Alert archive / Iowa / Mesoscale Discussions in 2021
Mesoscale Discussion 1028
The Storm Prediction Center issued this mesoscale discussion at Jun 20, 2021, 3:37 AM CDT for 18 counties in Iowa; 11 counties in Missouri. It was in force for 113 min.
The area
The outline as issued.
The facts
- Issued
- Jun 20, 2021, 3:37 AM CDT (08:37 UTC)
- Expired
- Jun 20, 2021, 5:30 AM CDT
- In force
- 113 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 292
All 29 counties
Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Cass County, IA, Clarke County, IA, Dallas County, IA, Decatur County, IA, Guthrie County, IA, Lucas County, IA, Madison County, IA, Montgomery County, IA, Ringgold County, IA, Shelby County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Wayne County, IA, Adair County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Mercer County, MO, Nodaway County, MO, Putnam County, MO, Sullivan County, MO, Worth County, MO
The radar
The Des Moines radar (KDMX), 123 km from the middle of the area, began a volume at 08:39 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
Omaha, NE (KOAX), launched 00:00Z, 8.6 hours before the alert went out and 195 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
- 2439 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 23 m²/s²
- 0-3 km storm-relative helicity
- 69 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
193
ACUS11 KWNS 200837
SWOMCD
SPC MCD 200837
MOZ000-IAZ000-201030-
Mesoscale Discussion 1028
NWS Storm Prediction Center Norman OK
0337 AM CDT Sun Jun 20 2021
Areas affected...Southern Iowa...Northern Missouri
Concerning...Severe Thunderstorm Watch 292...
Valid 200837Z - 201030Z
The severe weather threat for Severe Thunderstorm Watch 292
continues.
SUMMARY...The severe threat across WW 292 is expected to become very
isolated over the next hour. A new downstream weather watch will not
be needed due to the marginal nature of the threat.
DISCUSSION...The latest radar imagery shows a
north-northwest/south-southeast oriented band of strong
thunderstorms located in southwest Iowa and northwest Missouri. This
band is moving eastward along a quasi-stationary front that extends
from southern Iowa into northern Illinois. To the south of the
front, the RAP is showing an east-to-west corridor of moderate
instability. This combined with about 35 kt of 0-6 km shear, evident
on regional WSR-88D VWPs should sustain an isolated severe threat
over the next hour. However, the threat should become increasingly
marginal as the storms move to the east of the strongest
instability. For this reason, a new weather watch will not be needed
downstream of WW 292, and the current watch will be allowed to
expire at 5 am CDT.
..Broyles/Edwards.. 06/20/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DMX...EAX...OAX...
LAT...LON 39819329 39739420 39799458 40109485 40629500 41309530
41729546 41859477 41789396 41519319 40209255 39819329SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 19, 11:09 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Audubon, Cass, Fremont, Guthrie and 10 more | 96 min |
| Jun 19, 11:59 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Audubon, Cass, Fremont, Harrison, Mills and 5 more | 4 hr |
| Jun 20, 10:57 AM CDT | Mesoscale Discussion | SPC | Des Moines, Henry, Lee, Louisa, Scott | 2 hr |
| Jun 20, 1:10 PM CDT | Mesoscale Discussion | SPC | Boone, Butler, Calhoun, Cerro Gordo, Emmet, Floyd and 17 more | 95 min |
| Jun 20, 1:42 PM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Black Hawk, Bremer, Butler, Calhoun, Cerro Gordo and 23 more | 7 hr |
| Jun 20, 2:02 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Boone, Cass, Clarke and 22 more | 118 min |
| Jun 20, 4:01 PM CDT | Severe Thunderstorm Watch | SPC | Appanoose, Benton, Boone, Buchanan, Cedar, Clarke and 35 more | 7 hr |
| Jun 20, 5:22 PM CDT | Mesoscale Discussion | SPC | Allamakee, Black Hawk, Bremer, Buchanan, Butler, Chickasaw and 9 more | 113 min |
| Jun 20, 6:56 PM CDT | Mesoscale Discussion | SPC | Appanoose, Clarke, Davis, Decatur, Des Moines, Henry and 15 more | 2 hr |
| Jun 19, 9:49 PM CDT | Mesoscale Discussion | SPC | Audrain, Chariton, Lincoln, Macon, Monroe, Montgomery and 7 more | 56 min |
Nearby
Mesoscale Discussions in Iowa, 2021Mesoscale Discussions in Missouri, 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.