Alert archive / Iowa / Tornado Warnings in 2021

Tornado Warning 37, NWS Des Moines, IA

December 15, 20214 counties in Iowa

NWS Des Moines, IA issued this tornado warning at Dec 15, 2021, 4:53 PM CST for 4 counties in Iowa. It was in force for 33 min. 8 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, 4:53 PM CST (22:53 UTC)
Expired: Dec 15, 2021, 5:26 PM CST
In force: 33 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.0 in

Counties Adair County, IA, Audubon County, IA, Cass County, IA, Guthrie County, IA

The radar

The Des Moines radar (KDMX), 108 km from the middle of the area, began a volume at 22:57 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, 5:01 PM CST	TORNADO	3 Ssw Brayton, IA	STORM CHASER REPORTED FLIPPED SEMIS ON I-80 AND POWER FLASHES ASSOCIATED WITH A TORNADO.
Dec 15, 5:02 PM CST	TORNADO	1 Nw Atlantic, IA	STORM CHASER REPORTED TORNADO ON THE WEST SIDE OF ATLANTIC.
Dec 15, 5:04 PM CST	TORNADO	Exira, IA	CORRECTS PREVIOUS TORNADO REPORT FROM EXIRA. DAMAGE TO MULTIPLE TO BARN BUILDINGS NEAR EXIRA. DELAYED REPORT VIA SOCIAL MEDIA PHOTOS. TIME ESTIMATED VIA RADAR.
Dec 15, 5:07 PM CST	TORNADO	4 Se Audubon, IA	DELAYED REPORT. PICTURES CAME IN VIA EMAIL EAST OF HAMLIN, IA. TIME ESTIMATED BASED ON RADAR AND OTHER REPORTS IN AUDUBON COUNTY.
Dec 15, 5:11 PM CST	TSTM WND GST 88	Audubon, IA	PWS RECORDED WIND GUST OF 88 MPH.
Dec 15, 5:12 PM CST	TSTM WND GST 76	Adair, IA	PWS RECORDED A 76 MPH WIND GUST.
Dec 15, 5:15 PM CST	TSTM WND GST 80	2 S Adair, IA	EM REPORTS 80+ MPH WINDS, ZERO VISIBILITY SOUTH OF ADAIR.
Dec 15, 5:17 PM CST	TSTM WND GST 65	8 W Guthrie Center, IA	EM REPORTS 1/2 INCH HAIL AND ESTIMATED 65 MPH WIND, HWY 44 AND FRONTIER ROAD IN GUTHRIE CO.

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, 10.9 hours before the alert went out and 117 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.

943 
WFUS53 KDMX 152253
TORDMX
IAC001-009-029-077-152345-
/O.NEW.KDMX.TO.W.0037.211215T2253Z-211215T2345Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Des Moines IA
453 PM CST Wed Dec 15 2021

The National Weather Service in Des Moines  has issued a

* Tornado Warning for...
  Cass County in southwestern Iowa...
  Southwestern Guthrie County in west central Iowa...
  Audubon County in west central Iowa...
  Northwestern Adair County in southwestern Iowa...

* Until 545 PM CST.
    
* At 452 PM CST, a severe thunderstorm capable of producing a tornado
  was located near Atlantic, 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 tornadic thunderstorm will remain over mainly rural areas of
  Cass, southwestern Guthrie, Audubon and northwestern Adair
  Counties, including the following locations... Exira, Lake Anita
  State Park, Adair, Kimballton, Anita, Wiota, Elk Horn, Lewis,
  Brayton and Audubon County Airport.

This includes Interstate 80 between mile markers 50 and 80.
 
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 4150 9515 4151 9504 4160 9504 4160 9509
      4163 9509 4184 9481 4159 9443 4118 9500
      4130 9516
TIME...MOT...LOC 2252Z 226DEG 65KT 4139 9508 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...0.00 IN

$$

Martin

2 follow-up statements

085 
WWUS53 KDMX 152303
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
503 PM CST Wed Dec 15 2021

IAC001-009-029-077-152345-
/O.CON.KDMX.TO.W.0037.000000T0000Z-211215T2345Z/
Cass IA-Guthrie IA-Audubon IA-Adair IA-
503 PM CST Wed Dec 15 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 545 PM CST FOR
NORTHEASTERN CASS...SOUTHWESTERN GUTHRIE...AUDUBON AND NORTHWESTERN
ADAIR COUNTIES...
    
