Alert archive / Iowa / Tornado Warnings in 2021
Tornado Warning 28, NWS Omaha, NE
NWS Omaha, NE issued this tornado warning at Dec 15, 2021, 4:46 PM CST for Pottawattamie County, Shelby County, Iowa. It was in force for 20 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
- Dec 15, 2021, 4:46 PM CST (22:46 UTC)
- Expired
- Dec 15, 2021, 5:06 PM CST
- In force
- 20 min
- Issued by
- NWS Omaha, NE
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 0.75 in
Counties Pottawattamie County, IA, Shelby County, IA
The radar
The Omaha radar (KOAX), 102 km from the middle of the area, began a volume at 22:48 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 |
|---|---|---|---|
| Dec 15, 4:50 PM CST | TSTM WND GST 67 | 3 Ene Avoca, IA | MESONET STATION RAVI4 AVOCA (I-80). |
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 |
|---|---|---|---|
| Dec 15, 1:23 PM CST | Tornado Watch | SPC | 7 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 12:00Z, 10.8 hours before the alert went out and 103 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
- 2165 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 346 m²/s²
- 0-3 km storm-relative helicity
- 384 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
949
WFUS53 KOAX 152246
TOROAX
IAC155-165-152330-
/O.NEW.KOAX.TO.W.0028.211215T2246Z-211215T2330Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Omaha/Valley Nebraska
446 PM CST Wed Dec 15 2021
The National Weather Service in Omaha has issued a
* Tornado Warning for...
Northeastern Pottawattamie County in southwestern Iowa...
Southeastern Shelby County in southwestern Iowa...
* Until 530 PM CST.
* At 446 PM CST, a severe thunderstorm capable of producing a tornado
was located 8 miles east of Oakland, or 12 miles west of Atlantic,
moving northeast at 85 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed.
Damage to roofs, windows, and vehicles will occur. Tree
damage is likely.
* This dangerous storm will be near...
Walnut around 455 PM CST.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4151 9515 4150 9516 4136 9516 4133 9515
4139 9541 4151 9532 4166 9510 4160 9509
4160 9504 4151 9504
TIME...MOT...LOC 2246Z 206DEG 72KT 4135 9524
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
CA2 follow-up statements
566
WWUS53 KOAX 152258
SVSOAX
Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
458 PM CST Wed Dec 15 2021
IAC155-152308-
/O.CAN.KOAX.TO.W.0028.000000T0000Z-211215T2330Z/
Pottawattamie IA-
458 PM CST Wed Dec 15 2021
...THE TORNADO WARNING FOR NORTHEASTERN POTTAWATTAMIE COUNTY IS
CANCELLED...
The tornadic thunderstorm which prompted the warning has moved out
of the warned area. Therefore, the warning has been cancelled.
A Tornado Watch remains in effect until 800 PM CST for southwestern
Iowa.
LAT...LON 4151 9515 4150 9516 4151 9531 4151 9532
4166 9510 4160 9509 4160 9504 4151 9504
TIME...MOT...LOC 2258Z 206DEG 72KT 4157 9510
$$
IAC165-152330-
/O.CON.KOAX.TO.W.0028.000000T0000Z-211215T2330Z/
Shelby IA-
458 PM CST Wed Dec 15 2021
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 530 PM CST FOR
SOUTHEASTERN SHELBY COUNTY...
At 458 PM CST, a severe thunderstorm capable of producing a tornado
was located 9 miles northeast of Walnut, or 12 miles north of
Atlantic, moving northeast at 85 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
This tornadic thunderstorm will remain over mainly rural areas of
southeastern Shelby County, including the following locations... Elk
Horn Creek Recreation Area.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4151 9515 4150 9516 4151 9531 4151 9532
4166 9510 4160 9509 4160 9504 4151 9504
TIME...MOT...LOC 2258Z 206DEG 72KT 4157 9510
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
CA190
WWUS53 KOAX 152306
SVSOAX
Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
506 PM CST Wed Dec 15 2021
IAC165-152315-
/O.CAN.KOAX.TO.W.0028.000000T0000Z-211215T2330Z/
Shelby IA-
506 PM CST Wed Dec 15 2021
...THE TORNADO WARNING FOR SOUTHEASTERN SHELBY COUNTY IS CANCELLED...
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled. However, a a Tornado
Warning still remains in effect for northern Shelby County until 530
PM.
A Tornado Watch remains in effect until 800 PM CST for southwestern
Iowa.
LAT...LON 4151 9515 4150 9516 4151 9531 4151 9532
4166 9510 4160 9509 4160 9504 4151 9504
TIME...MOT...LOC 2304Z 206DEG 72KT 4171 9501
$$
CAThe office that day
Everything else NWS Omaha, NE issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 15, 3:35 PM CST | Severe Thunderstorm Warning | OAX | Fremont, Harrison, Mills, Pottawattamie | 70 min |
| Dec 15, 3:41 PM CST | Severe Thunderstorm Warning | OAX | Harrison, Monona | 64 min |
| Dec 15, 3:55 PM CST | Severe Thunderstorm Warning | OAX | Fremont, Harrison, Mills, Montgomery, Page, Pottawattamie and 1 more | 80 min |
| Dec 15, 4:01 PM CST | Tornado Warning | OAX | Fremont, Mills | 14 min |
| Dec 15, 4:12 PM CST | Tornado Warning | OAX | Fremont, Mills | 33 min |
| Dec 15, 4:16 PM CST | Tornado Warning | OAX | Harrison, Pottawattamie | 17 min |
| Dec 15, 4:21 PM CST | Tornado Warning | OAX | Pottawattamie | 24 min |
| Dec 15, 4:30 PM CST | Tornado Warning | OAX | Mills, Montgomery, Pottawattamie | 30 min |
| Dec 15, 4:31 PM CST | Tornado Warning | OAX | Harrison, Monona, Shelby | 13 min |
| Dec 15, 4:37 PM CST | Tornado Warning | OAX | Harrison, Shelby | 23 min |
| Dec 15, 4:54 PM CST | Tornado Warning | OAX | Montgomery, Page | 15 min |
| Dec 15, 4:55 PM CST | Tornado Warning | OAX | Shelby | 14 min |
Nearby
Tornado Warnings in Iowa, 2021Every tornado warning in 2021Tornadoes 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.