning | UNR | Custer, Haakon, Jackson, Meade, Mellette, Pennington and 1 more | 92 min |
| Jul 13, 9:04 PM MDT | Severe Thunderstorm Warning | UNR | Bennett, Jackson, Mellette, Todd | 56 min |
| Jul 13, 9:17 PM MDT | Tornado Warning | UNR | Haakon | 43 min |
| Jul 13, 9:23 PM MDT | Severe Thunderstorm Warning | ABR | Dewey, Potter, Sully | 34 min |
| Jul 14, 12:17 AM MDT | Flash Flood Warning | ABR | Brown, Clark, Day, Edmunds, Faulk, McPherson and 3 more | 3 hr |
| Jul 14, 12:23 AM MDT | Flash Flood Warning | ABR | Buffalo, Hand, Hughes, Hyde, Sully | 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, 2.7 hours before the alert went out and 232 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
- 91 J/kg
- Mixed-layer CIN
- -30 J/kg
- Mixed-layer LCL
- 1137 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 81 m²/s²
- 0-3 km storm-relative helicity
- 162 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 |
|---|---|---|---|---|
| Jul 13, 7:47 PM MDT | Mesoscale Discussion | SPC | Bennett, Butte, Corson, Dewey, Haakon, Harding and 13 more | 58 min |
| Jul 13, 10:24 PM MDT | Mesoscale Discussion | SPC | Aurora, Brule, Buffalo, Charles Mix, Dewey, Douglas and 15 more | 66 min |
| Jul 14, 12:42 PM MDT | Mesoscale Discussion | SPC | Brookings, Codington, Deuel, Grant, Hamlin, Lake and 6 more | 93 min |
| Jul 14, 1:40 PM MDT | Severe Thunderstorm Watch | SPC | Bon Homme, Brookings, Clay, Codington, Deuel, Grant and 14 more | 6 hr |
Nearby
Tornado Watches in South Dakota, 2009Every tornado watch in 2009
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.