Alert archive / Iowa / Tornado Warnings in 2021

Tornado Warning 38, NWS Des Moines, IA

December 15, 2021Sac County, Iowa

NWS Des Moines, IA issued this tornado warning at Dec 15, 2021, 5:07 PM CST for Sac County, Iowa. It was in force for 27 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, 5:07 PM CST (23:07 UTC)
Expired: Dec 15, 2021, 5:34 PM CST
In force: 27 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Sac County, IA

The radar

The Des Moines radar (KDMX), 138 km from the middle of the area, began a volume at 23:12 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, 11.1 hours before the alert went out and 161 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.

135 
WFUS53 KDMX 152307
TORDMX
IAC161-152345-
/O.NEW.KDMX.TO.W.0038.211215T2307Z-211215T2345Z/

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

The National Weather Service in Des Moines  has issued a

* Tornado Warning for...
  Sac County in west central Iowa...

* Until 545 PM CST.
    
* At 507 PM CST, a severe thunderstorm capable of producing a tornado
  was located near Odebolt, or 13 miles southeast of Ida Grove,
  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...
  Odebolt around 510 PM CST.
  Lake View around 515 PM CST.
  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 4256 9492 4221 9510 4221 9531 4256 9532
TIME...MOT...LOC 2307Z 212DEG 63KT 4223 9525 

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

$$

Cogil

2 follow-up statements

195 
WWUS53 KDMX 152323
SVSDMX

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

IAC161-152345-
/O.CON.KDMX.TO.W.0038.000000T0000Z-211215T2345Z/
Sac IA-
523 PM CST Wed Dec 15 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 545 PM CST FOR
NORTHEASTERN SAC COUNTY...
    
At 523 PM CST, a severe thunderstorm capable of producing a tornado
was located near Sac City, moving north at 55 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
northeastern Sac County, including the following locations... Nemaha.

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 4256 9492 4233 9505 4239 9513 4256 9514
TIME...MOT...LOC 2323Z 197DEG 48KT 4242 9506 

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

$$

Cogil

356 
WWUS53 KDMX 152334 RRA
SVSDMX

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

IAC161-152344-
/O.CAN.KDMX.TO.W.0038.000000T0000Z-211215T2345Z/
Sac IA-
534 PM CST Wed Dec 15 2021

...THE TORNADO WARNING FOR NORTHEASTERN SAC COUNTY IS CANCELLED...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning has
been cancelled.

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

LAT...LON 4256 9492 4233 9505 4239 9513 4256 9514
TIME...MOT...LOC 2334Z 212DEG 63KT 4260 9491 

$$

Cogil

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, 4:53 PM CST	Tornado Warning	DMX	Adair, Audubon, Cass, Guthrie	33 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.