Alert archive / Iowa / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 107, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Aug 27, 2021, 8:15 PM CDT for Cerro Gordo County, Worth County, Iowa. It was in force for 30 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Aug 27, 2021, 8:15 PM CDT (01:15 UTC)
- Expired
- Aug 27, 2021, 8:45 PM CDT
- In force
- 30 min
- Issued by
- NWS Des Moines, IA
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 60.0 mph
Counties Cerro Gordo County, IA, Worth County, IA
The radar
The La Crosse radar (KARX), 162 km from the middle of the area, began a volume at 01:15 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 watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 27, 5:15 PM CDT | Tornado Watch | SPC | 6 hr |
The nearest sounding before it
Minneapolis, MN (KMPX), launched 00:00Z, 1.3 hours before the alert went out and 172 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
- 652 J/kg
- Mixed-layer CIN
- -66 J/kg
- Mixed-layer LCL
- 643 m above ground
- 0-6 km bulk shear
- 45 kt
- 0-1 km storm-relative helicity
- 140 m²/s²
- 0-3 km storm-relative helicity
- 175 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 3.5
The text
As transmitted.
260
WUUS53 KDMX 280115
SVRDMX
IAC033-195-280145-
/O.NEW.KDMX.SV.W.0107.210828T0115Z-210828T0145Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
815 PM CDT Fri Aug 27 2021
The National Weather Service in Des Moines has issued a
* Severe Thunderstorm Warning for...
Eastern Worth County in north central Iowa...
Northeastern Cerro Gordo County in north central Iowa...
* Until 845 PM CDT.
* At 814 PM CDT, a severe thunderstorm was located 7 miles southwest
of St. Ansgar, or 11 miles west of Osage, moving northeast at 25
mph.
HAZARD...60 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect wind damage
to roofs, siding, and trees.
* This severe thunderstorm will remain over mainly rural areas of
eastern Worth and northeastern Cerro Gordo Counties, including the
following locations... Grafton, Bolan, Kensett, Plymouth and Rock
Falls.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A Tornado Watch remains in effect until 1100 PM CDT for north central
Iowa.
For your protection move to an interior room on the lowest floor of a
building.
A Tornado Watch remains in effect until 1100 PM CDT for north central
Iowa.
&&
LAT...LON 4334 9302 4321 9303 4321 9316 4340 9325
4346 9312 4347 9303
TIME...MOT...LOC 0114Z 238DEG 23KT 4331 9304
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
REV2 follow-up statements
294
WWUS53 KDMX 280128
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
828 PM CDT Fri Aug 27 2021
IAC033-195-280145-
/O.CON.KDMX.SV.W.0107.000000T0000Z-210828T0145Z/
Worth IA-Cerro Gordo IA-
828 PM CDT Fri Aug 27 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 845 PM CDT
FOR EASTERN WORTH AND NORTHEASTERN CERRO GORDO COUNTIES...
At 828 PM CDT, a severe thunderstorm was located near St. Ansgar, or
10 miles southeast of Northwood, moving northeast at 20 mph.
HAZARD...60 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect wind damage to
roofs, siding, and trees.
Locations impacted include...
Manly, Plymouth, Kensett, Grafton and Bolan.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A Tornado Watch remains in effect until 1100 PM CDT for north central
Iowa.
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4323 9303 4325 9318 4340 9325 4346 9312
4347 9303 4334 9302
TIME...MOT...LOC 0128Z 228DEG 18KT 4335 9304
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
REV836
WWUS53 KDMX 280142
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
842 PM CDT Fri Aug 27 2021
IAC033-195-280150-
/O.EXP.KDMX.SV.W.0107.000000T0000Z-210828T0145Z/
Worth IA-Cerro Gordo IA-
842 PM CDT Fri Aug 27 2021
...THE SEVERE THUNDERSTORM WARNING FOR EASTERN WORTH AND NORTHEASTERN
CERRO GORDO COUNTIES WILL EXPIRE AT 845 PM CDT...
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.
Heavy rain is likely with this thunderstorm.
A Tornado Watch remains in effect until 1100 PM CDT for north central
Iowa.
LAT...LON 4323 9303 4325 9318 4340 9325 4346 9312
4347 9303 4334 9302
TIME...MOT...LOC 0140Z 238DEG 23KT 4339 9296
$$
REVThe office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 27, 7:10 PM CDT | Severe Thunderstorm Warning | DMX | Cerro Gordo, Worth | 65 min |
| Aug 27, 8:21 PM CDT | Flash Flood Warning | DMX | Cerro Gordo, Hancock, Winnebago, Worth | 6 hr |
| Aug 28, 10:17 AM CDT | River Flood Warning | DMX | Black Hawk, Bremer, Butler | 3 days |
| Aug 28, 10:17 AM CDT | River Flood Warning | DMX | Black Hawk | 4 days |
Nearby
Severe Thunderstorm Warnings in Iowa, 2021Every severe thunderstorm warning 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.