Alert archive / Iowa / Tornado Warnings in 2021

Tornado Warning 23, NWS Omaha, NE

December 15, 2021Washington County, Nebraska; Harrison County, Pottawattamie County, Iowa

NWS Omaha, NE issued this tornado warning at Dec 15, 2021, 4:16 PM CST for Washington County, Nebraska; Harrison County, Pottawattamie County, Iowa. It was in force for 17 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, 4:16 PM CST (22:16 UTC)
Expired
Dec 15, 2021, 4:33 PM CST
In force
17 min
Issued by
NWS Omaha, NE
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

Counties Harrison County, IA, Pottawattamie County, IA, Washington County, NE

The radar

The Omaha radar (KOAX), 44 km from the middle of the area, began a volume at 22:15 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.

What was reported inside it

TimeReportWhereRemark
Dec 15, 4:22 PM CSTTSTM WND GST 582 W Missouri Valley, IAMESONET STATION UP118 2.2 W MISSOURI VALLEY (UPR).

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.

IssuedProductOfficeLasted
Dec 15, 1:23 PM CSTTornado WatchSPC7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.3 hours before the alert went out and 44 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.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 2021-12-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 2021-12-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 346 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
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

Open this sounding in Storm Lab

The text

As transmitted.

401 
WFUS53 KOAX 152216
TOROAX
IAC085-155-NEC177-152245-
/O.NEW.KOAX.TO.W.0023.211215T2216Z-211215T2245Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Omaha/Valley Nebraska
416 PM CST Wed Dec 15 2021

The National Weather Service in Omaha has issued a

* Tornado Warning for...
  Northwestern Pottawattamie County in southwestern Iowa...
  Western Harrison County in southwestern Iowa...
  Eastern Washington County in east central Nebraska...

* Until 445 PM CST.
    
* At 415 PM CST, a severe thunderstorm capable of producing a tornado
  was located near Blair, or 19 miles north of Omaha, moving
  northeast at 75 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...
  Missouri Valley and Modale around 420 PM CST.
  Mondamin around 425 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 4143 9600 4151 9621 4170 9610 4170 9607
      4172 9609 4181 9604 4174 9575
TIME...MOT...LOC 2215Z 207DEG 64KT 4154 9606 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

Kern
2 follow-up statements
207 
WWUS53 KOAX 152218
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
418 PM CST Wed Dec 15 2021

IAC155-152228-
/O.CAN.KOAX.TO.W.0023.000000T0000Z-211215T2245Z/
Pottawattamie IA-
418 PM CST Wed Dec 15 2021

...THE TORNADO WARNING FOR NORTHWESTERN 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...and east central Nebraska.

LAT...LON 4151 9595 4151 9599 4157 9611 4170 9610
      4170 9607 4172 9609 4181 9604 4174 9575
TIME...MOT...LOC 2218Z 206DEG 62KT 4158 9604 

$$

IAC085-NEC177-152245-
/O.CON.KOAX.TO.W.0023.000000T0000Z-211215T2245Z/
Harrison IA-Washington NE-
418 PM CST Wed Dec 15 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 445 PM CST FOR WESTERN
HARRISON AND NORTHEASTERN WASHINGTON COUNTIES...
    
At 418 PM CST, a severe thunderstorm capable of producing a tornado
was located near Modale, or 21 miles north of Omaha, moving northeast
at 70 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...
  Mondamin around 425 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 9595 4151 9599 4157 9611 4170 9610
      4170 9607 4172 9609 4181 9604 4174 9575
TIME...MOT...LOC 2218Z 206DEG 62KT 4158 9604 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

Kern
813 
WWUS53 KOAX 152233
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
433 PM CST Wed Dec 15 2021

IAC085-NEC177-152243-
/O.CAN.KOAX.TO.W.0023.000000T0000Z-211215T2245Z/
Harrison IA-Washington NE-
433 PM CST Wed Dec 15 2021

...THE TORNADO WARNING FOR WESTERN HARRISON AND NORTHEASTERN
WASHINGTON COUNTIES IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.  However gusty winds are
still possible with this thunderstorm.

