Alert archive / Iowa / Tornado Warnings in 2011
Tornado Warning 7, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this tornado warning at Apr 9, 2011, 9:31 PM CDT for Plymouth County, Woodbury County, Iowa; Union County, South Dakota; Dakota County, Nebraska. It was in force for 29 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
- Apr 9, 2011, 9:31 PM CDT (02:31 UTC)
- Expired
- Apr 9, 2011, 10:00 PM CDT
- In force
- 29 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
Counties Plymouth County, IA, Woodbury County, IA, Dakota County, NE, Union County, SD
The radar
The Sioux Falls radar (KFSD), 114 km from the middle of the area, began a volume at 02:32 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 9, 9:50 PM CDT | HAIL 1.25 | 10 N Sioux City, IA |
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 |
|---|---|---|---|
| Apr 9, 5:48 PM CDT | Tornado Watch | SPC | 7 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 2.5 hours before the alert went out and 141 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
- 3327 J/kg
- Mixed-layer CIN
- -24 J/kg
- Mixed-layer LCL
- 1533 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- 270 m²/s²
- 0-3 km storm-relative helicity
- 403 m²/s²
- Significant tornado parameter
- 3.7
- Supercell composite
- 19.0
The text
As transmitted, in the capitals the NWS used until 2016.
603 WFUS53 KFSD 100231 TORFSD IAC149-193-NEC043-SDC127-100300- /O.NEW.KFSD.TO.W.0007.110410T0231Z-110410T0300Z/ BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE SIOUX FALLS SD 931 PM CDT SAT APR 9 2011 THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A * TORNADO WARNING FOR... SOUTH CENTRAL PLYMOUTH COUNTY IN NORTHWEST IOWA... NORTHWESTERN WOODBURY COUNTY IN NORTHWEST IOWA... NORTHEASTERN DAKOTA COUNTY IN NORTHEAST NEBRASKA... EXTREME SOUTHEASTERN UNION COUNTY IN SOUTHEAST SOUTH DAKOTA... * UNTIL 1000 PM CDT * AT 931 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED NEAR JACKSON...OR 9 MILES WEST OF SIOUX CITY...AND MOVING NORTHEAST AT 35 MPH. * THIS TORNADIC STORM WILL BE NEAR... STONE STATE PARK AND SIOUX CITY AROUND 940 PM CDT... HINTON AROUND 955 PM CDT... 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 4272 9636 4259 9625 4241 9653 4248 9663 TIME...MOT...LOC 0231Z 220DEG 32KT 4248 9652 $$ CJ
2 follow-up statements
943
WWUS53 KFSD 100244
SVSFSD
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
944 PM CDT SAT APR 9 2011
NEC043-SDC127-100254-
/O.CAN.KFSD.TO.W.0007.000000T0000Z-110410T0300Z/
DAKOTA NE-UNION SD-
944 PM CDT SAT APR 9 2011
...THE TORNADO WARNING FOR EXTREME SOUTHEASTERN UNION AND
NORTHEASTERN DAKOTA COUNTIES IS CANCELLED...
THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE WARNED
AREA.
LAT...LON 4254 9649 4256 9649 4272 9636 4259 9625
4250 9643
TIME...MOT...LOC 0244Z 220DEG 32KT 4257 9642
$$
IAC149-193-100300-
/O.CON.KFSD.TO.W.0007.000000T0000Z-110410T0300Z/
PLYMOUTH IA-WOODBURY IA-
944 PM CDT SAT APR 9 2011
...A TORNADO WARNING REMAINS IN EFFECT FOR EXTREME NORTHWESTERN
WOODBURY AND SOUTH CENTRAL PLYMOUTH COUNTIES UNTIL 1000 PM CDT...
AT 944 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED NEAR STONE STATE PARK...OR NEAR SIOUX CITY...MOVING
NORTHEAST AT 35 MPH.
THIS DANGEROUS STORM WILL BE NEAR...
HINTON AROUND 955 PM CDT...
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 4254 9649 4256 9649 4272 9636 4259 9625
4250 9643
TIME...MOT...LOC 0244Z 220DEG 32KT 4257 9642
$$
CJ926
WWUS53 KFSD 100256
SVSFSD
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
956 PM CDT SAT APR 9 2011
IAC149-193-100306-
/O.EXP.KFSD.TO.W.0007.000000T0000Z-110410T0300Z/
PLYMOUTH IA-WOODBURY IA-
956 PM CDT SAT APR 9 2011
...THE TORNADO WARNING FOR EXTREME NORTHWESTERN WOODBURY AND SOUTH
CENTRAL PLYMOUTH COUNTIES WILL EXPIRE AT 1000 PM CDT...
THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE
LIMITS...AND NO LONGER POSES AN IMMEDIATE THREAT TO LIFE OR PROPERTY.
