Alert archive / Nebraska / Mesoscale Discussions in 2021
Mesoscale Discussion 1071
The Storm Prediction Center issued this mesoscale discussion at Jun 23, 2021, 8:10 PM CDT for Monona County, Plymouth County, Woodbury County, Iowa; 28 counties in Nebraska; 11 counties in South Dakota. It was in force for 95 min.
The area
The outline as issued.
The facts
- Issued
- Jun 23, 2021, 8:10 PM CDT (01:10 UTC)
- Expired
- Jun 23, 2021, 9:45 PM CDT
- In force
- 95 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 306
All 42 counties
Monona County, IA, Plymouth County, IA, Woodbury County, IA, Antelope County, NE, Blaine County, NE, Boone County, NE, Boyd County, NE, Brown County, NE, Burt County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Garfield County, NE, Greeley County, NE, Holt County, NE, Keya Paha County, NE, Knox County, NE, Loup County, NE, Madison County, NE, Nance County, NE, Pierce County, NE, Platte County, NE, Rock County, NE, Stanton County, NE, Thurston County, NE, Valley County, NE, Wayne County, NE, Wheeler County, NE, Bon Homme County, SD, Charles Mix County, SD, Clay County, SD, Davison County, SD, Douglas County, SD, Gregory County, SD, Hutchinson County, SD, Lincoln County, SD, Turner County, SD, Union County, SD, Yankton County, SD
The radar
The Sioux Falls radar (KFSD), 171 km from the middle of the area, began a volume at 01:09 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, 1.2 hours before the alert went out and 198 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.
724
ACUS11 KWNS 240110
SWOMCD
SPC MCD 240110
IAZ000-NEZ000-SDZ000-240245-
Mesoscale Discussion 1071
NWS Storm Prediction Center Norman OK
0810 PM CDT Wed Jun 23 2021
Areas affected...parts of central and eastern
Nebraska...southeastern South Dakota...and far western Iowa
Concerning...Severe Thunderstorm Watch 306...
Valid 240110Z - 240245Z
The severe weather threat for Severe Thunderstorm Watch 306
continues.
SUMMARY...Storms increasing in coverage/intensity -- likely in
response to the developing low-level jet -- suggest increasing
severe potential over the next couple of hours. A new WW remains
likely to be needed east of ongoing activity.
DISCUSSION...After a brief decreasing trend in ongoing convection,
storms have begun to increase in both coverage and intensity once
again -- mainly across north-central Nebraska and into south-central
and southeastern South Dakota. The convective uptick is apparently
in response to increasing QG forcing, as a subtle feature aloft
shifts into the Plains, along with associated/accompanying low-level
jet increase. While low-level capping hindered more widespread
diurnal surface-based activity, continued increases in slightly
elevated but robust convection are expected. As convection shifts
eastward/southeastward with time, a new WW east of WW 306 remains a
likelihood this evening.
..Goss.. 06/24/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DMX...FSD...OAX...ABR...GID...LBF...UNR...
LAT...LON 41479987 42870055 43549929 43679875 43729817 43469656
42499560 41779571 41509690 41309875 41479987SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 23, 10:12 PM CDT | Mesoscale Discussion | SPC | Harrison, Mills, Monona, Pottawattamie | 93 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 |
| Jun 24, 3:37 PM CDT | Mesoscale Discussion | SPC | Lawrence | 83 min |
Nearby
Mesoscale Discussions in Nebraska, 2021Mesoscale Discussions in South Dakota, 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.