Alert archive / Iowa / Tornado Warnings in 2021

Tornado Warning 24, NWS Omaha, NE

December 15, 2021Pottawattamie County, Iowa

NWS Omaha, NE issued this tornado warning at Dec 15, 2021, 4:21 PM CST for Pottawattamie County, Iowa. It was in force for 24 min. 12 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: Dec 15, 2021, 4:21 PM CST (22:21 UTC)
Expired: Dec 15, 2021, 4:45 PM CST
In force: 24 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Pottawattamie County, IA

The radar

The Omaha radar (KOAX), 47 km from the middle of the area, began a volume at 22:22 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, 4:21 PM CST	TSTM WND DMG	1 Ene Council Bluffs, IA	NINE LOADED COAL CARS ROLLED OFF TRACKS.
Dec 15, 4:24 PM CST	TSTM WND DMG	5 W Mcclelland, IA	FIRE CHIEF REPORTED POWER LINES AND POLES DOWN FOR ABOUT A 1/4 MILE FROM HOMESTEAD AVE TO L-34 ALONG RAILROAD HIGHWAY.
Dec 15, 4:24 PM CST	TORNADO	4 Wsw Mcclelland, IA	A NARROW BUT STRONG TORNADO TRACKED ALONG ROAD L34 THROUGH SHERWOOD COUNTRY ESTATES BEFORE ENDING NEAR JUNIPER ROAD. THE MAXIMUM DAMAGE WAS SUSTAINED TO A HOME IN SHERWOOD COUNTRY ESTATES WHERE THE NARROW TORNADO REMOVED THE MAJORITY OF A HOMES ROOF AND DAMAGE
Dec 15, 4:25 PM CST	TSTM WND DMG	3 Wnw Mcclelland, IA	MAJOR HOME DAMAGE IN WESTON.
Dec 15, 4:29 PM CST	TSTM WND DMG	4 W Underwood, IA	ROOF BLOWN OFF A HOUSE ON L-34 WEST OF UNDERWOOD.
Dec 15, 4:31 PM CST	TORNADO	2 E Underwood, IA	A NARROW EF-2 TORNADO BEGAN PRODUCING DAMAGE NEAR MAHOGANY ROAD AND 290TH ST AND TRACKED NORTH NORTHEAST INTO THE SOUTHEAST EDGE OF NEOLA AND THEN CAUSED INTERMITTENT DAMAGE NEAR RAILROAD HIGHWAY NORTH OF NEOLA. THE MOST SIGNIFICANT DAMAGE WAS TO A HOME ALONG
Dec 15, 4:32 PM CST	TORNADO	2 Sw Neola, IA	FROM VIDEO AND TDS. TORNADO ON THE GROUND FOR AT LEAST 2 MINUTES. DAMAGE REPORTED IN NEOLA.
Dec 15, 4:35 PM CST	NON-TSTM WND GST 79	5 Ene Council Bluffs, IA	AWOS STATION KCBF COUNCIL BLUFFS AIRPORT.
Dec 15, 4:36 PM CST	TSTM WND GST 79	5 Ene Council Bluffs, IA
Dec 15, 4:38 PM CST	TSTM WND DMG	1 Ne Underwood, IA	LARGE GARAGE DOORS ON CITY BUILDING BLOWN IN.
Dec 15, 4:38 PM CST	TSTM WND GST 80	2 Se Underwood, IA
Dec 15, 4:53 PM CST	TSTM WND DMG	1 Se Shelby, IA	SEMI ROLLED OVER ON I-80W PER TWITTER PHOTO.

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, 10.4 hours before the alert went out and 47 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.

765 
WFUS53 KOAX 152221
TOROAX
IAC155-152300-
/O.NEW.KOAX.TO.W.0024.211215T2221Z-211215T2300Z/

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

The National Weather Service in Omaha has issued a

* Tornado Warning for...
  Central Pottawattamie County in southwestern Iowa...

* Until 500 PM CST.
    
* At 420 PM CST, a severe thunderstorm capable of producing a tornado
  was located over eastern Council Bluffs, or 11 miles east of Omaha,
  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...
  Underwood around 430 PM CST.
  Minden around 435 PM CST.
  Shelby around 440 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 4116 9572 4116 9584 4119 9585 4122 9592
      4123 9591 4126 9592 4128 9591 4128 9589
      4129 9587 4132 9588 4151 9576 4151 9532
TIME...MOT...LOC 2220Z 217DEG 74KT 4124 9579 

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

$$

CA

1 follow-up statement

071 
WWUS53 KOAX 152245 RRA
SVSOAX

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

IAC155-152253-
/O.CAN.KOAX.TO.W.0024.000000T0000Z-211215T2300Z/
Pottawattamie IA-
445 PM CST Wed Dec 15 2021

...THE TORNADO WARNING FOR CENTRAL POTTAWATTAMIE COUNTY IS
CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled. However, a Tornado 
Warning still remains in effect for eastern Pottawattamie County 
until 5 PM.

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

LAT...LON 4116 9572 4116 9584 4119 9585 4122 9592
      4123 9591 4126 9592 4128 9591 4128 9589
      4129 9587 4132 9588 4151 9576 4151 9532
TIME...MOT...LOC 2243Z 217DEG 74KT 4163 9539 

$$

CA

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, 4:30 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, 4:54 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, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.