Alert archive / Iowa / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 92, NWS La Crosse, WI
NWS La Crosse, WI issued this severe thunderstorm warning at Aug 27, 2021, 6:52 PM CDT for Allamakee County, Fayette County, Winneshiek County, Iowa. It was in force for 38 min. 1 report came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 27, 2021, 6:52 PM CDT (23:52 UTC)
- Expired
- Aug 27, 2021, 7:30 PM CDT
- In force
- 38 min
- Issued by
- NWS La Crosse, WI
- Area
- Storm-based polygon
- Tornado
- Possible
- Hail
- 1.0 in
- Wind
- 60.0 mph
Counties Allamakee County, IA, Fayette County, IA, Winneshiek County, IA
The radar
The La Crosse radar (KARX), 87 km from the middle of the area, began a volume at 23:51 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 27, 6:55 PM CDT | TSTM WND DMG | Spillville, IA | LOTS OF POWER OUTAGES ACROSS THE SOUTHERN PART OF THE COUNTY FROM WINDS CAUSING DOWNED POWER LINES TO LIGHTNING STRIKES. COMMUNITIES IMPACTED INCLUDE SPILLVILLE, FORT ATKINSON, OSSIAN AND CALMAR. HEAVY RAIN ALSO CREATED LOTS OF STANDING WATER IN CALMAR. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
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
Davenport, (KDVN), launched 12:00Z, 11.9 hours before the alert went out and 202 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
- 358 J/kg
- Mixed-layer CIN
- -231 J/kg
- Mixed-layer LCL
- 1213 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 144 m²/s²
- 0-3 km storm-relative helicity
- 84 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
098
WUUS53 KARX 272352
SVRARX
IAC005-065-191-280030-
/O.NEW.KARX.SV.W.0092.210827T2352Z-210828T0030Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service La Crosse WI
652 PM CDT Fri Aug 27 2021
The National Weather Service in La Crosse has issued a
* Severe Thunderstorm Warning for...
North central Fayette County in northeastern Iowa...
Southwestern Allamakee County in northeastern Iowa...
Southern Winneshiek County in northeastern Iowa...
* Until 730 PM CDT.
* At 651 PM CDT, a severe thunderstorm was located over Calmar, or 9
miles southwest of Decorah, moving east at 40 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...
Decorah, Waukon, Postville, Calmar, Ossian, Spillville, Fort
Atkinson, Castalia, and Jackson Junction.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A Tornado Watch remains in effect until 1100 PM CDT for northeastern
Iowa.
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4307 9206 4328 9208 4333 9137 4309 9134
TIME...MOT...LOC 2351Z 264DEG 36KT 4317 9187
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Skow1 follow-up statement
974
WWUS53 KARX 280011
SVSARX
Severe Weather Statement
National Weather Service La Crosse WI
711 PM CDT Fri Aug 27 2021
IAC065-280020-
/O.CAN.KARX.SV.W.0092.000000T0000Z-210828T0030Z/
Fayette IA-
711 PM CDT Fri Aug 27 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL FAYETTE COUNTY
IS CANCELLED...
The severe thunderstorm which prompted the warning has moved out of
the warned area. Therefore, the warning has been cancelled.
A Tornado Watch remains in effect until 1100 PM CDT for northeastern
Iowa.
LAT...LON 4308 9187 4323 9186 4329 9136 4309 9134
TIME...MOT...LOC 0010Z 266DEG 30KT 4316 9173
$$
IAC005-191-280030-
/O.CON.KARX.SV.W.0092.000000T0000Z-210828T0030Z/
Allamakee IA-Winneshiek IA-
711 PM CDT Fri Aug 27 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM CDT
FOR SOUTHWESTERN ALLAMAKEE AND SOUTHEASTERN WINNESHIEK COUNTIES...
At 710 PM CDT, a severe thunderstorm was located over Ossian, or 10
miles south of Decorah, moving east at 35 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...
Waukon, Postville, Calmar, Ossian, Castalia, Volney, County Roads X
16 And B 38, State Road 76 And County X 16, Nordness, Maud, Ludlow,
County Road W 46 And Centennial Road, County Roads X 16 And W 48,
Frankville, State Road 9 And Frankville Road, State Road 51 And
County W 48, Rossville, County Roads A 52 And W 60 and Festina.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A Tornado Watch remains in effect until 1100 PM CDT for northeastern
Iowa.
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4308 9187 4323 9186 4329 9136 4309 9134
TIME...MOT...LOC 0010Z 266DEG 30KT 4316 9173
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
SkowThe office that day
Everything else NWS La Crosse, WI issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 27, 1:51 AM CDT | Flash Flood Warning | ARX | Howard, Mitchell | 4 hr |
| Aug 27, 3:33 AM CDT | Flash Flood Warning | ARX | Howard, Mitchell, Winneshiek | 4 hr |
| Aug 27, 9:42 AM CDT | River Flood Warning | ARX | Winneshiek | 60 hr |
| Aug 27, 3:24 PM CDT | Special Weather Statement | ARX | Howard, Mitchell | 51 min |
| Aug 27, 5:34 PM CDT | Tornado Warning | ARX | Floyd | 41 min |
| Aug 27, 6:09 PM CDT | Tornado Warning | ARX | Chickasaw, Floyd | 51 min |
| Aug 27, 6:45 PM CDT | Tornado Warning | ARX | Chickasaw, Fayette | 45 min |
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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.