Alert archive / Iowa / Tornado Warnings in 2021

Tornado Warning 29, NWS Omaha, NE

December 15, 2021Montgomery County, Page County, Iowa

NWS Omaha, NE issued this tornado warning at Dec 15, 2021, 4:54 PM CST for Montgomery County, Page County, Iowa. It was in force for 15 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Dec 15, 2021, 4:54 PM CST (22:54 UTC)
Expired: Dec 15, 2021, 5:09 PM CST
In force: 15 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

Counties Montgomery County, IA, Page County, IA

The radar

The Omaha radar (KOAX), 115 km from the middle of the area, began a volume at 22:54 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.

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, 10.9 hours before the alert went out and 115 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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.

538 
WFUS53 KOAX 152254
TOROAX
IAC137-145-152330-
/O.NEW.KOAX.TO.W.0029.211215T2254Z-211215T2330Z/

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

The National Weather Service in Omaha has issued a

* Tornado Warning for...
  Eastern Montgomery County in southwestern Iowa...
  North central Page County in southwestern Iowa...

* Until 530 PM CST.
    
* At 454 PM CST, a severe thunderstorm capable of producing a tornado
  was located near Stanton, or 20 miles west of Corning, moving
  northeast at 80 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
  eastern Montgomery and north central Page Counties, including the
  following locations... Grant and Viking Lake State Park.

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 4079 9520 4088 9520 4116 9504 4116 9493
      4094 9493
TIME...MOT...LOC 2254Z 224DEG 71KT 4092 9511 

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

$$

BLB

2 follow-up statements

311 
WWUS53 KOAX 152303
SVSOAX

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

IAC145-152313-
/O.CAN.KOAX.TO.W.0029.000000T0000Z-211215T2330Z/
Page IA-
503 PM CST Wed Dec 15 2021

...THE TORNADO WARNING FOR NORTH CENTRAL PAGE 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 4090 9500 4101 9505 4116 9493 4094 9493
TIME...MOT...LOC 2303Z 221DEG 75KT 4103 9496 

$$

IAC137-152330-
/O.CON.KOAX.TO.W.0029.000000T0000Z-211215T2330Z/
Montgomery IA-
503 PM CST Wed Dec 15 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 530 PM CST FOR
SOUTHEASTERN MONTGOMERY COUNTY...
    
At 503 PM CST, a severe thunderstorm capable of producing a tornado
was located 6 miles north of Villisca, or 11 miles west of Corning,
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.

Locations impacted include...
Villisca.

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 4090 9500 4101 9505 4116 9493 4094 9493
TIME...MOT...LOC 2303Z 221DEG 75KT 4103 9496 

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

$$

BLB

032 
WWUS53 KOAX 152309
SVSOAX

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

IAC137-152318-
/O.CAN.KOAX.TO.W.0029.000000T0000Z-211215T2330Z/
Montgomery IA-
509 PM CST Wed Dec 15 2021

...THE TORNADO WARNING FOR SOUTHEASTERN MONTGOMERY COUNTY IS
CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.

A severe thunderstorm warning remains in effect.

A Tornado Watch remains in effect until 800 PM CST for southwestern
Iowa.

LAT...LON 4090 9500 4101 9505 4116 9493 4094 9493
TIME...MOT...LOC 2307Z 224DEG 71KT 4111 9485 

$$

BLB

The 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 Destructive damage threat	OAX	Fremont, Harrison, Mills, Pottawattamie	70 min
Dec 15, 3:41 PM CST	Severe Thunderstorm Warning Destructive damage threat	OAX	Harrison, Monona	64 min
Dec 15, 3:55 PM CST	Severe Thunderstorm Warning Destructive damage threat	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 Tornado observed	OAX	Harrison, Shelby	23 min
Dec 15, 4:46 PM CST	Tornado Warning	OAX	Pottawattamie, Shelby	20 min
Dec 15, 4:55 PM CST	Tornado Warning	OAX	Shelby	14 min

Nearby

Tornado Warnings in Iowa, 2021 Every tornado warning in 2021 Tornadoes 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.