At 502 PM CST, a confirmed tornado was located 10 miles northeast of
Atlantic, moving northeast at 75 mph.

HAZARD...Damaging tornado.

SOURCE...Weather spotters confirmed tornado crossing Interstate 80 
         north of Atlantic.

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
northeastern Cass, southwestern Guthrie, Audubon and northwestern
Adair Counties, including the following locations... Exira, Wiota,
Elk Horn, Lake Anita State Park, Adair, Kimballton, Brayton, Audubon
County Airport, Anita Municipal Airport and Anita.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. 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 9504 4160 9504 4160 9509 4163 9509
      4184 9481 4159 9443 4130 9484
TIME...MOT...LOC 2302Z 226DEG 65KT 4152 9490 

TORNADO...OBSERVED
MAX HAIL SIZE...0.00 IN

$$

Martin

515 
WWUS53 KDMX 152326
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
526 PM CST Wed Dec 15 2021

IAC001-009-029-077-152335-
/O.CAN.KDMX.TO.W.0037.000000T0000Z-211215T2345Z/
Cass IA-Guthrie IA-Audubon IA-Adair IA-
526 PM CST Wed Dec 15 2021

...THE TORNADO WARNING FOR NORTHEASTERN CASS...SOUTHWESTERN
GUTHRIE...AUDUBON AND NORTHWESTERN ADAIR 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
and west central Iowa.

LAT...LON 4151 9504 4160 9504 4160 9509 4163 9509
      4184 9481 4159 9443 4130 9484
TIME...MOT...LOC 2324Z 226DEG 65KT 4181 9449 

$$

Martin

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 15, 4:13 PM CST	Severe Thunderstorm Warning Destructive damage threat	DMX	Adair, Adams, Audubon, Cass, Guthrie, Ringgold and 2 more	77 min
Dec 15, 4:16 PM CST	Severe Thunderstorm Warning Destructive damage threat	DMX	Carroll, Crawford, Sac	74 min
Dec 15, 4:37 PM CST	Tornado Warning Tornado observed	DMX	Cass	23 min
Dec 15, 4:44 PM CST	Tornado Warning	DMX	Crawford	36 min
Dec 15, 5:07 PM CST	Tornado Warning	DMX	Sac	27 min
Dec 15, 5:10 PM CST	Severe Thunderstorm Warning Destructive damage threat	DMX	Adair, Audubon, Boone, Dallas, Greene, Guthrie and 4 more	80 min
Dec 15, 5:10 PM CST	Tornado Warning	DMX	Carroll, Crawford	35 min
Dec 15, 5:14 PM CST	Tornado Warning	DMX	Audubon, Calhoun, Carroll, Greene, Guthrie	31 min
Dec 15, 5:15 PM CST	Tornado Warning	DMX	Calhoun, Carroll, Crawford, Sac	30 min
Dec 15, 5:18 PM CST	Tornado Warning Tornado observed	DMX	Adair, Boone, Dallas, Greene, Guthrie	42 min
Dec 15, 5:19 PM CST	Severe Thunderstorm Warning Destructive damage threat	DMX	Boone, Calhoun, Carroll, Emmet, Greene, Humboldt and 5 more	71 min
Dec 15, 5:22 PM CST	Severe Thunderstorm Warning Destructive damage threat	DMX	Carroll, Crawford, Sac	23 min
Dec 15, 5:22 PM CST	Severe Thunderstorm Warning Considerable damage threat	DMX	Adair, Adams, Clarke, Decatur, Madison, Ringgold and 3 more	68 min
Dec 15, 5:36 PM CST	Tornado Warning	DMX	Calhoun, Humboldt, Kossuth, Palo Alto, Pocahontas	24 min
Dec 15, 5:38 PM CST	Tornado Warning Tornado observed	DMX	Boone, Calhoun, Greene, Hamilton, Webster	37 min
Dec 15, 5:45 PM CST	Tornado Warning	DMX	Calhoun, Pocahontas, Webster	30 min
Dec 15, 5:52 PM CST	Severe Thunderstorm Warning Destructive damage threat	DMX	Boone, Franklin, Hamilton, Hancock, Hardin, Humboldt and 6 more	53 min
Dec 15, 5:58 PM CST	Tornado Warning	DMX	Hancock, Humboldt, Kossuth, Palo Alto, Pocahontas	32 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.