Alert archive / Iowa / Severe Thunderstorm Warnings in 2026
Severe Thunderstorm Warning 170, NWS La Crosse, WI
NWS La Crosse, WI issued this severe thunderstorm warning at Aug 11, 2026, 7:07 AM CDT for 6 counties in Iowa. It was in force for 50 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Aug 11, 2026, 7:07 AM CDT (12:07 UTC)
- Expired
- Aug 11, 2026, 7:57 AM CDT
- In force
- 50 min
- Issued by
- NWS La Crosse, WI
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 60.0 mph
Counties Allamakee County, IA, Chickasaw County, IA, Clayton County, IA, Fayette County, IA, Howard County, IA, Winneshiek County, IA
The radar
The La Crosse radar (KARX), 94 km from the middle of the area, began a volume at 12:09 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 nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 0.1 hours before the alert went out and 200 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
- 4268 J/kg
- Mixed-layer CIN
- -76 J/kg
- Mixed-layer LCL
- 891 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 136 m²/s²
- 0-3 km storm-relative helicity
- 153 m²/s²
- Significant tornado parameter
- 2.1
- Supercell composite
- 9.5
The office that day
Everything else NWS La Crosse, WI issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 11, 1:41 AM CDT | Special Weather Statement | ARX | Grant | 19 min |
| Aug 11, 7:37 AM CDT | Severe Thunderstorm Warning | ARX | Grant | 54 min |
| Aug 11, 6:51 AM CDT | Special Weather Statement | ARX | Chickasaw, Fayette, Floyd | 24 min |
| Aug 11, 6:56 AM CDT | Severe Thunderstorm Warning | ARX | Fayette | 34 min |
| Aug 11, 7:24 AM CDT | Areal Flood Advisory | ARX | Chickasaw, Floyd | 3 hr |
| Aug 11, 7:30 AM CDT | Severe Thunderstorm Warning | ARX | Allamakee, Winneshiek | 15 min |
Nearby
Severe Thunderstorm Warnings in Iowa, 2026Every severe thunderstorm warning in 2026
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.