A Tornado Watch remains in effect until 800 PM CST for southwestern
Iowa...and east central Nebraska.

LAT...LON 4151 9595 4151 9599 4157 9611 4170 9610
      4170 9607 4172 9609 4181 9604 4174 9575
TIME...MOT...LOC 2232Z 207DEG 64KT 4182 9588 

$$

Kern

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 15, 2:19 PM CSTSevere Thunderstorm Warning Destructive damage threatOAXAntelope, Boone, Butler, Colfax, Madison, Pierce and 2 more56 min
Dec 15, 2:26 PM CSTSevere Thunderstorm Warning Considerable damage threatOAXButler, Gage, Jefferson, Lancaster, Saline, Saunders and 1 more64 min
Dec 15, 2:39 PM CSTTornado WarningOAXBoone, Madison, Platte, Stanton24 min
Dec 15, 2:50 PM CSTTornado WarningOAXColfax, Platte40 min
Dec 15, 2:54 PM CSTSevere Thunderstorm Warning Destructive damage threatOAXCass, Dodge, Douglas, Gage, Johnson, Lancaster and 5 more81 min
Dec 15, 2:59 PM CSTTornado WarningOAXButler, Colfax, Dodge, Platte31 min
Dec 15, 3:06 PM CSTTornado WarningOAXMadison, Platte, Stanton24 min
Dec 15, 3:09 PM CSTSevere Thunderstorm Warning Destructive damage threatOAXBurt, Butler, Colfax, Cuming, Dodge, Saunders and 4 more51 min
Dec 15, 3:13 PM CSTSevere Thunderstorm Warning Considerable damage threatOAXAntelope, Cedar, Colfax, Knox, Madison, Pierce and 3 more62 min
Dec 15, 3:23 PM CSTTornado WarningOAXLancaster, Seward16 min
Dec 15, 3:25 PM CSTTornado WarningOAXColfax, Cuming, Stanton35 min
Dec 15, 3:29 PM CSTTornado WarningOAXMadison, Stanton, Wayne31 min
Dec 15, 3:35 PM CSTSevere Thunderstorm Warning Destructive damage threatOAXCass, Douglas, Johnson, Nemaha, Otoe, Pawnee and 3 more70 min
Dec 15, 3:41 PM CSTSevere Thunderstorm Warning Destructive damage threatOAXBurt, Cuming, Thurston, Washington64 min
Dec 15, 3:45 PM CSTTornado WarningOAXDouglas, Saunders30 min
Dec 15, 3:45 PM CSTTornado Warning Tornado observedOAXCuming, Thurston45 min
Dec 15, 3:54 PM CSTTornado Warning Tornado observedOAXDodge, Douglas, Washington28 min
Dec 15, 4:01 PM CSTTornado WarningOAXCass, Otoe14 min
Dec 15, 4:11 PM CSTTornado WarningOAXNemaha, Pawnee, Richardson34 min
Dec 15, 4:12 PM CSTTornado WarningOAXCass33 min
Dec 15, 5:08 PM CSTBlowing Dust AdvisoryOAXCass, Gage, Jefferson, Johnson, Lancaster, Nemaha and 5 more4 hr
Dec 15, 3:55 PM CSTSevere Thunderstorm Warning Destructive damage threatOAXFremont, Harrison, Mills, Montgomery, Page, Pottawattamie and 1 more80 min
Dec 15, 4:21 PM CSTTornado WarningOAXPottawattamie24 min
Dec 15, 4:30 PM CSTTornado WarningOAXMills, Montgomery, Pottawattamie30 min
Dec 15, 4:31 PM CSTTornado WarningOAXHarrison, Monona, Shelby13 min
Dec 15, 4:37 PM CSTTornado Warning Tornado observedOAXHarrison, Shelby23 min
Dec 15, 4:46 PM CSTTornado WarningOAXPottawattamie, Shelby20 min
Dec 15, 4:54 PM CSTTornado WarningOAXMontgomery, Page15 min
Dec 15, 4:55 PM CSTTornado WarningOAXShelby14 min

Nearby

Tornado Warnings in Iowa, 2021Tornado Warnings in Nebraska, 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.