Alert archive / Iowa / Mesoscale Discussions in 2021
Mesoscale Discussion 1440
The Storm Prediction Center issued this mesoscale discussion at Aug 7, 2021, 11:19 PM CDT for 10 counties in Iowa; Doniphan County, Kansas; 6 counties in Missouri. It was in force for 86 min.
The area
The outline as issued.
The facts
- Issued
- Aug 7, 2021, 11:19 PM CDT (04:19 UTC)
- Expired
- Aug 8, 2021, 12:45 AM CDT
- In force
- 86 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 414
Counties Adair County, IA, Adams County, IA, Cass County, IA, Clarke County, IA, Madison County, IA, Montgomery County, IA, Page County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA, Doniphan County, KS, Andrew County, MO, Atchison County, MO, Gentry County, MO, Holt County, MO, Nodaway County, MO, Worth County, MO
The radar
The Des Moines radar (KDMX), 132 km from the middle of the area, began a volume at 04:20 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, 4.3 hours before the alert went out and 148 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
- 2933 J/kg
- Mixed-layer CIN
- -124 J/kg
- Mixed-layer LCL
- 1327 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 149 m²/s²
- 0-3 km storm-relative helicity
- 195 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 3.3
The text
As transmitted.
248
ACUS11 KWNS 080419
SWOMCD
SPC MCD 080419
IAZ000-MOZ000-KSZ000-NEZ000-080545-
Mesoscale Discussion 1440
NWS Storm Prediction Center Norman OK
1119 PM CDT Sat Aug 07 2021
Areas affected...Parts of northeastern Kansas...northwestern
Missouri....southeastern Nebraska and southwest Iowa
Concerning...Severe Thunderstorm Watch 414...
Valid 080419Z - 080545Z
The severe weather threat for Severe Thunderstorm Watch 414
continues.
SUMMARY...A small cluster of vigorous thunderstorm development could
still pose some risk for strong wind gusts near the western
Missouri/Iowa border vicinity through Midnight-2 AM CDT, but this
risk may remain marginal and isolated enough that another severe
weather watch will not be necessary.
DISCUSSION...Based on recent radar trends, inhibition associated
with elevated mixed-layer air, even to the north of the Interstate
70 corridor, has been sufficient to suppress maintenance of vigorous
thunderstorm development. Deep-layer shear may be too marginal as
well, while outflow from the earlier severe storm cluster across the
Omaha, NE area has also surged southeastward.
Intersecting outflow boundaries northwest through north of Falls
City, NE remain a focus for a relatively vigorous area of
thunderstorm development. This could still intensify some, with at
least some potential to organize and produce strong surface gusts
near the western Missouri/Iowa border vicinity, as a remnant MCV
approaches the Omaha area through 05-07Z. These trends will
continue to be monitored, but it is appearing less likely that a new
severe weather watch will be needed.
..Kerr.. 08/08/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DMX...EAX...OAX...TOP...
LAT...LON 41279517 41649480 41479375 40769377 40089436 39719518
40329565 41279517SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 7, 9:35 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Cass, Clarke, Decatur, Fremont and 7 more | 85 min |
| Aug 8, 5:04 PM CDT | Mesoscale Discussion | SPC | Buena Vista, Calhoun, Cherokee, Clay, Dickinson, Emmet and 11 more | 86 min |
| Aug 7, 8:20 PM CDT | Mesoscale Discussion | SPC | Barber, Clark, Comanche, Harper, Kiowa, Meade and 1 more | 55 min |
| Aug 7, 11:42 PM CDT | Mesoscale Discussion | SPC | Butler, Chase, Greenwood, Harper, Harvey, Lyon and 2 more | 93 min |
| Aug 8, 11:40 AM CDT | Mesoscale Discussion | SPC | Audrain, Boone, Callaway, Camden, Carter, Christian and 42 more | 3 hr |
| Aug 8, 12:44 PM CDT | Severe Thunderstorm Watch | SPC | Audrain, Bollinger, Boone, Butler, Callaway, Carter and 38 more | 7 hr |
| Aug 8, 3:00 PM CDT | Mesoscale Discussion | SPC | Audrain, Bollinger, Butler, Cape Girardeau, Carter, Crawford and 27 more | 2 hr |
| Aug 8, 5:47 PM CDT | Mesoscale Discussion | SPC | Cape Girardeau, Mississippi, New Madrid, Scott, Stoddard | 88 min |
Nearby
Mesoscale Discussions in Iowa, 2021Mesoscale Discussions in Missouri, 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.