Alert archive / Iowa / Tornado Warnings in 2021

Tornado Warning 41, NWS Des Moines, IA

December 15, 20214 counties in Iowa

NWS Des Moines, IA issued this tornado warning at Dec 15, 2021, 5:15 PM CST for 4 counties in Iowa. It was in force for 30 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, 5:15 PM CST (23:15 UTC)
Expired
Dec 15, 2021, 5:45 PM CST
In force
30 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

Counties Calhoun County, IA, Carroll County, IA, Crawford County, IA, Sac County, IA

The radar

The Des Moines radar (KDMX), 121 km from the middle of the area, began a volume at 23:19 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.

IssuedProductOfficeLasted
Dec 15, 1:23 PM CSTTornado WatchSPC7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.3 hours before the alert went out and 158 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.

285 
WFUS53 KDMX 152315
TORDMX
IAC025-027-047-161-152345-
/O.NEW.KDMX.TO.W.0041.211215T2315Z-211215T2345Z/

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

The National Weather Service in Des Moines  has issued a

* Tornado Warning for...
  Southeastern Sac County in west central Iowa...
  West central Calhoun County in west central Iowa...
  Northeastern Crawford County in west central Iowa...
  Northwestern Carroll County in west central Iowa...

* Until 545 PM CST.
    
* At 515 PM CST, a severe thunderstorm capable of producing a tornado
  was located near Black Hawk Lake, or 13 miles south of Sac City,
  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...
  Sac City around 525 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 4216 9506 4221 9516 4250 9492 4242 9471
TIME...MOT...LOC 2315Z 215DEG 61KT 4224 9504 

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

$$

Cogil
2 follow-up statements
795 
WWUS53 KDMX 152325
SVSDMX

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

IAC047-152335-
/O.CAN.KDMX.TO.W.0041.000000T0000Z-211215T2345Z/
Crawford IA-
525 PM CST Wed Dec 15 2021

...THE TORNADO WARNING FOR NORTHEASTERN CRAWFORD COUNTY IS
CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. 

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

LAT...LON 4220 9501 4233 9505 4250 9492 4242 9471
TIME...MOT...LOC 2325Z 215DEG 61KT 4238 9491 

$$

IAC025-027-161-152345-
/O.CON.KDMX.TO.W.0041.000000T0000Z-211215T2345Z/
Sac IA-Calhoun IA-Carroll IA-
525 PM CST Wed Dec 15 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 545 PM CST FOR
SOUTHEASTERN SAC...WEST CENTRAL CALHOUN AND NORTHWESTERN CARROLL
COUNTIES...
    
At 525 PM CST, a severe thunderstorm capable of producing a tornado
was located near Sac City, 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 tornadic thunderstorm will remain over mainly rural areas of
southeastern Sac, west central Calhoun and northwestern Carroll
Counties, including the following locations... Lytton, Blackhawk Lake
State Park and Sac City Municipal Airport.

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 4220 9501 4233 9505 4250 9492 4242 9471
TIME...MOT...LOC 2325Z 215DEG 61KT 4238 9491 

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

$$

Cogil
691 
WWUS53 KDMX 152338
SVSDMX

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

IAC025-027-161-152348-
/O.EXP.KDMX.TO.W.0041.000000T0000Z-211215T2345Z/
Sac IA-Calhoun IA-Carroll IA-
538 PM CST Wed Dec 15 2021

...THE TORNADO WARNING FOR SOUTHEASTERN SAC...WEST CENTRAL CALHOUN
AND NORTHWESTERN CARROLL COUNTIES WILL EXPIRE AT 545 PM CST...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.

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

LAT...LON 4220 9501 4233 9505 4250 9492 4242 9471
TIME...MOT...LOC 2338Z 215DEG 61KT 4255 9475 

$$

Cogil

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 15, 4:13 PM CSTSevere Thunderstorm Warning Destructive damage threatDMXAdair, Adams, Audubon, Cass, Guthrie, Ringgold and 2 more77 min
Dec 15, 4:16 PM CSTSevere Thunderstorm Warning Destructive damage threatDMXCarroll, Crawford, Sac74 min
Dec 15, 4:37 PM CSTTornado Warning Tornado observedDMXCass23 min
Dec 15, 4:44 PM CSTTornado WarningDMXCrawford36 min
Dec 15, 4:53 PM CSTTornado WarningDMXAdair, Audubon, Cass, Guthrie33 min
Dec 15, 5:07 PM CSTTornado WarningDMXSac27 min
Dec 15, 5:10 PM CSTSevere Thunderstorm Warning Destructive damage threatDMXAdair, Audubon, Boone, Dallas, Greene, Guthrie and 4 more80 min
Dec 15, 5:10 PM CSTTornado WarningDMXCarroll, Crawford35 min
Dec 15, 5:14 PM CSTTornado WarningDMXAudubon, Calhoun, Carroll, Greene, Guthrie31 min
Dec 15, 5:18 PM CSTTornado Warning Tornado observedDMXAdair, Boone, Dallas, Greene, Guthrie42 min
Dec 15, 5:19 PM CSTSevere Thunderstorm Warning Destructive damage threatDMXBoone, Calhoun, Carroll, Emmet, Greene, Humboldt and 5 more71 min
Dec 15, 5:22 PM CSTSevere Thunderstorm Warning Destructive damage threatDMXCarroll, Crawford, Sac23 min
Dec 15, 5:22 PM CSTSevere Thunderstorm Warning Considerable damage threatDMXAdair, Adams, Clarke, Decatur, Madison, Ringgold and 3 more68 min
Dec 15, 5:36 PM CSTTornado WarningDMXCalhoun, Humboldt, Kossuth, Palo Alto, Pocahontas24 min
Dec 15, 5:38 PM CSTTornado Warning Tornado observedDMXBoone, Calhoun, Greene, Hamilton, Webster37 min
Dec 15, 5:45 PM CSTTornado WarningDMXCalhoun, Pocahontas, Webster30 min
Dec 15, 5:52 PM CSTSevere Thunderstorm Warning Destructive damage threatDMXBoone, Franklin, Hamilton, Hancock, Hardin, Humboldt and 6 more53 min
Dec 15, 5:58 PM CSTTornado WarningDMXHancock, Humboldt, Kossuth, Palo Alto, Pocahontas32 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.