Alert archive / Nebraska / Mesoscale Discussions in 2021
Mesoscale Discussion 714
The Storm Prediction Center issued this mesoscale discussion at May 23, 2021, 4:37 PM MDT for 9 counties in Colorado; Cheyenne County, Sherman County, Kansas; 13 counties in Nebraska. It was in force for 113 min.
The area
The outline as issued.
The facts
- Issued
- May 23, 2021, 4:37 PM MDT (22:37 UTC)
- Expired
- May 23, 2021, 6:30 PM MDT
- In force
- 113 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 196
All 24 counties
Cheyenne County, CO, Kiowa County, CO, Kit Carson County, CO, Lincoln County, CO, Logan 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, Cheyenne County, NE, Dawes County, NE, Deuel County, NE, Dundy County, NE, Garden County, NE, Grant County, NE, Keith County, NE, Morrill County, NE, Perkins County, NE, Sheridan County, NE
The radar
The Goodland radar (KGLD), 153 km from the middle of the area, began a volume at 22:37 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
Denver, CO (KDNR), launched 12:00Z, 10.6 hours before the alert went out and 79 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
- 1106 m above ground
- 0-6 km bulk shear
- 59 kt
- 0-1 km storm-relative helicity
- 73 m²/s²
- 0-3 km storm-relative helicity
- 177 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
359
ACUS11 KWNS 232238
SWOMCD
SPC MCD 232237
NEZ000-KSZ000-COZ000-240030-
Mesoscale Discussion 0714
NWS Storm Prediction Center Norman OK
0537 PM CDT Sun May 23 2021
Areas affected...Western Nebraska...northeast Colorado...far
northwest Kansas
Concerning...Tornado Watch 196...
Valid 232237Z - 240030Z
The severe weather threat for Tornado Watch 196 continues.
SUMMARY...Potential for tornadoes will increase into southwest
Nebraska and far northwest Kansas as low-level shear increases this
evening. The threat will be greatest with any remaining discrete
activity moving out of Colorado. Additional storms could develop
along the southern flank of the current activity and move into a
similarly favorable environment for tornadoes.
DISCUSSION...Ongoing convection within Tornado Watch 196 has trended
somewhat more linear in mode. A supercell moving north through Logan
County Colorado has a history of tornadoes and will move into
Nebraska over the next hour or so. This storm poses the greatest
tornado threat currently. Low-level shear is expected to increase
ahead of this activity with an increase in the low-level jet this
evening.
Farther south, cumulus have continue to deepen along the surface
trough. With some influence from the shortwave trough and an
increase in low-level convergence this evening, additional storm
development is possible. Again, these potential storms would also
move into a favorable environment for supercells with an attendant
risk for large hail, damaging winds, and tornadoes.
At present, storm coverage in the Nebraska Panhandle is sparse after
earlier storms. Given rain-cooled air roughly west of Alliance, NE,
additional severe storm development will likely occur east of that
longitude.
With time, activity is expected to congeal into a linear segments
with strong/severe wind gusts becoming the main hazard.
..Wendt.. 05/23/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LBF...GLD...PUB...BOU...CYS...
LAT...LON 41000342 41620372 42650351 42940285 42780205 41100124
40100112 39440146 38710212 38200282 38090327 38950368
40150377 41000342SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 23, 10:53 AM MDT | Mesoscale Discussion | SPC | Adams, Arapahoe, Broomfield, Denver, Douglas, Elbert and 6 more | 2 hr |
| May 23, 12:06 PM MDT | Tornado Watch | SPC | Adams, Arapahoe, Cheyenne, Crowley, Denver, Elbert and 11 more | 8 hr |
| May 23, 1:57 PM MDT | Mesoscale Discussion | SPC | Kit Carson, Logan, Morgan, Phillips, Sedgwick, Washington and 1 more | 2 hr |
| May 23, 2:41 PM MDT | Mesoscale Discussion | SPC | Baca, Bent, Prowers | 94 min |
| May 23, 4:07 PM MDT | Severe Thunderstorm Watch | SPC | Baca, Bent, Las Animas, Otero, Prowers | 7 hr |
Nearby
Mesoscale Discussions in Nebraska, 2021Mesoscale Discussions in Colorado, 2021Mesoscale Discussions in Kansas, 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.