Alert archive / Nebraska / Severe Thunderstorm Watches in 2020
Severe Thunderstorm Watch 421
The Storm Prediction Center issued this severe thunderstorm watch at Aug 8, 2020, 5:00 PM MDT for 31 counties in Nebraska; 13 counties in South Dakota. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 8, 2020, 5:00 PM MDT (23:00 UTC)
- Expired
- Aug 9, 2020, 12:00 AM MDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 65 kt
All 44 counties
Arthur County, NE, Banner County, NE, Blaine County, NE, Box Butte County, NE, Boyd County, NE, Brown County, NE, Cherry County, NE, Cheyenne County, NE, Custer County, NE, Dawes County, NE, Deuel County, NE, Garden County, NE, Garfield County, NE, Grant County, NE, Holt County, NE, Hooker County, NE, Keith County, NE, Keya Paha County, NE, Kimball County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Morrill County, NE, Perkins County, NE, Rock County, NE, Scotts Bluff County, NE, Sheridan County, NE, Sioux County, NE, Thomas County, NE, Wheeler County, NE, Bennett County, SD, Custer County, SD, Fall River County, SD, Haakon County, SD, Jackson County, SD, Lawrence County, SD, Meade County, SD, Mellette County, SD, Oglala Lakota County, SD, Pennington County, SD, Todd County, SD, Tripp County, SD, Ziebach County, SD
The radar
The Rapid City radar (KUDX), 146 km from the middle of the area, began a volume at 23:01 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
- 2%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 40%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
21 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 8, 5:05 PM MDT | Severe Thunderstorm Warning | UNR | Custer, Fall River | 28 min |
| Aug 8, 5:19 PM MDT | Severe Thunderstorm Warning | UNR | Lawrence, Meade, Pennington | 41 min |
| Aug 8, 5:28 PM MDT | Severe Thunderstorm Warning | UNR | Pennington | 47 min |
| Aug 8, 5:33 PM MDT | Severe Thunderstorm Warning | CYS | Dawes | 42 min |
| Aug 8, 5:49 PM MDT | Severe Thunderstorm Warning | UNR | Meade, Pennington | 56 min |
| Aug 8, 6:02 PM MDT | Severe Thunderstorm Warning | CYS | Dawes | 28 min |
| Aug 8, 6:12 PM MDT | Severe Thunderstorm Warning | LBF | Cherry, Sheridan | 63 min |
| Aug 8, 6:16 PM MDT | Severe Thunderstorm Warning | UNR | Custer, Fall River, Pennington | 44 min |
| Aug 8, 6:27 PM MDT | Severe Thunderstorm Warning | CYS | Box Butte, Morrill, Scotts Bluff, Sioux | 18 min |
| Aug 8, 6:29 PM MDT | Severe Thunderstorm Warning | CYS | Box Butte, Morrill, Scotts Bluff, Sioux | 19 min |
| Aug 8, 6:45 PM MDT | Severe Thunderstorm Warning | UNR | Custer, Fall River, Oglala Lakota, Pennington | 45 min |
| Aug 8, 7:14 PM MDT | Severe Thunderstorm Warning | LBF | Cherry, Sheridan | 61 min |
| Aug 8, 7:26 PM MDT | Severe Thunderstorm Warning | UNR | Bennett, Custer, Haakon, Jackson, Oglala Lakota, Pennington | 64 min |
| Aug 8, 7:59 PM MDT | Severe Thunderstorm Warning | LBF | Cherry, Grant, Hooker | 61 min |
| Aug 8, 8:27 PM MDT | Severe Thunderstorm Warning | UNR | Bennett, Haakon, Jackson, Mellette, Pennington, Todd | 63 min |
| Aug 8, 9:01 PM MDT | Severe Thunderstorm Warning | UNR | Mellette, Todd, Tripp | 59 min |
| Aug 8, 9:27 PM MDT | Severe Thunderstorm Warning | LBF | Blaine, Brown, Rock | 48 min |
| Aug 8, 9:55 PM MDT | Severe Thunderstorm Warning | UNR | Mellette, Todd, Tripp | 58 min |
| Aug 8, 10:23 PM MDT | Severe Thunderstorm Warning | LBF | Garfield, Holt, Loup, Rock | 52 min |
| Aug 8, 10:25 PM MDT | Severe Thunderstorm Warning | LBF | Boyd, Holt, Keya Paha, Rock | 50 min |
| Aug 8, 10:53 PM MDT | Severe Thunderstorm Warning | LBF | Boyd, Holt, Wheeler | 52 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
N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 11.0 hours before the alert went out and 246 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
- 523 J/kg
- Mixed-layer CIN
- -437 J/kg
- Mixed-layer LCL
- 2752 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- -41 m²/s²
- 0-3 km storm-relative helicity
- -36 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 8, 12:35 PM MDT | Mesoscale Discussion | SPC | Blaine, Brown, Custer, Dawson, Frontier, Garfield and 13 more | 115 min |
| Aug 8, 1:31 PM MDT | Mesoscale Discussion | SPC | Banner, Box Butte, Dawes, Garden, Morrill, Scotts Bluff and 2 more | 119 min |
| Aug 8, 3:55 PM MDT | Mesoscale Discussion | SPC | Hitchcock | 2 hr |
| Aug 8, 11:06 AM MDT | Mesoscale Discussion | SPC | Codington, Deuel, Grant, Hamlin | 114 min |
Nearby
Severe Thunderstorm Watches in Nebraska, 2020Severe Thunderstorm Watches in South Dakota, 2020Every severe thunderstorm watch in 2020
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.