Alert archive / South Dakota / Severe Thunderstorm Watches in 2018
Severe Thunderstorm Watch 305
The Storm Prediction Center issued this severe thunderstorm watch at Jul 22, 2018, 5:22 PM MDT for 21 counties in Nebraska; 23 counties in South Dakota. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 22, 2018, 5:22 PM MDT (23:22 UTC)
- Expired
- Jul 22, 2018, 11:55 PM MDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 44 counties
Arthur County, NE, Blaine County, NE, Boyd County, NE, Brown County, NE, Chase County, NE, Cherry County, NE, Custer County, NE, Frontier County, NE, Grant County, NE, Hayes County, NE, Holt County, NE, Hooker County, NE, Keith County, NE, Keya Paha County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Perkins County, NE, Rock County, NE, Thomas County, NE, Beadle County, SD, Brown County, SD, Brule County, SD, Buffalo County, SD, Campbell County, SD, Edmunds County, SD, Faulk County, SD, Gregory County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jerauld County, SD, Jones County, SD, Lyman County, SD, McPherson County, SD, Mellette County, SD, Potter 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), 187 km from the middle of the area, began a volume at 23:24 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
- 20%
- Ten or more severe hail reports
- 50%
- One or more hailstones of 2 inches or more
- 40%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
9 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 22, 5:41 PM MDT | Severe Thunderstorm Warning | UNR | Mellette, Todd | 64 min |
| Jul 22, 5:59 PM MDT | Severe Thunderstorm Warning | LBF | Arthur, Keith, Lincoln, McPherson | 46 min |
| Jul 22, 6:40 PM MDT | Severe Thunderstorm Warning | LBF | Keith, Perkins | 50 min |
| Jul 22, 6:43 PM MDT | Severe Thunderstorm Warning | UNR | Mellette, Todd, Tripp | 62 min |
| Jul 22, 6:57 PM MDT | Severe Thunderstorm Warning | LBF | Keith, Perkins | 48 min |
| Jul 22, 7:04 PM MDT | Severe Thunderstorm Warning | ABR | Jones, Lyman | 41 min |
| Jul 22, 7:21 PM MDT | Severe Thunderstorm Warning | ABR | Jones, Lyman | 24 min |
| Jul 22, 7:36 PM MDT | Severe Thunderstorm Warning | LBF | Chase, Hayes, Perkins | 39 min |
| Jul 22, 7:37 PM MDT | Severe Thunderstorm Warning | UNR | Mellette, Todd, Tripp | 53 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, 11.4 hours before the alert went out and 327 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
- 266 J/kg
- Mixed-layer CIN
- -337 J/kg
- Mixed-layer LCL
- 938 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 170 m²/s²
- 0-3 km storm-relative helicity
- 255 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 22, 4:11 PM MDT | Mesoscale Discussion | SPC | Arthur, Cherry, Hooker, Keith, McPherson, Thomas | 94 min |
| Jul 21, 8:40 PM MDT | Mesoscale Discussion | SPC | Butte, Custer, Fall River, Haakon, Harding, Jackson and 6 more | 65 min |
| Jul 22, 12:55 PM MDT | Mesoscale Discussion | SPC | Campbell, Corson, Dewey, Edmunds, Faulk, Haakon and 10 more | 3 hr |
Nearby
Severe Thunderstorm Watches in South Dakota, 2018Severe Thunderstorm Watches in Nebraska, 2018Every severe thunderstorm watch in 2018
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.