Alert archive / South Dakota / Mesoscale Discussions in 2011
Mesoscale Discussion 1783
The Storm Prediction Center issued this mesoscale discussion at Jul 29, 2011, 12:59 PM MDT for 4 states. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Jul 29, 2011, 12:59 PM MDT (18:59 UTC)
- Expired
- Jul 29, 2011, 2:30 PM MDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
All 27 counties
Carter County, MT, Banner County, NE, Box Butte County, NE, Dawes County, NE, Kimball County, NE, Scotts Bluff County, NE, Sheridan County, NE, Sioux County, NE, Bennett County, SD, Butte County, SD, Custer County, SD, Fall River County, SD, Haakon County, SD, Harding County, SD, Jackson County, SD, Lawrence County, SD, Meade County, SD, Oglala Lakota County, SD, Pennington County, SD, Perkins County, SD, Ziebach County, SD, Crook County, WY, Goshen County, WY, Laramie County, WY, Niobrara County, WY, Platte County, WY, Weston County, WY
The radar
The Rapid City radar (KUDX), 131 km from the middle of the area, began a volume at 18:58 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.
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Rapid City, SD (KUNR), launched 12:00Z, 7.0 hours before the alert went out and 124 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
- 1117 J/kg
- Mixed-layer CIN
- -137 J/kg
- Mixed-layer LCL
- 1219 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 40 m²/s²
- 0-3 km storm-relative helicity
- 72 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted, in the capitals the NWS used until 2016.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 29, 1:54 PM MDT | Severe Thunderstorm Watch | SPC | Carter, Custer, Fallon, Powder River | 7 hr |
| Jul 29, 4:46 PM MDT | Mesoscale Discussion | SPC | Carter, Custer, Daniels, Dawson, Fallon, McCone and 5 more | 59 min |
| Jul 29, 5:02 PM MDT | Severe Thunderstorm Watch | SPC | Daniels, Dawson, McCone, Prairie, Richland, Roosevelt and 2 more | 6 hr |
Nearby
Mesoscale Discussions in South Dakota, 2011Mesoscale Discussions in Nebraska, 2011Mesoscale Discussions in Wyoming, 2011Every mesoscale discussion 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.