Alert archive / Nebraska / Mesoscale Discussions in 2021
Mesoscale Discussion 1072
The Storm Prediction Center issued this mesoscale discussion at Jun 23, 2021, 10:12 PM CDT for 4 counties in Iowa; 45 counties in Nebraska. It was in force for 93 min.
The area
The outline as issued.
The facts
- Issued
- Jun 23, 2021, 10:12 PM CDT (03:12 UTC)
- Expired
- Jun 23, 2021, 11:45 PM CDT
- In force
- 93 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 306
All 49 counties
Harrison County, IA, Mills County, IA, Monona County, IA, Pottawattamie County, IA, Antelope County, NE, Blaine County, NE, Boone County, NE, Boyd County, NE, Brown County, NE, Buffalo County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Custer County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Garfield County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Holt County, NE, Howard County, NE, Knox County, NE, Lancaster County, NE, Loup County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Otoe County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Rock County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Sherman County, NE, Stanton County, NE, Thurston County, NE, Valley County, NE, Washington County, NE, Wayne County, NE, Wheeler County, NE, York County, NE
The radar
The Omaha radar (KOAX), 160 km from the middle of the area, began a volume at 03:15 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
Omaha, NE (KOAX), launched 00:00Z, 3.2 hours before the alert went out and 160 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
- 2039 J/kg
- Mixed-layer CIN
- -306 J/kg
- Mixed-layer LCL
- 1664 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 60 m²/s²
- 0-3 km storm-relative helicity
- 168 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.4
The text
As transmitted.
086
ACUS11 KWNS 240312
SWOMCD
SPC MCD 240312
IAZ000-NEZ000-SDZ000-240445-
Mesoscale Discussion 1072
NWS Storm Prediction Center Norman OK
1012 PM CDT Wed Jun 23 2021
Areas affected...portions of central and eastern Nebraska
Concerning...Severe Thunderstorm Watch 306...
Valid 240312Z - 240445Z
The severe weather threat for Severe Thunderstorm Watch 306
continues.
SUMMARY...Local severe risk continues across portions of Nebraska,
and should continue for several hours. New WW issuance is likely
across portions of central and eastern Nebraska, given the scheduled
24/04Z expiration of WW 306.
DISCUSSION...Latest radar loop shows a pair of severe storms exiting
Keya Paha County, and moving into Brown/Rock/Holt counties. The
stronger/lead supercell has begun a decided east-southeastward
advance, and this trend should continue over the next few hours as
the developing low-level jet begins to veer gradually more
southwesterly. With steep lapse rates aloft available to support
continued vigorous updrafts, and associated risk for large hail,
severe risk is forecast to continue across areas currently within
eastern portions of WW 306 as well as areas to the east and
southeast -- across eastern Nebraska.
Additionally, some upscale/linear growth is still anticipated, which
would suggest potential for an uptick in damaging wind potential.
HRRR runs continue to suggest such linear evolution, and given the
two observed/merging outflow boundaries across north-central
Nebraska -- one moving eastward (in conjunction with Cherry County
convection) and the other (emanating from the ongoing severe storms
farther east) shifting southward -- this would seem to remain a
reasonable expectation.
Given this ongoing/anticipated potential, a new WW will likely be
issued, prior to the expiration of WW 306, covering portions of
central and eastern Nebraska.
..Goss.. 06/24/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DMX...FSD...OAX...GID...LBF...
LAT...LON 42380017 42809988 43009887 42779705 42249585 41399521
40629571 40609748 40879923 41220011 42380017SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 23, 8:10 PM CDT | Mesoscale Discussion | SPC | Monona, Plymouth, Woodbury | 95 min |
| Jun 23, 10:37 PM CDT | Severe Thunderstorm Watch | SPC | Fremont, Harrison, Mills, Monona, Pottawattamie, Shelby and 1 more | 6 hr |
| Jun 24, 1:36 AM CDT | Mesoscale Discussion | SPC | Adams, Cass, Fremont, Harrison, Mills, Montgomery and 4 more | 114 min |
| Jun 24, 2:20 AM CDT | Severe Thunderstorm Watch | SPC | Adair, Adams, Audubon, Boone, Carroll, Cass and 15 more | 6 hr |
| Jun 24, 5:02 AM CDT | Mesoscale Discussion | SPC | Appanoose, Clarke, Davis, Decatur, Lucas, Madison and 8 more | 118 min |
| Jun 24, 3:44 PM CDT | Tornado Watch | SPC | Fremont, Page | 5 hr |
| Jun 24, 5:30 PM CDT | Mesoscale Discussion | SPC | Fremont, Page | 60 min |
| Jun 24, 6:19 PM CDT | Mesoscale Discussion | SPC | Appanoose, Clarke, Davis, Decatur, Lucas, Monroe and 3 more | 56 min |
| Jun 24, 6:33 PM CDT | Tornado Watch | SPC | Adams, Appanoose, Clarke, Davis, Decatur, Lucas and 6 more | 3 hr |
| Jun 24, 2:45 PM CDT | Mesoscale Discussion | SPC | Gage, Jefferson, Johnson, Pawnee, Richardson | 3 hr |
| Jun 24, 4:56 PM CDT | Severe Thunderstorm Watch | SPC | Dundy, Hitchcock | 6 hr |
Nearby
Mesoscale Discussions in Nebraska, 2021Mesoscale Discussions in Iowa, 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.