Alert archive / Iowa / Mesoscale Discussions in 2025
Mesoscale Discussion 1921
The Storm Prediction Center issued this mesoscale discussion at Aug 10, 2025, 4:59 AM CDT for 18 counties in Iowa. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Aug 10, 2025, 4:59 AM CDT (09:59 UTC)
- Expired
- Aug 10, 2025, 6:30 AM CDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 584
Counties Adair County, IA, Black Hawk County, IA, Boone County, IA, Butler County, IA, Cass County, IA, Dallas County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hardin County, IA, Jasper County, IA, Madison County, IA, Marshall County, IA, Polk County, IA, Story County, IA, Tama County, IA, Warren County, IA
The radar
The Des Moines radar (KDMX), 29 km from the middle of the area, began a volume at 10:01 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
Davenport, (KDVN), launched 00:00Z, 10.0 hours before the alert went out and 244 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
- 2514 J/kg
- Mixed-layer CIN
- -86 J/kg
- Mixed-layer LCL
- 1171 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- 40 m²/s²
- 0-3 km storm-relative helicity
- 236 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
719
ACUS11 KWNS 101000
SWOMCD
SPC MCD 100959
IAZ000-101130-
Mesoscale Discussion 1921
NWS Storm Prediction Center Norman OK
0459 AM CDT Sun Aug 10 2025
Areas affected...portions of central IA
Concerning...Severe Thunderstorm Watch 584...
Valid 100959Z - 101130Z
The severe weather threat for Severe Thunderstorm Watch 584
continues.
SUMMARY...Isolated strong to severe wind gusts remain possible
across central Iowa.
DISCUSSION...A cluster of storms will continue to track northeast
across central Iowa this morning. Overall radar presentation has
become somewhat disorganized, but a corridor of 60-70 kt velocity
signatures aloft are still noted to the west of the Des Moines
vicinity. Instability decreases gradually with northeast extent, and
stronger effective shear magnitudes remain displaced to the north.
While severe gusts are possible over the next couple of hours, the
expectation is that a gradual weakening trend will continue as
convection develops northeast.
..Leitman.. 08/10/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DVN...ARX...DMX...OAX...
LAT...LON 42049209 41559278 41279360 41059453 41129495 41339497
41979471 42619336 42839257 42659203 42049209
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 INSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 9, 8:46 PM CDT | Severe Thunderstorm Watch | SPC | Fremont, Mills, Montgomery, Page, Pottawattamie | 8 hr |
| Aug 10, 1:44 AM CDT | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Boone, Cass, Clarke and 23 more | 2 hr |
| Aug 10, 2:51 AM CDT | Severe Thunderstorm Watch | SPC | Adair, Adams, Appanoose, Audubon, Boone, Butler and 29 more | 4 hr |
Nearby
Mesoscale Discussions in Iowa, 2025Every mesoscale discussion in 2025
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.