Alert archive / Nebraska / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 199
The Storm Prediction Center issued this severe thunderstorm watch at May 23, 2021, 8:12 PM CDT for 13 counties in Kansas; 22 counties in Nebraska; Mellette County, Todd County, Tripp County, South Dakota. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- May 23, 2021, 8:12 PM CDT (01:12 UTC)
- Expired
- May 24, 2021, 1:00 AM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 38 counties
Cheyenne County, KS, Decatur County, KS, Gove County, KS, Graham County, KS, Greeley County, KS, Logan County, KS, Norton County, KS, Rawlins County, KS, Sheridan County, KS, Sherman County, KS, Thomas County, KS, Wallace County, KS, Wichita County, KS, Blaine County, NE, Brown County, NE, Chase County, NE, Cherry County, NE, Custer County, NE, Dawson County, NE, Dundy County, NE, Frontier County, NE, Furnas County, NE, Gosper County, NE, Hayes County, NE, Hitchcock County, NE, Hooker County, NE, Keya Paha County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Perkins County, NE, Red Willow County, NE, Rock County, NE, Thomas County, NE, Mellette County, SD, Todd County, SD, Tripp County, SD
The radar
The North Platte radar (KLNX), 51 km from the middle of the area, began a volume at 01:11 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
- 70%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 60%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 23, 8:25 PM CDT | Severe Thunderstorm Warning | GLD | Cheyenne, Sherman | 50 min |
| May 23, 8:50 PM CDT | Severe Thunderstorm Warning | GLD | Cheyenne, Rawlins, Sherman, Thomas, Wallace | 55 min |
| May 23, 9:11 PM CDT | Severe Thunderstorm Warning | LBF | Brown, Cherry, Keya Paha | 49 min |
| May 23, 9:13 PM CDT | Severe Thunderstorm Warning | GLD | Cheyenne, Rawlins | 32 min |
| May 23, 9:17 PM CDT | Severe Thunderstorm Warning | LBF | Chase, Hayes, Perkins | 43 min |
| May 23, 9:36 PM CDT | Flash Flood Warning | LBF | Keith, Perkins | 3 hr |
| May 23, 9:58 PM CDT | Severe Thunderstorm Warning | UNR | Tripp | 47 min |
| May 23, 10:30 PM CDT | Severe Thunderstorm Warning | LBF | Frontier, Lincoln | 45 min |
| May 23, 11:08 PM CDT | Severe Thunderstorm Warning | GID | Dawson, Gosper | 37 min |
| May 23, 11:12 PM CDT | Severe Thunderstorm Warning | GLD | Rawlins | 33 min |
| May 23, 11:29 PM CDT | Severe Thunderstorm Warning | GLD | Hitchcock, Red Willow | 36 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 00:00Z, 1.2 hours before the alert went out and 41 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
- 930 J/kg
- Mixed-layer CIN
- -36 J/kg
- Mixed-layer LCL
- 1216 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 161 m²/s²
- 0-3 km storm-relative helicity
- 229 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 7.0
The text
As transmitted.
521
WWUS20 KWNS 240110
SEL9
SPC WW 240110
KSZ000-NEZ000-SDZ000-240600-
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 199
NWS Storm Prediction Center Norman OK
810 PM CDT Sun May 23 2021
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Northwest Kansas
Central Nebraska
South Central South Dakota
* Effective this Sunday night and Monday morning from 810 PM
until 100 AM CDT.
* Primary threats include...
Scattered large hail likely with isolated very large hail events
to 2 inches in diameter possible
Scattered damaging wind gusts to 70 mph likely
A tornado or two possible
SUMMARY...A line of intense thunderstorms will track northeastward
across the watch area through the evening hours, posing a risk of
locally damaging wind gusts and hail.
The severe thunderstorm watch area is approximately along and 45
statute miles east and west of a line from 60 miles north northeast
of Valentine NE to 75 miles south of Goodland KS. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU9).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 196...WW 197...WW 198...
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
24035.
...HartSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 23, 7:32 PM CDT | Mesoscale Discussion | SPC | Morton | 118 min |
| May 23, 7:53 PM CDT | Mesoscale Discussion | SPC | Cheyenne, Sherman | 67 min |
| May 23, 9:56 PM CDT | Mesoscale Discussion | SPC | Cheyenne, Decatur, Logan, Rawlins, Sheridan, Sherman and 2 more | 2 hr |
| May 24, 1:00 PM CDT | Mesoscale Discussion | SPC | Finney, Gove, Grant, Gray, Greeley, Hamilton and 12 more | 2 hr |
| May 24, 1:29 PM CDT | Tornado Watch | SPC | Cheyenne, Decatur, Finney, Gove, Graham, Grant and 18 more | 9 hr |
| May 24, 3:42 PM CDT | Mesoscale Discussion | SPC | Gove, Logan, Rawlins, Sheridan, Thomas | 63 min |
| May 24, 5:37 PM CDT | Mesoscale Discussion | SPC | Decatur, Finney, Gove, Grant, Hamilton, Kearny and 7 more | 113 min |
| May 24, 6:39 PM CDT | Mesoscale Discussion | SPC | Decatur, Norton | 36 min |
| May 23, 8:22 PM CDT | Mesoscale Discussion | SPC | Campbell, Corson, Dewey, Potter, Stanley, Sully and 1 more | 53 min |
Nearby
Severe Thunderstorm Watches in Nebraska, 2021Severe Thunderstorm Watches in Kansas, 2021Severe Thunderstorm Watches in South Dakota, 2021Every severe thunderstorm watch in 2021
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.