LAT...LON 4254 9649 4256 9649 4272 9636 4259 9625
4250 9643
TIME...MOT...LOC 0256Z 220DEG 32KT 4265 9632
$$
CJThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 7:09 PM CDT | Severe Thunderstorm Warning | FSD | Ida, Woodbury | 36 min |
| Apr 9, 7:31 PM CDT | Tornado Warning | FSD | Ida | 29 min |
| Apr 9, 7:44 PM CDT | Severe Thunderstorm Warning | FSD | Ida | 31 min |
| Apr 9, 7:46 PM CDT | Severe Thunderstorm Warning | FSD | Cherokee, Ida, Woodbury | 29 min |
| Apr 9, 7:56 PM CDT | Tornado Warning | FSD | Ida | 34 min |
| Apr 9, 8:08 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Cherokee, Ida, Woodbury | 37 min |
| Apr 9, 8:11 PM CDT | Severe Thunderstorm Warning | FSD | Ida | 34 min |
| Apr 9, 8:19 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth, Woodbury | 41 min |
| Apr 9, 8:40 PM CDT | Severe Thunderstorm Warning | FSD | Cherokee | 35 min |
| Apr 9, 8:41 PM CDT | Severe Thunderstorm Warning | FSD | Ida | 19 min |
| Apr 9, 8:49 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista | 41 min |
| Apr 9, 8:55 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth, Woodbury | 35 min |
| Apr 9, 9:08 PM CDT | Severe Thunderstorm Warning | FSD | Cherokee | 37 min |
| Apr 9, 9:09 PM CDT | Tornado Warning | FSD | Buena Vista | 36 min |
| Apr 9, 9:15 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth, Sioux | 30 min |
| Apr 9, 9:17 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth, Woodbury | 43 min |
| Apr 9, 9:24 PM CDT | Severe Thunderstorm Warning | FSD | Cherokee, Plymouth, Woodbury | 36 min |
| Apr 9, 9:25 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista | 20 min |
| Apr 9, 9:36 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Cherokee, Clay | 39 min |
| Apr 9, 9:46 PM CDT | Tornado Warning | FSD | Buena Vista | 29 min |
| Apr 9, 9:48 PM CDT | Tornado Warning | FSD | Cherokee | 27 min |
| Apr 9, 9:58 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth | 32 min |
| Apr 9, 10:02 PM CDT | Tornado Warning | FSD | Buena Vista | 28 min |
| Apr 9, 10:09 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista | 36 min |
| Apr 9, 10:13 PM CDT | Tornado Warning | FSD | Buena Vista, Cherokee | 47 min |
| Apr 9, 10:24 PM CDT | Severe Thunderstorm Warning | FSD | Cherokee, O'Brien, Plymouth, Sioux | 36 min |
| Apr 9, 10:31 PM CDT | Tornado Warning | FSD | Cherokee | 29 min |
| Apr 9, 10:35 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Clay | 30 min |
| Apr 9, 10:50 PM CDT | Tornado Warning | FSD | Buena Vista, Cherokee | 40 min |
| Apr 9, 11:11 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Clay | 34 min |
| Apr 9, 11:27 PM CDT | Tornado Warning | FSD | Buena Vista, Clay | 18 min |
| Apr 9, 11:39 PM CDT | Tornado Warning | FSD | Clay | 21 min |
| Apr 10, 12:24 AM CDT | Severe Thunderstorm Warning | FSD | Woodbury | 36 min |
| Apr 10, 12:47 AM CDT | Severe Thunderstorm Warning | FSD | Cherokee, Ida | 28 min |
| Apr 9, 7:16 PM CDT | Severe Thunderstorm Warning | FSD | Hutchinson | 29 min |
| Apr 9, 7:38 PM CDT | Severe Thunderstorm Warning | FSD | Clay, Yankton | 26 min |
| Apr 9, 7:42 PM CDT | Severe Thunderstorm Warning | FSD | Davison, Hanson, Hutchinson | 33 min |
| Apr 9, 8:11 PM CDT | Severe Thunderstorm Warning | FSD | Lake, McCook, Miner, Minnehaha | 34 min |
| Apr 9, 8:45 PM CDT | Severe Thunderstorm Warning | FSD | Lake, McCook, Minnehaha, Moody | 45 min |
| Apr 9, 8:55 PM CDT | Severe Thunderstorm Warning | FSD | Brookings, Lake, Moody | 50 min |
| Apr 9, 9:17 PM CDT | Severe Thunderstorm Warning | FSD | Minnehaha, Moody | 43 min |
| Apr 9, 7:29 PM CDT | Severe Thunderstorm Warning | FSD | Dixon | 31 min |
| Apr 9, 7:57 PM CDT | Tornado Warning | FSD | Dakota, Dixon | 33 min |
| Apr 9, 8:34 PM CDT | Severe Thunderstorm Warning | FSD | Dakota, Dixon | 26 min |
Nearby
Tornado Warnings in Iowa, 2011Tornado Warnings in South Dakota, 2011Tornado Warnings in Nebraska, 2011Every tornado warning in 2011Tornadoes in 2011
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.