Alert archive / Iowa / Tornado Warnings in 2012
Tornado Warning 9, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this tornado warning at Apr 21, 2012, 4:21 PM CDT for Clay County, Iowa. It was in force for 24 min. 3 reports 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
- Apr 21, 2012, 4:21 PM CDT (21:21 UTC)
- Expired
- Apr 21, 2012, 4:45 PM CDT
- In force
- 24 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
County Clay County, IA
The radar
The Sioux Falls radar (KFSD), 145 km from the middle of the area, began a volume at 21:24 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 |
|---|---|---|---|
| Apr 21, 4:27 PM CDT | TORNADO | 3 Sse Spencer, IA | ROPE TORNADO ON THE GROUND FOR ABOUT 5 MINUTES |
| Apr 21, 4:40 PM CDT | HAIL 0.88 | 1 E Spencer, IA | LOTS OF NICKEL SIZED HAIL |
| Apr 21, 4:43 PM CDT | TORNADO | 10 Sse Dickens, IA | ON THE GROUND FOR ABOUT ONE MINUTE |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Omaha, NE (KOAX), launched 12:00Z, 9.4 hours before the alert went out and 224 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1613 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 110 m²/s²
- 0-3 km storm-relative helicity
- 269 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
854
WFUS53 KFSD 212121
TORFSD
IAC041-212145-
/O.NEW.KFSD.TO.W.0009.120421T2121Z-120421T2145Z/
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
421 PM CDT SAT APR 21 2012
THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A
* TORNADO WARNING FOR...
CLAY COUNTY IN NORTHWEST IOWA...
* UNTIL 445 PM CDT
* AT 421 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
TRACKING A CONFIRMED TORNADO NEAR SPENCER. DOPPLER RADAR SHOWED
THIS TORNADO MOVING SOUTHEAST AT 35 MPH.
* THE TORNADO WILL AFFECT MAINLY RURAL AREAS OF CLAY COUNTY...
INCLUDING THE FOLLOWING LOCATIONS DICKENS AND GILLETT GROVE.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.
&&
LAT...LON 4292 9494 4317 9532 4326 9526 4326 9520
4317 9491 4295 9491
TIME...MOT...LOC 2121Z 306DEG 28KT 4316 9521
$$
HANKO1 follow-up statement
473
WWUS53 KFSD 212136
SVSFSD
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
436 PM CDT SAT APR 21 2012
IAC041-212145-
/O.CON.KFSD.TO.W.0009.000000T0000Z-120421T2145Z/
CLAY IA-
436 PM CDT SAT APR 21 2012
...A TORNADO WARNING REMAINS IN EFFECT FOR EASTERN CLAY COUNTY UNTIL
445 PM CDT...
AT 435 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A SEVERE THUNDERSTORM WITH A HISTORY OF OF PRODUCING A TORNADO. THIS
DANGEROUS STORM WAS LOCATED NEAR SPENCER...MOVING SOUTHEAST AT 30
MPH.
AT 427 PM CDT A ROPE TORNADO 3 MILES SOUTH SOUTHEAST OF SPENCER
LIFTED FROM THE GROUND AND A SECOND FUNNEL WAS DEVELOPING.
THIS TORNADO WILL AFFECT MAINLY RURAL AREAS OF EASTERN CLAY COUNTY...
INCLUDING THE FOLLOWING LOCATIONS GILLETT GROVE.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.
&&
LAT...LON 4292 9494 4312 9523 4323 9515 4317 9491
4295 9491
TIME...MOT...LOC 2135Z 303DEG 27KT 4309 9508
$$
HANKOThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 21, 4:38 PM CDT | Tornado Warning | FSD | Dickinson | 37 min |
| Apr 21, 4:45 PM CDT | Tornado Warning | FSD | Clay | 14 min |
Nearby
Tornado Warnings in Iowa, 2012Every tornado warning in 2012Tornadoes in 2012
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.