Alert archive / Nebraska / Mesoscale Discussions in 2021
Mesoscale Discussion 697
The Storm Prediction Center issued this mesoscale discussion at May 21, 2021, 6:30 PM MDT for 4 states. It was in force for 90 min.
The area
The outline as issued.
The facts
- Issued
- May 21, 2021, 6:30 PM MDT (00:30 UTC)
- Expired
- May 21, 2021, 8:00 PM MDT
- In force
- 90 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 192
All 30 counties
Cheyenne County, CO, Elbert County, CO, Kit Carson County, CO, Lincoln County, CO, Logan County, CO, Morgan County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO, Yuma County, CO, Cheyenne County, KS, Sherman County, KS, Arthur County, NE, Box Butte County, NE, Chase County, NE, Cherry County, NE, Cheyenne County, NE, Deuel County, NE, Dundy County, NE, Garden County, NE, Grant County, NE, Hooker County, NE, Keith County, NE, McPherson County, NE, Morrill County, NE, Perkins County, NE, Sheridan County, NE, Bennett County, SD, Oglala Lakota County, SD, Todd County, SD
The radar
The Goodland radar (KGLD), 162 km from the middle of the area, began a volume at 00:34 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 nearest sounding before it
Denver, CO (KDNR), launched 00:00Z, 0.5 hours before the alert went out and 83 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 3010 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 17 m²/s²
- 0-3 km storm-relative helicity
- 163 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
874 ACUS11 KWNS 220031 SWOMCD SPC MCD 220030 SDZ000-NEZ000-KSZ000-COZ000-220200- Mesoscale Discussion 0697 NWS Storm Prediction Center Norman OK 0730 PM CDT Fri May 21 2021 Areas affected...Central High Plains Concerning...Severe Thunderstorm Watch 192... Valid 220030Z - 220200Z The severe weather threat for Severe Thunderstorm Watch 192 continues. SUMMARY...Severe threat continues across the central High Plains, especially from eastern Colorado into the Nebraska Panhandle. Hail remains the primary threat. DISCUSSION...Largely meridional deep-layer flow continues across the central High Plains this evening. This flow regime is responsible for a steep lapse-rate plume extending across eastern NM/CO into western NE. Scattered thunderstorms have formed along the western edge of higher PW along a low-level confluence zone as surface parcels reached convective temperatures. Much of this activity is producing at least marginally severe hail, though severe hail has been noted across the NE Panhandle with storms that have now lifted north of a well-defined surface front, and are now elevated as they skirt southeast of the Black Hills region. Given the deep southerly flow, greatest concentration of convection will extend along a corridor from eastern CO into the NE Panhandle, then into southwestern portions of SD north of a sharp cold front. Hail remains the primary risk. ..Darrow.. 05/22/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LBF...UNR...GLD...PUB...BOU...CYS... LAT...LON 38580459 43490284 43490005 38600200 38580459
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 22, 10:51 AM MDT | Mesoscale Discussion | SPC | Adams, Arapahoe, Crowley, Denver, Douglas, Elbert and 8 more | 114 min |
| May 22, 12:20 PM MDT | Tornado Watch | SPC | Adams, Arapahoe, Bent, Cheyenne, Crowley, Denver and 17 more | 8 hr |
| May 22, 1:34 PM MDT | Mesoscale Discussion | SPC | Phillips, Sedgwick, Washington | 116 min |
| May 22, 4:51 PM MDT | Mesoscale Discussion | SPC | Bent, Cheyenne, Crowley, Elbert, Kiowa, Kit Carson and 10 more | 114 min |
| May 22, 5:31 PM MDT | Mesoscale Discussion | SPC | Phillips, Sedgwick | 119 min |
| May 22, 2:55 PM MDT | Severe Thunderstorm Watch | SPC | Cheyenne, Rawlins, Sherman, Thomas | 5 hr |
| May 21, 9:04 PM MDT | Mesoscale Discussion | SPC | Fall River, Haakon, Jackson, Oglala Lakota | 86 min |
Nearby
Mesoscale Discussions in Nebraska, 2021Mesoscale Discussions in Colorado, 2021Mesoscale Discussions in South Dakota, 2021Every mesoscale discussion 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.